Publications

Stanford University Professor of Pulmonary and Critical Care Medicine

Publications

  • Rat microbial biogeography and age-dependent lactic acid bacteria in healthy lungs. Lab animal Zhao, L., Cunningham, C. M., Andruska, A. M., Schimmel, K., Ali, M. K., Kim, D., Gu, S., Chang, J. L., Spiekerkoetter, E., Nicolls, M. R. 2024; 53 (2): 43-55

    Abstract

    The laboratory rat emerges as a useful tool for studying the interaction between the host and its microbiome. To advance principles relevant to the human microbiome, we systematically investigated and defined the multitissue microbial biogeography of healthy Fischer 344 rats across their lifespan. Microbial community profiling data were extracted and integrated with host transcriptomic data from the Sequencing Quality Control consortium. Unsupervised machine learning, correlation, taxonomic diversity and abundance analyses were performed to determine and characterize the rat microbial biogeography and identify four intertissue microbial heterogeneity patterns (P1-P4). We found that the 11 body habitats harbored a greater diversity of microbes than previously suspected. Lactic acid bacteria (LAB) abundance progressively declined in lungs from breastfed newborn to adolescence/adult, and was below detectable levels in elderly rats. Bioinformatics analyses indicate that the abundance of LAB may be modulated by the lung-immune axis. The presence and levels of LAB in lungs were further evaluated by PCR in two validation datasets. The lung, testes, thymus, kidney, adrenal and muscle niches were found to have age-dependent alterations in microbial abundance. The 357 microbial signatures were positively correlated with host genes in cell proliferation (P1), DNA damage repair (P2) and DNA transcription (P3). Our study established a link between the metabolic properties of LAB with lung microbiota maturation and development. Breastfeeding and environmental exposure influence microbiome composition and host health and longevity. The inferred rat microbial biogeography and pattern-specific microbial signatures could be useful for microbiome therapeutic approaches to human health and life quality enhancement.

    View details for DOI 10.1038/s41684-023-01322-x

    View details for PubMedID 38297075

    View details for PubMedCentralID PMC10834367

  • Pericytes contribute to pulmonary vascular remodeling via HIF2α signaling. EMBO reports Kim, H., Liu, Y., Kim, J., Kim, Y., Klouda, T., Fisch, S., Baek, S. H., Liu, T., Dahlberg, S., Hu, C. J., Tian, W., Jiang, X., Kosmas, K., Christou, H. A., Korman, B. D., Vargas, S. O., Wu, J. C., Stenmark, K. R., Perez, V. d., Nicolls, M. R., Raby, B. A., Yuan, K. 2024

    Abstract

    Vascular remodeling is the process of structural alteration and cell rearrangement of blood vessels in response to injury and is the cause of many of the world's most afflicted cardiovascular conditions, including pulmonary arterial hypertension (PAH). Many studies have focused on the effects of vascular endothelial cells and smooth muscle cells (SMCs) during vascular remodeling, but pericytes, an indispensable cell population residing largely in capillaries, are ignored in this maladaptive process. Here, we report that hypoxia-inducible factor 2α (HIF2α) expression is increased in the lung tissues of PAH patients, and HIF2α overexpressed pericytes result in greater contractility and an impaired endothelial-pericyte interaction. Using single-cell RNAseq and hypoxia-induced pulmonary hypertension (PH) models, we show that HIF2α is a major molecular regulator for the transformation of pericytes into SMC-like cells. Pericyte-selective HIF2α overexpression in mice exacerbates PH and right ventricular hypertrophy. Temporal cellular lineage tracing shows that HIF2α overexpressing reporter NG2+ cells (pericyte-selective) relocate from capillaries to arterioles and co-express SMA. This novel insight into the crucial role of NG2+ pericytes in pulmonary vascular remodeling via HIF2α signaling suggests a potential drug target for PH.

    View details for DOI 10.1038/s44319-023-00054-w

    View details for PubMedID 38243138

    View details for PubMedCentralID 9199463

  • Single-Cell Imaging Maps Inflammatory Cell Subsets to Pulmonary Arterial Hypertension Vasculopathy. American journal of respiratory and critical care medicine Ferrian, S., Cao, A., McCaffrey, E. F., Saito, T., Greenwald, N. F., Nicolls, M. R., Bruce, T., Zamanian, R. T., Del Rosario, P., Rabinovitch, M., Angelo, M. 2023

    Abstract

    Rationale: Elucidating the immune landscape within and surrounding pulmonary arteries (PAs) is critical in understanding immune-driven vascular pathology in pulmonary arterial hypertension (PAH). Although more severe vascular pathology is often observed in hereditary (H)PAH patients with BMPR2 mutations, the involvement of specific immune cell subsets remains unclear. Methods: We used cutting-edge multiplexed ion beam imaging by time-of-flight (MIBI-TOF) to compare PAs and adjacent tissue in PAH lungs (idiopathic (I)PAH and HPAH) with unused donor lungs. Measurements: We quantified immune cells' proximity and abundance, focusing on those linked to vascular pathology, and evaluated their impact on pulmonary arterial smooth muscle cells (SMCs) and endothelial cells (ECs). Results: Distinct immune infiltration patterns emerged between PAH subtypes, with intramural involvement independently linked to PA occlusive changes. Notably, we identified monocyte-derived dendritic cells (mo-DCs) within PA subendothelial and adventitial regions, influencing vascular remodeling by promoting SMC proliferation and suppressing endothelial gene expression across PAH subtypes. In HPAH patients, pronounced immune dysregulation encircled PA walls, characterized by heightened perivascular inflammation involving TIM-3+ T cells. This correlated with an expanded DC subset expressing IDO-1, TIM-3, and SAMHD1, alongside increased neutrophils, SMCs, and α-SMA+ECs, reinforcing the severity of pulmonary vascular lesions. Conclusions: This study presents the first architectural map of PAH lungs, connecting immune subsets not only with specific PA lesions but also with heightened severity in HPAH compared to IPAH. Our findings emphasize the therapeutic potential of targeting mo-DCs, neutrophils, cellular interactions, and immune responses to alleviate severe vascular pathology in IPAH and HPAH.

    View details for DOI 10.1164/rccm.202209-1761OC

    View details for PubMedID 37934691

  • Abnormal Lymphatic Sphingosine-1-Phosphate Signaling Aggravates Lymphatic Dysfunction and Tissue Inflammation. Circulation Kim, D., Tian, W., Wu, T. T., Xiang, M., Vinh, R., Chang, J. L., Gu, S., Lee, S., Zhu, Y., Guan, T., Schneider, E. C., Bao, E., Dixon, J. B., Kao, P., Pan, J., Rockson, S. G., Jiang, X., Nicolls, M. R. 2023

    Abstract

    Lymphedema is a global health problem with no effective drug treatment. Enhanced T-cell immunity and abnormal lymphatic endothelial cell (LEC) signaling are promising therapeutic targets for this condition. Sphingosine-1-phosphate (S1P) mediates a key signaling pathway required for normal LEC function, and altered S1P signaling in LECs could lead to lymphatic disease and pathogenic T-cell activation. Characterizing this biology is relevant for developing much needed therapies.Human and mouse lymphedema was studied. Lymphedema was induced in mice by surgically ligating the tail lymphatics. Lymphedematous dermal tissue was assessed for S1P signaling. To verify the role of altered S1P signaling effects in lymphatic cells, LEC-specific S1pr1-deficient (S1pr1LECKO) mice were generated. Disease progression was quantified by tail-volumetric and -histopathologic measurements over time. LECs from mice and humans, with S1P signaling inhibition, were then cocultured with CD4 T cells, followed by an analysis of CD4 T-cell activation and pathway signaling. Last, animals were treated with a monoclonal antibody specific to P-selectin to assess its efficacy in reducing lymphedema and T-cell activation.Human and experimental lymphedema tissues exhibited decreased LEC S1P signaling through S1P receptor 1 (S1PR1). LEC S1pr1 loss-of-function exacerbated lymphatic vascular insufficiency, tail swelling, and increased CD4 T-cell infiltration in mouse lymphedema. LECs, isolated from S1pr1LECKO mice and cocultured with CD4 T cells, resulted in augmented lymphocyte differentiation. Inhibiting S1PR1 signaling in human dermal LECs promoted T-helper type 1 and 2 (Th1 and Th2) cell differentiation through direct cell contact with lymphocytes. Human dermal LECs with dampened S1P signaling exhibited enhanced P-selectin, an important cell adhesion molecule expressed on activated vascular cells. In vitro, P-selectin blockade reduced the activation and differentiation of Th cells cocultured with shS1PR1-treated human dermal LECs. P-selectin-directed antibody treatment improved tail swelling and reduced Th1/Th2 immune responses in mouse lymphedema.This study suggests that reduction of the LEC S1P signaling aggravates lymphedema by enhancing LEC adhesion and amplifying pathogenic CD4 T-cell responses. P-selectin inhibitors are suggested as a possible treatment for this pervasive condition.

    View details for DOI 10.1161/CIRCULATIONAHA.123.064181

    View details for PubMedID 37609838

  • Abnormal lymphatic S1P signaling aggravates lymphatic dysfunction and tissue inflammation. medRxiv : the preprint server for health sciences Kim, D., Tian, W., Wu, T. T., Xiang, M., Vinh, R., Chang, J., Gu, S., Lee, S., Zhu, Y., Guan, T., Schneider, E. C., Bao, E., Dixon, J. B., Kao, P., Pan, J., Rockson, S. G., Jiang, X., Nicolls, M. R. 2023

    Abstract

    BACKGROUND: Lymphedema is a global health problem with no effective drug treatment. Enhanced T cell immunity and abnormal lymphatic endothelial cell (LEC) signaling are promising therapeutic targets for this condition. Sphingosine-1-phosphate (S1P) mediates a key signaling pathway required for normal LEC function, and altered S1P signaling in LECs could lead to lymphatic disease and pathogenic T cell activation. Characterizing this biology is relevant for developing much-needed therapies.METHODS: Human and mouse lymphedema was studied. Lymphedema was induced in mice by surgically ligating the tail lymphatics. Lymphedematous dermal tissue was assessed for S1P signaling. To verify the role of altered S1P signaling effects in lymphatic cells, LEC-specific S1pr1 -deficient ( S1pr1 LECKO ) mice were generated. Disease progression was quantified by tail-volumetric and -histopathological measurements over time. LECs from mice and humans, with S1P signaling inhibition, were then co-cultured with CD4 T cells, followed by an analysis of CD4 T cell activation and pathway signaling. Finally, animals were treated with a monoclonal antibody specific to P-selectin to assess its efficacy in reducing lymphedema and T cell activation.RESULTS: Human and experimental lymphedema tissues exhibited decreased LEC S1P signaling through S1PR1. LEC S1pr1 loss-of-function exacerbated lymphatic vascular insufficiency, tail swelling, and increased CD4 T cell infiltration in mouse lymphedema. LECs, isolated from S1pr1 LECKO mice and co-cultured with CD4 T cells, resulted in augmented lymphocyte differentiation. Inhibiting S1PR1 signaling in human dermal LECs (HDLECs) promoted T helper type 1 and 2 (Th1 and Th2) cell differentiation through direct cell contact with lymphocytes. HDLECs with dampened S1P signaling exhibited enhanced P-selectin, an important cell adhesion molecule expressed on activated vascular cells. In vitro , P-selectin blockade reduced the activation and differentiation of Th cells co-cultured with sh S1PR1 -treated HDLECs. P-selectin-directed antibody treatment improved tail swelling and reduced Th1/Th2 immune responses in mouse lymphedema.CONCLUSION: This study suggests that reduction of the LEC S1P signaling aggravates lymphedema by enhancing LEC adhesion and amplifying pathogenic CD4 T cell responses. P-selectin inhibitors are suggested as a possible treatment for this pervasive condition.Clinical Perspective: What is New?: Lymphatic-specific S1pr1 deletion exacerbates lymphatic vessel malfunction and Th1/Th2 immune responses during lymphedema pathogenesis. S1pr1 -deficient LECs directly induce Th1/Th2 cell differentiation and decrease anti-inflammatory Treg populations. Peripheral dermal LECs affect CD4 T cell immune responses through direct cell contact.LEC P-selectin, regulated by S1PR1 signaling, affects CD4 T cell activation and differentiation.P-selectin blockade improves lymphedema tail swelling and decreases Th1/Th2 population in the diseased skin.What Are the Clinical Implications?: S1P/S1PR1 signaling in LECs regulates inflammation in lymphedema tissue.S1PR1 expression levels on LECs may be a useful biomarker for assessing predisposition to lymphatic disease, such as at-risk women undergoing mastectomyP-selectin Inhibitors may be effective for certain forms of lymphedema.

    View details for DOI 10.1101/2023.06.08.23291175

    View details for PubMedID 37398237

  • Using an Unsupervised Learning Ensemble to Identify and Evaluate PAH Immune Phenotypes Longitudinally During Disease Progression Sweatt, A., Hedlin, H. K., Haddad, F., Lawrie, A., Desai, M., Khatri, P., Nicolls, M. R., Rabinovitch, M., Zamanian, R. T. AMER THORACIC SOC. 2023
  • A Selective Leukotriene B4 Antagonist, Acebilustat, for Treatment of Outpatients With COVID-19 Disease: A Randomized, Double-blind, Placebo-controlled Phase 2 Trial Levitt, J. E., Hedlin, H., Duong, S., Lu, D., Lee, J., Elkarra, N., Pinsky, B., Heffernan, E., Springman, E., Bonilla, H., Parsonnet, J., Zamanian, R. T., Langguth, J., Bollyky, J., Khosla, C., Nicolls, M. R., Desai, M., Moss, R., Rogers, A. AMER THORACIC SOC. 2023
  • Endotyping COPD: hypoxia-inducible factor-2 as a molecular "switch" between the vascular and airway phenotypes? European respiratory review : an official journal of the European Respiratory Society Myronenko, O., Foris, V., Crnkovic, S., Olschewski, A., Rocha, S., Nicolls, M. R., Olschewski, H. 2023; 32 (167)

    Abstract

    COPD is a heterogeneous disease with multiple clinical phenotypes. COPD endotypes can be determined by different expressions of hypoxia-inducible factors (HIFs), which, in combination with individual susceptibility and environmental factors, may cause predominant airway or vascular changes in the lung. The pulmonary vascular phenotype is relatively rare among COPD patients and characterised by out-of-proportion pulmonary hypertension (PH) and low diffusing capacity of the lung for carbon monoxide, but only mild-to-moderate airway obstruction. Its histologic feature, severe remodelling of the small pulmonary arteries, can be mediated by HIF-2 overexpression in experimental PH models. HIF-2 is not only involved in the vascular remodelling but also in the parenchyma destruction. Endothelial cells from human emphysema lungs express reduced HIF-2α levels, and the deletion of pulmonary endothelial Hif-2α leads to emphysema in mice. This means that both upregulation and downregulation of HIF-2 have adverse effects and that HIF-2 may represent a molecular "switch" between the development of the vascular and airway phenotypes in COPD. The mechanisms of HIF-2 dysregulation in the lung are only partly understood. HIF-2 levels may be controlled by NAD(P)H oxidases via iron- and redox-dependent mechanisms. A better understanding of these mechanisms may lead to the development of new therapeutic targets.

    View details for DOI 10.1183/16000617.0173-2022

    View details for PubMedID 36631133

  • Evaluation of acebilustat, a selective inhibitor of leukotriene B4 biosynthesis, for treatment of outpatients with mild-moderate COVID-19 disease: A randomized, double-blind, placebo- controlled Phase 2 trial. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America Levitt, J. E., Hedlin, H., Duong, S., Lu, D., Lee, J., Bunning, B., Elkarra, N., Pinsky, B. A., Heffernan, E., Springman, E., Moss, R. B., Bonilla, H. F., Parsonnet, J., Zamanian, R. T., Langguth, J. J., Bollyky, J., Khosla, C., Nicolls, M. R., Desai, M., Rogers, A. J. 2023

    Abstract

    The vast majority of COVID-19 disease occurs in outpatients where treatment is limited to anti-virals for high-risk subgroups. Acebilustat, a leukotriene B4 (LTB4) inhibitor, has potential to reduce inflammation and symptom duration.In a single-center trial spanning Delta and Omicron variants, outpatients were randomized to 100 mg of oral acebilustat or placebo for 28 days. Patients reported daily symptoms via electronic query through Day 28 with phone follow-up on Day 120 and collected nasal swabs on Days 1-10. The primary outcome was sustained symptom resolution to Day 28. Secondary 28-day outcomes included time to first symptom resolution, area under the curve (AUC) of longitudinal daily symptom scores; duration of viral shedding through Day 10; and symptoms on Day 120.Sixty participants were randomized to each study arm. At enrollment, median duration and number of symptoms were 4 (IQR 3-5) days and 9 (IQR 7-11) symptoms. Most patients (90%) were vaccinated with 73% having neutralizing antibodies. A minority (44%) of participants (35% in the acebilustat arm and 53% in placebo) had sustained symptom resolution at Day 28 (HR 0.6, 95% CI 0.34-1.04, p = 0.07 favoring placebo). There was no difference in mean AUC of symptom scores over 28 days (difference in mean of AUC 9.4, 95% CI -42.1-60.9, p=0.72). Acebilustat did not impact viral shedding or symptoms at Day 120.Sustained symptoms through Day 28 were common in this low-risk population. Despite this, LTB4 antagonism with acebilustat did not shorten symptom duration in outpatients with COVID-19.

    View details for DOI 10.1093/cid/ciad187

    View details for PubMedID 36996150

  • A p53-TLR3 axis ameliorates pulmonary hypertension by inducing BMPR2 via IRF3. iScience Bhagwani, A. R., Ali, M., Piper, B., Liu, M., Hudson, J., Kelly, N., Bogamuwa, S., Yang, H., Londino, J. D., Bednash, J. S., Farkas, D., Mallampalli, R. K., Nicolls, M. R., Ryan, J. J., Thompson, A. A., Chan, S. Y., Gomez, D., Goncharova, E. A., Farkas, L. 2023; 26 (2): 105935

    Abstract

    Pulmonary arterial hypertension (PAH) features pathogenic and abnormal endothelial cells (ECs), and one potential origin is clonal selection. We studied the role of p53 and toll-like receptor 3 (TLR3) in clonal expansion and pulmonary hypertension (PH) via regulation of bone morphogenetic protein (BMPR2) signaling. ECs of PAH patients had reduced p53 expression. EC-specific p53 knockout exaggerated PH, and clonal expansion reduced p53 and TLR3 expression in rat lung CD117+ ECs. Reduced p53 degradation (Nutlin 3a) abolished clonal EC expansion, induced TLR3 and BMPR2, and ameliorated PH. Polyinosinic/polycytidylic acid [Poly(I:C)] increased BMPR2 signaling in ECs via enhanced binding of interferon regulatory factor-3 (IRF3) to the BMPR2 promoter and reduced PH in p53-/- mice but not in mice with impaired TLR3 downstream signaling. Our data show that a p53/TLR3/IRF3 axis regulates BMPR2 expression and signaling in ECs. This link can be exploited for therapy of PH.

    View details for DOI 10.1016/j.isci.2023.105935

    View details for PubMedID 36685041

  • Decreasing ELK3 expression improves Bone Morphogenetic Protein Receptor 2 signaling and pulmonary vascular cell function in PAH. bioRxiv : the preprint server for biology Ali, M. K., Zhao, L., Perez, V. d., Nicolls, M. R., Spiekerkoetter, E. F. 2023

    Abstract

    ELK3 is upregulated in blood and pulmonary vascular cells of PAH patients and may play a significant role in PAH potentially through modulating BMPR2 signaling.

    View details for DOI 10.1101/2023.01.14.524023

    View details for PubMedID 36711443

    View details for PubMedCentralID PMC9882174

  • PTPN1 Deficiency Modulates BMPR2 Signaling and Induces Endothelial Dysfunction in Pulmonary Arterial Hypertension. Cells Ali, M. K., Tian, X., Zhao, L., Schimmel, K., Rhodes, C. J., Wilkins, M. R., Nicolls, M. R., Spiekerkoetter, E. F. 2023; 12 (2)

    Abstract

    Bone morphogenic protein receptor 2 (BMPR2) expression and signaling are impaired in pulmonary arterial hypertension (PAH). How BMPR2 signaling is decreased in PAH is poorly understood. Protein tyrosine phosphatases (PTPs) play important roles in vascular remodeling in PAH. To identify whether PTPs modify BMPR2 signaling, we used a siRNA-mediated high-throughput screening of 22,124 murine genes in mouse myoblastoma reporter cells using ID1 expression as readout for BMPR2 signaling. We further experimentally validated the top hit, PTPN1 (PTP1B), in healthy human pulmonary arterial endothelial cells (PAECs) either silenced by siRNA or exposed to hypoxia and confirmed its relevance to PAH by measuring PTPN1 levels in blood and PAECs collected from PAH patients. We identified PTPN1 as a novel regulator of BMPR2 signaling in PAECs, which is downregulated in the blood of PAH patients, and documented that downregulation of PTPN1 is linked to endothelial dysfunction in PAECs. These findings point to a potential involvement for PTPN1 in PAH and will aid in our understanding of the molecular mechanisms involved in the disease.

    View details for DOI 10.3390/cells12020316

    View details for PubMedID 36672250

  • The Human Respiratory Microbiome: Current Understandings and Future Directions. American journal of respiratory cell and molecular biology Zhao, L., Luo, J. L., Ali, M. K., Spiekerkoetter, E., Nicolls, M. R. 2022

    Abstract

    Microorganisms colonizing the human body. The lungs and respiratory tract, previously thought to be sterile, harbor diverse microbial communities and the genomes of bacteria (bacteriome), viruses (virome), and fungi (mycobiome). Recent advances in amplicon and shotgun metagenomic sequencing technologies, and data analyzing methods have greatly aided the identification and characterization of microbial populations from airways. The respiratory microbiome has been shown to play roles in human health and disease and is an area of rapidly emerging interest in pulmonary medicine. In this review we provide updated information in the field by focusing on four lung conditions including asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), and idiopathic pulmonary fibrosis (IPF). We evaluate gut, oral, and upper airway microbiomes, and how they contribute to lower airway flora. The discussion is followed by a systematic review of the lower airway microbiome in health and disease. We conclude with promising research avenues and implications for evolving therapeutics.

    View details for DOI 10.1165/rcmb.2022-0208TR

    View details for PubMedID 36476129

  • Biochemical, biophysical, and immunological characterization of respiratory secretions in severe SARS-CoV-2 infections. JCI insight Kratochvil, M. J., Kaber, G., Demirdjian, S., Cai, P. C., Burgener, E. B., Nagy, N., Barlow, G. L., Popescu, M., Nicolls, M. R., Ozawa, M. G., Regula, D. P., Pacheco-Navarro, A. E., Yang, S., de Jesus Perez, V. A., Karmouty-Quintana, H., Peters, A. M., Zhao, B., Buja, M. L., Johnson, P. Y., Vernon, R. B., Wight, T. N., Stanford COVID-19 Biobank Study Group, Milla, C. E., Rogers, A. J., Spakowitz, A. J., Heilshorn, S. C., Bollyky, P. L. 2022; 7 (12)

    Abstract

    Thick, viscous respiratory secretions are a major pathogenic feature of COVID-19, but the composition and physical properties of these secretions are poorly understood. We characterized the composition and rheological properties (i.e., resistance to flow) of respiratory secretions collected from intubated COVID-19 patients. We found the percentages of solids and protein content were greatly elevated in COVID-19 compared with heathy control samples and closely resembled levels seen in cystic fibrosis, a genetic disease known for thick, tenacious respiratory secretions. DNA and hyaluronan (HA) were major components of respiratory secretions in COVID-19 and were likewise abundant in cadaveric lung tissues from these patients. COVID-19 secretions exhibited heterogeneous rheological behaviors, with thicker samples showing increased sensitivity to DNase and hyaluronidase treatment. In histologic sections from these same patients, we observed increased accumulation of HA and the hyaladherin versican but reduced tumor necrosis factor-stimulated gene-6 staining, consistent with the inflammatory nature of these secretions. Finally, we observed diminished type I interferon and enhanced inflammatory cytokines in these secretions. Overall, our studies indicated that increases in HA and DNA in COVID-19 respiratory secretion samples correlated with enhanced inflammatory burden and suggested that DNA and HA may be viable therapeutic targets in COVID-19 infection.

    View details for DOI 10.1172/jci.insight.152629

    View details for PubMedID 35730564

  • Endogenous Retroviral Elements Generate Pathologic Neutrophils in Pulmonary Arterial Hypertension. American journal of respiratory and critical care medicine Taylor, S., Isobe, S., Cao, A., Contrepois, K., Benayoun, B. A., Jiang, L., Wang, L., Melemenidis, S., Ozen, M. O., Otsuki, S., Shinohara, T., Sweatt, A. J., Kaplan, J., Moonen, J., Marciano, D. P., Gu, M., Miyagawa, K., Hayes, B., Sierra, R. G., Kupitz, C. J., Del Rosario, P. A., Hsi, A., Thompson, A. A., Ariza, M. E., Demirci, U., Zamanian, R. T., Haddad, F., Nicolls, M. R., Snyder, M. P., Rabinovitch, M. 2022

    Abstract

    RATIONALE: The role of neutrophils and their extracellular vesicles (EVs) in the pathogenesis of pulmonary arterial hypertension is unclear.OBJECTIVES: Relate functional abnormalities in pulmonary arterial hypertension neutrophils and their EVs to mechanisms uncovered by proteomic and transcriptomic profiling.METHODS: Production of elastase, release of extracellular traps, adhesion and migration were assessed in neutrophils from pulmonary arterial hypertension patients and control subjects. Proteomic analyses were applied to explain functional perturbations, and transcriptomic data were used to find underlying mechanisms. CD66b-specific neutrophil EVs were isolated from plasma of patients with pulmonary arterial hypertension and we determined whether they produce pulmonary hypertension in mice.MEASUREMENTS AND MAIN RESULTS: Neutrophils from pulmonary arterial hypertension patients produce and release increased neutrophil elastase, associated with enhanced extracellular traps. They exhibit reduced migration and increased adhesion attributed to elevated beta1integrin and vinculin identified on proteomic analysis and previously linked to an antiviral response. This was substantiated by a transcriptomic interferon signature that we related to an increase in human endogenous retrovirus k envelope protein. Transfection of human endogenous retrovirus k envelope in a neutrophil cell line (HL-60) increases neutrophil elastase and interferon genes, whereas vinculin is increased by human endogenous retrovirus k dUTPase that is elevated in patient plasma. Neutrophil EVs from patient plasma contain increased neutrophil elastase and human endogenous retrovirus k envelope and induce pulmonary hypertension in mice, mitigated by elafin, an elastase inhibitor.CONCLUSIONS: Elevated human endogenous retroviral elements and elastase link a neutrophil innate immune response to pulmonary arterial hypertension.

    View details for DOI 10.1164/rccm.202102-0446OC

    View details for PubMedID 35696338

  • The role of circular RNAs in pulmonary hypertension. The European respiratory journal Ali, M. K., Schimmel, K., Zhao, L., Chen, C. K., Dua, K., Nicolls, M. R., Spiekerkoetter, E. 2022

    Abstract

    Circular RNAs (CircRNAs) are endogenous, covalently circularized, non-protein-coding RNAs generated from back splicing. Most circRNAs are very stable, highly conserved, and expressed in a tissue-, cell- and developmental stage-specific manner. CircRNAs play a significant role in various biological processes, such as regulation of gene expression and protein translation via sponging of microRNAs and binding with RNA binding proteins. CircRNAs have become a topic of great interest in research due to their close link with the development of various diseases. Their high stability, conservation, and abundance in body fluids make them promising biomarkers for many diseases. A growing body of evidence suggests that aberrant expression of circRNAs and their targets plays a crucial role in pulmonary vascular remodeling and Group 1 pulmonary arterial hypertension (PAH) as well as other forms of pulmonary hypertension (PH) (Group 3 and 4). Here we discuss the roles and molecular mechanisms of circRNAs in the pathogenesis of pulmonary vascular remodeling and PH. We also highlight the therapeutic and biomarker potential of circRNAs in PH.

    View details for DOI 10.1183/13993003.00012-2022

    View details for PubMedID 35680145

  • Overexpression of Pericyte HIF2 alpha Exacerbates Hypoxia Induced Pulmonary Hypertension and Right Ventricular Hypertrophy Kim, H., Liu, Y., Kim, J., Klouda, T., Hu, C., Tian, W., Jiang, X., Wu, J., Stenmark, K. R., Nicolls, M. R., De Jesus Perez, V., Raby, B. A., Yuan, K. AMER THORACIC SOC. 2022
  • Divergent Roles of Lymphatic Endothelial Cell-Expressed Hypoxia-Inducible Factors in Airway Transplant Rejection Mcquiston, A. S., Kim, D., Vihn, R., Schneider, E. C., Tian, W., Jiang, X., Nicolls, M. R. AMER THORACIC SOC. 2022
  • Single-Cell RNA-seq Reveals Transcriptionally Convergent Pulmonary Endothelial Cells in an Inflammatory Model of Pulmonary Arterial Hypertension with BMPR2 Dysfunction Kim, D., Zhao, L., Wu, T., Vihn, R., Schneider, E., Cunningham, C. M., Mcquiston, A. S., Kao, P. N., Jiang, X., Tian, A., Nicolls, M. R. AMER THORACIC SOC. 2022
  • CES1 Deficiency Is Associated with Oxidative Stress Mediated Endoplasmic Reticulum/Mitochondrial Dysfunction in Pulmonary Endothelial Cells Agarwal, S. S., Chakraborty, A., Shamskhou, E., Condon, D. F., Suresh, K., Rabinovitch, M., Nicolls, M. R., Perez, V. AMER THORACIC SOC. 2022
  • Biochemical, Biophysical, and Immunological Characterization of Respiratory Secretions in Severe SARS-CoV-2 (COVID-19) Infections. medRxiv : the preprint server for health sciences Kratochvil, M. J., Kaber, G., Demirdjian, S., Cai, P. C., Burgener, E. B., Nagy, N., Barlow, G. L., Popescu, M., Nicolls, M. R., Ozawa, M. G., Regula, D. P., Pacheco-Navarro, A. E., Yang, S., de Jesus Perez, V. A., Karmouty-Quintana, H., Peters, A. M., Zhao, B., Buja, M. L., Johnson, P. Y., Vernon, R. B., Wight, T. N., Stanford COVID-19 Biobank Study Group, Milla, C. E., Rogers, A. J., Spakowitz, A. J., Heilshorn, S. C., Bollyky, P. L. 2022

    Abstract

    Thick, viscous respiratory secretions are a major pathogenic feature of COVID-19 disease, but the composition and physical properties of these secretions are poorly understood. We characterized the composition and rheological properties (i.e. resistance to flow) of respiratory secretions collected from intubated COVID-19 patients. We find the percent solids and protein content are greatly elevated in COVID-19 compared to heathy control samples and closely resemble levels seen in cystic fibrosis, a genetic disease known for thick, tenacious respiratory secretions. DNA and hyaluronan (HA) are major components of respiratory secretions in COVID-19 and are likewise abundant in cadaveric lung tissues from these patients. COVID-19 secretions exhibit heterogeneous rheological behaviors with thicker samples showing increased sensitivity to DNase and hyaluronidase treatment. In histologic sections from these same patients, we observe increased accumulation of HA and the hyaladherin versican but reduced tumor necrosis factora"stimulated gene-6 (TSG6) staining, consistent with the inflammatory nature of these secretions. Finally, we observed diminished type I interferon and enhanced inflammatory cytokines in these secretions. Overall, our studies indicate that increases in HA and DNA in COVID-19 respiratory secretion samples correlate with enhanced inflammatory burden and suggest that DNA and HA may be viable therapeutic targets in COVID-19 infection.

    View details for DOI 10.1101/2022.03.28.22272848

    View details for PubMedID 35411348

  • Exploring disease interrelationships in patients with lymphatic disorders: A single center retrospective experience. Clinical and translational medicine Rockson, S. G., Zhou, X., Zhao, L., Hosseini, D. K., Jiang, X., Sweatt, A. J., Kim, D., Tian, W., Snyder, M. P., Nicolls, M. R. 2022; 12 (4): e760

    Abstract

    The lymphatic contribution to the circulation is of paramount importance in regulating fluid homeostasis, immune cell trafficking/activation and lipid metabolism. In comparison to the blood vasculature, the impact of the lymphatics has been underappreciated, both in health and disease, likely due to a less well-delineated anatomy and function. Emerging data suggest that lymphatic dysfunction can be pivotal in the initiation and development of a variety of diseases across broad organ systems. Understanding the clinical associations between lymphatic dysfunction and non-lymphatic morbidity provides valuable evidence for future investigations and may foster the discovery of novel biomarkers and therapies.We retrospectively analysed the electronic medical records of 724 patients referred to the Stanford Center for Lymphatic and Venous Disorders. Patients with an established lymphatic diagnosis were assigned to groups of secondary lymphoedema, lipoedema or primary lymphovascular disease. Individuals found to have no lymphatic disorder were served as the non-lymphatic controls. The prevalence of comorbid conditions was enumerated. Pairwise co-occurrence pattern analyses, validated by Jaccard similarity tests, was utilised to investigate disease-disease interrelationships.Comorbidity analyses underscored the expected relationship between the presence of secondary lymphoedema and those diseases that damage the lymphatics. Cardiovascular conditions were common in all lymphatic subgroups. Additionally, statistically significant alteration of disease-disease interrelationships was noted in all three lymphatic categories when compared to the control population.The presence or absence of a lymphatic disease significantly influences disease interrelationships in the study cohorts. As a physiologic substrate, the lymphatic circulation may be an underappreciated participant in disease pathogenesis. These relationships warrant further, prospective scrutiny and study.

    View details for DOI 10.1002/ctm2.760

    View details for PubMedID 35452183

  • Hypoxia and Hypoxia-Inducible Factors in Lymphedema. Frontiers in pharmacology Jiang, X., Tian, W., Kim, D., McQuiston, A. S., Vinh, R., Rockson, S. G., Semenza, G. L., Nicolls, M. R. 2022; 13: 851057

    Abstract

    Lymphedema is a chronic inflammatory disorder characterized by edema, fat deposition, and fibrotic tissue remodeling. Despite significant advances in lymphatic biology research, our knowledge of lymphedema pathology is incomplete. Currently, there is no approved pharmacological therapy for this debilitating disease. Hypoxia is a recognized feature of inflammation, obesity, and fibrosis. Understanding hypoxia-regulated pathways in lymphedema may provide new insights into the pathobiology of this chronic disorder and help develop new medicinal treatments.

    View details for DOI 10.3389/fphar.2022.851057

    View details for PubMedID 35450048

  • The COVID-19 Outpatient Pragmatic Platform Study (COPPS): Study design of a multi-center pragmatic platform trial. Contemporary clinical trials Bunning, B., Hedlin, H., Purington, N., Sundaram, V., Kapphahn, K., Weng, Y., Cunanan, K., Maldonado, Y., Singh, U., Khosla, C., O'Hara, R., Nicolls, M., Springman, E., Parsonnet, J., Rogers, A., Levitt, J., Desai, M. 2021: 106509

    Abstract

    More than 3000 clinical trials related to COVID-19 have been registered through clinicaltrials.gov. With so many trials, there is a risk that many will be inconclusive due to being underpowered or due to an inability to recruit patients. At academic medical centers, multiple trials are competing for the same resources; the success of one may come at the expense of another. The COVID-19 Outpatient Pragmatic Protocol Study (COPPS) is a flexible phase 2, multi-site, randomized, blinded trial based at Stanford University designed to overcome these issues by simultaneously evaluating multiple COVID-19 treatments in the outpatient setting in one common platform with shared controls. This approach reduces the overall number of patients required for statistical power, while improving the likelihood that any enrolled patient receives active treatment. The platform study has two main domains designed to evaluate COVID-19 treatments by assessing their ability to reduce viral shedding (Viral Domain), measured with self-collected nasal swabs, or improve clinical outcomes (Clinical Domain), measured through self-reported symptomology data. Data are collected on both domains for all participants enrolled. Participants are followed over a 28-day period. COPPS has the advantage of pragmatism created around its workflow that is also appealing to potential participants because of a lower probability of inactive treatment. At the conclusion of this clinical trial we expect to have identified potentially effective therapeutic strategy/ies for treating COVID-19 in the outpatient setting, which will have a transformative impact on medicine and public health.

    View details for DOI 10.1016/j.cct.2021.106509

    View details for PubMedID 34274494

  • The inflammatory role of dysregulated IRS2 in pulmonary vascular remodeling under hypoxic conditions. American journal of physiology. Lung cellular and molecular physiology Nakahara, M., Ito, H., Skinner, J. T., Lin, Q., Tamosiuniene, R., Nicolls, M. R., Keegan, A. D., Johns, R. A., Yamaji-Kegan, K. 2021

    Abstract

    Pulmonary hypertension (PH) is a devastating disease characterized by progressive elevation of pulmonary vascular resistance, right ventricular failure, and ultimately death. We have shown previously that insulin receptor substrate 2 (IRS2), a molecule highly critical to insulin resistance and metabolism, has an anti-inflammatory role in Th2-skewed lung inflammation and pulmonary vascular remodeling. Here, we investigated the hypothesis that IRS2 has an immunomodulatory role in human and experimental PH. Expression analysis showed that IRS2 was significantly decreased in the pulmonary vasculature of patients with pulmonary arterial hypertension and in rat models of PH. In mice, genetic ablation of IRS2 enhanced the hypoxia-induced signaling pathway of Akt and Forkhead box O1 (FOXO1) in the lung tissue and increased pulmonary vascular muscularization, proliferation, and perivascular macrophage recruitment. Furthermore, mice with homozygous IRS2 gene deletion showed a significant gene dosage-dependent increase in pulmonary vascular remodeling and right ventricular hypertrophy in response to hypoxia. Functional studies with bone marrow-derived macrophages isolated from homozygous IRS2 gene-deleted mice showed that hypoxia exposure led to enhancement of the Akt and ERK signaling pathway followed by increases in the pro-PH macrophage activation markers vascular endothelial growth factor-A and arginase 1. Our data suggest that IRS2 contributes to anti-inflammatory effects by regulating macrophage activation and recruitment, which may limit the vascular inflammation, remodeling, and right ventricular hypertrophy that are seen in PH pathology. Restoring the IRS2 pathway may be an effective therapeutic approach for the treatment of PH and right heart failure.

    View details for DOI 10.1152/ajplung.00068.2020

    View details for PubMedID 34189964

  • Reply to: Multiple Manifestations of Systemic Sclerosis Affect Walk Distance. American journal of respiratory and critical care medicine Zamanian, R. T., Pinckney, A., Domsic, R. T., Medsger, T., Keyes-Elstein, L., Sweatt, A. J., Welch, B., Goldmuntz, E., Nicolls, M. R., Chung, L., NIH ASC01 Study Group 2021

    View details for DOI 10.1164/rccm.202104-1023LE

    View details for PubMedID 34107229

  • The Kinetics of Lymphatic Dysfunction and Leukocyte Expansion in the Draining Lymph Node during LTB4 Antagonism in a Mouse Model of Lymphedema. International journal of molecular sciences Cribb, M. T., Sestito, L. F., Rockson, S. G., Nicolls, M. R., Thomas, S. N., Dixon, J. B. 2021; 22 (9)

    Abstract

    The mechanisms of lymphedema development are not well understood, but emerging evidence highlights the crucial role the immune system plays in driving its progression. It is well known that lymphatic function deteriorates as lymphedema progresses; however, the connection between this progressive loss of function and the immune-driven changes that characterize the disease has not been well established. In this study, we assess changes in leukocyte populations in lymph nodes within the lymphatic drainage basin of the tissue injury site (draining lymph nodes, dLNs) using a mouse tail model of lymphedema in which a pair of draining collecting vessels are left intact. We additionally quantify lymphatic pump function using established near infrared (NIR) lymphatic imaging methods and lymph-draining nanoparticles (NPs) synthesized and employed by our team for lymphatic tissue drug delivery applications to measure lymphatic transport to and resulting NP accumulation within dLNs associated with swelling following surgery. When applied to assess the effects of the anti-inflammatory drug bestatin, which has been previously shown to be a possible treatment for lymphedema, we find lymph-draining NP accumulation within dLNs and lymphatic function to increase as lymphedema progresses, but no significant effect on leukocyte populations in dLNs or tail swelling. These results suggest that ameliorating this loss of lymphatic function is not sufficient to reverse swelling in this surgically induced disease model that better recapitulates the extent of lymphatic injury seen in human lymphedema. It also suggests that loss of lymphatic function during lymphedema may be driven by immune-mediated mechanisms coordinated in dLNs. Our work indicates that addressing both lymphatic vessel dysfunction and immune cell expansion within dLNs may be required to prevent or reverse lymphedema when partial lymphatic function is sustained.

    View details for DOI 10.3390/ijms22094455

    View details for PubMedID 33923272

  • Safety and Efficacy of B-Cell Depletion with Rituximab for the Treatment of Systemic Sclerosis Associated Pulmonary Arterial Hypertension: A Multi-center, Double-blind, Randomized, Placebo-controlled Trial. American journal of respiratory and critical care medicine Zamanian, R. T., Badesch, D., Chung, L., Domsic, R. T., Medsger, T., Pinckney, A., Keyes-Elstein, L., D'Aveta, C., Spychala, M., White, R. J., Hassoun, P. M., Torres, F., Sweatt, A. J., Molitor, J. A., Khanna, D., Maecker, H., Welch, B., Goldmuntz, E., Nicolls, M. R., NIH ASC01 Study Group 2021

    Abstract

    RATIONALE: Systemic sclerosis-pulmonary arterial hypertension (SSc-PAH) is one of the most prevalent and deadly forms of PAH. B cells may contribute to SSc pathogenesis.OBJECTIVE: We investigated the safety and efficacy of B-cell depletion for SSc-PAH.METHODS AND MEASUREMENTS: In an NIH-sponsored, multi-center, double-blinded, randomized, placebo-controlled, proof-of-concept trial, 57 SSc-PAH patients on stable-dose standard medical therapy received two infusions of 1000 mg of rituximab or placebo administered two weeks apart. The primary outcome measure was the change in six-minute walk distance (6MWD) at 24 weeks. Secondary endpoints included safety and invasive hemodynamics. We applied a machine learning approach to predict drug-responsiveness.MAIN RESULTS: We randomized 57 subjects from 2010-2018. In the primary analysis, using data through week 24, the adjusted mean change in 6MWD at 24 weeks favored the treatment arm but did not reach statistical significance (23.6±11.1m vs. 0.5±9.7m, p=0.12). While a negative study, when data through week 48 were also considered, the estimated change in 6MWD at week 24 was 25.5±8.8m for rituximab and 0.4±7.4m for placebo (p=0.03). Rituximab treatment appeared to be safe and well tolerated. Low levels of rheumatoid factor (RF), IL-12, and IL-17 were sensitive and specific as favorable predictors of a rituximab response as measured by an improved 6MWD (ROC AUC 0.88-0.95).CONCLUSIONS: B cell depletion therapy is a potentially effective and safe adjuvant treatment for SSc-PAH. Future studies in these patients can confirm whether the identified biomarkers predict rituximab-responsiveness. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT01086540.

    View details for DOI 10.1164/rccm.202009-3481OC

    View details for PubMedID 33651671

  • Microvasculature in murine tracheal allografts after combined therapy with clopidogrel and everolimus. Interactive cardiovascular and thoracic surgery Heim, C., Kuckhahn, A., Ramsperger-Gleixner, M., Nicolls, M. R., Weyand, M., Ensminger, S. M. 2021

    Abstract

    OBJECTIVES: Survival after lung transplantation is mainly limited by the development of chronic lung allograft dysfunction. Previous studies have suggested T-cell mediated proliferation and microvascular changes in experimental small airways models as potential therapeutic targets. The aim of this study was to assess microvascular changes in murine orthotopic tracheal allografts after treatment with everolimus alone or in combination with clopidogrel.METHODS: C57Bl/6 (H-2b) donor tracheas were orthotopically transplanted into CBA (H-2k) recipients. Mice received daily injections of everolimus (0.05mg/kg) alone or combined with clopidogrel (1mg/kg). Twenty-eight days after transplantation, ratio of the thickness of tracheal epithelium and lamina propria was measured as an indicator for chronic rejection. Additionally, graft oxygenation and graft perfusion were detected on postoperative days 4, 10 and 28. Quantitative reverse transcription polymerase chain reaction analysis was used for gene expression analysis.RESULTS: While syngeneic grafts showed a stable tissue pO2 and undisturbed microvascular perfusion, rejecting allografts had a drastic decline in both parameters as well as a flattened epithelium and an increased thickness of the lamina propria. Treatment with everolimus reduced allogeneic fibroproliferation, but had no protective effects on the microvasculature; polymerase chain reaction analysis indicated hypoxic stress and inflammation. Combining everolimus with clopidogrel improved microvascular integrity in the tracheal grafts, but had no synergistic effect in preventing obliterative bronchiolitis development.CONCLUSIONS: These data demonstrate that the ability of everolimus to reduce the development of post-transplant obliterative bronchiolitis is not caused by microvascular protection and has no synergistic effects with clopidogrel in acute airway rejection.

    View details for DOI 10.1093/icvts/ivab021

    View details for PubMedID 33550369

  • The Role of Regulatory T Cells in Pulmonary Arterial Hypertension. Frontiers in immunology Tian, W., Jiang, S. Y., Jiang, X., Tamosiuniene, R., Kim, D., Guan, T., Arsalane, S., Pasupneti, S., Voelkel, N. F., Tang, Q., Nicolls, M. R. 2021; 12: 684657

    Abstract

    Pulmonary arterial hypertension (PAH) is a chronic, incurable condition characterized by pulmonary vascular remodeling, perivascular inflammation, and right heart failure. Regulatory T cells (Tregs) stave off autoimmunity, and there is increasing evidence for their compromised activity in the inflammatory milieu of PAH. Abnormal Treg function is strongly correlated with a predisposition to PAH in animals and patients. Athymic Treg-depleted rats treated with SU5416, an agent causing pulmonary vascular injury, develop PAH, which is prevented by infusing missing CD4+CD25highFOXP3+ Tregs. Abnormal Treg activity may also explain why PAH disproportionately affects women more than men. This mini review focuses on the role of Tregs in PAH with a special view to sexual dimorphism and the future promise of Treg therapy.

    View details for DOI 10.3389/fimmu.2021.684657

    View details for PubMedID 34489935

  • Colorectal Cancer-Associated Microbiome Patterns and Signatures. Frontiers in genetics Zhao, L., Cho, W. C., Nicolls, M. R. 1800; 12: 787176

    Abstract

    The gut microbiome is dynamic and shaped by diet, age, geography, and environment. The disruption of normal gut microbiota (dysbiosis) is closely related to colorectal cancer (CRC) risk and progression. To better identify and characterize CRC-associated dysbiosis, we collected six independent cohorts with matched normal pairs (when available) for comparison and exploration of the microbiota and their interactions with the host. Comparing the microbial community compositions between cancerous and adjacent noncancerous tissues, we found that more microbes were depleted than enriched in tumors. Despite taxonomic variations among cohorts, consistent depletion of normal microbiota (members of Clostridia and Bacteroidia) and significant enrichment of oral-originated pathogens (such as Fusobacterium nucleatum and Parvimonas micra) were observed in CRC compared to normal tissues. Sets of hub and hub-connecting microbes were subsequently identified to infer microbe-microbe interaction networks in CRC. Furthermore, biclustering was used for identifying coherent patterns between patients and microbes. Two patient-microbe interaction patterns, named P0 and P1, can be consistently identified among the investigated six CRC cohorts. Characterization of the microbial community composition of the two patterns revealed that patients in P0 and P1 differed significantly in microbial alpha and beta diversity, and CRC-associated microbiota changes consist of continuous populations of widespread taxa rather than discrete enterotypes. In contrast to the P0, the patients in P1 have reduced microbial alpha diversity compared to the adjacent normal tissues, and P1 possesses more oral-related pathogens than P0 and controls. Collectively, our study investigated the CRC-associated microbiome changes, and identified reproducible microbial signatures across multiple independent cohorts. More importantly, we revealed that the CRC heterogeneity can be partially attributed to the variety and compositional differences of microbes and their interactions to humans.

    View details for DOI 10.3389/fgene.2021.787176

    View details for PubMedID 35003221

  • Pulmonary Arterial Hypertension: Diagnosis, Treatment, and Novel Advances. American journal of respiratory and critical care medicine Maron, B. A., Abman, S. H., Elliott, C. G., Frantz, R. P., Hopper, R. K., Horn, E. M., Nicolls, M. R., Shlobin, O. A., Shah, S. J., Kovacs, G. n., Olschewski, H. n., Rosenzweig, E. B. 2021

    Abstract

    The diagnosis and management of pulmonary arterial hypertension (PAH) includes several advances, such as broader recognition of extra-pulmonary vascular organ system involvement, validated point-of-care clinical assessment tools, and a focus on early-initiation of multiple pharmacotherapeutics in appropriate patients. Indeed, a principal goal in PAH today is early diagnosis for prompt initiation of treatment to achieve minimal symptom burden, optimize the patient's biochemical, hemodynamic, and functional profile, and limit adverse events. To accomplish this end, clinicians must be familiar with novel risk factors and the revised hemodynamic definition for PAH. Fresh insights into the role of developmental biology (i.e., perinatal health) may also be useful for predicting incident PAH in early adulthood. Emergent or underutilized approaches to PAH management include a novel TGF-β ligand trap pharmacotherapy, remote pulmonary artery pressure monitoring, next-generation imaging using inert gas-based magnetic resonance and other technologies, right atrial pacing, and pulmonary artery denervation. These and other PAH state-of-the-art advances are summarized here for the wider pulmonary medicine community.

    View details for DOI 10.1164/rccm.202012-4317SO

    View details for PubMedID 33861689

  • Donor-derived, cell-free DNA levels by next-generation targeted sequencing are elevated in allograft rejection after lung transplantation. ERJ open research Khush, K. K., De Vlaminck, I., Luikart, H., Ross, D. J., Nicolls, M. R. 2021; 7 (1)

    Abstract

    Surveillance after lung transplantation is critical to the detection of acute cellular rejection (ACR) and prevention of chronic lung allograft dysfunction (CLAD). Therefore, we measured donor-derived cell-free DNA (dd-cfDNA) implementing a clinical-grade, next-generation targeted sequencing assay in 107 plasma samples from 38 unique lung transplantation recipients with diagnostic cohorts classified as: (1) biopsy-confirmed or treated ACR, (2) antibody-mediated rejection (AMR), (3) obstructive CLAD, (4) allograft infection (INFXN) and (5) Stable healthy allografts (STABLE). Our principal findings are as follows: (1) dd-cfDNA level was elevated in ACR (median 0.91%; interquartile range (IQR): 0.39-2.07%), CLAD (2.06%; IQR: 0.57-3.67%) and an aggregated cohort of rejection encompassing allograft injury (1.06%; IQR: 0.38-2.51%), compared with the STABLE cohort (0.38%; IQR: 0.23-0.87%) (p=0.02); (2) dd-cfDNA level with AMR was elevated (1.34%; IQR: 0.34-2.40%) compared to STABLE, although it did not reach statistical significance (p=0.07) due to limitations in sample size; (3) there was no difference in dd-cfDNA for allograft INFXN (0.39%; IQR: 0.18-0.67%) versus STABLE, which may relate to differences in "tissue injury" with the spectrum of bronchial colonisation versus invasive infection; (4) there was no difference for dd-cfDNA in unilateral versus bilateral lung transplantation; (5) "optimal threshold" for dd-cfDNA for aggregated rejection events representing allograft injury was determined as 0.85%, with sensitivity=55.6%, specificity=75.8%, positive predictive value (PPV)=43.3% and negative predictive value (NPV)=83.6%. Measurement of plasma dd-cfDNA may be a clinically useful tool for the assessment of lung allograft health and surveillance for "tissue injury" with a spectrum of rejection.

    View details for DOI 10.1183/23120541.00462-2020

    View details for PubMedID 33532456

  • Severe Pulmonary Arterial Hypertension is Characterized by Increased Neutrophil Elastase and Relative Elafin Deficiency. Chest Sweatt, A. J., Miyagawa, K., Rhodes, C. J., Taylor, S., Del Rosario, P. A., Hsi, A., Haddad, F., Spiekerkoetter, E., Bental-Roof, M., Bland, R. D., Swietlik, E. M., Gräf, S., Wilkins, M. R., Morrell, N. W., Nicolls, M. R., Rabinovitch, M., Zamanian, R. T. 2021

    Abstract

    Preclinical evidence implicates neutrophil elastase (NE) in PAH pathogenesis, and the NE inhibitor elafin is under early therapeutic investigation.Are circulating NE and elafin levels abnormal in PAH and associated with clinical severity?. In an observational Stanford University PAH cohort (N=249), plasma NE and elafin were measured in comparison to healthy controls (N=106) then related to clinical features and relevant ancillary biomarkers. Cox regression models were fitted with cubic spline functions to associate NE and elafin with survival. To validate prognostic relationships, we analyzed two United Kingdom cohorts (N=75, N=357). Mixed effects models evaluated NE and elafin changes during disease progression. Finally, we studied effects of NE/elafin balance on pulmonary artery endothelial cells (PAECs) from PAH patients.Relative to controls, patients had increased NE (205.1 [123.6-387.3] vs. 97.6 [74.4-126.6] ng/mL, P<0.0001) and decreased elafin (32.0 [15.3-59.1] vs. 45.5 [28.1-92.8] ng/mL, P<0.0001) independent of PAH subtype, illness duration, and therapies. Higher NE associated with worse symptom severity, shorter six-minute walk distance, higher NT-proBNP, greater right ventricular dysfunction, worse hemodynamics, increased circulating neutrophils, elevated cytokine levels, and lower blood BMPR2 expression. In Stanford patients, NE>168.5 ng/mL portended increased mortality risk after adjustment for known clinical predictors (HR 2.52, CI 1.36-4.65, P=0.003) or prognostic cytokines (HR 2.63, CI 1.42-4.87, P=0.001), and NE added incremental value to established PAH risk scores. Similar prognostic thresholds were identified in validation cohorts. Longitudinal NE changes tracked with clinical trends and outcomes. PAH-PAECs exhibited increased apoptosis and attenuated angiogenesis when exposed to NE at the level observed in patients' blood. Elafin rescued PAEC homeostasis, yet the required dose exceeded levels found in patients.NE is increased and elafin deficient across PAH subtypes. NE associates with disease severity and outcomes, and this target-specific biomarker could facilitate therapeutic development of elafin.

    View details for DOI 10.1016/j.chest.2021.06.028

    View details for PubMedID 34181952

  • Leukotrienes in Tumor-Associated Inflammation. Frontiers in pharmacology Tian, W., Jiang, X., Kim, D., Guan, T., Nicolls, M. R., Rockson, S. G. 2020; 11: 1289

    Abstract

    Leukotrienes are biologically active eicosanoid lipid mediators that originate from oxidative metabolism of arachidonic acid. Biosynthesis of leukotrienes involves a set of soluble and membrane-bound enzymes that constitute a machinery complex primarily expressed by cells of myeloid origin. Leukotrienes and their synthetic enzymes are critical immune modulators for leukocyte migration. Increased concentrations of leukotrienes are implicated in a number of inflammatory disorders. More recent work indicates that leukotrienes may also interact with a variety of tissue cells, contributing to the low-grade inflammation of cardiovascular, neurodegenerative, and metabolic conditions, as well as that of cancer. Leukotriene signaling contributes to the active tumor microenvironment, promoting tumor growth and resistance to immunotherapy. This review summarizes recent insights into the intricate roles of leukotrienes in promoting tumor growth and metastasis through shaping the tumor microenvironment. The emerging possibilities for pharmacological targeting of leukotriene signaling in tumor metastasis are considered.

    View details for DOI 10.3389/fphar.2020.01289

    View details for PubMedID 32973519

    View details for PubMedCentralID PMC7466732

  • Leukotrienes in Tumor-Associated Inflammation FRONTIERS IN PHARMACOLOGY Tian, W., Jiang, X., Kim, D., Guan, T., Nicolls, M. R., Rockson, S. G. 2020; 11
  • Endothelial HIF-2alpha as a Key Endogenous Mediator Preventing Emphysema. American journal of respiratory and critical care medicine Pasupneti, S., Tian, W., Tu, A. B., Dahms, P., Granucci, E., Gandjeva, A., Xiang, M., Butcher, E., Semenza, G. L., Tuder, R., Jiang, X., Nicolls, M. R. 2020

    Abstract

    RATIONALE: Endothelial injury may provoke emphysema, but molecular pathways of disease development require further discernment. Emphysema lungs exhibit decreased expression of hypoxia inducible factor-2alpha (HIF-2alpha)-regulated genes, and tobacco smoke decreases pulmonary HIF-2alpha levels. These findings suggest that decreased HIF-2alpha expression is important in the development of emphysema.OBJECTIVES: The objective of this study was to evaluate the roles of endothelial cell (EC) HIF-2alpha in the pathogenesis of emphysema in mice.METHODS: Mouse lungs were examined for emphysema following either the loss or overexpression of EC Hif-2alpha. Additionally, SU5416, a VEGFR2 inhibitor, was used to induce emphysema. Lungs were evaluated for hepatocyte growth factor (HGF), a protein involved in alveolar development and homeostasis. Patient emphysema lungs were measured for endothelial HIF-2alpha expression.MEASUREMENTS AND MAIN RESULTS: EC Hif-2alpha deletion resulted in emphysema, in association with fewer ECs and pericytes. Following SU5416 exposure, EC Hif-2alpha knockout mice developed more severe emphysema, whereas EC Hif-2alpha-overexpressing mice were protected. EC Hif-2alpha knockout mice demonstrated lower levels of HGF. Human emphysema lung samples exhibited reduced EC HIF-2alpha expression.CONCLUSIONS: Here, we demonstrate a unique, protective role for pulmonary endothelial HIF-2alpha and how decreased expression of this endogenous factor causes emphysema; its pivotal protective function is suggested by its ability to overcome VEGF antagonism. HIF-2alpha may maintain alveolar architecture by promoting vascular survival and associated HGF production. In summary, HIF-2alpha may be a key endogenous factor that prevents the development of emphysema, and its upregulation has the potential to foster lung health in at-risk patients.

    View details for DOI 10.1164/rccm.202001-0078OC

    View details for PubMedID 32515984

  • The Hallmarks of Severe Pulmonary Arterial Hypertension: The Cancer Hypothesis - Ten years later. American journal of physiology. Lung cellular and molecular physiology Cool, C. D., Kuebler, W. M., Bogaard, H. J., Spiekerkoetter, E., Nicolls, M. R., Voelkel, N. F. 2020

    Abstract

    Severe forms of pulmonary arterial hypertension (PAH) are most frequently the consequence of a lumen-obliterating angiopathy. One pathobiological model is, that the initial pulmonary vascular endothelial cell injury and apoptosis is followed by the evolution of phenotypically altered, apoptosis-resistant, proliferating cells and an inflammatory vascular immune response. Although there may be a vasoconstrictive disease component, the increased pulmonary vascular shear stress in established PAH is caused largely by the vascular wall pathology. In this review, we revisit the "quasi-malignancy concept" of severe PAH and examine to what extent the hallmarks of PAH can be compared to the hallmarks of cancer. The cancer model of severe PAH, based on the growth of abnormal vascular and bone marrow-derived cells, may enable the emergence of novel cell-based PAH treatment strategies.

    View details for DOI 10.1152/ajplung.00476.2019

    View details for PubMedID 32023082

  • Decreased lymphatic HIF-2α accentuates lymphatic remodeling in lymphedema. The Journal of clinical investigation Jiang, X. n., Tian, W. n., Granucci, E. J., Tu, A. B., Kim, D. n., Dahms, P. n., Pasupneti, S. n., Peng, G. n., Kim, Y. n., Lim, A. H., Espinoza, F. H., Cribb, M. n., Dixon, J. B., Rockson, S. G., Semenza, G. L., Nicolls, M. R. 2020

    Abstract

    Pathologic lymphatic remodeling in lymphedema evolves during periods of tissue inflammation and hypoxia through poorly defined processes. In human and mouse lymphedema, there is a significant increase of hypoxia inducible factor (HIF)-1α, but a reduction of HIF-2α protein expression in lymphatic endothelial cells (LECs). We questioned whether dysregulated expression of these transcription factors contributes to disease pathogenesis and found that LEC-specific deletion of Hif-2α exacerbated lymphedema pathology. Even without lymphatic vascular injury, the loss of LEC-specific Hif-2α caused anatomic pathology and a functional decline in fetal and adult mice. These findings suggest that HIF-2α is an important mediator of lymphatic health. HIF-2α promoted protective phosphorylated TIE2 (p-TIE2) signaling in LECs, a process also replicated by upregulating TIE2 signaling through adenovirus-mediated angiopoietin-1 (Angpt1) gene therapy. Our study suggests that HIF-2α normally promotes healthy lymphatic homeostasis and raises the exciting possibility that restoring HIF-2α pathways in lymphedema could mitigate long-term pathology and disability.

    View details for DOI 10.1172/JCI136164

    View details for PubMedID 32673288

  • From 2D to 3D: Promising Advances in Imaging Lung Structure. Frontiers in medicine Klouda, T. n., Condon, D. n., Hao, Y. n., Tian, W. n., Lvova, M. n., Chakraborty, A. n., Nicolls, M. R., Zhou, X. n., Raby, B. A., Yuan, K. n. 2020; 7: 343

    Abstract

    The delicate structure of murine lungs poses many challenges for acquiring high-quality images that truly represent the living lung. Here, we describe several optimized procedures for obtaining and imaging murine lung tissue. Compared to traditional paraffin cross-section and optimal cutting temperature (OCT), agarose-inflated vibratome sections (aka precision-cut lung slices), combines comparable structural preservation with experimental flexibility. In particular, we discuss an optimized procedure to precision-cut lung slices that can be used to visualize three-dimensional cell-cell interactions beyond the limitations of two-dimensional imaging. Super-resolution microscopy can then be used to reveal the fine structure of lung tissue's cellular bodies and processes that regular confocal cannot. Lastly, we evaluate the entire lung vasculature with clearing technology that allows imaging of the entire volume of the lung without sectioning. In this manuscript, we combine the above procedures to create a novel and evolutionary method to study cell behavior ex vivo, trace and reconstruct pulmonary vasculature, address fundamental questions relevant to a wide variety of vascular disorders, and perceive implications to better imaging clinical tissue.

    View details for DOI 10.3389/fmed.2020.00343

    View details for PubMedID 32766264

    View details for PubMedCentralID PMC7381109

  • Mural Cell SDF1 Signaling is Associated with the Pathogenesis of Pulmonary Arterial Hypertension. American journal of respiratory cell and molecular biology Yuan, K. n., Liu, Y. n., Zhang, Y. n., Nathan, A. n., Tian, W. n., Yu, J. n., Sweatt, A. J., Condon, D. n., Chakraborty, A. n., Agarwal, S. n., Auer, N. n., Zhang, S. n., Wu, J. C., Zamanian, R. T., Nicolls, M. R., de Jesus Perez, V. A. 2020

    Abstract

    Pulmonary artery smooth muscle cells (PASMCs) and pericytes are NG2+ mural cells that provide structural support to pulmonary arteries and capillaries. In pulmonary arterial hypertension (PAH), both mural cell types contribute to PA muscularization but whether similar mechanisms are responsible for their behavior is unknown.RNA-Seq was used to compare the gene profile of pericytes and PASMCs from PAH and healthy lungs. NG2-Cre-ER mice were used to generate NG2-selective reporter mice (NG2tdT) for cell lineage identification and tamoxifen-inducible mice for NG2-selective SDF1 knockout (SDF1NG2-KO).Hierarchical clustering of RNA-seq data demonstrated that the genetic profile of PAH pericytes and PASMCs is highly similar. Cellular lineage staining studies on NG2tdT mice in chronic hypoxia showed that similar to PAH, tdT+ cells accumulate in muscularized microvessels and demonstrate significant upregulation of SDF1, a chemokine involved in chemotaxis and angiogenesis. Compared to controls, SDF1NG2-KO mice in chronic hypoxia had reduced muscularization and lower abundance of NG2+ cells around microvessels. SDF1 stimulation in healthy pericytes induced greater contractility and impaired their capacity to establish endothelial-pericyte communications. In contrast, SDF1 knockdown reduced PAH pericyte contractility and improved their capacity to associate with vascular tubes in co-culture.SDF1 is upregulated in NG2+ mural cells and is associated with PA muscularization. Targeting SDF1 could help prevent and/or reverse muscularization in PAH.

    View details for DOI 10.1165/rcmb.2019-0401OC

    View details for PubMedID 32084325

  • Machine learning algorithms to differentiate among pulmonary complications after hematopoietic cell transplant. Chest Sharifi, H. n., Lai, Y. K., Guo, H. n., Hoppenfeld, M. n., Guenther, Z. D., Johnston, L. n., Brondstetter, T. n., Chhatwani, L. n., Nicolls, M. R., Hsu, J. L. 2020

    Abstract

    Pulmonary complications, including infections, are highly prevalent in patients after hematopoietic cell transplant with chronic graft-versus-host disease. These comorbid diseases can make the diagnosis of early lung graft-versus-host disease (bronchiolitis obliterans syndrome) challenging. A quantitative method to differentiate among these pulmonary diseases can address diagnostic challenges and facilitate earlier and more targeted therapy.We conducted a single center study of 66 patients with computed tomography chest scans analyzed with a quantitative imaging tool known as parametric response mapping. Parametric response mapping results were correlated with pulmonary function tests and clinical characteristics. Five parametric response mapping metrics were applied to K-means clustering and support vector machine models to distinguish among post-transplant lung complications solely from quantitative output.Compared to parametric response mapping, spirometry showed a moderate correlation with radiographic air trapping, and total lung capacity and residual volume showed a strong correlation with radiographic lung volumes. K-means clustering analysis distinguished 4 unique clusters. Clusters 2 and 3 represented obstructive physiology (encompassing 81% of patients with bronchiolitis obliterans syndrome) in increasing severity (percent air trapping 15.6% and 43.0%, respectively). Cluster 1 was dominated by normal lung, and cluster 4 was characterized by patients with parenchymal opacities. A support vector machine algorithm differentiated bronchiolitis obliterans syndrome with specificity of 88%, sensitivity of 83%, accuracy of 86% and an area under the receiver operating characteristic curve of 0.85.Our machine learning models offer a quantitative approach for the identification of bronchiolitis obliterans syndrome versus other lung diseases, including late pulmonary complications after hematopoietic cell transplant.

    View details for DOI 10.1016/j.chest.2020.02.076

    View details for PubMedID 32343962

  • IPSE, an abundant egg-secreted protein of the carcinogenic helminth Schistosoma haematobium, promotes proliferation of bladder cancer cells and angiogenesis. Infectious agents and cancer Mbanefo, E. C., Agbo, C. T., Zhao, Y., Lamanna, O. K., Thai, K. H., Karinshak, S. E., Khan, M. A., Fu, C., Odegaard, J. I., Saltikova, I. V., Smout, M. J., Pennington, L. F., Nicolls, M. R., Jardetzky, T. S., Loukas, A., Brindley, P. J., Falcone, F. H., Hsieh, M. H. 2020; 15: 63

    Abstract

    Background: Schistosoma haematobium, the helminth causing urogenital schistosomiasis, is a known bladder carcinogen. Despite the causal link between S. haematobium and bladder cancer, the underlying mechanisms are poorly understood. S. haematobium oviposition in the bladder is associated with angiogenesis and urothelial hyperplasia. These changes may be pre-carcinogenic events in the bladder. We hypothesized that the Interleukin-4-inducing principle of Schistosoma mansoni eggs (IPSE), an S. haematobium egg-secreted "infiltrin" protein that enters host cell nuclei to alter cellular activity, is sufficient to induce angiogenesis and urothelial hyperplasia. Methods: Mouse bladders injected with S. haematobium eggs were analyzed via microscopy for angiogenesis and urothelial hyperplasia. Endothelial and urothelial cell lines were incubated with recombinant IPSE protein or an IPSE mutant protein that lacks the native nuclear localization sequence (NLS-) and proliferation measured using CFSE staining and real-time monitoring of cell growth. IPSE's effects on urothelial cell cycle status was assayed through propidium iodide staining. Endothelial and urothelial cell uptake of fluorophore-labeled IPSE was measured. Findings: Injection of S. haematobium eggs into the bladder triggers angiogenesis, enhances leakiness of bladder blood vessels, and drives urothelial hyperplasia. Wild type IPSE, but not NLS-, increases proliferation of endothelial and urothelial cells and skews urothelial cells towards S phase. Finally, IPSE is internalized by both endothelial and urothelial cells. Interpretation: IPSE drives endothelial and urothelial proliferation, which may depend on internalization of the molecule. The urothelial effects of IPSE depend upon its NLS. Thus, IPSE is a candidate pro-carcinogenic molecule of S. haematobium.Summary: Schistosoma haematobium acts as a bladder carcinogen through unclear mechanisms. The S. haematobium homolog of IPSE, a secreted schistosome egg immunomodulatory molecule, enhances angiogenesis and urothelial proliferation, hallmarks of pre-carcinogenesis, suggesting IPSE is a key pro-oncogenic molecule of S. haematobium.

    View details for DOI 10.1186/s13027-020-00331-6

    View details for PubMedID 33101456

  • Bone Morphogenetic Protein Receptor 2 Mutations Impair T Regulatory Cell Function and Promote Inflammation in Pulmonary Arterial Hypertension Peng, G., Tian, A., Guan, T., Wu, T., Nicolls, M. R. AMER THORACIC SOC. 2020
  • Single-Cell RNA-seq Analysis Reveals Endothelial Heterogeneity of Inflammation-Induced Pulmonary Arterial Hypertension Under Bmpr2 Dysfunction Wu, T., Peng, G., Tian, A., Guan, T., Nicolls, M. R. AMER THORACIC SOC. 2020
  • Safety and Efficacy of B-cell Depletion with Rituximab for the Treatment of Systemic Sclerosis-associated Pulmonary Arterial Hypertension in a Multi-center NIH Clinical Trial Nicolls, M., Badesch, D., Chung, L., Domsic, R., Medsger, T., Pinckney, A., Keyes-Elstein, L., D'Aveta, C., Spychala, M., White, R., Hassoun, P., Torres, F., Molitor, J., Khanna, D., Maeker, H., Welch, B., Goldmuntz, E., Zamanian, R., ASC01 Investigators WILEY. 2019
  • Late Breaking Abstract - Safety and efficacy of B-cell depletion with rituximab for the treatment of systemic sclerosis-associated pulmonary arterial hypertension Zamanian, R., Badesch, D., Chung, L., Domsic, R., Medsger, T., Pinckney, A., Keyes-Elstein, L., D'Aveta, C., Spychala, M., White, J., Hassoun, P., Torres, F., Molitor, J., Khanna, D., Maeker, H., Welch, B., Goldmuntz, E., Nicolls, M., Asco1 Investigators EUROPEAN RESPIRATORY SOC JOURNALS LTD. 2019
  • Preservation of Microvascular Integrity in Murine Orthotopic Tracheal Allografts by Clopidogrel TRANSPLANTATION Heim, C., Khan, M., von Silva-Tarouca, B., Kuckhahn, A., Stamminger, T., Ramsperger-Gleixner, M., Nicolls, M. R., Weyand, M., Ensminger, S. M. 2019; 103 (5): 899–908
  • Inducible expression of immediate early genes is regulated through dynamic chromatin association by NF45/ILF2 and NF90/NF110/ILF3 PLOS ONE Wu, T., Shi, L., Lowe, A. W., Nicolls, M. R., Kao, P. N. 2019; 14 (4)
  • Loss of Endothelium-Derived Wnt5a Is Associated With Reduced Pericyte Recruitment and Small Vessel Loss in Pulmonary Arterial Hypertension CIRCULATION Yuan, K., Shamskhou, E. A., Orcholski, M. E., Nathan, A., Reddy, S., Honda, H., Mani, V., Zeng, Y., Ozen, M. O., Wang, L., Demirci, U., Tian, W., Nicolls, M. R., Perez, V. 2019; 139 (14): 1710–24
  • Discovery of Distinct Immune Phenotypes Using Machine Learning in Pulmonary Arterial Hypertension CIRCULATION RESEARCH Sweatt, A. J., Hedlin, H. K., Balasubramanian, V., Hsi, A., Blum, L. K., Robinson, W. H., Haddad, F., Hickey, P. M., Condliffe, R., Lawrie, A., Nicolls, M. R., Rabinovitch, M., Khatri, P., Zamanian, R. T. 2019; 124 (6): 904–19
  • Preservation of microvascular integrity in murine orthotopic tracheal allografts by clopidogrel. Transplantation Heim, C., Khan, M. A., Silva-Tarouca, B. v., Kuckhahn, A., Stamminger, T., Ramsperger-Gleixner, M., Nicolls, M. R., Weyand, M., Ensminger, S. M. 2019

    Abstract

    BACKGROUND: Survival after lung transplantation is mainly limited by the development of chronic lung allograft dysfunction (CLAD). The aim of this study was to investigate if platelet inhibition by clopidogrel has a functionally relevant influence on the microvascular integrity of orthotopic tracheal allografts as an anatomic basis for the development of CLAD.METHODS: We orthotopically transplanted C57Bl/6 (H-2) tracheas into CBA.J (H-2) recipients which afterwards received clopidogrel (1mg/kg). Morphometric analysis was performed by measuring epithelial height in proportion to thickness of the lamina propria (ELR). Tissue oxygenation was determined using a fluorescence quenching technique and graft perfusion monitoring was performed by Laser Doppler Flowmetry and lectin-binding assay. Immunohistochemistry was used for detection of CD31 and iNOS while iron deposition was shown with Prussian blue reaction. Quantitative RT-PCR analysis was used for gene expression analysis.RESULTS: Isografts maintained good oxygenation and perfusion throughout the experiment, while both were drastically reduced in allografts. Treatment with clopidogrel attenuated graft hypoxia and reduced loss of perfusion. Additionally, clopidogrel led to increased ELR while iron deposition was impaired. Gene expression analysis revealed elevated levels of angiogenic VEGF in the clopidogrel group. Improved endothelial function shown by immunohistochemistry (CD31, iNOS).CONCLUSIONS: Continuous administration of clopidogrel significantly improved tissue oxygenation, limited microvascular leakiness, and prevented airway ischemia. These data demonstrate that clopidogrel ameliorates microvascular injury during acute airway rejection which is a known predisposing factor for the development of CLAD.

    View details for PubMedID 30801550

  • Anti-hyperlipidaemic effects of synthetic analogues of nordihydroguaiaretic acid in dyslipidaemic rats BRITISH JOURNAL OF PHARMACOLOGY Singh, M., Bittner, S., Li, Y., Bittner, A., Han, L., Cortez, Y., Inayathullah, M., Arif, Z., Parthasarathi, R., Rajadas, J., Shen, W., Nicolls, M. R., Kraemer, F. B., Azhar, S. 2019; 176 (3): 369–85

    View details for DOI 10.1111/bph.14528

    View details for Web of Science ID 000455517100003

  • Airway hypoxia in lung transplantation CURRENT OPINION IN PHYSIOLOGY Pasupneti, S., Nicolls, M. R. 2019; 7: 21–26
  • Endothelial Hypoxia-Inducible Factor-2 Is Required for the Maintenance of Airway Microvasculature CIRCULATION Jiang, X., Tian, W., Tu, A. B., Pasupneti, S., Shuffle, E., Dahms, P., Zhang, P., Cai, H., Dinh, T. T., Liu, B., Cain, C., Giaccia, A. J., Butcher, E. C., Simon, M., Semenza, G. L., Nicolls, M. R. 2019; 139 (4): 502-517
  • The Lymphatic System in Obesity, Insulin Resistance, and Cardiovascular Diseases. Frontiers in physiology Jiang, X. n., Tian, W. n., Nicolls, M. R., Rockson, S. G. 2019; 10: 1402

    Abstract

    Obesity, insulin resistance, dyslipidemia, and hypertension are fundamental clinical manifestations of the metabolic syndrome. Studies over the last few decades have implicated chronic inflammation and microvascular remodeling in the development of obesity and insulin resistance. Newer observations, however, suggest that dysregulation of the lymphatic system underlies the development of the metabolic syndrome. This review summarizes recent advances in the field, discussing how lymphatic abnormality promotes obesity and insulin resistance, and, conversely, how the metabolic syndrome impairs lymphatic function. We also discuss lymphatic biology in metabolically dysregulated diseases, including type 2 diabetes, atherosclerosis, and myocardial infarction.

    View details for DOI 10.3389/fphys.2019.01402

    View details for PubMedID 31798464

    View details for PubMedCentralID PMC6868002

  • Pathology and pathobiology of pulmonary hypertension: state of the art and research perspectives Humbert, M., Guignabert, C., Bonnet, S., Dorfmuller, P., Klinger, J. R., Nicolls, M. R., Olschewski, A. J., Pullamsetti, S. S., Schermuly, R. T., Stenmark, K. R., Rabinovitch, M. EUROPEAN RESPIRATORY SOC JOURNALS LTD. 2019
  • Inducible expression of immediate early genes is regulated through dynamic chromatin association by NF45/ILF2 and NF90/NF110/ILF3. PloS one Wu, T. H., Shi, L. n., Lowe, A. W., Nicolls, M. R., Kao, P. N. 2019; 14 (4): e0216042

    Abstract

    Immediate early gene (IEG) transcription is rapidly activated by diverse stimuli. This transcriptional regulation is assumed to involve constitutively expressed nuclear factors that are targets of signaling cascades initiated at the cell membrane. NF45 (encoded by ILF2) and its heterodimeric partner NF90/NF110 (encoded by ILF3) are chromatin-interacting proteins that are constitutively expressed and localized predominantly in the nucleus. Previously, NF90/NF110 chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) in K562 erythroleukemia cells revealed its enriched association with chromatin at active promoters and strong enhancers. NF90/NF110 specifically occupied the promoters of IEGs. Here, ChIP in serum-starved HEK293 cells demonstrated that NF45 and NF90/NF110 pre-exist and specifically occupy the promoters of IEG transcription factors EGR1, FOS and JUN. Cellular stimulation with phorbol myristyl acetate increased NF90/NF110 chromatin association, while decreasing NF45 chromatin association at promoters of EGR1, FOS and JUN. In HEK293 cells stably transfected with doxycycline-inducible shRNA vectors targeting NF90/NF110 or NF45, doxycycline-mediated knockdown of NF90/NF110 or NF45 attenuated the inducible expression of EGR1, FOS, and JUN at the levels of transcription, RNA and protein. Dynamic chromatin association of NF45 and NF90/NF110 at IEG promoters are observed upon stimulation, and NF45 and NF90/NF110 contribute to inducible transcription of IEGs. NF45 and NF90/NF110 operate as chromatin regulators of the immediate early response.

    View details for PubMedID 31022259

  • Phenotypically-Silent Bone Morphogenetic Protein Receptor 2 (Bmpr2) Mutations Predispose Rats to Inflammation-Induced Pulmonary Arterial Hypertension by Enhancing The Risk for Neointimal Transformation. Circulation Tian, W. n., Jiang, X. n., Sung, Y. K., Shuffle, E. n., Wu, T. H., Kao, P. N., Tu, A. B., Dorfmüller, P. n., Cao, A. n., Wang, L. n., Peng, G. n., Kim, Y. n., Zhang, P. n., Chappell, J. n., Pasupneti, S. n., Dahms, P. n., Maguire, P. n., Chaib, H. n., Zamanian, R. n., Peters-Golden, M. n., Snyder, M. P., Voelkel, N. F., Humbert, M. n., Rabinovitch, M. n., Nicolls, M. R. 2019

    Abstract

    Bmpr2 mutations are critical risk factors for hereditary pulmonary arterial hypertension (hPAH) with approximately 20% of carriers developing disease. There is an unmet medical need to understand how environmental factors, such as inflammation, render Bmpr2 mutants susceptible to PAH. Overexpressing 5-lipoxygenase (5-LO) provokes lung inflammation and transient PAH in Bmpr2+/- mice. Accordingly, 5-LO and its metabolite, leukotriene B4 (LTB4), are candidates for the 'second hit'. The purpose of this study was to determine how 5-LO-mediated pulmonary inflammation synergized with phenotypically-silent Bmpr2 defects to elicit significant pulmonary vascular disease in rats.Monoallelic Bmpr2 mutant rats were generated and found phenotypically normal for up to one year of observation. To evaluate whether a second hit would elicit disease, animals were exposed to 5-LO-expressing adenovirus (AdAlox5), monocrotaline, SU5416, SU5416 with chronic hypoxia or chronic hypoxia alone. Bmpr2-mutant hPAH patient samples were assessed for neointimal 5-LO expression. Pulmonary artery endothelial cells (PAECs) with impaired BMPR2 signaling were exposed to increased 5-LO-mediated inflammation and were assessed for phenotypic and transcriptomic changes.Lung inflammation, induced by intratracheal delivery of AdAlox5, elicited severe PAH with intimal remodeling in Bmpr2+/- rats but not in their wild-type littermates. Neointimal lesions in the diseased Bmpr2+/- rats gained endogenous 5-LO expression associated with elevated LTB4 biosynthesis. Bmpr2-mutant hPAH patients similarly expressed 5-LO in the neointimal cells. In vitro, BMPR2 deficiency, compounded by 5-LO-mediated inflammation, generated apoptosis-resistant, and proliferative PAECs with mesenchymal characteristics. These transformed cells expressed nuclear envelope-localized 5-LO consistent with induced LTB4 production, as well as a transcriptomic signature similar to clinical disease, including upregulated NF-κB, IL-6, and TGF-β signaling pathways. The reversal of PAH and vasculopathy in Bmpr2 mutants by TGF-β antagonism suggests that TGF-β is critical for neointimal transformation.In a new 'two-hit' model of disease, lung inflammation induced severe PAH pathology in Bmpr2+/- rats. Endothelial transformation required the activation of canonical and noncanonical TGF-β signaling pathways and was characterized by 5-LO nuclear envelope translocation with enhanced LTB4 production. This study offers one explanation of how an environmental injury unleashes the destructive potential of an otherwise-silent genetic mutation.

    View details for DOI 10.1161/CIRCULATIONAHA.119.040629

    View details for PubMedID 31462075

  • Discovery of Distinct Immune Phenotypes Using Machine Learning in Pulmonary Arterial Hypertension. Circulation research Sweatt, A. J., Hedlin, H. K., Balasubramanian, V. n., Hsi, A. n., Blum, L. K., Robinson, W. H., Haddad, F. n., Hickey, P. M., Condliffe, R. A., Lawrie, A. n., Nicolls, M. R., Rabinovitch, M. n., Khatri, P. n., Zamanian, R. T. 2019

    Abstract

    Accumulating evidence implicates inflammation in pulmonary arterial hypertension (PAH) and therapies targeting immunity are under investigation, though it remains unknown if distinct immune phenotypes exist.Identify PAH immune phenotypes based on unsupervised analysis of blood proteomic profiles.In a prospective observational study of Group 1 PAH patients evaluated at Stanford University (discovery cohort, n=281) and University of Sheffield (validation cohort, n=104) between 2008-2014, we measured a circulating proteomic panel of 48 cytokines, chemokines, and factors using multiplex immunoassay. Unsupervised machine learning (consensus clustering) was applied in both cohorts independently to classify patients into proteomic immune clusters, without guidance from clinical features. To identify central proteins in each cluster, we performed partial correlation network analysis. Clinical characteristics and outcomes were subsequently compared across clusters. Four PAH clusters with distinct proteomic immune profiles were identified in the discovery cohort. Cluster 2 (n=109) had low cytokine levels similar to controls. Other clusters had unique sets of upregulated proteins central to immune networks- cluster 1 (n=58)(TRAIL, CCL5, CCL7, CCL4, MIF), cluster 3 (n=77)(IL-12, IL-17, IL-10, IL-7, VEGF), and cluster 4 (n=37)(IL-8, IL-4, PDGF-β, IL-6, CCL11). Demographics, PAH etiologies, comorbidities, and medications were similar across clusters. Non-invasive and hemodynamic surrogates of clinical risk identified cluster 1 as high-risk and cluster 3 as low-risk groups. Five-year transplant-free survival rates were unfavorable for cluster 1 (47.6%, CI 35.4-64.1%) and favorable for cluster 3 (82.4%, CI 72.0-94.3%)(across-cluster p<0.001). Findings were replicated in the validation cohort, where machine learning classified four immune clusters with comparable proteomic, clinical, and prognostic features.Blood cytokine profiles distinguish PAH immune phenotypes with differing clinical risk that are independent of World Health Organization Group 1 subtypes. These phenotypes could inform mechanistic studies of disease pathobiology and provide a framework to examine patient responses to emerging therapies targeting immunity.

    View details for PubMedID 30661465

  • High Dose Ubenimex Interferes with the Efficacy of Sildenafil in Experimental Pulmonary Hypertension Dahms, P., Tian, A., Zhang, P., Tu, A. B., Jiang, X., Pasupneti, S., Peng, G., Nicolls, M. R. AMER THORACIC SOC. 2019
  • The Role of Iron-Induced Macrophage Dysregulation in Aspergillus Fumigatus Invasion in Airway Transplantation Matthaiou, E., Manouvakhova, O. M., Sinha, M., Tu, A. B., Clemons, K. V., Stevens, D. A., Nicolls, M. R., Hsu, J. L. AMER THORACIC SOC. 2019
  • HIF1 alpha-Mediated Lymphangiogenesis Influences Airway Transplant Rejection Tu, A. B., Jiang, X., Tian, A., Dahms, P., Zhang, P., Pasupneti, S., Nicolls, M. R. AMER THORACIC SOC. 2019
  • Pilot studies demonstrate the potential benefits of antiinflammatory therapy in human lymphedema JCI INSIGHT Rockson, S. G., Tian, W., Jiang, X., Kuznetsova, T., Haddad, F., Zampell, J., Mehrara, B., Sampson, J. P., Roche, L., Kim, J., Nicolls, M. R. 2018; 3 (20)
  • Endothelial HIF-2alpha is Required for the Maintenance of Airway Microvasculature. Circulation Jiang, X., Tian, W., Tu, A. B., Pasupneti, S., Shuffle, E., Dahms, P., Zhang, P., Cai, H., Dinh, T. T., Liu, B., Cain, C., Giaccia, A. J., Butcher, E. C., Simon, C., Semenza, G. L., Nicolls, M. R. 2018

    Abstract

    BACKGROUND: Hypoxia-inducible factors (HIFs), especially HIF-1alpha and HIF-2alpha, are key mediators of the adaptive response to hypoxic stress and play essential roles in maintaining lung homeostasis. Human and animal genetics studies confirm that abnormal HIF correlates with pulmonary vascular pathology and chronic lung diseases, but it remains unclear whether endothelial cell (EC) HIF production is essential for microvascular health. The large airway has an ideal circulatory bed for evaluating histologic changes and physiology in genetically-modified rodents.METHODS: The tracheal microvasculature of mice, with conditionally-deleted or overexpressed HIF-1alpha or HIF-2alpha, was evaluated for anatomy, perfusion, and permeability. Angiogenic signaling studies assessed vascular changes attributable to dysregulated HIF expression. An orthotopic tracheal transplantation model further evaluated the contribution of individual HIF isoforms in airway ECs.RESULTS: The genetic deletion of Hif-2alpha, but not Hif-1alpha, caused tracheal EC apoptosis, diminished pericyte coverage, reduced vascular perfusion, defective barrier function, overlying epithelial abnormalities and subepithelial fibrotic remodeling. HIF-2alpha promoted microvascular integrity in airways through endothelial angiopoietin-1/TIE2 signaling and Notch activity. In functional tracheal transplants, HIF-2alpha deficiency in airway donors accelerated graft microvascular loss, whereas HIF-2alpha or angiopoietin-1 overexpression prolonged transplant microvascular perfusion. Augmented endothelial HIF-2alpha in transplant donors promoted airway microvascular integrity and diminished alloimmune inflammation.CONCLUSIONS: Our findings reveal that the constitutive expression of endothelial HIF-2alpha is required for airway microvascular health.

    View details for PubMedID 30586708

  • Dominant Role for Regulatory T Cells in Protecting Females Against Pulmonary Hypertension CIRCULATION RESEARCH Tamosiuniene, R., Manouvakhova, O., Mesange, P., Saito, T., Qian, J., Sanyal, M., Lin, Y., Nguyen, L. P., Luria, A., Tu, A. B., Sante, J. M., Rabinovitch, M., Fitzgerald, D. J., Graham, B. B., Habtezion, A., Voelkel, N. F., Aurelian, L., Nicolls, M. R. 2018; 122 (12): 1689-1702
  • Circulating plasmablasts are elevated and produce pathogenic anti-endothelial cell autoantibodies in idiopathic pulmonary arterial hypertension EUROPEAN JOURNAL OF IMMUNOLOGY Blum, L. K., Cao, R. L., Sweatt, A. J., Bill, M., Lahey, L. J., Hsi, A. C., Lee, C. S., Kongpachith, S., Ju, C., Mao, R., Wong, H. H., Nicolls, M. R., Zamanian, R. T., Robinson, W. H. 2018; 48 (5): 874–84
  • Circulating plasmablasts are elevated and produce pathogenic anti-endothelial cell autoantibodies in idiopathic pulmonary arterial hypertension. European journal of immunology Blum, L. K., Cao, R. R., Sweatt, A. J., Bill, M. n., Lahey, L. J., Hsi, A. C., Lee, C. S., Kongpachith, S. n., Ju, C. H., Mao, R. n., Wong, H. H., Nicolls, M. R., Zamanian, R. T., Robinson, W. H. 2018

    Abstract

    Idiopathic pulmonary arterial hypertension (IPAH) is a devastating pulmonary vascular disease in which autoimmune and inflammatory phenomena are implicated. B cells and autoantibodies have been associated with IPAH and identified as potential therapeutic targets. However, the specific populations of B cells involved and their roles in disease pathogenesis are not clearly defined. We aimed to assess the levels of activated B cells (plasmablasts) in IPAH, and to characterize recombinant antibodies derived from these plasmablasts. Blood plasmablasts are elevated in IPAH, remain elevated over time, and produce IgA autoantibodies. Single-cell sequencing of plasmablasts in IPAH revealed repertoires of affinity-matured antibodies with small clonal expansions, consistent with an ongoing autoimmune response. Recombinant antibodies representative of these clonal lineages bound known autoantigen targets and displayed an unexpectedly high degree of polyreactivity. Representative IPAH plasmablast recombinant antibodies stimulated human umbilical vein endothelial cells to produce cytokines and overexpress the adhesion molecule ICAM-1. Together, our results demonstrate an ongoing adaptive autoimmune response involving IgA plasmablasts that produce anti-endothelial cell autoantibodies in IPAH. These antibodies stimulate endothelial cell production of cytokines and adhesion molecules, which may contribute to disease pathogenesis. These findings suggest a role for mucosally-driven autoimmunity and autoimmune injury in the pathogenesis of IPAH. This article is protected by copyright. All rights reserved.

    View details for PubMedID 29369345

  • Loss of Endothelial Derived WNT5A is Associated with Reduced Pericyte Recruitment and Small Vessel Loss in Pulmonary Arterial Hypertension. Circulation Yuan, K. n., Shamskhou, E. A., Orcholski, M. E., Nathan, A. n., Reddy, S. n., Honda, H. n., Mani, V. n., Zeng, Y. n., Ozen, M. O., Wang, L. n., Demirci, U. n., Tian, W. n., Nicolls, M. R., de Jesus Perez, V. A. 2018

    Abstract

    Pulmonary arterial hypertension (PAH) is a life-threatening disorder of the pulmonary circulation associated with loss and impaired regeneration of microvessels. Reduced pericyte coverage of pulmonary microvessels is a pathological feature of PAH and is partly due to the inability of pericytes to respond to signaling cues from neighboring pulmonary microvascular endothelial cells (PMVECs). We have shown that activation of the Wnt/PCP pathway is required for pericyte recruitment but whether production and release of specific Wnt ligands by PMVECs is responsible for Wnt/PCP activation in pericytes is unknown.Isolation of pericytes and PMVECs from healthy donor and PAH lungs was carried out using 3G5 or CD31 antibody conjugated magnetic beads. Wnt expression profile of PMVECs was documented via qPCR using a Wnt primer library. Exosome purification from PMVEC media was carried out using the ExoTIC device. Hemodynamic profile, right ventricular function and pulmonary vascular morphometry were obtained in a conditional endothelial specific Wnt5a knockout ( Wnt5aECKO) mouse model under normoxia, chronic hypoxia and hypoxia recovery.Quantification of Wnt ligand expression in healthy PMVECs co-cultured with pericytes demonstrated a 35-fold increase in Wnt5a, a known Wnt/PCP ligand. This Wnt5a spike was not seen in PAH PMVECs, which correlated with inability to recruit pericytes in matrigel co-culture assays. Exosomes purified from media demonstrated an increase in Wnt5a content when healthy PMVECs were co-cultured with pericytes, a finding that was not observed in exosomes of PAH PMVECs. Furthermore, the addition of either recombinant Wnt5a or purified healthy PMVEC exosomes increased pericyte recruitment to PAH PMVECs in co-culture studies. While no differences were noted in normoxia and chronic hypoxia, Wnt5aECKO mice demonstrated persistent pulmonary hypertension and right ventricular failure four weeks after recovery from chronic hypoxia, which correlated with significant reduction, muscularization and decreased pericyte coverage of microvessels.We identify Wnt5a as a key mediator for the establishment of pulmonary endothelial-pericyte interactions and its loss could contribute to PAH by reducing the viability of newly formed vessels. We speculate that therapies that mimic or restore Wnt5a production could help prevent loss of small vessels in PAH.

    View details for PubMedID 30586764

  • Pilot studies demonstrate the potential benefits of antiinflammatory therapy in human lymphedema. JCI insight Rockson, S. G., Tian, W. n., Jiang, X. n., Kuznetsova, T. n., Haddad, F. n., Zampell, J. n., Mehrara, B. n., Sampson, J. P., Roche, L. n., Kim, J. n., Nicolls, M. R. 2018; 3 (20)

    Abstract

    Lymphedema is a common condition affecting millions around the world that still lacks approved medical therapy. Because ketoprofen, an NSAID, has been therapeutic in experimental lymphedema, we evaluated its efficacy in humans.We first performed an exploratory open-label trial. Patients with either primary or secondary lymphedema received ketoprofen 75 mg by mouth 3 times daily for 4 months. Subjects were evaluated for changes in histopathology, with skin thickness, limb volume, and tissue bioimpedance changes serving as secondary endpoints. Based on our encouraging findings, we next conducted a placebo-controlled trial, with the primary outcome defined as a change in skin thickness, as measured by skin calipers. Secondary endpoints for this second study included histopathology, limb volume, bioimpedance, and systemic inflammatory mediators.We enrolled 21 lymphedema patients in the open-label trial, from November 2010 to July 2011. Histopathology and skin thickness were significantly improved at 4 months compared with baseline. In the follow-up, double-blind, placebo-controlled trial, we enrolled 34 patients from August 2011 to October 2015, with 16 ketoprofen recipients and 18 placebo-treated subjects. No serious adverse events occurred. The ketoprofen recipients demonstrated reduced skin thickness, as well as improved composite measures of histopathology and decreased plasma granulocyte CSF (G-CSF) expression.These 2 exploratory studies together support the utility of targeted antiinflammatory therapy with ketoprofen in patients with lymphedema. Our results highlight the promise of such approaches to help restore a failing lymphatic circulation.ClinicalTrials.gov NCT02257970.

    View details for PubMedID 30333315

  • Increased Lymphangiogenesis in Animal Models of Pulmonary Arterial Hypertension Zhang, P., Tian, A. W., Tu, A. B., Jiang, X., Nicolls, M. R. AMER THORACIC SOC. 2018
  • Endothelial HIF-2 alpha Maintains Airway Microvasculature Through Angiopoietin-1/TIE2 Signaling Tu, A., Jiang, X., Tian, W., Nicolls, M. R. AMER THORACIC SOC. 2018
  • The Role of Hypoxia Inducible Factors in Maintenance of Airway Epithelial Health Pasupneti, S., Tian, A., Jiang, X., Nicolls, M. R. AMER THORACIC SOC. 2018
  • Pathology and pathobiology of pulmonary hypertension: state of the art and research perspectives. The European respiratory journal Humbert, M. n., Guignabert, C. n., Bonnet, S. n., Dorfmüller, P. n., Klinger, J. R., Nicolls, M. R., Olschewski, A. J., Pullamsetti, S. S., Schermuly, R. T., Stenmark, K. R., Rabinovitch, M. n. 2018

    Abstract

    Clinical and translational research has played a major role in advancing our understanding of pulmonary hypertension (PH), including pulmonary arterial hypertension and other forms of PH with severe vascular remodelling (e.g. chronic thromboembolic PH and pulmonary veno-occlusive disease). However, PH remains an incurable condition with a high mortality rate, underscoring the need for a better transfer of novel scientific knowledge into healthcare interventions. Herein, we review recent findings in pathology (with the questioning of the strict morphological categorisation of various forms of PH into pre- or post-capillary involvement of pulmonary vessels) and cellular mechanisms contributing to the onset and progression of pulmonary vascular remodelling associated with various forms of PH. We also discuss ways to improve management and to support and optimise drug development in this research field.

    View details for PubMedID 30545970

  • A Dominant Role for Regulatory T Cells in Protecting Females Against Pulmonary Hypertension. Circulation research Tamosiuniene, R. n., Manouvakhova, O. n., Mesange, P. n., Saito, T. n., Qian, J. n., Sanyal, M. n., Lin, Y. C., Nguyen, L. P., Luria, A. n., Tu, A. B., Sante, J. M., Rabinovitch, M. n., Fitzgerald, D. J., Graham, B. B., Habtezion, A. n., Voelkel, N. F., Aurelian, L. n., Nicolls, M. R. 2018

    Abstract

    Rationale: Pulmonary arterial hypertension (PH) is a life-threatening condition associated with immune dysregulation and abnormal regulatory T cell (Treg) activity, but it is currently unknown whether and how abnormal Treg function differentially affects males and females. Objective: To evaluate whether and how Treg-deficiency differentially affects male and female rats in experimental PH. Methods and Results: Male and female athymicrnu/rnurats, lacking Tregs, were treated with the vascular endothelial growth factor receptor-2 (VEGFR2) inhibitor SU5416 or chronic hypoxia and evaluated for PH; some animals underwent Treg immune reconstitution (IR) before SU5416 administration. Plasma prostacyclin (PGI2) levels were measured. Lung and right ventricles (RVs) were assessed for the expression of the vasoprotective proteins cyclooxygenase-2 (COX-2), prostacyclin synthase (PTGIS), programmed death ligand-1 (PDL-1), and heme oxygenase-1 (HO-1). Inhibitors of these pathways were administered to athymic rats undergoing Treg IR. Finally, human cardiac microvascular endothelial cells co-cultured with Tregs were evaluated for COX-2, PDL-1, HO-1, and estrogen receptor (ER) expression, and culture supernatants were assayed for PGI2 and IL-10. SU5416-treatment and chronic hypoxia produced more severe PH in female than male athymic rats. Females were distinguished by greater pulmonary inflammation, augmented RV fibrosis, lower plasma PGI2 levels, decreased lung COX-2, PTGIS, HO-1 and PDL-1 expression and reduced RV PDL-1 levels. In both sexes, Treg IR protected against PH development and raised levels of plasma PGI2 and cardiopulmonary COX-2, PTGIS, PDL-1, and HO-1. Inhibiting COX-2, HO-1, and programmed death-1 (PD1)/PDL1 pathways abrogated Treg protection. In vitro, human Tregs directly upregulated endothelial COX-2, PDL1, HO-1, ERs and increased supernatant levels of PGI2 and IL-10. Conclusions: In two animal models of PH based on Treg deficiency, females developed more severe PH than males. The data suggest that females are especially reliant on normal Treg function to counteract the effects of pulmonary vascular injury leading to PH.

    View details for PubMedID 29545367

  • Microhemorrhage-associated tissue iron enhances the risk forAspergillus fumigatusinvasion in a mouse model of airway transplantation. Science translational medicine Hsu, J. L., Manouvakhova, O. V., Clemons, K. V., Inayathullah, M. n., Tu, A. B., Sobel, R. A., Tian, A. n., Nazik, H. n., Pothineni, V. R., Pasupneti, S. n., Jiang, X. n., Dhillon, G. S., Bedi, H. n., Rajadas, J. n., Haas, H. n., Aurelian, L. n., Stevens, D. A., Nicolls, M. R. 2018; 10 (429)

    Abstract

    Invasive pulmonary disease due to the moldAspergillus fumigatuscan be life-threatening in lung transplant recipients, but the risk factors remain poorly understood. To study this process, we used a tracheal allograft mouse model that recapitulates large airway changes observed in patients undergoing lung transplantation. We report that microhemorrhage-related iron content may be a major determinant ofA. fumigatusinvasion and, consequently, its virulence. Invasive growth was increased during progressive alloimmune-mediated graft rejection associated with high concentrations of ferric iron in the graft. The role of iron inA. fumigatusinvasive growth was further confirmed by showing that this invasive phenotype was increased in tracheal transplants from donor mice lacking the hemochromatosis gene (Hfe -/- ). The invasive phenotype was also increased in mouse syngrafts treated with topical iron solution and in allograft recipients receiving deferoxamine, a chelator that increases iron bioavailability to the mold. The invasive growth of the iron-intolerantA. fumigatusdouble-knockout mutant (ΔsreA/ΔcccA) was lower than that of the wild-type mold. Alloimmune-mediated microvascular damage and iron overload did not appear to impair the host's immune response. In human lung transplant recipients, positive staining for iron in lung transplant tissue was more commonly seen in endobronchial biopsy sections from transplanted airways than in biopsies from the patients' own airways. Collectively, these data identify iron as a major determinant ofA. fumigatusinvasive growth and a potential target to treat or preventA. fumigatusinfections in lung transplant patients.

    View details for PubMedID 29467298

  • Nordihydroguaiaretic acid, a lignan from Larrea tridentata (Creosote bush) protects against ALIOS diet-induced metabolic dysfunction in mice. The Journal of pharmacology and experimental therapeutics Chan, J. K., Bittner, S. n., Bittner, A. n., Atwal, S. n., Shen, W. J., Inayathullah, M. n., Rajada, J. n., Nicolls, M. R., Kraemer, F. B., Azhar, S. n. 2018

    Abstract

    To determine the effects of NDGA on metabolic and molecular changes in response to feeding mice typical American fast food or Western diet, mice were fed with ALIOS diet and subjected to metabolic analysis. Male C57BL/6J mice were randomly assigned to: ALIOS, ALIOS + NDGA, or control diet and maintained on the specific diet for 8 weeks. Mice fed ALIOS diet, showed increased body, liver and epididymal fat pad weight, plasma ALT and AST levels (a measure of liver injury), and liver triglyceride (TG) content. Co-administration of NDGA normalized body and epididymal fat pad weight, ALT and AST levels, and liver TG. NDGA treatment also improved insulin sensitivity but not glucose intolerance in ALIOS diet fed mice. In ALIOS diet fed mice, NDGA supplementation induced PPARα (the master regulator of fatty acid oxidation) and mRNA levels of Cpt1c and Cpt2, key genes involved in fatty acid oxidation as compared to ALIOS diet. NDGA significantly reduced liver ER stress response CHOP protein, as compared to chow or ALIOS diet and also ameliorated ALIOS diet-induced elevation of apoptosis signaling protein, CASP3. Likewise, NDGA downregulated the ALIOS-diet induced mRNA levels of Pparg, Fasn, and Dgat2. NDGA treatment of ALIOS fed mice upregulated the hepatic expression of antioxidant enzymes, GPX4 and PRDX3 proteins. In conclusion, we provide evidence that NDGA improves metabolic dysregulation by simultaneously modulating PPARα transcription factor and key genes involved in fatty acid oxidation, key antioxidant and lipogenic enzymes, and apoptosis and ER stress signaling pathways.

    View details for PubMedID 29472517

  • A Pro - Con debate: Current Controversies in PAH Pathogenesis at the American Thoracic Society International Meeting in 2017. American journal of physiology. Lung cellular and molecular physiology Kuebler, W. M., Nicolls, M. R., Olschewski, A. n., Abe, K. n., Rabinovitch, M. n., Stewart, D. J., Chan, S. Y., Morrell, N. W., Archer, S. L., Spiekerkoetter, E. n. 2018

    Abstract

    The following review summarizes the pro-con debate about current controversies regarding the pathogenesis of pulmonary arterial hypertension (PAH) that took place at the American Thoracic Society Conference in May 2017. Leaders in the field of PAH research discussed the importance of the immune system, the role of hemodynamic stress and endothelial apoptosis as well as bone morphogenetic protein receptor 2 (BMPR2) signaling in PAH pathogenesis. While this summary does not intend to resolve obvious conflicts in opinion, we hope that the presented arguments entice further discussions and draw a new generation of enthusiastic researchers into this vibrant field of science to bridge existing gaps for a better understanding and therapy of this fatal disease.

    View details for PubMedID 29877097

  • Dynamics of the human antibody repertoire after B cell depletion in systemic sclerosis. Science immunology de Bourcy, C. F., Dekker, C. L., Davis, M. M., Nicolls, M. R., Quake, S. R. 2017; 2 (15)

    Abstract

    Systemic sclerosis with pulmonary arterial hypertension (SSc-PAH) is a debilitating and frequently lethal disease of unknown cause lacking effective treatment options. Lymphocyte anomalies and autoantibodies observed in systemic sclerosis have suggested an autoimmune character. We study the clonal structure of the B cell repertoire in SSc-PAH using immunoglobulin heavy chain (IGH) sequencing before and after B cell depletion. We found SSc-PAH to be associated with anomalies in B cell development, namely, altered VDJ rearrangement frequencies (reduced IGHV2-5 segment usage) and an increased somatic mutation-fixation probability in expanded B cell lineages. SSc-PAH was also characterized by anomalies in B cell homeostasis, namely, an expanded immunoglobulin D-positive (IgD(+)) proportion with reduced mutation loads and an expanded proportion of highly antibody-secreting cells. Disease signatures pertaining to IGHV2-5 segment usage, IgD proportions, and mutation loads were temporarily reversed after B cell depletion. Analyzing the time course of B cell depletion, we find that the kinetics of naïve replenishment are predictable from baseline measurements alone, that release of plasma cells into the periphery can precede naïve replenishment, and that modes of B cell receptor diversity are highly elastic. Our findings reveal humoral immune signatures of SSc-PAH and uncover determinism in the effects of B cell depletion on the antibody repertoire.

    View details for DOI 10.1126/sciimmunol.aan8289

    View details for PubMedID 28963118

  • Dynamics of the human antibody repertoire after B cell depletion in systemic sclerosis SCIENCE IMMUNOLOGY de Bourcy, C. A., Dekker, C. L., Davis, M. M., Nicolls, M. R., Quake, S. R. 2017; 2 (15)
  • The Roles of Immunity in the Prevention and Evolution of Pulmonary Arterial Hypertension AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE Nicolls, M. R., Voelkel, N. F. 2017; 195 (10): 1292-1299

    Abstract

    This Perspective provides an in depth overview of the many aspects of inflammation which are associated with many forms of severe pulmonary hypertension.Details of the pathobiology of severe pulmonary hypertension are discussed in the context of the multicellular inflammatory vascular infiltrates which represent a lung vessel response to injury and and a localized immune response.The important question whether inflammation is cause or consequence of pulmonary hypertension should not distract from designing and conducting clinical pilot studies which examine the efficacy of existing immune system modulating drugs.

    View details for DOI 10.1164/rccm.201608-1630PP

    View details for Web of Science ID 000401501400008

  • Leukotriene B-4 antagonism ameliorates experimental lymphedema SCIENCE TRANSLATIONAL MEDICINE Tian, W., Rockson, S. G., Jiang, X., Kim, J., Begaye, A., Shuffle, E. M., Tu, A. B., Cribb, M., Nepiyushchikh, Z., Feroze, A. H., Zamanian, R. T., Dhillon, G. S., Voelkel, N. F., Peters-Golden, M., Kitajewski, J., Dixon, J. B., Nicolls, M. R. 2017; 9 (389)
  • Simultaneously Targeting Myofibroblast Contractility and Extracellular Matrix Cross-Linking as a Therapeutic Concept in Airway Fibrosis AMERICAN JOURNAL OF TRANSPLANTATION Lin, Y., Sung, Y. K., Jiang, X., Peters-Golden, M., Nicolls, M. R. 2017; 17 (5): 1229-1241

    Abstract

    Fibrosis after solid organ transplantation is considered an irreversible process and remains the major cause of graft dysfunction and death with limited therapies. This remodeling is characterized by aberrant accumulation of contractile myofibroblasts that deposit excessive extracellular matrix (ECM) and increase tissue stiffness. However, studies demonstrate that a stiff ECM, itself, promotes fibroblast-to-myofibroblast differentiation, stimulating further ECM production. This creates a positive feedback loop that perpetuates fibrosis. We hypothesized that simultaneously targeting myofibroblast contractility with relaxin and ECM stiffness with lysyl oxidase inhibitors could break the feedback loop, thereby, reversing established fibrosis. To test this, we used the orthotopic tracheal transplanted (OTT) mouse model, which develops robust fibrotic airway remodeling. Mice with established fibrosis were treated with saline, mono-, or combination therapies. While monotherapies had no effect, combining these agents decreased collagen deposition and promoted re-epithelialization of remodeled airways. Relaxin inhibited myofibroblast differentiation and contraction, in a matrix-stiffness-dependent manner through prostaglandin E2 (PGE2 ). Furthermore, the effect of combination therapy was lost in PGE2 receptor knockout and PGE2 inhibited OTT mice. This study reveals the important synergistic roles of cellular contractility and tissue stiffness in the maintenance of fibrotic tissue and suggests a new therapeutic principle for fibrosis. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1111/ajt.14103

    View details for Web of Science ID 000400382300012

  • Microvascular Integrity Can Be Preserved by Anti-Platelet Therapy and in Combination with mTOR Inhibitor Heim, C., Khan, M. A., Motsch, B., Gocht, A., Ramsperger-Gleixner, M., Stamminger, T., Nicolls, M. R., Weyand, M., Ensminger, S. M. ELSEVIER SCIENCE INC. 2017: S376
  • Donor-Derived Cell-Free DNA Associates with Rejection in Lung Transplantation Using Clinical-Grade Targeted Next-Generation Sequencing Khush, K. K., Beausang, J. F., Woodward, R. N., Lew, D., Sninsky, J., De Vlaminck, I., Strehl, C., Luikart, H., Nicolls, M., Weill, D. ELSEVIER SCIENCE INC. 2017: S146
  • Translating Research into Improved Patient Care in Pulmonary Arterial Hypertension AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE Bonnet, S., Provencher, S., Guignabert, C., Perros, F., Boucherat, O., Schermuly, R. T., Hassoun, P. M., Rabinovitch, M., Nicolls, M. R., Humbert, M. 2017; 195 (5): 583-595

    Abstract

    Despite important advances in its therapeutic management, pulmonary arterial hypertension (PAH) remains an incurable disease. Although numerous drugs exhibited beneficial effects in preclinical settings, only few have reached clinical trial phases, highlighting the challenges of translating preclinical investigations into clinical trials. Potential reasons for delayed PAH drug development may include the inherent limitations of the currently available animal and in vitro models, potential lack of appropriate standardization of the experimental design, regulatory agencies requirements, competing clinical trials and insufficient funding. Although this is not unique to PAH, there is urgency for reducing the number of false positive signals in preclinical studies and optimizing the development of innovative therapeutic targets through performance of clinical trials based on more robust experimental data. The current review discusses the challenges and opportunities in preclinical research to foster drug development in PAH.

    View details for DOI 10.1164/rccm.201607-1515PP

    View details for Web of Science ID 000395357400008

  • Upregulation of HERV-K is Linked to Immunity and Inflammation in Pulmonary Arterial Hypertension. Circulation Saito, T. n., Miyagawa, K. n., Chen, S. Y., Tamosiuniene, R. n., Wang, L. n., Sharp, O. n., Samayoa, E. n., Harada, D. n., Moonen, J. A., Cao, A. n., Chen, P. I., Hennigs, J. K., Gu, M. n., Li, C. G., Leib, R. D., Li, D. n., Adams, C. M., Del Rosario, P. A., Bill, M. A., Haddad, F. n., Montoya, J. G., Robinson, W. n., Fantl, W. J., Nolan, G. P., Zamanian, R. T., Nicolls, M. R., Chiu, C. Y., Ariza, M. E., Rabinovitch, M. n. 2017

    Abstract

    Background -Immune dysregulation has been linked to occlusive vascular remodeling in pulmonary arterial hypertension (PAH) that is hereditary, idiopathic or associated with other conditions. Circulating autoantibodies, lung perivascular lymphoid tissue and elevated cytokines have been related to PAH pathogenesis but without clear understanding of how these abnormalities are initiated, perpetuated and connected in the progression of disease. We therefore set out to identify specific target antigens in PAH lung immune complexes as a starting point toward resolving these issues to better inform future application of immunomodulatory therapies. Methods -Lung immune complexes were isolated and PAH target antigens were identified by liquid chromatography tandem mass spectrometry (LCMS), confirmed by ELISA, and localized by confocal microscopy. One PAH antigen linked to immunity and inflammation was pursued and a link to PAH pathophysiology was investigated by next generation sequencing, functional studies in cultured monocytes and endothelial cells (EC) and hemodynamic and lung studies in a rat. Results -SAM domain and HD1 domain-containing protein (SAMHD1), an innate immune factor that suppresses HIV replication was identified and confirmed as highly expressed in immune complexes from 16 hereditary and idiopathic PAH vs. 12 control lungs. Elevated SAMHD1 was localized to endothelial cells (EC), perivascular dendritic cells and macrophages and SAMHD1 antibodies were prevalent in tertiary lymphoid tissue. An unbiased screen using metagenomic sequencing related SAMHD1 to increased expression of human endogenous retrovirus K (HERV-K) in PAH vs. control lungs (n=4 each). HERV-K envelope and deoxyuridine triphosphate nucleotidohydrolase (dUTPase) mRNAs were elevated in PAH vs. control lungs (n=10) and proteins were localized to macrophages. HERV-K dUTPase induced SAMHD1 and pro-inflammatory cytokines (e.g., IL6, IL1β and TNFα) in circulating monocytes and pulmonary arterial (PA) EC, and activated B cells. Vulnerability of PAEC to apoptosis was increased by HERV-K dUTPase in an IL6 independent manner. Furthermore, three weekly injections of HERV-K dUTPase induced hemodynamic and vascular changes of pulmonary hypertension in rats (n=8), and elevated IL6. Conclusions -Our study reveals that upregulation of the endogenous retrovirus HERV-K could both initiate and sustain activation of the immune system and cause vascular changes associated with PAH.

    View details for PubMedID 28935667

  • Hypoxia Inducible Factor-1 alpha Increases Bone Morphogenetic Protein Receptor 2 Signaling In Pulmonary Artery Endothelial Cells (paecs) Kuang, J., Tian, X., Prosseda, S., Tian, A., Cornfield, D., Nicolls, M. R., Spiekerkoetter, E. F. AMER THORACIC SOC. 2017
  • Dynamics of the human antibody repertoire after B cell depletion in systemic sclerosis Dynamics of the human antibody repertoire after B cell depletion in systemic sclerosis de Bourcy, C. F., Dekker, C. L., Davis, M. M., Nicolls, M. R., Quake, S. R. 2017; 2 (15)
  • Leukotriene B4 Potentiates Bmpr2 Deficiency And Causes Paec Endmt In Pah Tian, A., Jiang, X., Shuffle, E., Tu, A., Jin, Q., Zamanian, R. T., Voelkel, N., Peters-Golden, M., Tuder, R., Rabinovitch, M., Nicolls, M. AMER THORACIC SOC. 2017
  • Delivery Of Il-10 Using A Novel High Molecular Weight Hyaluronan Vehicle Reduces Lung Fibrosis In A Bleomycin Mouse Model Of Lung Injury Shamskhou, E., Orcholski, M., Kaber, G., Yuan, K., Danielson, B., Chapman, H., Nicolls, M., Bollyky, P., Perez, V. AMER THORACIC SOC. 2017
  • Clinical Heterogeneity Across Proteomic Immunophenotypes In Pulmonary Arterial Hypertension Sweatt, A., Hedlin, H., Balasubramanian, V., Hsi, A., Blum, L., Robinson, W., Nicolls, M., Rabinovitch, M., Khatri, P., Zamanian, R. T. AMER THORACIC SOC. 2017
  • Discovery Of Proteomic Immune Signatures In Pulmonary Arterial Hypertension By Unsupervised Consensus Clustering Sweatt, A., Hedlin, H., Balasubramanian, V., Hsi, A., Blum, L., Robinson, W., Nicolls, M. R., Rabinovitch, M., Khatri, P., Zamanian, R. T. AMER THORACIC SOC. 2017
  • Lymphatic Dysfunction, Leukotrienes, and Lymphedema. Annual review of physiology Jiang, X. n., Nicolls, M. R., Tian, W. n., Rockson, S. G. 2017

    Abstract

    The lymphatic system is essential for the maintenance of tissue fluid homeostasis, gastrointestinal lipid absorption, and immune trafficking. Whereas lymphatic regeneration occurs physiologically in wound healing and tissue repair, pathological lymphangiogenesis has been implicated in a number of chronic diseases such as lymphedema, atherosclerosis, and cancer. Insight into the regulatory mechanisms of lymphangiogenesis and the manner in which uncontrolled inflammation promotes lymphatic dysfunction is urgently needed to guide the development of novel therapeutics: These would be designed to reverse lymphatic dysfunction, either primary or acquired. Recent investigation has demonstrated the mechanistic role of leukotriene B4 (LTB4) in the molecular pathogenesis of lymphedema. LTB4, a product of the innate immune response, is a constituent of the eicosanoid inflammatory mediator family of molecules that promote both physiological and pathological inflammation. Here we provide an overview of lymphatic development, the pathophysiology of lymphedema, and the role of leukotrienes in lymphedema pathogenesis. Expected final online publication date for the Annual Review of Physiology Volume 80 is February 10, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

    View details for PubMedID 29029593

  • Introduction to the 59th Annual Thomas L. Petty Aspen Lung Conference. Lung Transplantation: Opportunities for Repair and Regeneration. Annals of the American Thoracic Society Zamora, M. R., Martinu, T. n., Nicolls, M. R. 2017; 14 (Supplement_3): S209

    View details for PubMedID 28945478

  • Aspergillus-related pulmonary diseases in lung transplantation MEDICAL MYCOLOGY Pasupneti, S., Manouvakhova, O., Nicolls, M. R., Hsu, J. L. 2017; 55 (1): 96-102

    Abstract

    While lung transplantation is an attractive treatment option for many end stage lung diseases, the relatively high 5-year mortality continues to be a significant limiting factor. Among the foremost reasons for this is the eventual development of obstructive chronic lung allograft dysfunction. Infections, which the lung allograft is especially prone to, are a major risk factor. Specifically, the Aspergillus species cause a higher burden of disease among lung transplant recipients, due to unique risk factors, such as relative hypoxemia. However, these risk factors also provide unique opportunities for treatment and preventative strategies, as outlined in this review.

    View details for DOI 10.1093/mmy/myw121

    View details for Web of Science ID 000393896500013

  • Models of Lung Transplant Research: a consensus statement from the National Heart, Lung, and Blood Institute workshop. JCI insight Lama, V. N., Belperio, J. A., Christie, J. D., El-Chemaly, S. n., Fishbein, M. C., Gelman, A. E., Hancock, W. W., Keshavjee, S. n., Kreisel, D. n., Laubach, V. E., Looney, M. R., McDyer, J. F., Mohanakumar, T. n., Shilling, R. A., Panoskaltsis-Mortari, A. n., Wilkes, D. S., Eu, J. P., Nicolls, M. R. 2017; 2 (9)

    Abstract

    Lung transplantation, a cure for a number of end-stage lung diseases, continues to have the worst long-term outcomes when compared with other solid organ transplants. Preclinical modeling of the most common and serious lung transplantation complications are essential to better understand and mitigate the pathophysiological processes that lead to these complications. Various animal and in vitro models of lung transplant complications now exist and each of these models has unique strengths. However, significant issues, such as the required technical expertise as well as the robustness and clinical usefulness of these models, remain to be overcome or clarified. The National Heart, Lung, and Blood Institute (NHLBI) convened a workshop in March 2016 to review the state of preclinical science addressing the three most important complications of lung transplantation: primary graft dysfunction (PGD), acute rejection (AR), and chronic lung allograft dysfunction (CLAD). In addition, the participants of the workshop were tasked to make consensus recommendations on the best use of these complimentary models to close our knowledge gaps in PGD, AR, and CLAD. Their reviews and recommendations are summarized in this report. Furthermore, the participants outlined opportunities to collaborate and directions to accelerate research using these preclinical models.

    View details for PubMedID 28469087

  • Simultaneously Targeting Myofibroblast Contractility and Extracellular Matrix Cross-Linking as a Therapeutic Concept in Airway Fibrosis. American journal of transplantation Lin, Y., Sung, Y. K., Jiang, X., Peters-Golden, M., Nicolls, M. R. 2016

    Abstract

    Fibrosis after solid organ transplantation is considered an irreversible process and remains the major cause of graft dysfunction and death with limited therapies. This remodeling is characterized by aberrant accumulation of contractile myofibroblasts that deposit excessive extracellular matrix (ECM) and increase tissue stiffness. However, studies demonstrate that a stiff ECM, itself, promotes fibroblast-to-myofibroblast differentiation, stimulating further ECM production. This creates a positive feedback loop that perpetuates fibrosis. We hypothesized that simultaneously targeting myofibroblast contractility with relaxin and ECM stiffness with lysyl oxidase inhibitors could break the feedback loop, thereby, reversing established fibrosis. To test this, we used the orthotopic tracheal transplanted (OTT) mouse model, which develops robust fibrotic airway remodeling. Mice with established fibrosis were treated with saline, mono-, or combination therapies. While monotherapies had no effect, combining these agents decreased collagen deposition and promoted re-epithelialization of remodeled airways. Relaxin inhibited myofibroblast differentiation and contraction, in a matrix-stiffness-dependent manner through prostaglandin E2 (PGE2 ). Furthermore, the effect of combination therapy was lost in PGE2 receptor knockout and PGE2 inhibited OTT mice. This study reveals the important synergistic roles of cellular contractility and tissue stiffness in the maintenance of fibrotic tissue and suggests a new therapeutic principle for fibrosis. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1111/ajt.14103

    View details for PubMedID 27804215

  • Enhanced Electrochemical Sensing with Carbon Nanotubes Modified with Bismuth and Magnetic Nanoparticles in a Lab-on-a-Chip. ChemNanoMat : chemistry of nanomaterials for energy, biology and more Jothimuthu, P., Hsu, J. L., Chen, R., Inayathullah, M., Pothineni, V. R., Jan, A., Gurtner, G. C., Rajadas, J., Nicolls, M. R. 2016; 2 (9): 904-910

    Abstract

    Iron plays an especially important role in human physiological functions and pathological impairments. The superior properties of carbon nanotubes (CNTs) and their modification with bismuth and magnetic nanoparticles as developed in this work have led to an extraordinary and novel material to facilitate ultrasensitive detection in the nanomolar range. Here, we present the development of an electrochemical sensor for detection of ferrous (Fe(2+)) and ferric (Fe(3+)) iron by means of CNTs modified with bismuth and magnetic nanoparticles for higher sensitivity of detection. The sensor fabrication includes microfabrication methodologies, soft lithography, and electrodeposition. Cyclic voltammetry and differential pulse voltammetry are used for the electroanalytical studies and detection of the ions in samples. The sensor has a dynamic range of detection from 0.01 nm to 10 mm. The performance of the sensor with modified CNTs was explored for sensitivity and specificity. CNTs, modified with bismuth and magnetic nanoparticles by means of electrodeposition, enhanced the detection limit significantly down to 0.01 nm.

    View details for DOI 10.1002/cnma.201600174

    View details for PubMedID 27857882

    View details for PubMedCentralID PMC5110256

  • Enhanced Electrochemical Sensing with Carbon Nanotubes Modified with Bismuth and Magnetic Nanoparticles in a Lab-on-a-Chip CHEMNANOMAT Jothimuthu, P., Hsu, J. L., Chen, R., Inayathullah, M., Pothineni, V. R., Jan, A., Gurtner, G. C., Rajadas, J., Nicolls, M. R. 2016; 2 (9): 904-910

    Abstract

    Iron plays an especially important role in human physiological functions and pathological impairments. The superior properties of carbon nanotubes (CNTs) and their modification with bismuth and magnetic nanoparticles as developed in this work have led to an extraordinary and novel material to facilitate ultrasensitive detection in the nanomolar range. Here, we present the development of an electrochemical sensor for detection of ferrous (Fe(2+)) and ferric (Fe(3+)) iron by means of CNTs modified with bismuth and magnetic nanoparticles for higher sensitivity of detection. The sensor fabrication includes microfabrication methodologies, soft lithography, and electrodeposition. Cyclic voltammetry and differential pulse voltammetry are used for the electroanalytical studies and detection of the ions in samples. The sensor has a dynamic range of detection from 0.01 nm to 10 mm. The performance of the sensor with modified CNTs was explored for sensitivity and specificity. CNTs, modified with bismuth and magnetic nanoparticles by means of electrodeposition, enhanced the detection limit significantly down to 0.01 nm.

    View details for DOI 10.1002/cnma.201600174

    View details for Web of Science ID 000383766800009

    View details for PubMedCentralID PMC5110256