WHOLE EXOME SEQUENCING REVEALS TOPBP1 AS A NOVEL GENE IN IDIOPATHIC PULMONARY ARTERIAL HYPERTENSION.
American journal of respiratory and critical care medicine
Tie2-dependent VHL knockdown promotes airway microvascular regeneration and attenuates invasive growth of Aspergillus fumigatus
JOURNAL OF MOLECULAR MEDICINE-JMM
2013; 91 (9): 1081-1093
MiR-133a Modulates Osteogenic Differentiation of Vascular Smooth Muscle Cells
2013; 154 (9): 3344-3352
MicroRNAs: promising therapeutic targets for the treatment of pulmonary arterial hypertension
EXPERT OPINION ON THERAPEUTIC TARGETS
2013; 17 (5): 557-564
Rationale: Idiopathic pulmonary arterial hypertension (IPAH) is a life-threatening disorder characterized by progressive loss of pulmonary microvessels. While mutations in the bone morphogenetic receptor (BMPR) 2 are found in 80% of heritable and ±15% of IPAH patients, their low penetrance (±20%) suggests that other as-yet unidentified genetic modifiers are required for manifestation of the disease phenotype. Use of whole exome sequencing (WES) has recently led to the discovery of novel susceptibility genes in heritable PAH but whether WES can also accelerate gene discovery in IPAH remains unknown. Objectives: To determine whether WES can help identify novel gene modifiers in IPAH patients. Methods and Measurements: Exome capture and sequencing was performed on genomic DNA isolated from 12 unrelated IPAH patients lacking BMPR2 mutations. Observed genetic variants were prioritized according to their pathogenic potential using ANNOVAR. Main Results: A total of 10 genes were identified as high priority candidates. Our top hit was TopBP1, a gene involved in the response to DNA damage and replication stress. We found that TopBP1 expression was reduced in vascular lesions and pulmonary endothelial cells isolated from IPAH patients. While TopBP1 deficiency made endothelial cells susceptible to DNA damage and apoptosis in response to hydroxyurea, its restoration resulted in less DNA damage and improved cell survival. Conclusions: WES led to the discovery of TopBP1, a gene whose deficiency may increase susceptibly to small vessel loss in IPAH. We predict that use of WES will help identify gene modifiers that influence an individual's risk of developing IPAH.
View details for DOI 10.1164/rccm.201310-1749OC
View details for PubMedID 24702692
Loss of adenomatous poliposis coli-a3 integrin interaction promotes endothelial apoptosis in mice and humans.
2012; 111 (12): 1551-1564
MicroRNAs (miRNAs) are small noncoding RNAs that not only regulate gene expression during normal development but can also be active players in several diseases. To date, several studies have demonstrated a possible role for specific miRNAs in the regulation of pulmonary vascular homeostasis suggesting that novel therapeutic agents which target these modulators of gene expression could serve to treat pulmonary arterial hypertension (PAH). AREAS COVERED: The characterization of miRNA-mediated gene modulation in the pulmonary circulation is expanding very rapidly. This review summarizes current relevant findings on the role of miRNAs in the pathogenesis of PAH and expands on the potential use of agents that target these molecules as future disease-modifying therapies. EXPERT OPINION: Further understanding of miRNA biology and function in the pulmonary circulation will serve to further enhance our understanding of their contribution to the pathogenesis of PAH. The implementation of a systems biology approach will help accelerate the discovery of miRNAs that influence angiogenesis and cellular responses to vascular injury. Experimental characterization of these miRNAs using in vitro and in vivo methods will be required to validate the biological roles of these miRNAs prior to the consideration of their use as therapeutic targets in future clinical trials.
View details for DOI 10.1517/14728222.2013.765863
View details for Web of Science ID 000317935400008
Loss of Adenomatous Poliposis Coli-alpha 3 Integrin Interaction Promotes Endothelial Apoptosis in Mice and Humans
2012; 111 (12): 1551-?
Role of miR-148a in Hepatitis B Associated Hepatocellular Carcinoma
2012; 7 (4)
Pulmonary hypertension (PH) is characterized by progressive elevation in pulmonary pressure and loss of small pulmonary arteries. As bone morphogenetic proteins promote pulmonary angiogenesis by recruiting the Wnt/?-catenin pathway, we proposed that ?-catenin activation could reduce loss and induce regeneration of small pulmonary arteries (PAs) and attenuate PH.This study aims to establish the role of ?-catenin in protecting the pulmonary endothelium and stimulating compensatory angiogenesis after injury.To assess the impact of ?-catenin activation on chronic hypoxia-induced PH, we used the adenomatous polyposis coli (Apc(Min/+)) mouse, where reduced APC causes constitutive ?-catenin elevation. Surprisingly, hypoxic Apc(Min/+) mice displayed greater PH and small PA loss compared with control C57Bl6J littermates. PA endothelial cells isolated from Apc(Min/+) demonstrated reduced survival and angiogenic responses along with a profound reduction in adhesion to laminin. The mechanism involved failure of APC to interact with the cytoplasmic domain of the ?3 integrin, to stabilize focal adhesions and activate integrin-linked kinase-1 and phospho Akt. We found that PA endothelial cells from lungs of patients with idiopathic PH have reduced APC expression, decreased adhesion to laminin, and impaired vascular tube formation. These defects were corrected in the cultured cells by transfection of APC.We show that APC is integral to PA endothelial cells adhesion and survival and is reduced in PA endothelial cells from PH patient lungs. The data suggest that decreased APC may be a cause of increased risk or severity of PH in genetically susceptible individuals.
View details for DOI 10.1161/CIRCRESAHA.112.267849
View details for PubMedID 23011394
Hepatitis B virus encoded X antigen (HBx) is a trans-regulatory protein that alters the activity of selected transcription factors and cytoplasmic signal transduction pathways. HBx transcriptionally up-regulates the expression of a unique gene, URG11, which in turn transcriptionally up-regulates ?-catenin, thereby contributing importantly to hepatocarcinogenesis. HBx and URG11 also alter the expression of multiple microRNAs, and by miRNA array analysis, both were shown to promote the expression of miR-148a. Elevated miR-148a was also seen in HBx positive liver samples from infected patients. To study the function of miR-148a, anti-148a was introduced into HepG2 and Hep3B cells stably expressing HBx or stably over-expressing URG11. Anti-miR-148a suppressed cell proliferation, cell cycle progression, cell migration, anchorage independent growth in soft agar and subcutaneous tumor formation in SCID mice. Introduction of anti-miR-148a increased PTEN protein and mRNA expression, suggesting that PTEN was targeted by miR-148a. Anti-miR-148a failed to suppress PTEN expression when co-transfected with reporter gene mutants in the 3'UTR of PTEN mRNA. Introduction of anti-miR-148a also resulted in depressed Akt signaling by HBx and URG11, resulting in decreased expression of ?-catenin. Thus, miR-148a may play a central role in HBx/URG11 mediated HCC, and may be an early diagnostic marker and/or therapeutic target associated with this tumor type.
View details for DOI 10.1371/journal.pone.0035331
View details for Web of Science ID 000305014500055
View details for PubMedID 22496917