Doctor of Philosophy, University of Illinois Chicago (2014)
Bachelor of Science, Florida A. & M. University (2007)
RATIONALE: Maintaining endothelial cells (EC) as a monolayer in the vessel wall depends on their metabolic state and gene expression profile, features influenced by contact with neighboring cells such as pericytes and smooth muscle cells (SMC). Failure to regenerate a normal EC monolayer in response to injury can result in occlusive neointima formation in diseases such as atherosclerosis and pulmonary arterial hypertension.OBJECTIVE: We investigated the nature and functional importance of contact-dependent communication between SMC and EC to maintain EC integrity.METHODS AND RESULTS: We found that in SMC and EC contact co-cultures, bone morphogenetic protein receptor 2 (BMPR2) is required by both cell types to produce collagen IV to activate integrin-linked kinase. This enzyme directs phospho c-Jun N-terminal kinase (p-JNK) to the EC membrane, where it stabilizes presenilin1 and releases Notch1 intracellular domain (N1ICD) to promote EC proliferation. This response is necessary for EC regeneration following carotid artery injury. It is deficient in EC-SMC Bmpr2 double heterozygous mice in association with reduced collagen IV production, decreased N1ICD and attenuated EC proliferation, but can be rescued by targeting N1ICD to EC. Deletion of EC- Notch1 in transgenic mice worsens hypoxia-induced pulmonary hypertension, in association with impaired EC regenerative function associated with loss of pre-capillary arteries. We further determined that N1ICD maintains EC proliferative capacity by increasing mitochondrial mass and by inducing the phosphofructokinase PFKFB3. ChIP-seq analyses showed that PFKFB3 is required for citrate-dependent histone acetylation (H3K27) at enhancer sites of genes regulated by the acetyl transferase p300, and by N1ICD or the N1ICD target MYC and necessary for EC proliferation and homeostasis.CONCLUSIONS: Thus, SMC-EC contact is required for activation of Notch1 by BMPR2, to coordinate metabolism with chromatin remodeling of genes that enable EC regeneration, to maintain monolayer integrity and vascular homeostasis in response to injury.
View details for PubMedID 30582451
Idiopathic or heritable pulmonary arterial hypertension is characterized by loss and obliteration of lung vasculature. Endothelial cell dysfunction is pivotal to the pathophysiology but different causal mechanisms may reflect a need for patient-tailored therapies.Endothelial cells differentiated from induced pluripotent stem cells were compared to pulmonary arterial endothelial cells from the same patients with idiopathic or heritable pulmonary arterial hypertension, to determine whether they shared functional abnormalities and altered gene expression patterns, that differed from those in unused donor cells. We then investigated whether endothelial cells differentiated from pluripotent cells could serve as surrogates to test emerging therapies.Functional changes assessed included adhesion, migration, tube formation, and propensity to apoptosis. Expression of BMPR2 and its target, collagen IV, pSMAD1/5 signaling and transcriptomic profiles were also analyzed.Native pulmonary arterial and induced pluripotent stem cell-derived endothelial cells from idiopathic and heritable pulmonary arterial hypertension patients compared to controls, showed a similar reduction in adhesion, migration, survival, and tube formation, decreased BMPR2 and downstream signaling and collagen IV expression. Transcriptomic profiling revealed high KISS1 related to reduced migration and low CES1, to impaired survival in patient cells. A beneficial angiogenic response to potential therapies, FK-506 and Elafin, was related to reduced SLIT3, an anti-migratory factor.Despite the site of disease in the lung our study indicates that induced pluripotent stem cell derived endothelial cells are useful surrogates to uncover novel features related to disease mechanisms and to better match patients to therapies.
View details for PubMedID 27779452
Blood neutrophils perform an essential host-defense function by directly migrating to bacterial invasion sites to kill bacteria. The mechanisms mediating the transition from the migratory to bactericidal phenotype remain elusive. Here, we demonstrate that TRPM2, a trp superfamily member, senses neutrophil-generated reactive oxygen species and restrains neutrophil migration. The inhibitory function of oxidant sensing by TRPM2 requires the oxidation of Cys549, which then induces TRMP2 binding to formyl peptide receptor 1 (FPR1) and subsequent FPR1 internalization and signaling inhibition. The oxidant sensing-induced termination of neutrophil migration at the site of infection permits a smooth transition to the subsequent microbial killing phase.
View details for DOI 10.1016/j.devcel.2016.07.014
View details for Web of Science ID 000383413000005
View details for PubMedID 27569419