Abstract 14263: Pyruvate Dehydrogenase Kinase 4 Leads to Reduced Endothelial-pericyte Interactions in Pulmonary Arterial Hypertension
Introduction: Pulmonary arterial hypertension (PAH) is a life-threatening disorder characterized by impaired angiogenesis, progressive small vessel loss and occlusive vasculopathy. Pericyte recruitment and establishment of endothelial-pericyte interactions is a critical event to ensure structural integrity and proper function of new vessels. Studies by our group and others have shown that establishment of endothelial-pericyte interactions is reduced in PAH and results in impaired but the mechanisms underlying this defect remain poorly understood. In an effort to identify relevant gene candidates associated with aberrant pericyte behavior, we performed a transcriptome analysis of healthy and PAH lung pericytes followed by computational network analysis.
Hypothesis: PAH pericytes have increased genes involved in cell cycle progression, growth and motility.
Methods: Pericytes were extracted from lungs of healthy (N=6) and PAH (N=6) patients followed by lineage validation using FACS and functional assays. RNA extracted from pericytes was converted into cDNA and used in Illumina microarrays. Expression of top candidate genes was validated in histological sections and purified lung using Taqman qPCR, western blot and immunofluorescence.
Results: Pyruvate dehydrogenase kinase isozyme 4 (PDK4), which suppresses mitochondrial glucose oxidation in favor of anaerobic glycolysis, demonstrated the greatest upregulation in PAH pericytes. Compared to healthy cells, PAH pericytes had higher rate of glycolysis but reduced mitochondrial oxygen consumption and reactive oxygen species (ROS) production using Seahorse analysis. Treatment with PDK4 siRNA in PAH pericytes increased the rate of mitochondrial glucose oxidation, endothelial tube formation and motility.
Conclusions: This is the first study demonstrating differences in gene expression profile that correlate with aberrant pericyte behavior during establishment of endothelial pericyte interactions in PAH. PDK4 inhibitor in PAH may reverse vascular remodeling and help protect against microvessel loss. Efforts to assess the relevance of other altered genes in PAH pericytes could lead to insights into PAH pathobiology and the identification of novel therapeutic targets.
Author Disclosures: K. Yuan: None. N. Shao: None. J. Hennigs: None. M. Orcholski: None. A. Richter: None. J. Wu: None. V. de Jesus Perez: None.
- © 2015 by American Heart Association, Inc.