RNA Expression Profiling of Lung Tissue Identifies Mutually Distinct Molecular Signatures in PAH and PH Secondary to IPF

Idiopathic pulmonary arterial hypertension (PAH) is a life-threatening condition characterized by pulmonary arteriolar remodeling, and is frequently associated with right heart failure. This study identifies significant novel biological changes in eight genes and several genetic pathways, that were likely to contribute to the pathogenesis of PAH. We also demonstrate that PAH and PH secondary to idiopathic pulmonary fibrosis (IPF) are characterized by distinct gene expression signatures, implying distinct pathophysiological mechanisms. Keywords: disease versus control Keywords: Expression profiling by array Fresh frozen lung tissue specimens from PAH subjects (n=18), IPF subjects with secondary PH (n=8), and normal controls (n=13) were obtained from the University of Pittsburgh Health Sciences Tissue Bank following approval by the University of Pittsburgh Institutional Review Board. Total RNA was isolated from lung tissue using Trizol (Invitrogen) and purified using the RNeasy Mini kit (Qiagen). RNA quantity and quality was assessed using Agilent Nanodrop and Agilent 2100 Bioanalyzer, respectively. 500 ng of total RNA meeting was Cy3 labeled using the Agilent Low RNA Input Linear Amplification Kit PLUS (One-Color). After purification and fragmentation, aliquots of each sample were hybridized to an Agilent Whole Human Genome 4 X 44K microarray, sequentially washed, and scanned on an Agilent DNA microarray scanner.