Abstract 11703: Proteomic Analysis for the Formation of the Plexiform Lesions of a Rat Pulmonary Arterial Hypertension Model

Abstract

Introduction: Although plexiform lesions (PLs) are the hallmark of the severe pulmonary arterial hypertension, the mechanism of this lesion formation has not been fully elucidated. In this study, to explore the pathways associated PLs formation, we examined the proteome analysis using vascular tissue before and after the formation of PLs obtained by laser capture microdissection (LCM). Methods: 7 weeks old rats were injected Sugen 5416 subcutaneously, followed by exposed to hypoxia for 3 weeks. In addition, the rats were kept in room air for 5 weeks (8-week model) or 10 weeks (13-week model) thereafter. We obtained the tissue of vessels with medial hypertrophy from 8-week models (n=5) and PLs from 13-week models (n=5) by LCM. Those micro-dissected samples were then subject to a qualitative and then quantitative proteomics approach. Differentially expressed proteins (DEPs) were defined by abundance in mass spectrometry (MS) (P-value < 0.05 and |log2 (fold change)| > 0.5 or proteins deteced only in lesions extracted from one model). In addition, we investigated enhanced pathway by gene ontology (GO) analysis of the identified DEPs in each of the 8-week and 13-week models. Results: We identified 718 uniquely expressed proteins including 57 DEPs (31 in 8-week model versus 26 in 13-week model) by using LCM-MS. GO analysis revealed that the actin cytoskeleton organization, actin filament-based process, and actomyosin structure organization processes were enhanced in 8-week model. On the other hand, the innate immune system, G2/M check points, and cellular response to reactive oxygen species were enhanced in 13-week model. Conclusion: Pulmonary vascular lesions of 8-week and PLs of 13-week Sugen hypoxia model evaluated by proteomics using samples obtained by LCM methods showed differential protein expression. Analysis of these DEPs may contribute to elucidate the mechanisms of PLs formation.