Identification of key driver genes in idiopathic pulmonary arterial hypertension by single-cell RNA sequencing and experimental validation.

Idiopathic pulmonary arterial hypertension (IPAH) is characterized by irreversible pulmonary vascular remodeling. This pathological remodeling is mainly driven by the aberrant proliferation and migration of pulmonary artery smooth muscle cells (PASMCs). However, the molecular mechanisms underlying these dysfunctions remain incompletely understood. In this study, we integrated single-cell RNA sequencing (scRNA-seq) analysis with in vivo and in vitro validation to identify key driver genes implicated in IPAH. The GSE169471 dataset was acquired from the Gene Expression Omnibus and processed via quality control, clustering, and cell subtype annotation. Further analyses identified dominant cell subtypes, cell-cell communication networks, and differentially expressed genes (DEGs). Hub genes were then screened using multiple bioinformatic algorithms. The selected hub genes were validated in pulmonary arteries from a monocrotaline (MCT)-induced PAH rat model via qPCR and Western blotting. Furthermore, siRNA-mediated knockdown was conducted to investigate the effects of hub gene silencing on HMGB1-induced PASMC proliferation and migration. Our results revealed that SMCs were the dominant communicating cell subtype and were significantly increased in IPAH. A total of 63 upregulated DEGs were identified, primarily enriched in biological processes such as extracellular matrix organization and signaling pathways, including the focal adhesion pathway. Four hub genes (COL1A1, MYL9, COL1A2, and TPM2) were identified, with significantly increased expression observed in the pulmonary arteries of PAH rats. Subsequently, silencing these genes notably reduced HMGB1-induced PASMC proliferation and migration. These findings provide novel insights into the molecular mechanisms of IPAH and highlight these hub genes as potential therapeutic targets.