lncRNA VELRP Modulates Pulmonary Arterial Smooth Muscle Cell Proliferation and Promotes Vascular Remodeling in Pulmonary Hypertension.

Background: Pulmonary hypertension is a devastating vascular disorder characterized by extensive pulmonary vascular remodeling, ultimately leading to right ventricular failure and death. Activation of PDGF (platelet-derived growth factor) signaling promotes the hyperproliferation of pulmonary arterial smooth muscle cells (PASMCs), thus contributing to the pulmonary vascular remodeling. However, the molecular mechanisms that govern hyperproliferation of PASMCs induced by PDGF remain largely unknown, including the contribution of long noncoding RNAs (lncRNAs). In this study, we aimed to identify a novel lncRNA regulated by PDGF implicated in PASMC proliferation in pulmonary vascular remodeling.

Methods: RNA-sequencing analysis was conducted to identify a novel lncRNA named vessel-enriched lncRNA regulated by PDGF-BB (platelet-derived growth factor-BB; VELRP). Functional investigations of VELRP were performed using knockdown and overexpression strategies along with RNA sequencing. Validation of the function and potential mechanisms of VELRP was performed through Western blot, RNA immunoprecipitation, and chromatin immunoprecipitation assays.

Results: We identified a novel vessel-enriched lncRNA with an increased response to PDGF-BB stimulus. VELRP was identified as an evolutionarily conserved RNA molecule. Modulation of VELRP in PASMCs significantly altered cell proliferation. Mechanistically, VELRP enhances trimethylation of H3K4 (histone H3 lysine 4) by interacting with WDR5 (WD repeat-containing protein 5), leading to increased expression of CDK (cyclin-dependent kinase) 1, CDK2, and CDK4 and consequent hyperproliferation of PASMCs. The pathological relevance of VELRP upregulation in pulmonary artery was confirmed using rat pulmonary hypertension models in vivo, as well as in PASMCs from patients with idiopathic pulmonary arterial hypertension. Specific knockdown of VELRP in smooth muscle cells using adeno-associated virus type 9 SM22α (smooth muscle protein 22α) promoter-shRNA-mediated silencing of VELRP resulted in a significant decrease in right ventricular systolic pressure and vascular remodeling in rat pulmonary hypertension model.

Conclusions: VELRP, as an lncRNA upregulated by PDGF-BB, mediates PASMC proliferation via WDR5/CDK signaling. In vivo studies demonstrate that targeted intervention of VELRP in smooth muscle cells can prevent the development of pulmonary hypertension.