LncRNA-SMILR modulates RhoA/ROCK signaling by targeting miR-141 to regulate vascular remodeling in pulmonary arterial hypertension.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a fatal progressive disease characterized by an increased blood pressure in the pulmonary arteries. RhoA/Rho-kinase (RhoA/ROCK) signaling activation is often associated with PAH. The purpose of this study is to investigate the role and mechanisms of long non-coding RNA (lncRNA) Smooth muscle-induced lncRNA (SMILR) to activate RhoA/ROCK pathway in PAH.
METHODS: SMILR, microRNA-141 (miR-141) and RhoA were identified by qRT-PCR in PAH patients' serum. MTT, wound-healing assay, CCK-8 assay, and flow cytometry were performed to determine cell viability, migration, proliferation, and cell cycle in human pulmonary arterial smooth muscle cells (hPASMCs) and primary PASMCs from PAH patients. We also performed bioinformatical prediction, luciferase reporter assay and RIP to assess the interaction among SMILR, miR-141 and RhoA. RhoA/ROCK pathway and proliferation-related proteins were measured by Western blotting. Finally, we introduced the shSMILR to monocrotaline--induced PAH rat model, and used the hemodynamic measurement, qRT-PCR and immunohistochemistry to examine the therapeutic effects of shSMILR.
RESULTS: SMILR and RhoA expression were up-regulated, while miR-141 expression was down-regulated in PAH patients. SMILR directly interacted with miR-141, and negatively regulated its expression. Knockdown of SMILR suppressed PASMCs proliferation and migration induced by hypoxia. Furthermore, overexpression of miR-141 could inhibit RhoA/ROCK pathway by binding to RhoA, thereby repressing cell proliferation-related signals. Knockdown of SMILR significantly inhibited the Rho/ROCK activation and vascular remodeling in monocrotaline-induced rats.
CONCLUSION: Knockdown of SMILR effectively elevated miR-141 expression, and in turn inhibited RhoA/ROCK pathway to regulate vascular remodeling and reduce blood pressure in PAH.