Background: Excessive proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) play an important role in the occurrence and development of pulmonary arterial hypertension (PAH). miR-143/145 was reported to be up-regulated in the animal models and PAH patients, and deletion of miR-143/145 cluster prevented the development of hypoxia-induced pulmonary hypertension, but its underlying mechanism has not been elucidated.

Methods: qRT-PCR and Western blot were performed to detect the expressions of miR-143/145 and ATP-binding cassette transporter A1 (ABCA1) in PAH patients and PASMCs under hypoxic conditions. Cell proliferation and migration were assessed by Cell Counting Kit-8 and wound-healing assay, respectively. Luciferase reporter assay and RNA immunoprecipitation were conducted to confirm the interaction between miR-143/145 and ABCA1. Hypoxia-induced PAH rat model was established to confirm the functions of miR-143/145 in the pathogenesis of PAH and its underlying mechanism in vivo.

Results: miR-143 and miR-145 were up-regulated and ABCA1 was down-regulated in PAH patients and PASMCs under hypoxic conditions for different time, as well as hypoxia-induced PAH rats. miR-143/145 inhibition and ABCA1 overexpression suppressed hypoxia-induced proliferation and migration in PASMCs. ABCA1 was identified as a direct target of miR-143/145 in PASMCs. Moreover, ABCA1 partially reversed miR-143/145-mediated promotion of hypoxia-induced cell proliferation and migration in PASMCs. Furthermore, in vivo experiments confirmed that inhibition of miR-143/145 prevents hypoxia-induced pulmonary hypertension and pulmonary vascular remodeling by targeting ABCA1.

Conclusion: miR-143/145 promoted hypoxia-induced proliferation and migration of PASMCs by targeting ABCA1, contributing to better understanding of the mechanism underlying the pathogenesis of PAH.