MicroRNA-150 attenuates hypoxia-induced excessive proliferation and migration of pulmonary arterial smooth muscle cells through reducing HIF-1α expression.

Pulmonary arterial hypertension (PAH) is a progressive, fatal disease for which currently there is no curative therapy available. Pathologic changes in this disease involve excessive proliferation and migration of pulmonary artery smooth muscle cells (PASMCs). However, the underlying role of miR-150 in PASMCs remains elusive. Here in this study, miR-150 down-regulation was observed in hypoxia-treated PASMCs. Restoration of miR-150 attenuates hypoxia-treated PASMC proliferation and migration. Luciferase reporter assay showed that miR-150 directly regulated expression of HIF-1α. Moreover, overexpression of HIF-1α impaired the suppressive effect of miR-150 on the proliferative and migratory capacities of PASMCs. Altogether, our findings indicate that miR-150 may exert inhibitory effects on excessive proliferation and migration of PASMCs through down-regulation of HIF-1α, providing new insights into the potential mechanisms of human PAH.

Chen M ，Shen C ，Zhang Y ，Shu H ... -  《-》

miR-143 and miR-145 promote hypoxia-induced proliferation and migration of pulmonary arterial smooth muscle cells through regulating ABCA1 expression.

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. 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. 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. 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.

Yue Y ，Zhang Z ，Zhang L ，Chen S ，Guo Y ，Hong Y ... -  《-》

Hypoxia inducible factor-1 mediates expression of miR-322: potential role in proliferation and migration of pulmonary arterial smooth muscle cells.

Zeng Y ，Liu H ，Kang K ，Wang Z ，Hui G ，Zhang X ，Zhong J ，Peng W ，Ramchandran R ，Raj JU ，Gou D ... -  《Scientific Reports》

HIF-1 alpha-induced up-regulation of miR-9 contributes to phenotypic modulation in pulmonary artery smooth muscle cells during hypoxia.

Pulmonary artery smooth muscle cells (PASMCs) are associated with the development of hypoxic pulmonary hypertension (HPH). Recent studies have implicated a critical role for microRNAs (miRNAs) in HPH; however, their expression and regulation in hypoxia-mediated phenotypic modulation of PASMCs remains largely unclear. Here, we report that miR-9 was induced in hypoxia and involved in a hypoxia-induced phenotypic switch in rat primary PASMCs. Knockdown of miR-9 followed by hypoxia exposure attenuated PASMCs proliferation and enhanced the expression of contractile genes in vascular smooth muscle cells (VSMCs), while overexpression of miR-9 in normoxia promoted a proliferative phenotype in PASMCs. The primary transcripts of miR-9-1 and miR-9-3, but not miR-9-2, increased dramatically after hypoxia, whereas silencing of the hypoxia-associated transcription factor HIF-1α following hypoxia exposure abolished the enhancement of both primary transcripts in PASMCs. Using in silico analysis, we found three putative HIF-1α binding motifs on miR-9-1 and one motif on miR-9-3 located within the 5-kb region upstream of the transcriptional start sites. Chromatin immunoprecipitation assay revealed that hypoxia enhanced the direct interaction between HIF-1α and the regulatory elements of miR-9-1 and miR-9-3. Reporter assays showed that the regulatory regions of miR-9-1 and miR-9-3 behaved as enhancers in a HIF-1α-dependent manner during hypoxia. Taken together, our data uncover a regulatory mechanism involving HIF-1α-mediated up-regulation of miR-9, which plays a role in the hypoxia-induced phenotypic switch of PASMCs.

Shan F ，Li J ，Huang QY 《-》

MicroRNA-103/107 is involved in hypoxia-induced proliferation of pulmonary arterial smooth muscle cells by targeting HIF-1β.

Activation of hypoxia inducible factor-1 (HIF) is a hallmark in hypoxia-induced pulmonary hypertension (HPH). microRNAs play a significant role in regulating proliferation of pulmonary arterial smooth muscle cells (PASMCs) in pulmonary hypertension. Previous studies have shown that HIF-1β is a target of miR-103/107. In this present study, we aimed to investigate whether miR-103/107 regulate vascular remodeling in HPH via HIF-1β. The HPH model was built by hypoxia exposure in rats. Real-time PCR and Western blotting were used to determine the expression of miR-103/107 and HIF-1β. Proliferation of PASMCs was examined by 5-bromo-2'-deoxyuridine (BrdU) incorporation method. The functions of miR-103/107 on PASMCs proliferation, HIF-1α and HIF-1β expression were assessed by transfecting miR-103/107 mimics and inhibitors. Significant down-regulation of miR-103/107 was observed in remodeled intrapulmonary vascular in HPH rats and hypoxia-exposured PASMCs, whereas HIF-1α and HIF-1β expression were up-regulated. Hypoxia exposure induced significant proliferation of PASMCs, overexpression of miR-103/107 inhibited but miR-103/107 inhibitors exacerbated PASMCs proliferation. Gain-of-function and loss-of-function experiments showed that miR-103/107 expression was inversely correlated with HIF-1β level. No significant changes of HIF-1α expression were observed under miR-103/107 mimic treatment. Loss of suppression on HIF-1β by miR-103/107 may contribute to excess proliferation of PASMCs and vascular remodeling in hypoxic pulmonary hypertension.

Deng B ，Du J ，Hu R ，Wang AP ，Wu WH ，Hu CP ，Li YJ ，Li XH ... -  《-》