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 ... -  《-》

MiR-18a-5p contributes to enhanced proliferation and migration of PASMCs via targeting Notch2 in pulmonary arterial hypertension.

This study is undertaken to investigate the role and molecular mechanisms of miR-18a-5p in regulating pulmonary arterial hypertension (PAH) pathogenesis. Gene expression and protein levels were determined by qRT-PCR and western blot, respectively; Cell counting kti-8 and Transwell migration assays were used to determine the biological functions of miR-18a-5p in pulmonary arterial smooth muscle cells (PASMCs); bioinformatics analysis, luciferase reporter assays were used to elucidate the mechanisms of miR-18a-5p. MiR-18a-5p was up-regulated in the clinical samples from PAH patients. PASMCs treated with hypoxia exhibited enhanced proliferative ability and upregulated miR-18a-5p expression. Knockdown of miR-18a-5p attenuated hypoxia-induced hyper-proliferation and enhanced migratory potential of PASMCs; while miR-18a-5p overexpression promoted PASMC proliferation and migration. Further mechanistic studies showed that Notch2 was a direct target of miR-18a-5p and was repressed by miR-18a-5p overexpression. The rescue studies indicated that Notch2 overexpression counteracted the enhanced proliferation and migration induced by miR-18a-5p mimics in PASMCs. Similarly, Notch2 overexpression also block the effects caused by hypoxia in PASMCs. Moreover, Notch2 expression was down-regulated in the PAH patients and was negatively correlated with miR-18a-5p expression. In vivo animal studies further revealed the up-regulation of miR-18a-5p and the down-regulation of Notch2 in the PAH rats. Collectively, this study identified the up-regulated miR-18a-5p in the PAH patients; our data suggest that miR-18a-5p contributes to the enhanced proliferation and migration of PASMCs via repressing Notch2 expression.

Miao R ，Liu W ，Qi C ，Song Y ，Zhang Y ，Fu Y ，Liu W ，Lang Y ，Zhang Y ，Zhang Z ... -  《-》

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

Lei S ，Peng F ，Li ML ，Duan WB ，Peng CQ ，Wu SJ ... -  《-》

Inhibition of miR-361-5p suppressed pulmonary artery smooth muscle cell survival and migration by targeting ABCA1 and inhibiting the JAK2/STAT3 pathway.

MicroRNAs play a crucial role in the progression of pulmonary arterial hypertension (PAH). The aim of this study was to investigate the effect of miR-361-5p on the proliferation, migration and apoptosis of pulmonary artery smooth muscle cells (PASMCs) that under the treatment of hypoxia and explore the underlying mechanisms. The results proved that hypoxia noticeably up-regulated the expression of miR-361-5p in PASMCs in comparison to the normoxia-treated cells, while TNF-α and IL-6 stimulation had no obvious effects on miR-361-5p level. Hypoxia induced miR-361-5p elevation in a HIF-1α-dependent manner. Inhibition of miR-361-5p dramatically inhibited hypoxia-induced cell proliferation and migration. miR-361-5p inhibition also rescued hypoxia exposure caused suppression of PASMCs apoptosis. In addition, the results showed that ABCA1 was a direct target of miR-361-5p and was down-regulated in hypoxia-induced PASMCs. Hypoxia and TNF-α or IL-6 stimulation significantly inhibited ABCA1 expression. In addition, overexpression of ABCA1 enhanced the effect of miR-361-5p on hPASMCs. Furthermore, the inhibition of miR-361-5p significantly down-regulated the expression level of p-JAK2 and p-STAT3. In conclusion, it may suggest that the suppression of miR-361-5p suppressed PASMC survival and migration by targeting ABCA1 and inhibiting the JAK2/STAT3 pathway.

Zhang X ，Shao R ，Gao W ，Sun G ，Liu Y ，Fa X ... -  《-》

MicroRNA-221-3p promotes pulmonary artery smooth muscle cells proliferation by targeting AXIN2 during pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a pathological condition characterized by excessive cell proliferation and migration of pulmonary arterial smooth muscle cells (PASMC). PAH pathogenesis shares similarities with cancers such as excessive cell proliferation and apoptosis resistance. A previous study by our group revealed that decreased expression of a tumor suppressor-AXIN2 (Axis inhibition protein 2) was responsible for enhanced PASMC proliferation and suppressed apoptosis. Nevertheless, the mechanisms that regulate the downregulation of AXIN2 in PAH remain elusive. Data from the present study demonstrated that miR-221-3p acts as an upstream regulator of AXIN2 and functions to induce PASMC proliferation. We first showed that miR-221-3p expression was elevated in lung tissue and PASMC of PAH patients as well as in animal models of PAH. Human PASMC were transfected with a miR-221-3p mimic and miR-221-3p inhibitor, respectively, and their effects on the proliferation and migration was assessed using BrdU incorporation, PCNA staining and wound healing assays. In addition, we investigated the molecular mechanism through which miR-221-3p contributes to cell proliferation in PASMC and identified AXIN2 as a direct target gene of miR-221-3p by dual luciferase reporter gene assays, qRT-qPCR and western blotting. Furthermore, we found that ectopic expression of AXIN2 or pharmacological inhibition of β-catenin by XAV-939 can attenuate the effect of miR-221-3p on cell proliferation in PASMC. Moreover, intravenous injection of miR-221-3p inhibitor attenuated the progression of SU5416-hypoxia-induced PAH in rats. The results of the present study identified a new regulatory axis in which miR-221-3p and AXIN2 regulate the proliferation of PASMC.

Nie X ，Chen Y ，Tan J ，Dai Y ，Mao W ，Qin G ，Ye S ，Sun J ，Yang Z ，Chen J ... -  《-》