MiR-206 Controls the Phenotypic Modulation of Pulmonary Arterial Smooth Muscle Cells Induced by Serum from Rats with Hepatopulmonary Syndrome by Regulating the Target Gene, Annexin A2

Abstract

Background: Hepatopulmonary syndrome (HPS) is a serious complication of advanced liver disease that is characterised by intrapulmonary vascular dilatation (IPVD) and arterial hypoxemia. Pulmonary vascular remodelling (PVR) is an important pathological feature of HPS, but the potential mechanisms underlying PVR remain undefined. Recent findings have established the essential role of changes in Annexin A2 (ANXA2) in controlling the phenotypic modulation of pulmonary artery smooth muscle cells (PASMCs) in PVR associated with HPS. However, the mechanism by which upstream signalling regulates ANXA2 is unclear. Methods: In the present study, computational analysis was used to predict which miRNA might target the 3´-untranslated region (3´-UTR) of the ANXA2 mRNA. Real-time PCR and western blotting were performed to study the level of correlation between ANXA2 and the differentiation marker with the predicted miRNAs in PASMCs stimulated with serum from normal rats or those with HPS. Functional analysis of the miRNA and a luciferase reporter assay were performed to demonstrate that the predicted miRNA suppressed ANXA2 expression by directly targeting the predicted 3´-UTR site of the ANXA2 mRNA. Results: Computational analysis predicted that miR-206 would target the 3´-UTR of ANXA2 mRNA. In HPS rat serum-stimulated PASMCs, the expression of miR-206 displayed an inverse correlation with ANXA2, while a positive correlation was observed with the phenotypic marker smooth muscle α-actin (SM α-actin). The miRNA functional analysis and luciferase reporter assay demonstrated that miR-206 effectively downregulated the expression of ANXA2 by binding to the 3´-UTR of the ANXA2 mRNA. Consistently, miR-206 effectively inhibited the HPS rat serum-induced phenotypic modulation and proliferation, while these effects were reversed in ANXA2-overexpressing PASMCs. Conclusion: This study demonstrates that miR-206 inhibits the HPS rat serum-induced phenotypic modulation and proliferation in PASMCs by down-regulating ANXA2 gene expression.

rs2910164 Polymorphism Confers a Decreased Risk for Pulmonary Hypertension by Compromising the Processing of microRNA-146a

“…Numerous miRNAs and genes have been reported to be associated with the development of PAH [15,16,17,18]. In this study, we performed a case-control association study to identify the relationship between the rs2910164 polymorphism and risk of PAH.…”

Loss of cell polarity regulated by PTEN/Cdc42 enrolled in the process of Hepatopulmonary Syndrome

“…It has been shown that PTEN localizes to the apical plasma membrane during epithelial morphogenesis to mediate the enrichment of PtdIns (4,5)P2 at this domain during cyst development in three dimensional culture. Then, AX2 binds PtdIns (4,5)P2 and thus is recruited to the apical surface, which in turn recruits Cdc42 to the apical plasma membrane, causing the organization of the sub-apical actin cytoskeleton and formation of the apical surface and lumen. 26 Therefore, we checked whether PTEN interacts with AX2 by using Immunoprecipitation assay.…”

“…This suggested that the increased total PTEN was mainly p-PTEN. Interestingly, it has been shown that AX2 binds PtdIns (4,5)P2 and is recruited to the apical surface. 26 Our previous studies had reported that silencing AX2 expression inhibited cell migration and proliferation in the pathogenesis of HPS.…”

“…Pulmonary vascular remodelling (PVR), which impairs arterial oxygenation in the setting of chronic liver diseases, is the key pathophysiological component of HPS . In our previous studies, we established the role of cell proliferation, migration and phenotype differentiation in PVR associated with HPS …”

A Single Nucleotide Polymorphism in 3' Untranslated Region of Epithelial Growth Factor Receptor Confers Risk for Pulmonary Hypertension in Chronic Obstructive Pulmonary Disease

“…To date, it has been estimated that more than one-third of mRNAs of human genes are regulated by human miRNAs [14]. Accumulative evidence demonstrates that miRNAs are critical for regulating the expression of oncogenes or tumor suppressor genes, which will result in tumorigenesis [15,16] as well as other medical disorders [17,18]. Saunders et al proposed that a single nucleotide change in the "seed sequence" of a target site may affect miRNA binding to target sites in the 3′UTR of human genes [19].…”