Detection and characterization of long noncoding RNAs in hypoxia-induced pulmonary hypertension

Abstract

Background. Vascular remodelling, a pathogenic hallmark in pulmonary hypertension (PH), is mainly driven by a dysbalance between excessive proliferation and resistance to apoptosis of pulmonary artery smooth muscle cells (PASMC). Aims. We have shown previously that small noncoding RNAs (e.g. microRNAs) are involved in the pathogenesis of PH. However, the role of long noncoding RNAs (lncRNAs) has not been addressed so far. Methods. The expression of lncRNAs was quantified in human PASMC from healthy donors exposed to hypoxia (1% O2) using human RT2 lncRNA PCR arrays (Qiagen) and quantitative PCR. Knockdown of lncRNAs in PASMC was performed by transfection of GapmeRs (Exiqon). Proliferation, migration, and apoptosis were measured using BrdU incorporation wound healing, caspase 3/7 activity assays, respectively. The mouse model of hypoxia-induced PH (5 weeks at 10% O2) was used to determine the levels of lncRNAs in vivo. Results. The expression of 84 selected lncRNAs was assessed in hypoxic PASMC and, among others, the levels of metastasis associated lung adenocarcinoma transcript 1 (MALAT1) were found to be significantly increased. Silencing of MALAT1, significantly decreased proliferation, migration and, in turn, increased apoptosis of PASMC. Using the hypoxia-induced PH mouse model, MALAT1 expression was found to be significantly increased in lungs as compared to control mice. Conclusions. We provide here evidence that MALAT1 expression is significantly increased in hypoxia-induced PH in vitro and in vivo. Knockout experiments confirmed that MALAT1 is involved in the regulation of proliferation and apoptosis indicating a potential role of MALAT1 in pulmonary vascular remodelling.