Background: Atherosclerosis involves a slow process of plaque formation on the walls of arteries, and comprises a leading cause of cardiovascular disease. Long non-coding RNAs (lncRNAs) have been implicated in the pathogenesis of atherosclerosis. In this study, we aim to explore the possible involvement of lncRNA 'cyclin-dependent kinase inhibitor 2B antisense noncoding RNA' (CDKN2B-AS1) and CDKN2B in the progression of atherosclerosis. Methods: Initially, we quantified the expression of CDKN2B-AS1 in atherosclerotic plaque tissues and, in THP-1 macrophage-derived, and human primary macrophage (HPM)-derived foam cells. Next, we established a mouse model of atherosclerosis using apolipoprotein E knockout (ApoE À/À ) mice, where lipid uptake, lipid accumulation, and macrophage reverse cholesterol transport (mRCT) were assessed, in order to explore the contributory role of CDKN2B-AS1 to the progression of atherosclerosis. RIP and ChIP assays were used to identify interactions between CDKN2B-AS1, CCCTC-binding factor (CTCF), enhancer of zeste homologue 2 (EZH2), and CDKN2B. Triplex formation was determined by RNA-DNA pull-down and capture assay as well as EMSA experiment. Findings: CDKN2B-AS1 showed high expression levels in atherosclerosis, whereas CDKN2B showed low expression levels. CDKN2B-AS1 accelerated lipid uptake and intracellular lipid accumulation whilst attenuating mRCT in THP-1 macrophage-derived foam cells, HPM-derived foam cells, and in the mouse model. EZH2 and CTCF were found to bind to the CDKN2B promoter region. An RNA-DNA triplex formed by CDKN2B-AS1 and CDKN2B promoter was found to recruit EZH2 and CTCF in the CDKN2B promoter region and consequently inhibit CDKN2B transcription by accelerating histone methylation. Interpretation: The results demonstrated that CDKN2B-AS1 promotes atherosclerotic plaque formation and inhibits mRCT in atherosclerosis by regulating CDKN2B promoter, and thereby could be a potential therapeutic target for atherosclerosis.

Pulmonary arterial hypertension (PAH) is a fatal cardiovascular disease that could eventually result in right ventricular failure. Recently, the roles of microRNAs (miRNAs) in PAH have been highlighted. The present study aims to investigate the effects of miRNA (miR)-340-5p on PAH induced by acute pulmonary embolism (APE) and the underlying mechanisms. miR-340-5p was lowly expressed, whereas interleukin 1β (IL-1β) and IL-6 were highly expressed in plasma of APE-PAH patients as compared to normal human plasma. Subsequently, IL-1β and IL-6 were confirmed to be two target genes of miR-340-5p using a dual-luciferase reporter gene assay. By conducting overexpression and rescue experiments, overexpression of miR-340-5p was evidenced to inhibit proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) and inflammation via reducing IL-1β and IL-6 levels. Meanwhile, miR-340-5p led to the blocked nuclear factor κB (NF-κB) pathway with reduced NF-κB p65, matrix metalloproteinase 2 (MMP2), and MMP9 expression in PASMCs. Finally, the ameliorative effect of miR-340-5p on pathological lesions was further verified in rat models of APE-PAH. Altogether, overexpressed miR-340-5p inhibited the inflammatory response, proliferation, and migration of PASMCs by downregulating IL-1β and IL-6, thereby suppressing the progression of APE-PAH. miR-340-5p therefore holds promise as an anti-inflammatory therapeutic target.

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Normal pregnancy is associated with systemic vasodilation and decreased vascular contraction, partly due to increased release of endothelium-derived vasodilator substances. Endothelin-1 (ET-1) is an endothelium-derived vasoconstrictor acting via endothelin receptor type A (ETAR) and possibly type B (ETBR) in vascular smooth muscle cells (VSMCs), with additional vasodilator effects via endothelial ETBR. However, the role of ET-1 receptor subtypes in the regulation of vascular function during pregnancy is unclear. We investigated whether the decreased vascular contraction during pregnancy reflects changes in the expression/activity of ETAR and ETBR. Contraction was measured in single aortic VSMCs isolated from virgin, mid-pregnant (mid-Preg, day 12) and late-Preg (day 19) Sprague-Dawley rats, and the mRNA expression, protein amount, tissue and cellular distribution of ETAR and ETBR were examined using RT-PCR, Western blots, immunohistochemistry and immunofluorescence. Phenylephrine (Phe, 10−5 M), KCl (51 mM) and ET-1 (10−6 M) caused VSMC contraction that was in late-Preg < mid-Preg and virgin rats. In VSMCs treated with ETBR antagonist BQ788, ET-1 caused significant contraction that was still in late-Preg < mid-Preg and virgin rats. In VSMCs treated with the ETAR antagonist BQ123, ET-1 caused a small contraction; and the ETBR agonists IRL-1620 and sarafotoxin 6c (S6c) caused similar contraction that was in late-Preg < mid-Preg and virgin rats. RT-PCR revealed similar ETAR, but greater ETBR mRNA expression in pregnant vs. virgin rats. Western blots revealed similar ETAR, and greater protein amount of ETBR in endothelium-intact vessels, but reduced ETBR in endothelium-denuded vessels of pregnant vs. virgin rats. Immunohistochemistry revealed prominent ETBR staining in the intima, but reduced ETAR and ETBR in the aortic media of pregnant rats. Immunofluorescence signal for ETAR and ETBR was less in VSMCs of pregnant vs. virgin rats. The pregnancy-associated decrease in ETAR- and ETBR-mediated VSMC contraction appears to involve downregulation of ETAR and ETBR expression/activity in VSM, and may play a role in the adaptive vasodilation during pregnancy.