Endogenous reduction of miR-185 accelerates cardiac function recovery in mice following myocardial infarction via targeting of cathepsin K.

Chuan‐Chang Li,Quan Sun,Xue‐Ting Qiu,Hui‐Jun Yang,Can‐E Tang,Ling‐Fang He,Wan‐Zhou Wu,Ji‐Peng Zhou,Guo‐Gang Zhang,Yong‐Ping Bai

doi:10.1111/jcmm.14016

Abstract

Angiogenesis is critical for re‐establishing the blood supply to the surviving myocardium after myocardial infarction (MI) in patients with acute coronary syndrome (ACS). MicroRNAs are recognised as important epigenetic regulators of endothelial function. The aim of this study was to determine the roles of microRNAs in angiogenesis. Eighteen circulating microRNAs including miR‐185‐5p were differently expressed in plasma from patients with ACS by high‐throughput RNA sequencing. The expressional levels of miR‐185‐5p were dramatically reduced in hearts isolated from mice following MI and cultured human umbilical vein endothelial cells (HUVECs) under hypoxia, as determined by fluorescence in situ hybridisation and quantitative RT‐PCR. Evidence from computational prediction and luciferase reporter gene activity indicated that cathepsin K (CatK) mRNA is a target of miR‐185‐5p. In HUVECs, miR‐185‐5p mimics inhibited cell proliferations, migrations and tube formations under hypoxia, while miR‐185‐5p inhibitors performed the opposites. Further, the inhibitory effects of miR‐185‐5p up‐regulation on cellular functions of HUVECs were abolished by CatK gene overexpression, and adenovirus‐mediated CatK gene silencing ablated these enhancive effects in HUVECs under hypoxia. In vivo studies indicated that gain‐function of miR‐185‐5p by agomir infusion down‐regulated CatK gene expression, impaired angiogenesis and delayed the recovery of cardiac functions in mice following MI. These actions of miR‐185‐5p agonists were mirrored by in vivo knockdown of CatK in mice with MI. Endogenous reductions of miR‐185‐5p in endothelial cells induced by hypoxia increase CatK gene expression to promote angiogenesis and to accelerate the recovery of cardiac function in mice following MI.

Highlights

Acute coronary syndrome (ACS) remains a major cause of morbidity and mortality worldwide, in which ischaemic complication represents the leading cause in cardiovascular diseases, such as hypertension and atherosclerosis.[1]
We have found that 18 circulating microRNAs including miR‐185‐5p were differently expressed in patients with ACS
We demonstrated that endogenous reduction of miR‐185‐5p expression in endothelial cells during hypoxia up‐regulated cathepsin K (CatK) gene expression and activated multiple cellular functions such as proliferation, migration and tube formation

Summary

| INTRODUCTION

Acute coronary syndrome (ACS) remains a major cause of morbidity and mortality worldwide, in which ischaemic complication represents the leading cause in cardiovascular diseases, such as hypertension and atherosclerosis.[1]. Based on the aforementioned studies, we tested the hypothesis that hypoxia affects endogenous microRNA expressions to promote angiogenesis in ischaemic heart. We firstly got 18 differentially expressed circulating microRNAs in plasma from ACS patients by using high‐throughput sequencing and identified the function of miR‐185‐5p as a key regulator of angiogenesis by targeting cathepsin K (CatK), which plays an important role in regulating vascular repair.[14] In vivo studies demonstrated that endogenous reduction of miR‐185‐5p was vital to the recovery of heart function after ischaemia in mice with MI. The DNA fragments in the libraries were denatured with 0.1 mol/L NaOH to generate single−stranded DNA molecules They were observed on Illumina flow cells, amplified in situ and sequenced for 36 cycles with an Illumina HiSeq 2000 (Illumina), according to the manufacturer's instructions. Statistical analysis was conducted using IBM SPSS statistics 20.0 (IBM Corp., Armonk, NY, USA) and P < 0.05 were considered as statistical significance

| MATERIALS AND METHODS

| RESULTS

| DISCUSSION

DISCLOSURE