CircINSR Promotes Proliferation and Reduces Apoptosis of Embryonic Myoblasts by Sponging miR-34a

Xuemei Shen,Xiaoyan Zhang,Wenxiu Ru,Yongzhen Huang,Xianyong Lan,Chuzhao Lei,Hong Chen

doi:10.1016/j.omtn.2019.12.032

Xuemei Shen, Xiaoyan Zhang + Show 5 more

Open Access

https://doi.org/10.1016/j.omtn.2019.12.032

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Abstract

As a diverse and abundant class of endogenous RNAs, circular RNAs (circRNAs) participate in processes including cell proliferation and apoptosis. Nevertheless, few researchers have investigated the function of circRNAs in bovine muscle development. Based on existing sequencing data, we identified circINSR. The localization of circINSR in bovine myoblasts was investigated by fluorescence in situ hybridization. Molecular and biochemical assays were used to confirm the role of circINSR in myoblast proliferation and the cell cycle. Mitochondrial membrane potential and annexin V-PE/7-AAD staining assays were performed to assess cell apoptosis. Additionally, interactions between circINSR, miR-34a, and target mRNAs were examined using bioinformatics, a luciferase assay, and RNA immunoprecipitation. We found that circINSR was highly expressed in embryonic muscle tissue. Overexpression of circINSR significantly promoted proliferation and reduced apoptosis of embryonic myoblasts. Our data suggested that circINSR may act as a sponge of miR-34a and could function through de-repression of target genes in muscle cells. This study proposes that circINSR may function as a regulator of embryonic muscle development. circINSR regulates cells proliferation and apoptosis through miR-34a-modulated Bcl-2 and CyclinE2 expression.

Highlights

IntroductionAs the largest motor organ of mammals, is currently the focus of research
Skeletal muscle, as the largest motor organ of mammals, is currently the focus of research
According to the online database CircBase, we found that circINSR is highly homologous to human has_circ_0048966, both of which consist of head-to-tail splicing of insulin receptor (INSR) exon 2 (552 bp). circINSR was only amplified in cDNA by divergent primers, and no amplification product was observed in genomic DNA

Summary

Introduction

As the largest motor organ of mammals, is currently the focus of research. Muscle development is a complex process involving multiple genes and non-coding RNAs (ncRNAs), but the specific mechanisms remain to be explored.[2]. MicroRNAs (miRNAs) are a class of endogenous ncRNAs that inhibit the expression of downstream target genes through post-transcriptional regulation.[3] There is increasing evidence that demonstrates miRNAs regulate a variety of biological processes, including muscle cell proliferation, differentiation, and apoptosis. The elevation of serum levels of miRNAs (miR-1, miR-133, miR-206, miR-208a, miR-208b, and miR-499) was observed in DMD patients.[4,5] miR-1, miR-206, and miR-486 promote muscle cell differentiation by inhibiting the transcription of Pax[7,6,7] while miR-378a-3p promotes skeletal muscle cell differentiation by targeting HDAC4.8 miR-27a targets myostatin and Pax[3] to promote myocyte production and proper migration of myogenic progenitor cells.[9,10] miR-34 has been shown to be a direct transcriptional target of p53, which in turn downregulates the genes required for cell proliferation.[11]

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