Aim

This study aimed to investigate the regulatory role of differentially-expressed circular RNAs (circRNAs) in mouse cardiomyocytes during doxorubicin (DOX)-induced cardiotoxicity.

Main methods

Two groups of mice were injected with equal volumes (0.1 mL) of normal saline and DOX. Mouse heart tissue was isolated and digested for total RNA extraction and then subjected to next-generation RNA-sequencing. Expression profiles of circRNAs and circRNA-miRNA-mRNA networks were also constructed. Overall, 48 upregulated and 16 downregulated circRNAs were found to be statistically significant (p < 0.05) in the DOX-injected group. Bioinformatics analysis revealed several potential biological pathways that might be related to apoptosis caused by DOX-induced cardiotoxicity. In addition, using qRT-PCR, we found that a circRNA coded by the Arhgap12 gene, termed circArhgap12, was upregulated in the mouse heart tissue upon DOX intervention. CircArhgap12 enhanced apoptotic cell rate, as assessed using terminal-deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay, and increased reactive oxygen species and malondialdehyde release as well as superoxide dismutase and caspase-3 activation. Using a luciferase reporter assay, we found that circArhgap12 could sponge miR-135a-5p. In rat primary cardiomyocytes, we found that si-circArhgap12 promoted apoptosis and oxidative stress by sponging the miR-135a-5p inhibitor. Using bioinformatics analysis and luciferase reporter assay, we found that miR-135a-5p might have a potential target site for ADCY1 mRNA.

Key findings

Our research demonstrated that the expression profile of circRNAs was modified significantly and that circArhgap12 might play a competitive role among endogenous RNAs in mouse cardiomyocytes during DOX-induced cardiotoxicity.

Significance

Our study may provide a preliminary understanding of DOX-induced cardiotoxicity modulated by circRNA and its competing endogenous RNAs network.

中文翻译：

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环状RNA Arhgap12通过使miR-135a-5p变海绵来调节阿霉素诱导的心脏毒性

目标

这项研究旨在调查阿霉素（DOX）诱导的心脏毒性过程中差异表达的环状RNA（circRNA）在小鼠心肌细胞中的调节作用。

主要方法

两组小鼠分别注射等体积（0.1 mL）的生理盐水和DOX。分离小鼠心脏组织并消化以提取总RNA，然后进行下一代RNA测序。还构建了circRNA和circRNA-miRNA-mRNA网络的表达谱。总体而言，发现48个上调的circRNA和16个下调的circRNA具有统计学意义（p <0.05）在注射DOX的组中。生物信息学分析揭示了几种潜在的生物学途径，这些途径可能与DOX诱导的心脏毒性引起的细胞凋亡有关。此外，使用qRT-PCR，我们发现在DOX干预下，小鼠心脏组织中由Arhgap12基因编码的circRNA（称为circArhgap12）被上调。使用末端脱氧核苷酸转移酶介导的dUTP-生物素缺口末端标记测定法评估，CircArhgap12可提高凋亡细胞率，并增加活性氧和丙二醛释放以及超氧化物歧化酶和caspase-3活化。使用荧光素酶报告基因分析，我们发现circArhgap12可以使miR-135a-5p脱毛。在大鼠原代心肌细胞中，我们发现si-circArhgap12通过海绵miR-135a-5p抑制剂促进细胞凋亡和氧化应激。

主要发现

我们的研究表明，circRNA的表达谱被显着修饰，并且CircArhgap12可能在DOX诱导的心脏毒性期间在小鼠心肌细胞的内源性RNA之间起竞争作用。

意义

我们的研究可能提供由circRNA及其竞争性内源RNA网络调节DOX诱导的心脏毒性的初步了解。