Circ_0124644 Serves as a ceRNA for miR-590-3p to Promote Hypoxia-Induced Cardiomyocytes Injury via Regulating SOX4.

Juan Tan,Yafang Du,Dianmei Zeng,Jie Wu,Huilin Chen,Peiyong Jiang,Weinan Pan,Kuang Peng

doi:10.3389/fgene.2021.667724

Abstract

Circular RNA (circRNA) is an important factor for regulating the progression of many cardiovascular diseases, including acute myocardial infarction (AMI). However, the role of circ_0124644 in AMI progression remains unclear. Hypoxia was used to induce cardiomyocytes injury. The expression of circ_0124644, microRNA (miR)-590-3p, and SRY-box transcription factor 4 (SOX4) mRNA was measured by qRT-PCR. Cell counting kit 8 (CCK8) assay and flow cytometry were utilized to detect cell viability, cell cycle progression, and apoptosis. The protein levels of apoptosis markers and SOX4 were determined by western blot (WB) analysis, and the levels of oxidative stress markers were assessed using commercial Assay Kits. Dual-luciferase reporter assay, RIP assay, and RNA pull-down assay were employed to confirm the interaction between miR-590-3p and circ_0124644 or SOX4. Circ_0124644 was upregulated in AMI patients and hypoxia-induced cardiomyocytes. Hypoxia could inhibit cardiomyocytes viability, cell cycle process, and promote apoptosis and oxidative stress, while silencing circ_0124644 could alleviate hypoxia-induced cardiomyocytes injury. In terms of mechanism, circ_0124644 could target miR-590-3p. MiR-590-3p overexpression could relieve hypoxia-induced cardiomyocytes injury. Also, the suppressive effect of circ_0124644 knockdown on hypoxia-induced cardiomyocytes injury could be reversed by miR-590-3p inhibitor. Moreover, SOX4 was found to be a target of miR-590-3p, and its overexpression also could reverse the regulation of miR-590-3p on hypoxia-induced cardiomyocytes injury. Circ_0124644 silencing could alleviate hypoxia-induced cardiomyocytes injury by regulating the miR-590-3p/SOX4 axis, suggesting that it might be a target for alleviating AMI.

Highlights

Acute myocardial infarction (AMI) refers to myocardial necrosis caused by acute, persistent ischemia or hypoxia of coronary arteries (Simms-Thomas, 2000; Lu et al, 2015)
Many studies have confirmed that AMI induces cardiomyocyte apoptosis and oxidative stress, which in turn leads to cardiomyocyte injury (Tang et al, 2018; Huang L. et al, 2020)
All data confirmed that circ_0124644 was a stable and highly expressed Circular RNA (circRNA) in AMI patients and hypoxia-induced cardiomyocytes injury models, and it might be mainly involved in post-transcriptional regulation

Summary

Introduction

Acute myocardial infarction (AMI) refers to myocardial necrosis caused by acute, persistent ischemia or hypoxia of coronary arteries (Simms-Thomas, 2000; Lu et al, 2015). Many studies have confirmed that AMI induces cardiomyocyte apoptosis and oxidative stress, which in turn leads to cardiomyocyte injury (Tang et al, 2018; Huang L. et al, 2020). To clarify the molecular mechanism that affects cardiomyocyte injury and explore the molecular targets to alleviate cardiomyocyte injury is of great significance to improve the prognosis of AMI patients. Studies have found that circRNA is closely related to the progression of a variety of cardiovascular diseases, including AMI (Altesha et al, 2019; Gong et al, 2019). Circ_0010729 was found to alleviate hypoxia-induced cardiomyocytes apoptosis and might be an underlying target for AMI treatment (Lei et al, 2020). Circ_101237 silencing was discovered to protect cardiomyocytes from anoxia/reoxygenation-induced injury, which was considered as a biomarker for AMI therapy (Gan et al, 2020)

Methods

Results

Conclusion