Cardioprotective effect of circ_SMG6 knockdown against myocardial ischemia/reperfusion injury correlates with miR‐138‐5p‐mediated EGR1/TLR4/TRIF inactivation
C Huang, Y Qu, F Feng, H Zhang, L Shu… - Oxidative medicine …, 2022 - Wiley Online Library
C Huang, Y Qu, F Feng, H Zhang, L Shu, X Zhu, G Huang, J Xu
Oxidative medicine and cellular longevity, 2022•Wiley Online LibraryIncreased neutrophil recruitment represents a hallmark event in myocardial
ischemia/reperfusion (I/R) injury due to the ensuing inflammatory response. Circular RNAs
(circRNAs) are important regulatory molecules involved in cell physiology and pathology.
Herein, we analyzed the role of a novel circRNA circ_SMG6 in the regulation of neutrophil
recruitment following I/R injury, which may associate with the miR‐138‐5p/EGR1/TLR4/TRIF
axis. Myocardial I/R injury was modeled in vivo by ligation of the left anterior descending …
ischemia/reperfusion (I/R) injury due to the ensuing inflammatory response. Circular RNAs
(circRNAs) are important regulatory molecules involved in cell physiology and pathology.
Herein, we analyzed the role of a novel circRNA circ_SMG6 in the regulation of neutrophil
recruitment following I/R injury, which may associate with the miR‐138‐5p/EGR1/TLR4/TRIF
axis. Myocardial I/R injury was modeled in vivo by ligation of the left anterior descending …
Increased neutrophil recruitment represents a hallmark event in myocardial ischemia/reperfusion (I/R) injury due to the ensuing inflammatory response. Circular RNAs (circRNAs) are important regulatory molecules involved in cell physiology and pathology. Herein, we analyzed the role of a novel circRNA circ_SMG6 in the regulation of neutrophil recruitment following I/R injury, which may associate with the miR‐138‐5p/EGR1/TLR4/TRIF axis. Myocardial I/R injury was modeled in vivo by ligation of the left anterior descending (LAD) artery followed by reperfusion in mice and in vitro by exposing a cardiomyocyte cell line (HL‐1) to hypoxia/reoxygenation (H/R). Gain‐ and loss‐of‐function experiments were performed to evaluate the effect of the circ_SMG6/miR‐138‐5p/EGR1/TLR4/TRIF axis on cardiac functions, myocardial infarction, myocardial enzyme levels, cardiomyocyte activities, and neutrophil recruitment. We found that the EGR1 expression was increased in myocardial tissues of I/R mice. Knockdown of EGR1 was found to attenuate I/R‐induced cardiac dysfunction and infarction area, pathological damage, and cardiomyocyte apoptosis. Mechanistic investigations showed that circ_SMG6 competitively bound to miR‐138‐5p and consequently led to upregulation of EGR1, thus facilitating myocardial I/R injury in mice and H/R‐induced cell injury. Additionally, ectopic EGR1 expression augmented neutrophil recruitment and exacerbated the ensuing I/R injury, which was related to the activated TLR4/TRIF signaling pathway. Overall, our findings suggest that circ_SMG6 may deteriorate myocardial I/R injury by promoting neutrophil recruitment via the miR‐138‐5p/EGR1/TLR4/TRIF signaling. This pathway may represent a potential therapeutic target in the management of myocardial I/R injury.
