Circ_LAS1L Affects Cardiomyocyte Ferroptosis by Regulating SFRP5 Expression
Objective To study the mechanism of circ_LAS1L regulating the expression of SFRP5 and the role of circ_LAS1L/SFRP5 pathway in ferroptosis of rat cardiomyocytes in the progression of myocardial ischemia-reperfusion injury.Methods Rat embryonic myocardial cells H9c2 cardiomyocytes were cultured and transfected or co-transfected with circ_LAS1L overexpression vector(circ_LAS1L-O),circ_LAS1L siRNA,miR-125b mimic,miR-125b siRNA and SFRP5 siRNA,and then subjected to hypoxia/reoxygenation(H/R)treatment.The expression of circ_LAS1L and miR-125b was detected by RT-qPCR,and the expression of SFRP5 and GPX4 was detected by RT-qPCR and Western blot.Electron microscopy was used to observe changes in mitochondrial structure,and the CCK-8 method was used to detect cell viability.LDH release,ROS,Fe2+and MDA contents were detected via the reagent kits.Results circ_LAS1L overexpression promoted the RNA and protein expression of SFRP5,but circ_LAS1L siRNA had the opposite effect(Pall＜0.05).miR-125b mimic inhibited but miR-125b siRNA promoted the RNA and protein expression of SFRP5,and circ_LAS1L overexpression blocked the role of miR-125b mimic in regulating SFRP5 expression(P all＜0.05);Similarly,circ_LAS1L siRNA could also reverse the regulation of miR-125b siRNA on SFRP5 expression(P all＜0.05).The expression of circ_LAS1L and SFRP5 was increased in H/R-treated cardiomyocytes,while the expression of GPX4 was decreased(P all＜0.05);SFRP5 siRNA could counteract the regulatory effect of circ_LAS1L overexpression on GPX4 expression(Pall＜0.05).H/R led to significant mitochondrial shrinkage and reduced mitochondrial cristae,reduced cell viability,enhanced LDH release,and promoted ROS,Fe2+and MDA accumulation,while circ_LAS1L-O significantly attenuated the above changes caused by H/R,but si-SFRP5 antagonized the effect of circ_LAS1L-O.Conclusion circ_LAS1L can promote the expression of SFRP5 and inhibit the expression of GPX4,the key regulatory factor in ferroptosis,thereby participating in the process of myocardial cell ferroptosis miR-125b can inhibit the expression of SFRP5 and significantly weaken the effect of circ-LAS1L on promoting SFRP5 expression.
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