Role and mechanism of miR-125b in cardiac hypertrophy
10.3867/j.issn.1000-3002.2024.12.001
- VernacularTitle:miR-125b在心肌肥厚中的作用及机制
- Author:
Siyun LI
1
;
Yunqi LIU
1
;
Hua YANG
1
;
Shengjie WANG
1
;
Huishan LUO
1
;
Jianjun GUO
1
;
Qingqing ZHANG
1
;
Lina XUAN
1
Author Information
1. 哈尔滨医科大学药学院,黑龙江 哈尔滨 150081
- Publication Type:Journal Article
- Keywords:
miR-125b;
Nav1.5;
Cav1.2;
cardiac hypertrophy
- From:
Chinese Journal of Pharmacology and Toxicology
2024;38(12):887-896
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVE To investigate the role and mechanism of microRNA-125b (miR-125b) in downregulating ion channel-related protein expression in a cardiac hypertrophy model.METHODS① In vivo:Lentiviral vectors for miR-125b overexpression and knockdown were constructed,and male C57BL/6 mice were divided into the following groups:sham group (thoracotomy without virus injection),LV-miR-125b group (mmu-miR-125b mimic),LV-miR-125b-inhibitor group (mmu-miR-125b-inhibitor),and negative control group (LV-NC).The mice were raised under normal conditions for 4 weeks.The ultrastructural changes in myocardium tissue sections of LV-miR-125b mice were observed using trans-mission electron microscopy.The cardiac hypertrophy model in mice was established using thoracic aortic constriction (TAC).Echocardiography was performed to measure ejection fraction (EF) and frac-tional shortening (FS),and the ratio of heart weight to body weight (HW/BW),ratio of heart weight to tibia length (HW/TL),as well as the expression level of the myocardial hypertrophy marker β-myosin heavy chain (β-MHC) were calculated to evaluate the success of the TAC-induced hypertrophy model.Subse-quently,C57BL/6 mice were divided into four groups:Sham group,TAC model group,LV-miR-125b-inhibitor+TAC group,and LV-NC+TAC group.Protein expression levels of cardiac sodium channel (Nav1.5) and calcium channel (Cav1.2) were detected using Western blotting.RT-qPCR was performed to assess the levels of miR-125b and mRNA expression of myocardial hypertrophy markers,including atrial natriuretic peptide (ANP),brain natriuretic peptide (BNP),and β-MHC.② In vitro:Primary cultured neonatal Kunming mouse cardiomyocytes were divided into four groups:cell control group (no treatment),miR-125b overexpression group,miR-125b-inhibitor group,and negative control group (NC).RT-qPCR was used to detect the levels of miR-125b,ANP,BNP,and β-MHC.Western blotting and immunofluorescence were performed to assess the expression levels of Nav1.5 and Cav1.2 in the cardiomyocytes.Luciferase reporter gene assay was used to evaluate the direct effect of miR-125b on the target proteins Nav1.5 and Cav1.2.RESULTS ① In vivo:Compared to the Sham group,the TAC model mice showed significantly increased the ratio of heart weight to body weight (HW/BW),the ratio of heart weight to tibia length (HW/TL),and expression levels of the myocardial hypertrophy marker β-MHC (P＜0.05),indicating the successful establishment of the TAC model.Furthermore,miR-125b expression was significantly elevated in the TAC model group (P＜0.01).In the LV-miR-125b group,compared to the LV-NC group,the expression levels of myocardial hypertrophy markers ANP,BNP,and β-MHC were significantly increased (P＜0.01),while the ejection fraction (EF) and fractional short-ening (FS) values of the mice were significantly reduced (P＜0.01).Additionally,Additionally,myocardium ultrastructure of LV-miR-125b group was damaged.Compared to the LV-NC+TAC group,the LV-miR-125b-inhibitor+TAC group showed a significant increase in ejection fraction (EF) and fractional shortening (FS) values (P＜0.05).Additionally,the levels of Nav1.5 and Cav1.2 in myocardium tissue were signifi-cantly elevated in the LV-miR-125b-inhibitor+TAC group compared to the LV-NC+TAC group (P＜0.05).② In vitro:Compared to the NC group,the miR-125b overexpression group showed a significant increase in miR-125b expression (P＜0.01),as well as elevated levels of ANP,BNP,and β-MHC (P＜0.01).However,miR-125b-inhibitor significantly reversed the increases in ANP,BNP,and β-MHC (P＜0.01).Western blotting and immunofluorescence results showed that,compared to the NC group,the miR-125b mimic group exhibited significantly decreased levels of Nav1.5 and Cav1.2 (P＜0.01),while miR-125b-inhibitor led to an increase in the levels of both Nav1.5 and Cav1.2.Luciferase assay results demon-strated that miR-125b directly binds to the ion channel proteins Nav1.5 and Cav1.2,encoded by the SCN5A and CACNA1C genes.CONCLUSION miR-125b promotes the development of cardiac hyper-trophy by inhibiting the voltage-gated ion channel proteins Nav1.5 and Cav1.2 Inhibition of miR-125b expression improves cardiac hypertrophy.
