ABSTRACT
Objective To explore the effects of miRNA-204 targeted LC3B expression on Ang Ⅱ induced cardiomyocytes hypertrophy.Methods The primary neonatal rat cardiomyocytes served as the research objects and divided into the control group,AngⅡ group,combination-treated group 1 (cardiomyocytes were given Ang Ⅱ stimulation,meanwhile infected by negative control lentivirus vector),combination-treated group 2 (cardiomyocytes were given Ang Ⅱ stimulation,meanwhile infected by lentivirus carrying miRNA-204 overexpression vector) according to different treatments.About 48 h to 72 h after intervention treatment,the cardiomyocyte hypertrophy change was detected by confocal microscopy,the expression of miRNA-204 was analyzed by real time PCR,the protein expression of LC3B was measured by Western blot and targeted gene of miRNA-204 was demonstrated by dual-luciferase reporter assay system.Results Compared with the control group,the cardiomyocyte relative surface area in the Ang Ⅱ group was significantly enlarged,the protein expression of LC3B was significantly increased,the expression of miRNA-204 was upregulated,the differences were statistically significant (P＜0.05).Whereas comparing the combination-treated group 1 with combination-treated group 2,the protein expression of LC3B in the latter was down-regulated and the cell area was reduced (P＜0.05).The further luciferase activity report gene experiment results suggested that miRNA-204 was able to bind to LC3B 3'-UTR and decreased the luciferase activities (P＜0.05),but not to bind its mutated fragment for inactivating luciferase activity(P＞0.05).Conclusion miRNA-204 is able to inhibit Ang Ⅱ induced cardiomyocytes hypertrophy,its action is realized by targeting the expression of LC3B.
ABSTRACT
Objective To explore the effects of miR-34a and the alteration of AMPK/mTOR signal pathway on angiotensin (Ang)Ⅱ-stimulated cardiomyocytes hypertrophy. Methods Neonatal rat cardiomyocytes were cultrued in vitro and were divided into 3 groups:negative control for lentivirus carrying miR-34a group (NC), AngⅡplus lentivirus carrying negative control group (AngⅡ+NC) and AngⅡplus lentivirus carrying miR-34a group (AngⅡ+miR-34a). The relative cell area was detected by confocal microscopy. The expression of miR-34a and hypertrophy-related genes (ANP and β-MHC) were analyzed by real time PCR. The AMPK/mTOR signal pathway was measured by Western blot assay. Results Compared to NC group, the relative cell area was increased in AngⅡ+NC group (P<0.05). But compared with AngⅡ+NC group, the relative cell area was decreased in AngII+miR-34a group (P<0.05). Moreover, compared with NC group, the expression of miR-34a was decreased, and the expression of hyperthophy-related genes(ANP and β-MHC) was up-regulated in AngⅡ+NC group. However, the expression of miR-34a was decreased, and the expression of hyperthophy-related genes (ANP and β-MHC) was down-regulated (P<0.05). Finally, compared to NC group, the ratio of phosphop-AMPK/AMPK was significantly induced in AngII + NC group, but the ratio of phosphop-mTOR/mTOR was significantly decreased (P<0.05). However, compared to AngⅡ+NC group, the ratio of phosphop-AMPK/AMPK was significantly decreased in AngII + miR-34a group, but the ratio of phosphop-mTOR/mTOR was significantly increased (P<0.05). Conclusion miR-34a is able to inhibit myocardial hypertrophy of neonatal rat cardiomyocytes, and its mechanism is partly carried out by the alteration of the signal pathway of AMPK/mTOR.
ABSTRACT
Objective To explore the effect and mechanism of renal denervation combined with Losartan on cardiac hypertrophy in spontaneous hypertensive rats. Methods Spontaneous hypertensive rats with cardiac hypertrophy underwent renal denervation combined with following 4 weeks drug treatments. Transthoracic two-dimensional guided M-mode echocardiography was performed. The expression of hypertrophy-related gene was detected. Left ventricularmass index was calculated and histological sectionsstained with hematoxylin and eosin (HE). Results The characteristics of cardiac hypertrophy was observed in left ventricular tissues with HE staining in12 weeks old spontaneous hypertensive rats.The thickness was increased in those ventricular (IVSs, IVSd, LVPWs and LVPWd). After4 weeks after treatment, histological improvements were observed in both RDN and R+L groups compared with sham group. The improvement was more obvious in R+L group. Similar results were observed in histological sections, ventricular thicknesses (IVSs, IVSd, LVPWs and LVPWd), related-hypertrophy genes (ANP and β-MHC) expression, left ventricular mass idex (LVMI) and the protein expression of inflammatory cytokines (TNF-α and IL-6). Conculsion Renal denervation therapy can improve hypertensive-induced cardiac hypertrophy in spontaneous hypertensive rats. The effect was more significant when combined with Losartan. The mechanism might be involved in inhibiting inflammatory cytokines.