ABSTRACT
Objective To investigate the role and possible mechanism of microRNA(miR)144-3p in promoting cardiomyocyte hypertrophy. Methods Forty-five C57BL/ 6 mice were divided into control group, myocardial hypertrophy model group (model group), and miR144-3p transfection group (transfection group) according to their transfection method. The cardiac function related indexes of three groups of mice were detected. HE staining was performed on mouse myocardial tissue.The expression of miR144-3p in mouse cardiomyocytes was detected by Real-time PCR. Antinuclear factor (ANF), β-myosin heavy chain (β-MHC), actin α1 (Acta1) and histone deacetylase 2 (HDAC2) were detected by Western blotting in three groups. Results Compared with the control group, the interventricular septal thickness- diastolic(IVSd), interventricular septal thickness-systolic(IVSs), diastolic left ventricular posterior wall thickness(IVPWd), systolic left ventricular posterior wall thickness(IVPWs), ejection fraction(EF), cardiac weight index and left cardiac index of the model group and the transfection group were significantly higher, while systolic left ventricular diameter (LVDs) and diastolic left ventricular diameter(LVDd)were lower (P0. 05). Compared with the control group, the relative expression of miR144-3p in the model group and the transfection group was significantly higher than that in the model group (P<0. 05). Compared with the control group, the expression levels of antinuclear factor, β-myosin heavy chain, Actinα1 and histone deacetylase 2 in the model group and the transfected group were significantly higher (P<0. 05). Conclusion miR144-3p can aggravate cardiac hypertrophy by up-regulating HDAC2 and is expected to become a new therapeutic target.
ABSTRACT
To explore the changes in adrenomedullin (ADM) and receptor activity-modifying protein 2 (RAMP2) mRNA in myocardium and vessels in hypertension, a hypertensive rat model was prepared by administering L-NNA. Contents of ADM in plasma, myocardium and vessels were measured by radioimmunoassay (RIA). The levels of pro-ADM mRNA of myocardium and vessels were determined by competitive quantitative RT-PCR. The results showed that L-NNA induced hypertension and cardiomegaly. The ratio of heart to body weight increased by 35.5% (P<0.01). In hypertensive rats the ir-ADM in plasma, myocardium and vessels was increased by 80%, 72% and 57% (P<0.01), respectively compared with the control. The amounts of ADM mRNA in myocardium and vessels were increased by 50% and 109.2% (P<0.05), respectively, and the amounts of RAMP2 mRNA was increased by 132% and 87% (P<0.01), respectively, compared with control. The levels of ADM in myocardium and vessels were positively correlated with RAMP2 mRNA, the correlation coefficients were 0.741 and 0.885 (P<0.01), respectively. The results obtained indicate that in hypertensive rats, ADM is elevated in plasma, myocardium and ves-myocardium and vessel, and ADM and RAMP2 mRNA are up-regulated in myocardium and vessel. The ADM/RAMP2 system may play an important role in the pathogenesis of hypertension.
Subject(s)
Animals , Rats , Adrenomedullin , Metabolism , Cardiomegaly , Metabolism , Hypertension , Metabolism , Myocardium , Metabolism , Nitroarginine , Pharmacology , RNA, Messenger , Receptor Activity-Modifying Protein 2 , Metabolism , Reverse Transcriptase Polymerase Chain Reaction , Up-RegulationABSTRACT
The alterations of taurine transport and the expression of taurine transporter (TAUT) mRNA in myocardium and aortic wall were investigated in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. It was demonstrated that plasma taurine concentration and taurine release from myocardium and aortic wall in SHR were higher than those in WKY rats, whereas taurine content, taurine uptake and TAUT mRNA in myocardium and aortic wall of SHR were lower than those of WKY rats. In SHR, the maximal velocity (V(max)) of taurine transportation in myocardium and aortic wall was lower by 24% (P<0.05) and 35% (P<0.05) than that in WKY, their michaelis constants (Km) values were higher by 16% (P<0.05) and 39% (P<0.05), respectively. The results suggest that there is dysfunction of taurine transport in myocardium and aortic wall in SHR, which may be partly resulted from the decrease of TAUT activity and affinity, and down-regulation of TAUT gene expression.