Background： MicroRNA-24 （miR-24） plays an important role in heart failure by reducing the efficiency of myocardial excitation-contraction coupling. Prolonged cardiac hypertrophy may lead to heart failure, but littl...Background： MicroRNA-24 （miR-24） plays an important role in heart failure by reducing the efficiency of myocardial excitation-contraction coupling. Prolonged cardiac hypertrophy may lead to heart failure, but little is known about the role of miR-24 in cardiac hypertrophy. This study aimed to preliminarily investigate the function of miR-24 and its mechanisms in cardiac hypertrophy. Methods： Twelve Sprague-Dawley rats with a body weight of 50 ± 5 g were recruited and randonlly divided into two groups： a transverse aortic constriction （TAC） group and a sham surgery group. Hypertrophy index was measured and calculated by echocardiography and hematoxylin and eosin staining. TargetScans algorithm-based prediction was used to search for the targets of miR-24, which was subsequently confirmed by a real-time polymerase chain reaction and luciferase assay, lmmunofluorescence labeling was used to measure the cell surface area, and 3H-leucine incorporation was used to detect the synthesis of total protein in neonatal rat cardiac myocytes （NRCMs） with the overexpression of miR-24. In addition, flow cytometry was performed to observe the alteration in the cell cycle. Statistical analysis was carried out with GraphPad Prism v5.0 and SPSS 19.0. A two-sided P 〈 0.05 was considered as the threshold for significance. Results： The expression of miR-24 was abnormally increased in TAC rat cardiac tissue （ t =-2.938, P 〈 0.05）. TargetScans algorithm-based prediction demonstrated that CDKN 1B （p27, Kip 1 ）, a cell cycle regulator, was a putative target of miR-24, and was confirmed by luci ferase assay. The expression of p27 was decreased in TAC rat cardiac tissue （t = 2.896, P 〈 0.05）. The overexpression of miR-24 in NRCMs led to the decreased expression of p27 （t = 4.400, P 〈 0.01 ）, and decreased G0/G 1 arrest in cell cycle and cardiomyocylc hypertrophy. Conclusion： MiR-24 promotes cardiac hypertrophy partly by affecting the cell cycle through down-regulation of p27 expression.展开更多
基金This work was supported by grant from National Natural Science Foundation of China （No. 91339105, and No. 81625001）.
文摘Background： MicroRNA-24 （miR-24） plays an important role in heart failure by reducing the efficiency of myocardial excitation-contraction coupling. Prolonged cardiac hypertrophy may lead to heart failure, but little is known about the role of miR-24 in cardiac hypertrophy. This study aimed to preliminarily investigate the function of miR-24 and its mechanisms in cardiac hypertrophy. Methods： Twelve Sprague-Dawley rats with a body weight of 50 ± 5 g were recruited and randonlly divided into two groups： a transverse aortic constriction （TAC） group and a sham surgery group. Hypertrophy index was measured and calculated by echocardiography and hematoxylin and eosin staining. TargetScans algorithm-based prediction was used to search for the targets of miR-24, which was subsequently confirmed by a real-time polymerase chain reaction and luciferase assay, lmmunofluorescence labeling was used to measure the cell surface area, and 3H-leucine incorporation was used to detect the synthesis of total protein in neonatal rat cardiac myocytes （NRCMs） with the overexpression of miR-24. In addition, flow cytometry was performed to observe the alteration in the cell cycle. Statistical analysis was carried out with GraphPad Prism v5.0 and SPSS 19.0. A two-sided P 〈 0.05 was considered as the threshold for significance. Results： The expression of miR-24 was abnormally increased in TAC rat cardiac tissue （ t =-2.938, P 〈 0.05）. TargetScans algorithm-based prediction demonstrated that CDKN 1B （p27, Kip 1 ）, a cell cycle regulator, was a putative target of miR-24, and was confirmed by luci ferase assay. The expression of p27 was decreased in TAC rat cardiac tissue （t = 2.896, P 〈 0.05）. The overexpression of miR-24 in NRCMs led to the decreased expression of p27 （t = 4.400, P 〈 0.01 ）, and decreased G0/G 1 arrest in cell cycle and cardiomyocylc hypertrophy. Conclusion： MiR-24 promotes cardiac hypertrophy partly by affecting the cell cycle through down-regulation of p27 expression.
