MicroRNA-15a/b are up-regulated in response to myocardial ischemia/reperfusion injury.
OBJECTIVE
Several studies have indicated that miR-15a, miR-15b and miR-16 may be the important regulators of apoptosis. Since attenuate apoptosis could protect myocardium and reduce infarction size, the present study was aimed to find out whether these miRNAs participate in regulating myocardial ischemia reperfusion (I/R) injury.


METHODS
Apoptosis in mice hearts subjected to I/R was detected by TUNEL assay in vivo, while flow cytometry analysis followed by Annexin V/PI double stain in vitro was used to detect apoptosis in cultured cardiomyocytes which were subjected to hypoxia/reoxygenation (H/R). Taqman real-time quantitative PCR was used to confirm whether miR-15a/15b/16 were involved in the regulation of cardiac I/R and H/R.


RESULTS
Compared to those of the controls, I/R or H/R induced apoptosis of cardiomyocytes was significantly increased both in vivo (24.4% ± 9.4% vs. 2.2% ± 1.9%, P < 0.01, n = 5) and in vitro (14.12% ± 0.92% vs. 2.22% ± 0.08%). The expression of miR-15a and miR-15b, but not miR-16, was increased in the mice I/R model, and the results were consistent in the H/R model.


CONCLUSIONS
Our data indicate miR-15 and miR-15b are up-regulated in response to cardiac I/R injury, therefore, down-regulation of miR-15a/b may be a promising strategy to reduce myocardial apoptosis induced by cardiac I/R injury.
Institute of Geriatric Cardiology, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853, China.
Li-Feng
LF
Liu
Zhuo
Z
Liang
Zhen-Rong
ZR
Lv
Xiu-Hua
XH
Liu
Jing
J
Bai
Jie
J
Chen
Chen
C
Chen
Yu
Y
Wang