Up-regulation of miR-155 protects against chronic heart failure by inhibiting HIF-1α.

backgroundDespite a crucial role of miR-155 in human cancers, its function in heart failure (HF) is still under investigation. This study was designed to explore its association with HF.

methodsThe abdominal transverse aortic constriction (TAC) was adopted for establishment of mouse HF models. qRT-PCR and WB were adopted to detect the changes of miR-155, HIF-1α, Cle-caspase-3, BCL2 and Bax levels in myocardial cells and heart tissues. The changes of cardiac function were checked by ultrasound. Additionally, luciferase reporter gene was adopted for interaction analysis of miR-155 with HIF-1α, and

resultsMiR-155 in myocardial tissue of HF mice was significantly down regulated. In HF mice injected with agomiR-155, the up-regulation of miR-155 strongly improved cardiac function, and also significantly lowered the protein levels of apoptosis-associated markers, C-caspase-3 and Bax, but up regulated Bcl-2. Additionally, HIF-1α was identified as the direct target of miR-155. As expected, over-expression of HIF-1α greatly reversed the effects of agomiR-155 on cardiac function and the expression of apoptosis-associated markers in heart tissues of HF mice.

conclusionMiR-155 overexpression can suppress myocardial cell apoptosis through HIF-1α, and strongly alleviate the cardiac function damage in HF mice, indicating the potential of miR-155/HIF-1α axis to be a target for the diagnosis and therapy of HF.