Abstract
Diabetic cardiomyopathy (DCM) is one of the cardiovascular complications of diabetes mellitus independent of hypertension, coronary disease, and other heart diseases. The development of DCM is multifactorial and hard to detect at an early stage. Long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (Malat1) is emerging as a regulator of DCM, the underlying mechanism of its role in DCM has not been elaborated yet. In this study, we established a mouse DCM model via streptozocin injection as evidenced by cell hypertrophy and cell apoptosis of myocardial tissue, and found that Malat1 expression was upregulated in the myocardium in DCM mice. Meanwhile, elevated expression of pro-apoptotic factors p53, p21, cleaved caspase 3, cleaved caspase 9 and BAX, and down-regulation of anti-apoptotic BCL-2 were observed in DCM myocardium. We further investigated the effect of Malat1 on cardiomyocytes under high glucose condition by silencing Malat1 with its specific short-hairpin RNA. Like in vivo, expression of Malat1 in cardiomyocytes was notably raised, remarkable cell apoptosis and changes in apoptosis-related factors were also observed following high glucose treatment. Besides, we validated that Malat1 acted as a sponge of miR-181a-5p. Inhibition of miR-181a-5p could, at least partially, abolish Malat1 knockdown-induced alteration in cardiomyocytes. In addition, p53, a critical regulator of apoptosis, was validated to be a downstream target of miR-181a-5p. In summary, our findings reveal that Malat1 knockdown attenuates high glucose-induced cardiomyocyte apoptosis via releasing miR-181a-5p, and this mechanism may provide us with new diagnosis target of DCM.