Cardiomyopathy Progression Due to Overexpression of miRNA- 322/503

Dilated cardiomyopathy is the leading cause of death among heart disease patients. It is characterized by a decrease in blood flow through the heart due to enlargement and weakness of the left ventricle. The miRNA, mir-322/503, was found to be increased in expression in dilated cardiomyopathy. Our lab has found that overexpression of miRNA- 322/503 in the heart using a doxycycline induced mouse model, leads to heart failure that exhibits characteristics of dilated cardiomyopathy. The main objective of this research was to monitor this heart failure progression over time. In vivo mice models were given a doxycycline diet for a month and body weight was monitored. Heart specific tissues were collected at days 0, 7, 14, 21 and 28 and stained with H&E stain. Heart stress markers were analyzed using qPCR. We found overexpression of miRNA- 322/503 leads to body weight loss, loss of cardiac function through dilation of ventricular chambers and wall thinning, increase in stress markers ANP (Atrial natriuretic peptide) and BNP (Brain natriuretic peptide), and a decrease in α-MHC (Myosin heavy chain).