Effect of miR-29a Inhibition on Ventricular Hypertrophy Induced by Pressure Overload

To investigate whether inhibition of miR-29a functioning prevents the hypertension-induced ventricular hypertrophy and fibrosis. Patients diagnosed with hypertension and left ventricular hypertrophy were recruited for the study. Serum levels of miR-29a were determined by RT-PCR. Levels of serum matrix metalloproteinase-9 (MMP-9), collagen type I and III (PINP and PIIINP) were determined by double-antibody enzyme-linked immunosorbent assay. Mouse model of transverse aortic constriction (TAC) was established. 7 days after surgery, TAC mice were injected intraperitoneally with antagomir miR-29a or vehicle once a day for 3 days. After 4 weeks of surgery, animals were sacrificed and cross-sections of the hearts were stained and evaluated for hypertrophy and fibrosis. The expression of the protein markers of hypertrophy and fibrosis was determined by immunoblotting. The serum level of miR-29a in hypertensive patients with left ventricular hypertrophy was significantly higher than those in patients with hypertension alone (p < 0.05). The levels of serum miR-29a were positively correlated with those of PINP, PIIINP, and MMP-9 (r = 0.58, 0.45, 0.66, respectively, p < 0.05). In mouse model of pressure overload, the antagomir miR-29a was found to significantly suppress the hypertrophy of cardiomyocytes and the expression of ANP and beta-MHC, the hypertrophy indices. Also, the ventricular fibrosis and expression of the marker proteins were blocked in antagomir treated mice. The inhibition of miR-29a was found to be effective in improving the ventricular remodeling and hypertrophy caused by pressure overload.