Aubrey C. Cantrell

Hypertension is a major risk factor for heart failure. Acetylation of p53 is known to regulate its activities. We have previously identified that p53 acetylation is required for cardiac remodeling in a mouse model of pressure overload-induced heart failure. Acetylation mutant p53 (p53aceKO) mice have been shown to have the ability to regulate SIRT3 KO-induced cardiac fibrosis. In the present study, we hypothesized that p53aceKO mice would exhibit cardiac protection and blunt cardiac fibrosis when subjected to Ang-II-induced hypertension. Control and p53aceKO mice received either a micro-osmotic pump implant administering Ang-II for 28 days or a sham procedure. Blood pressure was measured weekly, and echocardiography was performed every two weeks. Mice were euthanized and hearts were processed for histological analysis. While both control and p53aceKO mice receiving Ang-II exhibit increased systolic and diastolic blood pressures, control mice also demonstrate increases in ejection fraction and fractional shortening compared to the sham, while p53aceKO mice do not. Furthermore, control mice receiving Ang-II exhibit decreased left ventricular diameter and volume at end-systole and end-diastole, as well as thickening of both the anterior and posterior walls, while p53aceKO mice exhibit no significant changes in any of these parameters. Additionally, p53aceKO mice do not exhibit the Ang-II infusion-induced cardiac fibrosis seen in control mice treated with Ang-II. Mutation of p53 acetylation is protective against Ang-II infusion-induced cardiac fibrosis and dysfunction in mice. Acetylated p53 may, therefore, be a novel therapeutic target to address complications in the heart associated with hypertension.