Abstract 18872: Knockout of Card9 Rescues Transverse Aortic Constriction Induced Contractile Dysfunction in Isolated Cardiomyocytes

Introduction: CARD9, a scaffolding protein expressed in myeloid cells, regulates inflammatory cytokine secretion. Macrophage and neutrophil related inflammation is an underlying factor in cardiovascular disease and heart failure. Hypertension is a serious risk factor with a high prevalence (34%). Our preliminary results indicated CARD9 knockout is protective against transverse aortic constriction (TAC)-induced hypertrophy and fibrosis, and that it slows the progression of in-vivo cardiac dysfunction. Hypothesis: CARD9 knockout will reduce TAC-induced contractile dysfunction in isolated cardiomyocytes at 4 weeks post-TAC. Methods: C57BL/6 wild-type (WT) and CARD9-\- mice were assigned to transverse aortic constriction (TAC; n=6 each) or to control (CONT; n=3, 4 respectively). Systolic and diastolic parameters were assessed 4 weeks post-TAC in isolated cardiomyocytes. Western blots were performed for calcium flux regulators PLN and CAMKII, autophagy markers LC3BII/I and p62, and hypertrophy related proteins...