STI1 (SQOR inhibitor STI1) is a potent, specific, competitive inhibitor of human sulfide:quinone oxidoreductase (SQOR) with IC50 of 29 nM.
STI1 is a competitive inhibitor that binds with high selectivity to the coenzyme Q-binding pocket in SQOR, does not inhibit ETF:QO, complex I, complex II or complex III, DHODH (all IC50>300 uM).
STI1 exhibited very low cytotoxicity and attenuated the hypertrophic response of neonatal rat ventricular cardiomyocytes and H9c2 cells induced by neurohormonal stressors.
STI1 mitigated the development of cardiomegaly, pulmonary congestion, dilatation of the left ventricle, and cardiac fibrosis and decreased the pressure gradient across the aortic constriction in transverse aortic constriction (TAC) mice.
STI1 dramatically improved survival, preserved cardiac function, and prevented the progression to HFrEF by impeding the transition from compensated to decompensated left ventricle hypertrophy.