Salt-inducible kinase inhibition promotes weight loss and improves the diastolic function of obesity-related heart failure with preserved ejection fraction in mice

BackgroundObesity negatively impacts cardiac function and is closely associated with heart failure with preserved ejection fraction (HFpEF). Salt-inducible kinases (SIKs) are critical regulators of energy metabolism and cardiovascular function. Small molecule SIK inhibitors have been developed but their effect in treating obesity-related HFpEF remains unexplored. We recently discovered that pharmacological SIK inhibition promotes the adipose tissue thermogenesis and mitochondrial biogenesis gene program. We reason that targeting SIKs to treat obesity-related complications would be beneficial for HFpEF. MethodsWe employed a preclinical HFpEF mouse model induced by two-hit stress of high-fat diet (HFD) and nitric oxide synthase (NOS) inhibition using L-NAME in drinking water. Eight-week-old C57BL/6J mice received a regular low-fat chow diet or HFD/L-NAME for 5 weeks and were treated with vehicle or a pan-SIK inhibitor YKL-05-099 (YKL) via daily intraperitoneal injection in the last 4 weeks. Body weight and parameters of adiposity, energy balance and glucose tolerance were assessed. Cardiovascular function was characterized by echocardiography and in vivo pressure-volume loop hemodynamic analysis. Myocardial transcriptomic data were analyzed to determine if changes in SIK gene expression are associated with human HFpEF. ResultsYKL treatment limits body weight gain mainly by reducing the fat mass in obese HFpEF mice. YKL-treated mice show better glucose tolerance, enhanced adipose tissue browning and decreased lipid deposition. YKL-treatment mice demonstrate preserved left ventricular (LV) ejection fraction, reduced LV filling pressure and improved diastolic function. Myocardial expression of SIK1, SIK2, and SIK3 mRNA is down-regulated in patients with HFpEF. However, higher SIK mRNA expression is associated with a subgroup of HFpEF patients that has a greater risk for HF hospitalization and/or death. ConclusionsTaken together, our study reveals a pathological role for SIKs in obesity-related HFpEF and suggests that pharmacological SIK inhibition would be a disease-modifying strategy for obese HFpEF, for which evidence-based therapy has been limited.