Dapagliflozin Ameliorates Steatohepatitis by Restoring Ca 2+ Homeostasis and Hepatic Insulin Signaling

Background: Hepatic insulin resistance is a key driver of metabolic dysfunction-associated steatohepatitis (MASH) and is mechanistically linked to intracellular calcium (Ca2+) dysregulation. Sodium-glucose cotransporter 2 (SGLT2) inhibitors provide hepatoprotection, but their direct mechanisms have been debated because hepatocyte expression of SGLT2 is limited. We hypothesized that dapagliflozin restores hepatic insulin signaling by remodeling hepatocellular Ca2+ homeostasis. Methods: HepG2 cells with induced lipotoxicity and high-fat diet (HFD)-fed C57BL/6N mice were treated with dapagliflozin. Their insulin signaling, intracellular Ca2+ dynamics, and hepatic transcriptomic profiles were assessed using confocal microscopy, immunoblotting, and RNA sequencing. Results: Dapagliflozin was more effective than the other SGLT2 inhibitors in restoring insulin-stimulated protein kinase B (AKT) phosphorylation in HepG2 cells. Dapagliflozin attenuated cytosolic Ca2+ overload by restoring sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA2) and plasma membrane Ca2+ ATPase (PMCA2) expression and modulating Ca2+ influx-related proteins. It also significantly ameliorated hepatic steatosis, fibrosis, and insulin resistance in the HFD-fed mice without affecting their body weight. Transcriptomic profiling confirmed a decisive shift away from fibrotic and stress-related programs toward metabolic competence, as evidenced by the stable upregulation of Atp2a2 (SERCA2). Dapagliflozin also restored physiological postprandial insulin signaling and reactivated the AKT-glycogen synthase kinase-3 beta (GSK3β)-forkhead box O3a (FOXO3A) axis. Conclusion: Dapagliflozin has direct hepatoprotective effects that involve reprogramming the cellular Ca2+ influx-clearance balance. This pump-channel rebalancing alleviates the Ca2+-dependent biophysical barrier to insulin signaling and provides a molecular rationale for the weight-independent therapeutic efficacy of dapagliflozin in MASH.