Empagliflozin Attenuates Diabetic Cardiomyopathy via Inhibiting Cardiomyocyte Ferroptosis Through the USP7/NRF2 Signaling Pathway

AIMS: Diabetic cardiomyopathy (DbCM) typically manifests as diastolic dysfunction, and treating heart failure with preserved ejection fraction (HFpEF) is challenging. Empagliflozin (Empa), a sodium-glucose cotransporter 2 inhibitor, reduces hospitalization and mortality in patients with HFpEF and the risk of DbCM. However, the underlying molecular mechanisms and the specific targets remain largely unknown. RESULTS: Glutathione peroxidase 4 (GPX4) is a key enzyme that mitigates ferroptosis. Empa treatment improved cardiac function, upregulated GPX4 expression, and reduced ferroptosis in DbCM mice. The ferroptosis inducer erastin abolished the protective effects of Empa. Through database screening, we found that nuclear factor erythroid 2-related factor 2 (NRF2) plays an important role in ferroptosis in DbCM. NRF2 was expressed at lower levels in DbCM mice, and its expression significantly increased after Empa treatment. In NRF2-knockout mice, Empa failed to improve the cardiac function of DbCM mice, upregulate the expression of GPX4, and reduce ferroptosis. Moreover, Empa increased NRF2 levels by inhibiting ubiquitin-mediated degradation. A database search predicted that the stability of NRF2 may be regulated by ubiquitin-specific protease 7 (USP7). Immunoprecipitation assays demonstrated that USP7 interacted with NRF2 and mediated its deubiquitination, thereby stabilizing NRF2. Administration of the USP7 inhibitor P5091 abolished the effects of Empa, whereas the use of adeno-associated virus serotype 9 (AAV9)-NRF2 reversed the effects of P5091. INNOVATION AND CONCLUSION: 2022-SYDWLL-000213.