2725-LB: CaMKK2 Preserves AMPK-Dependent Insulin Signaling by Limiting Lipid Peroxidation under Glucolipotoxic Stress in Type 2 Diabetes Mellitus

Introduction and Objective: Glucolipotoxic stress is a key driver of insulin resistance in type 2 diabetes mellitus (T2DM), in part through excessive lipid peroxidation and oxidative damage. Calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) is an upstream activator of AMP-activated protein kinase (AMPK) and plays a central role in cellular metabolic stress responses. However, whether CaMKK2 protects insulin signaling by modulating lipid peroxidation under diabetic conditions remains unclear. This study investigated the role of CaMKK2 in regulating AMPK-dependent insulin signaling under glucolipotoxic stress. Methods: T2DM was induced in wild-type and CaMKK2 knockout mice using a high-fat diet combined with low-dose streptozotocin (HFD+STZ). Glucose tolerance, insulin sensitivity, lipid profiles, and liver injury markers were assessed. Lipid peroxidation (4-HNE), macrophage infiltration, AMPK activation, and insulin signaling (IRS-1/AKT) were assessed in metabolic tissues. In parallel, CaMKK2 knockdown was performed in glucolipotoxic 3T3-L1 adipocytes to evaluate lipid accumulation, lipid peroxidation, and insulin signaling. Results: CaMKK2 deficiency aggravated glucose intolerance, insulin resistance, dyslipidaemia, and hepatic injury in HFD+STZ mice. Increased 4-HNE accumulation and inflammatory infiltration were observed in metabolic tissues. Mechanistically, CaMKK2 loss reduced AMPK phosphorylation and impaired IRS-1/AKT signaling. In glucolipotoxic adipocytes, CaMKK2 knockdown similarly enhanced lipid accumulation and lipid peroxidation while suppressing AMPK activation and insulin signaling. Conclusion: CaMKK2 preserves insulin sensitivity by limiting lipid peroxidation and maintaining AMPK-dependent insulin signaling under diabetic stress, highlighting CaMKK2 as a potential therapeutic target linking lipid peroxidation to insulin resistance in T2DM. Disclosure P. Tang: None. J. Chen: None. H. Li: None. Funding National Natural Science Foundation of China (82160165), Yunnan Xingdian Talent Support Program (XDYC-MY-2022-0015)