265-OR: Exercise-Induced Lactylation of WDR41 Initiates Autophagy and Improves MASLD

Introduction and Objective: A sedentary lifestyle is associated with diabetes and MASLD (metabolic dysfunction-associated steatotic liver disease), but the causal mechanisms and preventive methods are not fully understood. Autophagy is a lysosomal degradation pathway robustly induced by physical exercise. This study is to determine how exercise activates autophagy systemically, and whether exercise-induced autophagy regulates hepatic glucose and lipid metabolism and plays a preventative role against MASLD. Methods: Animal exercise was carried out using a mouse treadmill. WDR41-depleted cells and mice, and cells expressing the WDR41 loss-of-lactylation mutant (WDR41K319R), were used to study the role and mechanism of WDR41 lactylation in autophagy activation and glucose and lipid metabolism. Liver samples from patients with MASLD, MASH or cirrhosis were collected and analyzed for expression and lactylation levels of WDR41. Statistical analysis was performed using one-way or two-way ANOVA with Tukey-Kramer test. Results: Via a proteomic screen we identified WDR41 as a pro-autophagy protein that undergoes lactylation under autophagy-inducing conditions, such as exercise. WDR41 is lactylated at lysine (K) 319, and lactylated WDR41 promotes autophagy initiation by directly binding to the autophagy proteins ATG13 and FIP200 and driving the ULK1 kinase complex assembly. Physiologically, WDR41, and WDR41 K319 lactylation, is essential for exercise-induced improvements in insulin sensitivity and lipid metabolism against excess lipid accumulation in the liver. A negative correlation between expression and lactylation of WDR41 was also discovered in patients with various hepatic metabolic dysfunctions. Conclusion: Exercise-induced WDR41 lactylation at K319 is an important regulatory mechanism by which exercise regulates autophagy and hepatic glucose and lipid metabolism. Lactylated WDR41 is a key player and potentially a biomarker of the pathogenesis of diabetes and MASLD. Disclosure C. He: None. Funding National Institutes of Health (R01 DK123447)