Exercise-induced lactylation in WDR41 initiates autophagy and improves fatty liver diseases

Excess lipid accumulation and a sedentary lifestyle are associated with metabolic dysfunction-associated fatty liver disease (MAFLD), but the causal mechanisms and preventive methods are not fully understood. Macroautophagy/autophagy is a lysosomal degradation pathway robustly induced by exercise and plays a key role in lipid metabolism. Understanding the mechanisms by which exercise activates autophagy and elicits metabolic benefits in the liver will provide important insights into the pathogenesis of MAFLD. Here, we discovered negative correlations between expression and lactylation of WDR41 (WD repeat domain 41) and pathogenesis of a series of human hepatic metabolic diseases. We found that WDR41 was a pro-autophagy protein that underwent lactylation in response to autophagy-inducing conditions, such as exercise. WDR41 was lactylated at lysine 319 (K319), a modification facilitated by LDHA (lactate dehydrogenase A) upon autophagy induction, and delactylated by SIRT2 (sirtuin 2). Lactylated WDR41 promoted autophagy initiation by directly interacting with the autophagy proteins ATG13 (autophagy related 13) and RB1CC1/FIP200 (RB1 inducible coiled-coil 1) and driving the ULK1 (unc-51 like autophagy activating kinase 1) complex assembly. Physiologically, WDR41 and WDR41^K319 lactylation, were important for exercise-induced improvements in insulin sensitivity and lipid metabolism against excess lipid accumulation in the liver. Thus, we demonstrated that WDR41 lactylation at K319 is an important regulatory mechanism by which exercise regulates autophagy and hepatic glucose and lipid metabolism.