MYD88 regulates the intercellular crosstalk landscape in MASH liver against metaflammation and metabolic disorder

Metabolic dysfunction-associated steatohepatitis (MASH) is the main cause of end-stage liver disease. We analyzed cell communication via ligand-receptor signaling at the single-cell level to elucidate cell-specific responses and spatial zonation in MASH. We screened and validated Myd88 hyperexpression in liver sinusoidal endothelial cells and liver capsular macrophages (LCM). We showed that Myd88 levels in the periportal endothelial cells of mice with MASH were higher than those in healthy controls, correlating significantly with dysregulation of capillarization markers in vivo. Moreover, Myd88 ⁺ LCM is a primary source of diverse signaling ligands involved in inflammatory cell recruitment during diet-induced MASH. CD24-Fc bound to the inhibitory receptor SIGLECG to significantly enhance SHP1 binding to MYD88, thereby inhibiting its activation and contributing to the restoration of immune-inflammatory homeostasis in the livers of diet-induced MASH mice. CD24-Fc improved amylin liver nonalcoholic steatohepatitis-induced MASH, which was partly abolished by AAV6-mediated Myd88 knockout in vivo. These findings underscore the central role of MYD88 in MASH etiology, and the specific targeting of MYD88 in liver sinusoidal endothelial cells and LCM may be a potential therapeutic approach to slow the progression of MASH.