A novel pharmacological inhibitor of MAP4K4 activity protect against preclinical model of metabolic dysfunction-associated steatohepatitis

Metabolic dysfunction-associated steatohepatitis (MASH) is characterized by accumulation of fats in liver, chronic inflammation, hepatocytic ballooning, and fibrosis. In this study, glucosyl pyrrolo-pyrimidinone (GPPD), a newly synthesized pharmacological inhibitor of mitogen activated protein kinase kinase kinase kinase 4 (MAP4K4) was utilized to investigate significance of MAP4K4 signaling in MASH. To elucidate the effect of GPPD, wild-type (WT,C57BL6) mice were subjected to control diet (CD), high-fat high-fructose high-cholesterol diet (MASH diet, MD), and fed with MASH diet and treated with GPPD thrice a week for 30-week period. MAP4K4 immunoblotting and activity assay showed downregulation of MAP4K4 kinase activity without altering its expression. GPPD was able to mitigate hallmarks of MASH including steatosis, inflammation, fibrosis, and liver injury. Single-nuclei RNA sequencing revealed significant downregulation of calcium/calmodulin-dependent protein kinase II (CamKII). Subsequent immunoblotting confirmed that GPPD decreased expression and phosphorylation of CamKII in hepatocytes potentially conferring protection against steatohepatitis.