TGFB1 and metabolic dysfunction-associated steatohepatitis: In NASH-induced liver, the expression of cleavage-resistant MerTK in Kupffer cells fosters secretion of transforming growth factor (TGF)-β1, which activates hepatic stellate cells (HSCs) and increases NASH-mediated fibrosis, suggesting that cleavage of MerTK antagonizes fibrogenesis [40].