ACER3 and metabolic dysfunction-associated steatohepatitis: Immunostaining revealed that 4-HNE was detected mostly in steatotic hepatocytes in NASH livers from Acer3−/− and Acer3+/+ mice (Fig. 4b) and that the number of hepatocytes positive for staining of 4-HNE was significantly reduced in Acer3−/− mice compared to Acer3+/+ mice (Fig. 4c).