ATF4 and metabolic dysfunction-associated steatohepatitis: In our MASH model, Kupffer cell depletion was associated with a decrease in the expression of markers of the unfolded protein response, shown by a decreased nuclear translocation of ATF4, decreased protein levels of GRP78, and normalized mRNA levels of both CHOP and p58IPK, a pathway implicated in cellular damage associated with inflammation and oxidative stress (Figure 4A–C).