PTGS2 and metabolic dysfunction-associated steatohepatitis: mPGES-1-deficiency in hepatocytes on diet-induced hepatic TNF-α induction could be excluded because no genotype-specific differences in hepatic TNF-α mRNA levels were observed in livers of NASH-diet-fed mice with a hepatocyte-specific deficiency of cyclooxygenase 2 (Cox-2), the second key enzyme of induced PGE2 generation that acts upstream of mPGES-1 (preliminary unpublished data).