CYP4A was regulated by PPARα in the lipid metabolism of nonalcoholic steatohepatitis [18], Cyp4A8 was up-regulated and high expression of CYP4A could decompose fatty acids into dicarboxylic fatty acids which damage mitochondrion function and generated more ROS [19], this may explain why fatty acid degradation pathway which Cyp4A8 involved in was over represented. This evidence concerns the gene PPARA and metabolic dysfunction-associated steatohepatitis.