PRKCD and metabolic dysfunction-associated steatohepatitis: Specifically, overloading free cholesterol induces the expression of sphingomyelin synthase 1 (SMS1) in hepatocytes, and the diacylglycerol (DAG) produced by SMS1 activates protein kinase Cδ (PKCδ) and NLR family CARD domain-containing protein 4 (NLRC4) inflammasome to induce pyroptosis, thus triggering the development of non-alcoholic steatohepatitis (NASH) 30.