Contribution of Nicotinamide-N-methyltransferase for SAM and 1-methylnicotinamide homeostasis in the AML12 hepatocyte cell line

Nicotinamide-N-methyltransferase (NNMT) is an enzyme that consumes S-adenosyl-methionine (SAM) and nicotinamide (NAM) to produce S-adenosyl-homocysteine (SAH) and 1-methylnicotinamide (MNAM), thereby affecting the quantity of these metabolites. How much NNMT contributes to these four metabolites depends on whether NNMT is a major consumer or producer of these metabolites, which varies among various cellular contexts. Yet, whether NNMT critically regulates these metabolites in the AML12 hepatocyte cell line has been unexplored. In this study, we aimed to investigate the effects of Nnmt RNAi on metabolism and gene expression in AML12 cell line.