Research in our laboratory is focused on elucidating the mechanisms for insulin resistance and energy dysregulation in obesity and type 2 diabetes. In particular, we are investigating how adipocytes regulate systemic insulin sensitivity and whole body energy expenditure, using comprehensive approaches including molecular biology, animal physiology and metabolomic analyses.
Currently we are focusing on studying the roles of adipose nicotinamide N-methyltransferase (NNMT) in obesity and type 2 diabetes. NNMT methylates nicotinamide(vitamin B3) using s-adenosylmethionine (SAM) as a methyl donor. Nicotinamide is a precursor of NAD+, a key metabolite in energy metabolism. SAM regulates polyamine metabolism and epigenetic histone methylation. Using tissue-specific genetic mouse models as well as advanced cell culture system, we seek to determine the roles of NAD+, polyamines and histone methylation in NNMT-regulated insulin sensitivity and energy expenditure.