Combined inhibition of autophagy protein 5 and galectin-1 by thiodigalactoside reduces diet-induced obesity through induction of white fat browning.

Our previous study demonstrated that thiodigalactoside (TDG) ameliorates obesity by targeted inhibition of galectin-1 (GAL1). Here, for the first time, we report the unexpected role of GAL1 and ATG5 inhibition by TDG in lipid metabolism. Core thermogenic marker proteins and genes were highly induced in white adipose tissue (WAT) of rats fed a high fat diet (HFD) and TDG, resulting in the significant development of brown fat-like adipocytes in inguinal WAT. TDG treatment reduced weight gain and fat mass as well as activated brown adipose tissue (BAT) in HFD-fed rats. TDG also reduced protein levels of LC3-II and increased protein levels of P62, suggesting its possible role in suppression of autophagy. Combined inhibition of GAL1 and ATG5 by TDG treatment protected rats against both HFD-induced adipogenesis as well as lipogenesis, as evidenced by suppression of CCAAT/enhancer-binding protein alpha, peroxisome proliferator-activated receptor gamma and fatty acid synthase. In conclusion, the present findings suggest that TDG plays a role in browning and lipid catabolism by combined inhibition of GAL1 and ATG5 and thus may have potential therapeutic implications in the regulation of energy homeostasis via its action in WAT. © 2017 IUBMB Life, 69(7):510-521, 2017.