Semicarbazide-sensitive amine oxidase activation promotes adipose conversion of 3T3-L1 cells

Semicarbazide-sensitive amine oxidase (SSAO) is an amine oxidase related to the copper-containing amine oxidase family. The tissular form of SSAO is l ocated at the plasma membrane, and is mainly expressed in vascular smooth m uscle cells and adipocytes. Recent studies have suggested that SSAO could a ctivate glucose transport in fat cells. In the present work, we investigate d the potential role of a chronic SSAO activation on adipocyte maturation o f the 3T3-L1 pre-adipose cell line. Exposure of post-confluent 3T3-L1 pre-a dipocytes to methylamine, a physiological substrate of SSAO, promoted adipo cyte differentiation in a time- and dose-dependent manner. This effect coul d be related to SSAO activation, since it was antagonized in the presence o f the SSAO inhibitor semicarbazide, but not in the presence of the monoamin e oxidase inhibitor pargyline. In addition, methylamine-induced adipocyte m aturation was mimicked by 3T3-L1 cell treatment with other SSAO substrates. Finally, the large reversion of methylamine action by catalase indicated t hat hydrogen peroxide generated by SSAO was involved, at least in part, in the modulation of adipocyte maturation. Taken together, our results suggest that SSAO may contribute to the control of adipose tissue development.