Adipogenesis is a tightly regulated cellular differentiation process, in which the preadipocytes are transformed into differentiated adipocyte cells. Ikaros has been known as a cell cycle regulator on lymphoid and myeloid cell differentiation. However, the precise role of Ikaros in adipogenesis is still unclear. We investigated the role of Ikaros in vitro in adipocyte differentiation of preadipocyte cell line, 3T3-L1. Western blot analysis showed that Ikaros expression was significantly increased by 2 days in MDI-treated 3T3-L1 cells, whereas the expression of c-Myc was markedly decreased after 2 days. Oil red O staining revealed that inhibition of Ikaros by siRNA suppressed lipid droplet accumulation. In addition, knockdown of Ikaros resulted in re-entry of cell cycle progression from G1 phase as well as inhibition of p21 and p27 expression, cell cycle arrest proteins. In contrast, c-Myc expression was increased. Immunoprecipitation analysis demonstrated that the interaction of Ikaros and c-Myc was significantly enhanced in MDI-treated 3T3-L1 cells, suggesting that the interaction between Ikaros and c-Myc is required for adipogenesis. Taken together, our data suggest that Ikaros may play a critical role in adipocyte differentiation by negatively regulating c-Myc expression.
- Copyright © 2013 by The American Association of Immunologists, Inc.