Forkhead transcription factor Foxo1 is essential  for adipocyte differentiation.
We analyzed the physiological role of forkhead box class O 1 (Foxo1) in adipocyte differentiation by suppressing Foxo1 mRNAwith siRNA specific for Foxo1.Mouse 3T3-L1 preadipocytes infected with an adenovirus expressing Foxo1-siRNA showed a marked decrease in lipid droplet formation when induced to differentiate into adipocytes. Adipocyte differentiation was most severely inhibited by exposing cells to Foxo1-siRNA before induction of differentiation. The incorporation of fluorescent-labeled glucose and fatty acid was significantly inhibited in cells deficient in Foxo1. RTPCR revealed that downregulation of Foxo1 decreased the expression of the transcription factors, PPAR-γ and C/EBP-α. By comparison, Foxo1-siRNA did not affect the expression of C/EBP-β or C/EBP-δ during the early period of adipocyte differentiation. These results indicate that Foxo1 plays an essential role in adipocyte differentiation, especially at the very early stage of terminal adipocyte differentiation.
Munekata
Keisuke
K
Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, Japan.
Sakamoto
Kazuichi
K
D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology* / Q000378:metabolism; D050156:Adipogenesis / Q000235:genetics; D000818:Animals; D019556:COS Cells; D002454:Cell Differentiation / Q000235:genetics*; D002522:Chlorocebus aethiops; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors / Q000037:antagonists & inhibitors / Q000502:physiology*; D050356:Lipid Metabolism / Q000235:genetics; D051379:Mice; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism
D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; C467200:Foxo1 protein, mouse; D012333:RNA, Messenger