title: Constitutively active Stat5A and Stat5B promote adipogenesis.
abstract: OBJECTIVE
  The metabolic syndrome is an important social problem affecting many people in developed countries. Obesity is a leading cause of this syndrome, hence understanding molecular mechanisms underlying obesity is of prime importance for preventive medicine to develop novel methods to alleviate the corresponding social cost as well as for pharmaceutical companies to develop antimetabolic drugs.
  
  
  METHODS
  Since adipocytes play an important role in obesity, we explored the signaling pathways leading to differentiation of adipocytes. We used a preadipocyte cell line to monitor the differentiation of adipocytes, and virus-mediated gene transfer to assess the role of the transcription factor Stat5 in adipogenesis. Adipocyte differentiation was assessed by Northern blot and Western blot analyses as well as accumulation of fat droplets in cells. Promoter activity of the proadipogenic transcription factor peroxisome proliferator-activated receptor-gamma (PPARγ) was evaluated by luciferase assay.
  
  
  RESULTS
  Virus-mediated gene transfer of the constitutively active form of both Stat5A and Stat5B resulted in enhanced adipocyte differentiation in the absence of fetal bovine serum (FBS) as judged by expression of proadipogenic factors as well as accumulation of fat droplets in cells. Such a proadipogenic effect of Stat5 is, in part, mediated by its ability to enhance transcription of PPARγ, a master transcriptional regulator in adipogenesis.
  
  
  CONCLUSIONS
  The constitutively active form of Stat5A and Stat5B promoted adipocyte differentiation in the absence of FBS via induction of PPARγ.
authors: Department of Environmental Biology, School of Medicine, Hokkaido University, North 15 West 7, Kita-ku, Sapporo, 060-8638, Japan. hwakao@med.hokudai.ac.jp
authors: Hiroshi
authors: H
authors: Wakao
authors: Rika
authors: R
authors: Wakao
authors: Atsushi
authors: A
authors: Oda
authors: Hiroyoshi
authors: H
authors: Fujita
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000502:physiology*; D050156:Adipogenesis; D000818:Animals; D005312:Fetal Blood; D006801:Humans; D051379:Mice; D047495:PPAR gamma / Q000378:metabolism*; D050799:STAT5 Transcription Factor / Q000378:metabolism*; D014162:Transfection
chemical_list: D047495:PPAR gamma; D050799:STAT5 Transcription Factor; C494093:Stat5a protein, mouse; C494096:Stat5b protein, mouse