Transcriptional coactivator EDF-1 is required for PPARgamma-stimulated adipogenesis.
Peroxisome proliferator-activated receptor-gamma (PPARgamma) is essential for adipogenesis. Since EDF-1 is a cofactor of PPARgamma, we investigated the molecular cross-talk between EDF-1 and PPARgamma in adipogenesis. While EDF-1 was not modulated during differentiation of 3T3-L1 cells, it co-immunoprecipitated with PPARgamma. Silencing EDF-1 by shRNAs inhibited the differentiation in adipocytes of 3T3-L1 cells, as detected by the staining of intracellular triglycerides and the expression of the PPARgamma target gene aP2. Accordingly, we found that anti-EDF-1 shRNAs decreased ligand dependent activation of PPARgamma in 3T3-L1 transiently transfected with a vector expressing luciferase under the control of a PPARgamma responsive consensus. To rule out that this inhibition is due to the concomitant downregulation of PPARgamma levels, we overexpressed PPARgamma in 3T3-L1 silencing EDF-1 and found a decrease of ligand dependent activation of PPARgamma, in spite of the high amounts of PPARgamma. These results demonstrate that EDF-1 is required for PPARgamma transcriptional activation during 3T3-L1 differentiation.
Leidi
Marzia
M
Department of Preclinical Sciences, Università di Milano Medical School, Via GB Grassi 74, Milan, Italy.
Mariotti
Massimo
M
Maier
Jeanette A M
JA
D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D050156:Adipogenesis / Q000235:genetics*; D000818:Animals; D002148:Calmodulin-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002454:Cell Differentiation / Q000235:genetics; D008024:Ligands; D051379:Mice; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D021381:Protein Transport; D034622:RNA Interference; D015533:Transcriptional Activation
D002148:Calmodulin-Binding Proteins; C485470:Edf1 protein, mouse; D008024:Ligands; D047495:PPAR gamma