title: Homeostatic levels of SRC-2 and SRC-3 promote early human adipogenesis.
abstract: The related coactivators SRC-2 and SRC-3 interact with peroxisome proliferator activated receptor γ (PPARγ) to coordinate transcriptional circuits to promote adipogenesis. To identify potential coactivator redundancy during human adipogenesis at single cell resolution, we used high content analysis to quantify links between PPARγ, SRC-2, SRC-3, and lipogenesis. Because we detected robust increases and significant cell-cell heterogeneity in PPARγ and lipogenesis, without changes in SRC-2 or SRC-3, we hypothesized that permissive coregulator levels comprise a necessary adipogenic equilibrium. We probed this equilibrium by down-regulating SRC-2 and SRC-3 while simultaneously quantifying PPARγ. Individual or joint knockdown equally inhibits lipid accumulation by preventing lipogenic gene engagement, without affecting PPARγ protein levels. Supporting dominant, pro-adipogenic roles for SRC-2 and SRC-3, SRC-1 knockdown does not affect adipogenesis. SRC-2 and SRC-3 knockdown increases the proportion of cells in a PPARγ(hi)/lipid(lo) state while increasing phospho-PPARγ-S114, an inhibitor of PPARγ transcriptional activity and adipogenesis. Together, we demonstrate that SRC-2 and SRC-3 concomitantly promote human adipocyte differentiation by attenuating phospho-PPARγ-S114 and modulating PPARγ cellular heterogeneity.
authors.affiliation: Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Sean M
authors.initials: SM
authors.lastname: Hartig
authors.forename: Bin
authors.initials: B
authors.lastname: He
authors.forename: Weiwen
authors.initials: W
authors.lastname: Long
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Buehrer
authors.forename: Michael A
authors.initials: MA
authors.lastname: Mancini
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D050156:Adipogenesis / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006706:Homeostasis / Q000235:genetics; D006801:Humans; D021621:Imaging, Three-Dimensional; D050155:Lipogenesis / Q000235:genetics; D051958:Nuclear Receptor Coactivator 2 / Q000235:genetics / Q000378:metabolism*; D056921:Nuclear Receptor Coactivator 3 / Q000235:genetics / Q000378:metabolism*; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D010766:Phosphorylation; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D015203:Reproducibility of Results
chemical_list: C498001:NCOA2 protein, human; D051958:Nuclear Receptor Coactivator 2; D047495:PPAR gamma; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C538866:NCOA3 protein, human; D056921:Nuclear Receptor Coactivator 3