title: Cellular retinol-binding protein type I (CRBP-I) regulates adipogenesis.
abstract: Adipogenesis is governed by a well-documented cascade of transcription factors. However, less is known about non-transcription factors that govern early stages of adipogenesis. Here we show that cellular retinol-binding protein type I (CRBP-I), a small cytosolic binding protein for retinol and retinaldehyde, is specifically restricted to preadipocytes in white adipose tissue. The absence of CRBP-I in mice (CRBP-I-KO mice) leads to increased adiposity. Despite increased adiposity, CRBP-I-KO mice remain more glucose tolerant and insulin sensitive during high-fat-diet feeding. 3T3-L1 cells deficient in CRBP-I or mouse embryonic fibroblasts derived from CRBP-I-KO mice had increased adipocyte differentiation and triglyceride (TG) accumulation. This was due to increased expression and activity of PPAR gamma, while other transcription factor pathways in early and late differentiation remained unchanged. Conversely, the overexpression of CRBP-I in 3T3-L1 cells results in decreased TG accumulation. In conclusion, CRBP-I is a cytosolic protein specifically expressed in preadipocytes that regulates adipocyte differentiation in part by affecting PPAR gamma activity.
authors.affiliation: Department of Medicine and Institute of Human Nutrition, Columbia University, New York, New York 10032, USA.
authors.forename: C F
authors.initials: CF
authors.lastname: Zizola
authors.forename: S K
authors.initials: SK
authors.lastname: Frey
authors.forename: S
authors.initials: S
authors.lastname: Jitngarmkusol
authors.forename: B
authors.initials: B
authors.lastname: Kadereit
authors.forename: N
authors.initials: N
authors.lastname: Yan
authors.forename: S
authors.initials: S
authors.lastname: Vogel
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D050156:Adipogenesis / Q000502:physiology*; D050154:Adiposity; D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000502:physiology; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism; D005951:Glucose Tolerance Test; D007333:Insulin Resistance; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009765:Obesity / Q000378:metabolism / Q000473:pathology; D047495:PPAR gamma / Q000378:metabolism; D010641:Phenotype; D034741:RNA, Small Interfering / Q000235:genetics; D054840:Retinol-Binding Proteins, Cellular / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D014280:Triglycerides / Q000378:metabolism
chemical_list: D047495:PPAR gamma; D034741:RNA, Small Interfering; C518457:Rbp1 protein, mouse; D054840:Retinol-Binding Proteins, Cellular; D014280:Triglycerides