title: OSBP-related proteins (ORPs) in human adipose depots and cultured adipocytes: evidence for impacts on the adipocyte phenotype.
abstract: Oxysterol-binding protein (OSBP) homologues, ORPs, are implicated in lipid homeostatic control, vesicle transport, and cell signaling. We analyzed here the quantity of ORP mRNAs in human subcutaneous (s.c.) and visceral adipose depots, as well as in the Simpson-Golabi-Behmel syndrome (SGBS) adipocyte cell model. All of the ORP mRNAs were present in the s.c and visceral adipose tissues, and the two depots shared an almost identical ORP mRNA expression pattern. SGBS adipocytes displayed a similar pattern, suggesting that the adipose tissue ORP expression pattern mainly derives from adipocytes. During SGBS cell adipogenic differentiation, ORP2, ORP3, ORP4, ORP7, and ORP8 mRNAs were down-regulated, while ORP11 was induced. To assess the impacts of ORPs on adipocyte differentiation, ORP3 and ORP8, proteins down-regulated during adipogenesis, were overexpressed in differentiating SGBS adipocytes, while ORP11, a protein induced during adipogenesis, was silenced. ORP8 overexpression resulted in reduced expression of the aP2 mRNA, while down-regulation of adiponectin and aP2 was observed in ORP11 silenced cells. Furthermore, ORP8 overexpression or silencing of ORP11 markedly decreased cellular triglyceride storage. These data identify the patterns of ORP expression in human adipose depots and SGBS adipocytes, and provide the first evidence for a functional impact of ORPs on the adipocyte phenotype.
authors.affiliation: Minerva Foundation Institute for Medical Research, Helsinki, Finland.
authors.forename: You
authors.initials: Y
authors.lastname: Zhou
authors.forename: Marius R
authors.initials: MR
authors.lastname: Robciuc
authors.forename: Martin
authors.initials: M
authors.lastname: Wabitsch
authors.forename: Anne
authors.initials: A
authors.lastname: Juuti
authors.forename: Marja
authors.initials: M
authors.lastname: Leivonen
authors.forename: Christian
authors.initials: C
authors.lastname: Ehnholm
authors.forename: Hannele
authors.initials: H
authors.lastname: Yki-Järvinen
authors.forename: Vesa M
authors.initials: VM
authors.lastname: Olkkonen
mesh_terms: D017667:Adipocytes / Q000166:cytology* / Q000378:metabolism*; D052242:Adiponectin / Q000378:metabolism; D000328:Adult; D015153:Blotting, Western; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D002478:Cells, Cultured; D019295:Computational Biology; D050556:Fatty Acid-Binding Proteins; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011987:Receptors, Steroid / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014280:Triglycerides / Q000378:metabolism; D000098825:Oxysterol Binding Proteins
chemical_list: D052242:Adiponectin; D002352:Carrier Proteins; D050556:Fatty Acid-Binding Proteins; C461064:OSBPL2 protein, human; C471934:OSBPL3 protein, human; D011987:Receptors, Steroid; D014280:Triglycerides; D000098825:Oxysterol Binding Proteins