title: Zinc-alpha2-glycoprotein, a lipid mobilizing factor, is expressed and secreted by human (SGBS) adipocytes.
abstract: Zinc-alpha2-glycoprotein (ZAG), a lipid mobilizing factor, is expressed in mouse adipose tissue and is markedly upregulated in mice with cancer cachexia. We have explored whether ZAG is expressed and secreted by human adipocytes, using SGBS cells, and examined the regulation of ZAG expression. ZAG mRNA was detected by RT-PCR in mature human adipocytes and in SGBS cells post-, but not pre-, differentiation to adipocytes. Relative ZAG mRNA levels increased rapidly after differentiation of SGBS cells, peaking at day 8 post-induction. ZAG protein was evident in differentiated adipocytes (by day 3) and also detected in the culture medium (by day 6) post-induction. The PPARgamma agonist rosiglitazone induced a 3-fold increase in ZAG mRNA level, while TNF-alpha led to a 4-fold decrease. Human adipocytes express and secrete ZAG, with ZAG expression being regulated particularly through TNF-alpha and the PPARgamma nuclear receptor. ZAG is a novel adipokine, which may be involved in the local regulation of adipose tissue function.
authors.affiliation: Neuroendocrine & Obesity Biology Unit, School of Clinical Sciences, University Clinical Departments, University of Liverpool, Liverpool L69 3GA, UK.
authors.forename: Yi
authors.initials: Y
authors.lastname: Bao
authors.forename: Chen
authors.initials: C
authors.lastname: Bing
authors.forename: Leif
authors.initials: L
authors.lastname: Hunter
authors.forename: John R
authors.initials: JR
authors.lastname: Jenkins
authors.forename: Martin
authors.initials: M
authors.lastname: Wabitsch
authors.forename: Paul
authors.initials: P
authors.lastname: Trayhurn
mesh_terms: D017667:Adipocytes / Q000737:chemistry / Q000378:metabolism*; D052242:Adiponectin; D000273:Adipose Tissue / Q000378:metabolism; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000235:genetics; D003907:Dexamethasone / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects / Q000235:genetics; D005786:Gene Expression Regulation; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D047495:PPAR gamma / Q000819:agonists / Q000502:physiology; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D000077154:Rosiglitazone; D029589:Seminal Plasma Proteins / Q000235:genetics / Q000378:metabolism*; D045162:Thiazolidinediones / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology / Q000502:physiology; D000090203:Zn-Alpha-2-Glycoprotein
chemical_list: D052242:Adiponectin; D007328:Insulin; D036341:Intercellular Signaling Peptides and Proteins; D015850:Interleukin-6; D008070:Lipopolysaccharides; D047495:PPAR gamma; D010455:Peptides; D012333:RNA, Messenger; D029589:Seminal Plasma Proteins; D045162:Thiazolidinediones; D014409:Tumor Necrosis Factor-alpha; D000090203:Zn-Alpha-2-Glycoprotein; C008287:lipid mobilizing substance; D000077154:Rosiglitazone; D003907:Dexamethasone; D009638:Norepinephrine