title: Secretome of primary cultures of human adipose-derived stem cells: modulation of serpins by adipogenesis.
abstract: Studies of adipogenic protein induction have led to a new appreciation of the role of adipose tissue as an endocrine organ. Adipocyte-derived "adipokines" such as adiponectin, leptin, and visceral adipose tissue-derived serine protease inhibitor (vaspin) exert hormone-like activities at the systemic level. In this study, we examined the secretome of primary cultures of human subcutaneous adipose-derived stem cells as an in vitro model of adipogenesis. Conditioned media obtained from four individual female donors after culture in uninduced or adipogenic induced conditions were compared by two-dimensional gel electrophoresis and tandem mass spectrometry. Over 80 individual protein features showing > or =2-fold relative differences were examined. Approximately 50% of the identified proteins have been described previously in the secretome of murine 3T3-L1 preadipocytes or in the interstitial fluid derived from human mammary gland adipose tissue. As reported by others, we found that the secretome included proteins such as actin and lactate dehydrogenase that do not display a leader sequence or transmembrane domain and are classified as "cytoplasmic" in origin. Moreover we detected a number of established adipokines such as adiponectin and plasminogen activator inhibitor 1. Of particular interest was the presence of multiple serine protease inhibitors (serpins). In addition to plasminogen activator inhibitor 1, these included pigment epithelium-derived factor (confirmed by Western immunoblot), placental thrombin inhibitor, pregnancy zone protein, and protease C1 inhibitor. These findings, together with the recent identification of vaspin, suggest that the serpin protein family warrants further proteomics investigation with respect to the etiology of obesity and type 2 diabetes.
authors.affiliation: Stem Cell Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA.
authors.forename: Sanjin
authors.initials: S
authors.lastname: Zvonic
authors.forename: Michael
authors.initials: M
authors.lastname: Lefevre
authors.forename: Gail
authors.initials: G
authors.lastname: Kilroy
authors.forename: Z Elizabeth
authors.initials: ZE
authors.lastname: Floyd
authors.forename: James P
authors.initials: JP
authors.lastname: DeLany
authors.forename: Indu
authors.initials: I
authors.lastname: Kheterpal
authors.forename: Amy
authors.initials: A
authors.lastname: Gravois
authors.forename: Ryan
authors.initials: R
authors.lastname: Dow
authors.forename: Angie
authors.initials: A
authors.lastname: White
authors.forename: Xiying
authors.initials: X
authors.lastname: Wu
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Gimble
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology; D050156:Adipogenesis / Q000502:physiology*; D000273:Adipose Tissue / Q000166:cytology* / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D018832:Molecular Chaperones / Q000235:genetics; D021381:Protein Transport; D020543:Proteome; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015843:Serpins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
chemical_list: D017077:Culture Media, Conditioned; D018832:Molecular Chaperones; D020543:Proteome; D012333:RNA, Messenger; D015843:Serpins