title: Ascorbic acid enhances adipogenesis of 3T3-L1 murine preadipocyte through differential expression of collagens.
abstract: BACKGROUND
  Adipogenesis from preadipocytes into mature adipocyte is precisely coordinated by transcription factors such as CCAAT-enhancer-binding proteins (C/EBPs) and peroxisome proliferator-activated receptor γ (PPARγ), cytokines, and hormones, which is accompanied by extracellular matrix remodeling. Besides anti-oxidant activity, ascorbic acid (ASC) is participating in collagen biosynthesis and increase production and processing of collagens. Moreover, several studies demonstrated that ASC enhanced differentiation from preadipocytes into mature adipocytes.
  
  
  METHODS
  The adipogenic effect of ascorbic acid was evaluated in chemical induced 3T3-L1 by Oil Red O staining. This effect was elucidated by immunoblotting which detected the expression level of collagens and transcription factors in adipogenesis. The immunocytochemical determination of type I collagen was performed in 3T3-L1 adipocyte to show the change of extracellular matrix during adipogenesis.
  
  
  RESULTS
  In this study, Oil Red O staining in 3T3-L1 preadipocytes was increased dose-dependently by addition of ASC. These ASC-treated adipocytes increased collagen processing of α1(I) and α1(V) and expressed α1(VI) and α2(VI) collagens differentially. ASC also stimulated expression of C/EBPα and PPARγ, which is preceded by collagen enhancement. In addition, inhibition of ASC activity by ethyl-3,4-dihydroxybenzoate showed reduction of lipid accumulation by removal of large lipid droplets, not by inhibition of lipid production. This observation went with loss of α1(I) deposition on adipocyte surface, increase of α1(V) and α2(VI) collagens and decrease of C/EBPs.
  
  
  CONCLUSIONS
  Our findings imply that various actions of ASC on adipogenesis through differential collagen expression may provide diverse applications of ASC to adipose tissue technology.
authors: Byoungjae
authors: B
authors: Kim
authors: Kyung Min
authors: KM
authors: Choi
authors: Hong Soon
authors: HS
authors: Yim
authors: Department of Physiology, Korea University College of Medicine, Seoul 136-705, Republic of Korea. mingoolee@korea.ac.kr.
authors: Min-Goo
authors: MG
authors: Lee
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D050156:Adipogenesis / Q000235:genetics; D000818:Animals; D001205:Ascorbic Acid / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D001391:Azo Compounds; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D024042:Collagen Type I / Q000235:genetics* / Q000378:metabolism; D000090602:Collagen Type I, alpha 1 Chain; D024062:Collagen Type V / Q000235:genetics* / Q000378:metabolism; D024142:Collagen Type VI / Q000235:genetics* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005109:Extracellular Matrix / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D062385:Hydroxybenzoates / Q000494:pharmacology; D051379:Mice; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism
chemical_list: D001391:Azo Compounds; D022762:CCAAT-Enhancer-Binding Proteins; C530718:CEBPA protein, mouse; D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D024062:Collagen Type V; D024142:Collagen Type VI; D062385:Hydroxybenzoates; D047495:PPAR gamma; C018063:ethyl protocatechuate; C011049:oil red O; D001205:Ascorbic Acid