title: Involvement of tazarotene-induced gene 1 in proliferation and differentiation of human adipose tissue-derived mesenchymal stem cells.
abstract: OBJECTIVE
  Mesenchymal stem cells (MSC) have both self-renewal and multilineage differentiation potential, and bone marrow-derived MSC have been applied for tissue regeneration and repair. Although adipose tissue-derived MSC (ASC) have emerged as an alternative cell source, little information is available regarding the biologic difference between ASC derived from visceral and subcutaneous fat. Therefore, we aimed to compare the proliferation and gene expression profile of cultured human visceral ASC (VASC) and subcutaneous ASC (SASC), and to identify a novel gene involved in proliferation and differentiation of ASC.
  
  
  METHODS
  We performed microarray analysis of cultured VASC and SASC, and investigated the role of tazarotene-induced gene 1 (TIG1), a most differentially expressed gene, in the proliferation and differentiation of ASC.
  
  
  RESULTS
  SASC proliferated faster than VASC for over 10 passages, and TIG1 expression was consistently up-regulated in VASC of humans, rats and mice. Overexpression of the TIG1 gene in human SASC inhibited cell proliferation, whereas knockdown of TIG1 expression by siRNA promoted cell proliferation. In addition, overexpression of the TIG1 gene in SASC enhanced their differentiation into adipocytes, and promoted up-regulation of peroxisome proliferators-activated receptor gamma and CCAAT/enhancer binding protein alpha. On the other hand, TIG1 overexpression in SASC inhibited their differentiation into osteocytes and the expression of osteocalcin.
  
  
  CONCLUSIONS
  TIG1 plays an important role in regulating proliferation and differentiation of ASC.
authors.affiliation: Department of Regenerative Medicine and Tissue Engineering, National Cardiovascular Center Research Institute, Osaka, Japan. shunpou@hotmail.com
authors.forename: S
authors.initials: S
authors.lastname: Ohnishi
authors.forename: K
authors.initials: K
authors.lastname: Okabe
authors.forename: H
authors.initials: H
authors.lastname: Obata
authors.forename: K
authors.initials: K
authors.lastname: Otani
authors.forename: S
authors.initials: S
authors.lastname: Ishikane
authors.forename: H
authors.initials: H
authors.lastname: Ogino
authors.forename: S
authors.initials: S
authors.lastname: Kitamura
authors.forename: N
authors.initials: N
authors.lastname: Nagaya
mesh_terms: D000273:Adipose Tissue / Q000166:cytology*; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D049109:Cell Proliferation; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000502:physiology*; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010011:Osteocytes / Q000166:cytology; D051381:Rats; D011917:Rats, Inbred Lew; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D008565:Membrane Proteins; C452562:RARRES1 protein, human