title: Bi-directional regulation between adiponectin and plasminogen activator-inhibitor-1 in 3T3-L1 cells.
abstract: BACKGROUND
  Adiponectin (APN) and plasminogen activator inhibitor-1 (Pai-1) are adipocytokines, and low levels of serum APN and high levels of PAI-1 are observed in obese patients. Moreover, both APN and Pai-1 are known to be involved in colorectal carcinogenesis. Recently, we demonstrated that serum Pai-1 levels are elevated in APN-deficient mice. We hypothesized that Pai-1 expression levels could be depressed by APN. Thus, we aimed to clarify the bi-directional regulatory mechanisms between APN and Pai-1.
  
  
  METHODS
  We investigated the expression levels of APN and Pai-1 during 3T3-L1 pre-adipocyte differentiation, and examined the role of AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor (PPAR)-γ on APN and Pai-1 expression at early and late differentiation stages.
  
  
  RESULTS
  In the early phase of differentiation, Pai-1 expression increased and APN slightly decreased. Reduction of Pai-1 or activation of PPARγ resulted in elevation of APN, and supplementation of APN with activation of AMPK resulted in reduction of Pai-1. In the late phase of differentiation, APN increased its expression and Pai-1 decreased. Supplementation of Pai-1 resulted in a slight reduction of APN.
  
  
  CONCLUSIONS
  It is suggested that APN and Pai-1 expressions are inversely-regulated. Understanding of the regulatory system between APN and Pai-1 may lead to finding novel methods for colorectal cancer prevention.
authors.affiliation: Division of Cancer Prevention Research, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan. mimutoh@ncc.go.jp.
authors.forename: Masami
authors.initials: M
authors.lastname: Komiya
authors.forename: Gen
authors.initials: G
authors.lastname: Fujii
authors.forename: Mami
authors.initials: M
authors.lastname: Takahashi
authors.forename: Misato
authors.initials: M
authors.lastname: Shimura
authors.forename: Nobuharu
authors.initials: N
authors.lastname: Noma
authors.forename: Satomi
authors.initials: S
authors.lastname: Shimizu
authors.forename: Wakana
authors.initials: W
authors.lastname: Onuma
authors.forename: Michihiro
authors.initials: M
authors.lastname: Mutoh
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000378:metabolism*; D052242:Adiponectin / Q000096:biosynthesis* / Q000235:genetics; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000235:genetics / Q000517:prevention & control; D005786:Gene Expression Regulation; D018507:Gene Expression Regulation, Developmental; D051379:Mice; D058258:Serpin E2 / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D052242:Adiponectin; D058258:Serpin E2; C511869:Serpine2 protein, mouse
keywords: AMPK; Adiponectin; PPAR; Pai-1; pre-adipocyte