title: Cineromycin B isolated from Streptomyces cinerochromogenes inhibits adipocyte differentiation of 3T3-L1 cells via Krüppel-like factors 2 and 3.
abstract: OBJECTIVE
  3T3-L1 cells are preadipocytes and often used as a model for cellular differentiation to adipocytes; however, the mechanism of this differentiation is not completely understood even in these model cells. In this study, we sought to identify a unique anti-adipogenesis agent from microorganisms and to examine its mechanism of action to gain knowledge and create a tool and/or seed compound for anti-obesity drug discovery research.
  
  
  METHODS
  Screening for anti-adipogenesis agents from microorganisms was performed using a 3T3-L1 cell differentiation system, and an active compound was isolated. The inhibitory mechanism of the compound was investigated by measuring the expression of key regulators using quantitative real-time PCR and Western blot analysis.
  
  
  RESULTS
  The compound with anti-adipogenic activity in 3T3-L1 cells was identified as cineromycin B. Cineromycin B at 50 μg/mL suppressed intracellular lipid accumulation and the expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer binding protein alpha (C/EBPα), which are master regulators of adipocyte differentiation. Further investigations showed that cineromycin B increased significantly the mRNA expression of two negative regulators of adipocyte differentiation, Krüppel-like factor (KLF) 2 and KLF3, at an early stage of the differentiation. The results of siRNA transfection experiments indicated that cineromycin B is a unique adipocyte differentiation inhibitor, acting mainly via upregulation of KLF2 and KLF3, and these KLFs may play a role in the early stage of differentiation.
  
  
  CONCLUSIONS
  Cineromycin B inhibited adipocyte differentiation in 3T3-L1 cells mainly via upregulation of KLF2 and KLF3 mRNA expression at an early stage of the differentiation.
authors.affiliation: Graduate School of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan; Department of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga 525-8577, Japan. Electronic address: matsu-h@fc.ritsumei.ac.jp.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Matsuo
authors.affiliation: Graduate School of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kondo
authors.affiliation: Department of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kawasaki
authors.affiliation: Graduate School of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan; Department of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Imamura
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects* / Q000235:genetics; D051741:Kruppel-Like Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D007783:Lactones / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology*; D051379:Mice; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D013302:Streptomyces / Q000737:chemistry*; D015854:Up-Regulation / Q000187:drug effects* / Q000235:genetics
chemical_list: C498314:Klf2 protein, mouse; C529780:Klf3 protein, mouse; D051741:Kruppel-Like Transcription Factors; D007783:Lactones; D012333:RNA, Messenger; C000602311:cineromycin B
keywords: 3T3-L1 differentiation; Cineromycin B; GATA binding protein; Krüppel-like factor