title: Oleuropein and hydroxytyrosol inhibit adipocyte differentiation in 3 T3-L1 cells.
abstract: OBJECTIVE
  Oleuropein and hydroxytyrosol, which are antioxidant molecules found in olive leaves and oil, have been reported to exert several biochemical and pharmacological effects. These polyphenols are able to prevent low-density lipoprotein oxidation and protect cells against several diseases. Here, we studied the effect of these compounds on adipocyte differentiation in 3 T3-L1.
  
  
  METHODS
  To perform this study, 3 T3-L1 preadipocytes viability was analysed via Trypan blue and MTT assays, and triglycerides were stained with Oil Red O. Adipogenesis related genes expression were checked by RT-PCR and qRT-PCR. Also, cells counting and flow cytometry were used to analyse the mitotic cell cycle during the adipogenesis clonal expansion phase.
  
  
  RESULTS
  Oleuropein and hydroxytyrosol dose-dependently suppressed intracellular triglyceride accumulation during adipocyte differentiation without effect on cell viability. PPARγ, C/EBPα and SREBP-1c transcription factors and their downstream targets genes (GLUT4, CD36 and FASN) were down-regulated after treatment by oleuropein and hydroxytyrosol. At 200 and 300 μmol/L oleuropein or 100 and 150 μmol/L hydroxytyrosol, the greatest effect on the adipogenesis process was observed during the early stages of differentiation. Flow cytometry revealed both polyphenols to inhibit the division of 3T3-L1 preadipocytes during mitotic clonal expansion and cause cell cycle delay. Furthermore, oleuropein and its derivate hydroxytyrosol decreased the transcriptional activity of SREBP-1c in a stable transfected 3T3-L1 cell line.
  
  
  CONCLUSIONS
  These findings indicate that both compounds are able to prevent 3T3-L1 differentiation by inhibition of the mitotic clonal expansion and downregulation of the adipogenesis related genes.
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Riadh
authors.initials: R
authors.lastname: Drira
authors.forename: Shu
authors.initials: S
authors.lastname: Chen
authors.forename: Kazuichi
authors.initials: K
authors.lastname: Sakamoto
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism; D050156:Adipogenesis / Q000187:drug effects / Q000235:genetics; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D005434:Flow Cytometry; D057888:Iridoid Glucosides; D039823:Iridoids; D051379:Mice; D008938:Mitosis / Q000187:drug effects; D010626:Phenylethyl Alcohol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D011714:Pyrans / Q000008:administration & dosage / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014280:Triglycerides / Q000378:metabolism
chemical_list: D000975:Antioxidants; D057888:Iridoid Glucosides; D039823:Iridoids; D011714:Pyrans; D014280:Triglycerides; C005975:3,4-dihydroxyphenylethanol; C002769:oleuropein; D010626:Phenylethyl Alcohol