title: Thiazolidinediones cause compaction of nuclear heterochromatin in the pluripotent mesenchymal cell line C3H10T1/2 when inducing an adipogenic phenotype.
abstract: OBJECTIVE
  To characterize the nuclear changes induced in vitro by thiazolidinediones (TZDs) in a murine pluripotent mesenchymal cell line.
  
  
  METHODS
  The C3H10T1/2 cell line, which can differentiate either in osteoblast or in adipocyte, was cultured in the presence of pioglitazone (5 microM) or rosiglitazone (0.5 microM) for 6, 8 and 9 days (D). Quantitative real-time polymerase chain reaction analysis evaluated the expression of key genes of the adipocytic or osteoblastic differentiation (PPARgamma[peroxisome proliferatoractivated receptor gamma], Runx2 [runt-related transcription factor 2] and alkaline phosphatase). Cells were stained with Oil Red O for lipids, and chromatin was counter-stained with hematoxylin. Cells were photographed at x 1,000 magnification and analyzed with texture analysis software. Nuclear area, mean gray level and run-length parameters were calculated.
  
  
  RESULTS
  PPARgamma was significantly expressed from D6 (normalized ratio > 7) in TZD groups (ratio >27 at D9). No significant differences were found for either Runx2 or alkaline phosphatase expression versus control at D6 or D9. Cells cultured with TZDs began to differentiate into adipocytes with numerous lipid droplets which appeared at D6. Nuclear area decreased suddenly at D6 for both TZDs, and the mean gray level increased. Run-length parameters changed significantly due to chromatin compaction.
  
  
  CONCLUSIONS
  TZDs provoked differentiation of C3H10T1/2 into adipocytes, leading to inactivation of genes that were highly compacted into heterochromatin.
authors.affiliation: Research Group on Bone Remodeling and bioMaterials, IRIS-IBS, Institute of Biology of Health, University of Angers, Nantes, Le Mans, University Hospital of Angers, Angers Cedex, France. daniel.chappard@univ-angers.fr
authors.forename: Daniel
authors.initials: D
authors.lastname: Chappard
authors.forename: Héléne
authors.initials: H
authors.lastname: Marchand-Libouban
authors.forename: Marie Françoise
authors.initials: MF
authors.lastname: Moreau
authors.forename: Michel F
authors.initials: MF
authors.lastname: Baslé
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000502:physiology; D050156:Adipogenesis / Q000187:drug effects* / Q000502:physiology; D000469:Alkaline Phosphatase / Q000235:genetics; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects* / Q000473:pathology; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D006570:Heterochromatin / Q000187:drug effects* / Q000473:pathology; D007004:Hypoglycemic Agents / Q000494:pharmacology; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D051379:Mice; D047495:PPAR gamma / Q000235:genetics; D010641:Phenotype; D000077205:Pioglitazone; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000494:pharmacology*
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; D006570:Heterochromatin; D007004:Hypoglycemic Agents; D047495:PPAR gamma; C493716:Runx2 protein, mouse; D045162:Thiazolidinediones; D000077154:Rosiglitazone; D000469:Alkaline Phosphatase; D000077205:Pioglitazone