title: Activation of proliferation and differentiation of dental follicle stem cells (DFSCs) by heat stress.
abstract: OBJECTIVE
  Adult stem cells (ASCs) remain in a slowly cycling/quiescent state under normal physiological conditions, but they can be awakened from this by certain factors, such as injury signals. Previously, our group has shown that dental follicle stem cells (DFSCs) appear to proliferate more rapidly than their non-stem cell counterparts at elevated temperatures. The study described here has aimed to (i) elucidate optimal temperature in which to culture DFSCs, (ii) determine whether elevated temperatures could enhance differentiation capability of DFSCs and (iii) characterize stem cell and osteogenic marker expression of DFSCs at elevated temperatures.
  
  
  METHODS
  DFSCs obtained from rat first molars were cultured at 37 (control), 38, 39, 40 and 41 ºC. Cell proliferation was evaluated by Alamar blue reduction assay and mean numbers of viable dissociated cells. Osteogenic differentiation was evaluated after 7 or 14 days osteogenic induction. Expression of selected marker genes was also assessed during proliferation and differentiation of the cells.
  
  
  RESULTS
  Increased cell proliferation was seen at heat-stress temperatures of 38º, 39º and 40 ºC. DFSCs revealed maximal osteogenesis when cultured at 39 and 40 ºC. Moreover, some stem cell and osteogensis-associated markers had elevated expression in heat-stress conditions.
  
  
  CONCLUSIONS
  Under determined heat-stress conditions, DFSCs increased their proliferation, osteogenic differentiation and expression of some marker genes. Thus, it is likely that elevated temperature could serve as a factor to activate adult stem cells.
authors.affiliation: Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, 70803, USA.
authors.forename: M
authors.initials: M
authors.lastname: Rezai Rad
authors.forename: G E
authors.initials: GE
authors.lastname: Wise
authors.forename: H
authors.initials: H
authors.lastname: Brooks
authors.forename: M B
authors.initials: MB
authors.lastname: Flanagan
authors.forename: S
authors.initials: S
authors.lastname: Yao
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D055398:Bone Morphogenetic Protein 3 / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D024081:Collagen Type IX / Q000235:genetics / Q000378:metabolism; D003795:Dental Sac / Q000166:cytology*; D015870:Gene Expression; D006358:Hot Temperature; D010012:Osteogenesis; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism; D013312:Stress, Physiological
chemical_list: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; C489249:Abcg2 protein, rat; D055398:Bone Morphogenetic Protein 3; D024081:Collagen Type IX; D011960:Receptors, Estrogen; D019009:Proto-Oncogene Proteins c-kit; D000469:Alkaline Phosphatase