title: Paracrine-mediated differentiation and activation of human haematopoietic osteoclast precursor cells by skin and gingival fibroblasts.
abstract: OBJECTIVE
  Fibroblasts appear to modulate osteoclastogenesis, but their precise role in this process remains unclear. In this work, paracrine-mediated osteoclastogenic potential of different human fibroblasts was assessed.
  
  
  METHODS
  Fibroblast-conditioned media (CM) from foetal skin (CM1), adult skin (CM2) and adult gingiva (CM3) were used to promote osteoclastogenesis of osteoclast precursor cells. Cultures supplemented with macrophage-colony stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL) were used as controls.
  
  
  RESULTS
  All fibroblast cultures expressed FSP-1, M-CSF and RANKL and produced osteoprotegerin (OPG); gingival fibroblasts presented lowest expression of osteoclastogenic genes and higher production of OPG. All fibroblast CM were able to induce osteoclastogenesis. CM1 showed behaviour similar to positive controls, and slightly higher osteoclastogenic potential than CM, from adult ones. Gingival fibroblasts revealed lowest osteoclastogenic ability. Presence of anti-MCSF or anti-RANKL partially inhibited osteoclastogenesis promoted by CM, although the former antibody revealed higher inhibitory response. Differences among the osteoclastogenic effect of CM were noted, mainly in expression of genes involved in differentiation and activation of osteoclast precursor cells, c-myc and c-src, and less regarding functional related parameters.
  
  
  CONCLUSIONS
  Fibroblasts are able to induce osteoclastogenesis by paracrine mechanisms, and age and anatomical location affect this ability. Other factors produced by fibroblasts, in addition to M-CSF and RANKL, appear to contribute to observed osteoclastogenic potential.
authors.affiliation: Laboratório de Farmacologia e Biocompatibilidade Celular, Faculdade de Medicina Dentária, Universidade do Porto, Porto, Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Costa-Rodrigues
authors.forename: M H
authors.initials: MH
authors.lastname: Fernandes
mesh_terms: D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation; D002478:Cells, Cultured / Q000166:cytology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology*; D005786:Gene Expression Regulation; D005881:Gingiva / Q000166:cytology* / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D016173:Macrophage Colony-Stimulating Factor / Q000378:metabolism; D008954:Models, Biological; D010010:Osteoclasts / Q000166:cytology*; D053244:Osteoprotegerin / Q000378:metabolism; D019899:Paracrine Communication; D053245:RANK Ligand / Q000378:metabolism; D012867:Skin / Q000166:cytology*
chemical_list: D017077:Culture Media, Conditioned; D053244:Osteoprotegerin; D053245:RANK Ligand; D016173:Macrophage Colony-Stimulating Factor