title: Differential regulation of cadherin expression by osteotropic hormones and growth factors in vitro in human osteoprogenitor cells.
abstract: OBJECTIVE
  To examine if cadherins are expressed constitutively in human bone marrow stromal cells (hBMSC) and investigate the regulation of cadherin expression by various osteotropic hormones and local factors.
  
  
  METHODS
  Cadherin expression was examined in first passaged (secondary) hBMSC as well as in the conditionally-immortalized human osteoprogenitor cell line (hOP-7). Using a monoclonal antibody (MoAb C-1821) to a cytoplasmic domain common to all known cadherins (pan-cadherin MoAb), cadherins were immunolocalized in first passaged hBMSC as well as in hOP-7 cells. In addition, intense immunostaining for cadherin expression was associated with alkaline phosphatase (ALP) in nodules formed in the high density cultures of hOP-7 cells. Human E-cadherin (HECD) was specifically detected by Western blotting in extracts of untreated hBMSC using an anti-HECD MoAb 004FD.
  
  
  RESULTS
  Differential regulation of cadherin expression by various osteotropic hormones and local factors (parathyroid hormone, dexamethasone, estradiol, prostaglandin E2, basic fibroblast growth factor, and tumor necrosis factor-beta) was also observed. In addition, blocking cadherins with the MoAb C-1821 increased basal ALP activity and had an additive effect on 1, 25(OH) 2D3-induced ALP activity.
  
  
  CONCLUSIONS
  Cadherins are expressed in human osteoprogenitor cells and are involved in the osteogenic differentiation. The differential modulation of cadherin expression by osteotropic agents indicates that these agents may regulate osteoprogenitor cells through different cadherins and these cadherins may play different roles.
authors.affiliation: Arthritis Clinic and Research Center, People's Hospital, Medical Health Center, Peking University, Beijing 100044, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Liu
authors.forename: Jian-hao
authors.initials: JH
authors.lastname: Lin
authors.forename: Bi
authors.initials: B
authors.lastname: Zhang
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism*; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects*; D015820:Cadherins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D002117:Calcitriol / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D003907:Dexamethasone / Q000494:pharmacology; D015232:Dinoprostone / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D006801:Humans; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D015820:Cadherins; D016212:Transforming Growth Factor beta; D016222:Fibroblast Growth Factor 2; D003907:Dexamethasone; D000469:Alkaline Phosphatase; D002117:Calcitriol; D015232:Dinoprostone