title: Expression of leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) on osteoclasts and its potential role in rheumatoid arthritis.
abstract: OBJECTIVE
  Leukocyte-associated immunoglobulin-like receptor-1 is an inhibitory receptor primarily expressed by immune cells. This study was undertaken to define the role of this molecule in osteoclast differentiation and rheumatoid arthritis.
  
  
  METHODS
  In vitro osteoclast assays were performed to characterize the role of Leukocyte-associated immunoglobulin-like receptor-1 in murine and human osteoclastogenesis. Human Leukocyte-associated immunoglobulin-like receptor-1 expression was assessed by immunohistochemistry staining in the synovium of patients with rheumatoid arthritis. The levels of soluble Human Leukocyte-associated immunoglobulin-like receptor-1 were determined by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  We found that multinucleated osteoclast formation from mouse bone marrow cells was inhibited by treatment with a monoclonal antibody against mouse Leukocyte-associated immunoglobulin-like receptor-1 in vitro. By immunohistochemistry, we found that Leukocyte-associated immunoglobulin-like receptor-1 was mainly expressed by macrophages in the inflamed synovial tissue of rheumatoid arthritis patients. In addition, serum and synovial fluid levels of soluble Leukocyte-associated immunoglobulin-like receptor-1 were higher in rheumatoid arthritis patients compared to healthy controls or osteoarthritis patients. Moreover, overexpression of Leukocyte-associated immunoglobulin-like receptor-1 in CD14+ monocytes from healthy volunteers also inhibited human osteoclastogenesis.
  
  
  CONCLUSIONS
  Collectively, these data demonstrate for the first time that Leukocyte-associated immunoglobulin-like receptor-1 inhibits osteoclastogenesis. Therefore, these results may have therapeutic implications for the treatment of rheumatoid arthritis.
authors.affiliation: Department of Physiology, Fourth Military Medical University, Xi'an, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yong
authors.initials: Y
authors.lastname: Ding
authors.forename: Yi
authors.initials: Y
authors.lastname: Huang
authors.forename: Chunmei
authors.initials: C
authors.lastname: Zhang
authors.forename: Jin
authors.initials: J
authors.lastname: Boquan
authors.forename: Zhuang
authors.initials: Z
authors.lastname: Ran
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001172:Arthritis, Rheumatoid / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D001854:Bone Marrow Cells / Q000473:pathology; D002454:Cell Differentiation / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D018950:Lipopolysaccharide Receptors / Q000097:blood; D008297:Male; D051379:Mice; D008875:Middle Aged; D010010:Osteoclasts / Q000166:cytology* / Q000187:drug effects; D053244:Osteoprotegerin / Q000502:physiology; D053245:RANK Ligand / Q000097:blood; D011971:Receptors, Immunologic / Q000032:analysis / Q000037:antagonists & inhibitors / Q000502:physiology*; D013583:Synovial Membrane / Q000378:metabolism
chemical_list: D018950:Lipopolysaccharide Receptors; D053244:Osteoprotegerin; D053245:RANK Ligand; D011971:Receptors, Immunologic; C108073:leukocyte-associated immunoglobulin-like receptor 1