The role of osteoclast-associated receptor in osteoimmunology

J Immunol. 2011 Jan 1;186(1):13-8. doi: 10.4049/jimmunol.1002483.


The term osteoimmunology is coined for molecular and cellular cross talk between the skeletal and immune system. Immunomodulatory signals have long been implicated as key regulators of bone metabolism. Recently, osteoclast-associated receptor (OSCAR), an IgG-like receptor, has been identified as an important osteoimmunological mediator. OSCAR expression in bone is highly conserved across different species, and the molecule is an important costimulatory receptor for osteoclast differentiation through activation of NFATc1. In humans, OSCAR is expressed by macrophages, monocytes, and monocyte-derived dendritic cells and modulates the response of the innate and adaptive immune systems by promoting cell activation and maturation, Ag presentation, and proinflammatory circuits. Human studies indicate that OSCAR may contribute to the pathogenesis and severity of osteoporosis and rheumatoid arthritis. In this paper, we review the structure-function relationship, expression pattern, and physiological role of OSCAR in osteoimmunology and summarize its potential implications for human diseases.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Bone Resorption / immunology*
  • Bone Resorption / metabolism
  • Bone Resorption / pathology
  • Bone and Bones / cytology
  • Bone and Bones / immunology*
  • Bone and Bones / metabolism
  • Cell Communication / immunology*
  • Humans
  • Osteoclasts / immunology*
  • Osteoclasts / metabolism
  • Osteoclasts / pathology
  • Receptor Cross-Talk / immunology*
  • Receptors, Cell Surface / biosynthesis
  • Receptors, Cell Surface / chemistry*
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / physiology*
  • Receptors, Immunologic / chemistry*
  • Receptors, Immunologic / physiology
  • Structure-Activity Relationship


  • OSCAR protein, human
  • Receptors, Cell Surface
  • Receptors, Immunologic