Osteoimmunology

This MedLibrary.org supplementary page on Osteoimmunology is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:

Osteoimmunology (όστέον, osteon from Greek, “bone”; immunitas from Latin, “immunity”; and λόγος, logos, from Greek “knowledge”) is the study of the interface between the skeletal system and the immune system, comprising the “osteo-immune system”. It is also the study of shared components and mechanisms between the two systems in vertebrates, including ligands, receptors, signaling molecules and transcription factors. Some medical conditions in which this field is particularly relevant are bone metastases, rheumatoid arthritis, osteoporosis, osteopetrosis, and periodontitis. Studies in osteoimmunology reveal relationships between molecular communication among blood cells and structural pathologies in the body.

Contents

System Similarities

The RANKL-RANK-OPG axis is an example of an important signaling system functioning both in bone and immune cell communication. RANKL is expressed on osteoblasts and activated T cells, whereas RANK is expressed on osteoclasts, and dendritic cells (DCs), both of which can be derived from myeloid progenitor cells. Surface RANKL on osteoblasts as well as secreted RANKL provide necessary signals for osteoclast precursors to differentiate into osteoclasts. RANKL expression on activated T cells leads to DC activation through binding to RANK expressed on DCs. OPG, produced by DCs, is a soluble decoy receptor for RANKL that competitively inhibits RANKL binding to RANK.

Crosstalk

The bone marrow cavity is important for the proper development of the immune system, and houses important stem cells for maintenance of the immune system. Within this space, as well as outside of it, cytokines produced by immune cells also have important effects on regulating bone homeostasis. Some important cytokines that are produced by the immune system, including RANKL, M-CSF, TNFa, ILs, and IFNs, affect the differentiation and activity of osteoclasts and bone resorption. During chronic inflammation, the balance of bone modeling and remodeling can be greatly affected, contributing to painful and/or visible disorders in bone metabolism.

See also

References

  • McInnes IB, Schett G (2007). "Cytokines in the pathogenesis of rheumatoid arthritis". Nat. Rev. Immunol. 7 (6): 429–42. doi:10.1038/nri2094. PMID 17525752. 
  • Takayanagi H (2007). "Osteoimmunology: shared mechanisms and crosstalk between the immune and bone systems". Nat. Rev. Immunol. 7 (4): 292–304. doi:10.1038/nri2062. PMID 17380158. 

Wikipedia content modification information:

  • This page was last modified on 24 July 2008, at 19:26.

Wikipedia Authorship and Review

Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.

Wikipedia Usage Guidelines

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Osteoimmunology".

The URL for this specific entry is:

All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.