Integrin expression in human bone.
Integrins are a family of heterodimeric transmembrane glycoproteins that are known to mediate cell-cell and cell-matrix interactions. Members of the VLA (very late activation) family, which consists of beta 1 integrin in association with the VLA alpha chains (alpha 1-6), mediate adhesion of a wide range of cells to matrix proteins, such as fibronectin, collagen, and laminin, and may therefore be important for cell-matrix interactions in bone. Integrin expression in human bone was studied immunohistochemically using cryostat sections of fracture callus, tumor-associated reactive bone, and neonatal costochondral junctions, with a panel of well-characterized antibodies against beta 1-4 integrins, alpha 1-6 and alpha V integrins, and the alpha V beta 3 dimer (the classic vitronectin receptor). All cell types present in bone expressed beta 1 and alpha 5 integrins; a subpopulation of osteoblastic cells expressed alpha 4. The alpha V was uniformly expressed by osteoblasts but was heterogeneously expressed by osteocytes. Osteoclasts also expressed alpha 2, alpha V, and alpha V beta 3. These results demonstrate differential expression of a restricted range of integrins in bone. This supports the possibility that integrins may mediate the differing interactions of cells of the osteoblast and osteoclast lineages with the matrix of bone.
Department of Pathology, University of Edinburgh Medical School, Scotland.
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Hughes
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Salter
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Dedhar
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Simpson
D000918:Antibody Specificity; D001842:Bone and Bones / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D016023:Integrins / Q000096:biosynthesis*; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D010011:Osteocytes / Q000166:cytology / Q000378:metabolism*
D016023:Integrins