Increased expression of activating factors in large osteoclasts could explain their excessive activity in osteolytic diseases

Autor: Johan N. M. Heersche, Morris F. Manolson, Divya Chandra, Diana P. Trebec, Azza Gramoun, Keying Li
Rok vydání: 2007
Předmět:
musculoskeletal diseases
medicine.drug_class
Receptor expression
Acid Phosphatase
Immunoblotting
Interleukin-1beta
Integrin
Osteoclasts
Receptor
Macrophage Colony-Stimulating Factor
Biochemistry
Bone resorption
Cell Line
Integrin alpha1beta1
Mice
Osteoclast
Extracellular
medicine
Animals
Receptors
Immunologic
Receptor
Molecular Biology
Tartrate-resistant acid phosphatase
Inflammation
Enzyme Precursors
Receptor Activator of Nuclear Factor-kappa B
biology
Reverse Transcriptase Polymerase Chain Reaction
Tartrate-Resistant Acid Phosphatase
Tumor Necrosis Factor-alpha
Chemistry
Arthritis
Macrophage Colony-Stimulating Factor
RANK Ligand
Cell Biology
Receptor antagonist
Cell biology
Isoenzymes
Interleukin 1 Receptor Antagonist Protein
medicine.anatomical_structure
Matrix Metalloproteinase 9
Immunology
biology.protein
Cytokines
Rabbits
Zdroj: Journal of Cellular Biochemistry. 101:205-220
ISSN: 1097-4644
0730-2312
Popis: Large osteoclasts (>or=10 nuclei) predominate at sites of pathological bone resorption. We hypothesized this was related to increased resorptive activity of large osteoclasts and have demonstrated previously that larger osteoclasts are 8-fold more likely to be resorbing than small osteoclasts (2-5 nuclei). Here we ask whether these differences in resorptive activity can be explained by differences in expression of factors involved in osteoclast signaling, fusion, attachment, and matrix degradation. Authentic rabbit osteoclasts and osteoclasts derived from RAW264.7 cells showed similar increases in c-fms expression (1.7- to 1.8-fold) in large osteoclasts suggesting that RAW cells are a viable system for further analysis. We found 2- to 4.5-fold increases in the expression of the integrins alpha(v) and beta(3), the proteases proMMP9, matMMP9 and pro-cathepsinK, and in activating receptors RANK, IL-1R1, and TNFR1 in large osteoclasts. In contrast, small osteoclasts had higher expression of the fusion protein SIRPalpha1 and the decoy receptor IL-1R2. The higher expression of activation receptors and lower expression of IL-1R2 in large osteoclasts suggest they are hyperresponsive to extracellular factors. This is supported by the observation that the resorptive activity in large osteoclasts was more responsive to IL-1beta, and that this increased activity was inhibited by the IL-1 receptor antagonist, IL-1ra. This increased responsiveness of large osteoclasts to IL-1 may, in part, explain the pathological bone loss noted in inflammatory diseases. The heterogeneity in receptor expression and the differential response to cytokines and their antagonists could prove useful for selective inhibition of large osteoclasts actively engaged in pathological bone loss.
Databáze: OpenAIRE
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