- Meeting abstract
- Open Access
Overview: Destruction of the Extracellular Matrix in Rheumatoid Arthritis
Arthritis Research & Therapyvolume 1, Article number: S14 (1999)
A major cause of morbidity in rheumatoid arthritis (RA) is the destruction of the extracellular matrix (ECM) of cartilage, bone, and soft tissues of the joint. Proteolytic enzymes, such as the matrix metalloproteinases (MMPs) and the recently characterized and cloned aggrecanases with disintegrin domains, have a role in these destructive processes that result in loss of fibrillar (collagens) and nonfibrillar components of the ECM. MMPs, eg collagenases, cannot degrade the ECM of mineralized bone, but mechanisms require action of specialized cells (osteoclasts) generated from hemopoietic precursors in marrow and in the inflammatory cell mass. Ligands, which increase bone resorption, initiate osteoclast generation by acting on mesenchymal cells (fibroblasts, stromal cells, and osteoblasts) to induce cell-bound osteoclast differentiation factor (ODF). ODF in turn binds to a receptor (RANK) on osteoclast precursors and, with M-CSF, generates active osteoclasts. Another factor, osteoprotegerin (OPG), binds to ODF (also known as OPGL [ligand]) and inhibits osteoclastogenesis. A potent inducer of ODF is parathyroid hormone-related peptide (PTHrP); receptors for PTH/PTHrP are found on RA synovial fibroblasts, in culture, and by in situ hybridization, and PTH is produced by RA synovium through the action of inflammatory cytokines. There is evidence derived from studies in animal models that the action of collagenase produced by mesenchymal cells is required for PTH/PTHrP-induced osteoclast generation. Delineation of the precise function of the ligands and proteinases described would help in designing therapy to prevent or retard the focal bone erosions and more diffuse bone loss of RA.
Funk JL, Cordaro LA, Wei H, Benjamin JB, Yocum DE: Synovium as a source of increased amino-terminal parathyroid hormone-related protein expression in rheumatoid arthritis. A possible role for locally produced parathyroid hormone-related protein in the pathogenesis of rheumatoid arthritis. J Clin Invest. 1998, 101: 1362-1371.
Kohno H, et al: Synovial fluids from patients with osteoarthritis and rheumatoid arthritis contain high levels of parathyroid hormone-related peptide. J Bone Miner Res. 1997, 12: 847-854.
Kotake S, et al: IL-17 in synovial fluids from patients with rheumatoid arthritis is a potent stimulator or osteoclastogenesis. J Clin Invest. 1999, 103: 1345-1352.
Yoshida T, et al: Production of parathyroid hormone-related peptide by synovial fibroblasts in human osteoarthritis. FEBS Lett. 1998, 433: 331-334. 10.1016/S0014-5793(98)00940-5.
Krane SM, Zhao W: Collagenase in embryonic development and postnatal remodeling of connective tissues. In Collagenases. Edited by Hoeffler W. Austin: RG Landes Co. 1999, 171-187.
Shima YH, et al: Osteoclast differentiation factor is a ligand for osteoprotegerin/osteoclastogenesis-inhibitory factor and is identical to TRANCE/RANKL. Proc Natl Acad Sci USA. 1998, 95: 3597-3602. 10.1073/pnas.95.7.3597.
Hsu H, et al: Tumor necrosis factor receptor family member RANK mediates osteoclast differentiation and activation induced by osteoprotegerin ligand. Proc Natl Acad Sci USA. 1999, 96: 3540-3545. 10.1073/pnas.96.7.3540.
Suda T, et al: Modulation of osteoclast differentiation and function by the new members of the tumor necrosis factor receptor and ligand families. Endocr Rev. 1999, 20: 345-357. 10.1210/er.20.3.345.
Nagase H, Woessner JF: Matrix metalloproteinases. J Biol Chem. 1999, 274: 21491-21494. 10.1074/jbc.274.31.21491.
Zhao W, Byrne MH, Boyce BF, Krane SM: Bone resorption induced by parathyroid hormone is strikingly diminished in collagenase-resistant mutant mice. J Clin Invest. 1999, 103: 517-524.
Gravallese EM, Harada Y, Wang JT, Gorn AH, Thornhill TS, Goldring SR: Identification of cell types responsible for bone resorption in rheumatoid arthritis and juvenile rheumatoid arthritis. Am J Pathol. 1999, 152: 943-951.