Phospholipase A2 is a Major Component of the Salt-Extractable Pool of Matrix Proteins in Adult Human Articular Cartilage (original) (raw)
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Clinical Chemistry and Laboratory Medicine, 2000
Both secretory and cytosolic phospholipase A 2 enzymes have been implicated in the pathogenesis of arthritis in animal models, but the exact expression patterns of the enzymes in diseased human joint tissue are uncertain. We investigated the messenger RNA expression of group IIa, IVa and V phospholipase A 2 and localized the presence of group IIa and IVa phospholipase A 2 at protein levels in articular cartilage from patients with rheumatoid arthritis, osteoarthritis and patients with non-arthritic joints. Both group IIa phospholipase A 2 messenger RNA and protein were detected in all samples independent of diagnosis, but were far more prominent in cartilage from rheumatoid arthritis samples. In cartilage with rheumatoid arthritis, the enzyme was detected both within the chondrocytes and in the extracellular matrix, whereas only few osteoarthritic cartilage samples showed positive staining in the matrix. In the cartilage matrix of non-arthritic controls, group IIa phospholipase A 2 was totally absent. Messenger RNA for the group IVa and V phospholipase A 2 was, except for one osteoarthritic cartilage sample, exclusively detected in rheumatoid arthritic cartilage. For group IVa phospholipase A 2 this was also confirmed at the protein level. These results suggest that each phospholipase A 2 enzyme has distinct roles in both healthy and diseased joint tissue, and that the diversity and amount of enzyme correlate with the grade of inflammation and disease severity.
Clinical chemistry and laboratory medicine : CCLM / FESCC, 2004
Both secretory and cytosolic phospholipase A 2 enzymes have been implicated in the pathogenesis of arthritis in animal models, but the exact expression patterns of the enzymes in diseased human joint tissue are uncertain. We investigated the messenger RNA expression of group IIa, IVa and V phospholipase A 2 and localized the presence of group IIa and IVa phospholipase A 2 at protein levels in articular cartilage from patients with rheumatoid arthritis, osteoarthritis and patients with non-arthritic joints. Both group IIa phospholipase A 2 messenger RNA and protein were detected in all samples independent of diagnosis, but were far more prominent in cartilage from rheumatoid arthritis samples. In cartilage with rheumatoid arthritis, the enzyme was detected both within the chondrocytes and in the extracellular matrix, whereas only few osteoarthritic cartilage samples showed positive staining in the matrix. In the cartilage matrix of non-arthritic controls, group IIa phospholipase A 2 was totally absent. Messenger RNA for the group IVa and V phospholipase A 2 was, except for one osteoarthritic cartilage sample, exclusively detected in rheumatoid arthritic cartilage. For group IVa phospholipase A 2 this was also confirmed at the protein level. These results suggest that each phospholipase A 2 enzyme has distinct roles in both healthy and diseased joint tissue, and that the diversity and amount of enzyme correlate with the grade of inflammation and disease severity.
Multiple Forms of Phospholipase A2 in Arthritic Synovial Fluid
The Journal of Biochemistry, 1989
Phospholipase A 2 (PLA 2) has been purified to homogeneity from human arthritic synovial fluid. The activity resolved into multiple peaks by preparative HPLC. The most abundant peak (A) was present in synovial fluid from patients with rheumatoid arthritis, osteoarthritis, and psoriatic arthritis. A second major peak (B) was variable and lower in relative abundance, but was distinguishable from peak A by its stimulated activity in the presence of either 0.5 M Tris or 0.1% sodium deoxycholate (DOC), in addition to its longer HPLC column retention time. Both peaks required Ca 2+ and showed optimal activity in DOC/ phosphatidylcholine (PC) mixed micelle assays between pH 8.0 and 9.0. Both peaks showed higher activity with PC as substrate than with PI, however peak A exhibited higher activity with PE than PC. Upon preparative SDS-polyacrylamide gel electrophoresis, both peaks of PLA 2 activity were resolved as proteins of approximately 14,000 Da. The N-terminal sequence obtained from purified peak A material matched that of a recent similar isolate (Hara et al. (1988) J. Biochem. 104, 326-328).
Journal of Biological Chemistry, 2003
1 The abbreviations used are: RA, rheumatoid arthritis; OA, osteoarthritis; MAPK, mitogen-activated protein kinase; ERK, extracellularregulated protein kinase; p38 MAPK, p38 mitogen-activated kinase; JNK, c-Jun NH 2-terminal kinase; MEK1/2, MAPK/ERK kinase; PGE 2 , prostaglandin E 2 ; AA, arachidonic acid; IL-1, interleukin-1; TNF-␣, tumor necrosis factor ␣; PLA 2 , phospholipase A 2 ; sPLA 2 , secretory PLA 2 ; cPLA 2 , cytoplasmic PLA 2 ; iPLA 2 , Ca2ϩ-independent PLA 2 ; BAPTA-AM, 1,2-bis(o-aminophenoxy)ethane-N,N,NЈ,NЈ-tetraacetic acid/acetoxymethyl ester; RB-2, Reactive Blue 2; BEL, bromoenol lactone; AACOCF3, arachidonyl trifluoromethyl ketone; P2Y, metabotropic receptors; PBS, phosphate-buffered saline; DN, dominant negative; ATP␥S, adenosine 5Ј-O-(thiotriphosphate); RT, reverse transcription.
Cartilage Matrix Protein: Expression Patterns in Chicken, Mouse, and Humana
Annals of the New York Academy of Sciences, 2008
Cartilage matrix protein is one of the most abundant noncollagenous extracellular proteins in cartilage. It consists of two von Willebrand Factor (vWF) A-domains that are separated by an EGF-like (epidermal growth factor) domain, and a heptadrepeat containing tail domain at the carboxyl terminal end (Frc;. l(A)). CMP has been shown to associate with the cartilage collagen fibrils that consists of collagen types 11, IX, and and with proteoglycan~.~ In primary chondrocyte culture, CMP forms a filamentous network that consists of both type 11 collagen dependent and independent filament^.^ Thus, it has been proposed that CMP may play an important role in
Matrix Biology, 2014
Thrombospondins (TSPs) are widely known as a family of five calcium-binding matricellular proteins. While these proteins belong to the same family, they are encoded by different genes, regulate different cellular functions and are localized to specific regions of the body. TSP-5 or Cartilage Oligomeric Matrix Protein (COMP) is the only TSP that has been associated with skeletal disorders in humans, including pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED). The pentameric structure of COMP, the evidence that it interacts with multiple cellular proteins, and recent reports of COMP acting as a 'lattice' to present growth factors to cells, inspired this review of COMP and its interacting partners. In our review, we have compiled the interactions of COMP with other proteins in the cartilage extracellular matrix and summarized their importance in maintaining the structural integrity of cartilage as well as in regulating cellular functions.