The Action of Cathepsin D in Human Articular Cartilage on Proteoglycans

Ai, Sapolsky; Rd, Altman; Jf, Woessner; Ds, Howell

doi:10.1172/jci107224

Cited by 88 publications

(49 citation statements)

References 40 publications

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“…Although one can theorize that this destruction of cartilaginous tissue occurs as a result of mechanical debridement, the more likely explanation is that at least some of the degradation is a result of enzymatic action. Prior studies from this and other laboratories have demonstrated locally synthesized proteases and other enzymes, principally lysosomal in origin, which have as their substrate the proteoglycan component of the articular cartilage and these appear to be significantly increased in quantity in osteoarthritis (1).…”

Section: Introductionmentioning

confidence: 82%

See 1 more Smart Citation

Collagenase and collagenase inhibitors in osteoarthritic and normal cartilage.

Ehrlich¹,

Mankin²,

Jones³

et al. 1977

J. Clin. Invest.

106

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A B S T R A C T In advanced osteoarthritis, all of the cartilaginous components are lost from the joint surface. Although mechanisms exist for proteoglycan degradation, there is not known to be any system for removal of the collagen. This study suggests that the loss of the collagen components may be a function of articular cartilage collagenase. The enzyme in normal human cartilage is bound to an inhibitor and appears to be present in very small amounts.Attempts to demonstrate collagenase activity in ground human articular cartilage or in its lysosomal fraction were unsuccessful. 7-Day cartilage tissue cultures also failed to demonstrate the presence of the enzyme; but the same culture fluid, incubated with trypsin, showed significant degradation of collagen, suggesting that trypsin destroyed the inhibitor.7-Day culture fluids were then chromatographed on a heparin-charged Sepharose 4B affinity column that had been activated with cyanogen bromide. This removed the inhibitor, and the chromatographed fluid from osteoarthritic cartilage released 42% of the incorporated counts of the collagen substrate, whereas normal cartilage released 10.1% and a trypsin control, 6.4%.Electrophoresis of the degradation products of the enzyme-collagen complex incubated at 37°C revealed breakdown was complete to small dialyzable fragments, while at 250C larger fragments were split off.

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Section: Introductionmentioning

confidence: 82%

“…It was noted that this reaction could proceed to complete digestion of the collagen where break-2 A a FIGURE 4 Electrophoresis of collagen (A) and collagen incubated with collagenase (B) from osteoarthritic cartilage at 250C. There are two main digestion products (1,2 Kang et al. (4).…”

Section: Discussionmentioning

confidence: 99%

Collagenase and collagenase inhibitors in osteoarthritic and normal cartilage.

Ehrlich¹,

Mankin²,

Jones³

et al. 1977

J. Clin. Invest.

106

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“…Proteoglycan degradation at the pericellular level (type A) suggests the possible involvement of acid proteases, since it has been postulated that cells might be able to produce an acid pH environment close to the cell surface (5). Cathepsins B and D, active at pH 6 and at pH 5, respectively, have been found in increased concentrations within OA cartilage (6,7). These cathepsins could be responsible for pericellular degradation.…”

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confidence: 99%

Proteoglycan‐degrading acid metalloprotease activity in human osteoarthritic cartilage, and the effect of intraarticular steroid injections

Pelletier¹,

Martel‐Pelletier²,

Cloutier³

et al. 1987

Arthritis & Rheumatism

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Cartilage samples from both the immediate and remote lesion areas were obtained from the tibia1 plateaus of 21 patients with osteoarthritis, and were subjected to histologic and enzymatic study. There was a frequent loss of pericellular metachromatic staining in the OA cartilage. Seven patients had received intraarticular injections of steroids, and in 21 % of those cartilage samples, a pericellular halo was seen. This halo was seen in 71 % of patients who had not received steroid injections. The total acid metalloprotease activity was increased more than twofold in specimens from OA lesions and in those samples graded moderate, as compared with age-matched control cartilages. These differences were greater when the specimens from patients who had received steroid therapy were excluded from the data. The cartilage specimens from steroid-treated patients were not significantly different from those of controls with respect to the enzyme activity in the lesions or in cartilage with moderate disease. The active form of the protease was suppressed by steroids. In samples from patients who did not receive steroid injections and who had a moderate grade of OA, a significantly elevated level of the active protease was present, as compared with control samples. Those samples graded moderate which came from patients who received steroid treatments showed no difference in the active protease level versus that of controls. Our results are consistent with the hypothesis that acid metalloprotease activity is involved in the degradation of the cartilage matrix in OA. Since the protease retains a significant fraction (40%) of its activity at neutral pH, its physiologic role might occur either at acid pH or at neutral pH. The halo surrounding the chondrocytes (the result of a local loss of proteoglycan) might be related to the action of this enzyme. Preliminary evidence has suggested that steroids reduce cartilage enzyme activity. Address reprint requests to J. p. Pelletier, MD, Unit6 des Maladies Rhumatismales, HGpital Notre-Dame, 1560 rue Sherbrooke Est, Montreal, Quebec, Canada H2L 4K8.vised form November 11, 1986. tent (1). Recent reports by Sachs et a1 (2) and Goldberg et (3) describe types Of changes in metachromatic staining. Type A is characterized by a lack of perkellular staining, so that a halo appearance is present around the lacunae. The remainder Of the intertenitorial matrix has norma] metachromatic staining. The

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“…Rapid assays for the estimation of enzyme units in the purification steps were performed by the method of Sapolsky et al (14); proteoglycan subunit from bovine nasal cartilage was used as substrate. A more exact assay for the further characterization of the enzyme was based on viscometry by means of microviscometers (15). The flow times were determined for native proteoglycan and for proteoglycan that had been completely degraded by cartilage protease.…”

Section: Methodsmentioning

confidence: 99%

Further characterization of a neutral metalloprotease isolated from human articular cartilage

Sapolsky

Howell

1982

Arthritis & Rheumatism

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The neutral metalloprotease extracted from 1,200 gm of human articular cartilage was purified 1,400‐ to 2,400‐fold by diethylaminoethyl‐ and carboxymethyl‐Sephadex chromatography. Disc electrophoresis and an isoelectric focusing method resolved the neutral enzyme activity into 4 bands. All bands had a similar amino acid analysis and a similar molecular weight by sodium dodecylsulfate electrophoresis and gel filtration: 24,000–27,000 daltons. The enzyme degraded proteoglycan subunit and proteoglycan aggregate to products with a sedimentation coefficient of 3S, but at low dilutions the enzyme produced 19.3S fragments. It is postulated that this protease may contribute to the development of osteoarthritis from within the cartilage matrix.

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The Action of Cathepsin D in Human Articular Cartilage on Proteoglycans

Cited by 88 publications

References 40 publications

Collagenase and collagenase inhibitors in osteoarthritic and normal cartilage.

Collagenase and collagenase inhibitors in osteoarthritic and normal cartilage.

Proteoglycan‐degrading acid metalloprotease activity in human osteoarthritic cartilage, and the effect of intraarticular steroid injections

Further characterization of a neutral metalloprotease isolated from human articular cartilage

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