Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.23.5 (cathepsin D)
4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Approximately 20% of the radioactivity incorporated into the dentine collagen of unerupted bovine molars after reduction with tritiated sodium borohydride was recovered in a cyanogen bromide peptide fraction of Mr 61 000 following chromatography on agarose A5m. After rechromatography on agarose A1.5m, this fraction was resolved into ten components by gel isoelectric focusing. Of these components, nine (the most acidic) were tritiated and contained the reduced cross-links dihydroxylysinonorleucine and hydroxylysinonorleucine. The amino acid compositions were consistent with the identification of each of these components as alpha 2CB3,5 linked to one or two small peptides. By limited Edman degradation, with and without prior digestion with pyroglutamate aminopeptidase (EC 3.4.11.8), these small peptides were identified as alpha 1CB0,1 and alpha 2CB1, occurring in a ratio of approximately 2:1. Specific cleavage with cathepsin D revealed that all the cross-link was associated with the C-terminal one-third of the alpha 2 chain, thus fixing the displacement of the participating molecules at 4D. The content of the known reducible cross-links present in these peptides, calculated from the specific activity of the reductant, was sufficient to account for only 10--20% of the cross-linking actually found, suggesting that stabilization is mainly through nonreducible cross-links of as yet undetermined structure. By quantitative analysis of homoserine content and semiquantitative amino-terminal analyses, it was determined that virtually all of the alpha 2 chain of bovine dentine collagen is cross-linked in this manner. One cross-link per molecule in this location could made a major contribution to the mechanical stability of the insoluble collagen fibrils in this tissue.
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PMID:A major intermolecular cross-linking site in bovine dentine collagen involving the alpha 2 chain and stabilizing the 4D overlap. 747 Apr 54

An apparatus and test method were developed to determine the elastic stiffness and damping coefficient of human cartilage in compression. An underdamped, counterbalanced beam applied a sudden compressive force to a full-thickness cylindrical specimen of articular cartilage. The initial oscillatory response decayed to steady state creep after approximately 10 cycles of oscillation. The results were consistent with a Voigt phenomenological model with linear stiffness and damping terms. Standard dynamics analysis of the transient oscillatory response enabled the elastic stiffness to be determined from the frequency and the damping coefficient to be derived from the logarithmic decrement of the decay of the oscillations. The relationship between the mechanical properties and structure of cartilage was determined by treating specimens with two specific proteolytic enzymes. Digestion and removal of proteoglycans alone with cathepsin D caused the damping coefficient to decrease with no change in elastic stiffness. The action of leukocyte elastase on collagen caused a decrease in both damping coefficient and elastic stiffness. It was concluded that the collagen fibrils in cartilage largely control the elastic response while the viscous response is controlled largely by the hydrated proteoglycans. The effects of cartilage thickness was also examined and found to be inversely proportional to the elastic stiffness. It is suggested that this method could be used to uncouple elastic and viscous properties of other viscoelastic materials.
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PMID:The short-term compressive properties of adult human articular cartilage. 795 Aug 72

The localization of cathepsins B, D, and L was studied in rat osteoclasts by immuno-light and -electron microscopy using the avidin-biotin-peroxidase complex (ABC) method. In cryosections prepared for light microscopy, immunoreactivity for cathepsin D was found in numerous vesicles and vacuoles but was not detected along the resorption lacunae of osteoclasts. However, immunoreactivity for cathepsins B and L occurred strongly along the lacunae, and only weak intracellular immunoreactivity was observed in the vesicles and peripheral part of the vacuoles near the ruffled border. In control sections that were not incubated with the antibody, no cathepsins were found in the osteoclasts or along the resorption lacunae of osteoclasts. At the electron microscopic level, strong intracellular reactivity of cathepsin D was found in numerous vacuoles and vesicles, while extracellular cathepsin D was only slightly detected at the base of the ruffled border but was not found in the eroded bone matrix. Most osteoclasts showed strong extracellular deposition of cathepsins B and L on the collagen fibrils and bone matrix under the ruffled border. The extracellular deposition was stronger for cathepsin L than for cathepsin B. Furthermore cathepsins B and L immunolabeled some pits and part of the ampullar extracellular spaces, appearing as vacuoles in the sections. Conversely, the intracellular reactivity for cathepsins B and L was weak: cathepsin-containing vesicles and vacuoles as primary and secondary lysosomes occurred only sparsely. These findings suggest that cathepsins B and L, unlike cathepsin D, are rapidly released into the extracellular matrix and participate in the degradation of organic bone matrix containing collagen fibrils near the tip of the ruffled border.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Localization of cathepsins B, D, and L in the rat osteoclast by immuno-light and -electron microscopy. 802 81

Endometrial cancers have been considered to be less prevalent in Japan than in Western countries. However, with the increase in life expectancy, the Westernization of the Japanese diet, and changes in the hormonal environment, the prevalence of the disease has gradually increased even in our country. Similar increases in cancers of the breasts, lungs, colons, and ovaries have been noted in recent years. Much is still unknown regarding the pathogenesis and natural history of endometrial cancer. Although endometrial hyperplasia is considered to be a precancerous lesion of endometrial carcinoma, the relationship between those diseases has not been elucidated to the same degree as that between cervical cancer and cervical dysplasia, or carcinoma in situ. Research findings in genetic oncology have revealed that tumorigenesis involves a multi-step process. It is probable that activation of multiple genes, inactivation of anti-oncogenes, and disappearance of normal inhibitor genes occur in the process of the development of endometrial cancer. The purpose of this study is to elucidate the relationship between oncogenes and the development of endometrial cancer. In addition, the significance of endometrial hyperplasia as a clinical entity is also be evaluated. The roles played by oncogenes in endometrial cancers and endometrial hyperplasias were examined using the most recent molecular biological and immunohistochemical methods. Also, the differences in cellular proliferation and tissue invasiveness were discussed. Results obtained were as follows. Evaluation of cell proliferation (PCNA, FCM) revealed that there was no difference in proliferative activity between atypical hyperplasia and well differentiated adenocarcinoma. Evaluation of oncogene abnormalities (c-myc,c-erbB-2,K-ras,p53) revealed that the development of endometrial cancer was a multistep process involving several oncogenes, as it has been noted in the development of other cancers. Evaluation of extracellular matrix and related factors (cathepsin D, laminin, type IV collagen, tenascin, CD44) showed that tissue invasiveness differed between atypical hyperplasia and well differentiated adenocarcinoma.
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PMID:[Evaluation of the degree of biological behavior in endometrial hyperplasia and endometrial carcinoma: an investigation of proliferative activity, oncogene, and extracellular matrix]. 810 84

The effects of streptozotocin-induced diabetes on proteolytic activity and collagen biosynthesis in skin lesions in rats and on IGF-I binding proteins in their serum were evaluated. It was found that both collagen in intact skin and collagen biosynthesis in skin lesions were lower compared to control animals. Concurrently, there was an increase in proteolytic activity both in intact and lesioned skin. The livers and sera of diabetic animals also showed higher proteolytic activity. Inhibitors of cathepsin D (pepstatin and potato-derived inhibitor) prevent the decrease of collagen biosynthesis in the skin of diabetic rats. These observations indicate the co-existence of two phenomena in the investigated animals: an increase in proteolytic activity in tissues and a decrease in collagen biosynthesis. Furthermore, the diabetic rats showed significant changes in the composition of IGF-I serum binding proteins. The amount of high molecular weight binding proteins (HMW-BPs) was distinctly decreased, whereas the content of low molecular weight binding proteins (LMW-BPs) was significantly increased. Large amounts of LMW-BPs have been previously found in the sera of fasted and scorbutic animals. They are inhibitors of IGF-I activity. It is suggested that the increase in LMW-BP concentration in diabetic serum may be responsible for the inactivation of IGF-I resulting in decreased collagen biosynthesis. The role of proteolysis in the production of LMW-BPs in diabetic serum is discussed.
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PMID:Changes in IGF-binding proteins in rats with experimental diabetes. 816 86

An improved technique is described that addresses the problems of sensitivity, specificity, the use of hazardous radioactive equipment and time consumption in immunohistochemical labelling and double labelling of in situ hybridization of tissue specimens. It consists of a two-step protocol in which digoxigenin-uridine triphosphate (UTP) labelled riboprobes in the in situ hybridization step are visualized by the immunogold-silver staining method, and double labelling of tissue antigens is achieved by the application of an alkaline phosphatase-anti-alkaline phosphatase staining step. We tested this protocol using snap-frozen tissue sections of synovial tissue from patients with rheumatoid arthritis. The target mRNA was detected by perforin or cathepsin D riboprobes, the double labelling was performed using anti-collagen type IV and alpha-smooth muscle actin antibodies. It is concluded that, in comparison with an established three- to four-day double-labelling protocol used in many laboratories, this one-day combination is currently the most rapid assay of reliable quality for double labelling of in situ hybridization products and tissue antigens.
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PMID:A one-day double-labelling technique for tissue specimens: immunogold-silver staining for in situ hybridization combined with alkaline phosphatase-anti-alkaline phosphatase (APAAP) immunohistochemistry for antigens. 880 Dec 22

We inoculated the KLE human endometrial cancer, MCF-7 and ZR-75 human breast cancer, and PC-3 human prostate cancer cells into three-dimensional type I collagen gel system that contained uniformy dispersed MG-63 osteoblast-like cells. Then, we analyzed the morphological evidence of osteoblasts reaction, local invasion around the inoculated cancer cells and expression of the cathepsin D and urokinase-type plasminogen activator (uPA) around the sites of inoculation using immunocytochemistry. The prostate cancer cells produced morphological evidence of blastic reaction presented as an increased number of MG-63 osteoblasts and increase density of type I collagen around the sites of inoculation with PC-3 cells. The inoculated MCF-7 and ZR-75 cells decreased the density of type I collagen and number of osteoblasts and invaded the collagen gel around the sites of inoculation. The KLE endometrial cancer cells and cell-free media produced no reaction at the inoculation sites suggestive of cancer cell-specific interactions with osteoblasts in this system. The expression of uPA was remarkably higher at the inoculation sites of PC-3 cells as compared with those of the other cancer cells. Cathepsin D expression was higher at the sites of inoculation with KLE, MCF-7 and PC-3 cancer cells. MG-63 osteoblasts contained relatively low expression of uPA and cathepsin D. We conclude that this collagen gel system is a useful model for studying the morphological evidence of local invasion and osteoblasts reaction produced in response to local growth of metastatic cancer cell in vitro.
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PMID:Three-dimensional type I collagen gel system containing MG-63 osteoblasts-like cells as a model for studying local bone reaction caused by metastatic cancer cells. 891 85

Cells capable of de novo angiotensin (Ang)II generation in the heart remain unidentified. High-density angiotensin converting enzyme (ACE) binding has been localized to sites of high collagen turnover, such as heart valve leaflets and their valvular interstitial cells (VIC). VIC express ACE mRNA and their membrane-bound ACE utilizes AngI as substrate. Whether VIC also express angiotensinogen (Ao) and an aspartyl protease, and whether they generate AngI and II de novo, is presently unknown. We sought to address these questions in serum-deprived cultured VIC. Ao, renin and cathepsin D (Cat-D) mRNA expression was addressed by RT-PCR. Production of Ao, AngI and AngII peptides were measured in VIC-culture media by radioimmunoassay (RIA). Immunoreactive Cat-D was detected by immunofluorescein labeling and Western blotting. Cat-D and renin activities were determined by spectrofluorometric and autoradiographic methods and AngI generation by RIA. Results showed (a) expression of Ao and Cat-D both at mRNA and protein levels; (b) AngI and AngII peptides in culture media; (c) acceleration of AngII production by exogenous AngI (1 nmol/l), which was blocked by lisinopril (0.1 mumol/l); (d) that dexamethasone (0.1 mumol/l) increased AngII production; (e) a 46 kDa immunoreactive Cat-D protein by Western blotting; (f) aspartyl protease activity, using chromogenic and 125I-labeled Ao as substrates, inhibited by pepstatin-A; and (g) the absence of renin mRNA and activity. It is concluded that at both the mRNA and protein levels, cultured VIC express Ao and Cat-D, and can generate AngI and AngII peptides by the action of a non-renin protease Cat-D and ACE, respectively. VIC therefore appear to represent a constitutive nonendothelial cell found in adult rat heart valve leaflets, which are capable of de novo Ang peptide generation.
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PMID:Valvular interstitial cells express angiotensinogen and cathepsin D, and generate angiotensin peptides. 892 11

Chemotactic locomotion of fibroblasts requires extensive degradation of extracellular matrix components. The degradation is provided by a variety of proteases, including lysosomal enzymes. The process is regulated by cytokines. The present study shows that mannose 6-phosphate and insulin-like growth factor II (IGF-II) enhance fibroblast chemotaxis toward platelet-derived growth factor (PDGF). It is suggested that lysosomal enzymes (bearing mannose 6-phosphate molecules) are involved in chemotactic activity of the cells. The suggestion is supported by the observation that alpha-mannosidase and cathepsin D inhibitor-pepstatin are very potent inhibitors of fibroblast chemotaxis. Simultaneously, mannose 6-phosphate stimulates extracellular collagen degradation. The final step in collagen degradation is catalyzed by the cytosolic enzyme-prolidase. It has been found that mannose 6-phosphate stimulates also fibroblast prolidase activity with concomitant increase in lysosomal enzymes activity. The present study demonstrates that the prolidase activity in fibroblasts may reflect the chemotactic activity of the cells and suggests that the mechanism of cell locomotion may involve lysosomal enzyme targeting, probably through IGF-II/mannose 6-phosphate receptor.
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PMID:Fibroblast chemotaxis and prolidase activity modulation by insulin-like growth factor II and mannose 6-phosphate. 906 7

Scar tissue found at the site of myocardial infarction (MI) contains phenotypically transformed fibroblast-like cells termed myofibroblasts (myoFb). In injured cardiac tissue, autoradiography and immunolabeling have localized high density angiotensin (Ang) converting enzyme (ACE) and Ang II receptor binding to these cells, suggesting that they may regulate local concentrations of Ang II and transduce signals at this site. Ang II is known to modulate type I collagen gene expression of fibroblasts and myoFb, and to promote fibrous tissue contraction, each of which may contribute to tissue repair. It is unknown whether myoFb themselves generate Ang peptides de novo via expression of angiotensinogen (Ao), an aspartyl protease needed to convert Ao to Ang I, and ACE. We therefore isolated and cultured myoFb from 4-week-old scar tissue of the adult rat left ventricle with transmural MI. In cultured myoFb we found: (a) immunoreactive membrane-bound ACE, cytosolic cathepsin D (Cat-D), and AT, receptors by immunofluorescence and confocal microscopy, (b) mRNA expression for Ao, ACE, and Cat-D, but not renin, by reverse transcriptase-polymerase chain reaction, (c) production of Ang I and II in serum-free culture media; (d) absence of renin activity; (e) a time-dependent conversion of Ao to Ang I by myoFb cytosol, which was inhibited by pepstatin A, but not by renin inhibitor; and (f) significant increase in Ang II production (P < 0.05) by exogenous Ao and Ang I (10 nM), which was significantly blocked by lisinopril (0.1 microM: P < 0.05). Thus, cultured myoFb express requisite components and are able to generate Ang I and II de novo. In an autocrine and/or paracrine manner, Ang II may regulate myoFb collagen turnover and fibrous tissue contraction.
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PMID:Cultured myofibroblasts generate angiotensin peptides de novo. 920 23


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