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)

Alveolar macrophages are thought to play an important role in ongoing tissue breakdown and repair processes in the normal lung. The secretion and regulation of cathepsin D (important for the final breakdown of collagen) and fibronectin (involved in the healing process) in human peripheral blood monocytes (PBM) and pulmonary alveolar macrophages (PAM) were investigated. Cathepsin D enzyme activity was measured by quantitating the TCA-soluble fragments of [3H]hemoglobin. Freshly isolated PBM contained less cell-associated cathepsin D activity than did freshly isolated PAM (314 +/- 35 micrograms/10(6) cells vs 381 +/- 35 micrograms/10(6) cells, respectively). After 7-10 days in culture, cell-associated enzyme levels in both PBM and PAM were significantly increased (P less than 0.001 for PBM; P less than 0.0001 for PAM). In addition, freshly isolated PAM secreted more cathepsin D than did freshly isolated PBM (5.8 +/- 3.2 micrograms/10(6) cells vs 0.83 +/- 0.83 micrograms/10(6) cells, P less than 0.02). In the presence of LPS (10 micrograms/ml), cell-associated cathepsin D was inhibited in both PBM and PAM. With the addition of gamma-IFN (500 U/ml), both cell-associated and secreted enzyme were increased in freshly isolated and 10-day-cultured PBM and PAM. In parallel studies, fibronectin secretion (by ELISA assay) in both PBM and PAM increased over time in culture. LPS had no effect on PBM or PAM secretion of human fibronectin while gamma-IFN increased PBM and PAM fibronectin levels. Thus, both macrophage cathepsin D activity and fibronectin secretion are increased by gamma-interferon while macrophage cathepsin D activity, but not fibronectin secretion, is decreased by LPS. These studies demonstrate that human macrophage cathepsin D activity is actively modulated by inflammatory mediators and that macrophage mediators of tissue breakdown and repair are not modulated synchronously.
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PMID:Monocyte-derived macrophage and alveolar macrophage fibronectin production and cathepsin D activity. 210 30

Lysosomal proteinases are increased in the tissue lesions of experimental allergic encephalomyelitis and have been implicated in the degradation of myelin proteins. The cellular origins of the increased proteinases are not known but reactive astrocytes found in areas of increased activity are candidate cells. To evaluate the potential of astrocytes as the source of these proteinases, cathepsin B (CB) and cathepsin D (CD) levels were measured in lysates of cultured astrocytes from neonatal rats. Because astrocytes are activated by inflammatory mediators in demyelinating lesions the effect of activation on proteinase levels was examined. Culture supernatants from mononuclear leukocytes stimulated with either concanavalin A or phytohemagglutinin (PHA) induced significant increases in the astrocytic proteinases. Neither PHA alone, interleukin-1, interleukin-2, nor gamma-interferon induced significant increases. Fractions of the supernatant from PHA stimulated mononuclear leukocytes were tested and activity was found in fractions corresponding to a molecular weight of 45-50,000. These studies demonstrate that astrocytes contain significant amounts of CB and CD activity which can be increased by a factor or factors released by activated mononuclear leukocytes.
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PMID:Activation of astrocytic lysosomal proteinases by factors released by mononuclear leukocytes. 271 Feb 77

The activity (free and total) of cathepsin D and acid phosphatase was studied in cells of peritoneal exudate of mice of different ages in the process of interferon production in the presence of sera from newborn and adult animals. Cathepsin D release in newborn mice upon interferon induction is actively stimulated by serum factors of newborn animals altering lysosome permeability selectively for this enzyme alone. Another lysosomal enzyme, acid phosphatase, was more strongly bound to the structures and showed no such features. With an increased age of the donor the amount of stimulating factors in the serum decreases and that of inhibiting factors increases. Inhibition of cathepsin release from lysosomes by the serum factor of adult animals protects the synthesized interferon molecules from degradation and facilitates intensive interferon production in adult mice. A higher susceptibility of children to virus infections and inefficiency of the earliest defence system, interferon, may be due to degradation of newly synthesized interferon molecules by lysosomal cathepsin D.
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PMID:[Role of age-related serum factors in the mechanism of interferon production]. 615 32

The degradation of 32P-labelled E. coli and the activity of three lysosomal enzymes, acid phosphatase, cathepsin D and beta-glucuronidase, in mouse peritoneal macrophages (MPM) were tested after cultivation of the cells for 24 or 48 hours with 10(1) - 10(4.7) U per ml of a homologous beta-interferon preparation (IFN-beta). Low to moderate concentrations of IFN-beta did not influence bacterial degradation in MPM. However, a reduction in bacterial degradation by 20 per cent or more was seen when the MPM were pre-treated with 10(4.7) U per ml for 24 hours or 10(3) U per ml of IFN-beta for 48 hours. Cultivation of the MPM with 10(2) U per ml of IFN-beta suppressed the activities of the lysosomal enzymes, provided that the cells were treated for 48 hours. The beta--glucuronidase activity was significantly reduced also after 24 hours. Increased release of beta-glucuronidase from MPM to the medium during cultivation with 10(2) U per ml of IFN-beta was also observed. Specific anti-IFN-beta globulin abolished the suppression by IFN-beta on the lysosomal enzyme activities. A human IFN-alpha preparation did not influence bacterial degradation or lysosomal enzyme activities in MPM.
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PMID:Effect of a homologous beta-interferon preparation on degradation of Escherichia coli and on lysosomal enzyme activities in mouse peritoneal macrophages. 617 90

Treatment of mouse peritoneal macrophages by gamma (type II, immune) interferon depressed the ingestion of non-opsonized Escherichia coli mediated by the non specific receptor, and also the intracellular degradation of the ingested bacteria. These effects were time and dose-dependent, and sensitive for trypsin and pH 2 treatment. The intracellular concentration of three lysozomal enzymes, beta-glucuronidase, acid phosphatase and cathepsin D, was elevated in gamma interferon-treated macrophages.
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PMID:Effect of gamma interferon preparations on in vitro phagocytosis and degradation of Escherichia coli by mouse peritoneal macrophages. 618 84

Previous studies have indicated that acid-optimal cysteine proteinase(s) in the endosomal-lysosomal compartments, cathepsins, play a critical role in the proteolytic processing of endocytosed proteins to generate the antigenic peptides presented to the immune system on major histocompatibility complex (MHC) class II molecules. The presentation of these peptides and the expression of MHC class II molecules by macrophages and lymphocytes are stimulated by gamma-interferon (gamma-IFN). We found that treatment of human U-937 monocytes with gamma-IFN increased the activities and the content of the two major lysosomal cysteine proteinases, cathepsins B and L. Assays of protease activity, enzyme-linked immunosorbant assays (ELISA) and immunoblotting showed that this cytokine increased the amount of cathepsin B 5-fold and cathepsin L 3-fold in the lysosomal fraction. By contrast, the aspartic proteinase, cathepsin D, in this fraction was not significantly altered by gamma-IFN treatment. An induction of cathepsins B and L was also observed in mouse macrophages, but not in HeLa cells. These results suggest coordinate regulation in monocytes of the expression of cathepsins B and L and MHC class II molecules. Presumably, this induction of cysteine proteases contributes to the enhancement of antigen presentation by gamma-IFN.
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PMID:Gamma-interferon causes a selective induction of the lysosomal proteases, cathepsins B and L, in macrophages. 772 59

We investigated accessory cell function, antigen (Ag) trafficking, and uptake of immune complexes in isolated nasal epithelial cells (NEC) and airway epithelial cells (AEC), as well as in the two respiratory epithelial cell lines A549 and BEAS-2B. The NEC and AEC were capable of supporting Ag-specific as well as phytohemagglutinin-induced and anti-CD3 antibody-induced T-cell proliferation. We colocalized fluorescein isothiocyanate (FITC)-labeled Ags with human leukocyte antigen (HLA)-DR in A549 and BEAS-2B, utilizing laser confocal microscopy. Respiratory epithelial cells stimulated and unstimulated with interferon (IFN)-gamma were pulsed with FITC-labeled Ags for varying periods and evaluated for their ability to internalize Ag. In the unstimulated cells, intracellular punctate staining was evident at 60 min and persisted up to 120 min. In the IFN-gamma-stimulated cells (100 U/ml for 48 h), uptake occurred at 30 min, was maximal at 60 min, and diminished at 120 min. We conducted kinetic studies in the A549 and BEAS-2B cells, utilizing electron microscopy with colloidal gold-conjugated Ags (Au-OVA). At 15 min, Au-OVA was evident in the early compartments resembling the compartment of uncoupling of receptor and ligand. At 30 min, multivesicular bodies were labeled with Au-OVA, and by 60 min Au-OVA was present in the primary and secondary lysosomes. The FITC-labeled Ags colocalized with an early endosomal marker (anti-cathepsin D), a late endosomal marker (M6PR), a lysosomal marker (CD63), and with 3-(2, 4-dinitroanilino)-3'-aminomethyldipropylamine, a marker of acidic vesicles. The BEAS-2B and A549 cells, and NEC and AEC, expressed surface Fcgamma receptor and internalized IgG immune complexes. The NEC and AEC also expressed the costimulatory molecules CD80 and CD86 as determined with flow cytometry, the reverse transcription-polymerase chain reaction for RNA, and immunohistochemistry, and T-cell proliferation could be blocked by treating NEC and AEC with anti-CD80 and anti-CD86 antibodies. Our findings suggest that respiratory epithelial cells may have a role in local Ag presentation.
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PMID:Antigen trafficking and accessory cell function in respiratory epithelial cells. 1046 Jul 54

Psoriasis is a T cell-mediated inflammatory disease characterized by hyperproliferation and by aberrant differentiation. We found cathepsin D and zinc-alpha(2)-glycoprotein, two catalytic enzymes associated with apoptosis and desquamation, to be present in the stratum corneum of the normal epidermis but absent from the psoriatic plaque. Psoriasis is characterized by an altered response to interferon-gamma (IFN-gamma), including the induction of apoptosis in normal but not in psoriatic keratinocytes, often with opposite effects on gene expression of suprabasal proteins. We found that IFN-gamma binding and signaling were attenuated in psoriasis: The IFN-gamma receptor, the signal transducer and activator of transcription STAT-1, and the interferon regulatory factor IRF-1 were strongly up-regulated by IFN-gamma in normal keratinocytes, but not in psoriatic ones. IFN-gamma strongly up-regulated the expression of the catalytic enzymes cathepsin D and zinc-alpha(2)-glycoprotein in normal keratinocytes but down-regulated them in psoriatic ones; the reverse was true of the apoptotic suppressor bcl-2. We believe that the aberrant response to IFN-gamma plays a central role in the pathophysiology of psoriasis, particularly the disruption of apoptosis and desquamation.
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PMID:Response of keratinocytes from normal and psoriatic epidermis to interferon-gamma differs in the expression of zinc-alpha(2)-glycoprotein and cathepsin D. 1069 72

Lymphocyte proliferation and cytokine production were measured in groups of mice vaccinated (but not subsequently challenge infected) with recombinant forms of Schistosoma japonicum cathepsin D aspartic protease, rSjASP1 (expressed in bacteria; enzymatically inactive) and rSjASP2 (expressed in insect cells; enzymatically active). Both forms of the schistosome enzyme induced significant proliferation of splenocytes recovered from vaccinated mice, and expression of interferon (IFN)-gamma, interleukin (IL)-4 and IL-10 mRNA in these cells was detected using reverse transcriptase-polymerase chain reaction. Secretion of IFN-gamma, IL-4 and IL-10 by splenocytes from vaccinated mice was confirmed and quantified using enzyme-linked immunosorbent assay. IFN-gamma was the most abundant cytokine produced, followed by IL-4 and IL-10 in rank order. These findings indicated that vaccination of mice with the schistosome protease induces a mixed Th1/Th2 cytokine response, which may explain the modest level of protection after challenge infection in cathepsin D-vaccinated mice, reported previously.
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PMID:Cellular responses to Schistosoma japonicum cathepsin D aspartic protease. 1216 22

The monocyte-like human histiocytic lymphoma cell line U937 can be induced by phorbol 12-myristate 13-acetate (PMA) to undergo differentiation into a macrophage-like phenotype. We have used two-dimensional gel electrophoresis (2-DE), oligonucleotide microarrays and principal component analysis (PCA) to characterize the U937 cell line as a model system for the differentiation of monocytes into macrophages. A total of 226 differentially expressed proteins were found, of which 41 were selected by PCA for identification using matrix-assisted laser desorption/ionization tandem mass spectrometry. Based on the PCA results, three marker proteins were selected for confirmation of differential expression using Western blot and quantitative real time-PCR. The selected marker proteins were: gamma interferon inducible lysosomal thiol reductase, cathepsin D and adipocyte-fatty acid binding protein. All three proved to be good differentiation markers for macrophage maturation of U937 cells as well as peripheral blood-derived macrophages. The transcriptomics data revealed a large number of additional putative differentiation markers in U937 macrophages, many of which are known to be expressed in peripheral blood-derived macrophages. These include osteospontin, matrix metalloproteinase 9, and HC-gp39. Our results show that the characteristics of U937 macrophages resemble those of inflammatory (exudate) macrophages, exemplified by the down-regulation of 5' nucleotidase and the up-regulation of leucine aminopeptidase mRNAs. In conclusion, using the powerful combination of transcriptomics, 2-DE and PCA, our results show that U937 cells differentiated by PMA treatment are an excellent model system for monocyte derived macrophage generation from blood.
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PMID:A combination of proteomics, principal component analysis and transcriptomics is a powerful tool for the identification of biomarkers for macrophage maturation in the U937 cell line. 1504 83


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