Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.36 (hyaluronidase)
 4,606 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have isolated and characterized the human cardiac mast cell (CMC) and compared this novel mast cell (MC type with MC obtained from uterus, skin, and lung. Heart tissue was obtained from 14 patients with cardiomyopathy (CMP, heart transplantation). CMC were isolated by enzymatic digestion using collagenase, pronase-E, hyaluronidase, and DNAse. Substantial amounts of CMC (0.5% to 1.5% of isolated cells) were found in the atrial appendages but not in ventricular digests or other sites of the heart (< 0.1%). In situ staining of atrial tissue revealed the presence of CMC in the myocardium (2.16 +/- 0.7 MC/mm2), endocardium (2.24 +/- 0.9 MC/mm2), and epicardium. As assessed by combined toluidine blue/immunofluorescence staining with monoclonal antibodies (MoAbs), isolated CMC expressed surface IgE, the receptor for stem cell factor (c-kit receptor/CD117), the p24 antigen (CD9), the Pgp-1 homing receptor (CD44), the pan leukocyte antigen (CD45), and the ICAM-1 antigen (CD54). CMC were not recognized by MoAbs to lymphocyte function associated antigen 2 (LFA-2; CD2), T-cell receptor (TcR; CD3), T4 antigen (CD4), LFA-1 alpha-chain (CD11a), C3biR alpha-chain (CD11b), CR4 alpha-chain (CD11c), LPS-R related Ag (CD14), 3-FAL/x-hapten (CD15), Fc gamma RIII (CD16), lactosylceramid (CDw17), the B-cell antigen CD19, or CR1 (CD35). In situ expression of leukocyte antigens on CMC was demonstrable by indirect immunoperoxidase staining technique and double-labeling immunohistochemistry. Almost all CMC (90%) reacted with MoAbs against tryptase and chymase and thus were MCTC. Cardiac mast cells were also stained by the heparin-binding dye Berberine sulfate and expressed measurable amounts of histamine (4.6 +/- 1.4 pg per cell). Cross linking of either IgE receptor or SCF receptor (c-kit) on CMC resulted in histamine secretion (non-specific release: < 6% of total histamine, alpha IgE induced: 12% to 52%; SCF-induced release: 9% to 18%), whereas neither substance P (a skin MC agonist) nor the basophil agonist FMLP showed an effect on CMC. Together, the CMC is an MCTC primarily located in the appendage of the atrium. This novel type of MC exhibits surface membrane antigen and functional properties similar to those of lung and uterus MC.
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PMID:The human cardiac mast cell: localization, isolation, phenotype, and functional characterization. 752 50

Tissue kallikrein (TK) is secreted by serous cells of tracheobronchial submucosal glands and plays a role in allergic airway responses. To better understand the regulation of TK, we used primary cultures of submucosal gland cells that release TK upon stimulation. Media from cultures stimulated with chymase (10(-7) M) showed increased TK activity (0.50 +/- 0.22 mU/ml mean +/- standard error) in comparison with the control group (0.08 +/- 0.02 mU/ml). The increased TK activity was significantly correlated with increases in the levels of the serous cell marker, secretory leukoprotease inhibitor. Anion exchange chromatography of the conditioned culture media showed that TK activity eluted as a broad peak between 1.6 and 1.8 M NaCl, unlike the reported elution (0.3 to 0.6 M NaCl) of kallikreins from other tissues, suggesting that secreted bronchial TK was bound to a negatively charged molecule. Hyaluronidase digestion increased TK activity in both pre- and post-chymase-stimulated culture media, whereas no such change was seen after samples were digested with heparinase or chondroitinase ABC. Further, after hyaluronidase digestion of media, TK eluted from an anion exchange column between 0.3 and 0.6 M NaCl. Enzymatic detection of TK after nondenaturing gel electrophoresis showed that hyaluronidase digestion also reduced the electrophoretic heterogeneity of TK to a single band, whereas adding back hyaluronic acid (HA) to hyaluronidase-digested samples restored the original heterogeneity. Finally, TK activity bound to HA-Sepharose and could be eluted with HA. These studies show that primary cultures of ovine submucosal gland cells secrete TK in a regulated fashion, and that secreted TK binds to HA. This binding reduces TK enzymatic activity; therefore, factors that affect HA turnover could modify the TK activity in the airway lumen. These events could be important in the regulation of kinin-mediated airway inflammation.
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PMID:Bronchial tissue kallikrein activity is regulated by hyaluronic acid binding. 1057 63

Human lung fibroblasts (HLFs) treated with the viral mimetic polyinosine-polycytidylic acid (poly I:C) form an extracellular matrix (ECM) enriched in hyaluronan (HA) that avidly binds monocytes and lymphocytes. Mast cells are important innate immune cells in both asthma and acute respiratory infections including respiratory syncytial virus (RSV); however, the effect of RSV on HA dependent mast cell adhesion and/or function is unknown. To determine if RSV infection of HLFs leads to the formation of a HA-enriched ECM that binds and enhances mast cell activity primary HLFs were infected with RSV for 48 h prior to leukocyte binding studies using a fluorescently labeled human mast cell line (LUVA). Parallel HLFs were harvested for characterization of HA production by ELISA and size exclusion chromatography. In separate experiments, HLFs were infected as above for 48 h prior to adding LUVA cells to HLF wells. Co-cultures were incubated for 48 h at which point media and cell pellets were collected for analysis. The role of the hyaladherin tumor necrosis factor-stimulated gene 6 (TSG-6) was also assessed using siRNA knockdown. RSV infection of primary HLFs for 48 h enhanced HA-dependent LUVA binding assessed by quantitative fluorescent microscopy. This coincided with increased HLF HA synthase (HAS) 2 and HAS3 expression and decreased hyaluronidase (HYAL) 2 expression leading to increased HA accumulation in the HLF cell layer and the presence of larger HA fragments. Separately, LUVAs co-cultured with RSV-infected HLFs for 48 h displayed enhanced production of the mast cell proteases, chymase, and tryptase. Pre-treatment with the HA inhibitor 4-methylumbelliferone (4-MU) and neutralizing antibodies to CD44 (HA receptor) decreased mast cell protease expression in co-cultured LUVAs implicating a direct role for HA. TSG-6 expression was increased over the 48-h infection. Inhibition of HLF TSG-6 expression by siRNA knockdown led to decreased LUVA binding suggesting an important role for this hyaladherin for LUVA adhesion in the setting of RSV infection. In summary, RSV infection of HLFs contributes to inflammation via HA-dependent mechanisms that enhance mast cell binding as well as mast cell protease expression via direct interactions with the ECM.
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PMID:Respiratory Syncytial Virus Infection of Human Lung Fibroblasts Induces a Hyaluronan-Enriched Extracellular Matrix That Binds Mast Cells and Enhances Expression of Mast Cell Proteases. 3204 99