Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report that the enterocytic cells of the HT-29 glc-/+ cell subpopulation strongly expressed two antimicrobial enzymes: the lysozyme and alpha1-antitrypsin. Moreover, we found that 20 to 30% of these cells expressed positive immunoreactivity using the mAbs directed against the gut porcine PR-39 and cecropin P1 antimicrobial peptides, but did not express immunreactivity against the human antimicrobial polymorphonucleated neutrophil-associated HNP 1-3 defensin and the Xenopus skin magainin. The HT-29 glc-/+ cell subpopulation develops bacteriolytic activity against the enterovirulent diffusely adhering C1845 Escherichia coli characterized by dramatic alterations of the bacterial cell, suggesting lysis, and bacterial death. In contrast, no expression of immunoreactivity against the antimicrobial peptides and no C1845 bacterial alteration were found in the cultured human embryonic undifferentiated INT407 cells and the colon adenocarcinoma T84 crypt cells. The development of the bacterial alteration and the expression of the antimicrobial components were examined as a function of the cell differentiation using the Caco-2 cell line which spontaneously differentiates in culture. We found that the bacterial alteration and the expression of the PR-39 immunoreactivity are differentiation-associated events. Altogether, our results suggest that in the intestine the enterocytes could develop antimicrobial defenses participating in the protection of the gut epithelium against enterovirulent microorganisms.
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PMID:Differentiation-associated antimicrobial functions in human colon adenocarcinoma cell lines. 866 Sep 42

We identified antibacterial components in human T and natural killer (NK) cells by using freshly isolated lymphocytes enriched for T and NK cells as starting material. After growing these lymphocytes for 5 days in the presence of interleukin (IL)-2, we isolated and characterized several antibacterial peptides/proteins from the supernatant-alpha-defensins (HNP 1-3), LL-37, lysozyme, and a fragment of histone H2B-although other active components were also present. We then used reverse transcriptase-polymerase chain reaction to search for expression of the gene coding for LL-37 in several B-cell lines, gammadelta T-cell lines, NK clones, and one monocytic cell line, with positive results, but found no expression in several alphabeta T-cell lines. The alpha-defensins (HNP 1-3) were also found to be expressed in several of these cell lines. To confirm the presence of these antibacterial peptides in lymphocytes, we localized them to NK, gammadelta T cells, B cells, and monocytes/macrophages by using double-staining immunohistochemical analysis of freshly isolated lymphocytes. We also found that primary cultures of lymphocytes transcribe and secrete LL-37 and that these processes are affected by IL-6 and interferon-gamma. In addition, we demonstrated that LL-37 has chemotactic activity for polymorphonuclear leukocytes and CD4 T lymphocytes, whereas others have shown chemotactic activity for human alpha-defensins (HNP 1-2). These findings suggest that microbicidal peptides are effector molecules of lymphocytes and that antibacterial activity previously shown to be derived from T and NK cells may be partly mediated by the antibacterial peptides LL-37 and HNP 1-3.
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PMID:The human antimicrobial and chemotactic peptides LL-37 and alpha-defensins are expressed by specific lymphocyte and monocyte populations. 1104 88

The objective of this study was to determine the expression and production of antimicrobial peptides by healthy and inflamed human synovial membranes. Deposition of the antimicrobial peptides lysozyme, lactoferrin, secretory phospholipase A(2) (sPA(2)), matrilysin (MMP7), human neutrophil alpha-defensins 1-3 (HNP 1-3), human beta-defensin 1 (HBD-1), and human beta-defensin 2 (HBD-2) was determined by immunohistochemistry. Expression of mRNA for the antimicrobial peptides bactericidal permeability-increasing protein (BPI), heparin binding protein (CAP37), human cationic antimicrobial protein (LL37), human alpha-defensin 5 (HD5), human alpha-defensin 6 (HD6), HBD-1, HBD-2, and human beta-defensin 3 (HBD-3) was analysed by reverse transcription polymerase chain reaction (RT-PCR). RT-PCR revealed CAP37 and HBD-1 mRNA in samples of healthy synovial membrane. Additionally, HBD-3 and/or LL37 mRNA was detected in synovial membrane samples from patients with pyogenic arthritis (PA), osteoarthritis (OA) or rheumatoid arthritis (RA). BPI, HD5, HD6, and HBD-2 mRNAs were absent from all samples investigated. Immunohistochemistry identified lysozyme, lactoferrin, sPA(2), and MMP7 in type A synoviocytes of all samples. HBD-1 was only present in type B synoviocytes of some of the samples. Immunoreactive HBD-2 peptide was only visible in some inflamed samples. HNP1-3 was detected in both healthy and inflamed synovial membranes. The data suggest that human synovial membranes produce a broad spectrum of antimicrobial peptides. Under inflammatory conditions, the expression pattern changes, with induction of HBD-3 in PA (LL37 in RA; HBD-3 and LL37 in OA) as well as down-regulation of HBD-1. HBD-3 holds therapeutic potential in PA as it has a broad spectrum of antimicrobial activity and accelerates epithelial healing. However, caution is appropriate since defensins also promote fibrin formation and cell proliferation - key elements in joint infection. Clarification of the role of antimicrobial peptides in OA and RA will require further investigation.
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PMID:Antimicrobial peptides are expressed and produced in healthy and inflamed human synovial membranes. 1237 70