Article

Antimicrobial peptides are present in immune and host defense cells of the human respiratory and gastrointestinal tracts.

Department of Anatomy, Chair II, Ludwig Maximilian University, 80336 München, Germany.
Cell and Tissue Research (Impact Factor: 3.68). 07/2006; 324(3):449-56. DOI: 10.1007/s00441-005-0127-7
Source: PubMed

ABSTRACT Previous studies have implicated antimicrobial peptides in the host defense of the mammalian intestinal and respiratory tract. The aim of the present study has been to characterize further the expression of these molecules in non-epithelial cells of the human pulmonary and digestive systems by detailed immunohistochemical analysis of the small and large bowel and of the large airways and lung parenchyma. Additionally, cells obtained from bronchoalveolar lavage were analyzed by fluorescent activated cell sorting and immunostaining of cytospin preparations. hBD-1, hBD-2, and LL-37 were detected in lymphocytes and macrophages in the large airways, lung parenchyma, duodenum, and colon. Lymphocytes positive for the peptides revealed a staining pattern and distribution that largely matched that of CD3-positive and CD8-positive T-cells. Macrophages with positive staining for the antimicrobial peptides also stained positively for CD68 and CD74. In view of the morphology of the LL-37-positive and hBD-2-positive mucosal lymphocytes, they are probably also B-cells. Thus, antimicrobial peptides of the defensin and cathelicidin families are present in a variety of non-epithelial cells of mucosal organs. These findings confirm that antimicrobial peptides have multiple functions in the biology of the mucosa of these organs.

0 Bookmarks
 · 
61 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Human β-defensin-2 (HBD-2) is considered a crucial endogenous antimicrobial peptide, performing this role with both a broad spectrum and high performance. To investigate the regulation of β-defensin-2 gene expression by lentinan (LNT) and the relationship possessed other than a dose or time dependence. We cultured pulmonary glandular epithelial cells line (SPC-A-1) in vitro. Following treatment with LNT at different concentration (0, 12.5, 25, 50, 100 and 200 µg/ml) and time (1st, 2nd, 4th, 8th, 16th, 24th and 48th h). Utilising the reverse transcription polymerase chain reaction (RT-PCR) with primer designed for HBD-2, the total RNA was extracted from SPC-A-1 cells and the RT-PCR was performed with primers for HBD-2. The expression of HBD-2 mRNA treated by varying concentration of LNT was significantly higher than those from blank control groups (P
    Food and Agricultural Immunology 01/2009; 20(3):221-230. · 0.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Haemophilus ducreyi is the causative agent of the genital ulcer disease chancroid, which has been shown to facilitate the transmission of HIV. H. ducreyi is likely exposed to multiple sources of antimicrobial peptides in vivo. APs are small, cationic molecules with both bactericidal and immunomodulatory functions. Because H. ducreyi is able to establish and maintain an infection in an environment rich with antimicrobial peptides, we hypothesized that the bacterium was resistant to the bactericidal effects of these peptides. Using a 96-well AP bactericidal assay, we examined H. ducreyi susceptibility to eight human APs likely to be encountered at the site of infection, including the α-defensins human neutrophil peptide-1, human neutrophil peptide-2, human neutrophil peptide-3, and human defensin 5, the β-defensins human β defensin-2, human beta defensin-3, and human beta defensin-4, and the human cathelicidin, LL-37. H. ducreyi survival was compared to the survival of Escherichia coli ML35, a strain known to be susceptible to several antimicrobial peptides. H. ducreyi was significantly more resistant than E. coli ML35 to the bactericidal effects of all peptides tested. Furthermore, we found that representative class I and class II strains of H. ducreyi were each resistant to APs of each functional category, indicating that resistance to antimicrobial peptides could represent a conserved method of pathogenesis for H. ducreyi as a species. The H. ducreyi genome contains a homolog for the Sap influx transporter. To study the role of the H. ducreyi Sap transporter in AP resistance, we generated an isogenic sapA mutant and used the 96-well AP bactericidal assay to compare the AP susceptibility profiles of wild-type H. ducreyi, the sapA mutant and the sapA trans-complement to α-defensins, β-defensins, and LL-37. We observed a 25% decrease in the survival of the sapA mutant when it was exposed to LL-37. These findings suggest that the H. ducreyi Sap transporter plays a role in H. ducreyi resistance to LL-37, but it is likely that other AP resistance mechanisms co-exist within the bacterium.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Tissue destruction associated with the periodontal disease progression is caused by a cascade of host and microbial factors and proteolytic enzymes. Aberrant laminin-332 (Ln-332), human beta defensin (hBD), and matrix metalloproteinase (MMP) functions have been found in oral inflammatory diseases. The null-allele mouse model appears as the next step in oral disease research. The MMP-8 knock-out mouse model allowed us to clarify the involvement of MMP-8 in vivo in oral and related inflammatory diseases where MMP-8 is suggested to play a key role in tissue destruction. The cleaved Ln-332 γ2-chain species has been implicated in the apical migration of sulcular epithelial cells during the formation of periodontal pockets. We demonstrated that increased Ln-332 fragment levels in gingival crevicular fluid (GCF) are strongly associated with the severity of inflammation in periodontitis. Porphyromonas gingivalis trypsin-like proteinase can cleave an intact Ln-332 γ2-chain into smaller fragments and eventually promote the formation of periodontal pockets. hBDs are components of an innate mucosal defense against pathogenic microbes. Our results suggest that P. gingivalis trypsin-like proteinase can degrade hBD and thus reduce the innate immune response. Elevated levels and the increased activity of MMPs have been detected in several pathological tissue-destructive conditions where MMPs are shown to cleave extracellular matrix (ECM) and basement membrane (BM) molecules and to facilitate tissue destruction. Elevated levels of MMP-8 have been reported in many inflammatory diseases. In periodontitis, MMP-8 levels in gingival crevicular fluid (GCF) and in peri-implant sulcular fluid (PISF) are elevated at sites of active inflammation, and the increased levels of MMP-8 are mainly responsible for collagenase activity, which leads to tissue destruction. MMP-25, expressed by neutrophils, is involved in inflammatory diseases and in ECM turnover. MMP-26 can degrade ECM components and serve as an activator of other MMP enzymes. We further confirmed that increased levels and activation of MMP-8, -25, and -26 in GCF, PISF, and inflamed gingival tissue are associated with the severity of periodontal/peri-implant inflammation. We evaluated the role of MMP-8 in P. gingivalis-induced periodontitis by comparing MMP-8 knock-out (MMP8-/-) and wild-type mice. Surprisingly, MMP-8 significantly attenuated P. gingivalis-induced site-specific alveolar bone loss. We also evaluated systemic changes in serum immunoglobulin and lipoprotein profiles among these mouse groups. P. gingivalis infection increased HDL/VLDL particle size in the MMP-8-/- mice, which is an indicator of lipoprotein responses during systemic inflammation. Serum total LPS and IgG antibody levels were enhanced in both mice groups. P. gingivalis-induced periodontitis, especially in MMP-8-/- mice, is associated with severe alveolar bone loss and with systemic inflammatory and lipoprotein changes that are likely to be involved in early atherosclerosis. Parodontiitti ja peri-implantiitti ovat kroonisia tulehdussairauksia hampaita ja keinojuuria eli implantteja ympäröivissä kiinnityskudoksissa. Bakteerien aineenvaihduntatuotteet, entsyymit ja toksiinit, sekä isännän oma puolustusvaste vieraille antigeeneille johtavat parodontiitin ja peri-implantiitin taudinkuville tyypilliseen kova- ja pehmytkudosten tuhoutumiseen ja lopulta hampaiden ja implanttien löystymiseen ja irtoamiseen. Tutkimuksen tavoitteina oli selvittää tiettyjen entsyymien ja proteiinien esiintyminen, ilmentyminen ja aktiivisuus hampaiden kiinnityskudosten tulehduksen isäntävasteessa, tarkentaa MMP-8-entsyymin todellisia vaikutuksia elävässä elimistössä poistogeeni (knock-out) -hiirimallilla sekä lisäksi syventää tietämystä elimistön oman puolustusvasteen roolista kroonisessa tulehduksessa. Hypoteesina oli edellä mainittujen molekyylien mahdollinen aktiivisuus parodontiittissa ja peri-implantiitissa sekä aktiivisuuden merkitys parodontiitin ja peri-implantiitin diagnostiikassa, isännän omassa puolustuksessa ja taudinkuvalle tyypillisessä kiinnityskudostuhossa. Tutkittujen molekyylien aktiivisuus ja ilmentyminen tulehtuneessa ientasku- ja peri-implanttinesteessä tai ienkudoksessa voimistuu tulehduksen vakavuuden myötä. Näiden molekyylien ja entsyymien kohonneet tasot ja aktiivisuuden nousu kuvastavat parodontaali- ja peri-implantti-infektioiden vakavuutta ja osallistuvat tulehduksen syntyyn ja etenemiseen toimien samalla tulehduksen biomarkkereina. MMP-8 toimii osittain suojaavana molekyylinä P. gingivaliksen aiheuttamassa paikallisessa ja systeemisessä tulehdusvasteessa. Totaalinen MMP-8 puutos johtaa lisääntyneeseen alveoliluukatoon sekä seerumin lipoproteiinien muutokseen ateroskleroottisempaan suuntaan. Parodontiitin hoidossa tulisikin keskittyä patologisesti kohonneiden MMP-8 tasojen alentamiseen lähelle normaalia, fysiologista tasoa sen sijaan että MMP-8 tuotantoa ja toimintaa pyritään kokonaan estämään.