<i>Campylobacter jejuni</i> Surface-Bound Protease HtrA, but Not the Secreted Protease nor Protease in Shed Membrane Vesicles, Disrupts Epithelial Cell-to-Cell Junctions
Fundamental functions of the intestinal epithelium include the digestion of food, absorption of nutrients, and its ability to act as the first barrier against intruding microbes. <i>Campylobacter jejuni</i> is a major zoonotic pathogen accounting for a substantial portion of bacterial fo...
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MDPI AG
2024-01-01
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| author | Irshad Sharafutdinov Nicole Tegtmeyer Manfred Rohde Annelie Olofsson Zia ur Rehman Anna Arnqvist Steffen Backert |
| author_facet | Irshad Sharafutdinov Nicole Tegtmeyer Manfred Rohde Annelie Olofsson Zia ur Rehman Anna Arnqvist Steffen Backert |
| author_sort | Irshad Sharafutdinov |
| collection | DOAJ |
| description | Fundamental functions of the intestinal epithelium include the digestion of food, absorption of nutrients, and its ability to act as the first barrier against intruding microbes. <i>Campylobacter jejuni</i> is a major zoonotic pathogen accounting for a substantial portion of bacterial foodborne illnesses. The germ colonizes the intestines of birds and is mainly transmitted to humans through the consumption of contaminated poultry meat. In the human gastrointestinal tract, the bacterium triggers campylobacteriosis that can progress to serious secondary disorders, including reactive arthritis, inflammatory bowel disease and Guillain–Barré syndrome. We recently discovered that <i>C. jejuni</i> serine protease HtrA disrupts intestinal epithelial barrier functions via cleavage of the tight and adherens junction components occludin, claudin-8 and E-cadherin. However, it is unknown whether epithelial damage is mediated by the secreted soluble enzyme, by HtrA contained in shed outer-membrane vesicles (OMVs) or by another mechanism that has yet to be identified. In the present study, we investigated whether soluble recombinant HtrA and/or purified OMVs induce junctional damage to polarized intestinal epithelial cells compared to live <i>C. jejuni</i> bacteria. By using electron and confocal immunofluorescence microscopy, we show that HtrA-expressing <i>C. jejuni</i> bacteria trigger efficient junctional cell damage, but not soluble purified HtrA or HtrA-containing OMVs, not even at high concentrations far exceeding physiological levels. Instead, we found that only bacteria with active protein biosynthesis effectively cleave junctional proteins, which is followed by paracellular transmigration of <i>C. jejuni</i> through the epithelial cell layer. These findings shed new light on the pathogenic activities of HtrA and virulence strategies of <i>C. jejuni</i>. |
| first_indexed | 2024-03-08T04:00:02Z |
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| issn | 2073-4409 |
| language | English |
| last_indexed | 2024-03-08T04:00:02Z |
| publishDate | 2024-01-01 |
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| record_format | Article |
| series | Cells |
| spelling | doaj.art-d51819938d0349e7935bcd9fca4a58712024-02-09T15:09:38ZengMDPI AGCells2073-44092024-01-0113322410.3390/cells13030224<i>Campylobacter jejuni</i> Surface-Bound Protease HtrA, but Not the Secreted Protease nor Protease in Shed Membrane Vesicles, Disrupts Epithelial Cell-to-Cell JunctionsIrshad Sharafutdinov0Nicole Tegtmeyer1Manfred Rohde2Annelie Olofsson3Zia ur Rehman4Anna Arnqvist5Steffen Backert6Department of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058 Erlangen, GermanyDepartment of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058 Erlangen, GermanyCentral Facility for Microscopy, Helmholtz Centre for Infection Research, Inhoffenstraße 7, D-38124 Braunschweig, GermanyDepartment of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, SwedenDepartment of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, SwedenDepartment of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, SwedenDepartment of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058 Erlangen, GermanyFundamental functions of the intestinal epithelium include the digestion of food, absorption of nutrients, and its ability to act as the first barrier against intruding microbes. <i>Campylobacter jejuni</i> is a major zoonotic pathogen accounting for a substantial portion of bacterial foodborne illnesses. The germ colonizes the intestines of birds and is mainly transmitted to humans through the consumption of contaminated poultry meat. In the human gastrointestinal tract, the bacterium triggers campylobacteriosis that can progress to serious secondary disorders, including reactive arthritis, inflammatory bowel disease and Guillain–Barré syndrome. We recently discovered that <i>C. jejuni</i> serine protease HtrA disrupts intestinal epithelial barrier functions via cleavage of the tight and adherens junction components occludin, claudin-8 and E-cadherin. However, it is unknown whether epithelial damage is mediated by the secreted soluble enzyme, by HtrA contained in shed outer-membrane vesicles (OMVs) or by another mechanism that has yet to be identified. In the present study, we investigated whether soluble recombinant HtrA and/or purified OMVs induce junctional damage to polarized intestinal epithelial cells compared to live <i>C. jejuni</i> bacteria. By using electron and confocal immunofluorescence microscopy, we show that HtrA-expressing <i>C. jejuni</i> bacteria trigger efficient junctional cell damage, but not soluble purified HtrA or HtrA-containing OMVs, not even at high concentrations far exceeding physiological levels. Instead, we found that only bacteria with active protein biosynthesis effectively cleave junctional proteins, which is followed by paracellular transmigration of <i>C. jejuni</i> through the epithelial cell layer. These findings shed new light on the pathogenic activities of HtrA and virulence strategies of <i>C. jejuni</i>.https://www.mdpi.com/2073-4409/13/3/224<i>Campylobacter</i>serine protease HtrAtight junctionsoccludinE-cadherin |
| spellingShingle | Irshad Sharafutdinov Nicole Tegtmeyer Manfred Rohde Annelie Olofsson Zia ur Rehman Anna Arnqvist Steffen Backert <i>Campylobacter jejuni</i> Surface-Bound Protease HtrA, but Not the Secreted Protease nor Protease in Shed Membrane Vesicles, Disrupts Epithelial Cell-to-Cell Junctions Cells <i>Campylobacter</i> serine protease HtrA tight junctions occludin E-cadherin |
| title | <i>Campylobacter jejuni</i> Surface-Bound Protease HtrA, but Not the Secreted Protease nor Protease in Shed Membrane Vesicles, Disrupts Epithelial Cell-to-Cell Junctions |
| title_full | <i>Campylobacter jejuni</i> Surface-Bound Protease HtrA, but Not the Secreted Protease nor Protease in Shed Membrane Vesicles, Disrupts Epithelial Cell-to-Cell Junctions |
| title_fullStr | <i>Campylobacter jejuni</i> Surface-Bound Protease HtrA, but Not the Secreted Protease nor Protease in Shed Membrane Vesicles, Disrupts Epithelial Cell-to-Cell Junctions |
| title_full_unstemmed | <i>Campylobacter jejuni</i> Surface-Bound Protease HtrA, but Not the Secreted Protease nor Protease in Shed Membrane Vesicles, Disrupts Epithelial Cell-to-Cell Junctions |
| title_short | <i>Campylobacter jejuni</i> Surface-Bound Protease HtrA, but Not the Secreted Protease nor Protease in Shed Membrane Vesicles, Disrupts Epithelial Cell-to-Cell Junctions |
| title_sort | i campylobacter jejuni i surface bound protease htra but not the secreted protease nor protease in shed membrane vesicles disrupts epithelial cell to cell junctions |
| topic | <i>Campylobacter</i> serine protease HtrA tight junctions occludin E-cadherin |
| url | https://www.mdpi.com/2073-4409/13/3/224 |
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