| 1. |
- Heinrich, A, et al.
(författare)
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Moraxella catarrhalis induces CEACAM3-Syk-Card9-dependent activation of human granulocytes
- 2016
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Ingår i: Cellular Microbiology. - : Hindawi Limited. - 1462-5814 .- 1462-5822. ; 18:11, s. 1570-1582
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Tidskriftsartikel (refereegranskat)abstract
- The human restricted pathogen Moraxella catarrhalis is an important causal agent for exacerbations in chronic obstructive lung disease (COPD) in adults. In such patients, increased numbers of granulocytes are present in the airways, which correlate with bacteria-induced exacerbations and severity of the disease. Our study investigated whether the interaction of M. catarrhalis with the human granulocyte-specific carcinoembryonic antigen-related cell adhesion molecule (CEACAM)-3 is linked to NF-κB activation, resulting in chemokine production. Granulocytes from healthy donors and NB4 cells were infected with M. catarrhalis in the presence of different inhibitors, blocking antibodies and siRNA. The supernatants were analysed by ELISA for chemokines. NF-κB activation was determined using a luciferase reporter gene assay and chromatin-immunoprecipitation. We found evidence that the specific engagement of CEACAM3 by Moraxella catarrhalis ubiquitous surface protein A1 (UspA1) results in the activation of pro-inflammatory events, such as degranulation of neutrophils, ROS production and chemokine secretion. The interaction of UspA1 with CEACAM3 induced the activation of the NF-κB pathway via Syk and the Card9 pathway and was dependent on the phosphorylation of the CEACAM3 ITAM -like motif. These findings suggest that the CEACAM3 signalling in neutrophils is able to specifically modulate airway inflammation caused by infection with M. catarrhalis.
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| 2. |
- Javaheri, Anahita, et al.
(författare)
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Helicobacter pylori adhesin HopQ engages in a virulence-enhancing interaction with human CEACAMs
- 2017
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Ingår i: Nature Microbiology. - : NATURE PUBLISHING GROUP. - 2058-5276. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- Helicobacter pylori specifically colonizes the human gastric epithelium and is the major causative agent for ulcer disease and gastric cancer development. Here, we identify members of the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family as receptors of H. pylori and show that HopQ is the surface-exposed adhesin that specifically binds human CEACAM1, CEACAM3, CEACAM5 and CEACAM6. HopQ-CEACAM binding is glycan-independent and targeted to the N-domain. H. pylori binding induces CEACAM1-mediated signalling, and the HopQ-CEACAM1 interaction enables translocation of the virulence factor CagA into host cells and enhances the release of pro-inflammatory mediators such as interleukin-8. Based on the crystal structure of HopQ, we found that a beta-hairpin insertion (HopQ-ID) in HopQ's extracellular 3+4 helix bundle domain is important for CEACAM binding. A peptide derived from this domain competitively inhibits HopQ-mediated activation of the Cag virulence pathway, as genetic or antibody-mediated abrogation of the HopQ function shows. Together, our data suggest the HopQ-CEACAM1 interaction to be a potentially promising novel therapeutic target to combat H. pylori-associated diseases.
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| 3. |
- N'Guessan, PD., et al.
(författare)
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The UspA1 protein of Moraxella catarrhalis induces CEACAM-1-dependent apoptosis in alveolar epithelial cells.
- 2007
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Ingår i: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 195:11, s. 1651-1660
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Tidskriftsartikel (refereegranskat)abstract
- Moraxella catarrhalis is a major cause of exacerbations of chronic obstructive pulmonary disease (COPD) and emphysema. M. catarrhalis–specific UspA1 and the epithelial carcinoembryonic antigen-related cell adhesion molecule (CEACAM1) were required to induce apoptosis. M. catarrhalis–induced apoptosis was significantly enhanced in HeLa cells stably transfected with CEACAM1, compared with HeLa cells not expressing CEACAM1. Infected cells showed increased activity of caspases 3, 6, and 9 but not of caspase 8. Reduced expression of Bcl-2, translocation of Bax into the mitochondria, and cytosolic increase of apoptosis-inducing factor in M. catarrhalis–infected cells implicated the involvement of mitochondrial death pathways. In conclusion, M. catarrhalis induced apoptosis in pulmonary epithelial cells—a process that was triggered by interaction between CEACAM1 and UspA1. Thus, M. catarrhalis–induced apoptosis of pulmonary epithelial cells may contribute to the development of COPD and emphysema.
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