| 1. |
- Demirel, Isak, 1987-, et al.
(författare)
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Activation of NLRP3 by uropathogenic Escherichia coli is associated with IL-1β release and regulation of antimicrobial properties in human neutrophils
- 2020
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- The NLRP3 inflammasome and IL-1β have recently been linked to the severity of uropathogenic Escherichia coli (UPEC)-mediated urinary tract infection (UTI). However, not much is known about the contribution of NLRP3 to the antimicrobial properties of neutrophils and the release of IL-1β during UPEC infection. The purpose of this study was to elucidate the mechanisms behind UPEC-induced IL-1β release from human neutrophils, and to investigate the contribution of the NLRP3 inflammasome in neutrophil-mediated inhibition of UPEC growth. We found that the UPEC strain CFT073 increased the expression of NLRP3 and increased caspase-1 activation and IL-1β release from human neutrophils. The IL-1β release was mediated by the NLRP3 inflammasome and by serine proteases in an NF-κB-and cathepsin B-dependent manner. The UPEC virulence factors α-hemolysin, type-1 fimbriae and p-fimbriae were all shown to contribute to UPEC mediated IL-1β release from neutrophils. Furthermore, inhibition of caspase-1 and NLRP3 activation increased neutrophil ROS-production, phagocytosis and the ability of neutrophils to suppress UPEC growth. In conclusion, this study demonstrates that UPEC can induce NLRP3 and serine protease-dependent release of IL-1β from human neutrophils and that NLRP3 and caspase-1 can regulate the antimicrobial activity of human neutrophils against UPEC.
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| 2. |
- Demirel, Isak, 1987-, et al.
(författare)
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Activation of the NLRP3 Inflammasome Pathway by Uropathogenic Escherichia coli Is Virulence Factor-Dependent and Influences Colonization of Bladder Epithelial Cells
- 2018
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Ingår i: Frontiers in Cellular and Infection Microbiology. - : Frontiers Media S.A.. - 2235-2988. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The NLRP3 inflammasome and IL-1 beta release have recently been suggested to be important for the progression of urinary tract infection (UTI). However, much is still unknown regarding the interaction of UPEC and the NLRP3 inflammasome. The purpose of this study was to elucidate what virulence factors uropathogenic Escherichia coil (UPEC) use to modulate NLRP3 inflammasome activation and subsequent IL-1 beta release and the role of NLRP3 for UPEC colonization of bladder epithelial cells. The bladder epithelial cell line 5637, CRISPR/Cas9 generated NLRP3, caspase-1 and mesotrypsin deficient cell lines and transformed primary bladder epithelial cells (HBLAK) were stimulated with UPEC isolates and the non-pathogenic MG1655 strain. We found that the UPEC strain CFT073, but not MG1655, induced an increased caspase-1 activity and IL-1 beta release from bladder epithelial cells. The increase was shown to be mediated by et-hemolysin activation of the NLRP3 inflammasome in an NE-kappa B-independent manner. The effect of-hemolysin on IL-1 beta release was biphasic, initially suppressive, later inductive. Furthermore, the phase-locked type-1-fimbrial ON variant of CFT073 inhibited caspase-1 activation and IL-1 beta release. In addition, the ability of CFT073 to adhere to and invade NLRP3 deficient cells was significantly reduced compare to wild-type cells. The reduced colonization of NLRP3-deficient cells was type-1 fimbriae dependent. In conclusion, we found that the NLRP3 inflammasome was important for type-1 fimbriae-dependent colonization of bladder epithelial cells and that both type-1 fimbriae and alpha-hemolysin can modulate the activity of the NLRP3 inflammasome.
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| 3. |
- Svensson, Lovisa, et al.
(författare)
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Role of flavohemoglobin in combating nitrosative stress in uropathogenic Escherichia coli : implications for urinary tract infection
- 2010
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Ingår i: Microbial Pathogenesis. - : Elsevier BV. - 0882-4010 .- 1096-1208. ; 49:3, s. 59-66
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Tidskriftsartikel (refereegranskat)abstract
- During the course of urinary tract infection (UTI) nitric oxide (NO) is generated as part of the host response. This study investigates the significance of the NO-detoxifying enzyme flavohemoglobin (Hmp) in protection of uropathogenic Escherichia coli (UPEC) against nitrosative stress. An hmp (J96Deltahmp) knockout mutant of UPEC strain J96 was constructed using single-gene deletion. The viability of J96Deltahmp was significantly reduced (P<0.001) compared to the wild-type strain after exposure to the NO-donor DETA/NO. The NO consumption in J96Deltahmp was significantly (P<0.001) impaired compared to J96wt. Screening UPEC isolates from patients with UTI revealed increased hmp expression in all patients. In a competition-based mouse model of UTI, the hmp mutant strain was significantly (P<0.05) out-competed by the wild-type strain. This study demonstrates, for the first time, that Hmp contributes to the protection of UPEC against NO-mediated toxicity in vitro. In addition, hmp gene expression occurs in UPEC isolates from the infected human urinary tract and UPEC that were hmp-deficient had a reduced ability to colonize the mouse urinary tract. Taken together the results suggest that NO detoxification by Hmp may be a fitness advantage factor in UPEC, and a potentially interesting target for development of novel treatment concepts for UTI.
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| 4. |
- Säve, Susanne, et al.
(författare)
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Adenosine receptor expression in Escherichia coli-infected and cytokine-stimulated human urinary tract epithelial cells
- 2009
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Ingår i: BJU International. - : Wiley-Blackwell Publishing Inc.. - 1464-4096 .- 1464-410X. ; 104:11, s. 1758-1765
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To assess the expression and regulation of adenosine receptors in unstimulated, uropathogenic Escherichia coli (UPEC)-infected and cytokine-stimulated human urinary tract epithelial cells, and to examine the regulation of interleukin (IL)-6 secretion in response to A2A receptor activation.Materials and methods: Human urinary tract epithelial cells (A498, T24 and RT4) were grown in cell culture and stimulated with a mixture of pro-inflammatory cytokines (CM) or UPEC. The expression of adenosine receptors was evaluated using semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), Western blot analysis and immunocytochemistry. IL-6 secretion was measured with an enzyme-linked immunosorbent assay.Results: RT-PCR analysis showed the presence of transcripts for the A1, A2A and A2B receptor subtypes but not for the A3 receptor in A498 kidney epithelial cells. The expression of A2A receptor mRNA increased in A498 epithelial cells exposed to CM and UPEC, while A1 and A2B receptor transcripts decreased or remained unchanged. Up-regulation of A2A receptors was confirmed at the protein level using Western blot analysis and immunocytochemistry. There was also an increase in A2A receptor mRNA in human bladder epithelial cells (T24 and RT4) and in mouse bladder uroepithelium in response to cytokines and UPEC. IL-6 secretion in UPEC-infected A498 cells was decreased by 38% when exposed to the A2A receptor agonist CGS 21680.Conclusion: Our data showed a subtype-selective plasticity among adenosine receptors in urinary tract epithelial cells in response to UPEC-infection and cytokines. There was a consistent up-regulation of A2A receptors in kidney and bladder epithelial cells. Functionally, A2A receptor activation reduced UPEC-induced IL-6 secretion. These findings suggest that adenosine might be a previously unrecognized regulator of the mucosal response in urinary tract infection.
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