| 1. |
- Demirel, Isak, et al.
(författare)
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Expression of suppressor of cytokine signalling 3 (SOCS3) in human bladder epithelial cells infected with uropathogenic Escherichia coli
- 2013
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 121:2, s. 158-167
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Tidskriftsartikel (refereegranskat)abstract
- Suppressor of cytokine signalling (SOCS) proteins inhibit pro-inflammatory signalling mediated by Janus-activated kinase (JAK)-signal transducer and activator of transcription (STAT) pathways. To evade the immune response some pathogens appear to modify the host SOCS proteins. Uropathogenic Escherichia coli (UPEC) are able to subvert the host response evoked by bladder epithelial cells, but the mechanisms are not fully understood. The objective of this study was to investigate whether UPEC can modify the host SOCS and STAT3 response. Real time RT-PCR studies demonstrated an increased SOCS1 and SOCS3 expression in the isolated human bladder epithelial cell lines (RT-4 and 5637) in response to cytokines. UPEC strain IA2 increased SOCS3, but not SOCS1, mRNA levels with a peak at 6h after infection. The increase of SOCS3 was confirmed at the protein level by Western blotting. The UPEC strain IA2 caused a time-dependent decrease in the phosphorylation of STAT3. This study demonstrates that UPEC are able to affect SOCS3 and STAT3 signalling in human uroepithelial cells. The finding that UPEC are able to induce mediators involved in suppression of host cytokine signalling may help to elucidate how UPEC may circumvent the host response during urinary tract infection.
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| 2. |
- Demirel, Isak, 1987-, et al.
(författare)
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Nitric oxide activates IL-6 production and expression in human renal epithelial cells
- 2012
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Ingår i: American Journal of Nephrology. - Basel, Switzerland : S. Karger. - 0250-8095 .- 1421-9670. ; 36:6, s. 524-530
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: Increased nitric oxide (NO) production or inducible form of NO synthase activity have been documented in patients suffering from urinary tract infection (UTI), but the role of NO in this infection is unclear. We investigated whether NO can affect the host response in human renal epithelial cells by modulating IL-6 production and mRNA expression. Methods: The human renal epithelial cell line A498 was infected with a uropathogenic Escherichia coli (UPEC) strain and/or the NO donor DETA/NO. The IL-6 production and mRNA expression were evaluated by ELISA and real-time RT-PCR. IL-6 mRNA stability was evaluated by analyzing mRNA degradation by real-time RT-PCR.Results: DETA/NO caused a significant (p < 0.05) increase in IL-6 production. Inhibitors of p38 MAPK and ERK1/2 signaling, but not JNK, were shown to significantly suppress DETA/NO-induced IL-6 production. UPEC-induced IL-6 production was further increased (by 73 ± 23%, p < 0.05) in the presence of DETA/NO. The IL-6 mRNA expression increased 2.1 ± 0.17-fold in response to DETA/NO, while the UPEC-evoked increase was pronounced (20 ± 4.5-fold). A synergistic effect of DETA/NO on UPEC-induced IL-6 expression was found (33 ± 7.2-fold increase). The IL-6 mRNA stability studies showed that DETA/NO partially attenuated UPEC-induced degradation of IL-6 mRNA.Conclusions: NO was found to stimulate IL-6 in renal epithelial cells through p38 MAPK and ERK1/2 signaling pathways and also to increase IL-6 mRNA stability in UPEC-infected cells. This study proposes a new role for NO in the host response during UTI by modulating the transcription and production of the cytokine IL-6.
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| 3. |
- Kruse, Robert, 1972-, et al.
(författare)
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Adenosine triphosphate induced P2Y(2) receptor activation induces proinflammatory cytokine release in uroepithelial cells
- 2012
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Ingår i: Journal of Urology. - : Elsevier. - 0022-5347 .- 1527-3792. ; 188:6, s. 2419-2425
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: We characterized and identified the uroepithelial P2 receptor responsible for adenosine triphosphate mediated release of the cytokines interleukin-8 and 6.Materials and Methods: The human renal epithelial cell line A498 (ATCC™) was cultured and stimulated with different purinergic agonists with or without prior inhibition with different antagonists or signaling pathway inhibitors. Supernatant was analyzed for interleukin-8 and 6 by enzyme-linked immunosorbent assay. P2 receptor mRNA expression was assessed by real-time reverse transcriptase-polymerase chain reaction. The candidate receptor was knocked down with siRNA technology. Interleukin-8 and 6 responses were measured after purinergic stimulation of knocked down cells.Results: ATP and ATP-γ-S (Roche Diagnostics, Mannheim, Germany) were equipotent as inducers of interleukin-8 and 6 release. Agonist profile experiments using different P2 receptor agonists indicated that P2Y(2) was the main contributor to this release, although P2Y(11) and P2X(7) activation could not be excluded. Signaling pathway experiments showed that interleukin-8 release involved phospholipase C and inositol trisphosphate mediated signaling, indicating a P2Y receptor subtype. Antagonist experiments indicated P2Y(2) as the responsible receptor. Gene expression analysis of P2 receptors showed that strong expression of P2Y(2) receptor and subsequent knockdown of P2Y(2) receptor mRNA for 72 and 96 hours abrogated interleukin-8 and 6 release after purinergic stimulation with adenosine triphosphate-γ-S.Conclusions: Interleukin-8 and 6 release after purinergic stimulation in uroepithelial A498 cells is mediated through P2Y(2) receptor activation.
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| 4. |
- Kruse, Robert, 1972-, et al.
(författare)
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IL-8 and global gene expression analysis define a key role of ATP in renal epithelial cell responses induced by uropathogenic bacteria
- 2014
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Ingår i: Purinergic Signalling Purinergic Signalling. - Dordrect, Netherlands : Springer. - 1573-9538 .- 1573-9546. ; 10:3, s. 499-508
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Tidskriftsartikel (refereegranskat)abstract
- The recent recognition of receptor-mediated ATP signalling as a pathway of epithelial pro-inflammatory cytokine release challenges the ubiquitous role of the TLR4 pathway during urinary tract infection. The aim of this study was to compare cellular responses of renal epithelial cells infected with uropathogenic Escherichia coli (UPEC) strain IA2 to stimulation with ATP-gamma-S. A498 cells were infected or stimulated in the presence or absence of apyrase, that degrades extracellular ATP, or after siRNA-mediated knockdown of ATP-responding P2Y(2) receptors. Cellular IL-8 release and global gene expression were analysed. Both IA2 and A498 cells per se released ATP, which increased during infection. IA2 and ATP-gamma-S caused a similar to 5-fold increase in cellular release of IL-8 and stimulations performed in the presence of apyrase or after siRNA knockdown of P2Y(2) receptors resulted in attenuation of IA2-mediated IL-8 release. Microarray results show that both IA2 and ATP-gamma-S induced marked changes in gene expression of renal cells. Thirty-six genes were in common between both stimuli, and many of these are key genes belonging to classical response pathways of bacterial infection. Functional analysis shows that 88 biological function-annotated cellular pathways were identical between IA2 and ATP-gamma-S stimuli. Results show that UPEC-induced release of IL-8 is dependent on P2Y(2) signalling and that cellular responses elicited by UPEC and ATP-gamma-S have many identical features. This indicates that renal epithelial responses elicited by bacteria could be mediated by bacteria- or host-derived ATP, thus defining a key role of ATP during infection.
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| 5. |
- Mohlin, Camilla, et al.
(författare)
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Studies of the extracellular ATP-adenosine pathway in human urinary tract epithelial cells
- 2009
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Ingår i: Pharmacology. - : S. Karger AG. - 0031-7012 .- 1423-0313. ; 84:4, s. 196-202
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Tidskriftsartikel (refereegranskat)abstract
- The data demonstrate that adenosine formation from extracellular ATP is negligible in urinary tract epithelial cells due to low CD39 expression in this cell type. However, the epithelial cells express CD73 and are able to convert extracellular AMP to adenosine.
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| 6. |
- Sandholm, Kerstin, et al.
(författare)
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Early Cytokine Release in Response to Live Borrelia burgdorferi Sensu Lato Spirochetes Is Largely Complement Independent
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:9, s. e108013-
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Here we investigated the role of complement activation in phagocytosis and the release of cytokines and chemokines in response to two clinical isolates: Borrelia afzelii K78, which is resistant to complement-mediated lysis, and Borrelia garinii LU59, which is complement-sensitive. Methods: Borrelia spirochetes were incubated in hirudin plasma, or hirudin-anticoagulated whole blood. Complement activation was measured as the generation of C3a and sC5b-9. Binding of the complement components C3, factor H, C4, and C4BP to the bacterial surfaces was analyzed. The importance of complement activation on phagocytosis, and on the release of cytokines and chemokines, was investigated using inhibitors acting at different levels of the complement cascade. Results: 1) Borrelia garinii LU59 induced significantly higher complement activation than did Borrelia afzelii K78. 2) Borrelia afzelii K78 recruited higher amounts of factor H resulting in significantly lower C3 binding. 3) Both Borrelia strains were efficiently phagocytized by granulocytes and monocytes, with substantial inhibition by complement blockade at the levels of C3 and C5. 4) The release of the pro-inflammatory cytokines and chemokines IL-1 beta, IL-6, TNF, CCL20, and CXCL8, together with the anti-inflammatory IL-10, were increased the most (by>10-fold after exposure to Borrelia). 5) Both strains induced a similar release of cytokines and chemokines, which in contrast to the phagocytosis, was almost totally unaffected by complement blockade. Conclusions: Our results show that complement activation plays an important role in the process of phagocytosis but not in the subsequent cytokine release in response to live Borrelia spirochetes.
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| 7. |
- Sandholm, Kerstin, et al.
(författare)
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Early Immune Responses to Borrelia garinii and Borrelia afzeliiin Lyme Borreliosis : Local Complement Activation in Erythema Migrans and in vitro Studies ofComplement Activation, Phagocytosis and Cytokine Profile
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- An optimal eradication of spirochetes in Lyme borreliosis depends on the early immune response, including the potent actions of the complement system. We here assessed possible differences between two Borrelia burgdorferi genospecies in their ability to activate complement, and the consequences of complement activation in terms of phagocytosis and induction of cytokines.Early local complement activation was assessed immunohistochemically in skin biopsies from patients with erythema migrans (EM) caused by B. afzelii or B. garinii. Complement activation, phagocytosis and early cytokine and chemokine release were studied in vitro by incubating clinical isolates of B. afzelii (K78 from a human skin biopsy) and B. garinii (LU59 from human cerebrospinal fluid) in human whole blood.B. afzelii and B. garinii were detected in skin biopsies from EM and deposition of C3-fragments and IgG was found adjacent to the spirochetes. In vitro, B. garinii LU59 induced higher complement activation (measured as the generation of C3a and C5b-9), while B. afzelii K78 recruited more factor H. Phagocytosis by granulocytes and monocytes was demonstrated to be largely dependent on complement activation since phagocytosis was substantially reduced by addition of the C3 inhibitor compstatin or a C5a receptor antagonist. The early cytokine and chemokine release in human blood in response to live spirochetes revealed a rapid and pronounced pro-inflammatory response, mainly associated with the Th1- and Th17-types.We conclude that complement is activated locally in the skin in EM, and that B. garinii LU59 activates complement more than B. afzelii K78. Complement activation is pivotal for efficient phagocytosis of Borrelia spirochetes, especially in early infection before specific antibodies are produced. Both B. garinii LU59 and B. afzelii K78 induce proinflammatory cytokines rapidly, but no clear differences were seen between the two genospecies in this respect.
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| 8. |
- 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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| 9. |
- Svensson, Lovisa, et al.
(författare)
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The effect of nitric oxide on adherence of P-fimbriated uropathogenic Escherichia coli to human renal epithelial cells
- 2010
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Ingår i: BJU International. - Malden, USA : Wiley-Blackwell. - 1464-4096 .- 1464-410X. ; 105:12, s. 1726-1731
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To examine the effect of nitric oxide (NO), an endogenous component of the host defence in urinary tract infection, on the adherence of P-fimbriated uropathogenic Escherichia coli (UPEC) to human renal epithelial cells.Materials and Methods: Two wild-type UPEC strains (AD110 and IA2) and the P-fimbriated recombinant strain HB101pPIL-75 were used. Bacteria were allowed to adhere to the human renal epithelial cell line A498 and attachment was evaluated in the absence or presence of the NO donor DETA/NONOate (1 mm). Total RNA was extracted from NO-exposed bacteria in static urine cultures, followed by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis of the papG gene that encodes the P-fimbriae adhesin PapG.Results: Bacterial adherence to A498 cells was fimbriae-dependent and the ability to agglutinate human P-1 positive erythrocytes confirmed that the used strains were P-fimbriated. UPEC strains AD110 and IA2 attached by a mean of 8 bacteria/cell and 20 bacteria/cell, respectively. In the presence of DETA/NONOate, the attachment of AD110 and IA2 to A498 cells was significantly reduced by a mean (sem) of 34 (3.9)% and 45 (14)%, respectively. The expression of papG was decreased after DETA/NONOate exposure as shown by semiquantitative RT-PCR.Conclusion: NO disrupted functional adhesion of P-fimbriated UPEC to kidney epithelial cells, suggesting that NO-production from epithelial cells in the urinary tract may limit bacterial colonization at the mucosal surface. The reduced adherence may involve transcriptional effects of NO on papG expression, but further studies are needed to establish the underlying mechanisms.
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| 10. |
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