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- Asfaw Idosa, Berhane, PhD, 1977-, et al.
(författare)
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Neisseria meningitidis-Induced Caspase-1 Activation in Human Innate Immune Cells Is LOS-Dependent
- 2019
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Ingår i: Journal of Immunology Research. - : Hindawi Publishing Corporation. - 2314-8861 .- 2314-7156.
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Tidskriftsartikel (refereegranskat)abstract
- Meningococcal disease such as sepsis and meningitidis is hallmarked by an excessive inflammatory response. The causative agent, Neisseria meningitidis, expresses the endotoxin lipooligosaccharide (LOS) that is responsible for activation of immune cells and the release of proinflammatory cytokines. One of the most potent proinflammatory cytokines, interleukin-1 (IL-1), is activated following caspase-1 activity in the intracellular multiprotein complex called inflammasome. Inflammasomes are activated by a number of microbial factors as well as danger molecules by a two-step mechanismpriming and licensing of inflammasome activationbut there are no data available regarding a role for inflammasome activation in meningococcal disease. The aim of this study was to investigate if N. meningitidis activates the inflammasome and, if so, the role of bacterial LOS in this activation. Cells were subjected to N. meningitidis, both wild-type (FAM20) and its LOS-deficient mutant (lpxA), and priming as well as licensing of inflammasome activation was investigated. The wild-type LOS-expressing parental FAM20 serogroup C N. meningitidis (FAM20) strain significantly enhanced the caspase-1 activity in human neutrophils and monocytes, whereas lpxA was unable to induce caspase-1 activity as well as to induce IL-1 release. While the lpxA mutant induced a priming response, measured as increased expression of NLRP3 and IL1B, the LOS-expressing FAM20 further increased this priming. We conclude that although non-LOS components of N. meningitidis contribute to the priming of the inflammasome activity, LOS per se is to be considered as the central component of N. meningitidis virulence, responsible for both priming and licensing of inflammasome activation.
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- 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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- 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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- Fadl, Helena E., 1965-, et al.
(författare)
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Randomized controlled study in pregnancy on treatment of marked hyperglycemia that is short of overt diabetes
- 2015
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley-Blackwell. - 0001-6349 .- 1600-0412. ; 94:11, s. 1181-1187
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: A randomized multicenter study was conducted in the Stockholm-orebro areas in Sweden to evaluate how treatment aiming at normoglycemia affects fetal growth, pregnancy and neonatal outcome in pregnant women with severe hyperglycemia.Material and methods: Pregnant women with hyperglycemia defined as fasting capillary plasma glucose <7.0 mmol/L and a two-hour plasma glucose value 10.0 and <12.2 mmol/L following a 75-g oral glucose tolerance test (OGTT) diagnosed before 34 weeks of gestation were randomized to treatment (n=33) or controls (n=36). Women assigned to the control group were blinded for the OGTT results and received routine care. The therapeutic goal was fasting plasma glucose 4-5 mmol/L, and <6.5 mmol/L after a meal. Primary outcomes were size at birth and number of large-for-gestational age (>90th percentile) neonates. Secondary outcomes were pregnancy complications, neonatal morbidity and glycemic control.Results: The planned number of participating women was not reached. There was a significantly reduced rate of large-for-gestational age neonates, 21 vs. 47%, P<0.05. Group differences in pregnancy complications and neonatal morbidity were not detected because of limited statistical power. In total, 66.7% of the women in the intervention group received insulin. Of all measured plasma glucose values, 64.1% were in the target range, 7.2% in the hypoglycemic range and 28.7% above target values. There were no cases of severe hypoglycemia.Conclusions: Aiming for normalized glycemia in a pregnancy complicated by severe hyperglycemia reduces fetal growth but is associated with an increased rate of mild hypoglycemia.
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- 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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| 8. |
- 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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| 9. |
- 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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| 10. |
- Persson, Alexander, 1978-, et al.
(författare)
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Diverse proinflammatory response in pharyngeal epithelial cells upon interaction with Neisseria meningitidis carriage and invasive isolates
- 2024
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Ingår i: BMC Infectious Diseases. - : BioMed Central (BMC). - 1471-2334. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Invasive meningococcal disease (IMD), including sepsis and meningitis, can develop when Neisseria meningitidis bacteria breach the barrier and gain access to the circulation. While IMD is a rare outcome of bacterial exposure, colonization of the oropharynx is present in approximately 10% of the human population. This asymptomatic carriage can be long or short term, and it is unknown which determining factors regulate bacterial colonization. Despite descriptions of many bacterial virulence factors and recent advances in detailed genetic identification and characterization of bacteria, the factors mediating invasion and disease vs. asymptomatic carriage following bacterial colonization remain unknown. The pharyngeal epithelia play a role in the innate immune defense against pathogens, and the aim of this study was to investigate the proinflammatory response of pharyngeal epithelial cells following meningococcal exposure to describe the potential inflammatory mediation performed during the initial host‒pathogen interaction. Clinically relevant isolates of serogroups B, C, W and Y, derived from patients with meningococcal disease as well as asymptomatic carriers, were included in the study.RESULTS: The most potent cellular response with proinflammatory secretion of TNF, IL-6, CXCL8, CCL2, IL-1β and IL-18 was found in response to invasive serogroup B isolates. This potent response pattern was also mirrored by increased bacterial adhesion to cells as well as induced cell death. It was, however, only with serogroup B isolates where the most potent cellular response was toward the IMD isolates. In contrast, the most potent cellular response using serogroup Y isolates was directed toward the carriage isolates rather than the IMD isolates. In addition, by comparing isolates from outbreaks in Sweden (epidemiologically linked and highly genetically similar), we found the most potent proinflammatory response in cells exposed to carriage isolates rather than the IMD isolates.CONCLUSION: Although certain expected correlations between host‒pathogen interactions and cellular proinflammatory responses were found using IMD serogroup B isolates, our data indicate that carriage isolates invoke stronger proinflammatory activation of the epithelial lining than IMD isolates.
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