| 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. |
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| 4. |
- Bang, Charlotte Sahlberg, 1967-, et al.
(författare)
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Global gene expression profiling and antibiotic susceptibility after repeated exposure to the carbon monoxide-releasing molecule-2 (CORM-2) in multidrug-resistant ESBL-producing uropathogenic Escherichia coli
- 2017
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 12:6
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Tidskriftsartikel (refereegranskat)abstract
- Treatment of urinary tract infections is today a challenge due to the increasing prevalence of multidrug-resistant ESBL-producing uropathogenic Escherichia coli (UPEC). There is an urgent need for new treatment strategies for multidrug-resistant UPEC and preferably with targets that have low potential for development of resistance. Carbon monoxide-releasing molecules (CORMs) are novel and potent antibacterial agents. The present study examines the transcriptomic targets of CORM-2 in a multidrug-resistant ESBL-producing UPEC isolate in response to a single exposure to CORM-2 and after repeated exposure to CORM-2. The bacterial viability and minimal inhibitory concentration (MIC) were also examined after repeated exposure to CORM-2. Microarray analysis revealed that a wide range of processes were affected by CORM-2, including a general trend of down-regulation in energy metabolism and biosynthesis pathways and up-regulation of the SOS response and DNA repair. Several genes involved in virulence (ibpB), antibiotic resistance (marAB, mdtABC) and biofilm formation (bhsA, yfgF) were up-regulated, while some genes involved in virulence (kpsC, fepCEG, entABE), antibiotic resistance (evgA) and biofilm formation (artIP) were down-regulated. Repeated exposure to CORM-2 did not alter the gene expression patterns, the growth inhibitory response to CORM-2 or the MIC values for CORM-2, cefotaxime, ciprofloxacin and trimethoprim. This study identifies several enriched gene ontologies, modified pathways and single genes that are targeted by CORM-2 in a multidrug-resistant UPEC isolate. Repeated exposure to CORM-2 did not change the gene expression patterns or fold changes and the susceptibility to CORM-2 remained after repeated exposure.
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| 5. |
- Bang, Charlotte Sahlberg, 1967-, et al.
(författare)
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Multiresistant uropathogenic extended-spectrum β-lactamase (ESBL)-producing Escherichia coli are susceptible to the carbon monoxide releasing molecule-2 (CORM-2).
- 2014
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Ingår i: Microbial Pathogenesis. - London : Elsevier. - 0882-4010 .- 1096-1208. ; 66, s. 29-35
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Tidskriftsartikel (refereegranskat)abstract
- Carbon monoxide (CO) releasing molecules (CO-RMs) have been shown to inhibit growth of commensal Escherichia coli (E. coli). In the present study we examined the effect of CORM-2 on uropathogenic E. coli (UPEC) that produces extended-spectrum β-lactamase (ESBL). Viability experiments showed that CORM-2 inhibited the growth of several different ESBL-producing UPEC isolates and that 500 μM CORM-2 had a bactericidal effect within 4 h. The bactericidal effect of CORM-2 was significantly more pronounced than the effect of the antibiotic nitrofurantoin. CORM-2 demonstrated a low level of cytotoxicity in eukaryotic cells (human bladder epithelial cell line 5637) at the concentrations and time-points where the antibacterial effect was obtained. Real-time RT-PCR studies of different virulence genes showed that the expression of capsule group II kpsMT II and serum resistance traT was reduced and that some genes encoding iron acquisition systems were altered by CORM-2. Our results demonstrate that CORM-2 has a fast bactericidal effect against multiresistant ESBL-producing UPEC isolates, and also identify some putative UPEC virulence factors as targets for CORM-2. CO-RMs may be candidate drugs for further studies in the field of finding new therapeutic approaches for treatment of uropathogenic ESBLproducing E. coli.
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| 6. |
- Bang, Charlotte Sahlberg, 1967-, et al.
(författare)
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The antibacterial effect of nitric oxide against ESBL-producing uropathogenic E-coli is improved by combination with miconazole and polymyxin B nonapeptide
- 2014
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Ingår i: BMC Microbiology. - London : BioMed Central. - 1471-2180. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background: Nitric oxide (NO) is produced as part of the host immune response to bacterial infections, including urinary tract infections. The enzyme flavohemoglobin, coded by the hmp gene, is involved in protecting bacterial cells from the toxic effects of NO and represents a potentially interesting target for development of novel treatment concepts against resistant uropathogenic bacteria. The aim of the present study was to investigate if the in vitro antibacterial effects of NO can be enhanced by pharmacological modulation of the enzyme flavohemoglobin.Results: Four clinical isolates of multidrug-resistant extended-spectrum beta-lactamase (ESBL)-producing uropathogenic E. coli were included in the study. It was shown that the NO-donor substance DETA/NO, but not inactivated DETA/NO, caused an initial growth inhibition with regrowth noted after 8 h of exposure. An hmp-deficient strain showed a prolonged growth inhibition in response to DETA/NO compared to the wild type. The imidazole antibiotic miconazole, that has been shown to inhibit bacterial flavohemoglobin activity, prolonged the DETA/NO-evoked growth inhibition. When miconazole was combined with polymyxin B nonapeptide (PMBN), in order to increase the bacterial wall permeability, DETA/NO caused a prolonged bacteriostatic response that lasted for up to 24 h.Conclusion: An NO-donor in combination with miconazole and PMBN showed enhanced antimicrobial effects and proved effective against multidrug-resistant ESBL-producing uropathogenic E. coli.
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| 7. |
- Bälter, Katarina, et al.
(författare)
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A Web-Based Program About Sustainable Development Goals Focusing on Digital Learning, Digital Health Literacy, and Nutrition for Professional Development in Ethiopia and Rwanda : Development of a Pedagogical Method
- 2022
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Ingår i: JMIR Formative Research. - : JMIR Publications Inc.. - 2561-326X. ; 6:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: East African countries face significant societal challenges related to sustainable development goals but have limited resources to address these problems, including a shortage of nutrition experts and health care workers, limited access to physical and digital infrastructure, and a shortage of advanced educational programs and continuing professional development.Objective: This study aimed to develop a web-based program for sustainable development with a focus on digital learning, digital health literacy, and child nutrition, targeting government officials and decision-makers at nongovernmental organizations (NGOs) in Ethiopia and Rwanda.Methods: A web-based program—OneLearns (Online Education for Leaders in Nutrition and Sustainability)—uses a question-based learning methodology. This is a research-based pedagogical method developed within the open learning initiative at Carnegie Mellon University, United States. Participants were recruited during the fall of 2020 from ministries of health, education, and agriculture and NGOs that have public health, nutrition, and education in their missions. The program was conducted during the spring of 2021.Results: Of the 70 applicants, 25 (36%) were selected and remained active throughout the entire program and filled out a pre- and postassessment questionnaire. After the program, of the 25 applicants, 20 (80%, 95% CI 64%-96%) participants reported that their capacity to drive change related to the sustainable development goals as well as child nutrition in their organizations had increased to large extent or to a very large extent. Furthermore, 17 (68%, 95% CI 50%-86%) and 18 (72%, 95% CI 54%-90%) participants reported that their capacity to drive change related to digital health literacy and digital learning had increased to a large extent and to a very large extent, respectively.Conclusions: Digital learning based on a question-based learning methodology was perceived as a useful method for increasing the capacity to drive change regarding sustainable development among government officials and decision-makers at NGOs in Ethiopia and Rwanda.
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| 8. |
- Bälter, Olle, 1962-, et al.
(författare)
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Effect of Personalized Email-Based Reminders on Participants' Timeliness in an Online Education Program : Randomized Controlled Trial
- 2023
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Ingår i: JMIR Formative Research. - : JMIR Publications Inc.. - 2561-326X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Background: Postsecondary students need to be able to handle self-regulated learning and manage schedules set by instructors. This is particularly the case with online courses, as they often come with a limited number of social reminders and less information directly from the teacher compared to courses with physical presence. This may increase procrastination and reduce timeliness of the students. Reminders may be a tool to improve the timeliness of students' study behavior, but previous research shows that the effect of reminders differs between types of reminders, whether the reminder is personalized or general, and depending on the background of the students. In the worst cases, reminders can even increase procrastination. Objective: The aim of this study was to test if personalized email reminders, as compared to general email reminders, affect the time to completion of scheduled online coursework. The personalized reminders included information on which page in the online material the participants ought to be on at the present point in time and the last page they were on during their last session. The general reminders only contained the first part of this information: where they ought to be at the present point in time. Methods: Weekly email reminders were sent to all participants enrolled in an online program, which included 39 professional learners from three East African countries. All participants in the Online Education for Leaders in Nutrition and Sustainability program, which uses a question-based learning methodology, were randomly assigned to either personalized or general reminders. The structure of the study was AB-BA, so that group A received personalized reminders for the first unit, then general reminders for the rest of the course, while group B started with general reminders and received personalized reminders only in the third (and last) unit in the course. Results: In total, 585 email reminders were distributed, of which 390 were general reminders and 195 were personalized. A Bayesian mixed-effects logistic regression was used to estimate the difference in the probability of being on time with one's studies. The probability of being on time was 14 percentage points (95% credible interval 3%-25%) higher following personalized reminders compared to that following general reminders. For a course with 100 participants, this means 14 more students would be on time. Conclusions: Personalized reminders had a greater positive effect than general reminders for a group of adults working full-time while enrolled in our online educational program. Considering how small the intervention was-adding a few words with the page number the student ought to be on to a reminder-we consider this effect fairly substantial. This intervention could be repeated manually by anyone and in large courses with some basic programming.
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| 9. |
- Demirel, Isak, 1987-, et al.
(författare)
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Ceftibuten-induced filamentation of extended spectrum beta lactamase (ESBL)-producing uropathogenic Escherichia coli alters host cell responses during an in vitro infection
- 2015
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Ingår i: Microbial Pathogenesis. - : Elsevier. - 0882-4010 .- 1096-1208. ; 78, s. 52-62
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Tidskriftsartikel (refereegranskat)abstract
- Inadequate and delayed antibiotic treatment of extended spectrum beta-lactamase (ESBL)-producing isolates have been associated with increased mortality of affected patients. The purpose of this study was to compare the host response of human renal epithelial cells and polymorphonuclear leucocyte (PMN) cells when infected by ESBL-producing uropathogenic Escherichia coli (UPEC) isolates in the presence or absence of ineffective antibiotics.The renal epithelial cell line A498 and PMN cells were stimulated with ESBL-producing UPEC isolates in the presence or absence of three different antibiotics (trimetoprim, ceftibuten and ciprofloxacin). Host cell responses were evaluated as release of cytokines (IL-6, IL-8), reactive oxygen species (ROS), ATP and endotoxins. Bacterial morphology and PMN phagocytosis were evaluated by microscopy.In the presence of ceftibuten, 2 out of 3 examined ESBL-isolates changed their morphology into a filamentous form. The presence of ceftibuten enhanced IL-6, IL-8 and ROS-production from host cells, but only from cells stimulated by the filamentous isolates. The bacterial supernatant and not the filamentous bacteria per se was responsible for the increased release of IL-6, IL-8 and ROS. Increased endotoxin and ATP levels were found in the bacterial supernatants from filamentous isolates. Apyrase decreased IL-6 secretion from A498 cells and polymyxin B abolished the increased ROS-production from PMN cells. PMN were able to inhibit the bacterial growth of some ESBL-isolates in the presence of ceftibuten.In conclusion, antibiotic-induced filamentation of ESBL-producing UPEC isolates and the associated release of ATP and endotoxins can alter the host cell response in the urinary tract.
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| 10. |
- Demirel, Isak, 1987-, et al.
(författare)
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Comparison of host response mechanisms evoked by extended spectrum beta lactamase (ESBL)- and non-ESBL-producing uropathogenic E. coli
- 2013
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Ingår i: BMC Microbiology. - London, United Kingdom : BioMed Central. - 1471-2180. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background: Infections caused by extended spectrum beta-lactamases (ESBL)-producing bacteria have been emerging worldwide and the majority of ESBL-producing E. coli strains are isolated from patients with urinary tracts infections. The purpose of this study was to compare the host-response mechanisms in human polymorphonucleated leukocytes (PMN) and renal epithelial cells when stimulated by ESBL-or non-ESBL-producing uropathogenic E. coli (UPEC) isolates. The host-pathogen interaction of these ESBL-producing strains in the urinary tract is not well studied.Results: The ability of ESBL strains to evoke ROS-production from PMN cells was significantly higher than that of the non-ESBL strains. The growth of ESBL strains was slightly suppressed in the presence of PMN compared to non-ESBL strains after 30 min and 2 h, but the opposite was observed after 5 and 6 h. The number of migrating PMN was significantly higher in response to ESBL strains compared to non-ESBL strains. Stimulation of A498 cells with ESBL strains elicited lower production of IL-6 and IL-8 compared to non-ESBL strains.Conclusion: Significant differences in host-response mechanisms were identified when host cells were stimulated by ESBL-or non-ESBL producing strains. The obtained results on the early interactions of ESBL-producing strains with the host immune system may provide valuable information for management of these infections.
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