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Chen C, Li J, Wang J, Zhang M, Zhang L, Lin Z. Oxybutynin ameliorates LPS-induced inflammatory response in human bladder epithelial cells. J Biochem Mol Toxicol 2024; 38:e23584. [PMID: 38009396 DOI: 10.1002/jbt.23584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 10/10/2023] [Accepted: 11/10/2023] [Indexed: 11/28/2023]
Abstract
Urinary tract infection (UTI) mainly results from bacterial infections in the urinary tract and markedly impacts the normal lives of millions of patients worldwide. The infection and damage to urethral epithelial cells is the first and key step of UTI development and is a critical target for treating clinical UTI. Oxybutynin, an agent for treating urinary incontinence, is recently claimed with protective effects on bladder ultrastructure. Our study will assess the impact of Oxybutynin on inflammation in lipopolysaccharide (LPS)-stimulated bladder epithelial cells. Bladder epithelial T24 cells were treated with 1 μg/mL LPS with or without 10 and 20 μM Oxybutynin for 24 h. Increased levels of oxidative stress (OS) biomarkers, such as reactive oxygen species, 8-hydroxy-2'-deoxyguanosine, malondialdehyde, as well as upregulated inducible nitric oxide synthase and promoted release of nitric oxide, were observed in LPS-managed T24 cells, all of which were signally suppressed by Oxybutynin. Furthermore, severe inflammatory responses, including enhanced release of cytokines, upregulated matrix metallopeptidase-2 (MMP-2) and MMP-9, and raised monocyte chemoattractant protein-1 level, were found in LPS-challenged T24 cells, which were markedly reversed by Oxybutynin. Moreover, the activated toll-1ike receptor 4/nuclear factor-κB pathway observed in LPS-managed T24 cells was repressed by Oxybutynin. Collectively, Oxybutynin mitigated LPS-induced inflammatory response in human bladder epithelial cells.
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Affiliation(s)
- Cheng Chen
- Department of Pharmacy, The First People's Hospital of Yibin, Yibin, China
| | - Jiangtao Li
- Department of Rheumatology and Immunology, The First People's Hospital of Yibin, Yibin, China
| | - Juan Wang
- Department of Pharmaceutical Engineering, School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, China
| | - Mao Zhang
- Department of Pharmacy, The First People's Hospital of Yibin, Yibin, China
| | - Lei Zhang
- Department of Pharmacy, The First People's Hospital of Yibin, Yibin, China
| | - Zhihua Lin
- Department of Pharmaceutical Engineering, School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, China
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2
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Yao R, Mao X, Xu Y, Qiu X, Zhou L, Wang Y, Pang B, Chen M, Cao S, Bao L, Bao Y, Guo S, Hu L, Zhang H, Cui X. Polysaccharides from Vaccaria segetalis seeds reduce urinary tract infections by inhibiting the adhesion and invasion abilities of uropathogenic Escherichia coli. Front Cell Infect Microbiol 2022; 12:1004751. [PMID: 36506014 PMCID: PMC9727262 DOI: 10.3389/fcimb.2022.1004751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 11/01/2022] [Indexed: 11/24/2022] Open
Abstract
The seeds of Vaccaria segetalis (Neck.) are from a traditional medicinal plant Garcke, also called Wang-Bu-Liu-Xing in China. According to the Chinese Pharmacopoeia, the seeds of V. segetalis can be used for treating urinary system diseases. This study was designed to investigate the underlying mechanism of VSP (polysaccharides from Vaccaria segetalis) against urinary tract infections caused by uropathogenic Escherichia coli (UPEC). Here, both in vitro and in vivo infection models were established with the UPEC strain CFT073. Bacterial adhesion and invasion into bladder epithelial cells were analyzed. We found that VSP reduced the adhesion of UPEC to the host by inhibiting the expression of bacterial hair follicle adhesion genes. VSP also reduced the invasion of UPEC by regulating the uroplakins and Toll-like receptors of host epithelial cells. In addition, the swarming motility and flagella-mediated motility genes flhC, flhD and Flic of UPEC were diminished after VSP intervention. Taken together, our findings reveal a possible mechanism by which VSP interferes with the adhesion and invasion of UPEC.
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Affiliation(s)
- Rongmei Yao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China,Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Xin Mao
- Guangzhou Baiyunshan Xingqun Pharmaceutical Co., Ltd, Guangzhou, China
| | - Yingli Xu
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xue Qiu
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Lirun Zhou
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yaxin Wang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Bo Pang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Mengping Chen
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Shan Cao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Lei Bao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yanyan Bao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Shanshan Guo
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Limin Hu
- Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Haijiang Zhang
- Jiangsu Key Laboratory of Regional Resource Exploitation and Medicinal Research, Huaiyin Institute of Technology, Huai’an, China,*Correspondence: Haijiang Zhang, ; Xiaolan Cui,
| | - Xiaolan Cui
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China,*Correspondence: Haijiang Zhang, ; Xiaolan Cui,
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3
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Li H, Wu G, Zhao L, Zhang M. Suppressed inflammation in obese children induced by a high-fiber diet is associated with the attenuation of gut microbial virulence factor genes. Virulence 2021; 12:1754-1770. [PMID: 34233588 PMCID: PMC8274444 DOI: 10.1080/21505594.2021.1948252] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In our previous study, a gut microbiota-targeted dietary intervention with a high-fiber diet improved the immune status of both genetically obese (Prader-Willi Syndrome, PWS) and simple obese (SO) children. However, PWS children had higher inflammation levels than SO children throughout the trial, the gut microbiota of the two cohorts was similar. As some virulence factors (VFs) produced by the gut microbiota play a role in triggering host inflammation, this study compared the characteristics and changes of gut microbial VF genes of the two cohorts before and after the intervention using a fecal metagenomic dataset. We found that in both cohorts, the high-fiber diet reduced the abundance of VF, and particularly pathogen-specific, genes. The composition of VF genes was also modulated, especially for offensive and defensive VF genes. Furthermore, genes belonging to invasion, T3SS (type III secretion system), and adherence classes were suppressed. Co-occurrence network analysis detected VF gene clusters closely related to host inflammation in each cohort. Though these cohort-specific clusters varied in VF gene combinations and cascade reactions affecting inflammation, they mainly contained VFs belonging to iron uptake, T3SS, and invasion classes. The PWS group had a lower abundance of VF genes before the trial, which suggested that other factors could also be responsible for the increased inflammation in this cohort. This study provides insight into the modulation of VF gene structure in the gut microbiota by a high-fiber diet, with respect to reduced inflammation in obese children, and differences in VF genes between these two cohorts.
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Affiliation(s)
- Hui Li
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P. R. China
| | - Guojun Wu
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P. R. China
| | - Liping Zhao
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P. R. China.,Ministry of Education Key Laboratory for Systems Biomedicine, Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China.,Department of Biochemistry and Microbiology and New Jersey Institute for Food, Nutrition and Health, School of Environmental and Biological Sciences, Rutgers University, NJ, USA
| | - Menghui Zhang
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P. R. China
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4
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Zhou M, Yang Y, Wu M, Ma F, Xu Y, Deng B, Zhang J, Zhu G, Lu Y. Role of long polar fimbriae type 1 and 2 in pathogenesis of mammary pathogenic Escherichia coli. J Dairy Sci 2021; 104:8243-8255. [PMID: 33814154 DOI: 10.3168/jds.2021-20122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 02/22/2021] [Indexed: 01/17/2023]
Abstract
Escherichia coli is a leading cause of bovine mastitis worldwide. The bacteria can rapidly grow in milk and elicit a strong lipopolysaccharide (LPS)/toll-like receptor-4 (TLR4)-dependent inflammatory response. Recently, the long polar fimbriae (LPF) were identified as a promising virulence factor candidate widely distributed in mammary pathogenic E. coli (MPEC) strains. Mammary pathogenic E. coli possess 2 lpf loci encoding LPF1 and LPF2, respectively. By deleting the major fimbrial subunit gene, lpfA, we found that both LPF1 and LPF2 contribute to MPEC adhesion, invasion, and biofilm formation in vitro. The lpf1A and lpf2A mutants showed reduced cytotoxicity in our in vitro cell infection model. Furthermore, we observed that LPF2 induced a mild TLR4-independent proinflammatory response. The median lethal dose (LD50) of both ∆lpf2A and ∆lpf1A∆lpf2A mutants to BALB/c mice increased by 0.38 and 0.15 logs, respectively, whereas that of wild-type strain MPJS13 was 8.69 logs. In contrast, LPF1 deficiency significantly enhanced the LPS/TLR4-mediated inflammatory response in mammary epithelial cells, and the LD50 of the mutant decreased to 8.18 logs. In conclusion, our data suggested that LPF are important in MPEC colonization of mammary cells and may provide a benefit to bacterial intracellular survival that induces persistent bovine mastitis.
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Affiliation(s)
- Mingxu Zhou
- Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Nanjing 210014, China
| | - Yang Yang
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China; College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
| | - Miaomiao Wu
- College of Animal Science and Technology, Hunan Co-Innovation Center of Animal Production Safety, Hunan Agricultural University, Changsha 410128, China
| | - Fang Ma
- Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Yue Xu
- Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Bihua Deng
- Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Jinqiu Zhang
- Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Guoqiang Zhu
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China; College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China.
| | - Yu Lu
- Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; School of Pharmacy, Jiangsu University, Zhenjiang 212013, China.
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5
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Jung JH, Hong HJ, Gharderpour A, Cho JY, Baek BS, Hur Y, Kim BC, Kim D, Seong SY, Lim JY, Seo SU. Differential interleukin-1β induction by uropathogenic Escherichia coli correlates with its phylotype and serum C-reactive protein levels in Korean infants. Sci Rep 2019; 9:15654. [PMID: 31666593 PMCID: PMC6821743 DOI: 10.1038/s41598-019-52070-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 10/13/2019] [Indexed: 12/29/2022] Open
Abstract
Urinary tract infection (UTI) is one of the most common bacterial infections in infants less than age 1 year. UTIs frequently recur and result in long-term effects include sepsis and renal scarring. Uropathogenic Escherichia coli (UPEC), the most prevalent organism found in UTIs, can cause host inflammation via various virulence factors including hemolysin and cytotoxic necrotizing factors by inducing inflammatory cytokines such as interleukin (IL)-1β. However, the ability of each UPEC organism to induce IL-1β production may differ by strain. Furthermore, the correlation between differential IL-1β induction and its relevance in pathology has not been well studied. In this study, we isolated UPEC from children under age 24 months and infected bone-marrow derived macrophages with the isolates to investigate secretion of IL-1β. We found that children with higher concentrations of C-reactive protein (CRP) were more likely to harbor phylotype B2 UPEC strains that induced more IL-1β production than phylotype D. We also observed a significant correlation between serum CRP level and in vitro IL-1β induction by phylotype B2 UPEC bacteria. Our results highlight the diversity of UPEC in terms of IL-1β induction capacity in macrophages and suggest a potential pathogenic role in UTIs by inducing inflammation in infants.
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Affiliation(s)
- Jong-Hyeok Jung
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.,Wide River Institute of Immunology, Seoul National University College of Medicine, Hongcheon, Gangwon-do, Republic of Korea
| | - Hyun Jung Hong
- Department of Pediatrics, Gyeongsang National University School of Medicine, Jinju, Gyeongsangnam-do, Republic of Korea
| | - Aziz Gharderpour
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.,Wide River Institute of Immunology, Seoul National University College of Medicine, Hongcheon, Gangwon-do, Republic of Korea
| | - Jae Young Cho
- Department of Pediatrics, Gyeongsang National University School of Medicine, Jinju, Gyeongsangnam-do, Republic of Korea
| | - Bum-Seo Baek
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.,Wide River Institute of Immunology, Seoul National University College of Medicine, Hongcheon, Gangwon-do, Republic of Korea
| | - Yong Hur
- Department of Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Byoung Choul Kim
- Division of Nano-bioengineering, Incheon National University, Incheon, Republic of Korea
| | - Donghyun Kim
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Microbiology and Immunology, Institute of Endemic Diseases, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Seung-Yong Seong
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.,Wide River Institute of Immunology, Seoul National University College of Medicine, Hongcheon, Gangwon-do, Republic of Korea.,Department of Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Microbiology and Immunology, Institute of Endemic Diseases, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jae-Young Lim
- Department of Pediatrics, Gyeongsang National University School of Medicine, Jinju, Gyeongsangnam-do, Republic of Korea. .,Gyeongsang Institute of Health Science, Jinju, Gyeongsangnam-do, Republic of Korea.
| | - Sang-Uk Seo
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea. .,Wide River Institute of Immunology, Seoul National University College of Medicine, Hongcheon, Gangwon-do, Republic of Korea. .,Mucosal Immunology Laboratory, University of Ulsan College of Medicine, Seoul, Republic of Korea.
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6
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Luna-Pineda VM, Moreno-Fierros L, Cázares-Domínguez V, Ilhuicatzi-Alvarado D, Ochoa SA, Cruz-Córdova A, Valencia-Mayoral P, Rodríguez-Leviz A, Xicohtencatl-Cortes J. Curli of Uropathogenic Escherichia coli Enhance Urinary Tract Colonization as a Fitness Factor. Front Microbiol 2019; 10:2063. [PMID: 31551993 PMCID: PMC6733918 DOI: 10.3389/fmicb.2019.02063] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 08/21/2019] [Indexed: 01/24/2023] Open
Abstract
Curli, a type of fimbriae widely distributed in uropathogenic Escherichia coli (UPEC), are involved in adhesion to human bladder cell surfaces and biofilm development. The role of UPEC curli was evaluated in a murine model of urinary tract infection. The aim of this study was to establish the role of curli in C57BL/6 mice transurethrally infected with curli-producing and non-curli-producing UPEC strains. We confirmed that curli enhanced UPEC colonization in the urinary tract, resulting in damage to both the bladder and kidney. Intranasal immunization with recombinant CsgA protein protected against colonization by curli-producing UPEC in the urinary tract. Quantification of cytokines from urinary tract organs showed increases in interleukin-6 and tumor necrosis factor (TNF) release in the kidneys 48 h postinfection with curli-producing UPEC. By contrast, mice infected with non-curli-producing UPEC showed the highest release of interleukin-6, -10, and -17A and TNF. Curli may obscure other fimbriae and LPS, preventing interactions with Toll-like receptors. When intranasal immunization with recombinant FimH and PapG proteins and subsequent infection with this strain were performed, cytokine quantification showed a decrease in the stimulation and release by the uroepithelium. Thus, curli are amyloid-like fimbriae that enhances colonization in the urinary tract and a possible fitness factor.
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Affiliation(s)
- Víctor M Luna-Pineda
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México "Federico Gómez", Mexico City, Mexico
| | - Leticia Moreno-Fierros
- Laboratorio de Inmunidad en Mucosas, Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla, Mexico
| | - Vicenta Cázares-Domínguez
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México "Federico Gómez", Mexico City, Mexico
| | - Damaris Ilhuicatzi-Alvarado
- Laboratorio de Inmunidad en Mucosas, Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla, Mexico
| | - Sara A Ochoa
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México "Federico Gómez", Mexico City, Mexico
| | - Ariadnna Cruz-Córdova
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México "Federico Gómez", Mexico City, Mexico
| | - Pedro Valencia-Mayoral
- Departamento de Patología, Hospital Infantil de México "Federico Gómez", Mexico City, Mexico
| | | | - Juan Xicohtencatl-Cortes
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México "Federico Gómez", Mexico City, Mexico
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7
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Demirel I, Persson A, Brauner A, Särndahl E, Kruse R, Persson K. Activation of the NLRP3 Inflammasome Pathway by Uropathogenic Escherichia coli Is Virulence Factor-Dependent and Influences Colonization of Bladder Epithelial Cells. Front Cell Infect Microbiol 2018; 8:81. [PMID: 29662840 PMCID: PMC5890162 DOI: 10.3389/fcimb.2018.00081] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 02/28/2018] [Indexed: 12/30/2022] Open
Abstract
The NLRP3 inflammasome and IL-1β 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 coli (UPEC) use to modulate NLRP3 inflammasome activation and subsequent IL-1β 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-1β release from bladder epithelial cells. The increase was shown to be mediated by α-hemolysin activation of the NLRP3 inflammasome in an NF-κB-independent manner. The effect of α-hemolysin on IL-1β release was biphasic, initially suppressive, later inductive. Furthermore, the phase-locked type-1-fimbrial ON variant of CFT073 inhibited caspase-1 activation and IL-1β 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 α-hemolysin can modulate the activity of the NLRP3 inflammasome.
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Affiliation(s)
- Isak Demirel
- iRiSC - Inflammatory Response and Infection Susceptibility Centre, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.,School of Medical Sciences, Örebro University, Örebro, Sweden
| | - Alexander Persson
- iRiSC - Inflammatory Response and Infection Susceptibility Centre, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.,School of Medical Sciences, Örebro University, Örebro, Sweden
| | - Annelie Brauner
- Department of Microbiology, Tumor and Cell Biology, Division of Clinical Microbiology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Eva Särndahl
- iRiSC - Inflammatory Response and Infection Susceptibility Centre, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.,School of Medical Sciences, Örebro University, Örebro, Sweden
| | - Robert Kruse
- iRiSC - Inflammatory Response and Infection Susceptibility Centre, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.,School of Medical Sciences, Örebro University, Örebro, Sweden.,Department of Clinical Research Laboratory, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Katarina Persson
- iRiSC - Inflammatory Response and Infection Susceptibility Centre, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.,School of Medical Sciences, Örebro University, Örebro, Sweden
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8
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Susceptibility to Urinary Tract Infection: Benefits and Hazards of the Antibacterial Host Response. Microbiol Spectr 2017; 4. [PMID: 27337480 DOI: 10.1128/microbiolspec.uti-0019-2014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
A paradigm shift is needed to improve and personalize the diagnosis of infectious disease and to select appropriate therapies. For many years, only the most severe and complicated bacterial infections received more detailed diagnostic and therapeutic attention as the efficiency of antibiotic therapy has guaranteed efficient treatment of patients suffering from the most common infections. Indeed, treatability almost became a rationale not to analyze bacterial and host parameters in these larger patient groups. Due to the rapid spread of antibiotic resistance, common infections like respiratory tract- or urinary-tract infections (UTIs) now pose new and significant therapeutic challenges. It is fortunate and timely that infectious disease research can offer such a wealth of new molecular information that is ready to use for the identification of susceptible patients and design of new suitable therapies. Paradoxically, the threat of antibiotic resistance may become a window of opportunity, by encouraging the implementation of new diagnostic and therapeutic approaches. The frequency of antibiotic resistance is rising rapidly in uropathogenic organisms and the molecular and genetic understanding of UTI susceptibility is quite advanced. More bold translation of the new molecular diagnostic and therapeutic tools would not just be possible but of great potential benefit in this patient group. This chapter reviews the molecular basis for susceptibility to UTI, including recent advances in genetics, and discusses the consequences for diagnosis and therapy. By dissecting the increasingly well-defined molecular interactions between bacteria and host and the molecular features of excessive bacterial virulence or host-response malfunction, it is becoming possible to isolate the defensive from the damaging aspects of the host response. Distinguishing "good" from "bad" inflammation has been a long-term quest of biomedical science and in UTI, patients need the "good" aspects of the inflammatory response to resist infection while avoiding the "bad" aspects, causing chronicity and tissue damage.
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9
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Callegan MC, Parkunan SM, Randall CB, Coburn PS, Miller FC, LaGrow AL, Astley RA, Land C, Oh SY, Schneewind O. The role of pili in Bacillus cereus intraocular infection. Exp Eye Res 2017; 159:69-76. [PMID: 28336259 PMCID: PMC5492386 DOI: 10.1016/j.exer.2017.03.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 03/09/2017] [Accepted: 03/16/2017] [Indexed: 12/15/2022]
Abstract
Bacterial endophthalmitis is a potentially blinding intraocular infection. The bacterium Bacillus cereus causes a devastating form of this disease which progresses rapidly, resulting in significant inflammation and loss of vision within a few days. The outer surface of B. cereus incites the intraocular inflammatory response, likely through interactions with innate immune receptors such as TLRs. This study analyzed the role of B. cereus pili, adhesion appendages located on the bacterial surface, in experimental endophthalmitis. To test the hypothesis that the presence of pili contributed to intraocular inflammation and virulence, we analyzed the progress of experimental endophthalmitis in mouse eyes infected with wild type B. cereus (ATCC 14579) or its isogenic pilus-deficient mutant (ΔbcpA-srtD-bcpB or ΔPil). One hundred CFU were injected into the mid-vitreous of one eye of each mouse. Infections were analyzed by quantifying intraocular bacilli and retinal function loss, and by histology from 0 to 12 h postinfection. In vitro growth and hemolytic phenotypes of the infecting strains were also compared. There was no difference in hemolytic activity (1:8 titer), motility, or in vitro growth (p > 0.05, every 2 h, 0-18 h) between wild type B. cereus and the ΔPil mutant. However, infected eyes contained greater numbers of wild type B. cereus than ΔPil during the infection course (p ≤ 0.05, 3-12 h). Eyes infected with wild type B. cereus experienced greater losses in retinal function than eyes infected with the ΔPil mutant, but the differences were not always significant. Eyes infected with ΔPil or wild type B. cereus achieved similar degrees of severe inflammation. The results indicated that the intraocular growth of pilus-deficient B. cereus may have been better controlled, leading to a trend of greater retinal function in eyes infected with the pilus-deficient strain. Although this difference was not enough to significantly alter the severity of the inflammatory response, these results suggest a potential role for pili in protecting B. cereus from clearance during the early stages of endophthalmitis, which is a newly described virulence mechanism for this organism and this infection.
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Affiliation(s)
- Michelle C. Callegan
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA,Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, 950 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA,Dean A. McGee Eye Institute, Oklahoma City Oklahoma USA,Corresponding author: DMEI PA-418, 608 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA. Phone: (405) 271-3674, Fax: (405) 271-8128,
| | - Salai Madhumathi Parkunan
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, 950 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA
| | - C. Blake Randall
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA
| | - Phillip S. Coburn
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA
| | - Frederick C. Miller
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 950 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA
| | - Austin L. LaGrow
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA
| | - Roger A. Astley
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA
| | - Craig Land
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA
| | - So-Young Oh
- Department of Microbiology, University of Chicago, 920 East 58
| | - Olaf Schneewind
- Department of Microbiology, University of Chicago, 920 East 58
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Sundac L, Dando SJ, Sullivan MJ, Derrington P, Gerrard J, Ulett GC. Protein-based profiling of the immune response to uropathogenicEscherichia coliin adult patients immediately following hospital admission for acute cystitis. Pathog Dis 2016; 74:ftw062. [DOI: 10.1093/femspd/ftw062] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2016] [Indexed: 01/19/2023] Open
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Urinary Tract Infection Molecular Mechanisms and Clinical Translation. Pathogens 2016; 5:pathogens5010024. [PMID: 26927188 PMCID: PMC4810145 DOI: 10.3390/pathogens5010024] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 02/05/2016] [Accepted: 02/05/2016] [Indexed: 11/17/2022] Open
Abstract
Rapid developments in infection biology create new and exciting options for individualized diagnostics and therapy. Such new practices are needed to improve patient survival and reduce morbidity. Molecular determinants of host resistance to infection are being characterized, making it possible to identify susceptible individuals and to predict their risk for future morbidity. Immunotherapy is emerging as a new strategy to treat infections worldwide and controlled boosting of the host immune defense represents an important therapeutic alternative to antibiotics. In proof of concept studies, we have demonstrated that this approach is feasible. The long-term goal is not just to remove the pathogens but to also develop technologies that restore resistance to infection in disease-prone patients and devise personalized therapeutic interventions. Here, we discuss some approaches to reaching these goals, in patients with urinary tract infection (UTI). We describe critical host signaling pathways that define symptoms and pathology and the genetic control of innate immune responses that balance protection against tissue damage. For some of these genes, human relevance has been documented in clinical studies, identifying them as potential targets for immune-modulatory therapies, as a complement to antibiotics.
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Štaudová B, Micenková L, Bosák J, Hrazdilová K, Slaninková E, Vrba M, Ševčíková A, Kohoutová D, Woznicová V, Bureš J, Šmajs D. Determinants encoding fimbriae type 1 in fecal Escherichia coli are associated with increased frequency of bacteriocinogeny. BMC Microbiol 2015; 15:201. [PMID: 26445407 PMCID: PMC4594643 DOI: 10.1186/s12866-015-0530-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 09/25/2015] [Indexed: 01/03/2023] Open
Abstract
Background To screen whether E. coli strains encoding type 1 fimbriae, isolated from fecal microflora, produce bacteriocins more often relative to fimA-negative E. coli strains of similar origin. Methods PCR assays were used to detect presence of genes encoding 30 bacteriocin determinants (23 colicin- and 7 microcin-encoding genes) and 18 virulence determinants in 579 E. coli strains of human and animal origin isolated from hospitals and animal facilities in the Czech and Slovak Republic. E. coli strains were also classified into phylogroups (A, B1, B2 and D). Results fimA-negative E. coli strains (defined as those possessing none of the 18 tested virulence determinants) were compared to fimA-positive E. coli strains (possessing fimA as the only detected virulence determinant). Strains with identified bacteriocin genes were more commonly found among fimA-positive E. coli strains (35.6 %) compared to fimA-negative E. coli strains (21.9 %, p < 0.01) and this was true for both colicin and microcin determinants (p = 0.02 and p < 0.01, respectively). In addition, an increased number of strains encoding colicin E1 were found among fimA-positive E. coli strains (p < 0.01). Conclusions fimA-positive E. coli strains produced bacteriocins (colicins and microcins) more often compared to fimA-negative strains of similar origin. Since type 1 fimbriae of E. coli have been shown to mediate adhesion to epithelial host cells and help colonize the intestines, bacteriocin synthesis appears to be an additional feature of colonizing E. coli strains. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0530-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Barbora Štaudová
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, Building A6, 625 00, Brno, Czech Republic.
| | - Lenka Micenková
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, Building A6, 625 00, Brno, Czech Republic.
| | - Juraj Bosák
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, Building A6, 625 00, Brno, Czech Republic.
| | - Kristýna Hrazdilová
- Department of Infectious Diseases and Microbiology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences Brno, Palackého tř. 1/3, 612 42, Brno, Czech Republic. .,CEITEC - Central European Institute of Technology, University of Veterinary and Pharmaceutical Sciences Brno, Palackého tř. 1/3, 612 42, Brno, Czech Republic.
| | - Eva Slaninková
- Department of Infectious Diseases and Microbiology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences Brno, Palackého tř. 1/3, 612 42, Brno, Czech Republic.
| | - Martin Vrba
- Department of Clinical Microbiology, Faculty Hospital Brno, Jihlavská 20, 625 00, Brno, Czech Republic.
| | - Alena Ševčíková
- Department of Clinical Microbiology, Faculty Hospital Brno, Jihlavská 20, 625 00, Brno, Czech Republic.
| | - Darina Kohoutová
- 2nd Department of Internal Medicine - Gastroenterology, Charles University in Praha, Faculty of Medicine at Hradec Kralové, University Teaching Hospital, Sokolská 581, Hradec Kralové, 500 05, Czech Republic.
| | - Vladana Woznicová
- Department of Microbiology, Faculty of Medicine, Masaryk University and St. Anne's University Hospital, Pekařská 53, 656 91, Brno, Czech Republic.
| | - Jan Bureš
- 2nd Department of Internal Medicine - Gastroenterology, Charles University in Praha, Faculty of Medicine at Hradec Kralové, University Teaching Hospital, Sokolská 581, Hradec Kralové, 500 05, Czech Republic.
| | - David Šmajs
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, Building A6, 625 00, Brno, Czech Republic.
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Carey AJ, Sullivan MJ, Duell BL, Crossman DK, Chattopadhyay D, Brooks AJ, Tan CK, Crowley M, Sweet MJ, Schembri MA, Ulett GC. Uropathogenic Escherichia coli Engages CD14-Dependent Signaling to Enable Bladder-Macrophage-Dependent Control of Acute Urinary Tract Infection. J Infect Dis 2015; 213:659-68. [PMID: 26324782 DOI: 10.1093/infdis/jiv424] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 08/11/2015] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND CD14, a coreceptor for several pattern recognition receptors and a widely used monocyte/macrophage marker, plays a key role in host responses to gram-negative bacteria. Despite the central role of CD14 in the inflammatory response to lipopolysaccharide and other microbial products and in the dissemination of bacteria in some infections, the signaling networks controlled by CD14 during urinary tract infection (UTI) are unknown. METHODS We used uropathogenic Escherichia coli (UPEC) infection of wild-type (WT) C57BL/6 and Cd14(-/-) mice and RNA sequencing to define the CD14-dependent transcriptional signature and the role of CD14 in host defense against UTI in the bladder. RESULTS UPEC induced the upregulation of Cd14 and the monocyte/macrophage-related genes Emr1/F4/80 and Csf1r/c-fms, which was associated with lower UPEC burdens in WT mice, compared with Cd14(-/-) mice. Exacerbation of infection in Cd14(-/-) mice was associated with the absence of a 491-gene transcriptional signature in the bladder that encompassed multiple host networks not previously associated with this receptor. CD14-dependent pathways included immune cell trafficking, differential cytokine production in macrophages, and interleukin 17 signaling. Depletion of monocytes/macrophages in the bladder by administration of liposomal clodronate led to higher UPEC burdens. CONCLUSIONS This study identifies new host protective and signaling roles for CD14 in the bladder during UPEC UTI.
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Affiliation(s)
- Alison J Carey
- Menzies Health Institute Queensland, Griffith University, Gold Coast School of Medical Science, Griffith University, Gold Coast
| | - Matthew J Sullivan
- Menzies Health Institute Queensland, Griffith University, Gold Coast School of Medical Science, Griffith University, Gold Coast
| | - Benjamin L Duell
- Menzies Health Institute Queensland, Griffith University, Gold Coast School of Medical Science, Griffith University, Gold Coast
| | - David K Crossman
- Heflin Center for Human Genetics, School of Medicine, University of Alabama at Birmingham
| | - Debasish Chattopadhyay
- Division of Infectious Diseases, School of Medicine, University of Alabama at Birmingham
| | - Andrew J Brooks
- University of Queensland Diamantina Institute, The University of Queensland, Translational Research Institute
| | - Chee K Tan
- Menzies Health Institute Queensland, Griffith University, Gold Coast School of Medical Science, Griffith University, Gold Coast
| | - Michael Crowley
- Heflin Center for Human Genetics, School of Medicine, University of Alabama at Birmingham
| | - Matthew J Sweet
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Australia Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Mark A Schembri
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Australia School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Australia
| | - Glen C Ulett
- Menzies Health Institute Queensland, Griffith University, Gold Coast School of Medical Science, Griffith University, Gold Coast Division of Infectious Diseases, School of Medicine, University of Alabama at Birmingham
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Stærk K, Khandige S, Kolmos HJ, Møller-Jensen J, Andersen TE. Uropathogenic Escherichia coli Express Type 1 Fimbriae Only in Surface Adherent Populations Under Physiological Growth Conditions. J Infect Dis 2015; 213:386-94. [PMID: 26290608 DOI: 10.1093/infdis/jiv422] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 08/10/2015] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Most uropathogenic Escherichia coli (UPEC) strains harbor genes encoding adhesive type 1 fimbria (T1F). T1F is a key factor for successful establishment of urinary tract infection. However, UPEC strains typically do not express T1F in the bladder urine, and little is understood about its induction in vivo. METHODS A flow chamber infection model was used to grow UPEC under conditions simulating distinct infection niches in the bladder. Type 1 fimbriation on isolated UPEC was subsequently determined by yeast cell agglutination and immunofluorescence microscopy, and the results were correlated with the ability to adhere to and invade cultured human bladder cells. RESULTS Although inactive during planktonic growth in urine, T1F expression occurs when UPEC settles on and infects bladder epithelial cells or colonizes catheters. As a result, UPEC in these sessile populations enhances bladder cell adhesion and invasion potential. Only T1F-negative UPEC are subsequently released to the urine, thus limiting T1F expression to surface-associated UPEC alone. CONCLUSIONS Our results demonstrate that T1F expression is strictly regulated under physiological growth conditions with increased expression during surface growth adaptation and infection of uroepithelial cells. This leads to separation of UPEC into low-expression planktonic populations and high-expression sessile populations.
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Affiliation(s)
- Kristian Stærk
- Research Unit of Clinical Microbiology Odense University Hospital, Denmark
| | - Surabhi Khandige
- Department of Biochemistry and Molecular Biology, University of Southern Denmark
| | - Hans Jørn Kolmos
- Research Unit of Clinical Microbiology Odense University Hospital, Denmark
| | - Jakob Møller-Jensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark
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Ozer A, Altuntas CZ, Bicer F, Izgi K, Hultgren SJ, Liu G, Daneshgari F. Impaired cytokine expression, neutrophil infiltration and bacterial clearance in response to urinary tract infection in diabetic mice. Pathog Dis 2015; 73:ftv002. [PMID: 25663347 DOI: 10.1093/femspd/ftv002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Diabetic patients have increased susceptibility to infections, and urinary tract infections (UTI) are the most common type in women with diabetes mellitus. Knowledge of bacterial clearance effectiveness following UTI in diabetics is sparse. In this study, the effects of diabetes on bacterial clearance efficiency and components of the innate immune system in response to UTI in a murine model were investigated. Streptozotocin-induced diabetic and control female C57BL/6J mice were infected with uropathogenic Escherichia coli, and bacterial load, expression of chemokines, and neutrophil infiltration in the bladder over time were investigated. Expression levels of histone deacetylases were also measured to address a potential mechanism underlying the phenotype. Bacterial clearance during UTI was significantly prolonged in diabetic mice relative to controls. Neutrophil infiltration in bladder tissue and urine, and both mRNA and protein expression of chemokines MIP-2, KC, MCP-1 and IL-6 in bladder tissue were diminished at early time points after infection in diabetic mice relative to controls. In addition, mRNA levels of histone deacetylases 1-5 were increased in diabetic mice. This is the first study to show an association of impaired bacterial clearance in diabetic mice with suppression of UTI-induced chemokine expression and neutrophil infiltration in the bladder.
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Affiliation(s)
- Ahmet Ozer
- Urology Institute, University Hospitals Case Medical Center and Department of Urology, Case Western Reserve University School of Medicine, 11100 Euclid Avenue, Cleveland, OH 44106, USA Department of Genetics & Genomic Sciences, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Cengiz Z Altuntas
- Urology Institute, University Hospitals Case Medical Center and Department of Urology, Case Western Reserve University School of Medicine, 11100 Euclid Avenue, Cleveland, OH 44106, USA
| | - Fuat Bicer
- Urology Institute, University Hospitals Case Medical Center and Department of Urology, Case Western Reserve University School of Medicine, 11100 Euclid Avenue, Cleveland, OH 44106, USA Department of Chemistry, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44105, USA
| | - Kenan Izgi
- Urology Institute, University Hospitals Case Medical Center and Department of Urology, Case Western Reserve University School of Medicine, 11100 Euclid Avenue, Cleveland, OH 44106, USA Department of Chemistry, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44105, USA
| | - Scott J Hultgren
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Guiming Liu
- Urology Institute, University Hospitals Case Medical Center and Department of Urology, Case Western Reserve University School of Medicine, 11100 Euclid Avenue, Cleveland, OH 44106, USA
| | - Firouz Daneshgari
- Urology Institute, University Hospitals Case Medical Center and Department of Urology, Case Western Reserve University School of Medicine, 11100 Euclid Avenue, Cleveland, OH 44106, USA
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Abstract
The phase variation (reversible on-off switching) of the type 1 fimbrial adhesin of Escherichia coli involves a DNA inversion catalyzed by FimB (switching in either direction) or FimE (on-to-off switching). Here, we demonstrate that RfaH activates expression of a FimB-LacZ protein fusion while having a modest inhibitory effect on a comparable fimB-lacZ operon construct and on a FimE-LacZ protein fusion, indicating that RfaH selectively controls fimB expression at the posttranscriptional level. Further work demonstrates that loss of RfaH enables small RNA (sRNA) MicA inhibition of fimB expression even in the absence of exogenous inducing stress. This effect is explained by induction of σ(E), and hence MicA, in the absence of RfaH. Additional work confirms that the procaine-dependent induction of micA requires OmpR, as reported previously (A. Coornaert et al., Mol. Microbiol. 76:467-479, 2010, doi:10.1111/j.1365-2958.2010.07115.x), but also demonstrates that RfaH inhibition of fimB transcription is enhanced by procaine independently of OmpR. While the effect of procaine on fimB transcription is shown to be independent of RcsB, it was found to require SlyA, another known regulator of fimB transcription. These results demonstrate a complex role for RfaH as a regulator of fimB expression.
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Bein K, Di Giuseppe M, Mischler SE, Ortiz LA, Leikauf GD. LPS-treated macrophage cytokines repress surfactant protein-B in lung epithelial cells. Am J Respir Cell Mol Biol 2013; 49:306-15. [PMID: 23590297 PMCID: PMC3824031 DOI: 10.1165/rcmb.2012-0283oc] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 03/07/2013] [Indexed: 02/04/2023] Open
Abstract
In the mouse lung, Escherichia coli LPS can decrease surfactant protein-B (SFTPB) mRNA and protein concentrations. LPS also regulates the expression, synthesis, and concentrations of a variety of gene and metabolic products that inhibit SFTPB gene expression. The purpose of the present study was to determine whether LPS acts directly or indirectly on pulmonary epithelial cells to trigger signaling pathways that inhibit SFTPB expression, and whether the transcription factor CCAAT/enhancer binding protein (C/EBP)-β (CEBPB) is a downstream inhibitory effector. To investigate the mechanism of SFTPB repression, the human pulmonary epithelial cell lines NCI-H441 (H441) and NCI-H820 (H820) and the mouse macrophage-like cell line RAW264.7 were treated with LPS. Whereas LPS did not decrease SFTPB transcripts in H441 or H820 cells, the conditioned medium of LPS-treated RAW264.7 cells decreased SFTPB transcripts in H441 and H820 cells, and inhibited SFTPB promoter activity in H441 cells. In the presence of neutralizing anti-tumor necrosis factor (TNF) antibodies, the conditioned medium of LPS-treated RAW264.7 cells did not inhibit SFTPB promoter activity. In H441 cells treated with recombinant TNF protein, SFTPB transcripts decreased, whereas CEBPB transcripts increased and the transient coexpression of CEBPB decreased SFTPB promoter activity. Further, CEBPB short, interfering RNA increased basal SFTPB transcripts and countered the decrease of SFTPB transcripts by TNF. Together, these findings suggest that macrophages participate in the repression of SFTPB expression by LPS, and that macrophage-released cytokines (including TNF) regulate the transcription factor CEBPB, which can function as a downstream transcriptional repressor of SFTPB gene expression in pulmonary epithelial cells.
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Affiliation(s)
- Kiflai Bein
- Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15219-3130, USA.
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Role of Uropathogenic Escherichia coli Virulence Factors in Development of Urinary Tract Infection and Kidney Damage. Int J Nephrol 2012; 2012:681473. [PMID: 22506110 PMCID: PMC3312279 DOI: 10.1155/2012/681473] [Citation(s) in RCA: 199] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 11/02/2011] [Accepted: 12/01/2011] [Indexed: 01/17/2023] Open
Abstract
Uropathogenic Escherichia coli (UPEC) is a causative agent in the vast majority of urinary tract infections (UTIs), including cystitis and pyelonephritis, and infectious complications, which may result in acute renal failure in healthy individuals as well as in renal transplant patients. UPEC expresses a multitude of virulence factors to break the inertia of the mucosal barrier. In response to the breach by UPEC into the normally sterile urinary tract, host inflammatory responses are triggered leading to cytokine production, neutrophil influx, and the exfoliation of infected bladder epithelial cells. Several signaling pathways activated during UPEC infection, including the pathways known to activate the innate immune response, interact with calcium-dependent signaling pathways. Some UPEC isolates, however, might possess strategies to delay or suppress the activation of components of the innate host response in the urinary tract. Studies published in the recent past provide new information regarding how virulence factors of uropathogenic E. coli are involved in activation of the innate host response. Despite numerous host defense mechanisms, UPEC can persist within the urinary tract and may serve as a reservoir for recurrent infections and serious complications. Presentation of the molecular details of these events is essential for development of successful strategies for prevention of human UTIs and urological complications associated with UTIs.
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Norinder BS, Köves B, Yadav M, Brauner A, Svanborg C. Do Escherichia coli strains causing acute cystitis have a distinct virulence repertoire? Microb Pathog 2011; 52:10-6. [PMID: 22023989 DOI: 10.1016/j.micpath.2011.08.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 08/18/2011] [Accepted: 08/23/2011] [Indexed: 11/27/2022]
Abstract
Bacterial virulence factors influence the site and severity of urinary tract infections. While pyelonephritis-associated molecular traits have been defined, virulence factors specific for acute cystitis strains have not been identified. This study examined the virulence factor repertoire of 247 Escherichia coli strains, prospectively isolated from women with community-acquired acute cystitis. Fim sequences were present in 96% of the isolates, which also expressed Type 1 fimbriae. Curli were detected in 75%, 13% of which formed cellulose. Pap sequences were present in 47%, 27% were papG+, 23% were prsG+ and 42% expressed P fimbriae. TcpC was expressed by 33% of the strains, 32% in a subgroup of patients who only had symptoms of cystitis and 42% in patients with signs of upper urinary tract involvement; most frequently by the papG+/prsG+ subgroup. Strains with the full fim, pap and TcpC and curli virulence profile were more common in cystitis patients with than in patients without upper tract involvement (p < 0.05). The varied virulence profile of E. coli strains causing acute cystitis suggests that diverse bacterial strains, expressing Type 1 fimbriae trigger a convergent host response, involving pathways that give rise to the characteristic symptoms of acute cystitis.
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Affiliation(s)
- Birgit Stattin Norinder
- Department of Microbiology, Immunology and Glycobiology, Institute of Laboratory Medicine, Lund University, Sölvegatan 23, SE-22362 Lund, Sweden
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Perros F, Lambrecht BN, Hammad H. TLR4 signalling in pulmonary stromal cells is critical for inflammation and immunity in the airways. Respir Res 2011; 12:125. [PMID: 21943186 PMCID: PMC3189122 DOI: 10.1186/1465-9921-12-125] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Accepted: 09/24/2011] [Indexed: 12/25/2022] Open
Abstract
Inflammation of the airways, which is often associated with life-threatening infection by Gram-negative bacteria or presence of endotoxin in the bioaerosol, is still a major cause of severe airway diseases. Moreover, inhaled endotoxin may play an important role in the development and progression of airway inflammation in asthma. Pathologic changes induced by endotoxin inhalation include bronchospasm, airflow obstruction, recruitment of inflammatory cells, injury of the alveolar epithelium, and disruption of pulmonary capillary integrity leading to protein rich fluid leak in the alveolar space. Mammalian Toll-like receptors (TLRs) are important signalling receptors in innate host defense. Among these receptors, TLR4 plays a critical role in the response to endotoxin. Lungs are a complex compartmentalized organ with separate barriers, namely the alveolar-capillary barrier, the microvascular endothelium, and the alveolar epithelium. An emerging theme in the field of lung immunology is that structural cells (SCs) of the airways such as epithelial cells (ECs), endothelial cells, fibroblasts and other stromal cells produce activating cytokines that determine the quantity and quality of the lung immune response. This review focuses on the role of TLR4 in the innate and adaptive immune functions of the pulmonary SCs.
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Affiliation(s)
- Frederic Perros
- Laboratory of Immunoregulation and Department of Respiratory Medicine, University Hospital of Ghent, 185 De Pintelaan, Ghent, B-9000, Belgium.
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Thorley AJ, Grandolfo D, Lim E, Goldstraw P, Young A, Tetley TD. Innate immune responses to bacterial ligands in the peripheral human lung--role of alveolar epithelial TLR expression and signalling. PLoS One 2011; 6:e21827. [PMID: 21789185 PMCID: PMC3137597 DOI: 10.1371/journal.pone.0021827] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 06/07/2011] [Indexed: 01/30/2023] Open
Abstract
It is widely believed that the alveolar epithelium is unresponsive to LPS, in the absence of serum, due to low expression of TLR4 and CD14. Furthermore, the responsiveness of the epithelium to TLR-2 ligands is also poorly understood. We hypothesised that human alveolar type I (ATI) and type II (ATII) epithelial cells were responsive to TLR2 and TLR4 ligands (MALP-2 and LPS respectively), expressed the necessary TLRs and co-receptors (CD14 and MD2) and released distinct profiles of cytokines via differential activation of MAP kinases. Primary ATII cells and alveolar macrophages and an immortalised ATI cell line (TT1) elicited CD14 and MD2-dependent responses to LPS which did not require the addition of exogenous soluble CD14. TT1 and primary ATII cells expressed CD14 whereas A549 cells did not, as confirmed by flow cytometry. Following LPS and MALP-2 exposure, macrophages and ATII cells released significant amounts of TNFα, IL-8 and MCP-1 whereas TT1 cells only released IL-8 and MCP-1. P38, ERK and JNK were involved in MALP-2 and LPS-induced cytokine release from all three cell types. However, ERK and JNK were significantly more important than p38 in cytokine release from macrophages whereas all three were similarly involved in LPS-induced mediator release from TT1 cells. In ATII cells, JNK was significantly more important than p38 and ERK in LPS-induced MCP-1 release. MALP-2 and LPS exposure stimulated TLR4 protein expression in all three cell types; significantly more so in ATII cells than macrophages and TT1 cells. In conclusion, this is the first study describing the expression of CD14 on, and TLR2 and 4 signalling in, primary human ATII cells and ATI cells; suggesting that differential activation of MAP kinases, cytokine secretion and TLR4 expression by the alveolar epithelium and macrophages is important in orchestrating a co-ordinated response to inhaled pathogens.
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Affiliation(s)
- Andrew J. Thorley
- Lung Cell Biology, Section of Pharmacology and Toxicology, National Heart and Lung Institute, Imperial College, London, United Kingdom
| | - Davide Grandolfo
- Lung Cell Biology, Section of Pharmacology and Toxicology, National Heart and Lung Institute, Imperial College, London, United Kingdom
| | - Eric Lim
- Department of Thoracic Surgery, Royal Brompton and Harefield NHS Trust, London, United Kingdom
| | - Peter Goldstraw
- Department of Thoracic Surgery, Royal Brompton and Harefield NHS Trust, London, United Kingdom
| | - Alan Young
- AstraZeneca R&D, Loughborough, United Kingdom
| | - Teresa D. Tetley
- Lung Cell Biology, Section of Pharmacology and Toxicology, National Heart and Lung Institute, Imperial College, London, United Kingdom
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Ragnarsdóttir B, Lutay N, Grönberg-Hernandez J, Köves B, Svanborg C. Genetics of innate immunity and UTI susceptibility. Nat Rev Urol 2011; 8:449-68. [PMID: 21750501 DOI: 10.1038/nrurol.2011.100] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A functional and well-balanced immune response is required to resist most infections. Slight dysfunctions in innate immunity can turn the 'friendly' host defense into an unpleasant foe and give rise to disease. Beneficial and destructive forces of innate immunity have been discovered in the urinary tract and mechanisms by which they influence the severity of urinary tract infections (UTIs) have been elucidated. By modifying specific aspects of the innate immune response to UTI, genetic variation either exaggerates the severity of acute pyelonephritis to include urosepsis and renal scarring or protects against symptomatic disease by suppressing innate immune signaling, as in asymptomatic bacteriuria (ABU). Different genes are polymorphic in patients prone to acute pyelonephritis or ABU, respectively, and yet discussions of UTI susceptibility in clinical practice still focus mainly on social and behavioral factors or dysfunctional voiding. Is it not time for UTIs to enter the era of molecular medicine? Defining why certain individuals are protected from UTI while others have severe, recurrent infections has long been difficult, but progress is now being made, encouraging new approaches to risk assessment and therapy in this large and important patient group, as well as revealing promising facets of 'good' versus 'bad' inflammation.
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Affiliation(s)
- Bryndís Ragnarsdóttir
- Section of Microbiology, Immunology and Glycobiology, Institute of Laboratory Medicine, Lund University, Sölvegatan 23, 22362 Lund, Sweden
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Abstract
Gout is an inflammatory arthritis characterized by abrupt self-limiting attacks of inflammation caused by precipitation of monosodium urate crystals (MSU) in the joint. Recent studies suggest that orchestration of the MSU-induced inflammatory response is dependent on the proinflammatory cytokine IL-1β, underlined by promising results in early IL-1 inhibitor trials in gout patients. This IL-1-dependent innate inflammatory phenotype, which is observed in a number of diseases in addition to gout, is now understood to rely on the formation of the macromolecular NLRP3 inflammasome complex in response to the MSU 'danger signal'. This review focuses on our current understanding of the NLRP3 inflammasome and its critical role in MSU-crystal induced inflammatory gout attacks. It also discusses the management of treatment-resistant acute and chronic tophaceous gout with IL-1 inhibitors; early clinical studies of rilonacept (IL-1 Trap), canakinumab (monoclonal anti-IL-1β antibody), and anakinra have all demonstrated treatment efficacy in such patients.
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Affiliation(s)
- Sarah R Kingsbury
- Section of Musculoskeletal Disease, Leeds Institute of Molecular Medicine, University of Leeds, Leeds, UK
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Hunstad DA, Justice SS. Intracellular lifestyles and immune evasion strategies of uropathogenic Escherichia coli. Annu Rev Microbiol 2010; 64:203-21. [PMID: 20825346 DOI: 10.1146/annurev.micro.112408.134258] [Citation(s) in RCA: 144] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Paradigms in the pathogenesis of urinary tract infections have shifted dramatically as a result of recent scientific revelations. Beyond extracellular colonization of the bladder luminal surface, as traditional clinical thinking would hold, uropathogenic bacteria direct a complex, intracellular cascade that shelters bacteria from host defenses and leads to persistent bacterial residence within the epithelium. After epithelial invasion, many organisms are promptly expelled by bladder epithelial cells; a minority establish a niche in the cytoplasm that results in the development of biofilm-like intracellular bacterial communities and serves as the primary location for bacterial expansion. Exfoliation of the superficial epithelial layer acts to reduce the bacterial load but facilitates chronic residence of small nests of bacteria that later reemerge to cause some episodes of recurrent cystitis, a familiar clinical scenario in otherwise healthy women. Advances in both in vitro and animal models of cystitis promise to provide insights into the bacterial and host transcriptional and biochemical pathways that define these pathogenic stages.
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Affiliation(s)
- David A Hunstad
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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Uropathogenic Escherichia coli modulates immune responses and its curli fimbriae interact with the antimicrobial peptide LL-37. PLoS Pathog 2010; 6:e1001010. [PMID: 20661475 PMCID: PMC2908543 DOI: 10.1371/journal.ppat.1001010] [Citation(s) in RCA: 163] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 06/17/2010] [Indexed: 01/22/2023] Open
Abstract
Bacterial growth in multicellular communities, or biofilms, offers many potential advantages over single-cell growth, including resistance to antimicrobial factors. Here we describe the interaction between the biofilm-promoting components curli fimbriae and cellulose of uropathogenic E. coli and the endogenous antimicrobial defense in the urinary tract. We also demonstrate the impact of this interplay on the pathogenesis of urinary tract infections. Our results suggest that curli and cellulose exhibit differential and complementary functions. Both of these biofilm components were expressed by a high proportion of clinical E. coli isolates. Curli promoted adherence to epithelial cells and resistance against the human antimicrobial peptide LL-37, but also increased the induction of the proinflammatory cytokine IL-8. Cellulose production, on the other hand, reduced immune induction and hence delayed bacterial elimination from the kidneys. Interestingly, LL-37 inhibited curli formation by preventing the polymerization of the major curli subunit, CsgA. Thus, even relatively low concentrations of LL-37 inhibited curli-mediated biofilm formation in vitro. Taken together, our data demonstrate that biofilm components are involved in the pathogenesis of urinary tract infections by E. coli and can be a target of local immune defense mechanisms. Most infections of the urinary tract are caused by uropathogenic E. coli. On abiotic surfaces, these bacteria are able to form biofilms, which protect them from various adverse environmental conditions. In this study, we sought to investigate whether two E. coli biofilm components, curli fimbriae and cellulose, provide a similar protection against innate immune defense mechanisms of the urinary tract. We put special emphasis on the interaction with the human antimicrobial peptide LL-37, which plays a crucial role in the protection against uropathogenic E. coli. We demonstrate that curli expression specifically reduces bacterial sensitivity to LL-37 by binding the peptide before reaching the bacterial cell membrane and exhibiting its bactericidal activity. A more general protection is mediated by cellulose, possibly by hiding immunogenic surface structures of the bacterium. In addition to providing protection, curli are also targeted by the immune system. The formation of new curli fibers is inhibited in the presence of LL-37. Moreover, curliated bacteria show higher immunogenicity than their non-curliated counterparts. Cellulose expression, on the other hand, appears to impair initial host colonization. In conclusion, our findings demonstrate an example of the tight interplay between bacterial virulence factors and the host immune defense.
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Abstract
The urinary tract is a common site of bacterial infections; nearly half of all women experience at least one urinary tract infection (UTI) during their lifetime. These infections are classified based on the condition of the host. Uncomplicated infections affect otherwise healthy individuals and are most commonly caused by uropathogenic Escherichia coli, whereas complicated infections affect patients with underlying difficulties, such as a urinary tract abnormality or catheterization, and are commonly caused by species such as Proteus mirabilis. Virulence and fitness factors produced by both pathogens include fimbriae, toxins, flagella, iron acquisition systems, and proteins that function in immune evasion. Additional factors that contribute to infection include the formation of intracellular bacterial communities by E. coli and the production of urease by P. mirabilis, which can result in urinary stone formation. Innate immune responses are induced or mediated by pattern recognition receptors, antimicrobial peptides, and neutrophils. The adaptive immune response to UTI is less well understood. Host factors TLR4 and CXCR1 are implicated in disease outcome and susceptibility, respectively. Low levels of TLR4 are associated with asymptomatic bacteriuria while low levels of CXCR1 are associated with increased incidence of acute pyelonephritis. Current research is focused on the identification of additional virulence factors and therapeutic or prophylactic targets that might be used in the generation of vaccines against both uropathogens.
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Rudick CN, Billips BK, Pavlov VI, Yaggie RE, Schaeffer AJ, Klumpp DJ. Host-pathogen interactions mediating pain of urinary tract infection. J Infect Dis 2010; 201:1240-9. [PMID: 20225955 DOI: 10.1086/651275] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Pelvic pain is a major component of the morbidity associated with urinary tract infection (UTI), yet the molecular mechanisms underlying UTI-induced pain remain unknown. UTI pain mechanisms probably contrast with the clinical condition of asymptomatic bacteriuria (ASB), characterized by significant bacterial loads without lack symptoms. METHODS A murine UTI model was used to compare pelvic pain behavior elicited by infection with uropathogenic Escherichia coli strain NU14 and ASB strain 83972. RESULTS NU14-infected mice exhibited pelvic pain, whereas mice infected with 83972 did not exhibit pain, similar to patients infected with 83972. NU14-induced pain was not dependent on mast cells, not correlated with bacterial colonization or urinary neutrophils. UTI pain was not influenced by expression of type 1 pili, the bacterial adhesive appendages that induce urothelial apoptosis. However, purified NU14 lipopolysaccharide (LPS) induced Toll-like receptor 4 (TLR4)-dependent pain, whereas 83972 LPS induced no pain. Indeed, 83972 LPS attenuated the pain of NU14 infection, suggesting therapeutic potential. CONCLUSIONS These data suggest a novel mechanism of infection-associated pain that is dependent on TLR4 yet independent of inflammation. Clinically, these findings also provide the rational for probiotic therapies that would minimize the symptoms of infection without reliance on empirical therapies that contribute to antimicrobial resistance.
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Affiliation(s)
- Charles N Rudick
- Department of Urology, Feinberg School of Medicine Northwestern University, Chicago, Illinois, USA
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Sivick KE, Mobley HLT. Waging war against uropathogenic Escherichia coli: winning back the urinary tract. Infect Immun 2010; 78:568-85. [PMID: 19917708 PMCID: PMC2812207 DOI: 10.1128/iai.01000-09] [Citation(s) in RCA: 157] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Urinary tract infection (UTI) caused by uropathogenic Escherichia coli (UPEC) is a substantial economic and societal burden-a formidable public health issue. Symptomatic UTI causes significant discomfort in infected patients, results in lost productivity, predisposes individuals to more serious infections, and usually necessitates antibiotic therapy. There is no licensed vaccine available for prevention of UTI in humans in the United States, likely due to the challenge of targeting a relatively heterogeneous group of pathogenic strains in a unique physiological niche. Despite significant advances in the understanding of UPEC biology, mechanistic details regarding the host response to UTI and full comprehension of genetic loci that influence susceptibility require additional work. Currently, there is an appreciation for the role of classic innate immune responses-from pattern receptor recognition to recruitment of phagocytic cells-that occur during UPEC-mediated UTI. There is, however, a clear disconnect regarding how factors involved in the innate immune response to UPEC stimulate acquired immunity that facilitates enhanced clearance upon reinfection. Unraveling the molecular details of this process is vital in the development of a successful vaccine for prevention of human UTI. Here, we survey the current understanding of host responses to UPEC-mediated UTI with an eye on molecular and cellular factors whose activity may be harnessed by a vaccine that stimulates lasting and sterilizing immunity.
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Affiliation(s)
- Kelsey E. Sivick
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Harry L. T. Mobley
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109
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Polysaccharide capsule and sialic acid-mediated regulation promote biofilm-like intracellular bacterial communities during cystitis. Infect Immun 2010; 78:963-75. [PMID: 20086090 DOI: 10.1128/iai.00925-09] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs). A murine UTI model has revealed an infection cascade whereby UPEC undergoes cycles of invasion of the bladder epithelium, intracellular proliferation in polysaccharide-containing biofilm-like masses called intracellular bacterial communities (IBC), and then dispersal into the bladder lumen to initiate further rounds of epithelial colonization and invasion. We predicted that the UPEC K1 polysaccharide capsule is a key constituent of the IBC matrix. Compared to prototypic E. coli K1 strain UTI89, a capsule assembly mutant had a fitness defect in functionally TLR4(+) and TLR4(-) mice, suggesting a protective role of capsule in inflamed and noninflamed hosts. K1 capsule assembly and synthesis mutants had dramatically reduced IBC formation, demonstrating the common requirement for K1 polysaccharide in IBC development. The capsule assembly mutant appeared dispersed in the cytoplasm of the bladder epithelial cells and failed to undergo high-density intracellular replication during later stages of infection, when the wild-type strain continued to form serial generations of IBC. Deletion of the sialic acid regulator gene nanR partially restored IBC formation in the capsule assembly mutant. These data suggest that capsule is necessary for efficient IBC formation and that aberrant sialic acid accumulation, resulting from disruption of K1 capsule assembly, produces a NanR-mediated defect in intracellular proliferation and IBC development. Together, these data demonstrate the complex but important roles of UPEC polysaccharide encapsulation and sialic acid signaling in multiple stages of UTI pathogenesis.
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Abstract
The urinary tract is among the most common sites of bacterial infection, and Escherichia coli is by far the most common species infecting this site. Individuals at high risk for symptomatic urinary tract infection (UTI) include neonates, preschool girls, sexually active women, and elderly women and men. E. coli that cause the majority of UTIs are thought to represent only a subset of the strains that colonize the colon. E. coli strains that cause UTIs are termed uropathogenic E. coli (UPEC). In general, UPEC strains differ from commensal E. coli strains in that the former possess extragenetic material, often on pathogenicity-associated islands (PAIs), which code for gene products that may contribute to bacterial pathogenesis. Some of these genes allow UPEC to express determinants that are proposed to play roles in disease. These factors include hemolysins, secreted proteins, specific lipopolysaccharide and capsule types, iron acquisition systems, and fimbrial adhesions. The current dogma of bacterial pathogenesis identifies adherence, colonization, avoidance of host defenses, and damage to host tissues as events vital for achieving bacterial virulence. These considerations, along with analysis of the E. coli CFT073, UTI89, and 536 genomes and efforts to identify novel virulence genes should advance the field significantly and allow for the development of a comprehensive model of pathogenesis for uropathogenic E. coli.Further study of the adaptive immune response to UTI will be especially critical to refine our understanding and treatment of recurrent infections and to develop vaccines.
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Hawn TR, Scholes D, Li SS, Wang H, Yang Y, Roberts PL, Stapleton AE, Janer M, Aderem A, Stamm WE, Zhao LP, Hooton TM. Toll-like receptor polymorphisms and susceptibility to urinary tract infections in adult women. PLoS One 2009; 4:e5990. [PMID: 19543401 PMCID: PMC2696082 DOI: 10.1371/journal.pone.0005990] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2009] [Accepted: 05/26/2009] [Indexed: 12/05/2022] Open
Abstract
Background Although behavioral risk factors are strongly associated with urinary tract infection (UTI) risk, the role of genetics in acquiring this disease is poorly understood. Methodology/Principal Findings To test the hypothesis that polymorphisms in Toll-like receptor (TLR) pathway genes are associated with susceptibility to UTIs, we conducted a population-based case-control study of women ages 18–49 years. We examined DNA variants in 9 TLR pathway genes in 431 recurrent cystitis (rUTI) cases, 400 pyelonephritis cases, and 430 controls with no history of UTIs. In the Caucasian subgroup of 987 women, polymorphism TLR4_A896G was associated with protection from rUTI, but not pyelonephritis, with an odds ratio (OR) of 0.54 and a 95% confidence interval (CI) of 0.31 to 0.96. Polymorphism TLR5_C1174T, which encodes a variant that abrogates flagellin-induced signaling, was associated with an increased risk of rUTI (OR(95%CI): 1.81 (1.00–3.08)), but not pyelonephritis. Polymorphism TLR1_G1805T was associated with protection from pyelonephritis (OR(95%CI): 0.53 (0.29–0.96)). Conclusions These results provide the first evidence of associations of TLR5 and TLR1 variants with altered risks of acquiring rUTI and pyelonephritis, respectively. Although these data suggest that TLR polymorphisms are associated with adult susceptibility to UTIs, the statistical significance was modest and will require further study including validation with independent cohorts.
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Affiliation(s)
- Thomas R Hawn
- Department of Medicine, University of Washington, Seattle, Washington, United States of America.
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Weichhart T, Haidinger M, Hörl WH, Säemann MD. Current concepts of molecular defence mechanisms operative during urinary tract infection. Eur J Clin Invest 2008; 38 Suppl 2:29-38. [PMID: 18826479 DOI: 10.1111/j.1365-2362.2008.02006.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mucosal tissues such as the gastrointestinal tract are typically exposed to a tremendous number of microorganisms and many of them are potentially dangerous to the host. In contrast, the urogenital tract is rather infrequently colonized with bacterial organisms and also devoid of physical barriers as a multi-layered mucus or ciliated epithelia, thereby necessitating separate host defence mechanisms. Recurrent urinary tract infection (UTI) represents the successful case of microbial host evasion and poses a major medical and economic health problem. During recent years considerable advances have been made in our understanding of the mechanisms underlying the immune homeostasis of the urogenital tract. Hence, the system of pathogen-recognition receptors including the Toll-like receptors (TLRs) is able to sense danger signalling and thus activate the host immune system of the genitourinary tract. Additionally, various soluble antimicrobial molecules including iron-sequestering proteins, defensins, cathelicidin and Tamm-Horsfall protein (THP), as well as their role for the prevention of UTI by modulating innate and adaptive immunity, have been more clearly defined. Furthermore, signalling mediators like cyclic adenosine monophosphate (cAMP) or the circulatory hormone vasopressin were shown to be involved in the defence of uropathogenic microbes and maintenance of mucosal integrity. Beyond this, specific receptors e.g. CD46 or beta1/beta 3-integrins, have been elucidated that are hijacked by uropathogenic E. coli to enable invasion and survival within the urogenital system paving the way for chronic forms of urinary tract infection. Collectively, the majority of these findings offer novel avenues for basic and translational research implying effective therapies against the diverse forms of acute and chronic UTI.
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Affiliation(s)
- T Weichhart
- Department of Medicine III, Division of Nephrology and Dialysis, Medical University Vienna, Vienna, Austria
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The evolution of group-level pathogenic traits. J Theor Biol 2008; 253:355-62. [PMID: 18466926 DOI: 10.1016/j.jtbi.2008.03.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2007] [Revised: 03/16/2008] [Accepted: 03/17/2008] [Indexed: 11/22/2022]
Abstract
A group-selection model for the evolutionary origin of phase-variation in E. coli is proposed. Populations of commensal strains of E. coli populating mammalian hosts modulate its immune defenses through population-level control of the expression of fimbriae. At any time only a proportion of the population expresses these cell-surface adhesins. Collectively they elicit a host-based nutrient release if the fimbriae expression is low. Too high levels of fimbriation would provoke an inflammatory response and thus intolerable conditions for the cells. The optimal level of fimbriation is a group property and its evolution is difficult to explain by naive individual selection scenarios. This article presents a computational model to simulate the evolution of fimbriae. The two main conclusions of this contribution are: (i) the evolution of this group property requires the population to be partitioned into weakly interacting sub-populations. (ii) Given certain scenarios evolution consistently under-performs, in the sense that it does not find the optimal level of fimbriation.
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Svensson M, Irjala H, Svanborg C, Godaly G. Effects of epithelial and neutrophil CXCR2 on innate immunity and resistance to kidney infection. Kidney Int 2008; 74:81-90. [DOI: 10.1038/ki.2008.105] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Molecular basis of uropathogenic Escherichia coli evasion of the innate immune response in the bladder. Infect Immun 2008; 76:3891-900. [PMID: 18559433 DOI: 10.1128/iai.00069-08] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In the urinary tract, the innate immune system detects conserved bacterial components and responds to infection by activating the proinflammatory transcription factor NF-kappaB, resulting in cytokine secretion and neutrophil recruitment. Uropathogenic Escherichia coli (UPEC), however, has been shown to evade the host innate immune response by suppressing NF-kappaB activation in urothelial cells, which results in decreased cytokine secretion and increased urothelial apoptosis. To understand the molecular basis of UPEC modulation of inflammation, we performed a genetic screen with UPEC strain NU14 to identify genes which are required for modulation of urothelial cytokine secretion. Disruption of ampG (peptidoglycan permease), waaL (lipopolysaccharide O antigen ligase), or alr (alanine racemase) resulted in increased urothelial interleukin-8 (IL-8) and IL-6 release from urothelial cell cultures. Targeted deletion of these genes also resulted in elevated urothelial cytokine production during UPEC infection. Conditioned media from bacterial cultures of NU14 DeltaampG and NU14 DeltawaaL contained a heat-stable factor(s) which stimulated greater urothelial IL-8 secretion than that in NU14-conditioned medium. In a mouse model of urinary tract infection, NU14 DeltaampG, NU14 DeltawaaL, and NU14 Deltaalr were attenuated compared to wild-type NU14 and showed reduced fitness in competition experiments. Instillation of NU14 DeltaampG or NU14 DeltawaaL increased bladder neutrophil recruitment, indicating that enhanced urothelial cytokine secretion during urinary tract infection results in an altered host response. Thus, UPEC evasion of innate immune detection of bacterial components, such as lipopolysaccharide and peptidoglycan fragments, is likely an important factor in the ability of UPEC to colonize the urinary tract.
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Scherberich JE, Hartinger A. Impact of Toll-like receptor signalling on urinary tract infection. Int J Antimicrob Agents 2008; 31 Suppl 1:S9-14. [DOI: 10.1016/j.ijantimicag.2007.07.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 07/19/2007] [Indexed: 11/25/2022]
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Hilbert DW, Pascal KE, Libby EK, Mordechai E, Adelson ME, Trama JP. Uropathogenic Escherichia coli dominantly suppress the innate immune response of bladder epithelial cells by a lipopolysaccharide- and Toll-like receptor 4-independent pathway. Microbes Infect 2007; 10:114-21. [PMID: 18248759 DOI: 10.1016/j.micinf.2007.10.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 08/03/2007] [Accepted: 10/18/2007] [Indexed: 11/27/2022]
Abstract
Urinary tract infections are a major source of morbidity among women, with the majority caused by uropathogenic Escherichia coli. Our objective was to test if uropathogenic E. coli suppress the innate immune response of bladder epithelial cells. We found that bladder epithelial cells secrete interleukin-6 and interleukin-8 in response to non-pathogenic E. coli, whereas they failed to do so in response to uropathogenic E. coli. Uropathogenic E. coli prevented interleukin-6 secretion in response to non-pathogenic E. coli and a panel of Toll-like receptor agonists, as well as to interleukin-1beta, but not to tumor necrosis factor alpha. These results indicate that receptors with a Toll/interleukin-1 receptor domain are specifically targeted, and that suppression is not a consequence of toxicity. One candidate for mediating immune suppression is bacterial lipopolysaccharide. However, lipopolysaccharide isolated from either uropathogenic or non-pathogenic E. coli stimulated interleukin-6 secretion to similar levels. In addition, uropathogenic E. coli did not stimulate interleukin-6 secretion from cells expressing a dominant negative Toll-like receptor 4, and prevented cells lacking Toll-like receptor 4 from secreting interleukin-6 in response to synthetic lipoprotein. We conclude that uropathogenic E. coli suppress the innate immune response through a pathway partially independent of lipopolysaccharide and Toll-like receptor 4.
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Affiliation(s)
- David W Hilbert
- Research and Development Department, Medical Diagnostic Laboratories LLC, 2439 Kuser Rd., Hamilton, NJ 08690, USA
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Chromek M, Brauner A. Antimicrobial mechanisms of the urinary tract. J Mol Med (Berl) 2007; 86:37-47. [PMID: 17805504 DOI: 10.1007/s00109-007-0256-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 06/22/2007] [Accepted: 07/26/2007] [Indexed: 01/29/2023]
Abstract
The urinary tract is a key system to maintain the homeostasis of the human body. It is relatively open to the outside environment, the perineum, a region highly colonized by bacteria. Bacteria can even be found in urine of healthy individuals. Still, urinary tract infections are far less frequent than it could be expected under these conditions. The high resistance against such infections has been observed already more than 100 years ago. Since then, many antimicrobial mechanisms of the urinary tract have been elucidated. Some questions, however, remain challenges for patients, scientists and health care professionals. In this review, we try to summarize the achieved knowledge about mechanisms, maintaining the urinary tract free of infection. In addition, we discuss their relevance and possible clinical application.
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Affiliation(s)
- Milan Chromek
- Division of Clinical Microbiology, Department of Microbiology, Tumor and Cell Biology, Karolinska Hospital, Stockholm, Sweden
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40
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Billips BK, Forrestal SG, Rycyk MT, Johnson JR, Klumpp DJ, Schaeffer AJ. Modulation of host innate immune response in the bladder by uropathogenic Escherichia coli. Infect Immun 2007; 75:5353-60. [PMID: 17724068 PMCID: PMC2168307 DOI: 10.1128/iai.00922-07] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC), the most frequent cause of urinary tract infection (UTI), is associated with an inflammatory response which includes the induction of cytokine/chemokine secretion by urothelial cells and neutrophil recruitment to the bladder. Recent studies indicate, however, that UPEC can evade the early activation of urothelial innate immune response in vitro. In this study, we report that infection with the prototypic UPEC strain NU14 suppresses tumor necrosis factor alpha (TNF-alpha)-mediated interleukin-8 (CXCL-8) and interleukin-6 (CXCL-6) secretion from urothelial cell cultures compared to infection with a type 1 piliated E. coli K-12 strain. Furthermore, examination of a panel of clinical E. coli isolates revealed that 15 of 17 strains also possessed the ability to suppress cytokine secretion. In a murine model of UTI, NU14 infection resulted in diminished levels of mRNAs encoding keratinocyte-derived chemokine, macrophage inflammatory peptide 2, and CXCL-6 in the bladder relative to infection with an E. coli K-12 strain. Furthermore, reduced stimulation of inflammatory chemokine production during NU14 infection correlated with decreased levels of bladder and urine myeloperoxidase and increased bacterial colonization. These data indicate that a broad phylogenetic range of clinical E. coli isolates, including UPEC, may evade the activation of innate immune response in the urinary tract, thereby providing a pathogenic advantage.
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Affiliation(s)
- Benjamin K Billips
- Department of Urology, Northwestern University Feinberg School of Medicine, 16-703 Tarry, 303 East Chicago Avenue, Chicago, IL 60611, USA
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Bergsten G, Wullt B, Schembri MA, Leijonhufvud I, Svanborg C. Do type 1 fimbriae promote inflammation in the human urinary tract? Cell Microbiol 2007; 9:1766-81. [PMID: 17359236 DOI: 10.1111/j.1462-5822.2007.00912.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Type 1 fimbriae have been implicated as virulence factors in animal models of urinary tract infection (UTI), but the function in human disease remains unclear. This study used a human challenge model to examine if type 1 fimbriae trigger inflammation in the urinary tract. The asymptomatic bacteriuria strain Escherichia coli 83972, which fails to express type 1 fimbriae, due to a 4.25 kb fimB-fimD deletion, was reconstituted with a functional fim gene cluster and fimbrial expression was monitored through a gfp reporter. Each patient was inoculated with the fim+ or fim- variants on separate occasions, and the host response to type 1 fimbriae was quantified by intraindividual comparisons of the responses to the fim+ or fim- isogens, using cytokines and neutrophils as end-points. Type 1 fimbriae did not promote inflammation and adherence was poor, as examined on exfoliated cells in urine. This was unexpected, as type 1 fimbriae enhanced the inflammatory response to the same strain in the murine urinary tract and as P fimbrial expression by E. coli 83972 enhances adherence and inflammation in challenged patients. We conclude that type 1 fimbriae do not contribute to the mucosal inflammatory response in the human urinary tract.
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Affiliation(s)
- Göran Bergsten
- Department of Microbiology, Immunology, and Glycobiology, Lund University, Lund, Sweden
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42
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Sohanpal BK, Friar S, Roobol J, Plumbridge JA, Blomfield IC. Multiple co-regulatory elements and IHF are necessary for the control of fimB expression in response to sialic acid and N-acetylglucosamine in Escherichia coli K-12. Mol Microbiol 2007; 63:1223-36. [PMID: 17238917 DOI: 10.1111/j.1365-2958.2006.05583.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Expression of the FimB recombinase, and hence the OFF-to-ON switching of type 1 fimbriation in Escherichia coli, is inhibited by sialic acid (Neu(5)Ac) and by GlcNAc. NanR (Neu(5)Ac-responsive) and NagC (GlcNAc-6P-responsive) activate fimB expression by binding to operators (O(NR) and O(NC1) respectively) located more than 600 bp upstream of the fimB promoter within the large (1.4 kb) nanC-fimB intergenic region. Here it is demonstrated that NagC binding to a second site (O(NC2)), located 212 bp closer to fimB, also controls fimB expression, and that integration host factor (IHF), which binds midway between O(NC1) and O(NC2), facilitates NagC binding to its two operator sites. In contrast, IHF does not enhance the ability of NanR to activate fimB expression in the wild-type background. Neither sequences up to 820 bp upstream of O(NR), nor those 270 bp downstream of O(NC2), are required for activation by NanR and NagC. However, placing the NanR, IHF and NagC binding sites closer to the fimB promoter enhances the ability of the regulators to activate fimB expression. These results support a refined model for how two potentially key indicators of host inflammation, Neu(5)Ac and GlcNAc, regulate type 1 fimbriation.
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Affiliation(s)
- Baljinder K Sohanpal
- Biomedical Research Group, Department of Biosciences, University of Kent, Kent, UK
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Albiger B, Dahlberg S, Henriques-Normark B, Normark S. Role of the innate immune system in host defence against bacterial infections: focus on the Toll-like receptors. J Intern Med 2007; 261:511-28. [PMID: 17547708 DOI: 10.1111/j.1365-2796.2007.01821.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The innate immunity plays a critical role in host protection against pathogens and it relies amongst others on pattern recognition receptors such as the Toll-like receptors (TLRs) and the nucleotide-binding oligomerization domains proteins (NOD-like receptors, NLRs) to alert the immune system of the presence of invading bacteria. Since their recent discovery less than a decade ago, both TLRs and NLRs have been shown to be crucial in host protection against microbial infections but also in homeostasis of the colonizing microflora. They recognize specific microbial ligands and with the use of distinct adaptor molecules, they activate different signalling pathways that in turns trigger subsequent inflammatory and immune responses that allows a immediate response towards bacterial infections and the initiation of the long-lasting adaptive immunity. In this review, we will focus on the role of the TLRs against bacterial infections in humans in contrast to mice that have been used extensively in experimental models of infections and discuss their role in controlling normal flora or nonpathogenic bacteria. We also highlight how bacteria can evade recognition by TLRs.
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Affiliation(s)
- B Albiger
- Medical Microbiology, Department of Laboratory Medicine, Lund University, Malmö, Sweden
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44
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Andersen-Nissen E, Hawn TR, Smith KD, Nachman A, Lampano AE, Uematsu S, Akira S, Aderem A. Cutting edge: Tlr5-/- mice are more susceptible to Escherichia coli urinary tract infection. THE JOURNAL OF IMMUNOLOGY 2007; 178:4717-20. [PMID: 17404249 DOI: 10.4049/jimmunol.178.8.4717] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Although TLR5 regulates the innate immune response to bacterial flagellin, it is unclear whether its function is essential during in vivo murine infections. To examine this question, we challenged Tlr5(-/-) mice transurethrally with Escherichia coli. At 2 days postinfection, wild-type mice exhibited increased inflammation of the bladder in comparison to Tlr5(-/-) mice. By day 5 postinfection, Tlr5(-/-) mice had significantly more bacteria in the bladders and kidneys in comparison to wild-type mice and showed increased inflammation in both organs. In addition, flagellin induced high levels of cytokine and chemokine expression in the bladder that was dependent on TLR5. Together, these data represent the first evidence that TLR5 regulates the innate immune response in the urinary tract and is essential for an effective murine in vivo immune response to an extracellular pathogen.
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45
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Hogenkamp A, Herías MV, Tooten PCJ, Veldhuizen EJA, Haagsman HP. Effects of surfactant protein D on growth, adhesion and epithelial invasion of intestinal Gram-negative bacteria. Mol Immunol 2007; 44:3517-27. [PMID: 17477970 DOI: 10.1016/j.molimm.2007.03.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 03/09/2007] [Accepted: 03/14/2007] [Indexed: 11/21/2022]
Abstract
Surfactant protein D (SP-D) interacts with various different microorganisms and plays an important role in pulmonary innate immunity. SP-D expression has also been detected in extrapulmonary tissues, including the gastro-intestinal tract. However, its function in the intestine is unknown and may differ considerably from SP-D functions in the lung. Therefore, the effects of porcine SP-D (pSP-D) on several strains of intestinal bacteria were studied by means of bacterial growth assays, colony-count assays, radial diffusion assays and differential fluorescent staining. Furthermore, the effect of pSP-D on the adhesion- and invasion-characteristics was investigated. All bacterial strains tested in this study were aggregated by pSP-D, but only Escherichia coli K12 was susceptible to pSP-D-mediated growth inhibition. Bacterial membrane integrity of E. coli K12 was affected by pSP-D, but this did not lead to a reduced bacterial viability. Therefore, it is unlikely that pSP-D has a direct antimicrobial effect, and the observed effects are most likely due to pSP-D-mediated bacterial aggregation. The effects of pSP-D on bacterial adhesion and invasion were studied with the porcine intestinal epithelial cell line IPI-2I. Preincubation with pSP-D results in a several-fold increase in adhesion (E. coli and Salmonella) and invasion (Salmonella), but did not affect the IL-8 production induced by the bacteria. Results obtained in this study suggest that pSP-D promotes uptake of pathogenic bacteria by epithelial cells. This may reflect a scavenger function for pSP-D in the intestine, which enables the host to generate a more rapid response to infectious bacteria.
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Affiliation(s)
- Astrid Hogenkamp
- Department of Infectious Diseases and Immunology, Division Molecular Host Defence, Graduate School of Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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46
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Abstract
Urinary tract infections (UTIs) remain a significant clinical problem, despite antibiotic treatment and surgical correction of reflux and malformations. Here we propose that novel molecular tools may be applied to modernize and individualize the diagnosis and therapy of UTI. Determinants of bacterial virulence and host resistance are relatively well understood at the molecular level, and technology for their detection is within reach.
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Affiliation(s)
- G Godaly
- Institute of Laboratory Medicine, Department of Microbiology, Immunology and Glycobiology, Lund University, Lund, Sweden
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47
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Lee HK, Iwasaki A. Innate control of adaptive immunity: Dendritic cells and beyond. Semin Immunol 2007; 19:48-55. [PMID: 17276695 DOI: 10.1016/j.smim.2006.12.001] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2006] [Accepted: 12/10/2006] [Indexed: 12/25/2022]
Abstract
Innate immune recognition of pathogens triggers both immediate defenses against the invading pathogens and the initiation of adaptive immune responses. Dendritic cells (DCs) play a key role in sensing and processing microbial information and directing the differentiation of naïve lymphocytes to effector cells suitable against particular types of infections. These processes within DCs are intricately controlled at the levels of the cell, anatomical location, migration and their interaction with other cell types. This review focuses on recent understanding of the contributions of several key cell types, which regulate, and are regulated by DCs, in the generation of adaptive immune responses.
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Affiliation(s)
- Heung Kyu Lee
- Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
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Månsson LE, Kjäll P, Pellett S, Nagy G, Welch RA, Bäckhed F, Frisan T, Richter-Dahlfors A. Role of the lipopolysaccharide-CD14 complex for the activity of hemolysin from uropathogenic Escherichia coli. Infect Immun 2007; 75:997-1004. [PMID: 17101668 PMCID: PMC1828525 DOI: 10.1128/iai.00957-06] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Revised: 09/19/2006] [Accepted: 10/31/2006] [Indexed: 11/20/2022] Open
Abstract
Bacterial pathogens produce a variety of exotoxins, which often become associated with the bacterial outer membrane component lipopolysaccharide (LPS) during their secretion. LPS is a potent proinflammatory mediator; however, it is not known whether LPS contributes to cell signaling induced by those microbial components to which it is attached. This is partly due to the common view that LPS present in bacterial component preparations is an experimental artifact. The Escherichia coli exotoxin hemolysin (Hly) is a known inducer of proinflammatory signaling in epithelial cells, and the signal transduction pathway involves fluctuation of the intracellular-Ca(2+) concentration. Since LPS is known to interact with Hly, we investigated whether it is required as a cofactor for the activity of Hly. We found that the LPS/Hly complex exploits the CD14/LPS-binding protein recognition system to bring Hly to the cell membrane, where intracellular-Ca(2+) signaling is initiated via specific activation of the small GTPase RhoA. Hly-induced Ca(2+) signaling was found to occur independently of the LPS receptor TLR4, suggesting that the role of LPS/CD14 is to deliver Hly to the cell membrane. In contrast, the cytolytic effect triggered by exposure of cells to high Hly concentrations occurs independently of LPS/CD14. Collectively, our data reveal a novel molecular mechanism for toxin delivery in bacterial pathogenesis, where LPS-associated microbial compounds are targeted to the host cell membrane as a consequence of their association with LPS.
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Affiliation(s)
- Lisa E Månsson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, S-17177 Stockholm, Sweden
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Godaly G, Otto G, Burdick MD, Strieter RM, Svanborg C. Fimbrial lectins influence the chemokine repertoire in the urinary tract mucosa. Kidney Int 2007; 71:778-86. [PMID: 17228365 DOI: 10.1038/sj.ki.5002076] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The defense against mucosal infections relies on chemokines that recruit inflammatory cells to the mucosa. This study examined if the chemokine response to uro-pathogenic Escherichia coli is influenced by fimbrial expression. The CXC (CXCL1, CXCL5, CXCL8, CXCL9, CXCL10) and CC chemokines (CCL2, CCL3, CCL5) were quantified after in vitro infection of uro-epithelial cells with a fimbriated E. coli pyelonephritis isolate, or with P or type 1 fimbriated transformants of an avirulent E. coli K-12 strain. The response profile was shown to vary with the fimbrial type. Type 1 fimbriated E. coli elicited mainly CXCL1 and CXCL8, whereas P fimbriated E. coli stimulated CCL2 and CCL5 and class II were more potent chemokine inducers than class III P fimbriae. Chemokines were also quantified in urine samples from 73 patients with febrile urinary tract infection, and analyzed as a function of disease severity and fimbrial expression by the strain infecting each patient. A complex CXC and CC chemokine response was detected in patient urine, with a significant influence of the fimbrial type. The results show that virulence factors like fimbriae may modify the mucosal chemokine response. This mechanism may allow the host to adjust the inflammatory cell infiltrate to fit the infecting strain.
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Affiliation(s)
- G Godaly
- Department of MIG, Division of Laboratory Medicine, Lund University, Lund, Sweden.
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50
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Fischer H, Ellström P, Ekström K, Gustafsson L, Gustafsson M, Svanborg C. Ceramide as a TLR4 agonist; a putative signalling intermediate between sphingolipid receptors for microbial ligands and TLR4. Cell Microbiol 2007; 9:1239-51. [PMID: 17223929 DOI: 10.1111/j.1462-5822.2006.00867.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mucosal Toll-like receptors (TLRs) respond to pathogens, but remain inert to the indigenous flora, suggesting that the TLRs can receive pathogen-specific signals. For example, TLR4 signalling is activated in CD14-negative epithelial cells by P-fimbriated, uropathogenic Escherichia coli, but not by lipopolysaccharide. The fimbriae use glycosphingolipids as recognition receptors and there is release of ceramide, which is the membrane-anchoring domain of the receptors. In this study, ceramide was identified as a TLR4 agonist and as a putative signalling intermediate between the glycosphingolipid recognition receptors and TLR4. Exogenous ceramide activated a TLR4-dependent epithelial cell response, as shown by exposing stably transfected TLR4-positive or -negative human embryonal kidney cells to C2 and C6 ceramide. A similar, TLR4-dependent response occurred after deliberate release of endogenous long-chained ceramide with sphingomyelinase. Microbial ligands with glycosphingolipid specificity (P fimbriae or the B subunit of Shiga toxin) were shown to increase the levels of ceramide and to trigger a TLR4-dependent response in epithelial cells. The results show that ceramide activates TLR4 signalling and suggest that this mechanism might allow pathogens to elicit mucosal TLR4 responses by perturbing sphingolipid receptors for virulence ligands like P fimbriae.
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Affiliation(s)
- Hans Fischer
- Department of Microbiology, Immunology and Glycobiology, Institute of Laboratory Medicine, Lund University, Sölvegatan 23, S-22362 Lund, Sweden
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