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Yu H, Xu Y, Imani S, Zhao Z, Ullah S, Wang Q. Navigating ESKAPE Pathogens: Considerations and Caveats for Animal Infection Models Development. ACS Infect Dis 2024; 10:2336-2355. [PMID: 38866389 PMCID: PMC11249778 DOI: 10.1021/acsinfecdis.4c00007] [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: 01/04/2024] [Revised: 05/19/2024] [Accepted: 05/29/2024] [Indexed: 06/14/2024]
Abstract
The misuse of antibiotics has led to the global spread of drug-resistant bacteria, especially multi-drug-resistant (MDR) ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). These opportunistic bacteria pose a significant threat, in particular within hospitals, where they cause nosocomial infections, leading to substantial morbidity and mortality. To comprehensively explore ESKAPE pathogenesis, virulence, host immune response, diagnostics, and therapeutics, researchers increasingly rely on necessitate suitable animal infection models. However, no single model can fully replicate all aspects of infectious diseases. Notably when studying opportunistic pathogens in immunocompetent hosts, rapid clearance by the host immune system can limit the expression of characteristic disease symptoms. In this study, we examine the critical role of animal infection models in understanding ESKAPE pathogens, addressing limitations and research gaps. We discuss applications and highlight key considerations for effective models. Thoughtful decisions on disease replication, parameter monitoring, and data collection are crucial for model reliability. By meticulously replicating human diseases and addressing limitations, researchers maximize the potential of animal infection models. This aids in targeted therapeutic development, bridges knowledge gaps, and helps combat MDR ESKAPE pathogens, safeguarding public health.
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Affiliation(s)
- Haojie Yu
- Key
Laboratory of Artificial Organs and Computational Medicine in Zhejiang
Province, Key Laboratory of Pollution Exposure and Health Intervention
of Zhejiang Province, Shulan International Medical College, Zhejiang Shuren University, Hangzhou 310015, Zhejiang China
- Stomatology
Hospital, School of Stomatology, Zhejiang University School of Medicine,
Zhejiang Provincial Clinical Research Center for Oral Diseases, Key
Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou 310006, China
| | - Yongchang Xu
- Key
Laboratory of Aging and Cancer Biology of Zhejiang Province, School
of Basic Medical Sciences, Hangzhou Normal
University, Hangzhou 311121, China
| | - Saber Imani
- Shulan
International Medical College, Zhejiang
Shuren University, Hangzhou 310015, Zhejiang China
| | - Zhuo Zhao
- Department
of Computer Science and Engineering, University
of Notre Dame, Notre
Dame, Indiana 46556, United States
| | - Saif Ullah
- Department
of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, United States
| | - Qingjing Wang
- Key
Laboratory of Artificial Organs and Computational Medicine in Zhejiang
Province, Key Laboratory of Pollution Exposure and Health Intervention
of Zhejiang Province, Shulan International Medical College, Zhejiang Shuren University, Hangzhou 310015, Zhejiang China
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2
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Ansari I, Mandal A, Kansal K, Walling P, Khan S, Aijaz S. The C-terminal proline-rich repeats of Enteropathogenic E. coli effector EspF are sufficient for the depletion of tight junction membrane proteins and interactions with early and recycling endosomes. Gut Pathog 2024; 16:36. [PMID: 38972985 PMCID: PMC11229284 DOI: 10.1186/s13099-024-00626-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 06/28/2024] [Indexed: 07/09/2024] Open
Abstract
BACKGROUND Enteropathogenic E. coli (EPEC) causes acute infantile diarrhea accounting for significant morbidity and mortality in developing countries. EPEC uses a type three secretion system to translocate more than twenty effectors into the host intestinal cells. At least four of these effectors, namely EspF, Map, EspG1/G2 and NleA, are reported to disrupt the intestinal tight junction barrier. We have reported earlier that the expression of EspF and Map in MDCK cells causes the depletion of the TJ membrane proteins and compromises the integrity of the intestinal barrier. In the present study, we have examined the role of the proline-rich repeats (PRRs) within the C-terminus of EspF in the depletion of the tight junction membrane proteins and identified key endocytosis markers that interact with EspF via these repeats. RESULTS We generated mutant EspF proteins which lacked one or more proline-rich repeats (PRRs) from the N-terminus of EspF and examined the effect of their expression on the cellular localization of tight junction membrane proteins. In lysates derived from cells expressing the mutant EspF proteins, we found that the C-terminal PRRs of EspF are sufficient to cause the depletion of TJ membrane proteins. Pull-down assays revealed that the PRRs mediate interactions with the TJ adaptor proteins ZO-1 and ZO-2 as well as with the proteins involved in endocytosis such as caveolin-1, Rab5A and Rab11. CONCLUSIONS Our study demonstrates the direct role of the proline-rich repeats of EspF in the depletion of the TJ membrane proteins and a possible involvement of the PRRs in the endocytosis of host proteins. New therapeutic strategies can target these PRR domains to prevent intestinal barrier dysfunction in EPEC infections.
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Affiliation(s)
- Imran Ansari
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Anupam Mandal
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Kritika Kansal
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Pangertoshi Walling
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Sumbul Khan
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Saima Aijaz
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India.
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3
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Miner MV, Rauch I. Why put yourself on a pedestal? The pathogenic role of the A/E pedestal. Infect Immun 2024:e0048923. [PMID: 38591884 DOI: 10.1128/iai.00489-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024] Open
Abstract
Certain Escherichia coli (E. coli) strains are attaching and effacing (A/E) lesion pathogens that primarily infect intestinal epithelial cells. They cause actin restructuring and polymerization within the host cell to create an actin-rich protrusion below the site of adherence, termed the pedestal. Although there is clarity on the pathways initiating pedestal formation, the underlying purpose(s) of the pedestal remains ambiguous. The conservation of pedestal-forming activity across multiple pathogens and redundancy in formation pathways indicate a pathogenic advantage. However, few decisive conclusions have been drawn, given that the results vary between model systems. Some research argues that the pedestal increases the colonization capability of the bacterium. These studies utilize A/E pathogens specifically deficient in pedestal formation to evaluate adhesion and intestinal colonization following infection. There have been many proposed mechanisms for the colonization benefit conferred by the pedestal. One suggested benefit is that the pedestal allows for direct cytosolic anchoring through incorporation of the established host cortical actin, causing a stable link between the pathogen and cell structure. The pedestal may confer enhanced motility, as enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) are better able to migrate on the surface of host cells and infect neighboring cells in the presence of the pedestal. Additionally, some research suggests that the pedestal improves effector delivery. This review will investigate the purpose of pedestal formation using evidence from recent literature and will critically evaluate the methodology and model systems. Most importantly, we will contextualize the proposed functions to reconcile potential synergistic effects.
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Affiliation(s)
- M V Miner
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | - I Rauch
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
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4
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Scott SA, Fu J, Chang PV. Dopamine receptor D2 confers colonization resistance via microbial metabolites. Nature 2024; 628:180-185. [PMID: 38480886 PMCID: PMC11097147 DOI: 10.1038/s41586-024-07179-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 02/07/2024] [Indexed: 03/26/2024]
Abstract
The gut microbiome has major roles in modulating host physiology. One such function is colonization resistance, or the ability of the microbial collective to protect the host against enteric pathogens1-3, including enterohaemorrhagic Escherichia coli (EHEC) serotype O157:H7, an attaching and effacing (AE) food-borne pathogen that causes severe gastroenteritis, enterocolitis, bloody diarrhea and acute renal failure4,5 (haemolytic uremic syndrome). Although gut microorganisms can provide colonization resistance by outcompeting some pathogens or modulating host defence provided by the gut barrier and intestinal immune cells6,7, this phenomenon remains poorly understood. Here, we show that activation of the neurotransmitter receptor dopamine receptor D2 (DRD2) in the intestinal epithelium by gut microbial metabolites produced upon dietary supplementation with the essential amino acid L-tryptophan protects the host against Citrobacter rodentium, a mouse AE pathogen that is widely used as a model for EHEC infection8,9. We further find that DRD2 activation by these tryptophan-derived metabolites decreases expression of a host actin regulatory protein involved in C. rodentium and EHEC attachment to the gut epithelium via formation of actin pedestals. Our results reveal a noncanonical colonization resistance pathway against AE pathogens that features an unconventional role for DRD2 outside the nervous system in controlling actin cytoskeletal organization in the gut epithelium. Our findings may inspire prophylactic and therapeutic approaches targeting DRD2 with dietary or pharmacological interventions to improve gut health and treat gastrointestinal infections, which afflict millions globally.
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Affiliation(s)
- Samantha A Scott
- Department of Microbiology, Cornell University, Ithaca, NY, USA
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY, USA
| | - Jingjing Fu
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY, USA
| | - Pamela V Chang
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY, USA.
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA.
- Cornell Center for Immunology, Cornell University, Ithaca, NY, USA.
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, USA.
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5
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Rosay T, Jimenez AG, Sperandio V. Glucuronic acid confers colonization advantage to enteric pathogens. Proc Natl Acad Sci U S A 2024; 121:e2400226121. [PMID: 38502690 PMCID: PMC10990124 DOI: 10.1073/pnas.2400226121] [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: 01/04/2024] [Accepted: 02/26/2024] [Indexed: 03/21/2024] Open
Abstract
Glucuronidation is a detoxification process to eliminate endo- and xeno-biotics and neurotransmitters from the host circulation. Glucuronosyltransferase binds these compounds to glucuronic acid (GlcA), deactivating them and allowing their elimination through the gastrointestinal (GI) tract. However, the microbiota produces β-glucuronidases that release GlcA and reactivate these compounds. Enteric pathogens such as enterohemorrhagic Escherichia coli (EHEC) and Citrobacter rodentium sense and utilize galacturonic acid (GalA), an isomer of GlcA, to outcompete the microbiota promoting gut colonization. However, the role of GlcA in pathogen colonization has not been explored. Here, we show that treatment of mice with a microbial β-glucuronidase inhibitor (GUSi) decreased C. rodentium's colonization of the GI tract, without modulating bacterial virulence or host inflammation. Metagenomic studies indicated that GUSi did not change the composition of the intestinal microbiota in these animals. GlcA confers an advantage for pathogen expansion through its utilization as a carbon source. Congruently mutants unable to catabolize GlcA depict lower GI colonization compared to wild type and are not sensitive to GUSi. Germfree mice colonized with a commensal E. coli deficient for β-glucuronidase production led to a decrease of C. rodentium tissue colonization, compared to animals monocolonized with an E. coli proficient for production of this enzyme. GlcA is not sensed as a signal and doesn't activate virulence expression but is used as a metabolite. Because pathogens can use GlcA to promote their colonization, inhibitors of microbial β-glucuronidases could be a unique therapeutic against enteric infections without disturbing the host or microbiota physiology.
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Affiliation(s)
- Thibaut Rosay
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI53706
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Angel G. Jimenez
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Vanessa Sperandio
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI53706
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX75390
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6
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L A LA, Waturangi DE. Application of BI-EHEC and BI-EPEC bacteriophages to control enterohemorrhagic and enteropathogenic escherichia coli on various food surfaces. BMC Res Notes 2023; 16:102. [PMID: 37312167 DOI: 10.1186/s13104-023-06371-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 05/25/2023] [Indexed: 06/15/2023] Open
Abstract
OBJECTIVES The purposes of this study were to determine the Efficiency of Plating (EOP) value of Bacteriophage BI-EHEC and BI-EPEC and to evaluate the application of these bacteriophages in reducing population of EHEC and EPEC on various food samples. RESULTS In this study, we used bacteriophage BI-EHEC and BI-EPEC, which were isolated from previous study. Both phages were tested with other multiple pathotypes of intestinal pathogenic E. coli to determine the efficiency of plating. BI-EHEC had high efficiency toward ETEC with an EOP value of 2.95 but low efficiency toward EHEC with an EOP value of 0.10, while BI-EPEC had high efficiency toward EHEC and ETEC with EOP values of 1.10 and 1.21, respectively. As biocontrol agents, both bacteriophages able to reduce CFU of EHEC and EPEC in several food samples using 1 and 6-days incubation times at 4 [Formula: see text]. BI-EHEC reduced the number of EHEC with an overall percentage of bacterial reduction value above 0.13 log10, while BI-EPEC reduced number of EPEC with reduction value above 0.33 log10.
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Affiliation(s)
- Leny Agustina L A
- Faculty of Biotechnology, Atma Jaya Catholic University of Indonesia, Jalan Jenderal Sudirman 51 Jakarta, 12930, South Jakarta, Indonesia
| | - Diana Elizabeth Waturangi
- Faculty of Biotechnology, Atma Jaya Catholic University of Indonesia, Jalan Jenderal Sudirman 51 Jakarta, 12930, South Jakarta, Indonesia.
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7
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Scott SA, Fu J, Chang PV. Dopamine receptor D2 confers colonization resistance via gut microbial metabolites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.14.532647. [PMID: 36993486 PMCID: PMC10055168 DOI: 10.1101/2023.03.14.532647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
The gut microbiome plays major roles in modulating host physiology. One such function is colonization resistance, or the ability of the microbial collective to protect the host against enteric pathogens1-3, including enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7, an attaching and effacing (AE) food-borne pathogen that causes severe gastroenteritis, enterocolitis, bloody diarrhea, and acute renal failure (hemolytic uremic syndrome)4,5. Although gut microbes can provide colonization resistance by outcompeting some pathogens or modulating host defense provided by the gut barrier and intestinal immune cells, this phenomenon remains poorly understood. Emerging evidence suggests that small-molecule metabolites produced by the gut microbiota may mediate this process6. Here, we show that tryptophan (Trp)-derived metabolites produced by the gut bacteria protect the host against Citrobacter rodentium, a murine AE pathogen widely used as a model for EHEC infection7,8, by activation of the host neurotransmitter dopamine receptor D2 (DRD2) within the intestinal epithelium. We further find that these Trp metabolites act through DRD2 to decrease expression of a host actin regulatory protein involved in C. rodentium and EHEC attachment to the gut epithelium via formation of actin pedestals. Previously identified mechanisms of colonization resistance either directly affect the pathogen by competitive exclusion or indirectly by modulation of host defense mechanisms9,10, so our results delineate a noncanonical colonization resistance pathway against AE pathogens featuring an unconventional role for DRD2 outside the nervous system in controlling actin cytoskeletal organization within the gut epithelium. Our findings may inspire prophylactic and therapeutic approaches for improving gut health and treating gastrointestinal infections, which afflict millions globally.
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Affiliation(s)
- Samantha A. Scott
- Department of Microbiology, Cornell University, Ithaca, NY 14853
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853
| | - Jingjing Fu
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853
| | - Pamela V. Chang
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853
- Cornell Center for Immunology, Cornell University, Ithaca, NY 14853
- Cornell Institute of Host-Microbe Interactions & Disease, Cornell University, Ithaca, NY 14853
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8
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Interactions between Enterohemorrhagic Escherichia coli (EHEC) and Gut Commensals at the Interface of Human Colonoids. mBio 2022; 13:e0132122. [PMID: 35638758 PMCID: PMC9239246 DOI: 10.1128/mbio.01321-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The interactions between the gut microbiota and pathogens are complex and can determine the outcome of an infection. Enterohemorrhagic Escherichia coli (EHEC) is a major human enteric pathogen that colonizes the colon through attaching and effacing (AE) lesions and uses microbiota-derived molecules as cues to control its virulence. Different gut commensals can modulate EHEC virulence. However, the lack of an animal model that recapitulates the human pathophysiology of EHEC infection makes it challenging to investigate how variations in microbiota composition could affect host susceptibility to this pathogen. Here, we addressed these interactions building from simple to more complex in vitro systems, culminating with the use of the physiological relevant human colonoids as a model to study the interactions between EHEC and different gut commensals. We demonstrated that Bacteroides thetaiotaomicron and Enterococcus faecalis enhance virulence expression and AE lesion formation in cultured epithelial cells, as well as on the colonic epithelium, while commensal E. coli did not affect these phenotypes. Importantly, in the presence of these three commensals together, virulence and AE lesion are enhanced. Moreover, we identified specific changes in the metabolic landscape promoted by different members of the gut microbiota and showed that soluble factors released by E. faecalis can increase EHEC virulence gene expression. Our study highlights the importance of interspecies bacterial interactions and chemical exchange in the modulation of EHEC virulence.
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9
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Khan I, Bai Y, Zha L, Ullah N, Ullah H, Shah SRH, Sun H, Zhang C. Mechanism of the Gut Microbiota Colonization Resistance and Enteric Pathogen Infection. Front Cell Infect Microbiol 2022; 11:716299. [PMID: 35004340 PMCID: PMC8733563 DOI: 10.3389/fcimb.2021.716299] [Citation(s) in RCA: 75] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 11/26/2021] [Indexed: 12/26/2022] Open
Abstract
The mammalian gut microbial community, known as the gut microbiota, comprises trillions of bacteria, which co-evolved with the host and has an important role in a variety of host functions that include nutrient acquisition, metabolism, and immunity development, and more importantly, it plays a critical role in the protection of the host from enteric infections associated with exogenous pathogens or indigenous pathobiont outgrowth that may result from healthy gut microbial community disruption. Microbiota evolves complex mechanisms to restrain pathogen growth, which included nutrient competition, competitive metabolic interactions, niche exclusion, and induction of host immune response, which are collectively termed colonization resistance. On the other hand, pathogens have also developed counterstrategies to expand their population and enhance their virulence to cope with the gut microbiota colonization resistance and cause infection. This review summarizes the available literature on the complex relationship occurring between the intestinal microbiota and enteric pathogens, describing how the gut microbiota can mediate colonization resistance against bacterial enteric infections and how bacterial enteropathogens can overcome this resistance as well as how the understanding of this complex interaction can inform future therapies against infectious diseases.
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Affiliation(s)
- Israr Khan
- School of Life Sciences, Lanzhou University, Lanzhou, China.,Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, Lanzhou University, Lanzhou, China.,Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, Lanzhou, China.,Gansu Key Laboratory of Functional Genomics and Molecular Diagnosis, Lanzhou University, Lanzhou, China.,Cuiying Biomedical Research Centre, Lanzhou University Second Hospital, Lanzhou, China
| | - Yanrui Bai
- School of Life Sciences, Lanzhou University, Lanzhou, China.,Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, Lanzhou University, Lanzhou, China.,Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, Lanzhou, China.,Gansu Key Laboratory of Functional Genomics and Molecular Diagnosis, Lanzhou University, Lanzhou, China.,Cuiying Biomedical Research Centre, Lanzhou University Second Hospital, Lanzhou, China
| | - Lajia Zha
- School of Life Sciences, Lanzhou University, Lanzhou, China.,Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, Lanzhou University, Lanzhou, China.,Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, Lanzhou, China.,Gansu Key Laboratory of Functional Genomics and Molecular Diagnosis, Lanzhou University, Lanzhou, China.,Cuiying Biomedical Research Centre, Lanzhou University Second Hospital, Lanzhou, China
| | - Naeem Ullah
- School of Life Sciences, Lanzhou University, Lanzhou, China.,Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, Lanzhou University, Lanzhou, China.,Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, Lanzhou, China
| | - Habib Ullah
- School of Life Sciences, Lanzhou University, Lanzhou, China.,Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, Lanzhou University, Lanzhou, China.,Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, Lanzhou, China.,Cuiying Biomedical Research Centre, Lanzhou University Second Hospital, Lanzhou, China
| | - Syed Rafiq Hussain Shah
- Department of Microecology, School of Basic Medical Sciences, Dalian Medical University, Dalian, China
| | - Hui Sun
- Cuiying Biomedical Research Centre, Lanzhou University Second Hospital, Lanzhou, China
| | - Chunjiang Zhang
- School of Life Sciences, Lanzhou University, Lanzhou, China.,Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, Lanzhou University, Lanzhou, China.,Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, Lanzhou, China.,Gansu Key Laboratory of Functional Genomics and Molecular Diagnosis, Lanzhou University, Lanzhou, China
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10
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Subramaniam S, Joyce P, Thomas N, Prestidge CA. Bioinspired drug delivery strategies for repurposing conventional antibiotics against intracellular infections. Adv Drug Deliv Rev 2021; 177:113948. [PMID: 34464665 DOI: 10.1016/j.addr.2021.113948] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 08/04/2021] [Accepted: 08/23/2021] [Indexed: 12/11/2022]
Abstract
Bacteria have developed a wealth of strategies to avoid and resist the action of antibiotics, one of which involves pathogens invading and forming reservoirs within host cells. Due to the poor cell membrane permeability, stability and retention of conventional antibiotics, this renders current treatments largely ineffective, since achieving a therapeutically relevant antibiotic concentration at the site of intracellular infection is not possible. To overcome such challenges, current antibiotics are 'repurposed' via reformulation using micro- or nano-carrier systems that effectively encapsulate and deliver therapeutics across cellular membranes of infected cells. Bioinspired materials that imitate the uptake of biological particulates and release antibiotics in response to natural stimuli are recently explored to improve the targeting and specificity of this 'nanoantibiotic' approach. In this review, the mechanisms of internalization and survival of intracellular bacteria are elucidated, effectively accentuating the current treatment challenges for intracellular infections and the implications for repurposing conventional antibiotics. Key case studies of nanoantibiotics that have drawn inspiration from natural biological particles and cellular uptake pathways to effectively eradicate intracellular pathogens are detailed, clearly highlighting the rational for harnessing bioinspired drug delivery strategies.
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Affiliation(s)
- Santhni Subramaniam
- University of South Australia, UniSA Clinical and Health Sciences, SA 5000, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of South Australia, Adelaide, SA 5000, Australia
| | - Paul Joyce
- University of South Australia, UniSA Clinical and Health Sciences, SA 5000, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of South Australia, Adelaide, SA 5000, Australia
| | - Nicky Thomas
- University of South Australia, UniSA Clinical and Health Sciences, SA 5000, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of South Australia, Adelaide, SA 5000, Australia; The Basil Hetzel Institute for Translational Health Research, Woodville, SA 5011, Australia
| | - Clive A Prestidge
- University of South Australia, UniSA Clinical and Health Sciences, SA 5000, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of South Australia, Adelaide, SA 5000, Australia.
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11
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Caballero-Flores G, Pickard JM, Núñez G. Regulation of Citrobacter rodentium colonization: virulence, immune response and microbiota interactions. Curr Opin Microbiol 2021; 63:142-149. [PMID: 34352594 DOI: 10.1016/j.mib.2021.07.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 01/07/2023]
Abstract
Citrobacter rodentium is a mouse-specific pathogen commonly used to model infection by human Enteropathogenic Escherichia coli, an important cause of infant diarrhea and mortality worldwide. In the early phase of infection, C. rodentium overcomes competition by the gut microbiota for successful replication. Then, the pathogen uses a type three secretion system (T3SS) to inject effector proteins into intestinal epithelial cells and induce metabolic and inflammatory conditions that promote colonization of the intestinal epithelium. C. rodentium also elicits highly coordinated innate and adaptive immune responses in the gut that regulate pathogen colonization and eradication. In this review, we highlight recent work on the regulation and function of the C. rodentium T3SS, the mechanisms employed by the pathogen to evade competition by the microbiota, and the function of the host immune response against infection.
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Affiliation(s)
- Gustavo Caballero-Flores
- Department of Pathology and Rogel Cancer Center, The University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Joseph M Pickard
- Department of Pathology and Rogel Cancer Center, The University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Gabriel Núñez
- Department of Pathology and Rogel Cancer Center, The University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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12
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Atypical Enteropathogenic Escherichia coli: from Kittens to Humans and Beyond! Infect Immun 2021; 89:IAI.00752-20. [PMID: 33361199 DOI: 10.1128/iai.00752-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Atypical enteropathogenic Escherichia coli (aEPEC) are associated with diarrhea worldwide, yet genome-wide investigations to probe their virulome are lacking. In this issue of Infection and Immunity, V. E. Watson, T. H. Hazen, D. A. Rasko, M. E. Jacob, et al. (IAI 89:e00619-20, 2020, https://doi.org/10.1128/IAI.00619-20) sequenced aEPEC isolates from diarrheic and asymptomatic kittens. Using phylogenomics, they demonstrated that these isolates were genetically indistinguishable from human isolates, suggesting that kittens may serve as a reservoir and, perhaps, a much-needed model to interrogate aEPEC virulence. The diarrheic isolates were hypermotile, suggesting that this phenotype may distinguish virulent strains from their innocuous counterparts.
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13
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Ledwaba SE, Costa DVS, Bolick DT, Giallourou N, Medeiros PHQS, Swann JR, Traore AN, Potgieter N, Nataro JP, Guerrant RL. Enteropathogenic Escherichia coli Infection Induces Diarrhea, Intestinal Damage, Metabolic Alterations, and Increased Intestinal Permeability in a Murine Model. Front Cell Infect Microbiol 2020; 10:595266. [PMID: 33392105 PMCID: PMC7773950 DOI: 10.3389/fcimb.2020.595266] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 11/11/2020] [Indexed: 12/15/2022] Open
Abstract
Enteropathogenic E. coli (EPEC) are recognized as one of the leading bacterial causes of infantile diarrhea worldwide. Weaned C57BL/6 mice pretreated with antibiotics were challenged orally with wild-type EPEC or escN mutant (lacking type 3 secretion system) to determine colonization, inflammatory responses and clinical outcomes during infection. Antibiotic disruption of intestinal microbiota enabled efficient colonization by wild-type EPEC resulting in growth impairment and diarrhea. Increase in inflammatory biomarkers, chemokines, cellular recruitment and pro-inflammatory cytokines were observed in intestinal tissues. Metabolomic changes were also observed in EPEC infected mice with changes in tricarboxylic acid (TCA) cycle intermediates, increased creatine excretion and shifts in gut microbial metabolite levels. In addition, by 7 days after infection, although weights were recovering, EPEC-infected mice had increased intestinal permeability and decreased colonic claudin-1 levels. The escN mutant colonized the mice with no weight loss or increased inflammatory biomarkers, showing the importance of the T3SS in EPEC virulence in this model. In conclusion, a murine infection model treated with antibiotics has been developed to mimic clinical outcomes seen in children with EPEC infection and to examine potential roles of selected virulence traits. This model can help in further understanding mechanisms involved in the pathogenesis of EPEC infections and potential outcomes and thus assist in the development of potential preventive or therapeutic interventions.
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Affiliation(s)
- Solanka E. Ledwaba
- Department of Microbiology, University of Venda, Thohoyandou, South Africa
| | - Deiziane V. S. Costa
- Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, Brazil
| | - David T. Bolick
- Center for Global Health, Division of Infectious Disease and International Health, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Natasa Giallourou
- Faculty of Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College, London, England
| | | | - Jonathan R. Swann
- Faculty of Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College, London, England
| | - Afsatou N. Traore
- Department of Microbiology, University of Venda, Thohoyandou, South Africa
| | - Natasha Potgieter
- Department of Microbiology, University of Venda, Thohoyandou, South Africa
| | - James P. Nataro
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Richard L. Guerrant
- Center for Global Health, Division of Infectious Disease and International Health, University of Virginia School of Medicine, Charlottesville, VA, United States
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14
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Yang W, Yu T, Huang X, Bilotta AJ, Xu L, Lu Y, Sun J, Pan F, Zhou J, Zhang W, Yao S, Maynard CL, Singh N, Dann SM, Liu Z, Cong Y. Intestinal microbiota-derived short-chain fatty acids regulation of immune cell IL-22 production and gut immunity. Nat Commun 2020; 11:4457. [PMID: 32901017 PMCID: PMC7478978 DOI: 10.1038/s41467-020-18262-6] [Citation(s) in RCA: 501] [Impact Index Per Article: 125.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 08/14/2020] [Indexed: 12/16/2022] Open
Abstract
Innate lymphoid cells (ILCs) and CD4+ T cells produce IL-22, which is critical for intestinal immunity. The microbiota is central to IL-22 production in the intestines; however, the factors that regulate IL-22 production by CD4+ T cells and ILCs are not clear. Here, we show that microbiota-derived short-chain fatty acids (SCFAs) promote IL-22 production by CD4+ T cells and ILCs through G-protein receptor 41 (GPR41) and inhibiting histone deacetylase (HDAC). SCFAs upregulate IL-22 production by promoting aryl hydrocarbon receptor (AhR) and hypoxia-inducible factor 1α (HIF1α) expression, which are differentially regulated by mTOR and Stat3. HIF1α binds directly to the Il22 promoter, and SCFAs increase HIF1α binding to the Il22 promoter through histone modification. SCFA supplementation enhances IL-22 production, which protects intestines from inflammation. SCFAs promote human CD4+ T cell IL-22 production. These findings establish the roles of SCFAs in inducing IL-22 production in CD4+ T cells and ILCs to maintain intestinal homeostasis.
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MESH Headings
- Animals
- Butyrates/immunology
- Butyrates/metabolism
- Butyrates/pharmacology
- CD4-Positive T-Lymphocytes/drug effects
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/microbiology
- Citrobacter rodentium
- Colitis/immunology
- Colitis/microbiology
- Colitis/prevention & control
- Enterobacteriaceae Infections/immunology
- Enterobacteriaceae Infections/microbiology
- Enterobacteriaceae Infections/prevention & control
- Fatty Acids, Volatile/immunology
- Fatty Acids, Volatile/metabolism
- Fatty Acids, Volatile/pharmacology
- Gastrointestinal Microbiome/immunology
- Gastrointestinal Microbiome/physiology
- Histone Deacetylase Inhibitors/pharmacology
- Humans
- Hypoxia-Inducible Factor 1, alpha Subunit/metabolism
- Immunity, Innate
- In Vitro Techniques
- Interleukins/biosynthesis
- Interleukins/deficiency
- Interleukins/genetics
- Lymphocytes/drug effects
- Lymphocytes/immunology
- Lymphocytes/microbiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Promoter Regions, Genetic
- Receptors, Aryl Hydrocarbon/metabolism
- Receptors, G-Protein-Coupled/metabolism
- Interleukin-22
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Affiliation(s)
- Wenjing Yang
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Tianming Yu
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, 77555, USA
- Department of Gastroenterology, The Shanghai Tenth People's Hospital, 200072, Shanghai, China
| | - Xiangsheng Huang
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Anthony J Bilotta
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Leiqi Xu
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Yao Lu
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Jiaren Sun
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Fan Pan
- Immunology and Hematopoiesis Division, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Jia Zhou
- Chemical Biology Program, Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Wenbo Zhang
- Department of Ophthalmology and Visual Sciences, The University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Suxia Yao
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Craig L Maynard
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Nagendra Singh
- Department of Biochemistry and Molecular Biology, Georgia Cancer Center, Augusta University, Augusta, GA, 30912, USA
| | - Sara M Dann
- Department of Internal Medicine, The University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Zhanju Liu
- Department of Gastroenterology, The Shanghai Tenth People's Hospital, 200072, Shanghai, China
| | - Yingzi Cong
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, 77555, USA.
- Department of Pathology, The University of Texas Medical Branch, Galveston, TX, 77555, USA.
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15
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Slater SL, Frankel G. Advances and Challenges in Studying Type III Secretion Effectors of Attaching and Effacing Pathogens. Front Cell Infect Microbiol 2020; 10:337. [PMID: 32733819 PMCID: PMC7358347 DOI: 10.3389/fcimb.2020.00337] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/04/2020] [Indexed: 12/24/2022] Open
Affiliation(s)
- Sabrina L Slater
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Gad Frankel
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
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16
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Hu X, Wang M, Pan Y, Xie Y, Han J, Zhang X, Niayale R, He H, Li Q, Zhao T, Cui Y, Yu S. Anti-inflammatory Effect of Astragalin and Chlorogenic Acid on Escherichia coli-Induced Inflammation of Sheep Endometrial Epithelium Cells. Front Vet Sci 2020; 7:201. [PMID: 32426380 PMCID: PMC7205036 DOI: 10.3389/fvets.2020.00201] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/26/2020] [Indexed: 12/13/2022] Open
Abstract
Endometritis is one of the main diseases which harm sheep husbandry. Astragalin and chlorogenic acid (CGA) are common active ingredients of traditional Chinese medicine (TCM) with immunoprotective, antioxidant, and anti-inflammatory properties. In the present study, sheep endometrial epithelium cells (SEECs) were successfully purified and identified, and the in vitro inflammation model of SEECs induced by Escherichia coli (E. coli) was successfully established. To explore the effect of astragalin and CGA on the inflammation induced by E. coli and its potential mechanism, six groups were set up, namely, group C, M, astragalin, CGA, BAY, and STR. Cells in group C were incubated with DMEM/F12 for 6 h, while cells in group M, astragalin, CGA, BAY, and STR were incubated with DMEM/F12, astragalin, CGA, BAY, and STR for 3 h, respectively, followed by E. coli infection at a multiplicity of infection (MOI) of 1 E. coli per cell for 3 h. Subsequently, the cells and the supernatant were collected to detect the expression of genes in the toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) pathway by ELISA, qPCR, and western blot. The results showed that E. coli could induce inflammation of SEECs in vitro, while astragalin and CGA could alleviate the inflammatory response induced by E. coli via inhibiting the activation of the TLR4/NF-κB signaling pathway, which provides a theoretical and experimental foundation for preventing sheep endometritis clinically.
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Affiliation(s)
- Xuequan Hu
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Meng Wang
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Yangyang Pan
- Technology and Research Center of Gansu Province for Embryonic Engineering of Bovine and Sheep & Goat, Lanzhou, China
| | - Yingying Xie
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Jinhui Han
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Xingyun Zhang
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Robert Niayale
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Honghong He
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Qin Li
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Tian Zhao
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Yan Cui
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Sijiu Yu
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
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17
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Wałecka-Zacharska E, Korkus J, Skowron K, Wietlicka-Piszcz M, Kosek-Paszkowska K, Bania J. Effect of Temperatures Used in Food Storage on Duration of Heat Stress Induced Invasiveness of L. monocytogenes. Microorganisms 2019; 7:E467. [PMID: 31627472 PMCID: PMC6843778 DOI: 10.3390/microorganisms7100467] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/31/2019] [Accepted: 10/17/2019] [Indexed: 12/02/2022] Open
Abstract
The unpropitious conditions of the food processing environmenttrigger in Listeria monocytogenes stress response mechanisms that may affect the pathogen's virulence. To date, many studies have revealed that acid, osmotic, heat, cold and oxidative stress modify invasiveness of L. monocytogenes. Nonetheless, there is limited data on the duration of the stress effect on bacterial invasiveness. Since most food is stored at low or room temperatures we studied the impact of these temperatures on the duration of heat stress effect on invasiveness of 8 L. monocytogenes strains. Bacteria were heat-treated for 20 min at 54 °C and then incubated at 5 and 20 °C up to 14 days. A decrease in invasiveness over time was observed for bacteria not exposed to heating. It was found that heat shock significantly reduced the invasion capacity of all strains and the effect lasted between 7 and 14 days at both 5 and 20 °C. In conclusion, 20-min heating reduces invasion capacity of all L. monocytogenes strains; however, the stress effect is temporary and lasts between 7 and 14 days in the food storage conditions. The invasiveness of bacteria changes along with the incubation time and is temperature-dependent.
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Affiliation(s)
- Ewa Wałecka-Zacharska
- Department of Food Hygiene and Consumer Health Protection, Wrocław University of Environmental and Life Sciences, 50-375 Wrocław, Poland; (J.K.); (K.K.-P.); (J.B.)
| | - Jakub Korkus
- Department of Food Hygiene and Consumer Health Protection, Wrocław University of Environmental and Life Sciences, 50-375 Wrocław, Poland; (J.K.); (K.K.-P.); (J.B.)
| | - Krzysztof Skowron
- Department of Microbiology, Nicolaus Copernicus University in Toruń, Collegium Medicum of L. Rydygier in Bydgoszcz, 85-094 Bydgoszcz, Poland;
| | - Magdalena Wietlicka-Piszcz
- Department of Theoretical Foundations of Biomedical Sciences and Medical Computer Science, Nicolaus Copernicus University in Toruń, L. Rydygier Collegium Medicum in Bydgoszcz, 9 M. Skłodowska-Curie St., 85-094 Bydgoszcz, Poland;
| | - Katarzyna Kosek-Paszkowska
- Department of Food Hygiene and Consumer Health Protection, Wrocław University of Environmental and Life Sciences, 50-375 Wrocław, Poland; (J.K.); (K.K.-P.); (J.B.)
| | - Jacek Bania
- Department of Food Hygiene and Consumer Health Protection, Wrocław University of Environmental and Life Sciences, 50-375 Wrocław, Poland; (J.K.); (K.K.-P.); (J.B.)
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18
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Lin R, Piao M, Song Y. Dietary Quercetin Increases Colonic Microbial Diversity and Attenuates Colitis Severity in Citrobacter rodentium-Infected Mice. Front Microbiol 2019; 10:1092. [PMID: 31156598 PMCID: PMC6531918 DOI: 10.3389/fmicb.2019.01092] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 04/30/2019] [Indexed: 12/13/2022] Open
Abstract
Disturbed balance between microbiota, epithelial cells, and resident immune cells within the intestine contributes to inflammatory bowel disease (IBD) pathogenesis. The Citrobacter rodentium-induced colitis mouse model has been well documented. This model allows the analysis of host responses to enteric bacteria and facilitates improved understanding of the potential mechanisms of IBD pathogenesis. The current study evaluated the effects of dietary 30 mg/kg quercetin supplementation on C. rodentium-induced experimental colitis in C57BL/6 mice. Following dietary quercetin supplementation, the mice were infected with 5 × 108 CFU C. rodentium, and the pathological effects of C. rodentium were measured. The results showed that quercetin alleviated the effects of C. rodentium-induced colitis, suppressed the production of pro-inflammatory cytokines, such as interleukin (IL)-17, tumor necrosis factor alpha, and IL-6 (p < 0.05), and promoted the production of IL-10 in the colon tissues (p < 0.05). Quercetin supplementation also enhanced the populations of Bacteroides, Bifidobacterium, Lactobacillus, and Clostridia and significantly reduced those of Fusobacterium and Enterococcus (p < 0.05). These findings indicate that dietary quercetin exerts therapeutic effects on C. rodentium-induced colitis, probably due to quercetin’s ability to suppress pro-inflammatory cytokines and/or modify gut microbiota. Thus, these results suggest that quercetin supplementation is effective in controlling C. rodentium-induced inflammation.
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Affiliation(s)
- Rui Lin
- Department of Gastroenterology and Hepatology, General Hospital, Tianjin Medical University, Tianjin, China
| | - Meiyu Piao
- Department of Gastroenterology and Hepatology, General Hospital, Tianjin Medical University, Tianjin, China
| | - Yan Song
- Department of Gastroenterology and Hepatology, General Hospital, Tianjin Medical University, Tianjin, China
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19
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Sun Y, Reid B, Ferreira F, Luxardi G, Ma L, Lokken KL, Zhu K, Xu G, Sun Y, Ryzhuk V, Guo BP, Lebrilla CB, Maverakis E, Mogilner A, Zhao M. Infection-generated electric field in gut epithelium drives bidirectional migration of macrophages. PLoS Biol 2019; 17:e3000044. [PMID: 30964858 PMCID: PMC6456179 DOI: 10.1371/journal.pbio.3000044] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 03/05/2019] [Indexed: 12/13/2022] Open
Abstract
Many bacterial pathogens hijack macrophages to egress from the port of entry to the lymphatic drainage and/or bloodstream, causing dissemination of life-threatening infections. However, the underlying mechanisms are not well understood. Here, we report that Salmonella infection generates directional electric fields (EFs) in the follicle-associated epithelium of mouse cecum. In vitro application of an EF, mimicking the infection-generated electric field (IGEF), induces directional migration of primary mouse macrophages to the anode, which is reversed to the cathode upon Salmonella infection. This infection-dependent directional switch is independent of the Salmonella pathogenicity island 1 (SPI-1) type III secretion system. The switch is accompanied by a reduction of sialic acids on glycosylated surface components during phagocytosis of bacteria, which is absent in macrophages challenged by microspheres. Moreover, enzymatic cleavage of terminally exposed sialic acids reduces macrophage surface negativity and severely impairs directional migration of macrophages in response to an EF. Based on these findings, we propose that macrophages are attracted to the site of infection by a combination of chemotaxis and galvanotaxis; after phagocytosis of bacteria, surface electrical properties of the macrophage change, and galvanotaxis directs the cells away from the site of infection.
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Affiliation(s)
- Yaohui Sun
- Department of Dermatology, School of Medicine, University of California, Davis, Sacramento, California, United States of America
- Courant Institute and Department of Biology, New York University, New York, New York, United States of America
| | - Brian Reid
- Department of Dermatology, School of Medicine, University of California, Davis, Sacramento, California, United States of America
| | - Fernando Ferreira
- Department of Dermatology, School of Medicine, University of California, Davis, Sacramento, California, United States of America
- Departamento de Biologia, Centro de Biologia Molecular e Ambiental (CBMA), Universidade do Minho, Braga, Portugal
| | - Guillaume Luxardi
- Department of Dermatology, School of Medicine, University of California, Davis, Sacramento, California, United States of America
| | - Li Ma
- Department of Dermatology, School of Medicine, University of California, Davis, Sacramento, California, United States of America
- Skin and Cosmetic Research Department, Shanghai Skin Disease Hospital, Shanghai, China
| | - Kristen L. Lokken
- Department of Microbiology and Immunology, School of Medicine, University of California, Davis, Davis, California, United States of America
| | - Kan Zhu
- Department of Dermatology, School of Medicine, University of California, Davis, Sacramento, California, United States of America
| | - Gege Xu
- Department of Chemistry, University of California, Davis, Davis, California, United States of America
| | - Yuxin Sun
- Department of Dermatology, School of Medicine, University of California, Davis, Sacramento, California, United States of America
| | - Volodymyr Ryzhuk
- Department of Dermatology, School of Medicine, University of California, Davis, Sacramento, California, United States of America
| | - Betty P. Guo
- Office of Research, School of Medicine, University of California, Davis, Davis, California, United States of America
| | - Carlito B. Lebrilla
- Department of Chemistry, University of California, Davis, Davis, California, United States of America
| | - Emanual Maverakis
- Department of Dermatology, School of Medicine, University of California, Davis, Sacramento, California, United States of America
| | - Alex Mogilner
- Courant Institute and Department of Biology, New York University, New York, New York, United States of America
| | - Min Zhao
- Department of Dermatology, School of Medicine, University of California, Davis, Sacramento, California, United States of America
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20
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Caballero-Flores G, Sakamoto K, Zeng MY, Wang Y, Hakim J, Matus-Acuña V, Inohara N, Núñez G. Maternal Immunization Confers Protection to the Offspring against an Attaching and Effacing Pathogen through Delivery of IgG in Breast Milk. Cell Host Microbe 2019; 25:313-323.e4. [PMID: 30686564 DOI: 10.1016/j.chom.2018.12.015] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 11/02/2018] [Accepted: 12/19/2018] [Indexed: 12/15/2022]
Abstract
Owing to immature immune systems and impaired colonization resistance mediated by the microbiota, infants are more susceptible to enteric infections. Maternal antibodies can provide immunity, with maternal vaccination offering a protective strategy. We find that oral infection of adult females with the enteric pathogen Citrobacter rodentium protects dams and offspring against oral challenge. Parenteral immunization of dams with heat-inactivated C. rodentium reduces pathogen loads and mortality in offspring but not mothers. IgG, but not IgA or IgM, transferred through breast milk to the intestinal lumen of suckling offspring, coats the pathogen and reduces intestinal colonization. Protective IgG largely recognizes virulence factors encoded within the locus of enterocyte effacement (LEE) pathogenicity island, including the adhesin Intimin and T3SS filament EspA, which are major antigens conferring protection. Thus, pathogen-specific IgG in breast milk induced during maternal infection or immunization protects neonates against infection with an attaching and effacing pathogen.
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Affiliation(s)
- Gustavo Caballero-Flores
- Department of Pathology and Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Kei Sakamoto
- Department of Pathology and Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Melody Y Zeng
- Department of Pathology and Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Yaqiu Wang
- Department of Pathology and Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Tsukuba 305-0006, Japan
| | - Jill Hakim
- Department of Pathology and Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Violeta Matus-Acuña
- Programa de Ecología Genómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, Mexico; School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI 48109, USA
| | - Naohiro Inohara
- Department of Pathology and Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Gabriel Núñez
- Department of Pathology and Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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21
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Acid-happy: Survival and recovery of enteropathogenic Escherichia coli (EPEC) in simulated gastric fluid. Microb Pathog 2019; 128:396-404. [PMID: 30660737 DOI: 10.1016/j.micpath.2019.01.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 12/14/2018] [Accepted: 01/16/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND Gastric fluid pH serves an important function as an ecological filter to kill unwanted microbial taxa that would otherwise colonise the intestines, thereby shaping the diversity and composition of microbial communities found in the gut. The typical American-based diet causes the gastric pH to increase to pH 4 to 5, and it takes ∼2 h to return to pH 1.5 (normal). This window of increased gastric pH may allow potential pathogens to negotiate the hostile environment of the stomach. Another factor to consider is that in developing countries many people experience hypochlorhydria related to malnutrition and various gastric diseases. Enteropathogenic E. coli (EPEC) is a leading cause of infantile diarrhoea and has a high incidence in the developing world. The aim of this study was to assess the survival and recovery of non-acid adapted EPEC exposed to simulated gastric fluid (SGF) over a period of 180 min. RESULTS EPEC were grown in nutrient-rich medium and acid challenged in SGF at pH 1.5, 2.5, 3.5 and 4.5. Culturability was evaluated using a standard plate count method, and metabolic viability was assessed via cellular energy (adenosine triphosphate [ATP] assay) and respiratory activity (3-bis(2-methyloxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide [XTT] assay), and recovery and proliferation by means of optical density in liquid cultures. Sampling was performed at 0, 30, 60, 120, and 180 min post-SGF exposure. The results of this study showed that EPEC is remarkably acid resistant and was able to survive a simulated gastric environment for up to 3 h (180 min) at various pH (1.5, 2.5, 3.5, and 4.5). EPEC was culturable at all pH (1.5, 2.5, 3.5 and 4.5) at the higher inoculum size of 5.4-7.1 × 106 CFU/ml, and at all pH except pH 1.5 at the lower inoculums of 5.4-7.1 × 103 CFU/ml or 5.4-7.1 × 101 CFU/ml. The organism remained metabolically viable at pH 1.5, 2.5, 3.5, and 4.5 and was able to recover and proliferate once placed in a neutral, nutrient-rich environment. CONCLUSION In this study, EPEC demonstrated remarkable acid resistance and recovery at low pH without prior acid adaptation, which could prove to be problematic even in healthy people. In individuals with decreased gastric acidity, there is a higher probability of pathogen colonization and a resulting change in the gut microbiome. The results highlight the potential increase of food- and waterborne diseases in persons with compromised gastric function, or who are malnourished or immunocompromised. The data herein may possibly help in calculating more precisely the risk associated with consuming bacterial contaminated food and water in these individuals.
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22
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Modeling Host-Pathogen Interactions in the Context of the Microenvironment: Three-Dimensional Cell Culture Comes of Age. Infect Immun 2018; 86:IAI.00282-18. [PMID: 30181350 DOI: 10.1128/iai.00282-18] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Tissues and organs provide the structural and biochemical landscapes upon which microbial pathogens and commensals function to regulate health and disease. While flat two-dimensional (2-D) monolayers composed of a single cell type have provided important insight into understanding host-pathogen interactions and infectious disease mechanisms, these reductionist models lack many essential features present in the native host microenvironment that are known to regulate infection, including three-dimensional (3-D) architecture, multicellular complexity, commensal microbiota, gas exchange and nutrient gradients, and physiologically relevant biomechanical forces (e.g., fluid shear, stretch, compression). A major challenge in tissue engineering for infectious disease research is recreating this dynamic 3-D microenvironment (biological, chemical, and physical/mechanical) to more accurately model the initiation and progression of host-pathogen interactions in the laboratory. Here we review selected 3-D models of human intestinal mucosa, which represent a major portal of entry for infectious pathogens and an important niche for commensal microbiota. We highlight seminal studies that have used these models to interrogate host-pathogen interactions and infectious disease mechanisms, and we present this literature in the appropriate historical context. Models discussed include 3-D organotypic cultures engineered in the rotating wall vessel (RWV) bioreactor, extracellular matrix (ECM)-embedded/organoid models, and organ-on-a-chip (OAC) models. Collectively, these technologies provide a more physiologically relevant and predictive framework for investigating infectious disease mechanisms and antimicrobial therapies at the intersection of the host, microbe, and their local microenvironments.
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Vahedi A, Soltan Dallal MM, Douraghi M, Nikkhahi F, Rajabi Z, Yousefi M, Mousavi M. Isolation and identification of specific bacteriophage against enteropathogenic Escherichia coli (EPEC) and in vitro and in vivo characterization of bacteriophage. FEMS Microbiol Lett 2018; 365:5044543. [DOI: 10.1093/femsle/fny136] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/31/2018] [Indexed: 12/22/2022] Open
Affiliation(s)
- Azadeh Vahedi
- School of Public Health, Tehran University of Medical Sciences, Ghods street, Tehran 3551713146, Iran
| | - Mohammad Mehdi Soltan Dallal
- Department of Microbiology and Pathobiology, Tehran University of Medical Sciences, Enghelab Sq., Tehran 1416753955, Iran
| | - Masoumeh Douraghi
- Department of Pathology, Tehran University of Medical Sciences, Poursina St., Tehran 14185781, Iran
| | - Farhad Nikkhahi
- Department of Medical Bacteriology–Pathobiology, Tehran University of Medical Sciences, District 6, Pour Sina St, Tehran 1416753955, Iran
| | - Zahra Rajabi
- Food Microbiology Research Center, Tehran University of Medical Sciences, Ghods st, Tehran 1416753955, Iran
| | - Maryam Yousefi
- Department of Virology, Tehran University of Medical Sciences, Ghods street, Tehran 1416753955, Iran
| | - Maryam Mousavi
- Department of Biostatistics, Faculty of medical sciences, Tarbiat Modares University, Tehran 3551713146, Iran
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Kang E, Crouse A, Chevallier L, Pontier SM, Alzahrani A, Silué N, Campbell-Valois FX, Montagutelli X, Gruenheid S, Malo D. Enterobacteria and host resistance to infection. Mamm Genome 2018; 29:558-576. [PMID: 29785663 DOI: 10.1007/s00335-018-9749-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 05/14/2018] [Indexed: 02/06/2023]
Abstract
Enterobacteriaceae are a large family of Gram-negative, non-spore-forming bacteria. Although many species exist as part of the natural flora of animals including humans, some members are associated with both intestinal and extraintestinal diseases. In this review, we focus on members of this family that have important roles in human disease: Salmonella, Escherichia, Shigella, and Yersinia, providing a brief overview of the disease caused by these bacteria, highlighting the contribution of animal models to our understanding of their pathogenesis and of host genetic determinants involved in susceptibility or resistance to infection.
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Affiliation(s)
- Eugene Kang
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
- McGill Research Center on Complex Traits, McGill University, Montreal, QC, Canada
| | - Alanna Crouse
- McGill Research Center on Complex Traits, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Lucie Chevallier
- U955 - IMRB, Team 10 - Biology of the neuromuscular system, Inserm, École Nationale Vétérinaire d'Alfort, UPEC, Maisons-Alfort, France
- Mouse Genetics Laboratory, Department of Genomes and Genetics, Institut Pasteur, Paris, France
| | - Stéphanie M Pontier
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, Ottawa, ON, Canada
| | - Ashwag Alzahrani
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, Ottawa, ON, Canada
| | - Navoun Silué
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, Ottawa, ON, Canada
| | - François-Xavier Campbell-Valois
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, Ottawa, ON, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Xavier Montagutelli
- U955 - IMRB, Team 10 - Biology of the neuromuscular system, Inserm, École Nationale Vétérinaire d'Alfort, UPEC, Maisons-Alfort, France
| | - Samantha Gruenheid
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
- McGill Research Center on Complex Traits, McGill University, Montreal, QC, Canada
| | - Danielle Malo
- McGill Research Center on Complex Traits, McGill University, Montreal, QC, Canada.
- Department of Human Genetics, McGill University, Montreal, QC, Canada.
- Department of Medicine, McGill University, Montreal, QC, Canada.
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25
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Kuo CJ, Wang ST, Chen CS. Detection of Enterohemorrhagic Escherichia Coli Colonization in Murine Host by Non-invasive In Vivo Bioluminescence System. J Vis Exp 2018. [PMID: 29683443 DOI: 10.3791/56169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Enterohemorrhagic E. coli (EHEC) O157:H7, which is a foodborne pathogen that causesdiarrhea, hemorrhagic colitis (HS), and hemolytic uremic syndrome (HUS), colonize to the intestinal tract of humans. To study the detailed mechanism of EHEC colonization in vivo, it is essential to have animal models to monitor and quantify EHEC colonization. We demonstrate here a mouse-EHEC colonization model by transforming the bioluminescent expressing plasmid to EHEC to monitor and quantify EHEC colonization in living hosts. Animals inoculated with bioluminescence-labeled EHEC show intense bioluminescent signals in mice by detection with a non-invasive in vivo imaging system. After 1 and 2 days post infection, bioluminescent signals could still be detected in infected animals, which suggests that EHEC colonize in hosts for at least 2 days. We also demonstrate that these bioluminescent EHEC locate to mouse intestine, specifically in the cecum and colon, from ex vivo images. This mouse-EHEC colonization model may serve as a tool to advance the current knowledge of the EHEC colonization mechanism.
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Affiliation(s)
- Cheng-Ju Kuo
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University; Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University
| | - Sin-Tian Wang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University; Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University
| | - Chang-Shi Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University; Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University;
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Roxas JL, Viswanathan VK. Modulation of Intestinal Paracellular Transport by Bacterial Pathogens. Compr Physiol 2018; 8:823-842. [PMID: 29687905 DOI: 10.1002/cphy.c170034] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The passive and regulated movement of ions, solutes, and water via spaces between cells of the epithelial monolayer plays a critical role in the normal intestinal functioning. This paracellular pathway displays a high level of structural and functional specialization, with the membrane-spanning complexes of the tight junctions, adherens junctions, and desmosomes ensuring its integrity. Tight junction proteins, like occludin, tricellulin, and the claudin family isoforms, play prominent roles as barriers to unrestricted paracellular transport. The past decade has witnessed major advances in our understanding of the architecture and function of epithelial tight junctions. While it has been long appreciated that microbes, notably bacterial and viral pathogens, target and disrupt junctional complexes and alter paracellular permeability, the precise mechanisms remain to be defined. Notably, renewed efforts will be required to interpret the available data on pathogen-mediated barrier disruption in the context of the most recent findings on tight junction structure and function. While much of the focus has been on pathogen-induced dysregulation of junctional complexes, commensal microbiota and their products may influence paracellular permeability and contribute to the normal physiology of the gut. Finally, microbes and their products have become important tools in exploring host systems, including the junctional properties of epithelial cells. © 2018 American Physiological Society. Compr Physiol 8:823-842, 2018.
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Affiliation(s)
- Jennifer Lising Roxas
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - V K Viswanathan
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA.,Department of Immunobiology, University of Arizona, Tucson, Arizona, USA.,BIO5 Institute for Collaborative Research, University of Arizona, Tucson, Arizona, USA
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Multitalented EspB of enteropathogenic Escherichia coli (EPEC) enters cells autonomously and induces programmed cell death in human monocytic THP-1 cells. Int J Med Microbiol 2018; 308:387-404. [PMID: 29550166 DOI: 10.1016/j.ijmm.2018.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/06/2018] [Accepted: 03/11/2018] [Indexed: 12/26/2022] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) subvert host cell signaling pathways by injecting effector proteins via a Type 3 Secretion System (T3SS). The T3SS-dependent EspB protein is a multi-functional effector protein, which contributes to adherence and translocator pore formation and after injection exhibits several intracellular activities. In addition, EspB is also secreted into the environment. Effects of secreted EspB have not been reported thus far. As a surrogate for secreted EspB we employed recombinant EspB (rEspB) derived from the prototype EPEC strain E2348/69 and investigated the interactions of the purified protein with different human epithelial and immune cells including monocytic THP-1 cells, macrophages, dendritic cells, U-937, epithelial T84, Caco-2, and HeLa cells. To assess whether these proteins might exert a cytotoxic effect we monitored the release of lactate dehydrogenase (LDH) as well as propidium iodide (PI) uptake. For comparison, we also investigated several homologs of EspB such as IpaD of Shigella, and SipC, SipD, SseB, and SseD of Salmonella as purified recombinant proteins. Interestingly, cytotoxicity was only observed in THP-1 cells and macrophages, whereas epithelial cells remained unaffected. Cell fractionation and immune fluorescence experiments showed that rEspB enters cells autonomously, which suggests that EspB might qualify as a novel cell-penetrating effector protein (CPE). Using specific organelle tracers and inhibitors of signaling pathways we found that rEspB destroys the mitochondrial membrane potential - an indication of programmed cell death induction in THP-1 cells. Here we show that EspB not only constitutes an essential part of the T3SS-nanomachine and contributes to the arsenal of injected effector proteins but, furthermore, that secreted (recombinant) EspB autonomously enters host cells and selectively induces cell death in immune cells.
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28
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Singh AP, Sharma S, Pagarware K, Siraji RA, Ansari I, Mandal A, Walling P, Aijaz S. Enteropathogenic E. coli effectors EspF and Map independently disrupt tight junctions through distinct mechanisms involving transcriptional and post-transcriptional regulation. Sci Rep 2018; 8:3719. [PMID: 29487356 PMCID: PMC5829253 DOI: 10.1038/s41598-018-22017-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 02/14/2018] [Indexed: 01/05/2023] Open
Abstract
Enteropathogenic E. coli infection is characterized by rapid onset of diarrhea but the underlying mechanisms are not well defined. EPEC targets the tight junctions which selectively regulate the permeability of charged and uncharged molecules. Cooperative actions of the EPEC effectors EspF and Map have been reported to mediate tight junction disruption. To analyze the individual contributions of EspF and Map, we generated in vitro models where EspF and Map, derived from the EPEC strain E2348/69, were constitutively expressed in epithelial cells. Here we report that tight junction disruption by EspF and Map is caused by the inhibition of the junctional recruitment of proteins during tight junction assembly. Constitutive expression of EspF and Map depleted the levels of tight junction proteins. EspF down-regulated the transcript levels of claudin-1, occludin and ZO-1, while Map down-regulated only claudin-1 transcripts. Both effectors also caused lysosomal degradation of existing tight junction proteins. We also identified a novel interaction of Map with non-muscle myosin II. Consistent with earlier studies, EspF was found to interact with ZO-1 while actin was the common interacting partner for both effectors. Our data provides evidence for the distinct roles of Map and EspF in tight junction disruption through non-synergistic functions.
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Affiliation(s)
- Anand Prakash Singh
- Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Swati Sharma
- Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Kirti Pagarware
- Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Rafay Anwar Siraji
- Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Imran Ansari
- Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Anupam Mandal
- Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Pangertoshi Walling
- Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Saima Aijaz
- Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India.
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29
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Type Three Secretion System-Dependent Microvascular Thrombosis and Ischemic Enteritis in Human Gut Xenografts Infected with Enteropathogenic Escherichia coli. Infect Immun 2017; 85:IAI.00558-17. [PMID: 28784929 DOI: 10.1128/iai.00558-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 08/04/2017] [Indexed: 01/01/2023] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) is a leading cause of severe intestinal disease and infant mortality in developing countries. Virulence is mediated by a type three secretion system (T3SS), causing the hallmark attaching and effacing (AE) lesions and actin-rich pedestal formation beneath the infecting bacteria on the apical surface of enterocytes. EPEC is a human-specific pathogen whose pathogenesis cannot be studied in animal models. We therefore established an EPEC infection model in human gut xenografts in SCID mice and used it to study the role of T3SS in the pathogenesis of the disease. Following EPEC O127:H6 strain E2348/69 infection, T3SS-dependent AE lesions and pedestals were demonstrated in all infected xenografts. We report here the development of T3SS-dependent intestinal thrombotic microangiopathy (iTMA) and ischemic enteritis in ∼50% of infected human gut xenografts. Using species-specific CD31 immunostaining, we showed that iTMA was limited to the larger human-mouse chimeric blood vessels, which are located between the muscularis mucosa and circular muscular layer of the human gut. These blood vessels were massively invaded by bacteria, which adhered to and formed pedestals on endothelial cells and aggregated with mouse neutrophils in the lumen. We conclude that endothelial infection, iTMA, and ischemic enteritis might be central mechanisms underlying severe EPEC-mediated disease.
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30
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Litvak Y, Sharon S, Hyams M, Zhang L, Kobi S, Katsowich N, Dishon S, Nussbaum G, Dong N, Shao F, Rosenshine I. Epithelial cells detect functional type III secretion system of enteropathogenic Escherichia coli through a novel NF-κB signaling pathway. PLoS Pathog 2017; 13:e1006472. [PMID: 28671993 PMCID: PMC5510907 DOI: 10.1371/journal.ppat.1006472] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 07/14/2017] [Accepted: 06/15/2017] [Indexed: 02/02/2023] Open
Abstract
Enteropathogenic Escherichia coli (EPEC), a common cause of infant diarrhea, is associated with high risk of mortality in developing countries. The primary niche of infecting EPEC is the apical surface of intestinal epithelial cells. EPEC employs a type three secretion system (TTSS) to inject the host cells with dozens of effector proteins, which facilitate attachment to these cells and successful colonization. Here we show that EPEC elicit strong NF-κB activation in infected host cells. Furthermore, the data indicate that active, pore-forming TTSS per se is necessary and sufficient for this NF-κB activation, regardless of any specific effector or protein translocation. Importantly, upon infection with wild type EPEC this NF-κB activation is antagonized by anti-NF-κB effectors, including NleB, NleC and NleE. Accordingly, this NF-κB activation is evident only in cells infected with EPEC mutants deleted of nleB, nleC, and nleE. The TTSS-dependent NF-κB activation involves a unique pathway, which is independent of TLRs and Nod1/2 and converges with other pathways at the level of TAK1 activation. Taken together, our results imply that epithelial cells have the capacity to sense the EPEC TTSS and activate NF-κB in response. Notably, EPEC antagonizes this capacity by delivering anti-NF-κB effectors into the infected cells.
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Affiliation(s)
- Yael Litvak
- Department of Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Shir Sharon
- Department of Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Meirav Hyams
- Department of Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Li Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; National Institute of Biological Sciences, Beijing, China
| | - Simi Kobi
- Department of Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Naama Katsowich
- Department of Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Shira Dishon
- The Institute of Dental Sciences, Hebrew University-Hadassah Faculty of Dental Medicine, Jerusalem, Israel
| | - Gabriel Nussbaum
- The Institute of Dental Sciences, Hebrew University-Hadassah Faculty of Dental Medicine, Jerusalem, Israel
| | - Na Dong
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; National Institute of Biological Sciences, Beijing, China
| | - Feng Shao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; National Institute of Biological Sciences, Beijing, China
| | - Ilan Rosenshine
- Department of Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
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31
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Waseem H, Williams MR, Stedtfeld T, Chai B, Stedtfeld RD, Cole JR, Tiedje JM, Hashsham SA. Virulence factor activity relationships (VFARs): a bioinformatics perspective. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2017; 19:247-260. [PMID: 28261716 PMCID: PMC5897045 DOI: 10.1039/c6em00689b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Virulence factor activity relationships (VFARs) - a concept loosely based on quantitative structure-activity relationships (QSARs) for chemicals was proposed as a predictive tool for ranking risks due to microorganisms relevant to water safety. A rapid increase in sequencing capabilities and bioinformatics tools has significantly increased the potential for VFAR-based analyses. This review summarizes more than 20 bioinformatics databases and tools, developed over the last decade, along with their virulence and antimicrobial resistance prediction capabilities. With the number of bacterial whole genome sequences exceeding 241 000 and metagenomic analysis projects exceeding 13 000 and the ability to add additional genome sequences for few hundred dollars, it is evident that further development of VFARs is not limited by the availability of information at least at the genomic level. However, additional information related to co-occurrence, treatment response, modulation of virulence due to environmental and other factors, and economic impact must be gathered and incorporated in a manner that also addresses the associated uncertainties. Of the bioinformatics tools, a majority are either designed exclusively for virulence/resistance determination or equipped with a dedicated module. The remaining have the potential to be employed for evaluating virulence. This review focusing broadly on omics technologies and tools supports the notion that these tools are now sufficiently developed to allow the application of VFAR approaches combined with additional engineering and economic analyses to rank and prioritize organisms important to a given niche. Knowledge gaps do exist but can be filled with focused experimental and theoretical analyses that were unimaginable a decade ago. Further developments should consider the integration of the measurement of activity, risk, and uncertainty to improve the current capabilities.
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Affiliation(s)
- Hassan Waseem
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA.
| | - Maggie R Williams
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA.
| | - Tiffany Stedtfeld
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA.
| | - Benli Chai
- Center for Microbial Ecology, Michigan State University, East Lansing, MI 48824, USA
| | - Robert D Stedtfeld
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA.
| | - James R Cole
- Center for Microbial Ecology, Michigan State University, East Lansing, MI 48824, USA
| | - James M Tiedje
- Center for Microbial Ecology, Michigan State University, East Lansing, MI 48824, USA and Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, USA
| | - Syed A Hashsham
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA. and Center for Microbial Ecology, Michigan State University, East Lansing, MI 48824, USA and Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, USA
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32
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Yu H, Hasan NM, In JG, Estes MK, Kovbasnjuk O, Zachos NC, Donowitz M. The Contributions of Human Mini-Intestines to the Study of Intestinal Physiology and Pathophysiology. Annu Rev Physiol 2017; 79:291-312. [PMID: 28192061 PMCID: PMC5549102 DOI: 10.1146/annurev-physiol-021115-105211] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The lack of accessibility to normal and diseased human intestine and the inability to separate the different functional compartments of the intestine even when tissue could be obtained have held back the understanding of human intestinal physiology. Clevers and his associates identified intestinal stem cells and established conditions to grow "mini-intestines" ex vivo in differentiated and undifferentiated conditions. This pioneering work has made a new model of the human intestine available and has begun making contributions to the understanding of human intestinal transport in normal physiologic conditions and the pathophysiology of intestinal diseases. However, this model is reductionist and lacks many of the complexities of normal intestine. Consequently, it is not yet possible to predict how great the advances using this model will be for understanding human physiology and pathophysiology, nor how the model will be modified to include multiple other intestinal cell types and physical forces necessary to more closely approximate normal intestine. This review describes recent studies using mini-intestines, which have readdressed previously established models of normal intestinal transport physiology and newly examined intestinal pathophysiology. The emphasis is on studies with human enteroids grown either as three-dimensional spheroids or two-dimensional monolayers. In addition, comments are provided on mouse studies in cases when human studies have not yet been described.
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Affiliation(s)
- Huimin Yu
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
| | - Nesrin M Hasan
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
| | - Julie G In
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
| | - Mary K Estes
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030
| | - Olga Kovbasnjuk
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
| | - Nicholas C Zachos
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
| | - Mark Donowitz
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
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Escherichia albertii, a novel human enteropathogen, colonizes rat enterocytes and translocates to extra-intestinal sites. PLoS One 2017; 12:e0171385. [PMID: 28178312 PMCID: PMC5298312 DOI: 10.1371/journal.pone.0171385] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 01/18/2017] [Indexed: 01/01/2023] Open
Abstract
Diarrhea is the second leading cause of death of children up to five years old in the developing countries. Among the etiological diarrheal agents are atypical enteropathogenic Escherichia coli (aEPEC), one of the diarrheagenic E. coli pathotypes that affects children and adults, even in developed countries. Currently, genotypic and biochemical approaches have helped to demonstrate that some strains classified as aEPEC are actually E. albertii, a recently recognized human enteropathogen. Studies on particular strains are necessary to explore their virulence potential in order to further understand the underlying mechanisms of E. albertii infections. Here we demonstrated for the first time that infection of fragments of rat intestinal mucosa is a useful tool to study the initial steps of E. albertii colonization. We also observed that an E. albertii strain can translocate from the intestinal lumen to Mesenteric Lymph Nodes and liver in a rat model. Based on our finding of bacterial translocation, we investigated how E. albertii might cross the intestinal epithelium by performing infections of M-like cells in vitro to identify the potential in vivo translocation route. Altogether, our approaches allowed us to draft a general E. albertii infection route from the colonization till the bacterial spreading in vivo.
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Systematic Analysis of Two-Component Systems in Citrobacter rodentium Reveals Positive and Negative Roles in Virulence. Infect Immun 2017; 85:IAI.00654-16. [PMID: 27872242 DOI: 10.1128/iai.00654-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/13/2016] [Indexed: 02/07/2023] Open
Abstract
Citrobacter rodentium is a murine pathogen used to model intestinal infections caused by the human diarrheal pathogens enterohemorrhagic and enteropathogenic Escherichia coli During infection, bacteria use two-component systems (TCSs) to detect changing environmental cues within the host, allowing for rapid adaptation by altering the expression of specific genes. In this study, 26 TCSs were identified in C. rodentium, and quantitative PCR (qPCR) analysis showed that they are all expressed during murine infection. These TCSs were individually deleted, and the in vitro and in vivo effects were analyzed to determine the functional consequences. In vitro analyses only revealed minor differences, and surprisingly, type III secretion (T3S) was only affected in the ΔarcA strain. Murine infections identified 7 mutants with either attenuated or increased virulence. In agreement with the in vitro T3S assay, the ΔarcA strain was attenuated and defective in colonization and cell adherence. The ΔrcsB strain was among the most highly attenuated strains. The decrease in virulence of this strain may be associated with changes to the cell surface, as Congo red binding was altered, and qPCR revealed that expression of the wcaA gene, which has been implicated in colanic acid production in other bacteria, was drastically downregulated. The ΔuvrY strain exhibited increased virulence compared to the wild type, which was associated with a significant increase in bacterial burden within the mesenteric lymph nodes. The systematic analysis of virulence-associated TCSs and investigation of their functions during infection may open new avenues for drug development.
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Heinz E, Stubenrauch CJ, Grinter R, Croft NP, Purcell AW, Strugnell RA, Dougan G, Lithgow T. Conserved Features in the Structure, Mechanism, and Biogenesis of the Inverse Autotransporter Protein Family. Genome Biol Evol 2016; 8:1690-705. [PMID: 27190006 PMCID: PMC4943183 DOI: 10.1093/gbe/evw112] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The bacterial cell surface proteins intimin and invasin are virulence factors that share a common domain structure and bind selectively to host cell receptors in the course of bacterial pathogenesis. The β-barrel domains of intimin and invasin show significant sequence and structural similarities. Conversely, a variety of proteins with sometimes limited sequence similarity have also been annotated as “intimin-like” and “invasin” in genome datasets, while other recent work on apparently unrelated virulence-associated proteins ultimately revealed similarities to intimin and invasin. Here we characterize the sequence and structural relationships across this complex protein family. Surprisingly, intimins and invasins represent a very small minority of the sequence diversity in what has been previously the “intimin/invasin protein family”. Analysis of the assembly pathway for expression of the classic intimin, EaeA, and a characteristic example of the most prevalent members of the group, FdeC, revealed a dependence on the translocation and assembly module as a common feature for both these proteins. While the majority of the sequences in the grouping are most similar to FdeC, a further and widespread group is two-partner secretion systems that use the β-barrel domain as the delivery device for secretion of a variety of virulence factors. This comprehensive analysis supports the adoption of the “inverse autotransporter protein family” as the most accurate nomenclature for the family and, in turn, has important consequences for our overall understanding of the Type V secretion systems of bacterial pathogens.
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Affiliation(s)
- Eva Heinz
- Department of Microbiology, Infection & Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Christopher J Stubenrauch
- Department of Microbiology, Infection & Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Rhys Grinter
- Department of Microbiology, Infection & Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia Institute of Microbiology and Infection, School of Immunity and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Nathan P Croft
- Department of Biochemistry and Molecular Biology, Infection & Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Anthony W Purcell
- Department of Biochemistry and Molecular Biology, Infection & Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Richard A Strugnell
- Department of Microbiology & Immunology, University of Melbourne, Parkville, Australia
| | - Gordon Dougan
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Trevor Lithgow
- Department of Microbiology, Infection & Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
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DOCK2 confers immunity and intestinal colonization resistance to Citrobacter rodentium infection. Sci Rep 2016; 6:27814. [PMID: 27291827 PMCID: PMC4904218 DOI: 10.1038/srep27814] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 05/25/2016] [Indexed: 12/13/2022] Open
Abstract
Food poisoning is one of the leading causes of morbidity and mortality in the world. Citrobacter rodentium is an enteric pathogen which attaches itself to enterocytes and induces attachment and effacing (A/E) lesions. The ability of the bacterium to cause infection requires subversion of the host actin cytoskeleton. Rac-dependent actin polymerization is activated by a guanine nucleotide exchange factor known as Dedicator of cytokinesis 2 (DOCK2). However, the role of DOCK2 in infectious disease is largely unexplored. Here, we found that mice lacking DOCK2 were susceptible to C. rodentium infection. These mice harbored increased levels of C. rodentium bacteria, showed more pronounced weight loss and inflammation-associated pathology, and were prone to bacterial dissemination to the systemic organs compared with wild-type mice. We found that mice lacking DOCK2 were more susceptible to C. rodentium attachment to intestinal epithelial cells. Therefore, our results underscored an important role of DOCK2 for gastrointestinal immunity to C. rodentium infection.
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Li D, Chen Z, Cheng H, Zheng JX, Pan WG, Yang WZ, Yu ZJ, Deng QW. Inhibition of Adhesion of Enteropathogenic Escherichia coli to HEp-2 Cells by Binding of a Novel Peptide to EspB Protein. Curr Microbiol 2016; 73:361-365. [PMID: 27246497 DOI: 10.1007/s00284-016-1070-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 04/23/2016] [Indexed: 12/21/2022]
Abstract
Enteropathogenic Escherichia coli (EPEC) is a major cause of infantile diarrhea in developing countries. The translocator EspB is a key virulence factor in the process of the attaching and effacing effect of EPEC and plays a critical role in the pathogenesis of the bacteria. In this study, we aimed to select the peptides binding to EspB protein by phage display library and further investigate whether these peptides can decrease the extent of invasion and virulence of EPEC on host cells by targeting to EspB protein. The expression and purification of EspB protein from E. coli was demonstrated by Western blotting. The Ph.D. 12-mer peptide phage display library was used to screen the candidate peptides binding specifically to EspB protein. Furthermore, the affinity of these candidate peptides bound to EspB was identified by enzyme-linked immunosorbent assay (ELISA). Moreover, we investigated whether these screened peptides could decrease the adherence ratio of EPEC to HEp-2 cells with increasing concentration. Successful purification of EspB protein from pET21b-EspB-transformed E. coli was identified by Western blotting. Then, the candidate peptides including phages 6, 7, 8, and 12 were screened by the Ph.D. 12-mer peptide phage display library and ELISA test demonstrated that their affinity binding to EspB protein was high compared with the control. Functional analysis indicated that synthetic peptide-6 (YFPYSHTSPRQP) significantly decreased the adherence ratio of EPEC to HEp-2 cells with increasing concentration (P < 0.01). Peptide-6 (100 µg/mL) could lead to a 40 % decrease in the adherence ratio of EPEC to HEp-2 cells compared with control (P < 0.01). However, the other three peptides at different concentrations showed only a slight ability to block the adherence of EPEC to host cells. Our data provided a potential strategy to inhibit the adhesion of EPEC to epithelial cells by a candidate peptide targeted toward EspB protein.
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Affiliation(s)
- Duoyun Li
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, The Affiliated Shenzhen Nanshan Hospital, Guangdong Medical College, No 89 Taoyuan Road, Nanshan District, Shenzhen, 518052, China
| | - Zhong Chen
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, The Affiliated Shenzhen Nanshan Hospital, Guangdong Medical College, No 89 Taoyuan Road, Nanshan District, Shenzhen, 518052, China
| | - Hang Cheng
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, The Affiliated Shenzhen Nanshan Hospital, Guangdong Medical College, No 89 Taoyuan Road, Nanshan District, Shenzhen, 518052, China
| | - Jin-Xin Zheng
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, The Affiliated Shenzhen Nanshan Hospital, Guangdong Medical College, No 89 Taoyuan Road, Nanshan District, Shenzhen, 518052, China
| | - Wei-Guang Pan
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, The Affiliated Shenzhen Nanshan Hospital, Guangdong Medical College, No 89 Taoyuan Road, Nanshan District, Shenzhen, 518052, China
| | - Wei-Zhi Yang
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, The Affiliated Shenzhen Nanshan Hospital, Guangdong Medical College, No 89 Taoyuan Road, Nanshan District, Shenzhen, 518052, China
| | - Zhi-Jian Yu
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, The Affiliated Shenzhen Nanshan Hospital, Guangdong Medical College, No 89 Taoyuan Road, Nanshan District, Shenzhen, 518052, China.
| | - Qi-Wen Deng
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, The Affiliated Shenzhen Nanshan Hospital, Guangdong Medical College, No 89 Taoyuan Road, Nanshan District, Shenzhen, 518052, China.
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Dupont A, Sommer F, Zhang K, Repnik U, Basic M, Bleich A, Kühnel M, Bäckhed F, Litvak Y, Fulde M, Rosenshine I, Hornef MW. Age-Dependent Susceptibility to Enteropathogenic Escherichia coli (EPEC) Infection in Mice. PLoS Pathog 2016; 12:e1005616. [PMID: 27159323 PMCID: PMC4861285 DOI: 10.1371/journal.ppat.1005616] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 04/15/2016] [Indexed: 01/14/2023] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) represents a major causative agent of infant diarrhea associated with significant morbidity and mortality in developing countries. Although studied extensively in vitro, the investigation of the host-pathogen interaction in vivo has been hampered by the lack of a suitable small animal model. Using RT-PCR and global transcriptome analysis, high throughput 16S rDNA sequencing as well as immunofluorescence and electron microscopy, we characterize the EPEC-host interaction following oral challenge of newborn mice. Spontaneous colonization of the small intestine and colon of neonate mice that lasted until weaning was observed. Intimate attachment to the epithelial plasma membrane and microcolony formation were visualized only in the presence of a functional bundle forming pili (BFP) and type III secretion system (T3SS). Similarly, a T3SS-dependent EPEC-induced innate immune response, mediated via MyD88, TLR5 and TLR9 led to the induction of a distinct set of genes in infected intestinal epithelial cells. Infection-induced alterations of the microbiota composition remained restricted to the postnatal period. Although EPEC colonized the adult intestine in the absence of a competing microbiota, no microcolonies were observed at the small intestinal epithelium. Here, we introduce the first suitable mouse infection model and describe an age-dependent, virulence factor-dependent attachment of EPEC to enterocytes in vivo.
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Affiliation(s)
- Aline Dupont
- Institute for Medical Microbiology, RWTH Aachen University Hospital, Aachen, Germany
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
- * E-mail: (AD); (MWH)
| | - Felix Sommer
- The Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Kaiyi Zhang
- Institute for Medical Microbiology, RWTH Aachen University Hospital, Aachen, Germany
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Urska Repnik
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Marijana Basic
- Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - André Bleich
- Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - Mark Kühnel
- Institute for Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Fredrik Bäckhed
- The Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Yael Litvak
- Department for Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Marcus Fulde
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Ilan Rosenshine
- Department for Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mathias W. Hornef
- Institute for Medical Microbiology, RWTH Aachen University Hospital, Aachen, Germany
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
- * E-mail: (AD); (MWH)
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Anti-infective activities of lactobacillus strains in the human intestinal microbiota: from probiotics to gastrointestinal anti-infectious biotherapeutic agents. Clin Microbiol Rev 2016; 27:167-99. [PMID: 24696432 DOI: 10.1128/cmr.00080-13] [Citation(s) in RCA: 206] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A vast and diverse array of microbial species displaying great phylogenic, genomic, and metabolic diversity have colonized the gastrointestinal tract. Resident microbes play a beneficial role by regulating the intestinal immune system, stimulating the maturation of host tissues, and playing a variety of roles in nutrition and in host resistance to gastric and enteric bacterial pathogens. The mechanisms by which the resident microbial species combat gastrointestinal pathogens are complex and include competitive metabolic interactions and the production of antimicrobial molecules. The human intestinal microbiota is a source from which Lactobacillus probiotic strains have often been isolated. Only six probiotic Lactobacillus strains isolated from human intestinal microbiota, i.e., L. rhamnosus GG, L. casei Shirota YIT9029, L. casei DN-114 001, L. johnsonii NCC 533, L. acidophilus LB, and L. reuteri DSM 17938, have been well characterized with regard to their potential antimicrobial effects against the major gastric and enteric bacterial pathogens and rotavirus. In this review, we describe the current knowledge concerning the experimental antibacterial activities, including antibiotic-like and cell-regulating activities, and therapeutic effects demonstrated in well-conducted, placebo-controlled, randomized clinical trials of these probiotic Lactobacillus strains. What is known about the antimicrobial activities supported by the molecules secreted by such probiotic Lactobacillus strains suggests that they constitute a promising new source for the development of innovative anti-infectious agents that act luminally and intracellularly in the gastrointestinal tract.
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Singh AP, Aijaz S. Generation of a MDCK cell line with constitutive expression of the Enteropathogenic E. coli effector protein Map as an in vitro model of pathogenesis. Bioengineered 2015; 6:335-41. [PMID: 26430918 DOI: 10.1080/21655979.2015.1096456] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Enteropathogenic E. coli (EPEC) cause diarrhea and are the major cause of mortality in developing countries. EPEC use a type III secretion system to deliver effector proteins into the host epithelial cells. To understand the functions of these effectors, majority of studies on EPEC pathogenesis have relied on infections of animals or cell lines with wild type strains of EPEC or mutant strains deficient in one or more effectors. While these studies have provided valuable data, it can be difficult to assess functions of an individual effector in the presence of other EPEC effectors. Recent studies have reported the use of transient transfections with plasmids encoding various EPEC effectors into different cell lines. However, variable transfection efficiencies and expression levels of the effector proteins coupled with their expression for relatively short periods of time pose a problem if the long term effects of these effectors need to be examined. We have generated a MDCK cell line with constitutive expression of the EPEC effector Map (Mitochondrial associated protein) for efficient stable expression of EGFP-tagged Map. We observed that the constitutive expression of Map increased the permeability of charged and non-charged molecules. We also generated polyclonal antibodies against Map and checked for their specificity in MDCK-Map expressing cells. Map has been reported to contribute to the onset of diarrhea but the underlying mechanism is yet to be identified. The MDCK-Map cell line and the anti-Map antibodies generated by us can be used for in vitro studies to examine the role of Map in EPEC pathogenesis.
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Affiliation(s)
- Anand Prakash Singh
- a Centre for Molecular Medicine; Jawaharlal Nehru University ; New Delhi, India
| | - Saima Aijaz
- a Centre for Molecular Medicine; Jawaharlal Nehru University ; New Delhi, India
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Pathogenesis of human diffusely adhering Escherichia coli expressing Afa/Dr adhesins (Afa/Dr DAEC): current insights and future challenges. Clin Microbiol Rev 2015; 27:823-69. [PMID: 25278576 DOI: 10.1128/cmr.00036-14] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The pathogenicity and clinical pertinence of diffusely adhering Escherichia coli expressing the Afa/Dr adhesins (Afa/Dr DAEC) in urinary tract infections (UTIs) and pregnancy complications are well established. In contrast, the implication of intestinal Afa/Dr DAEC in diarrhea is still under debate. These strains are age dependently involved in diarrhea in children, are apparently not involved in diarrhea in adults, and can also be asymptomatic intestinal microbiota strains in children and adult. This comprehensive review analyzes the epidemiology and diagnosis and highlights recent progress which has improved the understanding of Afa/Dr DAEC pathogenesis. Here, I summarize the roles of Afa/Dr DAEC virulence factors, including Afa/Dr adhesins, flagella, Sat toxin, and pks island products, in the development of specific mechanisms of pathogenicity. In intestinal epithelial polarized cells, the Afa/Dr adhesins trigger cell membrane receptor clustering and activation of the linked cell signaling pathways, promote structural and functional cell lesions and injuries in intestinal barrier, induce proinflammatory responses, create angiogenesis, instigate epithelial-mesenchymal transition-like events, and lead to pks-dependent DNA damage. UTI-associated Afa/Dr DAEC strains, following adhesin-membrane receptor cell interactions and activation of associated lipid raft-dependent cell signaling pathways, internalize in a microtubule-dependent manner within urinary tract epithelial cells, develop a particular intracellular lifestyle, and trigger a toxin-dependent cell detachment. In response to Afa/Dr DAEC infection, the host epithelial cells generate antibacterial defense responses. Finally, I discuss a hypothetical role of intestinal Afa/Dr DAEC strains that can act as "silent pathogens" with the capacity to emerge as "pathobionts" for the development of inflammatory bowel disease and intestinal carcinogenesis.
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Scholz R, Imami K, Scott NE, Trimble WS, Foster LJ, Finlay BB. Novel Host Proteins and Signaling Pathways in Enteropathogenic E. coli Pathogenesis Identified by Global Phosphoproteome Analysis. Mol Cell Proteomics 2015; 14:1927-45. [PMID: 25944883 DOI: 10.1074/mcp.m114.046847] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Indexed: 12/21/2022] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) uses a type III secretion system (T3SS) to directly translocate effector proteins into host cells where they play a pivotal role in subverting host cell signaling needed for disease. However, our knowledge of how EPEC affects host protein phosphorylation is limited to a few individual protein studies. We employed a quantitative proteomics approach to globally map alterations in the host phosphoproteome during EPEC infection. By characterizing host phosphorylation events at various time points throughout infection, we examined how EPEC dynamically impacts the host phosphoproteome over time. This experimental setup also enabled identification of T3SS-dependent and -independent changes in host phosphorylation. Specifically, T3SS-regulated events affected various cellular processes that are known EPEC targets, including cytoskeletal organization, immune signaling, and intracellular trafficking. However, the involvement of phosphorylation in these events has thus far been poorly studied. We confirmed the MAPK family as an established key host player, showed its central role in signal transduction during EPEC infection, and extended the repertoire of known signaling hubs with previously unrecognized proteins, including TPD52, CIN85, EPHA2, and HSP27. We identified altered phosphorylation of known EPEC targets, such as cofilin, where the involvement of phosphorylation has so far been undefined, thus providing novel mechanistic insights into the roles of these proteins in EPEC infection. An overlap of regulated proteins, especially those that are cytoskeleton-associated, was observed when compared with the phosphoproteome of Shigella-infected cells. We determined the biological relevance of the phosphorylation of a novel protein in EPEC pathogenesis, septin-9 (SEPT9). Both siRNA knockdown and a phosphorylation-impaired SEPT9 mutant decreased bacterial adherence and EPEC-mediated cell death. In contrast, a phosphorylation-mimicking SEPT9 mutant rescued these effects. Collectively, this study provides the first global analysis of phosphorylation-mediated processes during infection with an extracellular, diarrheagenic bacterial pathogen.
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Affiliation(s)
| | - Koshi Imami
- §Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Nichollas E Scott
- §Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - William S Trimble
- ¶Cell Biology Program, Hospital for Sick Children and ‖Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1X8, Canada
| | - Leonard J Foster
- §Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada, **Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada, and
| | - B Brett Finlay
- From the ‡Michael Smith Laboratories and **Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada, and ¶¶Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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Identification and regulation of a novel Citrobacter rodentium gut colonization fimbria (Gcf). J Bacteriol 2015; 197:1478-91. [PMID: 25666139 DOI: 10.1128/jb.02486-14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
UNLABELLED The Gram-negative enteric bacterium Citrobacter rodentium is a natural mouse pathogen that has been extensively used as a surrogate model for studying the human pathogens enteropathogenic and enterohemorrhagic Escherichia coli. All three pathogens produce similar attaching and effacing (A/E) lesions in the intestinal epithelium. During infection, these bacteria employ surface structures called fimbriae to adhere and colonize the host intestinal epithelium. For C. rodentium, the roles of only a small number of its genome-carried fimbrial operons have been evaluated. Here, we report the identification of a novel C. rodentium colonization factor, called gut colonization fimbria (Gcf), which is encoded by a chaperone-usher fimbrial operon. A gcfA mutant shows a severe colonization defect within the first 10 days of infection. The gcf promoter is not active in C. rodentium under several in vitro growth conditions; however, it is readily expressed in a C. rodentium Δhns1 mutant lacking the closest ortholog of the Escherichia coli histone-like nucleoid structuring protein (H-NS) but not in mutants with deletion of the other four genes encoding H-NS homologs. H-NS binds to the regulatory region of gcf, further supporting its direct role as a repressor of the gcf promoter that starts transcription 158 bp upstream of the start codon of its first open reading frame. The gcf operon possesses interesting novel traits that open future opportunities to expand our knowledge of the structure, regulation, and function during infection of these important bacterial structures. IMPORTANCE Fimbriae are surface bacterial structures implicated in a variety of biological processes. Some have been shown to play a critical role during host colonization and thus in disease. Pathogenic bacteria possess the genetic information for an assortment of fimbriae, but their function and regulation and the interplay between them have not been studied in detail. This work provides new insights into the function and regulation of a novel fimbria called Gcf that is important for early establishment of a successful infection by C. rodentium in mice, despite being poorly expressed under in vitro growth conditions. This discovery offers an opportunity to better understand the individual role and the regulatory mechanisms controlling the expression of specific fimbrial operons that are critical during infection.
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The secreted effector protein EspZ is essential for virulence of rabbit enteropathogenic Escherichia coli. Infect Immun 2015; 83:1139-49. [PMID: 25561713 DOI: 10.1128/iai.02876-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Attaching and effacing (A/E) pathogens adhere intimately to intestinal enterocytes and efface brush border microvilli. A key virulence strategy of A/E pathogens is the type III secretion system (T3SS)-mediated delivery of effector proteins into host cells. The secreted protein EspZ is postulated to promote enterocyte survival by regulating the T3SS and/or by modulating epithelial signaling pathways. To explore the role of EspZ in A/E pathogen virulence, we generated an isogenic espZ deletion strain (ΔespZ) and corresponding cis-complemented derivatives of rabbit enteropathogenic Escherichia coli and compared their abilities to regulate the T3SS and influence host cell survival in vitro. For virulence studies, rabbits infected with these strains were monitored for bacterial colonization, clinical signs, and intestinal tissue alterations. Consistent with data from previous reports, espZ-transfected epithelial cells were refractory to infection-dependent effector translocation. Also, the ΔespZ strain induced greater host cell death than did the parent and complemented strains. In rabbit infections, fecal ΔespZ strain levels were 10-fold lower than those of the parent strain at 1 day postinfection, while the complemented strain was recovered at intermediate levels. In contrast to the parent and complemented mutants, ΔespZ mutant fecal carriage progressively decreased on subsequent days. ΔespZ mutant-infected animals gained weight steadily over the infection period, failed to show characteristic disease symptoms, and displayed minimal infection-induced histological alterations. Terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) staining of intestinal sections revealed increased epithelial cell apoptosis on day 1 after infection with the ΔespZ strain compared to animals infected with the parent or complemented strains. Thus, EspZ-dependent host cell cytoprotection likely prevents epithelial cell death and sloughing and thereby promotes bacterial colonization.
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Enterohemorrhagic Escherichia coli colonization of human colonic epithelium in vitro and ex vivo. Infect Immun 2014; 83:942-9. [PMID: 25534942 PMCID: PMC4333473 DOI: 10.1128/iai.02928-14] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) is an important foodborne pathogen causing gastroenteritis and more severe complications, such as hemorrhagic colitis and hemolytic uremic syndrome. Pathology is most pronounced in the colon, but to date there is no direct clinical evidence showing EHEC binding to the colonic epithelium in patients. In this study, we investigated EHEC adherence to the human colon by using in vitro organ culture (IVOC) of colonic biopsy samples and polarized T84 colon carcinoma cells. We show for the first time that EHEC colonizes human colonic biopsy samples by forming typical attaching and effacing (A/E) lesions which are dependent on EHEC type III secretion (T3S) and binding of the outer membrane protein intimin to the translocated intimin receptor (Tir). A/E lesion formation was dependent on oxygen levels and suppressed under oxygen-rich culture conditions routinely used for IVOC. In contrast, EHEC adherence to polarized T84 cells occurred independently of T3S and intimin and did not involve Tir translocation into the host cell membrane. Colonization of neither biopsy samples nor T84 cells was significantly affected by expression of Shiga toxins. Our study suggests that EHEC colonizes and forms stable A/E lesions on the human colon, which are likely to contribute to intestinal pathology during infection. Furthermore, care needs to be taken when using cell culture models, as they might not reflect the in vivo situation.
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Abstract
Citrobacter rodentium is a mucosal pathogen of mice that shares several pathogenic mechanisms with enteropathogenic Escherichia coli (EPEC) and enterohaemorrhagic E. coli (EHEC), which are two clinically important human gastrointestinal pathogens. Thus, C. rodentium has long been used as a model to understand the molecular basis of EPEC and EHEC infection in vivo. In this Review, we discuss recent studies in which C. rodentium has been used to study mucosal immunology, including the deregulation of intestinal inflammatory responses during bacteria-induced colitis and the role of the intestinal microbiota in mediating resistance to colonization by enteric pathogens. These insights should help to elucidate the roles of mucosal inflammatory responses and the microbiota in the virulence of enteric pathogens.
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Crabbé A, Ledesma MA, Nickerson CA. Mimicking the host and its microenvironment in vitro for studying mucosal infections by Pseudomonas aeruginosa. Pathog Dis 2014; 71:1-19. [PMID: 24737619 DOI: 10.1111/2049-632x.12180] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 04/09/2014] [Accepted: 04/09/2014] [Indexed: 02/01/2023] Open
Abstract
Why is a healthy person protected from Pseudomonas aeruginosa infections, while individuals with cystic fibrosis or damaged epithelium are particularly susceptible to this opportunistic pathogen? To address this question, it is essential to thoroughly understand the dynamic interplay between the host microenvironment and P. aeruginosa. Therefore, using model systems that represent key aspects of human mucosal tissues in health and disease allows recreating in vivo host-pathogen interactions in a physiologically relevant manner. In this review, we discuss how factors of mucosal tissues, such as apical-basolateral polarity, junctional complexes, extracellular matrix proteins, mucus, multicellular complexity (including indigenous microbiota), and other physicochemical factors affect P. aeruginosa pathogenesis and are thus important to mimic in vitro. We highlight in vitro cell and tissue culture model systems of increasing complexity that have been used over the past 35 years to study the infectious disease process of P. aeruginosa, mainly focusing on lung models, and their respective advantages and limitations. Continued improvements of in vitro models based on our expanding knowledge of host microenvironmental factors that participate in P. aeruginosa pathogenesis will help advance fundamental understanding of pathogenic mechanisms and increase the translational potential of research findings from bench to the patient's bedside.
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Affiliation(s)
- Aurélie Crabbé
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, AZ, USA
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Thomassin JL, Lee MJ, Brannon JR, Sheppard DC, Gruenheid S, Le Moual H. Both group 4 capsule and lipopolysaccharide O-antigen contribute to enteropathogenic Escherichia coli resistance to human α-defensin 5. PLoS One 2013; 8:e82475. [PMID: 24324796 PMCID: PMC3853201 DOI: 10.1371/journal.pone.0082475] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 11/02/2013] [Indexed: 12/18/2022] Open
Abstract
Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) are food-borne pathogens that colonize the small intestine and colon, respectively. To cause disease, these pathogens must overcome the action of different host antimicrobial peptides (AMPs) secreted into these distinct niches. We have shown previously that EHEC expresses high levels of the OmpT protease to inactivate the human cathelicidin LL-37, an AMP present in the colon. In this study, we investigate the mechanisms used by EPEC to resist human α-defensin 5 (HD-5), the most abundant AMP in the small intestine. Quantitative PCR was used to measure transcript levels of various EPEC surface structures. High transcript levels of gfcA, a gene required for group 4 capsule (G4C) production, were observed in EPEC, but not in EHEC. The unencapsulated EPEC ∆gfcA and EHEC wild-type strains were more susceptible to HD-5 than EPEC wild-type. Since the G4C is composed of the same sugar repeats as the lipopolysaccharide O-antigen, an -antigen ligase (waaL) deletion mutant was generated in EPEC to assess its role in HD-5 resistance. The ∆waaL EPEC strain was more susceptible to HD-5 than both the wild-type and ∆gfcA strains. The ∆gfcA∆waaL EPEC strain was not significantly more susceptible to HD-5 than the ∆waaL strain, suggesting that the absence of -antigen influences G4C formation. To determine whether the G4C and -antigen interact with HD-5, total polysaccharide was purified from wild-type EPEC and added to the ∆gfcA∆waaL strain in the presence of HD-5. The addition of exogenous polysaccharide protected the susceptible strain against HD-5 killing in a dose-dependent manner, suggesting that HD-5 binds to the polysaccharides present on the surface of EPEC. Altogether, these findings indicate that EPEC relies on both the G4C and the -antigen to resist the bactericidal activity of HD-5.
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Affiliation(s)
- Jenny-Lee Thomassin
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Mark J. Lee
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - John R. Brannon
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Donald C. Sheppard
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Microbiome and Disease Tolerance Centre, McGill University, Montreal, Quebec, Canada
| | - Samantha Gruenheid
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Microbiome and Disease Tolerance Centre, McGill University, Montreal, Quebec, Canada
| | - Hervé Le Moual
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Microbiome and Disease Tolerance Centre, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
- * E-mail:
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Real-time sensing of enteropathogenic E. coli-induced effects on epithelial host cell height, cell-substrate interactions, and endocytic processes by infrared surface plasmon spectroscopy. PLoS One 2013; 8:e78431. [PMID: 24194932 PMCID: PMC3806826 DOI: 10.1371/journal.pone.0078431] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 09/19/2013] [Indexed: 12/12/2022] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) is an important, generally non-invasive, bacterial pathogen that causes diarrhea in humans. The microbe infects mainly the enterocytes of the small intestine. Here we have applied our newly developed infrared surface plasmon resonance (IR-SPR) spectroscopy approach to study how EPEC infection affects epithelial host cells. The IR-SPR experiments showed that EPEC infection results in a robust reduction in the refractive index of the infected cells. Assisted by confocal and total internal reflection microscopy, we discovered that the microbe dilates the intercellular gaps and induces the appearance of fluid-phase-filled pinocytic vesicles in the lower basolateral regions of the host epithelial cells. Partial cell detachment from the underlying substratum was also observed. Finally, the waveguide mode observed by our IR-SPR analyses showed that EPEC infection decreases the host cell's height to some extent. Together, these observations reveal novel impacts of the pathogen on the host cell architecture and endocytic functions. We suggest that these changes may induce the infiltration of a watery environment into the host cell, and potentially lead to failure of the epithelium barrier functions. Our findings also indicate the great potential of the label-free IR-SPR approach to study the dynamics of host-pathogen interactions with high spatiotemporal sensitivity.
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