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von Beek C, Fahlgren A, Geiser P, Di Martino ML, Lindahl O, Prensa GI, Mendez-Enriquez E, Eriksson J, Hallgren J, Fällman M, Pejler G, Sellin ME. A two-step activation mechanism enables mast cells to differentiate their response between extracellular and invasive enterobacterial infection. Nat Commun 2024; 15:904. [PMID: 38291037 PMCID: PMC10828507 DOI: 10.1038/s41467-024-45057-w] [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: 03/15/2023] [Accepted: 01/12/2024] [Indexed: 02/01/2024] Open
Abstract
Mast cells localize to mucosal tissues and contribute to innate immune defense against infection. How mast cells sense, differentiate between, and respond to bacterial pathogens remains a topic of ongoing debate. Using the prototype enteropathogen Salmonella Typhimurium (S.Tm) and other related enterobacteria, here we show that mast cells can regulate their cytokine secretion response to distinguish between extracellular and invasive bacterial infection. Tissue-invasive S.Tm and mast cells colocalize in the mouse gut during acute Salmonella infection. Toll-like Receptor 4 (TLR4) sensing of extracellular S.Tm, or pure lipopolysaccharide, causes a modest induction of cytokine transcripts and proteins, including IL-6, IL-13, and TNF. By contrast, type-III-secretion-system-1 (TTSS-1)-dependent S.Tm invasion of both mouse and human mast cells triggers rapid and potent inflammatory gene expression and >100-fold elevated cytokine secretion. The S.Tm TTSS-1 effectors SopB, SopE, and SopE2 here elicit a second activation signal, including Akt phosphorylation downstream of effector translocation, which combines with TLR activation to drive the full-blown mast cell response. Supernatants from S.Tm-infected mast cells boost macrophage survival and maturation from bone-marrow progenitors. Taken together, this study shows that mast cells can differentiate between extracellular and host-cell invasive enterobacteria via a two-step activation mechanism and tune their inflammatory output accordingly.
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Affiliation(s)
- Christopher von Beek
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Anna Fahlgren
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Petra Geiser
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | | | - Otto Lindahl
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Grisna I Prensa
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Erika Mendez-Enriquez
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Jens Eriksson
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Jenny Hallgren
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Maria Fällman
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Gunnar Pejler
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
| | - Mikael E Sellin
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
- Science for Life Laboratory, Uppsala, Sweden.
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2
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Cruz E, Haeberle AL, Westerman TL, Durham ME, Suyemoto MM, Knodler LA, Elfenbein JR. Nonredundant Dimethyl Sulfoxide Reductases Influence Salmonella enterica Serotype Typhimurium Anaerobic Growth and Virulence. Infect Immun 2023; 91:e0057822. [PMID: 36722978 PMCID: PMC9933680 DOI: 10.1128/iai.00578-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 01/10/2023] [Indexed: 02/02/2023] Open
Abstract
Facultative anaerobic enteric pathogens can utilize a diverse array of alternate electron acceptors to support anaerobic metabolism and thrive in the hypoxic conditions within the mammalian gut. Dimethyl sulfoxide (DMSO) is produced by methionine catabolism and can act as an alternate electron acceptor to support anaerobic respiration. The DMSO reductase complex consists of three subunits, DmsA, DmsB, and DmsC, and allows bacteria to grow anaerobically with DMSO as an electron acceptor. The genomes of nontyphoidal Salmonella enterica encode three putative dmsABC operons, but the impact of the apparent genetic redundancy in DMSO reduction on the fitness of nontyphoidal S. enterica during infection remains unknown. We hypothesized that DMSO reduction would be needed for S. enterica serotype Typhimurium to colonize the mammalian gut. We demonstrate that an S. Typhimurium mutant with loss of function in all three putative DMSO reductases (ΔdmsA3) poorly colonizes the mammalian intestine when the microbiota is intact and when inflammation is absent. DMSO reduction enhances anaerobic growth through nonredundant contributions of two of the DMSO reductases. Furthermore, DMSO reduction influences virulence by increasing expression of the type 3 secretion system 2 and reducing expression of the type 3 secretion system 1. Collectively, our data demonstrate that the DMSO reductases of S. Typhimurium are functionally nonredundant and suggest DMSO is a physiologically relevant electron acceptor that supports S. enterica fitness in the gut.
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Affiliation(s)
- E. Cruz
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - A. L. Haeberle
- Paul G. Allen School for Global Health, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - T. L. Westerman
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - M. E. Durham
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - M. M. Suyemoto
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - L. A. Knodler
- Paul G. Allen School for Global Health, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - J. R. Elfenbein
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
- Food Research Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
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3
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Hoffman D, Tevet Y, Trzebanski S, Rosenberg G, Vainman L, Solomon A, Hen-Avivi S, Ben-Moshe NB, Avraham R. A non-classical monocyte-derived macrophage subset provides a splenic replication niche for intracellular Salmonella. Immunity 2021; 54:2712-2723.e6. [PMID: 34788598 PMCID: PMC8691386 DOI: 10.1016/j.immuni.2021.10.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 07/27/2021] [Accepted: 10/18/2021] [Indexed: 12/24/2022]
Abstract
Interactions between intracellular bacteria and mononuclear phagocytes give rise to diverse cellular phenotypes that may determine the outcome of infection. Recent advances in single-cell RNA sequencing (scRNA-seq) have identified multiple subsets within the mononuclear population, but implications to their function during infection are limited. Here, we surveyed the mononuclear niche of intracellular Salmonella Typhimurium (S.Tm) during early systemic infection in mice. We described eclipse-like growth kinetics in the spleen, with a first phase of bacterial control mediated by tissue-resident red-pulp macrophages. A second phase involved extensive bacterial replication within a macrophage population characterized by CD9 expression. We demonstrated that CD9+ macrophages induced pathways for detoxificating oxidized lipids, that may be utilized by intracellular S.Tm. We established that CD9+ macrophages originated from non-classical monocytes (NCM), and NCM-depleted mice were more resistant to S.Tm infection. Our study defines macrophage subset-specific host-pathogen interactions that determine early infection dynamics and infection outcome of the entire organism. At early stages, Salmonella kinetics follows an eclipse-like dynamics CD9 Macs are an intracellular replication niche for Salmonella during eclipse CD9 Macs derive from non-classical monocytes and induce pathways to detoxify oxLDL CD9 Macs depletion reduces Salmonella infection and prolongs mice survival
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Affiliation(s)
- Dotan Hoffman
- Department of Biological Regulation, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Yaara Tevet
- Department of Biological Regulation, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Sébastien Trzebanski
- Department of Immunology, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Gili Rosenberg
- Department of Biological Regulation, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Leia Vainman
- Department of Biological Regulation, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Aryeh Solomon
- Department of Biological Regulation, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Shelly Hen-Avivi
- Department of Biological Regulation, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Noa Bossel Ben-Moshe
- Department of Biological Regulation, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Roi Avraham
- Department of Biological Regulation, Weizmann Institute of Science, 7610001 Rehovot, Israel.
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4
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Fattinger SA, Sellin ME, Hardt WD. Salmonella effector driven invasion of the gut epithelium: breaking in and setting the house on fire. Curr Opin Microbiol 2021; 64:9-18. [PMID: 34492596 DOI: 10.1016/j.mib.2021.08.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/10/2021] [Accepted: 08/17/2021] [Indexed: 12/15/2022]
Abstract
Salmonella Typhimurium (S.Tm) is a major cause of diarrheal disease. The invasion into intestinal epithelial cells (IECs) is a central step in the infection cycle. It is associated with gut inflammation and thought to benefit S.Tm proliferation also in the intestinal lumen. Importantly, it is still not entirely clear how inflammation is elicited and to which extent it links to IEC invasion efficiency in vivo. In this review, we summarize recent findings explaining IEC invasion by type-three-secretion-system-1 (TTSS-1) effector proteins and discuss their effects on invasion and gut inflammation. In non-polarized tissue culture cells, the TTSS-1 effectors (mainly SopB/E/E2) elicit large membrane ruffles fueling cooperative invasion, and can directly trigger pro-inflammatory signaling. By contrast, in the murine gut, we observe discreet-invasion (mainly via the TTSS-1 effector SipA) and a prominent pro-inflammatory role of the host?"s epithelial inflammasome(s), which sense pathogen associated molecular patterns (PAMPs). We discuss why it has remained a major challenge to tease apart direct and indirect inflammatory effects of TTSS-1 effectors and explain why further research will be needed to fully determine their inflammation-modulating role(s).
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Affiliation(s)
- Stefan A Fattinger
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland; Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
| | - Mikael E Sellin
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
| | - Wolf-Dietrich Hardt
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland.
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5
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Fattinger SA, Böck D, Di Martino ML, Deuring S, Samperio Ventayol P, Ek V, Furter M, Kreibich S, Bosia F, Müller-Hauser AA, Nguyen BD, Rohde M, Pilhofer M, Hardt WD, Sellin ME. Salmonella Typhimurium discreet-invasion of the murine gut absorptive epithelium. PLoS Pathog 2020; 16:e1008503. [PMID: 32365138 PMCID: PMC7224572 DOI: 10.1371/journal.ppat.1008503] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 05/14/2020] [Accepted: 03/26/2020] [Indexed: 01/15/2023] Open
Abstract
Salmonella enterica serovar Typhimurium (S.Tm) infections of cultured cell lines have given rise to the ruffle model for epithelial cell invasion. According to this model, the Type-Three-Secretion-System-1 (TTSS-1) effectors SopB, SopE and SopE2 drive an explosive actin nucleation cascade, resulting in large lamellipodia- and filopodia-containing ruffles and cooperative S.Tm uptake. However, cell line experiments poorly recapitulate many of the cell and tissue features encountered in the host’s gut mucosa. Here, we employed bacterial genetics and multiple imaging modalities to compare S.Tm invasion of cultured epithelial cell lines and the gut absorptive epithelium in vivo in mice. In contrast to the prevailing ruffle-model, we find that absorptive epithelial cell entry in the mouse gut occurs through “discreet-invasion”. This distinct entry mode requires the conserved TTSS-1 effector SipA, involves modest elongation of local microvilli in the absence of expansive ruffles, and does not favor cooperative invasion. Discreet-invasion preferentially targets apicolateral hot spots at cell–cell junctions and shows strong dependence on local cell neighborhood. This proof-of-principle evidence challenges the current model for how S.Tm can enter gut absorptive epithelial cells in their intact in vivo context. Bacterial pathogens can use secreted effector molecules to drive entry into host cells. Studies of the intestinal pathogen S.Tm have been central to uncover the mechanistic basis for the entry process. More than two decades of research have resulted in a detailed model for how S.Tm invades gut epithelial cells through effector triggering of large Rho-GTPase-dependent actin ruffles. However, the evidence for this model comes predominantly from studies in cultured cell lines. These experimental systems lack many of the architectural and signaling features of the intact gut epithelium. Our study surprisingly reveals that in the intact mouse gut, S.Tm invades absorptive epithelial cells through a process that does not require the Rho-GTPase-activating effectors and can proceed in the absence of the prototypical ruffling response. Instead, S.Tm exploits another effector, SipA, to sneak in through discreet entry structures close to cell–cell junctions. Our results challenge the current model for S.Tm epithelial cell entry and emphasizes the need of taking a physiological host cell context into account when studying bacterium–host cell interactions.
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Affiliation(s)
- Stefan A. Fattinger
- Institute of Microbiology, Department of Biology, ETH Zürich, Zürich, Switzerland
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Desirée Böck
- Institute of Molecular Biology & Biophysics, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Maria Letizia Di Martino
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Sabrina Deuring
- Institute of Microbiology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Pilar Samperio Ventayol
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Viktor Ek
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Markus Furter
- Institute of Microbiology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Saskia Kreibich
- Institute of Microbiology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Francesco Bosia
- Institute of Molecular Biology & Biophysics, Department of Biology, ETH Zürich, Zürich, Switzerland
| | | | - Bidong D. Nguyen
- Institute of Microbiology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Martin Pilhofer
- Institute of Molecular Biology & Biophysics, Department of Biology, ETH Zürich, Zürich, Switzerland
- * E-mail: (MP); (WDH); (MES)
| | - Wolf-Dietrich Hardt
- Institute of Microbiology, Department of Biology, ETH Zürich, Zürich, Switzerland
- * E-mail: (MP); (WDH); (MES)
| | - Mikael E. Sellin
- Institute of Microbiology, Department of Biology, ETH Zürich, Zürich, Switzerland
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- * E-mail: (MP); (WDH); (MES)
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6
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Chong A, Starr T, Finn CE, Steele-Mortimer O. A role for the Salmonella Type III Secretion System 1 in bacterial adaptation to the cytosol of epithelial cells. Mol Microbiol 2019; 112:1270-1283. [PMID: 31370104 DOI: 10.1111/mmi.14361] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2019] [Indexed: 12/15/2022]
Abstract
Salmonella enterica serovar Typhimurium is a facultative intracellular pathogen that invades the intestinal epithelium. Following invasion of epithelial cells, Salmonella survives and replicates within two distinct intracellular niches. While all of the bacteria are initially taken up into a membrane bound vacuole, the Salmonella-containing vacuole or SCV, a significant proportion of them promptly escape into the cytosol. Cytosolic Salmonella replicates more rapidly compared to the vacuolar population, although the reasons for this are not well understood. SipA, a multi-function effector protein, has been shown to affect intracellular replication and is secreted by cytosolic Salmonella via the invasion-associated Type III Secretion System 1 (T3SS1). Here, we have used a multipronged microscopy approach to show that SipA does not affect bacterial replication rates per se, but rather mediates intra-cytosolic survival and/or initiation of replication following bacterial egress from the SCV. Altogether, our findings reveal an important role for SipA in the early survival of cytosolic Salmonella.
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Affiliation(s)
- Audrey Chong
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Tregei Starr
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Ciaran E Finn
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Olivia Steele-Mortimer
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
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7
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Ferrari RG, Rosario DKA, Cunha-Neto A, Mano SB, Figueiredo EES, Conte-Junior CA. Worldwide Epidemiology of Salmonella Serovars in Animal-Based Foods: a Meta-analysis. Appl Environ Microbiol 2019; 85:e00591-19. [PMID: 31053586 PMCID: PMC6606869 DOI: 10.1128/aem.00591-19] [Citation(s) in RCA: 282] [Impact Index Per Article: 56.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 04/25/2019] [Indexed: 01/27/2023] Open
Abstract
Salmonella spp. are among the most important foodborne pathogens and the third leading cause of human death among diarrheal diseases worldwide. Animals are the primary source of this pathogen, and animal-based foods are the main transmission route to humans. Thus, understanding the global epidemiology of Salmonella serovars is key to controlling and monitoring this bacterium. In this context, this study aimed to evaluate the prevalence and diversity of Salmonella enterica serovars in animal-based foods (beef, pork, poultry, and seafood) throughout the five continents (Africa, the Americas [North and Latin America], Asia, Europe, and Oceania). The meta-analysis consisted of a chemometric assessment (hierarchical cluster analysis and principal component analysis) to identify the main epidemiological findings, including the prevalence and diversity of the Salmonella serovars in each matrix. Regarding the serovar distribution, S Typhimurium presented a cosmopolitan distribution, reported in all four assessed matrices and continents; poultry continues to play a central role in the dissemination of the Enteritidis serovar to humans, and Anatum and Weltevreden were the most frequently found in beef and seafood, respectively. Additionally, we recommended careful monitoring of certain serovars, such as Derby, Agona, Infantis, and Kentucky. Finally, given the scientific data regarding the most frequently reported serovars and which matrices constitute the main vehicles for the transmission of this pathogen, control programs may be improved, and specific interventions may be implemented in an attempt to reduce the risk of this pathogen reaching humans.IMPORTANCE Salmonellosis is caused by Salmonella spp. and is the third leading cause of death among food-transmitted diseases. This pathogen is commonly disseminated in domestic and wild animals, and the infection's symptoms are characterized by acute fever, nausea, abdominal pain, and diarrhea. The animals are the primary source of salmonellae, and animal-based foods are the main transmission route to humans. Therefore, data collected from these sources could contribute to future global interventions for effective control and surveillance of Salmonella along the food chain. In light of this, the importance of our research is in identifying the prevalence of Salmonella serovars in four animal-based food matrices (pork, poultry, beef, and seafood) and to evaluate the importance that each matrix has as the primary source of this pathogen to humans.
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Affiliation(s)
- Rafaela G Ferrari
- Molecular and Analytical Laboratory Center, Department of Food Technology, Faculty of Veterinary, Federal Fluminense University, Niterói, Brazil
- Post Graduate Program in Food Science Program, Institute of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Denes K A Rosario
- Molecular and Analytical Laboratory Center, Department of Food Technology, Faculty of Veterinary, Federal Fluminense University, Niterói, Brazil
- Post Graduate Program in Food Science Program, Institute of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Adelino Cunha-Neto
- Molecular and Analytical Laboratory Center, Department of Food Technology, Faculty of Veterinary, Federal Fluminense University, Niterói, Brazil
- Nutrition, Food and Metabolism Program, Nutrition Faculty, Federal University of Mato Grosso, Cuiabá, Brazil
| | - Sérgio B Mano
- Molecular and Analytical Laboratory Center, Department of Food Technology, Faculty of Veterinary, Federal Fluminense University, Niterói, Brazil
| | - Eduardo E S Figueiredo
- Animal Science Program, Faculty of Agronomy and Animal Science, Federal University of Mato Grosso, Cuiabá, Brazil
- Nutrition, Food and Metabolism Program, Nutrition Faculty, Federal University of Mato Grosso, Cuiabá, Brazil
| | - Carlos A Conte-Junior
- Molecular and Analytical Laboratory Center, Department of Food Technology, Faculty of Veterinary, Federal Fluminense University, Niterói, Brazil
- Post Graduate Program in Food Science Program, Institute of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- National Institute of Health Quality Control, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
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8
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Barcoded Consortium Infections Resolve Cell Type-Dependent Salmonella enterica Serovar Typhimurium Entry Mechanisms. mBio 2019; 10:mBio.00603-19. [PMID: 31113898 PMCID: PMC6529635 DOI: 10.1128/mbio.00603-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Salmonella enterica serovar Typhimurium (S.Tm) is a widespread and broad-host-spectrum enteropathogen with the capacity to invade diverse cell types. Still, the molecular basis for the host cell invasion process has largely been inferred from studies of a few selected cell lines. Our work resolves the mechanisms that Salmonellae employ to invade prototypical host cell types, i.e., human epithelial, monocyte, and macrophage cells, at a previously unattainable level of temporal and quantitative precision. This highlights efficient bacterium-driven entry into innate immune cells and uncovers a type III secretion system effector module that dominates active bacterial invasion of not only epithelial cells but also monocytes and macrophages. The results are derived from a generalizable method, where we combine barcoding of the bacterial chromosome with mixed consortium infections of cultured host cells. The application of this methodology across bacterial species and infection models will provide a scalable means to address host-pathogen interactions in diverse contexts. Bacterial host cell invasion mechanisms depend on the bacterium’s virulence factors and the properties of the target cell. The enteropathogen Salmonella enterica serovar Typhimurium (S.Tm) invades epithelial cell types in the gut mucosa and a variety of immune cell types at later infection stages. The molecular mechanism(s) of host cell entry has, however, been studied predominantly in epithelial cell lines. S.Tm uses a type three secretion system (TTSS-1) to translocate effectors into the host cell cytosol, thereby sparking actin ruffle-dependent entry. The ruffles also fuel cooperative invasion by bystander bacteria. In addition, several TTSS-1-independent entry mechanisms exist, involving alternative S.Tm virulence factors, or the passive uptake of bacteria by phagocytosis. However, it remains ill-defined how S.Tm invasion mechanisms vary between host cells. Here, we developed an internally controlled and scalable method to map S.Tm invasion mechanisms across host cell types and conditions. The method relies on host cell infections with consortia of chromosomally tagged wild-type and mutant S.Tm strains, where the abundance of each strain can be quantified by qPCR or amplicon sequencing. Using this methodology, we quantified cooccurring TTSS-1-dependent, cooperative, and TTSS-1-independent invasion events in epithelial, monocyte, and macrophage cells. We found S.Tm invasion of epithelial cells and monocytes to proceed by a similar MOI-dependent mix of TTSS-1-dependent and cooperative mechanisms. TTSS-1-independent entry was more frequent in macrophages. Still, TTSS-1-dependent invasion dominated during the first minutes of interaction also with this cell type. Finally, the combined action of the SopB/SopE/SopE2 effectors was sufficient to explain TTSS-1-dependent invasion across both epithelial and phagocytic cells.
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9
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Yin Y, Zhou D. Organoid and Enteroid Modeling of Salmonella Infection. Front Cell Infect Microbiol 2018; 8:102. [PMID: 29670862 PMCID: PMC5894114 DOI: 10.3389/fcimb.2018.00102] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 03/16/2018] [Indexed: 12/12/2022] Open
Abstract
Salmonella are Gram-negative rod-shaped facultative anaerobic bacteria that are comprised of over 2,000 serovars. They cause gastroenteritis (salmonellosis) with headache, abdominal pain and diarrhea clinical symptoms. Salmonellosis brings a heavy burden for the public health in both developing and developed countries. Antibiotics are usually effective in treating the infected patients with severe gastroenteritis, although antibiotic resistance is on the rise. Understanding the molecular mechanisms of Salmonella infection is vital to combat the disease. In vitro immortalized 2-D cell lines, ex vivo tissues/organs and several animal models have been successfully utilized to study Salmonella infections. Although these infection models have contributed to uncovering the molecular virulence mechanisms, some intrinsic shortcomings have limited their wider applications. Notably, cell lines only contain a single cell type, which cannot reproduce some of the hallmarks of natural infections. While ex vivo tissues/organs alleviate some of these concerns, they are more difficult to maintain, in particular for long term experiments. In addition, non-human animal models are known to reflect only part of the human disease process. Enteroids and induced intestinal organoids are emerging as effective infection models due to their closeness in mimicking the infected tissues/organs. Induced intestinal organoids are derived from iPSCs and contain mesenchymal cells whereas enteroids are derive from intestinal stem cells and are comprised of epithelial cells only. Both enteroids and induced intestinal organoids mimic the villus and crypt domains comparable to the architectures of the in vivo intestine. We review here that enteroids and induced intestinal organoids are emerging as desired infection models to study bacterial-host interactions of Salmonella.
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Affiliation(s)
- Yuebang Yin
- Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center, Rotterdam, Netherlands
| | - Daoguo Zhou
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China.,Department of Biological Sciences, Purdue University, West Lafayette, IN, United States
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10
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Zhang K, Riba A, Nietschke M, Torow N, Repnik U, Pütz A, Fulde M, Dupont A, Hensel M, Hornef M. Minimal SPI1-T3SS effector requirement for Salmonella enterocyte invasion and intracellular proliferation in vivo. PLoS Pathog 2018. [PMID: 29522566 PMCID: PMC5862521 DOI: 10.1371/journal.ppat.1006925] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Effector molecules translocated by the Salmonella pathogenicity island (SPI)1-encoded type 3 secretion system (T3SS) critically contribute to the pathogenesis of human Salmonella infection. They facilitate internalization by non-phagocytic enterocytes rendering the intestinal epithelium an entry site for infection. Their function in vivo has remained ill-defined due to the lack of a suitable animal model that allows visualization of intraepithelial Salmonella. Here, we took advantage of our novel neonatal mouse model and analyzed various bacterial mutants and reporter strains as well as gene deficient mice. Our results demonstrate the critical but redundant role of SopE2 and SipA for enterocyte invasion, prerequisite for transcriptional stimulation and mucosal translocation in vivo. In contrast, the generation of a replicative intraepithelial endosomal compartment required the cooperative action of SipA and SopE2 or SipA and SopB but was independent of SopA or host MyD88 signaling. Intraepithelial growth had no critical influence on systemic spread. Our results define the role of SPI1-T3SS effector molecules during enterocyte invasion and intraepithelial proliferation in vivo providing novel insight in the early course of Salmonella infection. Non-typhoidal Salmonella represent a major causative agent of gastroenteritis worldwide. Hallmark of the pathogenesis is their ability to actively invade the intestinal epithelium by virtue of their type 3 secretion system that delivers bacterial virulence factors directly into the host cell cytosol. The role of these virulence factors during enterocyte entry and intraepithelial growth has only been investigated in vitro since the previously established in vivo models in small animals did not allow visualization of intraepithelial Salmonella. However, immortalized cell lines lack the overlaying mucus layer, final cell lineage differentiation, apical-basolateral polarization as well as continuous migration along the crypt villus axis and thus the role of virulence factors during the Salmonella infection in vivo has remained largely undefined. Here, we took advantage of our novel neonatal mouse infection model and for the first time systematically analyzed the importance of Salmonella virulence factors for enterocyte invasion and intraepithelial growth.
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Affiliation(s)
- Kaiyi Zhang
- Institute of Medical Microbiology, RWTH University Hospital, Aachen, Germany
| | - Ambre Riba
- Institute of Medical Microbiology, RWTH University Hospital, Aachen, Germany
| | - Monika Nietschke
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Natalia Torow
- Institute of Medical Microbiology, RWTH University Hospital, Aachen, Germany
| | - Urska Repnik
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Andreas Pütz
- Institute of Medical Microbiology, RWTH University Hospital, Aachen, Germany
| | - Marcus Fulde
- Institute of Microbiology and Epizootics, Freie Universität Berlin, Berlin, Germany
| | - Aline Dupont
- Institute of Medical Microbiology, RWTH University Hospital, Aachen, Germany
| | - Michael Hensel
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Mathias Hornef
- Institute of Medical Microbiology, RWTH University Hospital, Aachen, Germany
- * E-mail:
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11
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Yang HJ, Bogomolnaya L, McClelland M, Andrews-Polymenis H. De novo pyrimidine synthesis is necessary for intestinal colonization of Salmonella Typhimurium in chicks. PLoS One 2017; 12:e0183751. [PMID: 29040285 PMCID: PMC5644981 DOI: 10.1371/journal.pone.0183751] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 08/10/2017] [Indexed: 11/18/2022] Open
Abstract
pyrE (STM3733) encodes orotate phosphoribosyltransferase (OPRTase; EC 2.4.2.10), the fifth enzyme of the de novo pyrimidine biosynthetic pathway. We identified a ΔpyrE mutant as under selection in screening of a Salmonella mutant library in 4-day old chicks. Here, we confirm that a ΔpyrE mutant colonizes 4-day old chicks poorly in competitive infection with isogenic wild type, and that the ability of this mutant to colonize chicks could be restored by providing a copy of pyrE in trans. We further show that our ΔpyrE mutant grows poorly in nutrient poor conditions in vitro, and that the ability of this mutant to grow is restored, both in vitro and in chicks, when precursors to the pyrimidine salvage pathway were provided. This finding suggests that the environment in the chick intestine during our infections lacks sufficient precursors of the pyrimidine salvage pathway to support Salmonella growth. Finally, we show that the colonization defect of a ΔpyrE mutant during infection occurs in to chicks, but not in CBA/J mice or ligated ileal loops in calves. Our data suggest that de novo pyrimidine synthesis is necessary for colonization of Salmonella Typhimurium in the chick, and that the salvage pathway is not used in this niche.
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Affiliation(s)
- Hee-Jeong Yang
- Department of Microbial and Molecular Pathogenesis, College of Medicine, Texas A&M University System Health Science Center, Bryan, TX, United States of America
| | - Lydia Bogomolnaya
- Department of Microbial and Molecular Pathogenesis, College of Medicine, Texas A&M University System Health Science Center, Bryan, TX, United States of America
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Michael McClelland
- Department of Microbiology and Molecular Genetics, and Pathology and Laboratory Medicine, University of California, Irvine, CA, United States of America
| | - Helene Andrews-Polymenis
- Department of Microbial and Molecular Pathogenesis, College of Medicine, Texas A&M University System Health Science Center, Bryan, TX, United States of America
- * E-mail:
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12
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Zhang K, Griffiths G, Repnik U, Hornef M. Seeing is understanding: Salmonella's way to penetrate the intestinal epithelium. Int J Med Microbiol 2017; 308:97-106. [PMID: 28939439 DOI: 10.1016/j.ijmm.2017.09.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/06/2017] [Accepted: 09/11/2017] [Indexed: 02/06/2023] Open
Abstract
The molecular processes that govern host-microbial interaction illustrate not only the sophisticated and multifaceted mechanisms that protect the host from infection, but also the elaborated features of microbial pathogens that have evolved to overcome or evade the host's immune system. Here we focus on Salmonella that like other enteric pathogens must overcome the intestinal mucosal immune system, a surface constantly on alert and evolved to restrict the enteric microbiota. We discuss the initial step of Salmonella infection, the penetration of the intestinal epithelial barrier and the models used to study this fascinating aspect of microbial pathogenesis.
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Affiliation(s)
- Kaiyi Zhang
- Institute of Medical Microbiology, RWTH University Hospital Aachen, Aachen, Germany
| | | | - Urska Repnik
- Department of Biosciences, University of Oslo, Oslo, Norway.
| | - Mathias Hornef
- Institute of Medical Microbiology, RWTH University Hospital Aachen, Aachen, Germany.
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13
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Elfenbein JR, Knodler LA, Schaeffer AR, Faber F, Bäumler AJ, Andrews-Polymenis HL. A Salmonella Regulator Modulates Intestinal Colonization and Use of Phosphonoacetic Acid. Front Cell Infect Microbiol 2017; 7:69. [PMID: 28361036 PMCID: PMC5351497 DOI: 10.3389/fcimb.2017.00069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 02/23/2017] [Indexed: 11/21/2022] Open
Abstract
Many microorganisms produce phosphonates, molecules characterized by stable carbon-phosphorus bonds that store phosphorus or act as antimicrobials. The role of phosphonates in the marine biosphere is well characterized but the role of these molecules in the intestine is poorly understood. Salmonella enterica uses its virulence factors to influence the host immune response to compete with the host and normal microflora for nutrients. Salmonella cannot produce phosphonates but encodes the enzymes to use them suggesting that it is exposed to phosphonates during its life cycle. The role of phosphonates during enteric salmonellosis is unexplored. We have previously shown that STM3602, encoding a putative regulator of phosphonate metabolism, is needed for colonization in calves. Here, we report that the necessity of STM3602 in colonization of the murine intestine results from multiple factors. STM3602 is needed for full activation of the type-3 secretion system-1 and for optimal invasion of epithelial cells. The ΔSTM3602 mutant grows poorly in phosphonoacetic acid (PA) as the sole phosphorus source, but can use 2-aminoethylphosphonate. PhnA, an enzyme required for PA breakdown, is not controlled by STM3602 suggesting an additional mechanism for utilization of PA in S. Typhimurium. Finally, the requirement of STM3602 for intestinal colonization differs depending on the composition of the microflora. Our data suggest that STM3602 has multiple regulatory targets that are necessary for survival within the microbial community in the intestine. Determination of the members of the STM3602 regulon may illuminate new pathways needed for colonization of the host.
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Affiliation(s)
- Johanna R. Elfenbein
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University Health Science CenterBryan, TX, USA
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State UniversityRaleigh, NC, USA
| | - Leigh A. Knodler
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State UniversityPullman, WA, USA
| | - Allison R. Schaeffer
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University Health Science CenterBryan, TX, USA
| | - Franziska Faber
- Department of Medial Microbiology and Immunology, School of Medicine, University of California DavisDavis, CA, USA
| | - Andreas J. Bäumler
- Department of Medial Microbiology and Immunology, School of Medicine, University of California DavisDavis, CA, USA
| | - Helene L. Andrews-Polymenis
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University Health Science CenterBryan, TX, USA
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14
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Schulte M, Hensel M. Models of intestinal infection by Salmonella enterica: introduction of a new neonate mouse model. F1000Res 2016; 5. [PMID: 27408697 PMCID: PMC4926732 DOI: 10.12688/f1000research.8468.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/20/2016] [Indexed: 12/22/2022] Open
Abstract
Salmonella enterica serovar Typhimurium is a foodborne pathogen causing inflammatory disease in the intestine following diarrhea and is responsible for thousands of deaths worldwide. Many
in vitro investigations using cell culture models are available, but these do not represent the real natural environment present in the intestine of infected hosts. Several
in vivo animal models have been used to study the host-pathogen interaction and to unravel the immune responses and cellular processes occurring during infection. An animal model for
Salmonella-induced intestinal inflammation relies on the pretreatment of mice with streptomycin. This model is of great importance but still shows limitations to investigate the host-pathogen interaction in the small intestine
in vivo. Here, we review the use of mouse models for
Salmonella infections and focus on a new small animal model using 1-day-old neonate mice. The neonate model enables researchers to observe infection of both the small and large intestine, thereby offering perspectives for new experimental approaches, as well as to analyze the
Salmonella-enterocyte interaction in the small intestine
in vivo.
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Affiliation(s)
- Marc Schulte
- Department of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Michael Hensel
- Department of Microbiology, University of Osnabrück, Osnabrück, Germany
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15
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Jensen K, Gallagher IJ, Kaliszewska A, Zhang C, Abejide O, Gallagher MP, Werling D, Glass EJ. Live and inactivated Salmonella enterica serovar Typhimurium stimulate similar but distinct transcriptome profiles in bovine macrophages and dendritic cells. Vet Res 2016; 47:46. [PMID: 27000047 PMCID: PMC4802613 DOI: 10.1186/s13567-016-0328-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 02/17/2016] [Indexed: 01/10/2023] Open
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) is a major cause of gastroenteritis in cattle and humans. Dendritic cells (DC) and macrophages (Mø) are major players in early immunity to Salmonella, and their response could influence the course of infection. Therefore, the global transcriptional response of bovine monocyte-derived DC and Mø to stimulation with live and inactivated S. Typhimurium was compared. Both cell types mount a major response 2 h post infection, with a core common response conserved across cell-type and stimuli. However, three of the most affected pathways; inflammatory response, regulation of transcription and regulation of programmed cell death, exhibited cell-type and stimuli-specific differences. The expression of a subset of genes associated with these pathways was investigated further. The inflammatory response was greater in Mø than DC, in the number of genes and the enhanced expression of common genes, e.g., interleukin (IL) 1B and IL6, while the opposite pattern was observed with interferon gamma. Furthermore, a large proportion of the investigated genes exhibited stimuli-specific differential expression, e.g., Mediterranean fever. Two-thirds of the investigated transcription factors were significantly differentially expressed in response to live and inactivated Salmonella. Therefore the transcriptional responses of bovine DC and Mø during early S. Typhimurium infection are similar but distinct, potentially due to the overall function of these cell-types. The differences in response of the host cell will influence down-stream events, thus impacting on the subsequent immune response generated during the course of the infection.
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Affiliation(s)
- Kirsty Jensen
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, EH25 9RG, UK.
| | - Iain J Gallagher
- Health and Exercise Research Group, University of Stirling, Cottrell Building, Stirling, FK9 4LA, UK
| | - Anna Kaliszewska
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, EH25 9RG, UK
| | - Chen Zhang
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, EH25 9RG, UK
| | - Oluyinka Abejide
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, EH25 9RG, UK.,Scotland's Rural College, Easter Bush, Edinburgh, EH25 9RG, UK
| | - Maurice P Gallagher
- Institute of Cell Biology, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3JR, UK
| | - Dirk Werling
- Department of Pathology and Pathogen Biology, Royal Veterinary College, Hawkshead Lane, Hatfield, AL9 7TA, UK
| | - Elizabeth J Glass
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, EH25 9RG, UK
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16
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Brufau MT, Martín-Venegas R, Guerrero-Zamora AM, Pérez-Vendrell AM, Vilà B, Brufau J, Ferrer R. Dietary β-galactomannans have beneficial effects on the intestinal morphology of chickens challenged with Salmonella enterica serovar Enteritidis. J Anim Sci 2016; 93:238-46. [PMID: 25568372 DOI: 10.2527/jas.2014-7219] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Salmonella enterica serovar Enteritidis is one of the leading causes of food-borne salmonellosis in humans. Poultry is the single largest reservoir, and the consumption of incorrectly processed chicken meat and egg products is the major source of infection. Since 2006, the use of antibiotics as growth promoters has been banned in the European Union, and the dietary inclusion of β-galactomannans (βGM) has become a promising strategy to control and prevent intestinal infections. The aim of this study was to investigate the effect of various βGM-rich products on intestinal morphology in chickens challenged with Salmonella Enteritidis. To assess this effect, a total of 280 male Ross 308 chickens were studied (40 animals per treatment housed in 5 cages). There were 7 treatments, including controls: uninoculated birds fed the basal diet (negative control) and inoculated birds fed the basal diet (positive control) or the basal diet supplemented with Salmosan (1 g/kg), Duraió gum (1 g/kg), Cassia gum (1 g/kg), the cell walls of Saccharomyces cerevisiae (0.5 g/kg), or the antibiotic colistine (0.8 g/kg). The birds were fed these diets from the d 1 to 23, except the animals in the colistine group, which were fed the diet containing the antibiotic only from d 5 to 11. The inoculated animals were orally infected on d 7 with 10(8) cfu of Salmonella Enteritidis. Bird performance per replicate was determined for the whole study period (23 d), and the distal ileum and cecal tonsil of 5 animals per treatment (1 animal per replicate) were observed at different magnification levels (scanning electron, light, and laser confocal microscopy). In the images corresponding to the treatments containing βGM we observed more mucus, an effect that can be associated with the observation of more goblet cells. Moreover, the images also show fewer M cells, which are characteristic of infected animals. Regarding the morphometric parameters, the animals that received Duraió and Cassia gums show greater (P = 0.001 and P = 0.016, respectively) villus length compared with the animals in the positive control, thus indicating the capacity of these products to increase epithelial surface area. However, no effect (P > 0.05) on microvillus dimensions was detected. In conclusion, the results obtained indicating the beneficial effects of these βGM on intestinal morphology give more evidence of the positive effects of these supplements in poultry nutrition.
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Affiliation(s)
- M T Brufau
- Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, 08028 Barcelona, Spain
| | - R Martín-Venegas
- Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, 08028 Barcelona, Spain
| | - A M Guerrero-Zamora
- Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, 08028 Barcelona, Spain
| | - A M Pérez-Vendrell
- Institut de Recerca i Tecnologia Agroalimentàries, Monogastric Nutrition, 43120 Constantí, Spain
| | - B Vilà
- Institut de Recerca i Tecnologia Agroalimentàries, Monogastric Nutrition, 43120 Constantí, Spain
| | - J Brufau
- Institut de Recerca i Tecnologia Agroalimentàries, Monogastric Nutrition, 43120 Constantí, Spain
| | - R Ferrer
- Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, 08028 Barcelona, Spain
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17
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Verma S, Srikanth CV. Understanding the complexities of Salmonella-host crosstalk as revealed by in vivo model organisms. IUBMB Life 2015; 67:482-97. [PMID: 26179888 DOI: 10.1002/iub.1393] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 06/15/2015] [Indexed: 01/03/2023]
Abstract
Foodborne infections caused by non-typhoidal Salmonellae, such as Salmonella enterica serovar Typhimurium (ST), pose a major challenge in the developed and developing world. With constant rise of drug-resistant strains, understanding the epidemiology, microbiology, pathogenesis and host-pathogen interactions biology is a mandatory requirement to enable health systems to be ready to combat these illnesses. Patient data from hospitals, at least from some parts of the world, have aided in epidemiological understanding of ST-mediated disease. Most of the other aspects connected to Salmonella-host crosstalk have come from model systems that offer convenience, genetic tractability and low maintenance costs that make them extremely valuable tools. Complex model systems such as the bovine model have helped in understanding key virulence factors needed for infection. Simple systems such as fruit flies and Caenorhabditis elegans have aided in identification of novel virulence factors, host pathways and mechanistic details of interactions. Some of the path-breaking concepts of the field have come from mice model of ST colitis, which allows genetic manipulations as well as high degree of similarity to human counterpart. Together, they are invaluable for correlating in vitro findings of ST-induced disease progression in vivo. The current review is a compilation of various advances of ST-host interactions at cellular and molecular levels that has come from investigations involving model organisms.
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Affiliation(s)
- Smriti Verma
- Regional Centre for Biotechnology, NCR Biotech Cluster 3rd Milestone, Gurgaon-Faridabad Highway, Village Bhankari, Faridabad, Haryana, India
| | - Chittur V Srikanth
- Regional Centre for Biotechnology, NCR Biotech Cluster 3rd Milestone, Gurgaon-Faridabad Highway, Village Bhankari, Faridabad, Haryana, India
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18
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Knodler LA. Salmonella enterica: living a double life in epithelial cells. Curr Opin Microbiol 2015; 23:23-31. [DOI: 10.1016/j.mib.2014.10.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 10/16/2014] [Accepted: 10/24/2014] [Indexed: 02/07/2023]
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19
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Zhang K, Dupont A, Torow N, Gohde F, Leschner S, Lienenklaus S, Weiss S, Brinkmann MM, Kühnel M, Hensel M, Fulde M, Hornef MW. Age-dependent enterocyte invasion and microcolony formation by Salmonella. PLoS Pathog 2014; 10:e1004385. [PMID: 25210785 PMCID: PMC4161480 DOI: 10.1371/journal.ppat.1004385] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 08/05/2014] [Indexed: 12/13/2022] Open
Abstract
The coordinated action of a variety of virulence factors allows Salmonella enterica to invade epithelial cells and penetrate the mucosal barrier. The influence of the age-dependent maturation of the mucosal barrier for microbial pathogenesis has not been investigated. Here, we analyzed Salmonella infection of neonate mice after oral administration. In contrast to the situation in adult animals, we observed spontaneous colonization, massive invasion of enteroabsorptive cells, intraepithelial proliferation and the formation of large intraepithelial microcolonies. Mucosal translocation was dependent on enterocyte invasion in neonates in the absence of microfold (M) cells. It further resulted in potent innate immune stimulation in the absence of pronounced neutrophil-dominated pathology. Our results identify factors of age-dependent host susceptibility and provide important insight in the early steps of Salmonella infection in vivo. We also present a new small animal model amenable to genetic manipulation of the host for the analysis of the Salmonella enterocyte interaction in vivo. Non-typhoidal Salmonella are among of the most prevalent causative agents of infectious diarrheal disease worldwide but also very significantly contribute to infant sepsis and meningitis particularly in developing countries. The underlying mechanisms of the elevated susceptibility of the infant host to systemic Salmonella infection have not been investigated. Here we analyzed age-dependent differences in the colonization, mucosal translocation and systemic spread in a murine oral infection model. We observed efficient entry of Salmonella in intestinal epithelial cells of newborn mice. Enterocyte invasion was followed by massive bacterial proliferation and the formation of large intraepithelial bacterial colonies. Intraepithelial, but not non-invasive, extracellular Salmonella induced a potent immune stimulation. Also, enterocyte invasion was required for translocation through the mucosal barrier and spread of Salmonella to systemic organs. This requirement was due to the absence of M cells, specialized epithelial cells that forward luminal antigen to the underlying immune cells, in the neonate host. Our results identify age-dependent factors of host susceptibility and illustrate the initial phase of Salmonella infection. They further present a new small animal model amenable to genetic manipulation to investigate the interaction of this pathogen with epithelial cells and characterize the early steps in Salmonella pathogenesis.
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Affiliation(s)
- Kaiyi Zhang
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Aline Dupont
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Natalia Torow
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Fredrik Gohde
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Sara Leschner
- Department of Molecular Immunology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Stefan Lienenklaus
- Department of Molecular Immunology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Siegfried Weiss
- Department of Molecular Immunology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Melanie M. Brinkmann
- Department of Viral Immune Modulation, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Mark Kühnel
- Centre for Anatomy, Hannover Medical School, Hannover, Germany
| | - Michael Hensel
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Marcus Fulde
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
- * E-mail: (MF); (MWH)
| | - Mathias W. Hornef
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
- * E-mail: (MF); (MWH)
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20
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Inflammatory effects of Edwardsiella ictaluri lipopolysaccharide modifications in catfish gut. Infect Immun 2014; 82:3394-404. [PMID: 24866806 DOI: 10.1128/iai.01697-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacterial lipopolysaccharides (LPS) are structural components of the outer membranes of Gram-negative bacteria and also are potent inducers of inflammation in mammals. Higher vertebrates are extremely sensitive to LPS, but lower vertebrates, like fish, are resistant to their systemic toxic effects. However, the effects of LPS on the fish intestinal mucosa remain unknown. Edwardsiella ictaluri is a primitive member of the Enterobacteriaceae family that causes enteric septicemia in channel catfish (Ictalurus punctatus). E. ictaluri infects and colonizes deep lymphoid tissues upon oral or immersion infection. Both gut and olfactory organs are the primary sites of invasion. At the systemic level, E. ictaluri pathogenesis is relatively well characterized, but our knowledge about E. ictaluri intestinal interaction is limited. Recently, we observed that E. ictaluri oligo-polysaccharide (O-PS) LPS mutants have differential effects on the intestinal epithelia of orally inoculated catfish. Here we evaluate the effects of E. ictaluri O-PS LPS mutants by using a novel catfish intestinal loop model and compare it to the rabbit ileal loop model inoculated with Salmonella enterica serovar Typhimurium LPS. We found evident differences in rabbit ileal loop and catfish ileal loop responses to E. ictaluri and S. Typhimurium LPS. We determined that catfish respond to E. ictaluri LPS but not to S. Typhimurium LPS. We also determined that E. ictaluri inhibits cytokine production and induces disruption of the intestinal fish epithelia in an O-PS-dependent fashion. The E. ictaluri wild type and ΔwibT LPS mutant caused intestinal tissue damage and inhibited proinflammatory cytokine synthesis, in contrast to E. ictaluri Δgne and Δugd LPS mutants. We concluded that the E. ictaluri O-PS subunits play a major role during pathogenesis, since they influence the recognition of the LPS by the intestinal mucosal immune system of the catfish. The LPS structure of E. ictaluri mutants is needed to understand the mechanism of interaction.
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Foley SL, Johnson TJ, Ricke SC, Nayak R, Danzeisen J. Salmonella pathogenicity and host adaptation in chicken-associated serovars. Microbiol Mol Biol Rev 2013; 77:582-607. [PMID: 24296573 PMCID: PMC3973385 DOI: 10.1128/mmbr.00015-13] [Citation(s) in RCA: 189] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Enteric pathogens such as Salmonella enterica cause significant morbidity and mortality. S. enterica serovars are a diverse group of pathogens that have evolved to survive in a wide range of environments and across multiple hosts. S. enterica serovars such as S. Typhi, S. Dublin, and S. Gallinarum have a restricted host range, in which they are typically associated with one or a few host species, while S. Enteritidis and S. Typhimurium have broad host ranges. This review examines how S. enterica has evolved through adaptation to different host environments, especially as related to the chicken host, and continues to be an important human pathogen. Several factors impact host range, and these include the acquisition of genes via horizontal gene transfer with plasmids, transposons, and phages, which can potentially expand host range, and the loss of genes or their function, which would reduce the range of hosts that the organism can infect. S. Gallinarum, with a limited host range, has a large number of pseudogenes in its genome compared to broader-host-range serovars. S. enterica serovars such as S. Kentucky and S. Heidelberg also often have plasmids that may help them colonize poultry more efficiently. The ability to colonize different hosts also involves interactions with the host's immune system and commensal organisms that are present. Thus, the factors that impact the ability of Salmonella to colonize a particular host species, such as chickens, are complex and multifactorial, involving the host, the pathogen, and extrinsic pressures. It is the interplay of these factors which leads to the differences in host ranges that we observe today.
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Novel determinants of intestinal colonization of Salmonella enterica serotype typhimurium identified in bovine enteric infection. Infect Immun 2013; 81:4311-20. [PMID: 24019407 DOI: 10.1128/iai.00874-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cattle are naturally infected with Salmonella enterica serotype Typhimurium and exhibit pathological features of enteric salmonellosis that closely resemble those in humans. Cattle are the most relevant model of gastrointestinal disease resulting from nontyphoidal Salmonella infection in an animal with an intact microbiota. We utilized this model to screen a library of targeted single-gene deletion mutants to identify novel genes of Salmonella Typhimurium required for survival during enteric infection. Fifty-four candidate mutants were strongly selected, including numerous mutations in genes known to be important for gastrointestinal survival of salmonellae. Three genes with previously unproven phenotypes in gastrointestinal infection were tested in bovine ligated ileal loops. Two of these mutants, STM3602 and STM3846, recapitulated the phenotype observed in the mutant pool. Complementation experiments successfully reversed the observed phenotypes, directly linking these genes to the colonization defects of the corresponding mutant strains. STM3602 encodes a putative transcriptional regulator that may be involved in phosphonate utilization, and STM3846 encodes a retron reverse transcriptase that produces a unique RNA-DNA hybrid molecule called multicopy single-stranded DNA. The genes identified in this study represent an exciting new class of virulence determinants for further mechanistic study to elucidate the strategies employed by Salmonella to survive within the small intestines of cattle.
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Velge P, Wiedemann A, Rosselin M, Abed N, Boumart Z, Chaussé AM, Grépinet O, Namdari F, Roche SM, Rossignol A, Virlogeux-Payant I. Multiplicity of Salmonella entry mechanisms, a new paradigm for Salmonella pathogenesis. Microbiologyopen 2012; 1:243-58. [PMID: 23170225 PMCID: PMC3496970 DOI: 10.1002/mbo3.28] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 05/04/2012] [Accepted: 05/07/2012] [Indexed: 01/27/2023] Open
Abstract
The Salmonella enterica species includes about 2600 diverse serotypes, most of which cause a wide range of food- and water-borne diseases ranging from self-limiting gastroenteritis to typhoid fever in both humans and animals. Moreover, some serotypes are restricted to a few animal species, whereas other serotypes are able to infect plants as well as cold- and warm-blooded animals. An essential feature of the pathogenicity of Salmonella is its capacity to cross a number of barriers requiring invasion of a large variety of phagocytic and nonphagocytic cells. The aim of this review is to describe the different entry pathways used by Salmonella serotypes to enter different nonphagocytic cell types. Until recently, it was accepted that Salmonella invasion of eukaryotic cells required only the type III secretion system (T3SS) encoded by the Salmonella pathogenicity island-1. However, recent evidence shows that Salmonella can cause infection in a T3SS-1-independent manner. Currently, two outer membrane proteins Rck and PagN have been clearly identified as Salmonella invasins. As Rck mediates a Zipper-like entry mechanism, Salmonella is therefore the first bacterium shown to be able to induce both Zipper and Trigger mechanisms to invade host cells. In addition to these known entry pathways, recent data have shown that unknown entry routes could be used according to the serotype, the host and the cell type considered, inducing either Zipper-like or Trigger-like entry processes. The new paradigm presented here should change our classic view of Salmonella pathogenicity. It could also modify our understanding of the mechanisms leading to the different Salmonella-induced diseases and to Salmonella-host specificity.
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Affiliation(s)
- P Velge
- INRA, UMR1282 Infectiologie et Santé Publique F-37380, Nouzilly, France ; Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique F-37000, Tours, France
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Müller AJ, Kaiser P, Dittmar KEJ, Weber TC, Haueter S, Endt K, Songhet P, Zellweger C, Kremer M, Fehling HJ, Hardt WD. Salmonella gut invasion involves TTSS-2-dependent epithelial traversal, basolateral exit, and uptake by epithelium-sampling lamina propria phagocytes. Cell Host Microbe 2012; 11:19-32. [PMID: 22264510 DOI: 10.1016/j.chom.2011.11.013] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 10/03/2011] [Accepted: 11/07/2011] [Indexed: 12/24/2022]
Abstract
Salmonella Typhimurium causes diarrhea by infecting the epithelium and lamina propria of the intestinal mucosa and by secreting various effector proteins through type III secretion systems (TTSSs). However, the mechanisms by which Salmonella transverses the epithelium and is subsequently released into the lamina propria are poorly understood. Using a murine Salmonella-diarrhea model and in vivo microscopy, we show that epithelial traversal requires TTSS-1-mediated invasion and TTSS-2-dependent trafficking to the basolateral side. After being released into the lamina propria, the bacterium is transiently extracellular before being taken up by phagocytes, including CD11c(+)CX(3)CR1(high) monocytic phagocytes (MPs), which were found to constitutively sample cellular material shed from the basolateral side of the epithelium. Thus, Salmonella infects the cecal mucsa through a step-wise process wherein the bacterium transverses the epithelium through TTSS-2-dependent trafficking and then likely exploits lamina propria MPs, which are sampling the epithelium, to enter and replicate within the host.
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Affiliation(s)
- Andreas J Müller
- Institute of Microbiology, D-BIOL, ETH Zürich, 8093 Zürich, Switzerland
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25
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Bifidobacterium infantis 35624 protects against salmonella-induced reductions in digestive enzyme activity in mice by attenuation of the host inflammatory response. Clin Transl Gastroenterol 2012; 3:e15. [PMID: 23238232 PMCID: PMC3367613 DOI: 10.1038/ctg.2012.9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
OBJECTIVES: Salmonella-induced damage to the small intestine may decrease the villi-associated enzyme activity, causing malabsorption of nutrients and diarrhea, and thus contribute to the symptoms of infection. The objective of this study was to determine the mechanism by which different doses and durations of Salmonella infection and lipopolysaccharide (LPS) affect brush border enzyme activity in the mouse, and to determine if the probiotic Bifidobacterium longum subspecies infantis 35624 could attenuate the intestinal damage. METHODS: BALB/c mice were challenged with Salmonella enterica serovar Typhimurium UK1 at various doses (102–108 colony-forming unit (CFU)) and durations (106 CFU for 1–6 days). Mice were also treated with B. longum subsp. infantis 35624 for 2 weeks before and during a 6-day S. Typhimurium challenge (106 CFU), or before injection of LPS. The small intestine was assessed for morphological changes, mRNA expression of cytokines, and activity of the brush border enzymes sucrase–isomaltase, maltase, and alkaline phosphatase. RESULTS: S. Typhimurium infection significantly reduced the activity of all brush border enzymes in a dose- and time-dependent manner (P<0.05). This also occurred following injection of LPS. Pre-treatment with B. longum subsp. infantis 35624 prevented weight loss, protected brush border enzyme activity, reduced the small intestinal damage, and inhibited the increase in interleukin (IL)-10 and IL-8 expression due to Salmonella challenge. CONCLUSIONS: Salmonella infection reduces the small intestinal brush border enzyme activity in mice, with the level of reduction and associated weight loss increasing with dose and duration of infection. B. longum subsp. infantis 35624 treatment attenuated the effect of Salmonella infection on brush border enzyme activity and weight loss, which may be due to modulation of the host immune response.
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Bäumler AJ, Winter SE, Thiennimitr P, Casadesús J. Intestinal and chronic infections: Salmonella lifestyles in hostile environments. ENVIRONMENTAL MICROBIOLOGY REPORTS 2011; 3:508-517. [PMID: 23761329 DOI: 10.1111/j.1758-2229.2011.00242.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The main disease syndromes caused by Salmonella serovars in immunocompetent individuals are gastroenteritis and typhoid fever. These syndromes differ with regard to the host niches in which Salmonella serovars grow and survive to ensure their transmission. During gastroenteritis, non-typhoidal Salmonella serovars such as Salmonella enterica serovar Typhimurium (S. Typhimurium) use their virulence factors to elicit acute intestinal inflammation, thereby creating a novel luminal niche. Reactive oxygen species produced by phagocytes in the intestinal lumen oxidize endogenous sulfur compounds to produce a new respiratory electron acceptor, tetrathionate. Respiration of tetrathionate confers a growth advantage to S. Typhimurium over competing microbes. This growth advantage ensures transmission of the pathogen by the faecal-oral route. In typhoid fever, S. enterica serovar Typhi (S. Typhi) establishes a chronic infection in the gall bladder, and perhaps in additional niches. Studies using the mouse model of typhoid fever suggest that survival and proliferation in the gall bladder may involve several strategies. Invasion of the gallbladder epithelium and formation of biofilms on gallstones may protect the pathogen from the bactericidal activities of bile salts. In the gallbladder lumen, activation of bile defence responses may permit survival of planktonic Salmonella cells. Individuals developing chronic carriage after an episode of typhoid fever can transmit the disease for the remainder of their lives by shedding the pathogen through the cystic duct. Shedding promotes S. Typhi transmission to new susceptible hosts. Here we review Salmonella virulence strategies for growth and survival in host niches that represent reservoirs for transmission.
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Affiliation(s)
- Andreas J Bäumler
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, CA 95616, USA. Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand. Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41080 Sevilla, Spain
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27
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Hallstrom K, McCormick BA. Salmonella Interaction with and Passage through the Intestinal Mucosa: Through the Lens of the Organism. Front Microbiol 2011; 2:88. [PMID: 21747800 PMCID: PMC3128981 DOI: 10.3389/fmicb.2011.00088] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 04/13/2011] [Indexed: 01/13/2023] Open
Abstract
Salmonella enterica serotypes are invasive enteric pathogens spread through fecal contamination of food and water sources, and represent a constant public health threat around the world. The symptoms associated with salmonellosis and typhoid disease are largely due to the host response to invading Salmonella, and to the mechanisms these bacteria employ to survive in the presence of, and invade through the intestinal mucosal epithelia. Surmounting this barrier is required for survival within the host, as well as for further dissemination throughout the body, and subsequent systemic disease. In this review, we highlight some of the major hurdles Salmonella must overcome upon encountering the intestinal mucosal epithelial barrier, and examine how these bacteria surmount and exploit host defense mechanisms.
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Affiliation(s)
- Kelly Hallstrom
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School Worcester, MA, USA
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Radtke AL, Wilson JW, Sarker S, Nickerson CA. Analysis of interactions of Salmonella type three secretion mutants with 3-D intestinal epithelial cells. PLoS One 2010; 5:e15750. [PMID: 21206750 PMCID: PMC3012082 DOI: 10.1371/journal.pone.0015750] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 11/28/2010] [Indexed: 02/07/2023] Open
Abstract
The prevailing paradigm of Salmonella enteropathogenesis based on monolayers asserts that Salmonella pathogenicity island-1 Type Three Secretion System (SPI-1 T3SS) is required for bacterial invasion into intestinal epithelium. However, little is known about the role of SPI-1 in mediating gastrointestinal disease in humans. Recently, SPI-1 deficient nontyphoidal Salmonella strains were isolated from infected humans and animals, indicating that SPI-1 is not required to cause enteropathogenesis and demonstrating the need for more in vivo-like models. Here, we utilized a previously characterized 3-D organotypic model of human intestinal epithelium to elucidate the role of all characterized Salmonella enterica T3SSs. Similar to in vivo reports, the Salmonella SPI-1 T3SS was not required to invade 3-D intestinal cells. Additionally, Salmonella strains carrying single (SPI-1 or SPI-2), double (SPI-1/2) and complete T3SS knockout (SPI-1/SPI-2: flhDC) also invaded 3-D intestinal cells to wildtype levels. Invasion of wildtype and TTSS mutants was a Salmonella active process, whereas non-invasive bacterial strains, bacterial size beads, and heat-killed Salmonella did not invade 3-D cells. Wildtype and T3SS mutants did not preferentially target different cell types identified within the 3-D intestinal aggregates, including M-cells/M-like cells, enterocytes, or Paneth cells. Moreover, each T3SS was necessary for substantial intracellular bacterial replication within 3-D cells. Collectively, these results indicate that T3SSs are dispensable for Salmonella invasion into highly differentiated 3-D models of human intestinal epithelial cells, but are required for intracellular bacterial growth, paralleling in vivo infection observations and demonstrating the utility of these models in predicting in vivo-like pathogenic mechanisms.
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Affiliation(s)
- Andrea L. Radtke
- School of Life Sciences, Center for Infectious Diseases and Vaccinology, The Biodesign Institute at Arizona State University, Tempe, Arizona, United States of America
| | - James W. Wilson
- School of Life Sciences, Center for Infectious Diseases and Vaccinology, The Biodesign Institute at Arizona State University, Tempe, Arizona, United States of America
- Department of Biology, Villanova University, Villanova, Pennsylvania, United States of America
| | - Shameema Sarker
- School of Life Sciences, Center for Infectious Diseases and Vaccinology, The Biodesign Institute at Arizona State University, Tempe, Arizona, United States of America
| | - Cheryl A. Nickerson
- School of Life Sciences, Center for Infectious Diseases and Vaccinology, The Biodesign Institute at Arizona State University, Tempe, Arizona, United States of America
- * E-mail:
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29
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Role of two-component sensory systems of Salmonella enterica serovar Dublin in the pathogenesis of systemic salmonellosis in cattle. Microbiology (Reading) 2010; 156:3108-3122. [DOI: 10.1099/mic.0.041830-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Salmonella enterica serovar Dublin (S. Dublin) is associated with enteritis, typhoid and abortion in cattle. Infections are acquired by the oral route, and the bacteria transit through varied anatomical and cellular niches to elicit systemic disease. S. Dublin must therefore sense and respond to diverse extrinsic stimuli to control gene expression in a spatial and temporal manner. Two-component systems (TCSs) play key roles in such processes, and typically contain a membrane-associated sensor kinase (SK) that modifies a cognate response regulator. Analysis of the genome sequence of S. Dublin identified 31 conserved SK genes. Each SK gene was separately disrupted by lambda Red recombinase-mediated insertion of transposons harbouring unique sequence tags. Calves were challenged with a pool of the mutants together with control strains of defined virulence by the oral and intravenous routes. Quantification of tagged mutants in output pools derived from various tissues and cannulated lymphatic vessels allowed the assignment of spatial roles for each SK following oral inoculation or when the intestinal barrier was bypassed by intravenous delivery. Mutant phenotypes were also assigned in cultured intestinal epithelial cells. Mutants with insertions in barA, envZ, phoQ, ssrA or qseC were significantly negatively selected at all enteric and systemic sites sampled after oral dosing. Mutants lacking baeS, dpiB or citA were negatively selected at some but not all sites. After intravenous inoculation, only barA and phoQ mutants were significantly under-represented at systemic sites. The novel role of baeS in intestinal colonization was confirmed by oral co-infection studies, with a mutant exhibiting modest but significant attenuation at a number of enteric sites. This is the first systematic analysis of the role of all Salmonella TCSs in a highly relevant model of enteric fever. Spatial roles were assigned to eight S. Dublin SKs, but most were not essential for intestinal or systemic infection of the target host.
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Nour-Mohammadzadeh F, Baradaran Seyed Z, Hesaraki S, Yadegari Z, Alidadi N, Sattari Tabrizi S. Septicemic salmonellosis in a two-humped camel calf (Camelus bactrianus). Trop Anim Health Prod 2010; 42:1601-4. [DOI: 10.1007/s11250-010-9626-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2010] [Indexed: 11/24/2022]
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31
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Nunes JS, Lawhon SD, Rossetti CA, Khare S, Figueiredo JF, Gull T, Burghardt RC, Bäumler AJ, Tsolis RM, Andrews-Polymenis HL, Adams LG. Morphologic and cytokine profile characterization of Salmonella enterica serovar typhimurium infection in calves with bovine leukocyte adhesion deficiency. Vet Pathol 2009; 47:322-33. [PMID: 20118318 DOI: 10.1177/0300985809358037] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The role of neutrophils in the pathogenesis of Salmonella enterica Typhimurium-induced ruminant and human enteritis and diarrhea has yet to be characterized with in vivo models. To address this question, the in vivo bovine ligated ileal loop model of nontyphoidal salmonellosis was used in calves with the naturally occurring bovine leukocyte adhesion deficiency (BLAD) mutation whose neutrophils are unable to extravasate and infiltrate the extravascular matrix. Data obtained from 4 BLAD Holstein calves homozygous for BLAD (CD18-), 1 to 5 weeks of age, were compared with 4 controls, age-matched Holstein calves negative for BLAD (CD18+). Morphologic studies revealed that infection of CD18- calves with S Typhimurium resulted in no significant tissue infiltration by neutrophils, less tissue damage, reduced luminal fluid accumulation, and increased bacterial invasion, when compared with CD18+ calves. Ultrastructurally, lesions in enterocytes induced by S Typhimurium infection in CD18- calves--including attachment and disruption of the brush border, apical membrane ruffling formation, and cellular degeneration--were similar to the ones reported in the literature for CD18- calves. Study of cytokine gene expression by quantitative real-time polymerase chain reaction revealed that early stages of acute infection (4-8 hours postinfection) were associated with increased interleukin 8 gene expression in the absence of tissue influx of neutrophils in CD18- calves, whereas later stages of infection (12 hours postinfection) were associated with increased expression of growth-related oncogene alpha in the presence of neutrophil influx in CD18+ calves. In contrast, the proinflammatory cytokines interleukin 1beta and tumor necrosis factor alpha were poorly correlated with the presence or absence of tissue neutrophils.
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Affiliation(s)
- J S Nunes
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, Texas, USA.
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Lim JS, Na HS, Lee HC, Choy HE, Park SC, Han JM, Cho KA. Caveolae-mediated entry of Salmonella typhimurium in a human M-cell model. Biochem Biophys Res Commun 2009; 390:1322-7. [PMID: 19879241 DOI: 10.1016/j.bbrc.2009.10.145] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 10/27/2009] [Indexed: 01/26/2023]
Abstract
Intestinal M cells in Peyer's patches, the specialized antigen-sampling cells of the mucosal immune system, are exploited by Salmonella and other pathogens as a route of invasion. Thus, M cells have attracted lots of attention as a major target of the mucosal immune system. Here, we report that caveolin-1 plays a crucial role in the entry of Salmonella into M cells. We established an in vitro M-like cell model in which polarized enterocyte-like Caco-2 cells created after co-culturing with the Raji B cell line that underwent a phenotypic switch to a form that morphologically and functionally resembles the specialized antigen-transporting M cells. Caveolin-1 was highly expressed in the M-like cells, while not in Caco-2 cells, and a great number of Salmonella infected caveolin-1-expressing M-like cells. To elucidate the role of caveolin-1 in the entry of Salmonella, we downregulated caveolin-1 expression by siRNA and analyzed the level of Salmonella transcytosis across the M-like cells. Transcytosis of Salmonella was markedly reduced by downregulation of caveolin-1 in the M-like cells. These results suggest that caveolin-1 is implicated in the gateway of microbial pathogens through M cells, and, thus, provides a new target of mucosal immunity.
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Affiliation(s)
- Jae Sung Lim
- Department of Biochemistry, Chonnam National University Medical School, 5 Hakdong, Dongku, Gwangju 501-190, Republic of Korea
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Stevens MP, Humphrey TJ, Maskell DJ. Molecular insights into farm animal and zoonotic Salmonella infections. Philos Trans R Soc Lond B Biol Sci 2009; 364:2709-23. [PMID: 19687040 PMCID: PMC2865095 DOI: 10.1098/rstb.2009.0094] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Salmonella enterica is a facultative intracellular pathogen of worldwide importance. Infections may present in a variety of ways, from asymptomatic colonization to inflammatory diarrhoea or typhoid fever depending on serovar- and host-specific factors. Human diarrhoeal infections are frequently acquired via the food chain and farm environment by virtue of the ability of selected non-typhoidal serovars to colonize the intestines of food-producing animals and contaminate the avian reproductive tract and egg. Colonization of reservoir hosts often occurs in the absence of clinical symptoms; however, some S. enterica serovars threaten animal health owing to their ability to cause acute enteritis or translocate from the intestines to other organs causing fever, septicaemia and abortion. Despite the availability of complete genome sequences of isolates representing several serovars, the molecular mechanisms underlying Salmonella colonization, pathogenesis and transmission in reservoir hosts remain ill-defined. Here we review current knowledge of the bacterial factors influencing colonization of food-producing animals by Salmonella and the basis of host range, differential virulence and zoonotic potential.
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Affiliation(s)
- Mark P Stevens
- Division of Microbiology, Institute for Animal Health, Compton, Berkshire RG20 7NN, UK.
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Duerr CU, Zenk SF, Chassin C, Pott J, Gütle D, Hensel M, Hornef MW. O-antigen delays lipopolysaccharide recognition and impairs antibacterial host defense in murine intestinal epithelial cells. PLoS Pathog 2009; 5:e1000567. [PMID: 19730692 PMCID: PMC2729928 DOI: 10.1371/journal.ppat.1000567] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Accepted: 08/05/2009] [Indexed: 12/15/2022] Open
Abstract
Although Toll-like receptor (TLR) 4 signals from the cell surface of myeloid cells, it is restricted to an intracellular compartment and requires ligand internalization in intestinal epithelial cells (IECs). Yet, the functional consequence of cell-type specific receptor localization and uptake-dependent lipopolysaccharide (LPS) recognition is unknown. Here, we demonstrate a strikingly delayed activation of IECs but not macrophages by wildtype Salmonella enterica subsp. enterica sv. (S.) Typhimurium as compared to isogenic O-antigen deficient mutants. Delayed epithelial activation is associated with impaired LPS internalization and retarded TLR4-mediated immune recognition. The O-antigen-mediated evasion from early epithelial innate immune activation significantly enhances intraepithelial bacterial survival in vitro and in vivo following oral challenge. These data identify O-antigen expression as an innate immune evasion mechanism during apical intestinal epithelial invasion and illustrate the importance of early innate immune recognition for efficient host defense against invading Salmonella. The mammalian host recognizes infection by the detection of particular microbial structures. Recognition of these structures leads to activation of host defense effector mechanisms that in turn combat infection. A very potent activating microbial structure is lipopolysaccharide, a cell wall component released by many bacteria such as Salmonella, one of the most frequent causative agents of foodborne infection of the gut. We previously showed that cells lining the gut surface require uptake of bacterial lipopolysaccharide for its detection. The functional consequence of lipopolysaccharide uptake, however, was unknown. Here, we demonstrate that the uptake of lipopolysaccharide released by Salmonella is impaired by its extensive sugar modification. Impaired lipopolysaccharide uptake prevents early activation of host defense mechanisms and thereby allows Salmonella to better survive and proliferate within the host's intestinal cells. Thus, this lipopolysaccharide modification represents a mechanism by which Salmonella impairs recognition by the mammalian host to more efficiently cause infection of the intestinal mucosa.
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Affiliation(s)
- Claudia U. Duerr
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Sebastian F. Zenk
- Institute for Microbiology, University Hospital Erlangen, Erlangen, Germany
| | - Cécilia Chassin
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Johanna Pott
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Dominique Gütle
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Michael Hensel
- Division of Infection Biology, University Hospital Erlangen, Erlangen, Germany
| | - Mathias W. Hornef
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
- * E-mail:
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Accelerated type III secretion system 2-dependent enteropathogenesis by a Salmonella enterica serovar enteritidis PT4/6 strain. Infect Immun 2009; 77:3569-77. [PMID: 19528213 DOI: 10.1128/iai.00511-09] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Salmonella enterica subsp. I serovars Typhimurium and Enteritidis are major causes of enteric disease. The pathomechanism of enteric infection by serovar Typhimurium has been studied in detail. Serovar Typhimurium employs two pathways in parallel for triggering disease, i.e., the "classical" pathway, triggered by type III secretion system 1 (TTSS-1), and the "alternative" pathway, mediated by TTSS-2. It had remained unclear whether these two pathways would also explain the enteropathogenesis of strains from other serovars. We chose the isolate P125109 of the epidemic serovar Enteritidis PT4/6, generated isogenic mutants, and studied their virulence. Using in vitro and in vivo infection experiments, a dendritic cell depletion strategy, and MyD88(-/-) knockout mice, we found that P125109 employs both the "classical" and "alternative" pathways for triggering mucosal inflammation. The "classical" pathway was phenotypically similar in serovar Typhimurium strain SL1344 and in P125109. However, the kinetics of the "alternative" pathway differed significantly. Via TTSS-2, P125109 colonized the gut tissue more efficiently and triggered mucosal inflammation approximately 1 day faster than SL1344 did. In conclusion, our data demonstrate that different Salmonella spp. can differ in their capacity to trigger mucosal inflammation via the "alternative" pathway in vivo.
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TSURUTA T, INOUE R, TSUKAHARA T, MATSUBARA N, HAMASAKI M, USHIDA K. A cell preparation ofEnterococcus faecalisstrain EC-12 stimulates the luminal immunoglobulin A secretion in juvenile calves. Anim Sci J 2009; 80:206-11. [DOI: 10.1111/j.1740-0929.2008.00621.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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37
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Khare S, Nunes JS, Figueiredo JF, Lawhon SD, Rossetti CA, Gull T, Rice-Ficht AC, Adams LG. Early phase morphological lesions and transcriptional responses of bovine ileum infected with Mycobacterium avium subsp. paratuberculosis. Vet Pathol 2009; 46:717-28. [PMID: 19276052 DOI: 10.1354/vp.08-vp-0187-g-fl] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of chronic enteritis in ruminants (Johne's disease) and a possible etiopathologic agent in human Crohn's disease. The host-pathogen interaction in this chronic disease has largely depended on the randomly collected static lesions studied in subclinically or clinically infected animals. We have established and utilized the neonatal calf ligated ileal loop model to study the early temporal host changes during MAP infection. After inoculation of ligated ileal loop with MAP, samples were analyzed for bacterial invasion, histologic and ultrastructural morphologic changes, and gene expression at several times (0.5-12 hours) postinfection. Our results indicate that MAP invades the intestinal mucosa as early as 0.5 hour postinoculation. Distribution and migration of neutrophils, monocytes/macrophages, and goblet cells were confirmed by histopathology, scanning and transmission electron microscopy. Coincident with the morphologic analysis, we measured by real-time polymerase chain reaction gene expression of various cytokines/chemokines that are involved in the recruitment of mononuclear and polymorphonuclear leukocytes to the site of infection. We also detected expression of several other genes, including intestinal-trefoil factor, profilin, lactoferrin, and enteric ss-defensin, which may play significant roles in the early MAP infection. Thus, the calf ligated intestinal loop model may be used as a human disease model to understand the role of MAP in the pathogenesis of Crohn's disease.
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Affiliation(s)
- S Khare
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Veterinary Research Building, Bldg. 1197, Room 141, Texas A&M University, College Station, TX 77843-4467, USA
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38
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Cerovic V, McDonald V, Nassar MA, Paulin SM, Macpherson GG, Milling SWF. New insights into the roles of dendritic cells in intestinal immunity and tolerance. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 272:33-105. [PMID: 19121816 DOI: 10.1016/s1937-6448(08)01602-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Dendritic cells (DCs) play a critical key role in the initiation of immune responses to pathogens. Paradoxically, they also prevent potentially damaging immune responses being directed against the multitude of harmless antigens, to which the body is exposed daily. These roles are particularly important in the intestine, where only a single layer of epithelial cells provides a barrier against billions of commensal microorganisms, pathogens, and food antigens, over a huge surface area. In the intestine, therefore, DCs are required to perform their dual roles very efficiently to protect the body from the dual threats of invading pathogens and unwanted inflammatory reactions. In this review, we first describe the biology of DCs and their interactions with other cells types, paying particular attention to intestinal DCs. We, then, examine the ways in which this biology may become misdirected, resulting in inflammatory bowel disease. Finally, we discuss how DCs potentiate immune responses against viral, bacterial, parasitic infections, and their importance in the pathogenesis of prion diseases. We, therefore, provide an overview of the complex cellular interactions that affect intestinal DCs and control the balance between immunity and tolerance.
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Affiliation(s)
- Vuk Cerovic
- Sir William Dunn School of Pathology, Oxford University, Oxford, United Kingdom
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Martinez-Argudo I, Jepson MA. Salmonella translocates across an in vitro M cell model independently of SPI-1 and SPI-2. MICROBIOLOGY-SGM 2009; 154:3887-3894. [PMID: 19047755 DOI: 10.1099/mic.0.2008/021162-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We have used an in vitro model of intestinal M cells to examine the mechanisms by which Salmonella enterica translocates across these specialized cells, which constitute a primary site of infection of the mammalian host. S. enterica can invade cultured cells by deploying a type III secretion system (TTSS) encoded within Salmonella pathogenicity island 1 (SPI-1) to translocate effector proteins into the host cell cytoplasm that trigger cellular responses, including prominent cytoskeletal rearrangements. After Salmonella enters the host cell, a second TTSS encoded in SPI-2 modulates intracellular trafficking and enables the bacteria to replicate within a modified vacuolar compartment. Within the host intestine, specialized antigen-sampling M cells, which reside in the epithelium overlying lymphoid tissues in the gut, are a preferential site of Salmonella invasion. The mechanisms of infection of M cells remain poorly defined and it is not known whether either SPI-1 or SPI-2 is required for infection of these cells. To address these questions we have employed an in vitro M cell model involving co-culture of polarized Caco-2 intestinal epithelial cells with Raji B cells. S. enterica serovar Typhimurium translocated across Caco-2/Raji co-cultures to a much greater extent than they cross native Caco-2 cell monolayers. Salmonella translocation was greatly reduced by heat treatment or fixation, suggesting that processes distinct from the sampling of inert particles are the main determinants of bacterial translocation. Translocation across both mono-cultured and co-cultured Caco-2 cells was partially inhibited by treatment with the dynamin inhibitor dynasore, but resistant to EIPA, an inhibitor of macropinocytosis. There was no difference between the abilities of wild-type Salmonella Typhimurium and mutants lacking multiple SPI-1 effectors to translocate across the M cell model, although the SPI-1 effector mutants were somewhat attenuated for translocation across native Caco-2 layers. There was also no difference between wild-type and SPI-2 mutants in M cell translocation. Together these data suggest that that SPI-1 and SPI-2 are dispensable for rapid M cell translocation and that infection at these specialized epithelial sites involves distinctive mechanisms that are not reliably modelled using conventional cell culture infection models.
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Affiliation(s)
- Isabel Martinez-Argudo
- Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Mark A Jepson
- Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK
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40
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Interleukin-23 orchestrates mucosal responses to Salmonella enterica serotype Typhimurium in the intestine. Infect Immun 2008; 77:387-98. [PMID: 18955477 DOI: 10.1128/iai.00933-08] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Salmonella enterica serotype Typhimurium causes an acute inflammatory reaction in the ceca of streptomycin-pretreated mice that involves T-cell-dependent induction of gamma interferon (IFN-gamma), interleukin-22 (IL-22), and IL-17 expression (genes Ifn-gamma, Il-22, and Il-17, respectively). We investigated here the role of IL-23 in initiating these inflammatory responses using the streptomycin-pretreated mouse model. Compared to wild-type mice, the expression of IL-17 was abrogated, IL-22 expression was markedly reduced, but IFN-gamma expression was normal in the ceca of IL-23p19-deficient mice during serotype Typhimurium infection. IL-23p19-deficient mice also exhibited a markedly reduced expression of regenerating islet-derived 3 gamma, keratinocyte-derived cytokine, and reduced neutrophil recruitment into the cecal mucosa during infection. Analysis of CD3(+) lymphocytes in the intestinal mucosa by flow cytometry revealed that alphabeta T cells were the predominant cell type expressing the IL-23 receptor in naive mice. However, a marked increase in the number of IL-23 receptor-expressing gammadelta T cells was observed in the lamina propria during serotype Typhimurium infection. Compared to wild-type mice, gammadelta T-cell-receptor-deficient mice exhibited blunted expression of IL-17 during serotype Typhimurium infection, while IFN-gamma expression was normal. These data suggested that gammadelta T cells are a significant source, but not the sole source, of IL-17 in the acutely inflamed cecal mucosa of mice. Collectively, our results point to IL-23 as an important player in initiating a T-cell-dependent amplification of inflammatory responses in the intestinal mucosa during serotype Typhimurium infection.
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41
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Egan S, Lanigan M, Shiell B, Beddome G, Stewart D, Vaughan J, Michalski WP. The recovery of Mycobacterium avium subspecies paratuberculosis from the intestine of infected ruminants for proteomic evaluation. J Microbiol Methods 2008; 75:29-39. [PMID: 18547663 DOI: 10.1016/j.mimet.2008.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 04/24/2008] [Accepted: 04/28/2008] [Indexed: 10/22/2022]
Abstract
Johne's disease is a slowly developing intestinal disease, primarily of ruminants, caused by Mycobacterium avium subspecies paratuberculosis. The disease contributes to significant economic losses worldwide in agricultural industry. Analysis of bacterial proteomes isolated directly from infected animals can provide important information about the repertoire of proteins present during infection and disease progression. In this study, M. avium subspecies paratuberculosis has been extracted from Johne's disease-infected cattle and goat intestinal tissue sections in a manner compatible with direct 2-DE proteomic analysis for comparison with in vitro-cultured bacteria. M. avium subspecies paratuberculosis was harvested from the submucosa and mucosa of intestinal sections and enriched from macerated tissue by hypotonic lysis, sonication and centrifugation through a viscosity gradient. Subsequent comparison of the proteomes of the in vivo- and in vitro-derived bacteria identified a number of proteins that were differentially expressed. Among them, a number of hypothetical proteins of unknown function and a hypothetical fatty acyl dehydrogenase (FadE3_2) and 3-hydroxyacyl-CoA dehydrogenase, possibly important for in vivo metabolism, utilising the pathway for the beta-oxidation of fatty acids.
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Affiliation(s)
- Sharon Egan
- Protein Biochemistry and Proteomics Group, Australian Animal Health Laboratory, CSIRO Livestock Industries, Geelong VIC 3220, Australia
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42
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Silva D, Silva P, Fagliari J, Ávila F, Alessi A, Oliveira R. Avaliação clínica da infecção experimental de bezerros com Salmonella Dublin. ARQ BRAS MED VET ZOO 2008. [DOI: 10.1590/s0102-09352008000100034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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43
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Hautefort I, Thompson A, Eriksson-Ygberg S, Parker ML, Lucchini S, Danino V, Bongaerts RJM, Ahmad N, Rhen M, Hinton JCD. During infection of epithelial cells Salmonella enterica serovar Typhimurium undergoes a time-dependent transcriptional adaptation that results in simultaneous expression of three type 3 secretion systems. Cell Microbiol 2007; 10:958-84. [PMID: 18031307 PMCID: PMC2343689 DOI: 10.1111/j.1462-5822.2007.01099.x] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The biogenesis of the Salmonella-containing vacuole within mammalian cells has been intensively studied over recent years. However, the ability of Salmonella to sense and adapt to the intracellular environment of different types of host cells has received much less attention. To address this issue, we report the transcriptome of Salmonella enterica serovar Typhimurium SL1344 within epithelial cells and show comparisons with Salmonella gene expression inside macrophages. We report that S. Typhimurium expresses a characteristic intracellular transcriptomic signature in response to the environments it encounters within different cell types. The signature involves the upregulation of the mgtBC, pstACS and iro genes for magnesium, phosphate and iron uptake, and Salmonella pathogenicity island 2 (SPI2). Surprisingly, in addition to SPI2, the invasion-associated SPI1 pathogenicity island and the genes involved in flagellar biosynthesis were expressed inside epithelial cells at later stages of the infection, while they were constantly downregulated in macrophage-like cells. To our knowledge, this is the first report of the simultaneous transcription of all three Type Three Secretion Systems (T3SS) within an intracellular Salmonella population. We discovered that S. Typhimurium strain SL1344 was strongly cytotoxic to epithelial cells after 6 h of infection and hypothesize that the time-dependent changes in Salmonella gene expression within epithelial cells reflects the bacterial response to host cells that have been injured by the infection process.
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Affiliation(s)
- I Hautefort
- Molecular Microbiology Group, Institute of Food Research, Norwich NR4 7UA, UK.
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44
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Pullinger GD, Paulin SM, Charleston B, Watson PR, Bowen AJ, Dziva F, Morgan E, Villarreal-Ramos B, Wallis TS, Stevens MP. Systemic translocation of Salmonella enterica serovar Dublin in cattle occurs predominantly via efferent lymphatics in a cell-free niche and requires type III secretion system 1 (T3SS-1) but not T3SS-2. Infect Immun 2007; 75:5191-9. [PMID: 17724072 PMCID: PMC2168298 DOI: 10.1128/iai.00784-07] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Revised: 07/13/2007] [Accepted: 08/14/2007] [Indexed: 12/31/2022] Open
Abstract
Salmonella enterica is an important diarrheal pathogen, and infections may involve severe systemic sequelae depending on serovar- and host-specific factors. The molecular mechanisms underlying translocation of host-restricted and -specific serovars of S. enterica from the intestines to distal organs are ill defined. By surgical cannulation of lymph and blood vessels draining the distal ileum in cattle, S. enterica serovar Dublin was observed to translocate predominantly via mesenteric lymph nodes to efferent lymphatics in a manner that correlates with systemic virulence, since the fowl typhoid-associated serovar Gallinarum translocated at a significantly lower level. While both S. enterica serovars Dublin and Gallinarum were intracellular while in the intestinal mucosa and associated with major histocompatibility complex class II-positive cells, the bacteria were predominantly extracellular within efferent lymph. Screening of a library of signature-tagged serovar Dublin mutants following oral inoculation of calves defined the role of 36 virulence-associated loci in enteric and systemic phases of infection. The number and proportion of tagged clones reaching the liver and spleen early after oral infection were identical to the values in efferent lymph, implying that this may be a relevant mode of dissemination. Coinfection studies confirmed that lymphatic translocation requires the function of type III secretion system 1 (T3SS-1) but, remarkably, not T3SS-2. This is the first description of the mode and genetics of systemic translocation of serovar Dublin in its natural host.
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Affiliation(s)
- Gillian D Pullinger
- Division of Microbiology, Institute for Animal Health, Compton, Berkshire RG20 7NN, United Kingdom
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45
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Raffatellu M, Santos RL, Chessa D, Wilson RP, Winter SE, Rossetti CA, Lawhon SD, Chu H, Lau T, Bevins CL, Adams LG, Bäumler AJ. The capsule encoding the viaB locus reduces interleukin-17 expression and mucosal innate responses in the bovine intestinal mucosa during infection with Salmonella enterica serotype Typhi. Infect Immun 2007; 75:4342-50. [PMID: 17591794 PMCID: PMC1951168 DOI: 10.1128/iai.01571-06] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The viaB locus contains genes for the biosynthesis and export of the Vi capsular antigen of Salmonella enterica serotype Typhi. Wild-type serotype Typhi induces less CXC chemokine production in tissue culture models than does an isogenic viaB mutant. Here we investigated the in vivo relevance of these observations by determining whether the presence of the viaB region prevents inflammation in two animal models of gastroenteritis. Unlike S. enterica serotype Typhimurium, serotype Typhi or a serotype Typhi viaB mutant did not elicit marked inflammatory changes in the streptomycin-pretreated mouse model. In contrast, infection of bovine ligated ileal loops with a serotype Typhi viaB mutant resulted in more fluid accumulation and higher expression of the chemokine growth-related oncogene alpha (GROalpha) and interleukin-17 (IL-17) than did infection with the serotype Typhi wild type. There was a marked upregulation of IL-17 expression in both the bovine ligated ileal loop model and the streptomycin-pretreated mouse model, suggesting that this cytokine is an important component of the inflammatory response to infection with Salmonella serotypes. Introduction of the cloned viaB region into serotype Typhimurium resulted in a significant reduction of GROalpha and IL-17 expression and in reduced fluid secretion. Our data support the idea that the viaB region plays a role in reducing intestinal inflammation in vivo.
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MESH Headings
- Animals
- Antigens, Bacterial/genetics
- Antigens, Bacterial/physiology
- Bacterial Capsules/biosynthesis
- Bacterial Capsules/genetics
- Bacterial Capsules/immunology
- Cattle
- Cell Movement/genetics
- Cell Movement/immunology
- Disease Models, Animal
- Down-Regulation/genetics
- Down-Regulation/immunology
- Genetic Markers
- Immunity, Mucosal/genetics
- Inflammation Mediators/metabolism
- Inflammation Mediators/physiology
- Interleukin-17/antagonists & inhibitors
- Interleukin-17/biosynthesis
- Interleukin-17/genetics
- Intestinal Mucosa/immunology
- Intestinal Mucosa/microbiology
- Intestinal Mucosa/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Neutrophils/immunology
- Neutrophils/microbiology
- Neutrophils/pathology
- Operon/genetics
- Polysaccharides, Bacterial/genetics
- Polysaccharides, Bacterial/physiology
- Salmonella Infections, Animal/immunology
- Salmonella Infections, Animal/pathology
- Salmonella Infections, Animal/prevention & control
- Salmonella typhi/genetics
- Salmonella typhi/immunology
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Affiliation(s)
- Manuela Raffatellu
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Ave., Davis, CA 95616-8645, USA
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46
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Rodenburg W, Bovee-Oudenhoven IMJ, Kramer E, van der Meer R, Keijer J. Gene expression response of the rat small intestine following oral Salmonella infection. Physiol Genomics 2007; 30:123-33. [PMID: 17374845 DOI: 10.1152/physiolgenomics.00190.2006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Data on the molecular response of the intestine to the food-borne pathogen Salmonella are derived from in vitro studies, whereas in vivo data are lacking. We performed an oral S. enteritidis infection study in Wistar rats to obtain insight in the in vivo response in time. Expression profiles of ileal mucosa (IM) and Peyer's patches (PP) were generated using DNA microarrays at days 1, 3, and 6 postinfection. An overview of Salmonella-regulated processes was obtained and confirmed by quantitative real-time PCR on pooled and individual samples. Salmonella-induced gene expression responses in vivo are fewer and smaller than observed in vitro, and the response develops over a longer period of time. Few effects are seen at day 1 and mainly occur in IM, suggesting the mucosa as the primary site of invasion. Later, a bigger response is observed, especially in PP. Decreased expression of anti-microbial peptides genes (in IM at day 1) suggests inhibition of this process by Salmonella. Newly identified target processes are carbohydrate transport (increased expression in IM at day 1) and phase I and phase II detoxification (decreased expression at days 3 and 6). Increase of cytokine and chemokine expression occurs at later time points, both in PP and IM. Pancreatitis-associated protein, lipocalin 2, and calprotectin, potential inflammatory marker proteins, showed induced expression from day 3 onward. We conclude that the in vivo gene expression response of the ileum to Salmonella differs to a large extent from the response seen in vitro.
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47
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Abstract
The gastrointestinal tract represents the largest mucosal membrane surface in the human body. The immune system in the gut is the first line of host defense against mucosal microbial pathogens and it plays a crucial role in maintaining mucosal homeostasis. Membranous or microfold cells, commonly referred to as microfold cells, are specialized epithelial cells of the gut-associated lymphoid tissues (GALT) and they play a sentinel role for the intestinal immune system by delivering luminal antigens through the follicle-associated epithelium to the underlying immune cells. M cells sample and uptake antigens at their apical membrane, encase them in vesicles to transport them to the basolateral membrane of M cells, and from there deliver antigens to the nearby lymphocytes. On the flip side, some intestinal pathogens exploit M cells as their portal of entry to invade the host and cause infections. In this article, we briefly review our current knowledge on the morphology, development, and function of M cells, with an emphasis on their dual role in the pathogenesis of gut infection and in the development of host mucosal immunity.
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48
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Dvorak CMT, Hirsch GN, Hyland KA, Hendrickson JA, Thompson BS, Rutherford MS, Murtaugh MP. Genomic dissection of mucosal immunobiology in the porcine small intestine. Physiol Genomics 2006; 28:5-14. [PMID: 16940429 DOI: 10.1152/physiolgenomics.00104.2006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The enteric immune system of swine protects against infectious and noninfectious environmental insults and discriminates ingested nutrients, food, and commensal microflora from pathogenic agents. The molecular and cellular elements of the immune system have been selected over evolutionary time in response to the specific environment of pigs. Thus, models of immune function based on mouse and human need to be applied cautiously in the pig. To better understand how the mucosal immune system of the small intestine accomplishes the conflicting functions of food tolerance and immunity to enteric infection, we used a genomic approach to profile gene expression in the Peyer's patch. More than 40% of mRNA enriched by differential subtraction for Peyer's patch-specific expressed sequences represented genes of unknown function or had no match in GenBank. Microarray analysis and radiation hybrid mapping validated their porcine origin and provided additional insights into putative functions. The abundance of expressed genes of unknown function indicates that a substantial fraction of the immunological and physiological processes of the Peyer's patch remains to be discovered. It further suggests that swine have evolved specialized biochemical and immunological processes in the small intestine. Further elucidation of these processes are expected to provide novel insights into swine enteric mucosal immune function.
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Affiliation(s)
- Cheryl M T Dvorak
- Department of Veterinary & Biomedical Sciences, University of Minnesota, St. Paul, Minnesota 55108, USA
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49
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Soni J, Baird AW, O'Brien LM, McElroy M, Callanan JJ, Bassett HF, Campion D, Brayden DJ. Rat, ovine and bovine Peyer's patches mounted in horizontal diffusion chambers display sampling function. J Control Release 2006; 115:68-77. [PMID: 16884804 DOI: 10.1016/j.jconrel.2006.06.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 06/19/2006] [Accepted: 06/22/2006] [Indexed: 12/19/2022]
Abstract
Freshly excised rat, ovine and bovine ileal Peyer's patch (PP) and non-Peyer's patch tissues (NPP) were mounted in modified horizontal polyethylene diffusion chambers with a range of window areas. Rat tissue was initially used to establish that barrier function and histology were maintained for up to 60 min. Horse-radish peroxidase (HRP) fluxes and S. Typhimurium adherence and invasion were significantly higher in rat PP over NPP. Particle uptake was shown to be a rapid, energy-, time-, and size-dependent process, occurring more readily in PP than NPP tissue in each species. In a kinetic analysis, particles were localized initially in the follicle-associated epithelium and then in the dome region. For NPP uptake, particles were initially localized to villous epithelium, and were then detected in the crypts and lamina propria. Electrophysiological parameters including pharmacologically-stimulated inward short-circuit current responses were determined in isolated PP and NPP from each species mounted under identical conditions in Ussing chambers. In conclusion, comparative functional and histological characteristics of PP from several species were demonstrated in horizontal diffusion chambers. Horizontal diffusion chambers are therefore a useful in vitro model in which a range of functions including transport of particulate formulations by PP may be examined.
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Affiliation(s)
- Jyoti Soni
- School of Agriculture, Food Science and Veterinary Medicine and Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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50
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Tükel C, Raffatellu M, Chessa D, Wilson RP, Akçelik M, Bäumler AJ. Neutrophil influx during non-typhoidal salmonellosis: who is in the driver's seat? ACTA ACUST UNITED AC 2006; 46:320-9. [PMID: 16553804 DOI: 10.1111/j.1574-695x.2006.00051.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A massive neutrophil influx in the intestine is the histopathological hallmark of Salmonella enterica serovar Typhimurium-induced enterocolitis in humans. Two major hypotheses on the mechanism leading to neutrophil infiltration in the intestinal mucosa have emerged. One hypothesis suggests that S. enterica serovar Typhimurium takes an active role in triggering this host response by injecting proteins, termed effectors, into the host cell cytosol which induce a proinflammatory gene expression profile in the intestinal epithelium. The second hypothesis suggests a more passive role for the pathogen by proposing that bacterial invasion stimulates the innate pathways of inflammation because the pathogen-associated molecular patterns of S. enterica serovar Typhimurium are recognized by pathogen recognition receptors on cells in the lamina propria. A review of the current literature reveals that, while pathogen recognition receptors are clearly involved in eliciting neutrophil influx during S. enterica serovar Typhimurium infection, a direct contribution of effectors in triggering proinflammatory host cell responses cannot currently be ruled out.
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Affiliation(s)
- Cagla Tükel
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, Davis, CA 95616-8645, USA
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