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Amemiya K, Dankmeyer JL, Bernhards RC, Fetterer DP, Waag DM, Worsham PL, DeShazer D. Activation of Toll-Like Receptors by Live Gram-Negative Bacterial Pathogens Reveals Mitigation of TLR4 Responses and Activation of TLR5 by Flagella. Front Cell Infect Microbiol 2021; 11:745325. [PMID: 34888257 PMCID: PMC8650638 DOI: 10.3389/fcimb.2021.745325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/18/2021] [Indexed: 12/27/2022] Open
Abstract
Successful bacterial pathogens have evolved to avoid activating an innate immune system in the host that responds to the pathogen through distinct Toll-like receptors (TLRs). The general class of biochemical components that activate TLRs has been studied extensively, but less is known about how TLRs interact with the class of compounds that are still associated with the live pathogen. Accordingly, we examined the activation of surface assembled TLR 2, 4, and 5 with live Tier 1 Gram-negative pathogens that included Yersinia pestis (plague), Burkholderia mallei (glanders), Burkholderia pseudomallei (melioidosis), and Francisella tularensis (tularemia). We found that Y. pestis CO92 grown at 28°C activated TLR2 and TLR4, but at 37°C the pathogen activated primarily TLR2. Although B. mallei and B. pseudomallei are genetically related, the former microorganism activated predominately TLR4, while the latter activated predominately TLR2. The capsule of wild-type B. pseudomallei 1026b was found to mitigate the activation of TLR2 and TLR4 when compared to a capsule mutant. Live F. tularensis (Ft) Schu S4 did not activate TLR2 or 4, although the less virulent Ft LVS and F. novicida activated only TLR2. B. pseudomallei purified flagellin or flagella attached to the microorganism activated TLR5. Activation of TLR5 was abolished by an antibody to TLR5, or a mutation of fliC, or elimination of the pathogen by filtration. In conclusion, we have uncovered new properties of the Gram-negative pathogens, and their interaction with TLRs of the host. Further studies are needed to include other microorganism to extend our observations with their interaction with TLRs, and to the possibility of leading to new efforts in therapeutics against these pathogens.
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Affiliation(s)
- Kei Amemiya
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, United States
| | - Jennifer L Dankmeyer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, United States
| | - Robert C Bernhards
- Edgewood Chemical Biological Centre, Aberdeen Proving Ground, Edgewood, MD, United States
| | - David P Fetterer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, United States
| | - David M Waag
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, United States
| | - Patricia L Worsham
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, United States
| | - David DeShazer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, United States
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Lin YJ, Flaczyk A, Wolfheimer S, Goretzki A, Jamin A, Wangorsch A, Vieths S, Scheurer S, Schülke S. The Fusion Protein rFlaA:Betv1 Modulates DC Responses by a p38-MAPK and COX2-Dependent Secretion of PGE 2 from Epithelial Cells. Cells 2021; 10:3415. [PMID: 34943923 PMCID: PMC8700022 DOI: 10.3390/cells10123415] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/26/2021] [Accepted: 12/02/2021] [Indexed: 11/16/2022] Open
Abstract
Developing new adjuvants/vaccines and better understanding their mode-of-action is an important task. To specifically improve birch pollen allergy treatment, we designed a fusion protein consisting of major birch pollen allergen Betv1 conjugated to the TLR5-ligand flagellin (rFlaA:Betv1). This study investigates the immune-modulatory effects of rFlaA:Betv1 on airway epithelial cells. LA-4 mouse lung epithelial cells were stimulated with rFlaA:Betv1 in the presence/absence of various inhibitors with cytokine- and chemokine secretion quantified by ELISA and activation of intracellular signaling cascades demonstrated by Western blot (WB). Either LA-4 cells or LA-4-derived supernatants were co-cultured with BALB/c bone marrow-derived myeloid dendritic cells (mDCs). Compared to equimolar amounts of flagellin and Betv1 provided as a mixture, rFlaA:Betv1 induced higher secretion of IL-6 and the chemokines CCL2 and CCL20 from LA-4 cells and a pronounced MAPK- and NFκB-activation. Mechanistically, rFlaA:Betv1 was taken up more strongly and the induced cytokine production was inhibited by NFκB-inhibitors, while ERK- and p38-MAPK-inhibitors only suppressed IL-6 and CCL2 secretion. In co-cultures of LA-4 cells with mDCs, rFlaA:Betv1-stimulated LA-4 cells p38-MAPK- and COX2-dependently secreted PGE2, which modulated DC responses by suppressing pro-inflammatory IL-12 and TNF-α secretion. Taken together, these results contribute to our understanding of the mechanisms underlying the strong immune-modulatory effects of flagellin-containing fusion proteins.
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Affiliation(s)
- Yen-Ju Lin
- Molecular Allergology, Paul-Ehrlich-Institut, 63225 Langen, Germany; (Y.-J.L.); (A.F.); (S.W.); (A.G.); (A.J.); (A.W.); (S.V.); (S.S.)
| | - Adam Flaczyk
- Molecular Allergology, Paul-Ehrlich-Institut, 63225 Langen, Germany; (Y.-J.L.); (A.F.); (S.W.); (A.G.); (A.J.); (A.W.); (S.V.); (S.S.)
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Sonja Wolfheimer
- Molecular Allergology, Paul-Ehrlich-Institut, 63225 Langen, Germany; (Y.-J.L.); (A.F.); (S.W.); (A.G.); (A.J.); (A.W.); (S.V.); (S.S.)
| | - Alexandra Goretzki
- Molecular Allergology, Paul-Ehrlich-Institut, 63225 Langen, Germany; (Y.-J.L.); (A.F.); (S.W.); (A.G.); (A.J.); (A.W.); (S.V.); (S.S.)
| | - Annette Jamin
- Molecular Allergology, Paul-Ehrlich-Institut, 63225 Langen, Germany; (Y.-J.L.); (A.F.); (S.W.); (A.G.); (A.J.); (A.W.); (S.V.); (S.S.)
| | - Andrea Wangorsch
- Molecular Allergology, Paul-Ehrlich-Institut, 63225 Langen, Germany; (Y.-J.L.); (A.F.); (S.W.); (A.G.); (A.J.); (A.W.); (S.V.); (S.S.)
| | - Stefan Vieths
- Molecular Allergology, Paul-Ehrlich-Institut, 63225 Langen, Germany; (Y.-J.L.); (A.F.); (S.W.); (A.G.); (A.J.); (A.W.); (S.V.); (S.S.)
| | - Stephan Scheurer
- Molecular Allergology, Paul-Ehrlich-Institut, 63225 Langen, Germany; (Y.-J.L.); (A.F.); (S.W.); (A.G.); (A.J.); (A.W.); (S.V.); (S.S.)
| | - Stefan Schülke
- Molecular Allergology, Paul-Ehrlich-Institut, 63225 Langen, Germany; (Y.-J.L.); (A.F.); (S.W.); (A.G.); (A.J.); (A.W.); (S.V.); (S.S.)
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53
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Cheok YY, Lee CYQ, Cheong HC, Vadivelu J, Looi CY, Abdullah S, Wong WF. An Overview of Helicobacter pylori Survival Tactics in the Hostile Human Stomach Environment. Microorganisms 2021; 9:microorganisms9122502. [PMID: 34946105 PMCID: PMC8705132 DOI: 10.3390/microorganisms9122502] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 11/28/2021] [Accepted: 11/29/2021] [Indexed: 12/17/2022] Open
Abstract
Helicobacter pylori is well established as a causative agent for gastritis, peptic ulcer, and gastric cancer. Armed with various inimitable virulence factors, this Gram-negative bacterium is one of few microorganisms that is capable of circumventing the harsh environment of the stomach. The unique spiral structure, flagella, and outer membrane proteins accelerate H. pylori movement within the viscous gastric mucosal layers while facilitating its attachment to the epithelial cells. Furthermore, secretion of urease from H. pylori eases the acidic pH within the stomach, thus creating a niche for bacteria survival and replication. Upon gaining a foothold in the gastric epithelial lining, bacterial protein CagA is injected into host cells through a type IV secretion system (T4SS), which together with VacA, damage the gastric epithelial cells. H. pylori does not only establishes colonization in the stomach, but also manipulates the host immune system to permit long-term persistence. Prolonged H. pylori infection causes chronic inflammation that precedes gastric cancer. The current review provides a brief outlook on H. pylori survival tactics, bacterial-host interaction and their importance in therapeutic intervention as well as vaccine development.
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Affiliation(s)
- Yi Ying Cheok
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (Y.Y.C.); (C.Y.Q.L.); (H.C.C.); (J.V.)
| | - Chalystha Yie Qin Lee
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (Y.Y.C.); (C.Y.Q.L.); (H.C.C.); (J.V.)
| | - Heng Choon Cheong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (Y.Y.C.); (C.Y.Q.L.); (H.C.C.); (J.V.)
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (Y.Y.C.); (C.Y.Q.L.); (H.C.C.); (J.V.)
| | - Chung Yeng Looi
- School of Biosciences, Faculty of Health & Medical Sciences, Taylor’s University, Subang Jaya 47500, Malaysia;
| | - Suhailah Abdullah
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia;
| | - Won Fen Wong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (Y.Y.C.); (C.Y.Q.L.); (H.C.C.); (J.V.)
- Correspondence:
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Macrophages in Microbial Pathogenesis: Commonalities of Defense Evasion Mechanisms. Infect Immun 2021; 90:e0029121. [PMID: 34780281 DOI: 10.1128/iai.00291-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Macrophages are key arsenals of the immune system against invaders. After compartmental isolation of a pathogen in phagosomes, the host immune response attempts to neutralize the pathogen. However, pathogens possess the ability to subvert these assaults and can also convert macrophages into their replicative niche. The multiple host defense evasion mechanisms employed by these pathogens like phagosome maturation arrest, molecular mimicry through secretory antigens, interference with host signaling, active radical neutralization, inhibition of phagosome acidification, alteration of programmed cell death and many other mechanisms. Macrophage biology as a part of the host-pathogen interaction has expanded rapidly in the past decade. The present review aims to shed some light upon the macrophage defense evasion strategies employed by infecting pathogens. We have also incorporated recent knowledge in the field of macrophage dynamics during infection and evolutionary perspectives of macrophage dynamics.
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55
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Undercover Agents of Infection: The Stealth Strategies of T4SS-Equipped Bacterial Pathogens. Toxins (Basel) 2021; 13:toxins13100713. [PMID: 34679006 PMCID: PMC8539587 DOI: 10.3390/toxins13100713] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 10/04/2021] [Accepted: 10/06/2021] [Indexed: 11/16/2022] Open
Abstract
Intracellular bacterial pathogens establish their replicative niches within membrane-encompassed compartments, called vacuoles. A subset of these bacteria uses a nanochannel called the type 4 secretion system (T4SS) to inject effector proteins that subvert the host cell machinery and drive the biogenesis of these compartments. These bacteria have also developed sophisticated ways of altering the innate immune sensing and response of their host cells, which allow them to cause long-lasting infections and chronic diseases. This review covers the mechanisms employed by intravacuolar pathogens to escape innate immune sensing and how Type 4-secreted bacterial effectors manipulate host cell mechanisms to allow the persistence of bacteria.
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56
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Gonzalez I, Araya P, Schneider I, Lindner C, Rojas A. Pattern recognition receptors and their roles in the host response to Helicobacter pylori infection. Future Microbiol 2021; 16:1229-1238. [PMID: 34615380 DOI: 10.2217/fmb-2021-0106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Helicobacter pylori (H. pylori) infection is highly prevalent, affecting 4.4 billion people globally. This pathogen is a risk factor in the pathogenesis of more than 75% of worldwide cases of gastric cancer. Pattern recognition receptors are essential in the innate immune response to H. pylori infection. They recognize conserved pathogen structures and myriad alarmins released by host cells in response to microbial components, cytokines or cellular stress, thus triggering a robust proinflammatory response, which is crucial in H. pylori-induced gastric carcinogenesis. In this review, we intend to highlight the main pattern recognition receptors involved in the recognition and host response to H. pylori, as well as the main structures recognized and the subsequent inflammatory response.
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Affiliation(s)
- Ileana Gonzalez
- Biomedical Research Labs, Medicine Faculty, Catholic University of Maule, Talca, 3460000, Chile
| | - Paulina Araya
- Biomedical Research Labs, Medicine Faculty, Catholic University of Maule, Talca, 3460000, Chile
| | - Ivan Schneider
- Biomedical Research Labs, Medicine Faculty, Catholic University of Maule, Talca, 3460000, Chile
| | - Cristian Lindner
- Biomedical Research Labs, Medicine Faculty, Catholic University of Maule, Talca, 3460000, Chile
| | - Armando Rojas
- Biomedical Research Labs, Medicine Faculty, Catholic University of Maule, Talca, 3460000, Chile
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57
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Buscaill P, van der Hoorn RAL. Defeated by the nines: nine extracellular strategies to avoid microbe-associated molecular patterns recognition in plants. THE PLANT CELL 2021; 33:2116-2130. [PMID: 33871653 PMCID: PMC8364246 DOI: 10.1093/plcell/koab109] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 04/07/2021] [Indexed: 05/13/2023]
Abstract
Recognition of microbe-associated molecular patterns (MAMPs) by cell-surface receptors is pivotal in host-microbe interactions. Both pathogens and symbionts establish plant-microbe interactions using fascinating intricate extracellular strategies to avoid recognition. Here we distinguish nine different extracellular strategies to avoid recognition by the host, acting at three different levels. To avoid the accumulation of MAMP precursors (Level 1), microbes take advantage of polymorphisms in both MAMP proteins and glycans, or downregulate MAMP production. To reduce hydrolytic MAMP release (Level 2), microbes shield MAMP precursors with proteins or glycans and inhibit or degrade host-derived hydrolases. And to prevent MAMP perception directly (Level 3), microbes degrade or sequester MAMPs before they are perceived. We discuss examples of these nine strategies and envisage three additional extracellular strategies to avoid MAMP perception in plants.
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Affiliation(s)
- Pierre Buscaill
- The Plant Chemetics Laboratory, Department of Plant Sciences, University of Oxford, OX1 3RB Oxford, UK
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58
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Bacterial Flagellar Filament: A Supramolecular Multifunctional Nanostructure. Int J Mol Sci 2021; 22:ijms22147521. [PMID: 34299141 PMCID: PMC8306008 DOI: 10.3390/ijms22147521] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/06/2021] [Accepted: 07/10/2021] [Indexed: 02/07/2023] Open
Abstract
The bacterial flagellum is a complex and dynamic nanomachine that propels bacteria through liquids. It consists of a basal body, a hook, and a long filament. The flagellar filament is composed of thousands of copies of the protein flagellin (FliC) arranged helically and ending with a filament cap composed of an oligomer of the protein FliD. The overall structure of the filament core is preserved across bacterial species, while the outer domains exhibit high variability, and in some cases are even completely absent. Flagellar assembly is a complex and energetically costly process triggered by environmental stimuli and, accordingly, highly regulated on transcriptional, translational and post-translational levels. Apart from its role in locomotion, the filament is critically important in several other aspects of bacterial survival, reproduction and pathogenicity, such as adhesion to surfaces, secretion of virulence factors and formation of biofilms. Additionally, due to its ability to provoke potent immune responses, flagellins have a role as adjuvants in vaccine development. In this review, we summarize the latest knowledge on the structure of flagellins, capping proteins and filaments, as well as their regulation and role during the colonization and infection of the host.
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59
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Faass L, Stein SC, Hauke M, Gapp M, Albanese M, Josenhans C. Contribution of Heptose Metabolites and the cag Pathogenicity Island to the Activation of Monocytes/Macrophages by Helicobacter pylori. Front Immunol 2021; 12:632154. [PMID: 34093525 PMCID: PMC8174060 DOI: 10.3389/fimmu.2021.632154] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 04/12/2021] [Indexed: 12/11/2022] Open
Abstract
The human gastric pathogen Helicobacter pylori activates human epithelial cells by a particular combination of mechanisms, including NOD1 and ALPK1-TIFA activation. These mechanisms are characterized by a strong participation of the bacterial cag pathogenicity island, which forms a type IV secretion system (CagT4SS) that enables the bacteria to transport proteins and diverse bacterial metabolites, including DNA, glycans, and cell wall components, into human host cells. Building on previous findings, we sought to determine the contribution of lipopolysaccharide inner core heptose metabolites (ADP-heptose) in the activation of human phagocytic cells by H. pylori. Using human monocyte/macrophage-like Thp-1 cells and human primary monocytes and macrophages, we were able to determine that a substantial part of early phagocytic cell activation, including NF-κB activation and IL-8 production, by live H. pylori is triggered by bacterial heptose metabolites. This effect was very pronounced in Thp-1 cells exposed to bacterial purified lysates or pure ADP-heptose, in the absence of other bacterial MAMPs, and was significantly reduced upon TIFA knock-down. Pure ADP-heptose on its own was able to strongly activate Thp-1 cells and human primary monocytes/macrophages. Comprehensive transcriptome analysis of Thp-1 cells co-incubated with live H. pylori or pure ADP-heptose confirmed a signature of ADP-heptose-dependent transcript activation in monocyte/macrophages. Bacterial enzyme-treated lysates (ETL) and pure ADP-heptose–dependent activation differentiated monocytes into macrophages of predominantly M1 type. In Thp-1 cells, the active CagT4SS was less required for the heptose-induced proinflammatory response than in epithelial cells, while active heptose biosynthesis or pure ADP-heptose was required and sufficient for their early innate response and NF-κB activation. The present data suggest that early activation and maturation of incoming and resident phagocytic cells (monocytes, macrophages) in the H. pylori–colonized stomach strongly depend on bacterial LPS inner core heptose metabolites, also with a significant contribution of an active CagT4SS.
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Affiliation(s)
- Larissa Faass
- Max von Pettenkofer Institute, Chair for Medical Microbiology and Hygiene, Ludwig Maximilians University Munich, Munich, Germany
| | - Saskia C Stein
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Martina Hauke
- Max von Pettenkofer Institute, Chair for Medical Microbiology and Hygiene, Ludwig Maximilians University Munich, Munich, Germany
| | - Madeleine Gapp
- Max von Pettenkofer Institute, Chair for Virology, Ludwig Maximilians University, Munich, Germany.,Gene Center and Department of Biochemistry, LMU Munich, Munich, Germany
| | - Manuel Albanese
- Max von Pettenkofer Institute, Chair for Virology, Ludwig Maximilians University, Munich, Germany.,Gene Center and Department of Biochemistry, LMU Munich, Munich, Germany
| | - Christine Josenhans
- Max von Pettenkofer Institute, Chair for Medical Microbiology and Hygiene, Ludwig Maximilians University Munich, Munich, Germany.,Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany.,German Center of Infection Research (DZIF), Partner site Munich, Munich, Germany.,DZIF, Partner site Hannover-Braunschweig, Hannover, Germany
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60
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Toll-like Receptor 5 Activation by the CagY Repeat Domains of Helicobacter pylori. Cell Rep 2021; 32:108159. [PMID: 32937132 DOI: 10.1016/j.celrep.2020.108159] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 07/01/2020] [Accepted: 08/24/2020] [Indexed: 02/07/2023] Open
Abstract
Helicobacter pylori (Hp) is an important human pathogen associated with gastric inflammation and neoplasia. It is commonly believed that this bacterium avoids major immune recognition by Toll-like receptors (TLRs) because of low intrinsic activity of its flagellin and lipopolysaccharides (LPS). In particular, TLR5 specifically detects flagellins in various bacterial pathogens, while Hp evolved mutations in flagellin to evade detection through TLR5. Cancerogenic Hp strains encode a type IV secretion system (T4SS). The T4SS core component and pilus-associated protein CagY, a large VirB10 ortholog, drives effector molecule translocation. Here, we identify CagY as a flagellin-independent TLR5 agonist. We detect five TLR5 interaction sites, promoting binding of CagY-positive Hp to TLR5-expressing cells, TLR5 stimulation, and intracellular signal transduction. Consequently, CagY constitutes a remarkable VirB10 member detected by TLR5, driving crucial innate immune responses by this human pathogen.
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Jiao H, Zhou Z, Li B, Xiao Y, Li M, Zeng H, Guo X, Gu G. The Mechanism of Facultative Intracellular Parasitism of Brucella. Int J Mol Sci 2021; 22:ijms22073673. [PMID: 33916050 PMCID: PMC8036852 DOI: 10.3390/ijms22073673] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/22/2021] [Accepted: 03/30/2021] [Indexed: 01/18/2023] Open
Abstract
Brucellosis is a highly prevalent zoonotic disease characterized by abortion and reproductive dysfunction in pregnant animals. Although the mortality rate of Brucellosis is low, it is harmful to human health, and also seriously affects the development of animal husbandry, tourism and international trade. Brucellosis is caused by Brucella, which is a facultative intracellular parasitic bacteria. It mainly forms Brucella-containing vacuoles (BCV) in the host cell to avoid the combination with lysosome (Lys), so as to avoid the elimination of it by the host immune system. Brucella not only has the ability to resist the phagocytic bactericidal effect, but also can make the host cells form a microenvironment which is conducive to its survival, reproduction and replication, and survive in the host cells for a long time, which eventually leads to the formation of chronic persistent infection. Brucella can proliferate and replicate in cells, evade host immune response and induce persistent infection, which are difficult problems in the treatment and prevention of Brucellosis. Therefore, the paper provides a preliminary overview of the facultative intracellular parasitic and immune escape mechanisms of Brucella, which provides a theoretical basis for the later study on the pathogenesis of Brucella.
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Affiliation(s)
- Hanwei Jiao
- Immunology Research Center, Medical Research Institute, Southwest University, Chongqing 402460, China
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (Z.Z.); (B.L.); (Y.X.); (M.L.); (H.Z.); (X.G.); (G.G.)
- Veterinary Scientific Engineering Research Center, Chongqing 402460, China
- Correspondence:
| | - Zhixiong Zhou
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (Z.Z.); (B.L.); (Y.X.); (M.L.); (H.Z.); (X.G.); (G.G.)
| | - Bowen Li
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (Z.Z.); (B.L.); (Y.X.); (M.L.); (H.Z.); (X.G.); (G.G.)
| | - Yu Xiao
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (Z.Z.); (B.L.); (Y.X.); (M.L.); (H.Z.); (X.G.); (G.G.)
| | - Mengjuan Li
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (Z.Z.); (B.L.); (Y.X.); (M.L.); (H.Z.); (X.G.); (G.G.)
| | - Hui Zeng
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (Z.Z.); (B.L.); (Y.X.); (M.L.); (H.Z.); (X.G.); (G.G.)
| | - Xiaoyi Guo
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (Z.Z.); (B.L.); (Y.X.); (M.L.); (H.Z.); (X.G.); (G.G.)
| | - Guojing Gu
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (Z.Z.); (B.L.); (Y.X.); (M.L.); (H.Z.); (X.G.); (G.G.)
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62
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Gauthier AE, Chandler CE, Poli V, Gardner FM, Tekiau A, Smith R, Bonham KS, Cordes EE, Shank TM, Zanoni I, Goodlett DR, Biller SJ, Ernst RK, Rotjan RD, Kagan JC. Deep-sea microbes as tools to refine the rules of innate immune pattern recognition. Sci Immunol 2021; 6:eabe0531. [PMID: 33712473 PMCID: PMC8367048 DOI: 10.1126/sciimmunol.abe0531] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 02/11/2021] [Indexed: 01/04/2023]
Abstract
The assumption of near-universal bacterial detection by pattern recognition receptors is a foundation of immunology. The limits of this pattern recognition concept, however, remain undefined. As a test of this hypothesis, we determined whether mammalian cells can recognize bacteria that they have never had the natural opportunity to encounter. These bacteria were cultivated from the deep Pacific Ocean, where the genus Moritella was identified as a common constituent of the culturable microbiota. Most deep-sea bacteria contained cell wall lipopolysaccharide (LPS) structures that were expected to be immunostimulatory, and some deep-sea bacteria activated inflammatory responses from mammalian LPS receptors. However, LPS receptors were unable to detect 80% of deep-sea bacteria examined, with LPS acyl chain length being identified as a potential determinant of immunosilence. The inability of immune receptors to detect most bacteria from a different ecosystem suggests that pattern recognition strategies may be defined locally, not globally.
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Affiliation(s)
- Anna E Gauthier
- Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
- Program in Virology, Harvard Medical School, Boston, MA 02115, USA
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
| | - Courtney E Chandler
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, 650 W. Baltimore Street, Baltimore, MD 21201, USA
| | - Valentina Poli
- Harvard Medical School, and Boston Children's Hospital, Division of Immunology, Division of Gastroenterology, Boston, MA 02115, USA
| | - Francesca M Gardner
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, 650 W. Baltimore Street, Baltimore, MD 21201, USA
| | | | - Richard Smith
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, 650 W. Baltimore Street, Baltimore, MD 21201, USA
| | - Kevin S Bonham
- Department of Biological Sciences, Wellesley College, 106 Central St., Wellesley, MA 02481, USA
| | - Erik E Cordes
- Department of Biology, Temple University, 1900 N. 12th St., Philadelphia, PA 19122, USA
| | - Timothy M Shank
- Biology Department, MS33, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Ivan Zanoni
- Harvard Medical School, and Boston Children's Hospital, Division of Immunology, Division of Gastroenterology, Boston, MA 02115, USA
| | - David R Goodlett
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, 650 W. Baltimore Street, Baltimore, MD 21201, USA
- International Centre for Cancer Vaccine Science, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland
| | - Steven J Biller
- Department of Biological Sciences, Wellesley College, 106 Central St., Wellesley, MA 02481, USA
| | - Robert K Ernst
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, 650 W. Baltimore Street, Baltimore, MD 21201, USA
| | - Randi D Rotjan
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA.
| | - Jonathan C Kagan
- Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA.
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Abstract
Campylobacter jejuni and Campylobacter coli can be frequently isolated from poultry and poultry-derived products, and in combination these two species cause a large portion of human bacterial gastroenteritis cases. While birds are typically colonized by these Campylobacter species without clinical symptoms, in humans they cause (foodborne) infections at high frequencies, estimated to cost billions of dollars worldwide every year. The clinical outcome of Campylobacter infections comprises malaise, diarrhea, abdominal pain and fever. Symptoms may continue for up to two weeks and are generally self-limiting, though occasionally the disease can be more severe or result in post-infection sequelae. The virulence properties of these pathogens have been best-characterized for C. jejuni, and their actions are reviewed here. Various virulence-associated bacterial determinants include the flagellum, numerous flagellar secreted factors, protein adhesins, cytolethal distending toxin (CDT), lipooligosaccharide (LOS), serine protease HtrA and others. These factors are involved in several pathogenicity-linked properties that can be divided into bacterial chemotaxis, motility, attachment, invasion, survival, cellular transmigration and spread to deeper tissue. All of these steps require intimate interactions between bacteria and host cells (including immune cells), enabled by the collection of bacterial and host factors that have already been identified. The assortment of pathogenicity-associated factors now recognized for C. jejuni, their function and the proposed host cell factors that are involved in crucial steps leading to disease are discussed in detail.
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Traulsen J, Zagami C, Daddi AA, Boccellato F. Molecular modelling of the gastric barrier response, from infection to carcinogenesis. Best Pract Res Clin Gastroenterol 2021; 50-51:101737. [PMID: 33975688 DOI: 10.1016/j.bpg.2021.101737] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 02/07/2023]
Abstract
The lining of the stomach is a tight monolayer of epithelial cells performing functions in digestion and a protective barrier against gastric acid, toxic metabolites and infectious agents, including Helicobacter pylori. The response of the epithelial barrier to infections underlies gastric pathologies, including gastric cancer. H. pylori has the unique capacity to colonise the gastric mucosa while evading the immune system. The colonised mucosa initiates an inflammatory response to fight the infection and a strong regenerative program to avoid barrier failure and ulceration. This response changes the morphology and cell composition of the gastric epithelium and in parallel it might contribute to the accumulation of somatic mutations leading to cellular transformation. Genetically modified mice, cell lines and human-derived organoids are the main biological models to study the gastric epithelial barrier. With these models it is possible to dissect the stepwise process of tissue adaptation to infection that places the epithelium at risk of malignant transformation.
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Affiliation(s)
- Jan Traulsen
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, United Kingdom.
| | - Claudia Zagami
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, United Kingdom.
| | - Alice Anna Daddi
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, United Kingdom.
| | - Francesco Boccellato
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, United Kingdom.
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65
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Genetic Variation in Toll-Like Receptor 5 and Colonization with Flagellated Bacterial Vaginosis-Associated Bacteria. Infect Immun 2021; 89:IAI.00060-20. [PMID: 33199356 PMCID: PMC8097276 DOI: 10.1128/iai.00060-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 11/12/2020] [Indexed: 02/06/2023] Open
Abstract
Bacterial vaginosis (BV) is a vaginal dysbiotic condition linked to negative gynecological and reproductive sequelae. Flagellated bacteria have been identified in women with BV, including Mobiluncus spp. and BV-associated bacterium-1 (BVAB1), an uncultivated, putatively flagellated species. The host response to flagellin mediated through Toll-like receptor 5 (TLR5) has not been explored in BV. Using independent discovery and validation cohorts, we examined the hypothesis that TLR5 deficiency-defined by a dominant negative stop codon polymorphism, rs5744168-is associated with an increased risk for BV and increased colonization with flagellated bacteria associated with BV (BVAB1, Mobiluncus curtisii, and Mobiluncus mulieris). TLR5 deficiency was not associated with BV status, and TLR5-deficient women had decreased colonization with BVAB1 in both cohorts. We stimulated HEK-hTLR5-overexpressing NF-κB reporter cells with whole, heat-killed M. mulieris or M. curtisii and with partially purified flagellin from these species; as BVAB1 is uncultivated, we used cervicovaginal lavage (CVL) fluid supernatant from women colonized with BVAB1 for stimulation. While heat-killed M. mulieris and CVL fluid from women colonized with BVAB1 stimulate a TLR5-mediated response, heat-killed M. curtisii did not. In contrast, partially purified flagellin from both Mobiluncus species stimulated a TLR5-mediated response in vitro We observed no correlation between vaginal interleukin 8 (IL-8) and flagellated BVAB concentrations among TLR5-sufficient women. Interspecies variation in accessibility of flagellin recognition domains may be responsible for these observations, as reflected in the potentially novel flagellin products encoded by Mobiluncus species versus those encoded by BVAB1.
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66
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Gao Q, Yi S, Luo J, Xing Q, Lv J, Wang P, Wang C, Li Y. Construction of a Vibrio anguillarum flagellin B mutant and analysis of its immuno-stimulation effects on Macrobrachium rosenbergii. Int J Biol Macromol 2021; 174:457-465. [PMID: 33493561 DOI: 10.1016/j.ijbiomac.2021.01.146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/20/2021] [Accepted: 01/20/2021] [Indexed: 01/16/2023]
Abstract
Vibrio anguillarum is a globally distributed aquatic pathogen, and its flagellin B (FlaB) protein can evoke innate immune responses in hosts. In order to explore the role of FlaB in V. anguillarum infection, we constructed a FlaB-deficient mutant using overlapping PCR and two-step homologous recombination, and gene sequencing confirmed successful knockout of the FlaB gene. Scanning electron microscopy showed no significant differences in the morphological structure of the flagellum between wild-type and FlaB-deficient strains. The mutant was subsequently injected into the freshwater prawn (Macrobrachium rosenbergii) to explore its pathogenicity in the host, and expression of myeloid differentiation factor 88, prophenoloxidase, catalase, superoxide dismutase and glutathione peroxidase was investigated by real-time PCR. The results showed that deletion of FlaB had little effect on V. anguillarum-induced expression of these immune-related genes (p > 0.05). In general, the FlaB mutant displayed similar flagella morphology and immune characteristics to the wild-type strain, hence we speculated that knockout of FlaB might promote the expression and function of other flagellin proteins. Furthermore, this study provides a rapid and simple method for obtaining stable mutants of V. anguillarum free from foreign plasmid DNA.
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Affiliation(s)
- Quanxin Gao
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Shaokui Yi
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Jinping Luo
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Qianqian Xing
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Jiali Lv
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Panhuang Wang
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Cuihua Wang
- Key Laboratory of Marine and Estuarine Fisheries, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, People's Republic of China.
| | - Yang Li
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China.
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67
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Chen H, Raffaele S, Dong S. Silent control: microbial plant pathogens evade host immunity without coding sequence changes. FEMS Microbiol Rev 2021; 45:6095737. [PMID: 33440001 DOI: 10.1093/femsre/fuab002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 01/11/2021] [Indexed: 12/16/2022] Open
Abstract
Both animals and plants have evolved a robust immune system to surveil and defeat invading pathogenic microbes. Evasion of host immune surveillance is the key for pathogens to initiate successful infection. To evade the host immunity, plant pathogens evolved a variety of strategies such as masking themselves from host immune recognitions, blocking immune signaling transductions, reprogramming immune responses and adapting to immune microenvironmental changes. Gain of new virulence genes, sequence and structural variations enables plant pathogens to evade host immunity through changes in the genetic code. However, recent discoveries demonstrated that variations at the transcriptional, post-transcriptional, post-translational and glycome level enable pathogens to cope with the host immune system without coding sequence changes. The biochemical modification of pathogen associated molecular patterns and silencing of effector genes emerged as potent ways for pathogens to hide from host recognition. Altered processing in mRNA activities provide pathogens with resilience to microenvironment changes. Importantly, these hiding variants are directly or indirectly modulated by catalytic enzymes or enzymatic complexes and cannot be revealed by classical genomics alone. Unveiling these novel host evasion mechanisms in plant pathogens enables us to better understand the nature of plant disease and pinpoints strategies for rational diseases management in global food protection.
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Affiliation(s)
- Han Chen
- Department of Plant Pathology and The Key Laboratory of Plant Immunity, Nanjing Agricultural University, 210095, Nanjing, China
| | - Sylvain Raffaele
- Laboratoire des Interactions Plantes-Microorganismes, INRAE, CNRS, 24 Chemin de Borde Rouge - Auzeville, CS52627, F31326 Castanet Tolosan Cedex, France
| | - Suomeng Dong
- Department of Plant Pathology and The Key Laboratory of Plant Immunity, Nanjing Agricultural University, 210095, Nanjing, China
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68
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Kreling V, Falcone FH, Kehrenberg C, Hensel A. Campylobacter sp.: Pathogenicity factors and prevention methods-new molecular targets for innovative antivirulence drugs? Appl Microbiol Biotechnol 2020; 104:10409-10436. [PMID: 33185702 PMCID: PMC7662028 DOI: 10.1007/s00253-020-10974-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 08/24/2020] [Accepted: 10/21/2020] [Indexed: 02/08/2023]
Abstract
Infections caused by bacterial species from the genus Campylobacter are one of the four main causes of strong diarrheal enteritis worldwide. Campylobacteriosis, a typical food-borne disease, can range from mild symptoms to fatal illness. About 550 million people worldwide suffer from campylobacteriosis and lethality is about 33 million p.a. This review summarizes the state of the current knowledge on Campylobacter with focus on its specific virulence factors. Using this knowledge, multifactorial prevention strategies can be implemented to reduce the prevalence of Campylobacter in the food chain. In particular, antiadhesive strategies with specific adhesion inhibitors seem to be a promising concept for reducing Campylobacter bacterial load in poultry production. Antivirulence compounds against bacterial adhesion to and/or invasion into the host cells can open new fields for innovative antibacterial agents. Influencing chemotaxis, biofilm formation, quorum sensing, secretion systems, or toxins by specific inhibitors can help to reduce virulence of the bacterium. In addition, the unusual glycosylation of the bacterium, being a prerequisite for effective phase variation and adaption to different hosts, is yet an unexplored target for combating Campylobacter sp. Plant extracts are widely used remedies in developing countries to combat infections with Campylobacter. Therefore, the present review summarizes the use of natural products against the bacterium in an attempt to stimulate innovative research concepts on the manifold still open questions behind Campylobacter towards improved treatment and sanitation of animal vectors, treatment of infected patients, and new strategies for prevention. KEY POINTS: • Campylobacter sp. is a main cause of strong enteritis worldwide. • Main virulence factors: cytolethal distending toxin, adhesion proteins, invasion machinery. • Strong need for development of antivirulence compounds.
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Affiliation(s)
- Vanessa Kreling
- Institute of Pharmaceutical Biology and Phytochemistry, University of Münster, Corrensstraße 48, 48149, Münster, Germany
| | - Franco H Falcone
- Institute of Parasitology, University of Gießen, Schubertstraße 81, 35392, Gießen, Germany
| | - Corinna Kehrenberg
- Institute of Veterinary Food Science, University of Gießen, Frankfurterstraße 81, 35392, Gießen, Germany
| | - Andreas Hensel
- Institute of Pharmaceutical Biology and Phytochemistry, University of Münster, Corrensstraße 48, 48149, Münster, Germany.
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69
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Yambe N, Tamai R, Mashima I, Kiyoura Y. Etidronate down-regulates Toll-like receptor 2 ligand-induced chemokine production by inhibiting MyD88 expression and NF-κB activation. Immunopharmacol Immunotoxicol 2020; 43:51-57. [PMID: 33251898 DOI: 10.1080/08923973.2020.1850761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECTIVE Pretreatment of J774.1 cells with etidronate, a non-nitrogen-containing bisphosphonate (non-NBP) used as an antibone resorptive drug, was previously reported to inhibit Toll-like receptor (TLR) 2 agonist-induced proinflammatory cytokine production. The present study aimed to examine the effects of etidronate on chemokine production by human monocytic U937 cells incubated with Pam3Cys-Ser-(Lys)4 (Pam3CSK4, a TLR2 ligand) and lipid A (a TLR4 ligand). METHODS U937 cells were pretreated with or without etidronate, and then incubated with or without Pam3CSK4 or lipid A. Levels of secreted human interleukin (IL)-8 and monocyte chemoattractant protein-1 (MCP-1) in culture supernatants and activation of nuclear factor-κB (NF-κB) p65 were measured by enzyme-linked immunosorbent assay (ELISA). Cytotoxicity was determined by measuring lactate dehydrogenase (LDH) activity in supernatants. Expression of intracellular adhesion molecule (ICAM)-1 and MyD88 was analyzed by flow cytometry and Western blot analysis, respectively. RESULTS Etidronate down-regulated IL-8 and MCP-1 production and NF-κB p65 activation induced by Pam3CSK4, but not lipid A, in U937 cells. Etidronate also inhibited MyD88 expression in U937 cells incubated with Pam3CSK4. CONCLUSION Etidronate down-regulates IL-8 and MCP-1 production in U937 cells by inhibiting both the expression of MyD88 and activation of NF-κB p65 in the TLR2, but not TLR4, pathway.
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Affiliation(s)
- Naohito Yambe
- Department of Infectious Diseases, Ohu University Graduate School of Dentistry, Koriyama, Japan
| | - Riyoko Tamai
- Department of Infectious Diseases, Ohu University Graduate School of Dentistry, Koriyama, Japan.,Department of Oral Medical Science, Ohu University School of Dentistry, Koriyama, Japan
| | - Izumi Mashima
- Department of Oral Medical Science, Ohu University School of Dentistry, Koriyama, Japan
| | - Yusuke Kiyoura
- Department of Infectious Diseases, Ohu University Graduate School of Dentistry, Koriyama, Japan.,Department of Oral Medical Science, Ohu University School of Dentistry, Koriyama, Japan
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70
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Toll-Like Receptor-4 Is Involved in Mediating Intestinal and Extra-Intestinal Inflammation in Campylobacter coli-Infected Secondary Abiotic IL-10 -/- Mice. Microorganisms 2020; 8:microorganisms8121882. [PMID: 33261211 PMCID: PMC7761268 DOI: 10.3390/microorganisms8121882] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/24/2020] [Accepted: 11/25/2020] [Indexed: 01/01/2023] Open
Abstract
Human Campylobacter infections are emerging worldwide and constitute significant health burdens. We recently showed that the immunopathological sequelae in Campylobacter jejuni-infected mice were due to Toll-like receptor (TLR)-4 dependent immune responses induced by bacterial lipooligosaccharide (LOS). Information regarding the molecular mechanisms underlying Campylobacter coli-host interactions are scarce, however. Therefore, we analyzed C. coli-induced campylobacteriosis in secondary abiotic IL-10−/− mice with and without TLR4. Mice were infected perorally with a human C. coli isolate or with a murine commensal Escherichia coli as apathogenic, non-invasive control. Independent from TLR4, C. coli and E. coli stably colonized the gastrointestinal tract, but only C. coli induced clinical signs of campylobacteriosis. TLR4−/− IL-10−/− mice, however, displayed less frequently fecal blood and less distinct histopathological and apoptotic sequelae in the colon versus IL-10−/− counterparts on day 28 following C. coli infection. Furthermore, C. coli-induced colonic immune cell responses were less pronounced in TLR4−/− IL-10−/− as compared to IL-10−/− mice and accompanied by lower pro-inflammatory mediator concentrations in the intestines and the liver of the former versus the latter. In conclusion, our study provides evidence that TLR4 is involved in mediating C. coli-LOS-induced immune responses in intestinal and extra-intestinal compartments during murine campylobacteriosis.
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71
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Eckhard U, Blöchl C, Jenkins BGL, Mansfield MJ, Huber CG, Doxey AC, Brandstetter H. Identification and characterization of the proteolytic flagellin from the common freshwater bacterium Hylemonella gracilis. Sci Rep 2020; 10:19052. [PMID: 33149258 PMCID: PMC7643111 DOI: 10.1038/s41598-020-76010-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 10/22/2020] [Indexed: 12/14/2022] Open
Abstract
Flagellins are the protein components of bacterial flagella and assemble in up to 20,000 copies to form extracellular flagellar filaments. An unusual family of flagellins was recently discovered that contains a unique metalloprotease domain within its surface-exposed hypervariable region. To date, these proteolytic flagellins (also termed flagellinolysins) have only been characterized in the Gram-positive organism Clostridium haemolyticum, where flagellinolysin was shown to be proteolytically active and capable of cleaving extracellular protein substrates. The biological function of flagellinolysin and its activity in other organisms, however, remain unclear. Here, using molecular biochemistry and proteomics, we have performed an initial characterization of a novel flagellinolysin identified from Hylemonella gracilis, a Gram-negative organism originally isolated from pond water. We demonstrate that H. gracilis flagellinolysin (HgrFlaMP) is an active calcium-dependent zinc metallopeptidase and characterize its cleavage specificity profile using both trypsin and GluC-derived peptide libraries and protein substrates. Based on high-throughput degradomic assays, HgrFlaMP cleaved 784 unique peptides and displayed a cleavage site specificity similar to flagellinolysin from C. haemolyticum. Additionally, by using a set of six protein substrates, we identified 206 protein-embedded cleavage sites, further refining the substrate preference of HgrFlaMP, which is dominated by large hydrophobic amino acids in P1', and small hydrophobic or medium-sized polar residues on the amino-terminal side of the scissile bond. Intriguingly, recombinant HgrFlaMP was also capable of cleaving full-length flagellins from another species, suggesting its potential involvement in interbacterial interactions. Our study reports the first experimentally characterized proteolytic flagellin in a Gram-negative organism, and provides new insights into flagellum-mediated enzymatic activity.
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Affiliation(s)
- Ulrich Eckhard
- Department of Biosciences, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria. .,Proteolysis Lab, Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, Baldiri Reixac, 15-21, 08028, Barcelona, Catalonia, Spain.
| | - Constantin Blöchl
- Department of Biosciences, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria
| | - Benjamin G L Jenkins
- Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, ON, N2L 3G1, Canada
| | - Michael J Mansfield
- Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, ON, N2L 3G1, Canada.,Genomics and Regulatory Sytems Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan
| | - Christian G Huber
- Department of Biosciences, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria.,Christian Doppler Laboratory for Innovative Tools for Biosimilar Characterization, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria
| | - Andrew C Doxey
- Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, ON, N2L 3G1, Canada.
| | - Hans Brandstetter
- Department of Biosciences, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria.,Christian Doppler Laboratory for Innovative Tools for Biosimilar Characterization, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria
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Sarajlic M, Neuper T, Vetter J, Schaller S, Klicznik MM, Gratz IK, Wessler S, Posselt G, Horejs-Hoeck J. H. pylori modulates DC functions via T4SS/TNFα/p38-dependent SOCS3 expression. Cell Commun Signal 2020; 18:160. [PMID: 33023610 PMCID: PMC7541176 DOI: 10.1186/s12964-020-00655-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 09/06/2020] [Indexed: 12/11/2022] Open
Abstract
Background Helicobacter pylori (H. pylori) is a gram-negative bacterium that chronically infects approximately 50% of the world’s human population. While in most cases the infection remains asymptomatic, 10% of infected individuals develop gastric pathologies and 1–3% progress to gastric cancer. Although H. pylori induces severe inflammatory responses, the host’s immune system fails to clear the pathogen and H. pylori can persist in the human stomach for decades. As suppressor of cytokine signaling (SOCS) proteins are important feedback regulators limiting inflammatory responses, we hypothesized that H. pylori could modulate the host’s immune responses by inducing SOCS expression. Methods The phenotype of human monocyte-derived DCs (moDCs) infected with H. pylori was analyzed by flow cytometry and multiplex technology. SOCS expression levels were monitored by qPCR and signaling studies were conducted by means of Western blot. For functional studies, RNA interference-based silencing of SOCS1–3 and co-cultures with CD4+ T cells were performed. Results We show that H. pylori positive gastritis patients express significantly higher SOCS3, but not SOCS1 and SOCS2, levels compared to H. pylori negative patients. Moreover, infection of human moDCs with H. pylori rapidly induces SOCS3 expression, which requires the type IV secretion system (T4SS), release of TNFα, and signaling via the MAP kinase p38, but appears to be independent of TLR2, TLR4, MEK1/2 and STAT proteins. Silencing of SOCS3 expression in moDCs prior to H. pylori infection resulted in increased release of both pro- and anti-inflammatory cytokines, upregulation of PD-L1, and decreased T-cell proliferation. Conclusions This study shows that H. pylori induces SOCS3 via an autocrine loop involving the T4SS and TNFα and p38 signaling. Moreover, we demonstrate that high levels of SOCS3 in DCs dampen PD-L1 expression on DCs, which in turn drives T-cell proliferation. Video Abstract
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Affiliation(s)
- Muamera Sarajlic
- Department of Biosciences, University of Salzburg, Hellbrunner Strasse 34, 5020, Salzburg, Austria
| | - Theresa Neuper
- Department of Biosciences, University of Salzburg, Hellbrunner Strasse 34, 5020, Salzburg, Austria
| | - Julia Vetter
- Bioinformatics Research Group, University of Applied Sciences Upper Austria, Hagenberg im Muehlkreis, Austria
| | - Susanne Schaller
- Bioinformatics Research Group, University of Applied Sciences Upper Austria, Hagenberg im Muehlkreis, Austria
| | - Maria M Klicznik
- Department of Biosciences, University of Salzburg, Hellbrunner Strasse 34, 5020, Salzburg, Austria
| | - Iris K Gratz
- Department of Biosciences, University of Salzburg, Hellbrunner Strasse 34, 5020, Salzburg, Austria
| | - Silja Wessler
- Department of Biosciences, University of Salzburg, Hellbrunner Strasse 34, 5020, Salzburg, Austria
| | - Gernot Posselt
- Department of Biosciences, University of Salzburg, Hellbrunner Strasse 34, 5020, Salzburg, Austria
| | - Jutta Horejs-Hoeck
- Department of Biosciences, University of Salzburg, Hellbrunner Strasse 34, 5020, Salzburg, Austria.
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73
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Kreutzberger MAB, Ewing C, Poly F, Wang F, Egelman EH. Atomic structure of the Campylobacter jejuni flagellar filament reveals how ε Proteobacteria escaped Toll-like receptor 5 surveillance. Proc Natl Acad Sci U S A 2020; 117:16985-16991. [PMID: 32641510 PMCID: PMC7382276 DOI: 10.1073/pnas.2010996117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vertebrates, from zebra fish to humans, have an innate immune recognition of many bacterial flagellins. This involves a conserved eight-amino acid epitope in flagellin recognized by the Toll-like receptor 5 (TLR5). Several important human pathogens, such as Helicobacter pylori and Campylobacter jejuni, have escaped TLR5 activation by mutations in this epitope. When such mutations were introduced into Salmonella flagellin, motility was abolished. It was previously argued, using very low-resolution cryoelectron microscopy (cryo-EM), that C. jejuni accommodated these mutations by forming filaments with 7 protofilaments, rather than the 11 found in other bacteria. We have now determined the atomic structure of the C. jejuni G508A flagellar filament from a 3.5-Å-resolution cryo-EM reconstruction, and show that it has 11 protofilaments. The residues in the C. jejuni TLR5 epitope have reduced contacts with the adjacent subunit compared to other bacterial flagellar filament structures. The weakening of the subunit-subunit interface introduced by the mutations in the TLR5 epitope is compensated for by extensive interactions between the outer domains of the flagellin subunits. In other bacteria, these outer domains can be nearly absent or removed without affecting motility. Furthermore, we provide evidence for the stabilization of these outer domain interactions through glycosylation of key residues. These results explain the essential role of glycosylation in C. jejuni motility, and show how the outer domains have evolved to play a role not previously found in other bacteria.
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Affiliation(s)
- Mark A B Kreutzberger
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903
| | - Cheryl Ewing
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910
| | - Frederic Poly
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910
| | - Fengbin Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903;
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74
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Li B, Xia Y, Hu B. Infection and atherosclerosis: TLR-dependent pathways. Cell Mol Life Sci 2020; 77:2751-2769. [PMID: 32002588 PMCID: PMC7223178 DOI: 10.1007/s00018-020-03453-7] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 01/02/2020] [Accepted: 01/03/2020] [Indexed: 12/15/2022]
Abstract
Atherosclerotic vascular disease (ASVD) is a chronic process, with a progressive course over many years, but it can cause acute clinical events, including acute coronary syndromes (ACS), myocardial infarction (MI) and stroke. In addition to a series of typical risk factors for atherosclerosis, like hyperlipidemia, hypertension, smoking and obesity, emerging evidence suggests that atherosclerosis is a chronic inflammatory disease, suggesting that chronic infection plays an important role in the development of atherosclerosis. Toll-like receptors (TLRs) are the most characteristic members of pattern recognition receptors (PRRs), which play an important role in innate immune mechanism. TLRs play different roles in different stages of infection of atherosclerosis-related pathogens such as Chlamydia pneumoniae (C. pneumoniae), periodontal pathogens including Porphyromonas gingivalis (P. gingivalis), Helicobacter pylori (H. pylori) and human immunodeficiency virus (HIV). Overall, activation of TLR2 and 4 seems to have a profound impact on infection-related atherosclerosis. This article reviews the role of TLRs in the process of atherosclerosis after C. pneumoniae and other infections and the current status of treatment, with a view to providing a new direction and potential therapeutic targets for the study of ASVD.
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Affiliation(s)
- Bowei Li
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yuanpeng Xia
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | - Bo Hu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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75
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Levy H, Fiddaman SR, Vianna JA, Noll D, Clucas GV, Sidhu JKH, Polito MJ, Bost CA, Phillips RA, Crofts S, Miller GD, Pistorius P, Bonnadonna F, Le Bohec C, Barbosa A, Trathan P, Raya Rey A, Frantz LAF, Hart T, Smith AL. Evidence of Pathogen-Induced Immunogenetic Selection across the Large Geographic Range of a Wild Seabird. Mol Biol Evol 2020; 37:1708-1726. [PMID: 32096861 PMCID: PMC7253215 DOI: 10.1093/molbev/msaa040] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Over evolutionary time, pathogen challenge shapes the immune phenotype of the host to better respond to an incipient threat. The extent and direction of this selection pressure depend on the local pathogen composition, which is in turn determined by biotic and abiotic features of the environment. However, little is known about adaptation to local pathogen threats in wild animals. The Gentoo penguin (Pygoscelis papua) is a species complex that lends itself to the study of immune adaptation because of its circumpolar distribution over a large latitudinal range, with little or no admixture between different clades. In this study, we examine the diversity in a key family of innate immune genes-the Toll-like receptors (TLRs)-across the range of the Gentoo penguin. The three TLRs that we investigated present varying levels of diversity, with TLR4 and TLR5 greatly exceeding the diversity of TLR7. We present evidence of positive selection in TLR4 and TLR5, which points to pathogen-driven adaptation to the local pathogen milieu. Finally, we demonstrate that two positively selected cosegregating sites in TLR5 are sufficient to alter the responsiveness of the receptor to its bacterial ligand, flagellin. Taken together, these results suggest that Gentoo penguins have experienced distinct pathogen-driven selection pressures in different environments, which may be important given the role of the Gentoo penguin as a sentinel species in some of the world's most rapidly changing environments.
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Affiliation(s)
- Hila Levy
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | | | - Juliana A Vianna
- Departamento de Ecosistemas y Medio Ambiente, Pontificia Universidad Católica de Chile, Macul, Santiago, Chile
| | - Daly Noll
- Departamento de Ecosistemas y Medio Ambiente, Pontificia Universidad Católica de Chile, Macul, Santiago, Chile
- Departamento de Ciencias Ecológicas, Instituto de Ecología y Biodiversidad, Universidad de Chile, Santiago, Chile
| | - Gemma V Clucas
- Cornell Atkinson Center for a Sustainable Future, Cornell University, Ithaca, NY
- Cornell Lab of Ornithology, Cornell University, Ithaca, NY
| | | | - Michael J Polito
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA
| | - Charles A Bost
- Centre d’Etudes Biologiques de Chizé (CEBC), UMR 7372 du CNRS‐Université de La Rochelle, Villiers‐en‐Bois, France
| | | | - Sarah Crofts
- Falklands Conservation, Stanley, Falkland Islands, United Kingdom
| | - Gary D Miller
- Microbiology and Immunology, PALM, University of Western Australia, Crawley, Western Australia, Australia
| | - Pierre Pistorius
- DST/NRF Centre of Excellence at the Percy FitzPatrick Institute for African Ornithology, Department of Zoology, Nelson Mandela University, Port Elizabeth, South Africa
| | - Francesco Bonnadonna
- CEFE UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE, Montpellier, France
| | - Céline Le Bohec
- Université de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg, France
- Département de Biologie Polaire, Centre Scientifique de Monaco, Monaco, Principality of Monaco
| | - Andrés Barbosa
- Museo Nacional de Ciencias Naturales, Departamento de Ecología Evolutiva, CSIC, Madrid, Spain
| | - Phil Trathan
- British Antarctic Survey, Cambridge, United Kingdom
| | - Andrea Raya Rey
- Centro Austral de Investigaciones Científicas – Consejo Nacional de Investigaciones Científicas y Técnicas (CADIC-CONICET), Ushuaia, Tierra del Fuego, Argentina
- Instituto de Ciencias Polares, Ambiente y Recursos Naturales, Universidad Nacional de Tierra del Fuego, Ushuaia, Tierra del Fuego, Argentina
- Wildlife Conservation Society, Buenos Aires, Argentina
| | - Laurent A F Frantz
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Tom Hart
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Adrian L Smith
- Department of Zoology, University of Oxford, Oxford, United Kingdom
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76
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Lam WWL, Sun K, Zhang H, Au SWN. Crystal Structure of Flagellar Export Chaperone FliS in Complex With Flagellin and HP1076 of Helicobacter pylori. Front Microbiol 2020; 11:787. [PMID: 32508757 PMCID: PMC7248283 DOI: 10.3389/fmicb.2020.00787] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 04/02/2020] [Indexed: 12/13/2022] Open
Abstract
Functional flagella formation is a widespread virulence factor that plays a critical role in survival and host colonization. Flagellar synthesis is a complex and highly coordinated process. The assembly of the axial structure beyond the cell membrane is mediated by export chaperone proteins that transport their cognate substrates to the export gate complex. The export chaperone FliS interacts with flagellin, the basic component used to construct the filament. Unlike enterobacteria, the gastric pathogen Helicobacter pylori produces two different flagellins, FlaA and FlaB, which exhibit distinct spatial localization patterns in the filament. Previously, we demonstrated a molecular interaction between FliS and an uncharacterized protein, HP1076, in H. pylori. Here, we present the crystal structure of FliS in complex with both the C-terminal D0 domain of FlaB and HP1076. Although this ternary complex reveals that FliS interacts with flagellin using a conserved binding mode demonstrated previously in Aquifex aeolicus, Bacillus subtilis, and Salmonella enterica serovar Typhimurium, the helical conformation of FlaB in this complex was different. Moreover, HP1076 and the D1 domain of flagellin share structural similarity and interact with the same binding interface on FliS. This observation was further validated through competitive pull-down assays and kinetic binding analyses. Interestingly, we did not observe any detrimental flagellation or motility phenotypes in an hp1076-null strain. Our localization studies suggest that HP1076 is a membrane-associated protein with a cellular localization independent of FliS. As HP1076 is uniquely expressed in H. pylori and related species, we propose that this protein may contribute to the divergence of the flagellar system, although its relationship with FliS remains incompletely elucidated.
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Affiliation(s)
- Wendy Wai-Ling Lam
- Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Kailei Sun
- Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Huawei Zhang
- Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Shannon Wing-Ngor Au
- Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong
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77
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Yan Y, Drew DA, Markowitz A, Lloyd-Price J, Abu-Ali G, Nguyen LH, Tran C, Chung DC, Gilpin KK, Meixell D, Parziale M, Schuck M, Patel Z, Richter JM, Kelsey PB, Garrett WS, Chan AT, Stadler ZK, Huttenhower C. Structure of the Mucosal and Stool Microbiome in Lynch Syndrome. Cell Host Microbe 2020; 27:585-600.e4. [PMID: 32240601 PMCID: PMC7453618 DOI: 10.1016/j.chom.2020.03.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 11/22/2019] [Accepted: 03/10/2020] [Indexed: 12/12/2022]
Abstract
The gut microbiota has been associated with colorectal cancer (CRC), but causal alterations preceding CRC have not been elucidated. To prospectively assess microbiome changes prior to colorectal neoplasia, we investigated samples from 100 Lynch syndrome patients using 16S rRNA gene sequencing of colon biopsies, coupled with metagenomic and metatranscriptomic sequencing of feces. Colectomy and CRC history represented the largest effects on microbiome profiles. A subset of Clostridiaceae were depleted in stool corresponding with baseline adenomas, while Desulfovibrio was enriched both in stool and in mucosal biopsies. A classifier leveraging stool metatranscriptomes resulted in modest power to predict interval development of preneoplastic colonic adenoma. Predictive transcripts corresponded with a shift in flagellin contributors and oxidative metabolic microenvironment, potentially factors in local CRC pathogenesis. This suggests that the effectiveness of prospective microbiome monitoring for adenomas may be limited but supports the potential causality of these consistent, early microbial changes in colonic neoplasia.
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Affiliation(s)
- Yan Yan
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - David A Drew
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Arnold Markowitz
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jason Lloyd-Price
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Galeb Abu-Ali
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Long H Nguyen
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Christina Tran
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Daniel C Chung
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Katherine K Gilpin
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Dana Meixell
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Melanie Parziale
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Madeline Schuck
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Zalak Patel
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - James M Richter
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Peter B Kelsey
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Wendy S Garrett
- Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Immunology & Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Andrew T Chan
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| | - Zsofia K Stadler
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| | - Curtis Huttenhower
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Immunology & Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
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78
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Sanchez‐Garrido J, Slater SL, Clements A, Shenoy AR, Frankel G. Vying for the control of inflammasomes: The cytosolic frontier of enteric bacterial pathogen-host interactions. Cell Microbiol 2020; 22:e13184. [PMID: 32185892 PMCID: PMC7154749 DOI: 10.1111/cmi.13184] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 01/13/2020] [Accepted: 01/30/2020] [Indexed: 12/13/2022]
Abstract
Enteric pathogen-host interactions occur at multiple interfaces, including the intestinal epithelium and deeper organs of the immune system. Microbial ligands and activities are detected by host sensors that elicit a range of immune responses. Membrane-bound toll-like receptors and cytosolic inflammasome pathways are key signal transducers that trigger the production of pro-inflammatory molecules, such as cytokines and chemokines, and regulate cell death in response to infection. In recent years, the inflammasomes have emerged as a key frontier in the tussle between bacterial pathogens and the host. Inflammasomes are complexes that activate caspase-1 and are regulated by related caspases, such as caspase-11, -4, -5 and -8. Importantly, enteric bacterial pathogens can actively engage or evade inflammasome signalling systems. Extracellular, vacuolar and cytosolic bacteria have developed divergent strategies to subvert inflammasomes. While some pathogens take advantage of inflammasome activation (e.g. Listeria monocytogenes, Helicobacter pylori), others (e.g. E. coli, Salmonella, Shigella, Yersinia sp.) deploy a range of virulence factors, mainly type 3 secretion system effectors, that subvert or inhibit inflammasomes. In this review we focus on inflammasome pathways and their immune functions, and discuss how enteric bacterial pathogens interact with them. These studies have not only shed light on inflammasome-mediated immunity, but also the exciting area of mammalian cytosolic immune surveillance.
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Affiliation(s)
| | | | | | - Avinash R. Shenoy
- Department of Infectious Disease, MRC Centre for Molecular Bacteriology & InfectionImperial College LondonLondonUK
| | - Gad Frankel
- Department of Life SciencesImperial College LondonLondonUK
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79
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Zhang X, Arnold IC, Müller A. Mechanisms of persistence, innate immune activation and immunomodulation by the gastric pathogen Helicobacter pylori. Curr Opin Microbiol 2020; 54:1-10. [PMID: 32007716 DOI: 10.1016/j.mib.2020.01.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 01/03/2020] [Indexed: 12/20/2022]
Abstract
The gastric bacterium Helicobacter pylori efficiently evades innate immune detection and persistently colonizes its human host. Understanding the genetic determinants that H. pylori uses to establish and maintain persistence, along with their cellular targets, is key to our understanding of the pathogenesis of this extraordinarily successful bacterial colonizer of the human stomach. This review highlights recent advances in elucidating innate immune recognition of H. pylori, its interactions with myeloid cells and the consequences that this very local infection has for immune responses at extragastric sites in models of allergy, autoimmunity and parasitic infection. The human-specific, gram-negative gastric colonizer and carcinogen H. pylori represents the prototype of a persistent bacterial pathogen. It is transmitted during early childhood, typically from mother to infant, and is believed to persist in its human host from the cradle to the grave. The tremendous success of H. pylori in infecting and colonizing half of the world's population, and in continuously accompanying humans since they migrated out of Africa over 60000 years ago, can largely be attributed to its ability to manipulate the host immune system to its own advantage, and to thereby ensure its own persistence and chronicity. In his final years as an active PI, Stanley Falkow increasingly recognized the need to understand bacterial persistence strategies as a prerequisite of understanding the pathogenesis of chronic bacterial infections, and, inspired in large part by Denise Monack's work on Salmonella persistence, many of our discussions at the time revolved around this topic. Multiple labs have since made important contributions to our understanding of innate immune detection of H. pylori, the types and polarization of adaptive immune responses that ensue, the ability of H. pylori to skew such immune responses to its advantage, and its ability to manipulate the host immune system with far-reaching, even systemic consequences. This review attempts to cover some of these topics, with a particular focus on the most recent contributions by researchers in the field.
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Affiliation(s)
- Xiaozhou Zhang
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Isabelle C Arnold
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Anne Müller
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland.
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80
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Pseudomonas syringae AlgU Downregulates Flagellin Gene Expression, Helping Evade Plant Immunity. J Bacteriol 2020; 202:JB.00418-19. [PMID: 31740494 DOI: 10.1128/jb.00418-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 11/08/2019] [Indexed: 12/15/2022] Open
Abstract
Flagella power bacterial movement through liquids and over surfaces to access or avoid certain environmental conditions, ultimately increasing a cell's probability of survival and reproduction. In some cases, flagella and chemotaxis are key virulence factors enabling pathogens to gain entry and attach to suitable host tissues. However, flagella are not always beneficial; both plant and animal immune systems have evolved receptors to sense the proteins that make up flagellar filaments as signatures of bacterial infection. Microbes poorly adapted to avoid or counteract these immune functions are unlikely to be successful in host environments, and this selective pressure has driven the evolution of diverse and often redundant pathogen compensatory mechanisms. We tested the role of AlgU, the Pseudomonas extracytoplasmic function sigma factor σE/σ22 ortholog, in regulating flagellar expression in the context of Pseudomonas syringae-plant interactions. We found that AlgU is necessary for downregulating bacterial flagellin expression in planta and that this results in a corresponding reduction in plant immune elicitation. This AlgU-dependent regulation of flagellin gene expression is beneficial to bacterial growth in the course of plant infection, and eliminating the plant's ability to detect flagellin makes this AlgU-dependent function irrelevant for bacteria growing in the apoplast. Together, these results add support to an emerging model in which P. syringae AlgU functions at a key control point that serves to optimize the expression of bacterial functions during host interactions, including minimizing the expression of immune elicitors and concomitantly upregulating beneficial virulence functions.IMPORTANCE Foliar plant pathogens, like Pseudomonas syringae, adjust their physiology and behavior to facilitate host colonization and disease, but the full extent of these adaptations is not known. Plant immune systems are triggered by bacterial molecules, such as the proteins that make up flagellar filaments. In this study, we found that during plant infection, AlgU, a gene expression regulator that is responsive to external stimuli, downregulates expression of fliC, which encodes the flagellin protein, a strong elicitor of plant immune systems. This change in gene expression and resultant change in behavior correlate with reduced plant immune activation and improved P. syringae plant colonization. The results of this study demonstrate the proximate and ultimate causes of flagellar regulation in a plant-pathogen interaction.
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81
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Chidwick HS, Fascione MA. Mechanistic and structural studies into the biosynthesis of the bacterial sugar pseudaminic acid (Pse5Ac7Ac). Org Biomol Chem 2020; 18:799-809. [PMID: 31913385 DOI: 10.1039/c9ob02433f] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The non-mammalian nonulosonic acid sugar pseudaminic acid (Pse) is present on the surface of a number of human pathogens including Campylobacter jejuni and Helicobacter pylori and other bacteria such as multidrug resistant Acinetobacter baumannii. It is likely important for evasion of the host immune sysyem, and also plays a role in bacterial motility through flagellin glycosylation. Herein we review the mechanistic and structural characterisation of the enzymes responsible for the biosynthesis of the Pse parent structure, Pse5Ac7Ac in bacteria.
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82
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Fürst U, Zeng Y, Albert M, Witte AK, Fliegmann J, Felix G. Perception of Agrobacterium tumefaciens flagellin by FLS2 XL confers resistance to crown gall disease. NATURE PLANTS 2020; 6:22-27. [PMID: 31949311 DOI: 10.1038/s41477-019-0578-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
Bacterial flagella are perceived by the innate immune systems of plants1 and animals2 alike, triggering resistance. Common to higher plants is the immunoreceptor FLAGELLIN-SENSING 2 (FLS2)3, which detects flagellin via its most conserved epitope, flg22. Agrobacterium tumefaciens, which causes crown gall disease in many crop plants, has a highly diverged flg22 epitope and evades immunodetection by plants so far studied. We asked whether, as a next step in this game of 'hide and seek', there are plant species that have evolved immunoreceptors with specificity for the camouflaged flg22Atum of A. tumefaciens. In the wild grape species Vitis riparia, we discovered FLS2XL, a previously unknown form of FLS2, that provides exquisite sensitivity to typical flg22 and to flg22Atum. As exemplified by ectopic expression in tobacco, FLS2XL can limit crown gall disease caused by A. tumefaciens.
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Affiliation(s)
- Ursula Fürst
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany
| | - Yi Zeng
- The Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, USA
| | - Markus Albert
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany
| | | | - Judith Fliegmann
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany
| | - Georg Felix
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany.
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83
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Pachathundikandi SK, Tegtmeyer N, Arnold IC, Lind J, Neddermann M, Falkeis-Veits C, Chattopadhyay S, Brönstrup M, Tegge W, Hong M, Sticht H, Vieth M, Müller A, Backert S. T4SS-dependent TLR5 activation by Helicobacter pylori infection. Nat Commun 2019; 10:5717. [PMID: 31844047 PMCID: PMC6915727 DOI: 10.1038/s41467-019-13506-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 11/07/2019] [Indexed: 02/08/2023] Open
Abstract
Toll-like receptor TLR5 recognizes a conserved domain, termed D1, that is present in flagellins of several pathogenic bacteria but not in Helicobacter pylori. Highly virulent H. pylori strains possess a type IV secretion system (T4SS) for delivery of virulence factors into gastric epithelial cells. Here, we show that one of the H. pylori T4SS components, protein CagL, can act as a flagellin-independent TLR5 activator. CagL contains a D1-like motif that mediates adherence to TLR5+ epithelial cells, TLR5 activation, and downstream signaling in vitro. TLR5 expression is associated with H. pylori infection and gastric lesions in human biopsies. Using Tlr5-knockout and wild-type mice, we show that TLR5 is important for efficient control of H. pylori infection. Our results indicate that CagL, by activating TLR5, may modulate immune responses to H. pylori. Toll-like receptor TLR5 recognizes a domain, D1, that is present in flagellins of several pathogenic bacteria but not in Helicobacter pylori. Here, the authors show that TLR5 can be activated independently of flagellin by a component of the H. pylori type IV secretion system that contains a D1-like motif.
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Affiliation(s)
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | | | - Judith Lind
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Matthias Neddermann
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | | | - Sujay Chattopadhyay
- JIS Institute of Advanced Studies and Research, JIS University, Kolkata, 700091, India
| | - Mark Brönstrup
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Werner Tegge
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Minsun Hong
- Division of Biological Science and Technology, Yonsei University, Wonju, Republic of Korea
| | - Heinrich Sticht
- Institute of Biochemistry, Division of Bioinformatics, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Michael Vieth
- Institute for Pathology, Klinikum Bayreuth, Bayreuth, Germany
| | - Anne Müller
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany.
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84
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Hameed A. Human Immunity Against Campylobacter Infection. Immune Netw 2019; 19:e38. [PMID: 31921468 PMCID: PMC6943174 DOI: 10.4110/in.2019.19.e38] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/17/2019] [Accepted: 11/18/2019] [Indexed: 12/13/2022] Open
Abstract
Campylobacter is a worldwide foodborne pathogen, associated with human gastroenteritis. The efficient translocation of Campylobacter and its ability to secrete toxins into host cells are the 2 key features of Campylobacter pathophysiology which trigger inflammation in intestinal cells and contribute to the development of gastrointestinal symptoms, particularly diarrhoea, in humans. The purpose of conducting this literature review is to summarise the current understanding of: i) the human immune responses involved in the elimination of Campylobacter infection and ii) the resistance potential in Campylobacter against these immune responses. This review has highlighted that the intestinal epithelial cells are the preliminary cells which sense Campylobacter cells by means of their cell-surface and cytosolic receptors, activate various receptors-dependent signalling pathways, and recruit the innate immune cells to the site of inflammation. The innate immune system, adaptive immune system, and networking between these systems play a crucial role in bacterial clearance. Different cellular constituents of Campylobacter, mainly cell membrane lipooligosaccharides, capsule, and toxins, provide protection to Campylobacter against the human immune system mediated killing. This review has also identified gaps in knowledge, which are related to the activation of following during Campylobacter infection: i) cathelicidins, bactericidal permeability-increasing proteins, chemokines, and inflammasomes in intestinal epithelial cells; ii) siglec-7 receptors in dendritic cell; iii) acute phase proteins in serum; and iv) T-cell subsets in lymphoid nodules. This review evaluates the existing literature to improve the understanding of human immunity against Campylobacter infection and identify some of the knowledge gaps for future research.
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Affiliation(s)
- Amber Hameed
- Division of Life Sciences, University of Northampton, Northampton NN1 5PH, UK
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85
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Rapid Bladder Interleukin-10 Synthesis in Response to Uropathogenic Escherichia coli Is Part of a Defense Strategy Triggered by the Major Bacterial Flagellar Filament FliC and Contingent on TLR5. mSphere 2019; 4:4/6/e00545-19. [PMID: 31776239 PMCID: PMC6881718 DOI: 10.1128/msphere.00545-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Interleukin-10 is part of the immune response to urinary tract infection (UTI) due to E. coli, and it is important in the early control of infection in the bladder. Defining the mechanism of engagement of the immune system by the bacteria that enables the protective IL-10 response is critical to exploring how we might exploit this mechanism for new infection control strategies. In this study, we reveal part of the bacterial flagellar apparatus (FliC) is an important component that is sensed by and responsible for induction of IL-10 in the response to UPEC. We show this response occurs in a TLR5-dependent manner. Using infection prevention and control trials in mice infected with E. coli, this study also provides evidence that purified FliC might be of value in novel approaches for the treatment of UTI or in preventing infection by exploiting the FliC-triggered bladder transcriptome. Urinary tract infection (UTI) caused by uropathogenic Escherichia coli (UPEC) engages interleukin-10 (IL-10) as an early innate immune response to regulate inflammation and promote the control of bladder infection. However, the mechanism of engagement of innate immunity by UPEC that leads to elicitation of IL-10 in the bladder is unknown. Here, we identify the major UPEC flagellar filament, FliC, as a key bacterial component sensed by the bladder innate immune system responsible for the induction of IL-10 synthesis. IL-10 responses of human as well as mouse bladder epithelial cell-monocyte cocultures were triggered by flagella of three major UPEC representative strains, CFT073, UTI89, and EC958. FliC purified to homogeneity induced IL-10 in vitro and in vivo as well as other functionally related cytokines, including IL-6. The genome-wide innate immunological context of FliC-induced IL-10 in the bladder was defined using RNA sequencing that revealed a network of transcriptional and antibacterial defenses comprising 1,400 genes that were induced by FliC. Of the FliC-responsive bladder transcriptome, altered expression of il10 and 808 additional genes were dependent on Toll-like receptor 5 (TLR5), according to analysis of TLR5-deficient mice. Examination of the potential of FliC and associated innate immune signature in the bladder to boost host defense, based on prophylactic or therapeutic administration to mice, revealed significant benefits for the control of UPEC. We conclude that detection of FliC through TLR5 triggers rapid IL-10 synthesis in the bladder, and FliC represents a potential immune modulator that might offer benefit for the treatment or prevention of UPEC UTI. IMPORTANCE Interleukin-10 is part of the immune response to urinary tract infection (UTI) due to E. coli, and it is important in the early control of infection in the bladder. Defining the mechanism of engagement of the immune system by the bacteria that enables the protective IL-10 response is critical to exploring how we might exploit this mechanism for new infection control strategies. In this study, we reveal part of the bacterial flagellar apparatus (FliC) is an important component that is sensed by and responsible for induction of IL-10 in the response to UPEC. We show this response occurs in a TLR5-dependent manner. Using infection prevention and control trials in mice infected with E. coli, this study also provides evidence that purified FliC might be of value in novel approaches for the treatment of UTI or in preventing infection by exploiting the FliC-triggered bladder transcriptome.
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86
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Nawab A, An L, Wu J, Li G, Liu W, Zhao Y, Wu Q, Xiao M. Chicken toll-like receptors and their significance in immune response and disease resistance. Int Rev Immunol 2019; 38:284-306. [PMID: 31662000 DOI: 10.1080/08830185.2019.1659258] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Infectious diseases are a major challenge for the poultry industry that causes widespread production losses. Thus, management and control of poultry health and diseases are essential for the viability of the industry. Toll-like receptors are best characterized as membrane-bound receptors that perform a central role in immune homeostasis and disease resistance by recognition of pathogen-associated molecular patterns. In response to pathogen recognition, TLRs initiate both innate and adaptive immune responses which may help to develop immunomodulatory therapeutics for TLR associated diseases. Vaccination produces specific immunity in the animal's body towards pathogens. However, due to certain disadvantages of vaccines, (inactivation of attenuated pathogens into the virulent strains and weak immunogenicity of inactivated vaccines) there is a crucial need to develop the safe and effective therapeutic intervention. TLR ligands have been classified as a potential adjuvant against the infectious diseases in farm animals. TLR adjuvants induce both specific and nonspecific immune responses in chickens to combat several bacterial, viral and parasitic diseases. Therefore, the aim of this review was to explore the chicken TLR4 and their role in immune responses and disease resistance to develop disease resistance poultry breeds in future.
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Affiliation(s)
- Aamir Nawab
- Department of Animal Science, Guangdong Ocean University, Zhanjiang, Guangdong, China.,Faculty of Veterinary Medicine, PMAS- Arid Agriculture University Rawalpindi, Rawalpindi, Pakistan
| | - Lilong An
- Department of Animal Science, Guangdong Ocean University, Zhanjiang, Guangdong, China
| | - Jiang Wu
- Department of Animal Science, Guangdong Ocean University, Zhanjiang, Guangdong, China
| | - Guanghui Li
- Department of Animal Science, Guangdong Ocean University, Zhanjiang, Guangdong, China
| | - Wenchao Liu
- Department of Animal Science, Guangdong Ocean University, Zhanjiang, Guangdong, China
| | - Yi Zhao
- Department of Animal Science, Guangdong Ocean University, Zhanjiang, Guangdong, China
| | - Qimin Wu
- Mechanical and Power Engineering College, Guangdong Ocean University, Zhanjiang, Guangdong, China
| | - Mei Xiao
- Department of Animal Science, Guangdong Ocean University, Zhanjiang, Guangdong, China
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87
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Clyne M, Rowland M. The Role of Host Genetic Polymorphisms in Helicobacter pylori Mediated Disease Outcome. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1149:151-172. [PMID: 31016623 DOI: 10.1007/5584_2019_364] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The clinical outcome of infection with the chronic gastric pathogen Helicobacter pylori is not the same for all individuals and also differs in different ethnic groups. Infection occurs in early life (<3 years of age), and while all infected persons mount an immune response and develop gastritis, the majority of individuals are asymptomatic. However, up to 10-15% develop duodenal ulceration, up to 1% develop gastric cancer (GC) and up to 0.1% can develop gastric mucosa-associated lymphoid tissue (MALT) lymphoma. The initial immune response fails to clear infection and H. pylori can persist for decades. H. pylori has been classified as a group one carcinogen by the WHO. Interestingly, development of duodenal ulceration protects against GC. Factors that determine the outcome of infection include the genotype of the infecting strains and the environment. Host genetic polymorphisms have also been identified as factors that play a role in mediating the clinical outcome of infection. Several studies present compelling evidence that polymorphisms in genes involved in the immune response such as pro and anti-inflammatory cytokines and pathogen recognition receptors (PRRs) play a role in modulating disease outcome. However, as the number of studies grows emerging confounding factors are small sample size and lack of appropriate controls, lack of consideration of environmental and bacterial factors and ethnicity of the population. This chapter is a review of current evidence that host genetic polymorphisms play a role in mediating persistent H. pylori infection and the consequences of the subsequent inflammatory response.
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Affiliation(s)
- Marguerite Clyne
- School of Medicine and The Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland.
| | - Marion Rowland
- School of Medicine, University College Dublin, Dublin, Ireland
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88
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Short Chain Fatty Acids and Fecal Microbiota Abundance in Humans with Obesity: A Systematic Review and Meta-Analysis. Nutrients 2019; 11:nu11102512. [PMID: 31635264 PMCID: PMC6835694 DOI: 10.3390/nu11102512] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 10/09/2019] [Accepted: 10/17/2019] [Indexed: 12/12/2022] Open
Abstract
There have been mixed results regarding the relationship among short chain fatty acids (SCFAs), microbiota, and obesity in human studies. We selected studies that provided data on SCFA levels or fecal microbiota abundance in obese and nonobese individuals and then combined the published estimates using a random-effects meta-analysis. Obese individuals had significantly higher fecal concentrations of acetate (SMD (standardized mean differences) = 0.87, 95% CI (confidence interva) = 0.24-1.50, I2 (I-squared) = 88.5), propionate (SMD = 0.86, 95% CI = 0.35-1.36, I2 = 82.3%), and butyrate (SMD = 0.78, 95% CI = 0.29-1.27, I2 = 81.7%) than nonobese controls. The subgroup analyses showed no evidence of heterogeneity among obese individuals with a BMI >30 kg/m2 (I2 = 0.0%). At the phylum level, the abundance of fecal microbiota was reduced in obese compared to nonobese individuals, but the difference was not statistically significant (Bacteroidetes phylum, SMD = -0.36, 95% CI = -0.73-0.01; Firmicutes phylum, SMD = -0.10, 95% CI = -0.31-0.10). The currently available human case-control studies show that obesity is associated with high levels of SCFA but not gut microbiota richness at the phylum level. Additional well-designed studies with a considerable sample size are needed to clarify whether this association is causal, but it is also necessary to identify additional contributors to SCFA production, absorption, and excretion in humans.
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89
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D Y Bandara YMN, Tang J, Saharia J, Rogowski LW, Ahn CW, Kim MJ. Characterization of Flagellar Filaments and Flagellin through Optical Microscopy and Label-Free Nanopore Responsiveness. Anal Chem 2019; 91:13665-13674. [PMID: 31525946 DOI: 10.1021/acs.analchem.9b02874] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In this study, we investigated the translocation characteristics of flagellar filaments (Salmonella typhimurium) and flagellin subunits through silicon nitride nanopores in tandem with optical microscopy analysis. Even though untagged flagella are dark to the optical method, the label-free nature of the nanopore sensor allows it to characterize both tagged (Cy3) and pristine forms of flagella (including real-time developments). Flagella were depolymerized to flagellin subunits at ∼65 °C (most commonly reported temperature), ∼70 °C, ∼75 °C, and ∼80 °C to investigate the effect of temperature (Tdepol) on depolymerization. The change in conductance (ΔG) profiles corresponding to Tdepol ∼65 °C and ∼70 °C were bracketed within the flagellin monomer profile whereas those of ∼75 °C and ∼80 °C extended beyond this profile, suggesting a change to the native protein state. The molecular radius calculated from the excluded electrolyte volume of flagellin through nanopore-based ΔG characteristics for each Tdepol of ∼65 °C, ∼70 °C, ∼75 °C, and ∼80 °C yielded ∼4.2 ± 0.2 nm, ∼4.3 ± 0.3 nm, ∼4.1 ± 0.2 nm, and ∼4.7 ± 0.5 nm, respectively. This, along with ΔG (plateaued values) and translocation time profiles, points to the possibility of flagellin misfolding at ∼80 °C.
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Affiliation(s)
- Y M Nuwan D Y Bandara
- Department of Mechanical Engineering , Southern Methodist University , Dallas , Texas 75275 , United States
| | - Jiannan Tang
- Department of Mechanical Engineering , Southern Methodist University , Dallas , Texas 75275 , United States
| | - Jugal Saharia
- Department of Mechanical Engineering , Southern Methodist University , Dallas , Texas 75275 , United States
| | - Louis William Rogowski
- Department of Mechanical Engineering , Southern Methodist University , Dallas , Texas 75275 , United States
| | - Chi Won Ahn
- Nano-Materials Laboratory , National NanoFab Center , Daejeon 34141 , Republic of Korea
| | - Min Jun Kim
- Department of Mechanical Engineering , Southern Methodist University , Dallas , Texas 75275 , United States
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90
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Nakamoto K, Watanabe M, Sada M, Inui T, Nakamura M, Honda K, Wada H, Ishii H, Takizawa H. Pseudomonas aeruginosa-derived flagellin stimulates IL-6 and IL-8 production in human bronchial epithelial cells: A potential mechanism for progression and exacerbation of COPD. Exp Lung Res 2019; 45:255-266. [PMID: 31517562 DOI: 10.1080/01902148.2019.1665147] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Background and purpose of the study: Pseudomonas aeruginosa commonly colonizes the airway of patients with chronic obstructive pulmonary disease (COPD) and exacerbates their symptoms. P. aeruginosa carries flagellin that stimulates toll-like receptor (TLR)-5; however, the role of flagellin in the pathogenesis of COPD remains unclear. The aim of the study was to evaluate the mechanisms of the flagellin-induced innate immune response in bronchial epithelial cells, and to assess the effects of anti-inflammatory agents for treatment. Materials and methods: We stimulated BEAS-2B cells with P. aeruginosa-derived flagellin, and assessed mRNA expression and protein secretion of interleukin (IL)-6 and IL-8. We also used mitogen-activated protein kinases (MAPK) inhibitors to assess the signaling pathways involved in flagellin stimulation, and investigated the effect of clinically available anti-inflammatory agents against flagellin-induced inflammation. Results: Flagellin promoted protein and mRNA expression of IL-6 and IL-8 in BEAS-2B cells and induced phosphorylation of p38, ERK, and JNK; p38 phosphorylation-induced IL-6 production, while IL-8 production resulted from p38 and ERK phosphorylation. Fluticasone propionate (FP) and dexamethasone (DEX) suppressed IL-6 and IL-8 production in BEAS-2B cells, but clarithromycin (CAM) failed to do so. Conclusions: P. aeruginosa-derived flagellin-induced IL-6 and IL-8 production in bronchial epithelial cells, which partially explains the mechanisms of progression and exacerbation of COPD. Corticosteroids are the most effective treatment for the suppression of flagellin-induced IL-6 and IL-8 production in the bronchial epithelial cells.
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Affiliation(s)
- Keitaro Nakamoto
- Department of Respiratory Medicine, Kyorin University School of Medicine , Tokyo , Japan
| | - Masato Watanabe
- Department of Respiratory Medicine, Kyorin University School of Medicine , Tokyo , Japan
| | - Mitsuru Sada
- Department of Respiratory Medicine, Kyorin University School of Medicine , Tokyo , Japan
| | - Toshiya Inui
- Department of Respiratory Medicine, Kyorin University School of Medicine , Tokyo , Japan
| | - Masuo Nakamura
- Department of Respiratory Medicine, Kyorin University School of Medicine , Tokyo , Japan
| | - Kojiro Honda
- Department of Respiratory Medicine, Kyorin University School of Medicine , Tokyo , Japan
| | - Hiroo Wada
- Department of Respiratory Medicine, Kyorin University School of Medicine , Tokyo , Japan
| | - Haruyuki Ishii
- Department of Respiratory Medicine, Kyorin University School of Medicine , Tokyo , Japan
| | - Hajime Takizawa
- Department of Respiratory Medicine, Kyorin University School of Medicine , Tokyo , Japan
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91
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Xu M, Xie Y, Tan M, Zheng K, Xiao Y, Jiang C, Zhao F, Zeng T, Wu Y. The N-terminal D1 domain of Treponema pallidum flagellin binding to TLR5 is required but not sufficient in activation of TLR5. J Cell Mol Med 2019; 23:7490-7504. [PMID: 31493340 PMCID: PMC6815820 DOI: 10.1111/jcmm.14617] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 08/02/2019] [Accepted: 08/09/2019] [Indexed: 12/18/2022] Open
Abstract
Syphilis is a chronic bacterial infection caused by Treponema pallidum (T pallidum) and the pathogenesis that T pallidum infection induces immunopathological damages in skin and other tissues remains unclear. We have previously reported that recombinant flagellins of T pallidum can elicit IL‐6 and IL‐8 transcriptions via TLR5 pathway. To identify the domains which induced the pro‐inflammatory activity and the importance of the interactions between TLR5 and domains, homology‐based modelling and comparative structural analyses revealed that Tpflagellins can combine with TLR5 directly. Deletion mutations showed that the ND1 domain binding to TLR5 is required but not sufficient in TLR5 activation. Moreover, site‐directed mutagenesis analysis indicated that the arginine residue (Tpflagellins R89) of the ND1 domain and its adjacent residues (Tpflagellins L93 and E113) constitute a hot spot that elicits IL‐6, IL‐8 transcriptions and TLR5 activation, and affects the binding of Tpflagellins to TLR5. Taken together, these results give insight into the pathogenesis of T pallidum and may contribute to the future design of Tpflagellins‐based therapeutics and syphilis vaccine.
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Affiliation(s)
- Man Xu
- Institution of Pathogenic Biology, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Yafeng Xie
- Institution of Pathogenic Biology, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China.,Department of Clinical Laboratory, The Second Affiliated Hospital of University of South China, Hengyang, China
| | - Manyi Tan
- Hunan Provincial Center for Disease Control and Prevention, Changsha, China
| | - Kang Zheng
- Institution of Pathogenic Biology, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Yongjian Xiao
- Department of Clinical Laboratory, The Second Affiliated Hospital of University of South China, Hengyang, China
| | - Chuanhao Jiang
- Department of Laboratory Medicine, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Feijun Zhao
- Institution of Pathogenic Biology, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Tiebing Zeng
- Institution of Pathogenic Biology, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Yimou Wu
- Institution of Pathogenic Biology, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
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92
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Dickson K, Lehmann C. Inflammatory Response to Different Toxins in Experimental Sepsis Models. Int J Mol Sci 2019; 20:ijms20184341. [PMID: 31491842 PMCID: PMC6770119 DOI: 10.3390/ijms20184341] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/27/2019] [Accepted: 09/02/2019] [Indexed: 12/29/2022] Open
Abstract
Sepsis is defined as life-threatening organ dysfunction caused by the dysregulated host response to infection. Despite serious mortality and morbidity, no sepsis-specific drugs exist. Endotoxemia is often used to model the hyperinflammation associated with early sepsis. This model classically uses lipopolysaccharide (LPS) from Gram-negative pathogens to activate the immune system, leading to hyperinflammation, microcirculatory disturbances and death. Other toxins may also be used to activate the immune system including Gram-positive peptidoglycan (PG) and lipoteichoic acid (LTA). In addition to these standard toxins, other bacterial components can induce inflammation. These molecules activate different signaling pathways and produce different physiological responses which can be taken advantage of for sepsis modeling. Endotoxemia modeling can provide information on pathways to inflammation in sepsis and contribute to preclinical drug development.
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Affiliation(s)
- Kayle Dickson
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
| | - Christian Lehmann
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS B3H 4R2, Canada.
- Department of Pharmacology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
- Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada.
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93
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López-Yglesias AH, Lu CC, Zhao X, Chou T, VandenBos T, Strong RK, Smith KD. FliC's Hypervariable D3 Domain Is Required for Robust Anti-Flagellin Primary Antibody Responses. Immunohorizons 2019; 3:422-432. [PMID: 31488506 DOI: 10.4049/immunohorizons.1800061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 08/13/2019] [Indexed: 11/19/2022] Open
Abstract
Bacterial flagellin is a well-known agonist of the innate immune system that induces proinflammatory responses through the TLR5 and Naip5/6 recognition pathways. Several clinical trials investigating flagellin fusion proteins have demonstrated promising results for inducing protective immunity toward influenza virus, which has been largely attributed to flagellin's ability to activate TLR5. Our laboratory previously demonstrated that the Salmonella enterica serovar Typhimurium flagellin protein, FliC, induces Ab responses in mice through a third pathway that is independent of TLR5, Casp1/11, and MyD88. In this study, we further define the structural features of FliC that contribute to this unknown third pathway. By destroying the Naip5/6 and TLR5 recognition sites, we demonstrate that neither were required for the TLR5-, inflammasome- and MyD88-independent Ab responses toward FliC. In contrast, deletion of FliC's D3 or D0/D1 domains eliminated primary anti-flagellin Ab responses. For optimal primary and secondary anti-flagellin Ab responses we show that TLR5, inflammasome recognition, and the D3 domain of FliC are essential for flagellin's robust immunogenicity. Our data demonstrate that the D3 domain of FliC influences immunogenicity independent of the known innate recognition sites in the D0/D1 domains to augment Ab production. Our results suggest full-length FliC is critical for optimal immunogenicity and Ab responses in flagellin-based vaccines.
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Affiliation(s)
| | - Chun-Chi Lu
- Department of Pathology, University of Washington, Seattle, WA 98195; and
| | - Xiaodan Zhao
- Department of Pathology, University of Washington, Seattle, WA 98195; and
| | - Tiffany Chou
- Department of Pathology, University of Washington, Seattle, WA 98195; and
| | - Tim VandenBos
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Roland K Strong
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Kelly D Smith
- Department of Pathology, University of Washington, Seattle, WA 98195; and
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94
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Burnham PM, Hendrixson DR. Campylobacter jejuni: collective components promoting a successful enteric lifestyle. Nat Rev Microbiol 2019; 16:551-565. [PMID: 29892020 DOI: 10.1038/s41579-018-0037-9] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Campylobacter jejuni is the leading cause of bacterial diarrhoeal disease in many areas of the world. The high incidence of sporadic cases of disease in humans is largely due to its prevalence as a zoonotic agent in animals, both in agriculture and in the wild. Compared with many other enteric bacterial pathogens, C. jejuni has strict growth and nutritional requirements and lacks many virulence and colonization determinants that are typically used by bacterial pathogens to infect hosts. Instead, C. jejuni has a different collection of factors and pathways not typically associated together in enteric pathogens to establish commensalism in many animal hosts and to promote diarrhoeal disease in the human population. In this Review, we discuss the cellular architecture and structure of C. jejuni, intraspecies genotypic variation, the multiple roles of the flagellum, specific nutritional and environmental growth requirements and how these factors contribute to in vivo growth in human and avian hosts, persistent colonization and pathogenesis of diarrhoeal disease.
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Affiliation(s)
- Peter M Burnham
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - David R Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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95
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The Vertebrate TLR Supergene Family Evolved Dynamically by Gene Gain/Loss and Positive Selection Revealing a Host–Pathogen Arms Race in Birds. DIVERSITY-BASEL 2019. [DOI: 10.3390/d11080131] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The vertebrate toll-like receptor (TLRs) supergene family is a first-line immune defense against viral and non-viral pathogens. Here, comparative evolutionary-genomics of 79 vertebrate species (8 mammals, 48 birds, 11 reptiles, 1 amphibian, and 11 fishes) revealed differential gain/loss of 26 TLRs, including 6 (TLR3, TLR7, TLR8, TLR14, TLR21, and TLR22) that originated early in vertebrate evolution before the diversification of Agnatha and Gnathostomata. Subsequent dynamic gene gain/loss led to lineage-specific diversification with TLR repertoires ranging from 8 subfamilies in birds to 20 in fishes. Lineage-specific loss of TLR8-9 and TLR13 in birds and gains of TLR6 and TLR10-12 in mammals and TLR19-20 and TLR23-27 in fishes. Among avian species, 5–10% of the sites were under positive selection (PS) (omega 1.5–2.5) with radical amino-acid changes likely affecting TLR structure/functionality. In non-viral TLR4 the 20 PS sites (posterior probability PP > 0.99) likely increased ability to cope with diversified ligands (e.g., lipopolysaccharide and lipoteichoic). For viral TLR7, 23 PS sites (PP > 0.99) possibly improved recognition of highly variable viral ssRNAs. Rapid evolution of the TLR supergene family reflects the host–pathogen arms race and the coevolution of ligands/receptors, which follows the premise that birds have been important vectors of zoonotic pathogens and reservoirs for viruses.
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96
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Udgata A, Dolasia K, Ghosh S, Mukhopadhyay S. Dribbling through the host defence: targeting the TLRs by pathogens. Crit Rev Microbiol 2019; 45:354-368. [DOI: 10.1080/1040841x.2019.1608904] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Atul Udgata
- Laboratory of Molecular Cell Biology, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India
- Manipal Academy of Higher Education, Manipal, India
| | - Komal Dolasia
- Laboratory of Molecular Cell Biology, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India
- Manipal Academy of Higher Education, Manipal, India
| | - Sudip Ghosh
- Molecular Biology Division, ICMR-National Institute of Nutrition, Hyderabad, India
| | - Sangita Mukhopadhyay
- Laboratory of Molecular Cell Biology, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India
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Steimle A, Menz S, Bender A, Ball B, Weber ANR, Hagemann T, Lange A, Maerz JK, Parusel R, Michaelis L, Schäfer A, Yao H, Löw HC, Beier S, Tesfazgi Mebrhatu M, Gronbach K, Wagner S, Voehringer D, Schaller M, Fehrenbacher B, Autenrieth IB, Oelschlaeger TA, Frick JS. Flagellin hypervariable region determines symbiotic properties of commensal Escherichia coli strains. PLoS Biol 2019; 17:e3000334. [PMID: 31206517 PMCID: PMC6597123 DOI: 10.1371/journal.pbio.3000334] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 06/27/2019] [Accepted: 06/05/2019] [Indexed: 12/19/2022] Open
Abstract
Escherichia coli represents a classical intestinal gram-negative commensal. Despite this commensalism, different E. coli strains can mediate disparate immunogenic properties in a given host. Symbiotic E. coli strains such as E. coli Nissle 1917 (EcN) are attributed beneficial properties, e.g., promotion of intestinal homeostasis. Therefore, we aimed to identify molecular features derived from symbiotic bacteria that might help to develop innovative therapeutic alternatives for the treatment of intestinal immune disorders. This study was performed using the dextran sodium sulphate (DSS)-induced colitis mouse model, which is routinely used to evaluate potential therapeutics for the treatment of Inflammatory Bowel Diseases (IBDs). We focused on the analysis of flagellin structures of different E. coli strains. EcN flagellin was found to harbor a substantially longer hypervariable region (HVR) compared to other commensal E. coli strains, and this longer HVR mediated symbiotic properties through stronger activation of Toll-like receptor (TLR)5, thereby resulting in interleukin (IL)-22–mediated protection of mice against DSS-induced colitis. Furthermore, using bone-marrow–chimeric mice (BMCM), CD11c+ cells of the colonic lamina propria (LP) were identified as the main mediators of these flagellin-induced symbiotic effects. We propose flagellin from symbiotic E. coli strains as a potential therapeutic to restore intestinal immune homeostasis, e.g., for the treatment of IBD patients. A flagellum renders bacteria motile, but this study reveals another property important for symbiosis: the hypervariable region of Escherichia coli flagellin strongly determines activation of TLR5, mediating benefits for the host such as protection against colitis.
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Affiliation(s)
- Alex Steimle
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Sarah Menz
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Annika Bender
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Brianna Ball
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | | | - Thomas Hagemann
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Anna Lange
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Jan K. Maerz
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Raphael Parusel
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Lena Michaelis
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Andrea Schäfer
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Hans Yao
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Hanna-Christine Löw
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Sina Beier
- Chair of Algorithms in Bioinformatics, Faculty of Computer Science, University of Tübingen, Tübingen, Germany
| | - Mehari Tesfazgi Mebrhatu
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Kerstin Gronbach
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Samuel Wagner
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - David Voehringer
- Department of Infection Biology, University Hospital Erlangen, Erlangen, Germany
| | - Martin Schaller
- Department of Dermatology, University Hospital Tübingen, Tübingen, Germany
| | | | - Ingo B. Autenrieth
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | | | - Julia-Stefanie Frick
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, Tübingen, Germany
- * E-mail:
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98
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Głowacka P, Żakowska D, Naylor K, Niemcewicz M, Bielawska-Drózd A. Brucella - Virulence Factors, Pathogenesis and Treatment. Pol J Microbiol 2019; 67:151-161. [PMID: 30015453 PMCID: PMC7256693 DOI: 10.21307/pjm-2018-029] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2018] [Indexed: 12/27/2022] Open
Abstract
Brucellae are Gram-negative, small rods infecting mammals and capable of causing disease called brucellosis. The infection results in abortion and sterility in domestic animals (sheeps, pigs, rams etc). Especially dangerous for humans are: Brucella melitensis, Brucella suis, Brucella abortus, and Brucella canis that trigger unspecific symptoms (flu-like manifestation). Brucella rods are introduced via host cells, by inhalation, skin abrasions, ingestion or mucosal membranes. The most important feature of Brucella is the ability to survive and multiply within both phagocytic and non-phagocytic cells. Brucella does not produce classical virulence factors: exotoxin, cytolisins, exoenzymes, plasmids, fimbria, and drug resistant forms. Major virulence factors are: lipopolysaccharide (LPS), T4SS secretion system and BvrR/BvrS system, which allow interaction with host cell surface, formation of an early, late BCV (Brucella Containing Vacuole) and interaction with endoplasmic reticulum (ER) when the bacteria multiply. The treatment of brucellosis is based on two-drug therapy, the most common combinations of antibiotics are: doxycycline with rifampicin or fluoroquinolones with rifampicin. Currently, also other methods are used to disrupt Brucella intracellular replication (tauroursodeoxycholic acid or ginseng saponin fraction A).
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Affiliation(s)
- Patrycja Głowacka
- Biological Threats Identification and Countermeasure Center of the General Karol Kaczkowski Military Institute of Hygiene and Epidemiology,Puławy,Poland
| | - Dorota Żakowska
- Biological Threats Identification and Countermeasure Center of the General Karol Kaczkowski Military Institute of Hygiene and Epidemiology,Puławy,Poland
| | - Katarzyna Naylor
- Lublin Medical University, Department of Didactics and Medical Simulation,Lublin,Poland
| | - Marcin Niemcewicz
- Biological Threats Identification and Countermeasure Center of the General Karol Kaczkowski Military Institute of Hygiene and Epidemiology,Puławy,Poland
| | - Agata Bielawska-Drózd
- Biological Threats Identification and Countermeasure Center of the General Karol Kaczkowski Military Institute of Hygiene and Epidemiology,Puławy,Poland
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99
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Morimoto N, Kondo M, Kono T, Sakai M, Hikima JI. Nonconservation of TLR5 activation site in Edwardsiella tarda flagellin decreases expression of interleukin-1β and NF-κB genes in Japanese flounder, Paralichthys olivaceus. FISH & SHELLFISH IMMUNOLOGY 2019; 87:765-771. [PMID: 30776541 DOI: 10.1016/j.fsi.2019.02.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 02/04/2019] [Accepted: 02/14/2019] [Indexed: 06/09/2023]
Abstract
Flagellin is the subunit protein that composes bacterial flagella and is recognized by toll-like receptor 5 (TLR5) as a ligand. Flagellin protein (e.g., FliC and FlaA) contains the D1, D2, and D3 domains; the D1 domain is important for recognition by TLR5 for activation of the innate immune system. In teleosts, there are two types of TLR5, the membrane form (TLR5M) and soluble form (TLR5S), the latter of which is not present in mammals. In this study, the potential of flagellin from Edwardsiella tarda (EtFliC) to induce inflammation-related genes interleukin (IL)-1β and NF-κB-p65 through TLR5S in Japanese flounder (Paralichthys olivaceus) was elucidated. A transient overexpression system was developed in flounder natural embryonic (HINAE) cells using constructs encoding two flagellin genes derived from E. tarda (pEtFliC) and Escherichia coli (pEcoFliC) and the flounder TLR5S gene (pPoTLR5S). Expression of inflammation-related genes in EtFliC- and PoTLR5S-overexpressing HINAE cells was significantly lower than in EcoFliC- and PoTLR5S-overexpressing cells. To clarify the difference between EtFliC and EcoFliC potency, the amino acid sequence of EtFliC was compared with that of other bacterial flagellin. The 91st arginine residue, known as the mammalian TLR5 activation site, was conserved in the flagellin of E. coli and other bacteria but not in EtFliC. To reveal the importance of the 91st arginine residue in FliC, a pEtFliC construct in which the 91st asparagine was mutated to arginine (pEtFliC_N91R) was generated. Expression of the IL-1β and NF-κB-p65 genes in the HINAE cells co-transfected with pEtFliC_N91R and pPoTLR5S was significantly higher than that in cells co-transfected with pEtFliC and pPoTLR5S. The results suggested that the 91st arginine residue of bacterial flagellin is involved in inflammatory response through TLR5S in teleosts. Thus, EtFliC improved by site-directed mutagenesis could be an effective adjuvant against E. tarda infection in Japanese flounder.
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Affiliation(s)
- Natsuki Morimoto
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki, 889-2192, Japan
| | - Masakazu Kondo
- Department of Applied Aquabiology, National Fisheries University, Shimonoseki, Yamaguchi, 759-6595, Japan
| | - Tomoya Kono
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki, 889-2192, Japan
| | - Masahiro Sakai
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki, 889-2192, Japan
| | - Jun-Ichi Hikima
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki, 889-2192, Japan.
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100
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Garcia-Quintanilla M, Dichter AA, Guerra H, Kempf VAJ. Carrion's disease: more than a neglected disease. Parasit Vectors 2019; 12:141. [PMID: 30909982 PMCID: PMC6434794 DOI: 10.1186/s13071-019-3390-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/07/2019] [Indexed: 01/30/2023] Open
Abstract
Infections with Bartonella bacilliformis result in Carrion's disease in humans. In the first phase of infection, the pathogen causes a hemolytic fever ("Oroya fever") with case-fatality rates as high as ~90% in untreated patients, followed by a chronical phase resulting in angiogenic skin lesions ("verruga peruana"). Bartonella bacilliformis is endemic to South American Andean valleys and is transmitted via sand flies (Lutzomyia spp.). Humans are the only known reservoir for this old disease and therefore no animal infection model is available. In the present review, we provide the current knowledge on B. bacilliformis and its pathogenicity factors, vectors, possible unknown reservoirs, established and potential infection models and immunological aspects of the disease.
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Affiliation(s)
- Meritxell Garcia-Quintanilla
- University Hospital, Goethe-University, Institute for Medical Microbiology and Infection Control, Frankfurt am Main, Germany
| | - Alexander A Dichter
- University Hospital, Goethe-University, Institute for Medical Microbiology and Infection Control, Frankfurt am Main, Germany
| | - Humberto Guerra
- Universidad Peruana Cayetano Heredia and the Instituto de Medicina Tropical Alexander von Humboldt, Lima, Peru
| | - Volkhard A J Kempf
- University Hospital, Goethe-University, Institute for Medical Microbiology and Infection Control, Frankfurt am Main, Germany.
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