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Bonhomme D, Werts C. Host and Species-Specificities of Pattern Recognition Receptors Upon Infection With Leptospira interrogans. Front Cell Infect Microbiol 2022; 12:932137. [PMID: 35937697 PMCID: PMC9353586 DOI: 10.3389/fcimb.2022.932137] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/24/2022] [Indexed: 12/12/2022] Open
Abstract
Leptospirosis is a zoonotic infectious disease affecting all vertebrates. It is caused by species of the genus Leptospira, among which are the highly pathogenic L. interrogans. Different mammals can be either resistant or susceptible to the disease which can present a large variety of symptoms. Humans are mostly asymptomatic after infection but can have in some cases symptoms varying from a flu-like syndrome to more severe forms such as Weil's disease, potentially leading to multiorgan failure and death. Similarly, cattle, pigs, and horses can suffer from acute forms of the disease, including morbidity, abortion, and uveitis. On the other hand, mice and rats are resistant to leptospirosis despite chronical colonization of the kidneys, excreting leptospires in urine and contributing to the transmission of the bacteria. To this date, the immune mechanisms that determine the severity of the infection and that confer susceptibility to leptospirosis remain enigmatic. To our interest, differential immune sensing of leptospires through the activation of or escape from pattern recognition receptors (PRRs) by microbe-associated molecular patterns (MAMPs) has recently been described. In this review, we will summarize these findings that suggest that in various hosts, leptospires differentially escape recognition by some Toll-like and NOD-like receptors, including TLR4, TLR5, and NOD1, although TLR2 and NLRP3 responses are conserved independently of the host. Overall, we hypothesize that these innate immune mechanisms could play a role in determining host susceptibility to leptospirosis and suggest a central, yet complex, role for TLR4.
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Affiliation(s)
| | - Catherine Werts
- Institut Pasteur, Université de Paris, CNRS UMR2001, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, France
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Tombácz K, Burgess G, Holder A, Werners A, Werling D. Toxoplasma gondii profilin does not stimulate an innate immune response through bovine or human TLR5. Innate Immun 2018; 24:422-429. [PMID: 30196747 PMCID: PMC6830871 DOI: 10.1177/1753425918798450] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Toxoplasma gondii is responsible for one of the most prevalent infections in people. T. gondii profilin (TgPr) is a protein integral to parasite movement and cellular invasion. Murine TLRs has been described to bind TgPr. Furthermore, more recently, human TLR5 has been described to recognise recombinant TgPr, as well as bacterial flagellin. In addition to infections in humans, T. gondii infects farm animals, but little information is available about its innate recognition. We aimed to investigate whether, similarly to their human orthologue, bovine and porcine TLR5 could also be stimulated by TgPr by using a combination of reporter cell lines expressing full length TLR5 from each species as well as primary cells. Although human and bovine TLR5-transfected cells responded to flagellin, no response was detected upon stimulation with profilin. Furthermore, TgPr failed to elicit IL-6 secretion in human peripheral blood mononuclear cells and CD14+ monocytes. In contrast, exposure of RAW cells, known to express TLR11, to TgPr slightly increased the IL-6 response. Our data cast doubts on the possibility that profilin is a specific ligand for human TLR5 and bovine TLR5. This leaves the immunogenic properties of this potential target antigen (Ag) uncharacterised outside of the murine system.
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Affiliation(s)
- Kata Tombácz
- 1 Department of Pathology and Pathogen Biology, The Royal Veterinary College, University of London, UK
| | - Gregg Burgess
- 1 Department of Pathology and Pathogen Biology, The Royal Veterinary College, University of London, UK
| | - Angela Holder
- 1 Department of Pathology and Pathogen Biology, The Royal Veterinary College, University of London, UK
| | - Arno Werners
- 2 Department of Anatomy, Physiology and Pharmacology, School of Veterinary Medicine, St. George's University, Grenada, West Indies
| | - Dirk Werling
- 1 Department of Pathology and Pathogen Biology, The Royal Veterinary College, University of London, UK
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Faber E, Tedin K, Speidel Y, Brinkmann MM, Josenhans C. Functional expression of TLR5 of different vertebrate species and diversification in intestinal pathogen recognition. Sci Rep 2018; 8:11287. [PMID: 30050158 PMCID: PMC6062626 DOI: 10.1038/s41598-018-29371-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 07/10/2018] [Indexed: 12/12/2022] Open
Abstract
Toll-like receptor 5 (TLR5) is activated by bacterial flagellins and plays a crucial role in the first-line defence against pathogenic bacteria and in immune homeostasis, and is highly conserved in vertebrate species. However, little comparative information is available on TLR5 functionality. In this study, we compared TLR5 activation using full-length and chimeric TLR5 of various vertebrate species (human, chicken, mouse, pig, cattle). Chimeric TLR5 receptors, consisting of human transmembrane and intracellular domains, linked to extracellular domains of animal origin, were generated and expressed. The comparison of chimeric TLR5s and their full-length counterparts revealed significant functional disparities. While porcine and chicken full-length TLR5s showed a strongly reduced functionality in human cells, all chimeric receptors were functional when challenged with TLR5 ligand Salmonella FliC. Using chimeric receptors as a tool allowed for the identification of ectodomain-dependent activation potential and partially host species-specific differences in response to various enteric bacterial strains and their purified flagellins. We conclude that both the extra- and intracellular determinants of TLR5 receptors are crucial for compatibility with the species expression background and hence for proper receptor functionality. TLR5 receptors with a common intracellular domain provide a useful system to investigate bacteria- and host-specific differences in receptor activation.
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Affiliation(s)
- Eugenia Faber
- Medizinische Hochschule Hannover, Institute for Medical Microbiology, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany.,DZIF-German Center for Infection Research, Partner site Hannover-Braunschweig, Hannover, Germany
| | - Karsten Tedin
- Institute of Microbiology and Epizootics, Free University Berlin, Robert-von-Ostertag-Strasse 7-13, 14163, Berlin, Germany
| | - Yvonne Speidel
- Medizinische Hochschule Hannover, Institute for Medical Microbiology, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany.,DZIF-German Center for Infection Research, Partner site Hannover-Braunschweig, Hannover, Germany
| | - Melanie M Brinkmann
- Helmholtz Center for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
| | - Christine Josenhans
- Medizinische Hochschule Hannover, Institute for Medical Microbiology, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany. .,DZIF-German Center for Infection Research, Partner site Hannover-Braunschweig, Hannover, Germany. .,Max von Pettenkofer Institute, Ludwig Maximilians University Munich, Pettenkoferstrasse 9a, 80336, Munich, Germany.
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Tahoun A, Jensen K, Corripio-Miyar Y, McAteer S, Smith DGE, McNeilly TN, Gally DL, Glass EJ. Host species adaptation of TLR5 signalling and flagellin recognition. Sci Rep 2017; 7:17677. [PMID: 29247203 PMCID: PMC5732158 DOI: 10.1038/s41598-017-17935-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 11/30/2017] [Indexed: 12/23/2022] Open
Abstract
Toll-like receptor 5 (TLR5) recognition of flagellin instigates inflammatory signalling. Significant sequence variation in TLR5 exists between animal species but its impact on activity is less well understood. Building on our previous research that bovine TLR5 (bTLR5) is functional, we compared human and bovine TLR5 activity and signalling in cognate cell lines. bTLR5 induced higher levels of CXCL8 when expressed in bovine cells and reciprocal results were found for human TLR5 (hTLR5) in human cells, indicative of host cell specificity in this response. Analysis of Toll/interleukin-1 receptor (TIR) sequences indicated that these differential responses involve cognate MyD88 recognition. siRNA knockdowns and inhibitor experiments demonstrated that there are some host differences in signalling. Although, PI3K activation is required for bTLR5 signalling, mutating bTLR5 F798 to hTLR5 Y798 within a putative PI3K motif resulted in a significantly reduced response. All ruminants have F798 in contrast to most other species, suggesting that TLR5 signalling has evolved differently in ruminants. Evolutionary divergence between bovine and human TLR5 was also apparent in relation to responses measured to diverse bacterial flagellins. Our results underscore the importance of species specific studies and how differences may alter efficacy of TLR-based vaccine adjuvants.
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Affiliation(s)
- Amin Tahoun
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.,Faculty of Veterinary Medicine, Kafrelsheikh University, 33516, Kafr el-Sheikh, Egypt
| | - Kirsty Jensen
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Yolanda Corripio-Miyar
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.,Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 OPZ, UK
| | - Sean McAteer
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - David G E Smith
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 OPZ, UK.,University of Glasgow, Glasgow, G12 8TA, UK.,Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK
| | - Tom N McNeilly
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 OPZ, UK
| | - David L Gally
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Elizabeth J Glass
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
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Bacterial flagellin-a potent immunomodulatory agent. Exp Mol Med 2017; 49:e373. [PMID: 28860663 PMCID: PMC5628280 DOI: 10.1038/emm.2017.172] [Citation(s) in RCA: 202] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 04/23/2017] [Accepted: 05/01/2017] [Indexed: 01/07/2023] Open
Abstract
Flagellin is a subunit protein of the flagellum, a whip-like appendage that enables bacterial motility. Traditionally, flagellin was viewed as a virulence factor that contributes to the adhesion and invasion of host cells, but now it has emerged as a potent immune activator, shaping both the innate and adaptive arms of immunity during microbial infections. In this review, we summarize our understanding of bacterial flagellin and host immune system interactions and the role flagellin as an adjuvant, anti-tumor and radioprotective agent, and we address important areas of future research interests.
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Osvaldova A, Stepanova H, Faldyna M, Matiasovic J. Gene expression values of pattern-recognition receptors in porcine leukocytes and their response to Salmonella enterica serovar Typhimurium infection. Res Vet Sci 2017; 114:31-35. [PMID: 28285125 DOI: 10.1016/j.rvsc.2017.02.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 02/01/2017] [Accepted: 02/28/2017] [Indexed: 11/26/2022]
Abstract
Pattern-recognition receptors (PRRs) recognize pathogen-associated molecular patterns and play an important role in triggering innate immune responses. PRRs distribution and function is well documented in mice and humans, but studies in pigs are scarce. Salmonella enterica serovar Typhimurium is common pathogen found in pigs and was used as a model for interaction with PRRs. This study investigated expression of PRRs in porcine leukocyte subpopulations at the mRNA level. Eight subpopulations of leukocytes comprising NK cells, Th, Tc, double positive T cells and γδ T cells, B cells, monocytes and neutrophils were sorted, and the expression of 12 PRRs was measured, including selected Toll-like receptors and their co-receptors, NOD-like receptor NOD2, RP-105, CD14, and dectin. The highest expression rates of most PRRs were observed in monocytes and neutrophils. The B cells expressed high levels of TLR1, TLR6, TLR9, TLR10, and RP-105. Only monocytes and γδ T cells were found to respond to Salmonella enterica serovar Typhimurium infection by intensification of PRRs expression. In Th and B cells, PRRs mRNA down-regulation was detected after infection.
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Affiliation(s)
- Alena Osvaldova
- Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic; Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences Brno, Palackého 1/3, 612 42 Brno, Czech Republic
| | - Hana Stepanova
- Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic
| | - Martin Faldyna
- Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic
| | - Jan Matiasovic
- Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic.
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Determination of Genetic Variations of Toll-Like Receptor (TLR) 2, 4, and 6 with Next-Generation Sequencing in Native Cattle Breeds of Anatolia and Holstein Friesian. DIVERSITY-BASEL 2016. [DOI: 10.3390/d8040023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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