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Druffner SR, Venkateshwaraprabu S, Khadka S, Duncan BC, Morris MT, Sen-Kilic E, Damron FH, Liechti GW, Busada JT. Comparison of gastric inflammation and metaplasia induced by Helicobacter pylori or Helicobacter felis colonization in mice. Microbiol Spectr 2024:e0001524. [PMID: 38682907 DOI: 10.1128/spectrum.00015-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 03/18/2024] [Indexed: 05/01/2024] Open
Abstract
Gastric cancer is the fifth most diagnosed cancer in the world. Infection by the bacteria Helicobacter pylori (HP) is associated with approximately 75% of gastric cancer cases. HP infection induces chronic gastric inflammation, damaging the stomach and fostering carcinogenesis. Most mechanistic studies on gastric cancer initiation are performed in mice and utilize either mouse-adapted strains of HP or the natural mouse pathogen Helicobacter felis (HF). Here, we identified the differences in gastric inflammation, atrophy, and metaplasia associated with HP and HF infection in mice. PMSS1 HP strain or the CS1 HF strain were co-cultured with mouse peritoneal macrophages to assess their immunostimulatory effects. HP and HF induced similar cytokine production from cultured mouse peritoneal macrophages revealing that both bacteria exhibit similar immunostimulatory effects in vitro. Next, C57BL/6J mice were infected with HP or HF and were assessed 2 months post-infection. HP-infected mice caused modest inflammation within both the gastric corpus and antrum, and did not induce significant atrophy within the gastric corpus. In contrast, HF induced significant inflammation throughout the gastric corpus and antrum. Moreover, HF infection was associated with significant atrophy of the chief and parietal cell compartments and induced the expression of pyloric metaplasia (PM) markers. HP is poorly immunogenic compared to HF. HF induces dramatic CD4+ T cell activation, which is associated with increased gastric cancer risk in humans. Thus, HP studies in mice are better suited for studies on colonization, while HF is more strongly suited for studies on the effects of gastric inflammation on tumorigenesis. . IMPORTANCE Mouse infection models with Helicobacter species are widely used to study Helicobacter pathogenesis and gastric cancer initiation. However, Helicobacter pylori is not a natural mouse pathogen, and mouse-adapted H. pylori strains are poorly immunogenic. In contrast, Helicobacter felis is a natural mouse pathogen that induces robust gastric inflammation and is often used in mice to investigate gastric cancer initiation. Although both bacterial strains are widely used, their disease pathogenesis in mice differs dramatically. However, few studies have directly compared the pathogenesis of these bacterial species in mice, and the contrasting features of these two models are not clearly defined. This study directly compares the gastric inflammation, atrophy, and metaplasia development triggered by the widely used PMSS1 H. pylori and CS1 H. felis strains in mice. It serves as a useful resource for researchers to select the experimental model best suited for their studies.
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Affiliation(s)
- Sara R Druffner
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - Shrinidhi Venkateshwaraprabu
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - Stuti Khadka
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - Benjamin C Duncan
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - Maeve T Morris
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - Emel Sen-Kilic
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - Fredrick H Damron
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - George W Liechti
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Jonathan T Busada
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
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2
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Fields JL, Zhang H, Bellis NF, Petersen HA, Halder SK, Rich-New ST, Wu H, Wang F. Structural diversity and clustering of bacterial flagellar outer domains. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.18.585621. [PMID: 38562817 PMCID: PMC10983879 DOI: 10.1101/2024.03.18.585621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Supercoiled flagellar filaments function as mechanical propellers within the bacterial flagellum complex, playing a crucial role in motility. Flagellin, the building block of the filament, features a conserved inner D0/D1 core domain across different bacterial species. In contrast, approximately half of the flagellins possess additional, highly divergent outer domain(s), suggesting varied functional potential. In this study, we elucidate atomic structures of flagellar filaments from three distinct bacterial species: Cupriavidus gilardii , Stenotrophomonas maltophilia , and Geovibrio thiophilus . Our findings reveal that the flagella from the facultative anaerobic G. thiophilus possesses a significantly more negatively charged surface, potentially enabling adhesion to positively charged minerals. Furthermore, we analyzed all AlphaFold predicted structures for annotated bacterial flagellins, categorizing the flagellin outer domains into 682 structural clusters. This classification provides insights into the prevalence and experimental verification of these outer domains. Remarkably, two of the flagellar structures reported herein belong to a previously unexplored cluster, indicating new opportunities on the study of the functional diversity of flagellar outer domains. Our findings underscore the complexity of bacterial flagellins and open up possibilities for future studies into their varied roles beyond motility.
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Fan J, Zhu J, Xu H. Strategies of Helicobacter pylori in evading host innate and adaptive immunity: insights and prospects for therapeutic targeting. Front Cell Infect Microbiol 2024; 14:1342913. [PMID: 38469348 PMCID: PMC10925771 DOI: 10.3389/fcimb.2024.1342913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 02/08/2024] [Indexed: 03/13/2024] Open
Abstract
Helicobacter pylori (H. pylori) is the predominant pathogen causing chronic gastric mucosal infections globally. During the period from 2011 to 2022, the global prevalence of H. pylori infection was estimated at 43.1%, while in China, it was slightly higher at approximately 44.2%. Persistent colonization by H. pylori can lead to gastritis, peptic ulcers, and malignancies such as mucosa-associated lymphoid tissue (MALT) lymphomas and gastric adenocarcinomas. Despite eliciting robust immune responses from the host, H. pylori thrives in the gastric mucosa by modulating host immunity, particularly by altering the functions of innate and adaptive immune cells, and dampening inflammatory responses adverse to its survival, posing challenges to clinical management. The interaction between H. pylori and host immune defenses is intricate, involving evasion of host recognition by modifying surface molecules, manipulating macrophage functionality, and modulating T cell responses to evade immune surveillance. This review analyzes the immunopathogenic and immune evasion mechanisms of H. pylori, underscoring the importance of identifying new therapeutic targets and developing effective treatment strategies, and discusses how the development of vaccines against H. pylori offers new hope for eradicating such infections.
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Affiliation(s)
- Jiawei Fan
- Department of Gastroenterology, The First Hospital of Jilin University, Changchun, China
| | - Jianshu Zhu
- Department of Spine Surgery, The First Hospital of Jilin University, Changchun, China
| | - Hong Xu
- Department of Gastroenterology, The First Hospital of Jilin University, Changchun, China
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Druffner SR, Venkateshwaraprabu S, Khadka S, Duncan BC, Morris MT, Sen-Kilic E, Damron FH, Liechti GW, Busada JT. Comparison of gastric inflammation and metaplasia induced by Helicobacter pylori or Helicobacter felis colonization in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.22.573128. [PMID: 38187587 PMCID: PMC10769338 DOI: 10.1101/2023.12.22.573128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Background Gastric cancer is the fifth most diagnosed cancer in the world. Infection by the bacteria Helicobacter pylori (HP) is associated with approximately 75% of gastric cancer cases. HP infection induces chronic gastric inflammation, damaging the stomach and fostering carcinogenesis. Most mechanistic studies on Helicobacter- induced gastric cancer initiation are performed in mice and utilize either mouse-adapted strains of HP or the natural mouse pathogen Helicobacter felis (HF). Each of these infection models is associated with strengths and weaknesses. Here, we identified the differences in immunogenicity and gastric pathological changes associated with HP and HF infection in mice. Material and Methods PMSS1 HP strain or with the CS1 HF strain were co-cultured with mouse peritoneal macrophages to assess their immunostimulatory effects. C57BL/6J mice were infected with HP or HF, and gastric inflammation, atrophy, and metaplasia development were assessed 2 months post-infection. Results HP and HF induced similar cytokine production from cultured mouse peritoneal macrophages. HP-infected mice caused modest inflammation within both the gastric corpus and antrum and did not induce significant atrophy within the gastric corpus. In contrast, HF induced significant inflammation throughout the gastric corpus and antrum. Moreover, HF infection was associated with significant atrophy of the chief and parietal cell compartments and induced expression of pyloric metaplasia markers. Conclusions HP is poorly immunogenic compared to HF. HF induces dramatic CD4+ T cell activation, which is associated with increased gastric cancer risk in humans. Thus, HP studies in mice are better suited for studies on colonization, while HF is more strongly suited for pathogenesis and cancer initiation studies.
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5
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Mukherjee S, Patra R, Behzadi P, Masotti A, Paolini A, Sarshar M. Toll-like receptor-guided therapeutic intervention of human cancers: molecular and immunological perspectives. Front Immunol 2023; 14:1244345. [PMID: 37822929 PMCID: PMC10562563 DOI: 10.3389/fimmu.2023.1244345] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/07/2023] [Indexed: 10/13/2023] Open
Abstract
Toll-like receptors (TLRs) serve as the body's first line of defense, recognizing both pathogen-expressed molecules and host-derived molecules released from damaged or dying cells. The wide distribution of different cell types, ranging from epithelial to immune cells, highlights the crucial roles of TLRs in linking innate and adaptive immunity. Upon stimulation, TLRs binding mediates the expression of several adapter proteins and downstream kinases, that lead to the induction of several other signaling molecules such as key pro-inflammatory mediators. Indeed, extraordinary progress in immunobiological research has suggested that TLRs could represent promising targets for the therapeutic intervention of inflammation-associated diseases, autoimmune diseases, microbial infections as well as human cancers. So far, for the prevention and possible treatment of inflammatory diseases, various TLR antagonists/inhibitors have shown to be efficacious at several stages from pre-clinical evaluation to clinical trials. Therefore, the fascinating role of TLRs in modulating the human immune responses at innate as well as adaptive levels directed the scientists to opt for these immune sensor proteins as suitable targets for developing chemotherapeutics and immunotherapeutics against cancer. Hitherto, several TLR-targeting small molecules (e.g., Pam3CSK4, Poly (I:C), Poly (A:U)), chemical compounds, phytocompounds (e.g., Curcumin), peptides, and antibodies have been found to confer protection against several types of cancers. However, administration of inappropriate doses of such TLR-modulating therapeutics or a wrong infusion administration is reported to induce detrimental outcomes. This review summarizes the current findings on the molecular and structural biology of TLRs and gives an overview of the potency and promises of TLR-directed therapeutic strategies against cancers by discussing the findings from established and pipeline discoveries.
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Affiliation(s)
- Suprabhat Mukherjee
- Integrative Biochemistry & Immunology Laboratory, Department of Animal Science, Kazi Nazrul University, Asansol, West Bengal, India
| | - Ritwik Patra
- Integrative Biochemistry & Immunology Laboratory, Department of Animal Science, Kazi Nazrul University, Asansol, West Bengal, India
| | - Payam Behzadi
- Department of Microbiology, Shahr-e-Qods Branch, Islamic Azad University, Tehran, Iran
| | - Andrea Masotti
- Research Laboratories, Bambino Gesù Children’s Hospital-IRCCS, Rome, Italy
| | - Alessandro Paolini
- Research Laboratories, Bambino Gesù Children’s Hospital-IRCCS, Rome, Italy
| | - Meysam Sarshar
- Research Laboratories, Bambino Gesù Children’s Hospital-IRCCS, Rome, Italy
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Li Y, Yao H, Liu S, Song D, Wu C, Zhang S, Gao Q, Zhang L. The role of flagellin F in Vibrio Parahaemolyticus-induced intestinal immunity and functional domain identification. Int J Biol Macromol 2023; 244:125404. [PMID: 37327919 DOI: 10.1016/j.ijbiomac.2023.125404] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 06/10/2023] [Accepted: 06/13/2023] [Indexed: 06/18/2023]
Abstract
The marine pathogen Vibrio parahaemolyticus has caused huge economic losses to aquaculture. Flagellin is a key bacterial virulence factor that induces an inflammatory response via activation of Toll-like receptor 5 (TLR5) signaling. Herein, to explore the inflammatory activity of V. parahaemolyticus flagellins (flaA, flaB, flaC, flaD, flaE, and flaF), we investigated their ability to induce apoptosis in a fish cell line. All six flagellins induced severe apoptosis. Moreover, treatment with V. parahaemolyticus flagellins increased TLR5 and myeloid differentiation factor 88 (MyD88) expression and the production of TNF-α and IL-8 significantly. This indicated that flagellins might induce a TLR5-meditated immune response via an MyD88-dependent pathway. FlaF exhibited the strongest immunostimulatory effect; therefore, the interaction between TLR5 and flaF was screened using the yeast two-hybrid system. A significant interaction between the two proteins was observed, indicating that flaF binds directly to TLR5. Finally, the amino acids that participate in the TLR5-flaF interaction were identified using molecular simulation, which indicated three binding sites. These results deepen our understanding of the immunogenic properties of flagellins from V. parahaemolyticus, which could be used for vaccine development in the future.
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Affiliation(s)
- Yang Li
- College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Hongqing Yao
- Songjiang Hospital Affiliated to Shanghai Jiaotong University, School of Medicine, Shanghai 201699, PR China
| | - Sushuang Liu
- Department of Life Sciences and Health, School of Science and Engineering, Huzhou College, PR China
| | - Dawei Song
- College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Choufei Wu
- College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Shaoyong Zhang
- College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Quanxin Gao
- College of Life Science, Huzhou University, Huzhou 313000, PR China.
| | - Liqin Zhang
- College of Life Science, Huzhou University, Huzhou 313000, PR China.
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Villarroel-Espindola F, Ejsmentewicz T, Gonzalez-Stegmaier R, Jorquera RA, Salinas E. Intersections between innate immune response and gastric cancer development. World J Gastroenterol 2023; 29:2222-2240. [PMID: 37124883 PMCID: PMC10134417 DOI: 10.3748/wjg.v29.i15.2222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/07/2022] [Accepted: 03/13/2023] [Indexed: 04/14/2023] Open
Abstract
Worldwide, gastric cancer (GC) is the fifth most commonly diagnosed malignancy. It has a reduced prevalence but has maintained its poor prognosis being the fourth leading cause of deaths related to cancer. The highest mortality rates occur in Asian and Latin American countries, where cases are usually diagnosed at advanced stages. Overall, GC is viewed as the consequence of a multifactorial process, involving the virulence of the Helicobacter pylori (H. pylori) strains, as well as some environmental factors, dietary habits, and host intrinsic factors. The tumor microenvironment in GC appears to be chronically inflamed which promotes tumor progression and reduces the therapeutic opportunities. It has been suggested that inflammation assessment needs to be measured qualitatively and quantitatively, considering cell-infiltration types, availability of receptors to detect damage and pathogens, and presence or absence of aggressive H. pylori strains. Gastrointestinal epithelial cells express several Toll-like receptors and determine the first defensive line against pathogens, and have been also described as mediators of tumorigenesis. However, other molecules, such as cytokines related to inflammation and innate immunity, including immune checkpoint molecules, interferon-gamma pathway and NETosis have been associated with an increased risk of GC. Therefore, this review will explore innate immune activation in the context of premalignant lesions of the gastric epithelium and established gastric tumors.
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Affiliation(s)
- Franz Villarroel-Espindola
- Translational Medicine Unit, Instituto Oncologico Fundacion Arturo Lopez Perez, Santiago 7500000, Metropolitan region, Chile
| | - Troy Ejsmentewicz
- Translational Medicine Unit, Instituto Oncologico Fundacion Arturo Lopez Perez, Santiago 7500000, Metropolitan region, Chile
| | - Roxana Gonzalez-Stegmaier
- Translational Medicine Unit, Instituto Oncologico Fundacion Arturo Lopez Perez, Santiago 7500000, Metropolitan region, Chile
| | - Roddy A Jorquera
- Translational Medicine Unit, Instituto Oncologico Fundacion Arturo Lopez Perez, Santiago 7500000, Metropolitan region, Chile
| | - Esteban Salinas
- Translational Medicine Unit, Instituto Oncologico Fundacion Arturo Lopez Perez, Santiago 7500000, Metropolitan region, Chile
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Tas SK, Kirkik D, Altunkanat D, Uzunoglu AS, Uzunoglu MS, Celik BA, Ilgar E. Immune Response and Therapeutic Vaccination against Helicobacter pylori. BRAZILIAN ARCHIVES OF BIOLOGY AND TECHNOLOGY 2023; 66. [DOI: 10.1590/1678-4324-2023230123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
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9
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Yang J, Liu X, Cheng Y, Zhang J, Ji F, Ling Z. Roles of Plasmacytoid Dendritic Cells in Gastric Cancer. Front Oncol 2022; 12:818314. [PMID: 35311157 PMCID: PMC8927765 DOI: 10.3389/fonc.2022.818314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/15/2022] [Indexed: 12/24/2022] Open
Abstract
Gastric cancer (GC) is the fifth most common neoplasm and the third most deadly cancer in humans worldwide. Helicobacter pylori infection is the most important causative factor of gastric carcinogenesis, and activates host innate and adaptive immune responses. As key constituents of the tumor immune microenvironment, plasmacytoid dendritic cells (pDCs) are increasingly attracting attention owing to their potential roles in immunosuppression. We recently reported that pDCs have vital roles in the development of immunosuppression in GC. Clarifying the contribution of pDCs to the development and progression of GC may lead to improvements in cancer therapy. In this review, we summarize current knowledge regarding immune modulation in GC, especially the roles of pDCs in GC carcinogenesis and treatment strategies.
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Affiliation(s)
- Jinpu Yang
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xia Liu
- Department of Intensive Care Unit, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yiwen Cheng
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jingchen Zhang
- Department of Intensive Care Unit, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Feng Ji
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zongxin Ling
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.,Jinan Microecological Biomedicine Shandong Laboratory, Jinan, China
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10
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Jin S, Nepal N, Gao Y. The role of toll-like receptors in peptic ulcer disease. Immunol Med 2021; 45:69-78. [PMID: 34657578 DOI: 10.1080/25785826.2021.1963190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Helicobacter pylori (HP) is the primary etiologic factor that induces events in the immune system that lead to peptic ulcers. Toll-like receptors (TLRs) are an important part of the innate immune system, as they play pivotal roles in pathogen-associated molecular pattern (PAMP) recognition of HP as well host-associated damage-associated molecular patterns (DAMPs). Recent advancements such as COX-2 production, LPS recognition through TLR2, CagL, and CagY protein of HP activating TLR5, TLR9 activation via type IV secretion system (T4SS) using DNA transfer, TLR polymorphisms, their adaptor molecules, cytokines, and other factors play a significant role in PUD. Thus, some novel PUD treatments including Chuyou Yuyang granules, function by TLR4/NF-κB signaling pathway suppression and TNF-α and IL-18 inhibition also rely on TLR signaling. Similarly glycyrrhetinic acid (GA) treatment activates TLR-4 in Ana-1 cells not via TRIF, but via MYD88 expression, which is significantly upregulated to cure PUD. Therefore, understanding TLR signaling complexity and its resultant immune modulation after host-pathogen interactions is pivotal to drug and vaccine development for other diseases as well including cancer and recent pandemic COVID-19. In this review, we summarize the TLRs and HP interaction; its pathophysiology-related signaling pathways, polymorphisms, and pharmaceutical approaches toward PUD.
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Affiliation(s)
- Shizhu Jin
- Department of Gastroenterology and Hepatology, The Second Affiliated Hospital, Harbin Medical University, Harbin, P. R. China
| | - Narayan Nepal
- Department of Gastroenterology and Hepatology, The Second Affiliated Hospital, Harbin Medical University, Harbin, P. R. China
| | - Yang Gao
- Department of Gastroenterology and Hepatology, The Second Affiliated Hospital, Harbin Medical University, Harbin, P. R. China
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Holzapfel M, Bonhomme D, Cagliero J, Vernel-Pauillac F, Fanton d'Andon M, Bortolussi S, Fiette L, Goarant C, Wunder EA, Picardeau M, Ko AI, Werling D, Matsui M, Boneca IG, Werts C. Escape of TLR5 Recognition by Leptospira spp.: A Rationale for Atypical Endoflagella. Front Immunol 2020; 11:2007. [PMID: 32849665 PMCID: PMC7431986 DOI: 10.3389/fimmu.2020.02007] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/24/2020] [Indexed: 12/26/2022] Open
Abstract
Leptospira (L.) interrogans are invasive bacteria responsible for leptospirosis, a worldwide zoonosis. They possess two periplasmic endoflagellae that allow their motility. L. interrogans are stealth pathogens that escape the innate immune recognition of the NOD-like receptors NOD1/2, and the human Toll-like receptor (TLR)4, which senses peptidoglycan and lipopolysaccharide (LPS), respectively. TLR5 is another receptor of bacterial cell wall components, recognizing flagellin subunits. To study the contribution of TLR5 in the host defense against leptospires, we infected WT and TLR5 deficient mice with pathogenic L. interrogans and tracked the infection by in vivo live imaging of bioluminescent bacteria or by qPCR. We did not identify any protective or inflammatory role of murine TLR5 for controlling pathogenic Leptospira. Likewise, subsequent in vitro experiments showed that infections with different live strains of L. interrogans and L. biflexa did not trigger TLR5 signaling. However, unexpectedly, heat-killed bacteria stimulated human and bovine TLR5, but did not, or barely induced stimulation via murine TLR5. Abolition of TLR5 recognition required extensive boiling time of the bacteria or proteinase K treatment, showing an unusual high stability of the leptospiral flagellins. Interestingly, after using antimicrobial peptides to destabilize live leptospires, we detected TLR5 activity, suggesting that TLR5 could participate in the fight against leptospires in humans or cattle. Using different Leptospira strains with mutations in the flagellin proteins, we further showed that neither FlaA nor Fcp participated in the recognition by TLR5, suggesting a role for the FlaB. FlaB have structural homology to Salmonella FliC, and possess conserved residues important for TLR5 activation, as shown by in silico analyses. Accordingly, we found that leptospires regulate the expression of FlaB mRNA according to the growth phase in vitro, and that infection with L. interrogans in hamsters and in mice downregulated the expression of the FlaB, but not the FlaA subunits. Altogether, in contrast to different bacteria that modify their flagellin sequences to escape TLR5 recognition, our study suggests that the peculiar central localization and stability of the FlaB monomers in the periplasmic endoflagellae, associated with the downregulation of FlaB subunits in hosts, constitute an efficient strategy of leptospires to escape the TLR5 recognition and the induced immune response.
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Affiliation(s)
- Marion Holzapfel
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Delphine Bonhomme
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France.,Sorbonne Paris Cité, Université de Paris, Paris, France
| | - Julie Cagliero
- Institut Pasteur de Nouvelle Calédonie, Immunity and Inflammation Group, Institut Pasteur International Network, Noumea, France
| | - Frédérique Vernel-Pauillac
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Martine Fanton d'Andon
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Sophia Bortolussi
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Laurence Fiette
- Unité Histopathologie Humaine et Modèles Animaux, Institut Pasteur, Paris, France
| | - Cyrille Goarant
- Leptospirosis Research and Expertise Unit, Institut Pasteur International Network, Institut Pasteur de Nouvelle Calédonie, Noumea, France
| | - Elsio A Wunder
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Brazil.,Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
| | | | - Albert I Ko
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Brazil.,Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
| | - Dirk Werling
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | - Mariko Matsui
- Institut Pasteur de Nouvelle Calédonie, Immunity and Inflammation Group, Institut Pasteur International Network, Noumea, France
| | - Ivo G Boneca
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Catherine Werts
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
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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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