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Liu X, Lertsethtakarn P, Mariscal VT, Yildiz F, Ottemann KM. Counterclockwise rotation of the flagellum promotes biofilm initiation in Helicobacter pylori. mBio 2024; 15:e0044024. [PMID: 38700325 PMCID: PMC11237671 DOI: 10.1128/mbio.00440-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 03/26/2024] [Indexed: 05/05/2024] Open
Abstract
Motility promotes biofilm initiation during the early steps of this process: microbial surface association and attachment. Motility is controlled in part by chemotaxis signaling, so it seems reasonable that chemotaxis may also affect biofilm formation. There is a gap, however, in our understanding of the interactions between chemotaxis and biofilm formation, partly because most studies analyzed the phenotype of only a single chemotaxis signaling mutant, e.g., cheA. Here, we addressed the role of chemotaxis in biofilm formation using a full set of chemotaxis signaling mutants in Helicobacter pylori, a class I carcinogen that infects more than half the world's population and forms biofilms. Using mutants that lack each chemotaxis signaling protein, we found that chemotaxis signaling affected the biofilm initiation stage, but not mature biofilm formation. Surprisingly, some chemotaxis mutants elevated biofilm initiation, while others inhibited it in a manner that was not tied to chemotaxis ability or ligand input. Instead, the biofilm phenotype correlated with flagellar rotational bias. Specifically, mutants with a counterclockwise bias promoted biofilm initiation, e.g., ∆cheA, ∆cheW, or ∆cheV1; in contrast, those with a clockwise bias inhibited it, e.g., ∆cheZ, ∆chePep, or ∆cheV3. We tested this correlation using a counterclockwise bias-locked flagellum, which induced biofilm formation independent of the chemotaxis system. These CCW flagella, however, were not sufficient to induce biofilm formation, suggesting there are downstream players. Overall, our work highlights the new finding that flagellar rotational direction promotes biofilm initiation, with the chemotaxis signaling system operating as one mechanism to control flagellar rotation. IMPORTANCE Chemotaxis signaling systems have been reported to contribute to biofilm formation in many bacteria; however, how they regulate biofilm formation remains largely unknown. Chemotaxis systems are composed of many distinct kinds of proteins, but most previous work analyzed the biofilm effect of loss of only a few. Here, we explored chemotaxis' role during biofilm formation in the human-associated pathogenic bacterium Helicobacter pylori. We found that chemotaxis proteins are involved in biofilm initiation in a manner that correlated with how they affected flagellar rotation. Biofilm initiation was high in mutants with counterclockwise (CCW) flagellar bias and low in those with clockwise bias. We supported the idea that a major driver of biofilm formation is flagellar rotational direction using a CCW-locked flagellar mutant, which stays CCW independent of chemotaxis input and showed elevated biofilm initiation. Our data suggest that CCW-rotating flagella, independent of chemotaxis inputs, are a biofilm-promoting signal.
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Affiliation(s)
- Xiaolin Liu
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California, USA
| | - Paphavee Lertsethtakarn
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California, USA
| | - Vanessa T. Mariscal
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California, USA
| | - Fitnat Yildiz
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California, USA
| | - Karen M. Ottemann
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California, USA
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2
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Tammara V, Angrover R, Sirur D, Das A. Flagellar motor protein-targeted search for the druggable site of Helicobacter pylori. Phys Chem Chem Phys 2024; 26:2111-2126. [PMID: 38131449 DOI: 10.1039/d3cp05024f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The deleterious impact of Helicobacter pylori (H. pylori) on human health is contingent upon its ability to create and sustain colony structure, which in turn is dictated by the effective performance of flagella - a multi-protein rotary nanodevice. Hence, to design an effective therapeutic strategy against H. pylori, we here conducted a systematic search for an effective druggable site by focusing on the structure-dynamics-energetics-stability landscape of the junction points of three 1 : 1 protein complexes (FliFC-FliGN, FliGM-FliMM, and FliYC-FliNC) that contribute mainly to the rotary motion of the flagella via the transformation of information along the junctions over a wide range of pH values operative in the stomach (from neutral to acidic). We applied a gamut of physiologically relevant perturbations in the form of thermal scanning and mechanical force to sample the entire quasi - and non-equilibrium conformational spaces available for the protein complexes under neutral and acidic pH conditions. Our perturbation-induced magnification of conformational distortion approach identified pH-independent protein sequence-specific evolution of precise thermally labile segments, which dictate the specific thermal unfolding mechanism of each complex and this complex-specific pH-independent structural disruption notion remains consistent under mechanical stress as well. Complementing the above observations with the relative rank-ordering of estimated equilibrium binding free energies between two protein sequences of a specific complex quantifies the extent of structure-stability modulation due to pH alteration, rationalizes the exceptional stability of H. pylori under acidic pH conditions, and identifies the pH-independent complex-sequence-segment-residue diagram for targeted drug design.
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Affiliation(s)
- Vaishnavi Tammara
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune, Maharashtra 411008, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Ruchika Angrover
- The Departments of the University Institute of Biotechnology, Chandigarh University, NH-05, Ludhiana - Chandigarh State Highway, Punjab 140413, India
| | - Disha Sirur
- School of Physical Sciences, National Institute of Science Education & Research-Bhubaneswar, An OCC of Homi Bhabha National Institute, P.O. Jatni, Khurda, Odisha 752050, India
| | - Atanu Das
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune, Maharashtra 411008, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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3
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Ribardo DA, Johnson JJ, Hendrixson DR. Viscosity-dependent determinants of Campylobacter jejuni impacting the velocity of flagellar motility. mBio 2024; 15:e0254423. [PMID: 38085029 PMCID: PMC10790790 DOI: 10.1128/mbio.02544-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 11/06/2023] [Indexed: 01/17/2024] Open
Abstract
IMPORTANCE Bacteria can adapt flagellar motor output in response to the load that the extracellular milieu imparts on the flagellar filament to enable propulsion. Bacteria can adapt flagellar motor output in response to the load that the extracellular milieu imparts on the flagellar filament to enable propulsion through diverse environments. These changes may involve increasing power and torque in high-viscosity environments or reducing power and flagellar rotation upon contact with a surface. C. jejuni swimming velocity in low-viscosity environments is comparable to other bacterial flagellates and increases significantly as external viscosity increases. In this work, we provide evidence that the mechanics of the C. jejuni flagellar motor has evolved to naturally promote high swimming velocity in high-viscosity environments. We found that C. jejuni produces VidA and VidB as auxiliary proteins to specifically affect flagellar motor activity in low viscosity to reduce swimming velocity. Our findings provide some of the first insights into different mechanisms that exist in bacteria to alter the mechanics of a flagellar motor, depending on the viscosity of extracellular environments.
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Affiliation(s)
- Deborah A. Ribardo
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jeremiah J. Johnson
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - David R. Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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4
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Nguyen TKC, Do HDK, Nguyen TLP, Pham TT, Mach BN, Nguyen TC, Pham TL, Katsande PM, Hong HA, Duong HT, Phan AN, Cutting SM, Vu MT, Nguyen VD. Genomic and vaccine preclinical studies reveal a novel mouse-adapted Helicobacter pylori model for the hpEastAsia genotype in Southeast Asia. J Med Microbiol 2024; 73. [PMID: 38235783 DOI: 10.1099/jmm.0.001786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024] Open
Abstract
Introduction. Helicobacter pylori infection is a major global health concern, linked to the development of various gastrointestinal diseases, including gastric cancer. To study the pathogenesis of H. pylori and develop effective intervention strategies, appropriate animal pathogen models that closely mimic human infection are essential.Gap statement. This study focuses on the understudied hpEastAsia genotype in Southeast Asia, a region marked by a high H. pylori infection rate. No mouse-adapted model strains has been reported previously. Moreover, it recognizes the urgent requirement for vaccines in developing countries, where overuse of antimicrobials is fuelling the emergence of resistance.Aim. This study aims to establish a novel mouse-adapted H. pylori model specific to the hpEastAsia genotype prevalent in Southeast Asia, focusing on comparative genomic and histopathological analysis of pathogens coupled with vaccine preclinical studies.Methodology. We collected and sequenced the whole genome of clinical strains of H. pylori from infected patients in Vietnam and performed comparative genomic analyses of H. pylori strains in Southeast Asia. In parallel, we conducted preclinical studies to assess the pathogenicity of the mouse-adapted H. pylori strain and the protective effect of a new spore-vectored vaccine candidate on male Mlac:ICR mice and the host immune response in a female C57BL/6 mouse model.Results. Genome sequencing and comparison revealed unique and common genetic signatures, antimicrobial resistance genes and virulence factors in strains HP22 and HP34; and supported clarithromycin-resistant HP34 as a representation of the hpEastAsia genotype in Vietnam and Southeast Asia. HP34-infected mice exhibited gastric inflammation, epithelial erosion and dysplastic changes that closely resembled the pathology observed in human H. pylori infection. Furthermore, comprehensive immunological characterization demonstrated a robust host immune response, including both mucosal and systemic immune responses. Oral vaccination with candidate vaccine formulations elicited a significant reduction in bacterial colonization in the model.Conclusion. Our findings demonstrate the successful development of a novel mouse-adapted H. pylori model for the hpEastAsia genotype in Vietnam and Southeast Asia. Our research highlights the distinctive genotype and pathogenicity of clinical H. pylori strains in the region, laying the foundation for targeted interventions to address this global health burden.
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Affiliation(s)
- Thi Kim Cuc Nguyen
- Institute of Biotechnology and Environment, Nha Trang University, 2 Nguyen Dinh Chieu Street, Khanh Hoa, Vietnam
| | - Hoang Dang Khoa Do
- NTT Hi-tech Institute, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh, Ho Chi Minh City, Vietnam
| | - Thi Lan Phuong Nguyen
- Institute of Vaccines and Biological Medicals (IVAC), 9 Pasteur Street, Nha Trang, Khanh Hoa, Vietnam
| | - Thu Thuy Pham
- Institute of Biotechnology and Environment, Nha Trang University, 2 Nguyen Dinh Chieu Street, Khanh Hoa, Vietnam
| | - Bao Ngoc Mach
- NTT Hi-tech Institute, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh, Ho Chi Minh City, Vietnam
| | - Thi Chinh Nguyen
- Institute of Biotechnology and Environment, Nha Trang University, 2 Nguyen Dinh Chieu Street, Khanh Hoa, Vietnam
| | - Thi Lan Pham
- Institute of Biotechnology and Environment, Nha Trang University, 2 Nguyen Dinh Chieu Street, Khanh Hoa, Vietnam
| | - Paidamoyo M Katsande
- Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Huynh Anh Hong
- Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Huu Thai Duong
- Institute of Vaccines and Biological Medicals (IVAC), 9 Pasteur Street, Nha Trang, Khanh Hoa, Vietnam
| | - Anh N Phan
- School of Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Simon M Cutting
- Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Minh Thiet Vu
- NTT Hi-tech Institute, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh, Ho Chi Minh City, Vietnam
| | - Van Duy Nguyen
- Institute of Biotechnology and Environment, Nha Trang University, 2 Nguyen Dinh Chieu Street, Khanh Hoa, Vietnam
- School of Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
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5
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Botting JM, Tachiyama S, Gibson KH, Liu J, Starai VJ, Hoover TR. FlgV forms a flagellar motor ring that is required for optimal motility of Helicobacter pylori. PLoS One 2023; 18:e0287514. [PMID: 37976320 PMCID: PMC10655999 DOI: 10.1371/journal.pone.0287514] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 06/07/2023] [Indexed: 11/19/2023] Open
Abstract
Flagella-driven motility is essential for Helicobacter pylori to colonize the human stomach, where it causes a variety of diseases, including chronic gastritis, peptic ulcer disease, and gastric cancer. H. pylori has evolved a high-torque-generating flagellar motor that possesses several accessories not found in the archetypical Escherichia coli motor. FlgV was one of the first flagellar accessory proteins identified in Campylobacter jejuni, but its structure and function remain poorly understood. Here, we confirm that deletion of flgV in H. pylori B128 and a highly motile variant of H. pylori G27 (G27M) results in reduced motility in soft agar medium. Comparative analyses of in-situ flagellar motor structures of wild-type, ΔflgV, and a strain expressing FlgV-YFP showed that FlgV forms a ring-like structure closely associated with the junction of two highly conserved flagellar components: the MS and C rings. The results of our studies suggest that the FlgV ring has adapted specifically in Campylobacterota to support the assembly and efficient function of the high-torque-generating motors.
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Affiliation(s)
- Jack M. Botting
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
| | - Shoichi Tachiyama
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, United States of America
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Katherine H. Gibson
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
| | - Jun Liu
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, United States of America
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Vincent J. Starai
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
| | - Timothy R. Hoover
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
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6
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Gupta N, Kumar A, Verma VK. Strategies adopted by gastric pathogen Helicobacter pylori for a mature biofilm formation: Antimicrobial peptides as a visionary treatment. Microbiol Res 2023; 273:127417. [PMID: 37267815 DOI: 10.1016/j.micres.2023.127417] [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: 03/13/2023] [Revised: 05/15/2023] [Accepted: 05/21/2023] [Indexed: 06/04/2023]
Abstract
Enormous efforts in recent past two decades to eradicate the pathogen that has been prevalent in half of the world's population have been problematic. The biofilm formed by Helicobacter pylori provides resistance towards innate immune cells, various combinatorial antibiotics, and human antimicrobial peptides, despite the fact that these all are potent enough to eradicate it in vitro. Biofilm provides the opportunity to secrete various virulence factors that strengthen the interaction between host and pathogen helping in evading the innate immune system and ultimately leading to persistence. To our knowledge, this review is the first of its kind to explain briefly the journey of H. pylori starting with the chemotaxis, the mechanism for selecting the site for colonization, the stress faced by the pathogen, and various adaptations to evade these stress conditions by forming biofilm and the morphological changes acquired by the pathogen in mature biofilm. Furthermore, we have explained the human GI tract antimicrobial peptides and the reason behind the failure of these AMPs, and how encapsulation of Pexiganan-A(MSI-78A) in a chitosan microsphere increases the efficiency of eradication.
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Affiliation(s)
- Nidhi Gupta
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Marg, New Delhi 110021, India.
| | - Atul Kumar
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Marg, New Delhi 110021, India
| | - Vijay Kumar Verma
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Marg, New Delhi 110021, India.
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7
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Diving into the complexity of the spirochetal endoflagellum. Trends Microbiol 2023; 31:294-307. [PMID: 36244923 DOI: 10.1016/j.tim.2022.09.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/12/2022] [Accepted: 09/14/2022] [Indexed: 11/27/2022]
Abstract
Spirochaetes, a phylum that includes medically important pathogens such as the causative agents of Lyme disease, syphilis, and leptospirosis, are in many ways highly unique bacteria. Their cell morphology, subcellular organization, and metabolism reveal atypical features. Spirochetal motility is also singular, dependent on the presence of periplasmic flagella or endoflagella, inserted subterminally at cell poles and not penetrating the outer membrane and elongating outside the cell as in enterobacteria. In this review we present a comprehensive comparative genomics analysis of endoflagellar systems in spirochetes, highlighting recent findings on the flagellar basal body and filament. Continued progress in understanding the function and architecture of spirochetal flagella is uncovering paradigm-shifting mechanisms of bacterial motility.
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8
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Cutler KJ, Stringer C, Lo TW, Rappez L, Stroustrup N, Brook Peterson S, Wiggins PA, Mougous JD. Omnipose: a high-precision morphology-independent solution for bacterial cell segmentation. Nat Methods 2022; 19:1438-1448. [PMID: 36253643 PMCID: PMC9636021 DOI: 10.1038/s41592-022-01639-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 09/06/2022] [Indexed: 12/26/2022]
Abstract
Advances in microscopy hold great promise for allowing quantitative and precise measurement of morphological and molecular phenomena at the single-cell level in bacteria; however, the potential of this approach is ultimately limited by the availability of methods to faithfully segment cells independent of their morphological or optical characteristics. Here, we present Omnipose, a deep neural network image-segmentation algorithm. Unique network outputs such as the gradient of the distance field allow Omnipose to accurately segment cells on which current algorithms, including its predecessor, Cellpose, produce errors. We show that Omnipose achieves unprecedented segmentation performance on mixed bacterial cultures, antibiotic-treated cells and cells of elongated or branched morphology. Furthermore, the benefits of Omnipose extend to non-bacterial subjects, varied imaging modalities and three-dimensional objects. Finally, we demonstrate the utility of Omnipose in the characterization of extreme morphological phenotypes that arise during interbacterial antagonism. Our results distinguish Omnipose as a powerful tool for characterizing diverse and arbitrarily shaped cell types from imaging data.
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Affiliation(s)
- Kevin J Cutler
- Department of Physics, University of Washington, Seattle, WA, USA
| | | | - Teresa W Lo
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Luca Rappez
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Nicholas Stroustrup
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - S Brook Peterson
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Paul A Wiggins
- Department of Physics, University of Washington, Seattle, WA, USA.
- Department of Bioengineering, University of Washington, Seattle, WA, USA.
| | - Joseph D Mougous
- Department of Microbiology, University of Washington, Seattle, WA, USA.
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA.
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9
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Abstract
Helicobacter pylori plays a causative role in gastric diseases. The pathogenicity of H. pylori depends on its ability to colonize the stomach guided by motility. FliY is a unique flagellar motor switch component coexisting with the classical FliG, FliM, and FliN switch proteins in some bacteria and has been shown to be essential for flagellation. However, the functional importance of FliY in H. pylori flagellar motor assembly is not well understood. Here, we applied cryo-electron tomography and subtomogram averaging to analyze the in situ structures of flagellar motors from wild-type strain, fliY-null mutant and complementation mutants expressing the N-terminal or C-terminal domain of FliY. Loss of full-length FliY or its C-terminal domain interrupted the formation of an intact C ring and soluble export apparatus, as well as the hook and flagellar filaments. Complementation with FliY C-terminal domain restored all these missing components of flagellar motor. Taken together, these results provide structural insights into the roles of FliY, especially its C-terminal domain in flagellar motor assembly in H. pylori. IMPORTANCEHelicobacter pylori is the major risk factor related with gastric diseases. Flagellar motor is one of the most important virulence factors in H. pylori. However, the assembly mechanism of H. pylori flagellar motor is not fully understood yet. Previous report mainly described the overall structures of flagellum but had not focused on its specific components. Here, we focus on H. pylori flagellar C-ring protein FliY. We directly visualize the flagellar structures of H. pylori wild-type and FliY N-/C-terminal complementary strains by cryo-electron tomography and subtomogram averaging. Our results show that deletion of FliY or its C-terminal domain causes the loss of C ring, whereas deletion of FliY N-terminal does not affect C-ring assembly and flagellar structures. Our results provide direct evidence that C-ring protein FliY, especially its C-terminal domain, plays an indispensable role in H. pylori motor assembly and flagellar formation. This study will deepen our understanding about H. pylori pathogenesis.
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10
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Xie W, Zhao W, Zou Z, Kong L, Yang L. Oral multivalent epitope vaccine, based on UreB, HpaA, CAT, and LTB, for prevention and treatment of Helicobacter pylori infection in C57BL / 6 mice. Helicobacter 2021; 26:e12807. [PMID: 33847026 DOI: 10.1111/hel.12807] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 03/19/2021] [Accepted: 03/26/2021] [Indexed: 01/03/2023]
Abstract
BACKGROUND As the resistance of Helicobacter pylori to traditional triple therapy is gradually revealed, an increasing number of people are focusing on vaccine treatments for H. pylori infection. Epitope vaccines are a promising strategy for the treatment of H. pylori infection, and multivalent vaccines will be more effective than monovalent vaccines. MATERIALS AND METHODS In this study, we designed a multivalent vaccine named LHUC, which consists of the adjuvant LTB as well as three Th cell epitopes (HpaA154-171 , UreB237-251, and UreB546-561 ) and five B-cell epitopes (UreB349-363 , UreB327-334 , CAT394-405 , CAT387-397, and HpaA132-141 ) from UreB, HpaA, and catalase. In BALB/c mice, the specificity and immunogenicity of the fusion peptide LHUC and the neutralization of H. pylori urease and catalase by the specific IgG elicited by LHUC were evaluated. The preventive and therapeutic effects of LHUC were evaluated in C57BL/6 mice infected with H. pylori. RESULTS The results showed that compared with LTB and PBS, LHUC induced specific IgG and IgA antibody production in mice, and IgG antibodies significantly inhibited the H. pylori urease and catalase activities in vitro. Additionally, by detecting the levels of IFN-γ, IL-4, and IL-17 in lymphocyte supernatants, we proved that LHUC could activate Th1, Th2, and Th17 mixed T-cell immune responses in vivo. Finally, a C57BL/6 mouse model of gastric infection with H. pylori was established. The results showed that compared with the effects of LTB and PBS, the prevention and treatment effects of oral inoculation with LHUC significantly inhibited bacterial colonization. CONCLUSIONS In conclusion, LHUC, a multivalent vaccine based on multiple H. pylori antigens, is a promising and safe vaccine that can effectively reduce the colonization of H. pylori in the stomach.
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Affiliation(s)
- Wenwei Xie
- Department of Natural Medicinal Chemistry, China Pharmaceutical University, Nanjing, China
| | - Wenfeng Zhao
- Department of Biochemistry, China Pharmaceutical university, Nanjing, China
| | - Ziling Zou
- Department of Natural Medicinal Chemistry, China Pharmaceutical University, Nanjing, China
| | - Lingyi Kong
- Department of Natural Medicinal Chemistry, China Pharmaceutical University, Nanjing, China
| | - Lei Yang
- Department of Natural Medicinal Chemistry, China Pharmaceutical University, Nanjing, China
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11
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Reshetnyak VI, Burmistrov AI, Maev IV. Helicobacter pylori: Commensal, symbiont or pathogen? World J Gastroenterol 2021; 27:545-560. [PMID: 33642828 PMCID: PMC7901052 DOI: 10.3748/wjg.v27.i7.545] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 12/28/2020] [Accepted: 01/21/2021] [Indexed: 02/06/2023] Open
Abstract
This review considers the data on Helicobacter pylori (H. pylori), which have been accumulated over 40 years since its description as an etiological factor in gastrointestinal diseases. The majority of modern publications are devoted to the study of the pathogenic properties of the microorganism in the development of chronic gastritis, peptic ulcer disease, and gastric cancer, as well as methods for its eradication. However, in recent years, there have been more and more studies which have suggested that H. pylori has a beneficial, or potentially positive, effect on the human body. The authors have attempted to objectively analyze the information accumulated in the literature on H. pylori. Some studies consider it as one of the recently identified human bacterial pathogens, and special attention is paid to the evidence suggesting that it is probably part of the composition of the human microbiome as a commensal (commensal from French to English is a table companion) or even a symbiont. The presented data discussing the presence or absence of the effect of H. pylori on human health suggest that there is an apparent ambiguity of the problem. The re-assessment of the data available on H. pylori infection is important in order to answer the question of whether it is necessary to create a program of mass H. pylori eradication or to apply a more personalized approach to treating patients with H. pylori-associated gastrointestinal diseases and to perform eradication therapy.
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Affiliation(s)
- Vasiliy Ivanovich Reshetnyak
- Department of Propaedeutic of Internal Diseases and Gastroenterology, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow 127473, Russia
| | - Alexandr Igorevich Burmistrov
- Department of Propaedeutic of Internal Diseases and Gastroenterology, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow 127473, Russia
| | - Igor Veniaminovich Maev
- Department of Propaedeutic of Internal Diseases and Gastroenterology, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow 127473, Russia
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12
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Antani JD, Sumali AX, Lele TP, Lele PP. Asymmetric random walks reveal that the chemotaxis network modulates flagellar rotational bias in Helicobacter pylori. eLife 2021; 10:63936. [PMID: 33493107 PMCID: PMC7834020 DOI: 10.7554/elife.63936] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 01/12/2021] [Indexed: 12/14/2022] Open
Abstract
The canonical chemotaxis network modulates the bias for a particular direction of rotation in the bacterial flagellar motor to help the cell migrate toward favorable chemical environments. How the chemotaxis network in Helicobacter pylori modulates flagellar functions is unknown, which limits our understanding of chemotaxis in this species. Here, we determined that H. pylori swim faster (slower) whenever their flagella rotate counterclockwise (clockwise) by analyzing their hydrodynamic interactions with bounding surfaces. This asymmetry in swimming helped quantify the rotational bias. Upon exposure to a chemo-attractant, the bias decreased and the cells tended to swim exclusively in the faster mode. In the absence of a key chemotaxis protein, CheY, the bias was zero. The relationship between the reversal frequency and the rotational bias was unimodal. Thus, H. pylori’s chemotaxis network appears to modulate the probability of clockwise rotation in otherwise counterclockwise-rotating flagella, similar to the canonical network.
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Affiliation(s)
- Jyot D Antani
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, United States
| | - Anita X Sumali
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, United States
| | - Tanmay P Lele
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77840, College Station, TX 77840, United States.,Department of Translational Medical Sciences, Texas A&M University, Houston, TX 77030, United States
| | - Pushkar P Lele
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, United States
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13
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Dey TK, Karmakar BC, Sarkar A, Paul S, Mukhopadhyay AK. A Mouse Model of Helicobacter pylori Infection. Methods Mol Biol 2021; 2283:131-151. [PMID: 33765316 DOI: 10.1007/978-1-0716-1302-3_14] [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] [Indexed: 12/12/2022]
Abstract
Infection with Helicobacter pylori (H. pylori) is of great distress because of its vital role in the pathogenesis of chronic gastritis, peptic ulcers, and in the multi-step carcinogenic process of gastric cancer. The increasing antibiotic resistance pattern of H. pylori worldwide has prompted the World Health Organization to put this organism in the priority pathogens list. To study the disease biology, evaluation of drugs, treatment outcome and to come up with probable vaccination strategies, competent animal models that reproduce the signature of human infection are essential. Initial reports about animal colonization with H. pylori have shown significant heterogeneity, to such an extent that Barry Marshall, Nobel laureate for the discovery of H. pylori , infected himself with the bacterium to show its involvement in acute gastric illness. A paradigm-shift discovery of the H. pylori mouse-adapted strain SS1 has opened the avenues of research regarding the organism and its pathogenicity. Although the mouse model of H. pylori infection is being utilized all over the world, there are certain issues that need awareness and specific information to achieve successful, consistent colonization with symptoms resembling human. This chapter details an established and reliable protocol for the development of a competent mouse model for H. pylori infection leading to various gastro-intestinal diseases.
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Affiliation(s)
- Tanmoy Kumar Dey
- Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Bipul Chandra Karmakar
- Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Avijit Sarkar
- Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Sangita Paul
- Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Asish Kumar Mukhopadhyay
- Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India.
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14
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Baj J, Forma A, Sitarz M, Portincasa P, Garruti G, Krasowska D, Maciejewski R. Helicobacter pylori Virulence Factors-Mechanisms of Bacterial Pathogenicity in the Gastric Microenvironment. Cells 2020; 10:E27. [PMID: 33375694 PMCID: PMC7824444 DOI: 10.3390/cells10010027] [Citation(s) in RCA: 155] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/18/2020] [Accepted: 12/22/2020] [Indexed: 12/11/2022] Open
Abstract
Gastric cancer constitutes one of the most prevalent malignancies in both sexes; it is currently the fourth major cause of cancer-related deaths worldwide. The pathogenesis of gastric cancer is associated with the interaction between genetic and environmental factors, among which infection by Helicobacter pylori (H. pylori) is of major importance. The invasion, survival, colonization, and stimulation of further inflammation within the gastric mucosa are possible due to several evasive mechanisms induced by the virulence factors that are expressed by the bacterium. The knowledge concerning the mechanisms of H. pylori pathogenicity is crucial to ameliorate eradication strategies preventing the possible induction of carcinogenesis. This review highlights the current state of knowledge and the most recent findings regarding H. pylori virulence factors and their relationship with gastric premalignant lesions and further carcinogenesis.
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Affiliation(s)
- Jacek Baj
- Department of Anatomy, Medical University of Lublin, 20-400 Lublin, Poland;
| | - Alicja Forma
- Chair and Department of Forensic Medicine, Medical University of Lublin, 20-090 Lublin, Poland;
| | - Monika Sitarz
- Department of Conservative Dentistry with Endodontics, Medical University of Lublin, 20-090 Lublin, Poland;
| | - Piero Portincasa
- Clinica Medica “Augusto Murri”, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70124 Bari, Italy;
| | - Gabriella Garruti
- Section of Endocrinology, Department of Emergency and Organ Transplantations, University of Bari “Aldo Moro” Medical School, Piazza G. Cesare 11, 70124 Bari, Italy;
| | - Danuta Krasowska
- Department of Dermatology, Venerology and Paediatric Dermatology of Medical University of Lublin, 20-081 Lublin, Poland;
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15
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Structural Conservation and Adaptation of the Bacterial Flagella Motor. Biomolecules 2020; 10:biom10111492. [PMID: 33138111 PMCID: PMC7693769 DOI: 10.3390/biom10111492] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 02/07/2023] Open
Abstract
Many bacteria require flagella for the ability to move, survive, and cause infection. The flagellum is a complex nanomachine that has evolved to increase the fitness of each bacterium to diverse environments. Over several decades, molecular, biochemical, and structural insights into the flagella have led to a comprehensive understanding of the structure and function of this fascinating nanomachine. Notably, X-ray crystallography, cryo-electron microscopy (cryo-EM), and cryo-electron tomography (cryo-ET) have elucidated the flagella and their components to unprecedented resolution, gleaning insights into their structural conservation and adaptation. In this review, we focus on recent structural studies that have led to a mechanistic understanding of flagellar assembly, function, and evolution.
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16
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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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17
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Sukri A, Hanafiah A, Mohamad Zin N, Kosai NR. Epidemiology and role of Helicobacter pylori virulence factors in gastric cancer carcinogenesis. APMIS 2020; 128:150-161. [PMID: 32352605 DOI: 10.1111/apm.13034] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 02/09/2020] [Indexed: 02/06/2023]
Abstract
Infection with Helicobacter pylori is associated with the development of gastric cancer. Although the prevalence of gastric cancer has declined throughout years due to improvement in early screening strategy, mortality due to gastric cancer has not changed. Incidence and mortality due to gastric cancer are higher in developing countries as compared to developed countries. Diagnosis and prognosis of gastric cancer are still poor with patients usually diagnosed with cancer at an advanced stage. Eradication of H. pylori is pertinent for the prevention of gastric cancer. However, the rise in antimicrobial resistance among H. pylori isolates has complicated the prevention strategy. H. pylori express multiple virulence factors for survival in the hostile acid gastric environment. The expression of oncogenic protein cytotoxin-associated gene A (CagA), vacuolating cytotoxin A (VacA), and outer inflammatory protein is essential for H. pylori to exert pathogenesis towards the host. Interestingly, <3% of H. pylori-infected subjects develop gastric cancer, suggesting a unique way of interaction between the host's immune response and H. pylori virulence factors. This article is aimed to review the epidemiology and role of H. pylori in gastric carcinogenesis. A better understanding of the interaction between H. pylori virulence factors and host is required for better gastric cancer prevention.
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Affiliation(s)
- Asif Sukri
- Programme of Biomedical Science, Faculty of Health Science, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Alfizah Hanafiah
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Noraziah Mohamad Zin
- Programme of Biomedical Science, Faculty of Health Science, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Nik Ritza Kosai
- Department of Surgery, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
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18
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Taylor JA, Bratton BP, Sichel SR, Blair KM, Jacobs HM, DeMeester KE, Kuru E, Gray J, Biboy J, VanNieuwenhze MS, Vollmer W, Grimes CL, Shaevitz JW, Salama NR. Distinct cytoskeletal proteins define zones of enhanced cell wall synthesis in Helicobacter pylori. eLife 2020; 9:52482. [PMID: 31916938 PMCID: PMC7012605 DOI: 10.7554/elife.52482] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 01/07/2020] [Indexed: 12/15/2022] Open
Abstract
Helical cell shape is necessary for efficient stomach colonization by Helicobacter pylori, but the molecular mechanisms for generating helical shape remain unclear. The helical centerline pitch and radius of wild-type H. pylori cells dictate surface curvatures of considerably higher positive and negative Gaussian curvatures than those present in straight- or curved-rod H. pylori. Quantitative 3D microscopy analysis of short pulses with either N-acetylmuramic acid or D-alanine metabolic probes showed that cell wall growth is enhanced at both sidewall curvature extremes. Immunofluorescence revealed MreB is most abundant at negative Gaussian curvature, while the bactofilin CcmA is most abundant at positive Gaussian curvature. Strains expressing CcmA variants with altered polymerization properties lose helical shape and associated positive Gaussian curvatures. We thus propose a model where CcmA and MreB promote PG synthesis at positive and negative Gaussian curvatures, respectively, and that this patterning is one mechanism necessary for maintaining helical shape. Round spheres, straight rods, and twisting corkscrews, bacteria come in many different shapes. The shape of bacteria is dictated by their cell wall, the strong outer barrier of the cell. As bacteria grow and multiply, they must add to their cell wall while keeping the same basic shape. The cells walls are made from long chain-like molecules via processes that are guided by protein scaffolds within the cell. Many common antibiotics, including penicillin, stop bacterial infections by interrupting the growth of cell walls. Helicobacter pylori is a common bacterium that lives in the gut and, after many years, can cause stomach ulcers and stomach cancer. H. pylori are shaped in a twisting helix, much like a corkscrew. This shape helps H. pylori to take hold and colonize the stomach. It remains unclear how H. pylori creates and maintains its helical shape. The helix is much more curved than other bacteria, and H. pylori does not have the same helpful proteins that other curved bacteria do. If H. pylori grows asymmetrically, adding more material to the cell wall on its long outer side to create a twisting helix, what controls the process? To find out, Taylor et al. grew H. pylori cells and watched how the cell walls took shape. First, a fluorescent dye was attached to the building blocks of the cell wall or to underlying proteins that were thought to help direct its growth. The cells were then imaged in 3D, and images from hundreds of cells were reconstructed to analyze the growth patterns of the bacteria’s cell wall. A protein called CcmA was found most often on the long side of the twisting H. pylori. When the CcmA protein was isolated in a dish, it spontaneously formed sheets and helical bundles, confirming its role as a structural scaffold for the cell wall. When CcmA was absent from the cell of H. pylori, Taylor et al. observed that the pattern of cell growth changed substantially. This work identifies a key component directing the growth of the cell wall of H. pylori and therefore, a new target for antibiotics. Its helical shape is essential for H. pylori to infect the gut, so blocking the action of the CcmA protein may interrupt cell wall growth and prevent stomach infections.
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Affiliation(s)
- Jennifer A Taylor
- Department of Microbiology, University of Washington, Seattle, United States.,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Benjamin P Bratton
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, United States.,Department of Molecular Biology, Princeton University, Princeton, United States
| | - Sophie R Sichel
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Molecular Medicine and Mechanisms of Disease Graduate Program, University of Washington, Seattle, United States
| | - Kris M Blair
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, United States
| | - Holly M Jacobs
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, United States
| | - Kristen E DeMeester
- Department of Chemistry and Biochemistry, University of Delaware, Newark, United States
| | - Erkin Kuru
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Joe Gray
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jacob Biboy
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Catherine L Grimes
- Department of Chemistry and Biochemistry, University of Delaware, Newark, United States.,Department of Biological Sciences, University of Delaware, Newark, United States
| | - Joshua W Shaevitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, United States.,Department of Physics, Princeton University, Princeton, United States
| | - Nina R Salama
- Department of Microbiology, University of Washington, Seattle, United States.,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Molecular Medicine and Mechanisms of Disease Graduate Program, University of Washington, Seattle, United States.,Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, United States
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19
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Henderson LD, Matthews-Palmer TRS, Gulbronson CJ, Ribardo DA, Beeby M, Hendrixson DR. Diversification of Campylobacter jejuni Flagellar C-Ring Composition Impacts Its Structure and Function in Motility, Flagellar Assembly, and Cellular Processes. mBio 2020; 11:e02286-19. [PMID: 31911488 PMCID: PMC6946799 DOI: 10.1128/mbio.02286-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 11/19/2019] [Indexed: 12/22/2022] Open
Abstract
Bacterial flagella are reversible rotary motors that rotate external filaments for bacterial propulsion. Some flagellar motors have diversified by recruiting additional components that influence torque and rotation, but little is known about the possible diversification and evolution of core motor components. The mechanistic core of flagella is the cytoplasmic C ring, which functions as a rotor, directional switch, and assembly platform for the flagellar type III secretion system (fT3SS) ATPase. The C ring is composed of a ring of FliG proteins and a helical ring of surface presentation of antigen (SPOA) domains from the switch proteins FliM and one of two usually mutually exclusive paralogs, FliN or FliY. We investigated the composition, architecture, and function of the C ring of Campylobacter jejuni, which encodes FliG, FliM, and both FliY and FliN by a variety of interrogative approaches. We discovered a diversified C. jejuni C ring containing FliG, FliM, and both FliY, which functions as a classical FliN-like protein for flagellar assembly, and FliN, which has neofunctionalized into a structural role. Specific protein interactions drive the formation of a more complex heterooligomeric C. jejuni C-ring structure. We discovered that this complex C ring has additional cellular functions in polarly localizing FlhG for numerical regulation of flagellar biogenesis and spatial regulation of division. Furthermore, mutation of the C. jejuni C ring revealed a T3SS that was less dependent on its ATPase complex for assembly than were other systems. Our results highlight considerable evolved flagellar diversity that impacts motor output, biogenesis, and cellular processes in different species.IMPORTANCE The conserved core of bacterial flagellar motors reflects a shared evolutionary history that preserves the mechanisms essential for flagellar assembly, rotation, and directional switching. In this work, we describe an expanded and diversified set of core components in the Campylobacter jejuni flagellar C ring, the mechanistic core of the motor. Our work provides insight into how usually conserved core components may have diversified by gene duplication, enabling a division of labor of the ancestral protein between the two new proteins, acquisition of new roles in flagellar assembly and motility, and expansion of the function of the flagellum beyond motility, including spatial regulation of cell division and numerical control of flagellar biogenesis in C. jejuni Our results highlight that relatively small changes, such as gene duplications, can have substantial ramifications on the cellular roles of a molecular machine.
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Affiliation(s)
- Louie D Henderson
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | | | - Connor J Gulbronson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Deborah A Ribardo
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - David R Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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20
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Hanafiah A, Lopes BS. Genetic diversity and virulence characteristics of Helicobacter pylori isolates in different human ethnic groups. INFECTION GENETICS AND EVOLUTION 2019; 78:104135. [PMID: 31837482 DOI: 10.1016/j.meegid.2019.104135] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 12/03/2019] [Accepted: 12/06/2019] [Indexed: 02/07/2023]
Abstract
Helicobacter pylori is the most predominant bacterium in almost 50% of the world's population and colonization causes a persistent inflammatory response leading to chronic gastritis. It shows high genetic diversity and individuals generally harbour a distinct bacterial population. With the advancement of whole-genome sequencing technology, new H. pylori subpopulations have been identified that show admixture between various H. pylori strains. Genotypic variation of H. pylori may be related to the presence of virulence factors among strains and is associated with different outcomes of infection in different individuals. This review summarizes the genetic diversity in H. pylori strain populations and its virulence characteristics responsible for variable outcomes in different ethnic groups.
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Affiliation(s)
- Alfizah Hanafiah
- Department of Medical Microbiology & Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, 56000 Cheras, Kuala Lumpur, Malaysia.
| | - Bruno S Lopes
- Department of Medical Microbiology, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, 0:025 Polwarth Building, Aberdeen AB25 2ZD, United Kingdom.
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21
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Gupta N, Maurya S, Verma H, Verma VK. Unraveling the factors and mechanism involved in persistence: Host-pathogen interactions in Helicobacter pylori. J Cell Biochem 2019; 120:18572-18587. [PMID: 31237031 DOI: 10.1002/jcb.29201] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Accepted: 05/20/2019] [Indexed: 12/15/2022]
Abstract
Helicobacter pylori and humans have one of the most complex relationships in nature. How a bacterium manages to live in one of the harshest and hostile environments is a topic of unraveling mysteries. H. pylori is a prevalent species and it colonizes the human gut of more than 50% of the world population. It infects the epithelial region of antrum and persists there for a long period. Over the time of evolution, H. pylori has developed complex strategies to extend the degree of inflammation in gastric mucosa. H. pylori needs specific adaptations for initial colonization into the host environment like helical shape, flagellar movement, chemotaxis, and the production of urease enzyme that neutralizes acidic environment of the stomach. There are several factors from the bacterium as well as from the host that participate in these complex interactions. On the other hand, to establish the persistent infection, H. pylori escapes the immune system by mimicking the host antigens. This pathogen has the ability to dodge the immune system and then persist there in the form of host cell, which leads to immune tolerance. H. pylori has an ability to manipulate its own pathogen-associated molecular patterns, which leads to an inhibition in the binding with specific pattern recognition receptors of the host to avoid immune cell detection. Also, it manipulates the host metabolic homeostasis in the gastric epithelium. Besides, it has several genes, which may get involved in the acquisition of nutrition from the host to survive longer in the host. Due to the persistence of H. pylori, it causes chronic inflammation and raises the chances of gastric cancer. This review highlights the important elements, which are certainly responsible for the persistence of H. pylori in the human host.
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Affiliation(s)
- Nidhi Gupta
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Kishangarh, India
| | - Shweta Maurya
- Department of Microbiology, School of Life Sciences, Central University of Rajasthan, Kishangarh, India
| | - Harshvardhan Verma
- Department of Microbiology, School of Life Sciences, Central University of Rajasthan, Kishangarh, India
| | - Vijay K Verma
- Department of Microbiology, School of Life Sciences, Central University of Rajasthan, Kishangarh, India
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22
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A Genome-Wide Helicobacter pylori Morphology Screen Uncovers a Membrane-Spanning Helical Cell Shape Complex. J Bacteriol 2019; 201:JB.00724-18. [PMID: 31036730 DOI: 10.1128/jb.00724-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 04/26/2019] [Indexed: 12/16/2022] Open
Abstract
Evident in its name, the gastric pathogen Helicobacter pylori has a helical cell morphology which facilitates efficient colonization of the human stomach. An improved light-focusing strategy allowed us to robustly distinguish even subtle perturbations of H. pylori cell morphology by deviations in light-scattering properties measured by flow cytometry. Profiling of an arrayed genome-wide deletion library identified 28 genes that influence different aspects of cell shape, including properties of the helix, cell length or width, cell filament formation, cell shape heterogeneity, and cell branching. Included in this mutant collection were two that failed to form any helical cells, a soluble lytic transglycosylase and a previously uncharacterized putative multipass inner membrane protein HPG27_0728, renamed Csd7. A combination of cell fractionation, mutational, and immunoprecipitation experiments show that Csd7 and Csd2 collaborate to stabilize the Csd1 peptidoglycan (PG) endopeptidase. Thus, both csd2 and csd7 mutants show the same enhancement of PG tetra-pentapeptide cross-linking as csd1 mutants. Csd7 also links Csd1 with the bactofilin CcmA via protein-protein interactions. Although Csd1 is stable in ccmA mutants, these mutants show altered PG tetra-pentapeptide cross-linking, suggesting that Csd7 may directly or indirectly activate as well as stabilize Csd1. These data begin to illuminate a highly orchestrated program to regulate PG modifications that promote helical shape, which includes nine nonessential nonredundant genes required for helical shape and 26 additional genes that further modify H. pylori's cell morphology.IMPORTANCE The stomach ulcer and cancer-causing pathogen Helicobacter pylori has a helical cell shape which facilitates stomach infection. Using light scattering to measure perturbations of cell morphology, we identified 28 genes that influence different aspects of cell shape. A mutant in a previously uncharacterized protein renamed Csd7 failed to form any helical cells. Biochemical analyses showed that Csd7 collaborates with other proteins to stabilize the cell wall-degrading enzyme Csd1. Csd7 also links Csd1 with a putative filament-forming protein via protein-protein interactions. These data suggest that helical cell shape arises from a highly orchestrated program to regulate cell wall modifications. Targeting of this helical cell shape-promoting program could offer new ways to block infectivity of this important human pathogen.
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23
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Nonhelical Helicobacter pylori Mutants Show Altered Gland Colonization and Elicit Less Gastric Pathology than Helical Bacteria during Chronic Infection. Infect Immun 2019; 87:IAI.00904-18. [PMID: 31061142 DOI: 10.1128/iai.00904-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/26/2019] [Indexed: 12/13/2022] Open
Abstract
Half of all humans harbor Helicobacter pylori in their stomachs. Helical cell shape is thought to facilitate H. pylori's ability to bore into the protective mucus layer in a corkscrew-like motion, thereby enhancing colonization of the stomach. H. pylori cell shape mutants show impaired colonization of the mouse stomach, highlighting the importance of cell shape in infection. To gain a deeper understanding of how helical cell morphology promotes host colonization by H. pylori, we used three-dimensional confocal microscopy to visualize the clinical isolate PMSS1 and an isogenic straight-rod mutant (Δcsd6) within thick longitudinal mouse stomach sections. We also performed volumetric image analysis to quantify the number of bacteria residing within corpus and antral glands in addition to measuring total CFU. We found that straight rods show attenuation during acute colonization of the stomach (1 day or 1 week postinfection) as measured by total CFU. Our quantitative imaging revealed that wild-type bacteria extensively colonized antral glands at 1 week postinfection, while csd6 mutants showed variable colonization of the antrum at this time point. During chronic infection (1 or 3 months postinfection), total CFU were highly variable but similar for wild-type and straight rods. Both wild-type and straight rods persisted and expanded in corpus glands during chronic infection. However, the straight rods showed reduced inflammation and disease progression. Thus, helical cell shape contributes to tissue interactions that promote inflammation during chronic infection, in addition to facilitating niche acquisition during acute infection.
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24
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Taylor JA, Sichel SR, Salama NR. Bent Bacteria: A Comparison of Cell Shape Mechanisms in Proteobacteria. Annu Rev Microbiol 2019; 73:457-480. [PMID: 31206344 DOI: 10.1146/annurev-micro-020518-115919] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Helical cell shape appears throughout the bacterial phylogenetic tree. Recent exciting work characterizing cell shape mutants in a number of curved and helical Proteobacteria is beginning to suggest possible mechanisms and provide tools to assess functional significance. We focus here on Caulobacter crescentus, Vibrio cholerae, Helicobacter pylori, and Campylobacter jejuni, organisms from three classes of Proteobacteria that live in diverse environments, from freshwater and saltwater to distinct compartments within the gastrointestinal tract of humans and birds. Comparisons among these bacteria reveal common themes as well as unique solutions to the task of maintaining cell curvature. While motility appears to be influenced in all these bacteria when cell shape is perturbed, consequences on niche colonization are diverse, suggesting the need to consider additional selective pressures.
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Affiliation(s)
- Jennifer A Taylor
- Department of Microbiology, University of Washington, Seattle, Washington 98195, USA; .,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | - Sophie R Sichel
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.,Molecular Medicine and Mechanisms of Disease Graduate Program, University of Washington, Seattle, Washington 98195, USA
| | - Nina R Salama
- Department of Microbiology, University of Washington, Seattle, Washington 98195, USA; .,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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25
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Helicobacter pylori Biofilm Involves a Multigene Stress-Biased Response, Including a Structural Role for Flagella. mBio 2018; 9:mBio.01973-18. [PMID: 30377283 PMCID: PMC6212823 DOI: 10.1128/mbio.01973-18] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Biofilms, communities of bacteria that are embedded in a hydrated matrix of extracellular polymeric substances, pose a substantial health risk and are key contributors to many chronic and recurrent infections. Chronicity and recalcitrant infections are also common features associated with the ulcer-causing human pathogen H. pylori. However, relatively little is known about the role of biofilms in H. pylori pathogenesis, as well as the biofilm structure itself and the genes associated with this mode of growth. In the present study, we found that H. pylori biofilm cells highly expressed genes related to cell envelope and stress response, as well as those encoding the flagellar apparatus. Flagellar filaments were seen in high abundance in the biofilm. Flagella are known to play a role in initial biofilm formation, but typically are downregulated after that state. H. pylori instead appears to have coopted these structures for nonmotility roles, including a role building a robust biofilm. Helicobacter pylori has an impressive ability to persist chronically in the human stomach. Similar characteristics are associated with biofilm formation in other bacteria. The H. pylori biofilm process, however, is poorly understood. To gain insight into this mode of growth, we carried out comparative transcriptomic analysis between H. pylori biofilm and planktonic cells, using the mouse-colonizing strain SS1. Optimal biofilm formation was obtained with a low concentration of serum and 3 days of growth, conditions that caused both biofilm and planktonic cells to be ∼80% coccoid. Transcriptome sequencing (RNA-seq) analysis found that 8.18% of genes were differentially expressed between biofilm and planktonic cell transcriptomes. Biofilm-downregulated genes included those involved in metabolism and translation, suggesting these cells have low metabolic activity. Biofilm-upregulated genes included those whose products were predicted to be at the cell envelope, involved in regulating a stress response, and surprisingly, genes related to formation of the flagellar apparatus. Scanning electron microscopy visualized flagella that appeared to be a component of the biofilm matrix, supported by the observation that an aflagellated mutant displayed a less robust biofilm with no apparent filaments. We observed flagella in the biofilm matrix of additional H. pylori strains, supporting that flagellar use is widespread. Our data thus support a model in which H. pylori biofilm involves a multigene stress-biased response and that flagella play an important role in H. pylori biofilm formation.
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Dyer V, Brüggemann H, Sörensen M, Kühl AA, Hoffman K, Brinkmann V, Reines MDM, Zimmerman S, Meyer TF, Koch M. Genomic features of the Helicobacter pylori strain PMSS1 and its virulence attributes as deduced from its in vivo colonisation patterns. Mol Microbiol 2018; 110:761-776. [PMID: 30230643 DOI: 10.1111/mmi.14123] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 08/27/2018] [Accepted: 09/05/2018] [Indexed: 12/19/2022]
Abstract
The human gastric pathogen Helicobacter pylori occurs in two basic variants, either exhibiting a functional cagPAI-encoded type-4-secretion-system (T4SS) or not. Only a few cagPAI-positive strains have been successfully adapted for long-term infection of mice, including the pre-mouse Sydney strain 1 (PMSS1). Here we confirm that PMSS1 induces gastric inflammation and neutrophil infiltration in mice, progressing to intestinal metaplasia. Complete genome analysis of PMSS1 revealed 1,423 coding sequences, encompassing the cagPAI gene cluster and, unusually, the location of the cytotoxin-associated gene A (cagA) approximately 15 kb downstream of the island. PMSS1 harbours three genetically exchangeable loci that are occupied by the hopQ coding sequences. HopQ represents a critical co-factor required for the translocation of CagA into the host cell and activation of NF-κB via the T4SS. Long-term colonisation of mice led to an impairment of cagPAI functionality. One of the bacterial clones re-isolated at four months post-infection revealed a mutation in the cagPAI gene cagW, resulting in a frame shift mutation, which prevented CagA translocation, possibly due to an impairment of T4SS function. Rescue of the mutant cagW re-established CagA translocation. Our data reveal intriguing insights into the adaptive abilities of PMSS1, suggesting functional modulation of the H. pylori cagPAI virulence attribute.
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Affiliation(s)
- Victoria Dyer
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, 10117, Germany
| | - Holger Brüggemann
- Department of Biomedicine, Aarhus University, Aarhus C, 8000, Denmark
| | - Meike Sörensen
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, 10117, Germany
| | - Anja A Kühl
- Division of Gastroenterology, Infectiology and Rheumatology, Medical Department, Campus Benjamin Franklin, Charité, Berlin, 12200, Germany
| | - Kirstin Hoffman
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, 10117, Germany
| | - Volker Brinkmann
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, 10117, Germany
| | - Maria Del Mar Reines
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, 10117, Germany
| | - Stephanie Zimmerman
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, 10117, Germany
| | - Thomas F Meyer
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, 10117, Germany
| | - Manuel Koch
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, 10117, Germany
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Lam KH, Xue C, Sun K, Zhang H, Lam WWL, Zhu Z, Ng JTY, Sause WE, Lertsethtakarn P, Lau KF, Ottemann KM, Au SWN. Three SpoA-domain proteins interact in the creation of the flagellar type III secretion system in Helicobacter pylori. J Biol Chem 2018; 293:13961-13973. [PMID: 29991595 PMCID: PMC6130963 DOI: 10.1074/jbc.ra118.002263] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 06/07/2018] [Indexed: 01/07/2023] Open
Abstract
Bacterial flagella are rotary nanomachines that contribute to bacterial fitness in many settings, including host colonization. The flagellar motor relies on the multiprotein flagellar motor-switch complex to govern flagellum formation and rotational direction. Different bacteria exhibit great diversity in their flagellar motors. One such variation is exemplified by the motor-switch apparatus of the gastric pathogen Helicobacter pylori, which carries an extra switch protein, FliY, along with the more typical FliG, FliM, and FliN proteins. All switch proteins are needed for normal flagellation and motility in H. pylori, but the molecular mechanism of their assembly is unknown. To fill this gap, we examined the interactions among these proteins. We found that the C-terminal SpoA domain of FliY (FliYC) is critical to flagellation and forms heterodimeric complexes with the FliN and FliM SpoA domains, which are β-sheet domains of type III secretion system proteins. Surprisingly, unlike in other flagellar switch systems, neither FliY nor FliN self-associated. The crystal structure of the FliYC-FliNC complex revealed a saddle-shaped structure homologous to the FliN-FliN dimer of Thermotoga maritima, consistent with a FliY-FliN heterodimer forming the functional unit. Analysis of the FliYC-FliNC interface indicated that oppositely charged residues specific to each protein drive heterodimer formation. Moreover, both FliYC-FliMC and FliYC-FliNC associated with the flagellar regulatory protein FliH, explaining their important roles in flagellation. We conclude that H. pylori uses a FliY-FliN heterodimer instead of a homodimer and creates a switch complex with SpoA domains derived from three distinct proteins.
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Affiliation(s)
- Kwok Ho Lam
- From the Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Chaolun Xue
- From the Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong, ,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China, and
| | - Kailei Sun
- From the Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Huawei Zhang
- From the Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong, ,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China, and
| | - Wendy Wai Ling Lam
- From the Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong, ,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China, and
| | - Zeyu Zhu
- From the Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Juliana Tsz Yan Ng
- From the Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong
| | - William E. Sause
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California 95064
| | - Paphavee Lertsethtakarn
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California 95064
| | - Kwok Fai Lau
- From the Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Karen M. Ottemann
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California 95064
| | - Shannon Wing Ngor Au
- From the Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong, ,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China, and ,To whom correspondence should be addressed. Tel.:
852-3943-4170; E-mail:
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Isaeva G, Valieva R. Biological characteristics and virulence of Helicobacter pylori. CLINICAL MICROBIOLOGY AND ANTIMICROBIAL CHEMOTHERAPY 2018. [DOI: 10.36488/cmac.2018.1.14-23] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2023]
Abstract
This review summarizes the most recent data on the biological characteristics of Helicobacter pylori (morphological, cultural, biochemical). H. pylori pathogenicity factors promoting colonization, adhesion, biofilm formation, aggression, and cytotoxicity, their contribution to the pathogenesis of diseases as well as the possible relationships with various clinical outcomes are described in detail. The genetic heterogeneity of H. pylori strains which can determine different clinical manifestations and have significance for conducting epidemiological studies is also considered.
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Affiliation(s)
- G.Sh. Isaeva
- Kazan Research Institute of Epidemiology and Microbiology; Kazan State Medical University (Kazan, Russia)
| | - R.I. Valieva
- Kazan Research Institute of Epidemiology and Microbiology; KazanState Medical University (Kazan, Russia)
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Xue C, Lam KH, Zhang H, Sun K, Lee SH, Chen X, Au SWN. Crystal structure of the FliF-FliG complex from Helicobacter pylori yields insight into the assembly of the motor MS-C ring in the bacterial flagellum. J Biol Chem 2017; 293:2066-2078. [PMID: 29229777 DOI: 10.1074/jbc.m117.797936] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 11/28/2017] [Indexed: 11/06/2022] Open
Abstract
The bacterial flagellar motor is a self-assembling supramolecular nanodevice. Its spontaneous biosynthesis is initiated by the insertion of the MS ring protein FliF into the inner membrane, followed by attachment of the switch protein FliG. Assembly of this multiprotein complex is tightly regulated to avoid nonspecific aggregation, but the molecular mechanisms governing flagellar assembly are unclear. Here, we present the crystal structure of the cytoplasmic domain of FliF complexed with the N-terminal domain of FliG (FliF C -FliG N ) from the bacterium Helicobacter pylori Within this complex, FliF C interacted with FliG N through extensive hydrophobic contacts similar to those observed in the FliF C -FliG N structure from the thermophile Thermotoga maritima, indicating conservation of the FliF C -FliG N interaction across bacterial species. Analysis of the crystal lattice revealed that the heterodimeric complex packs as a linear superhelix via stacking of the armadillo repeat-like motifs (ARM) of FliG N Notably, this linear helix was similar to that observed for the assembly of the FliG middle domain. We validated the in vivo relevance of the FliG N stacking by complementation studies in Escherichia coli Furthermore, structural comparison with apo FliG from the thermophile Aquifex aeolicus indicated that FliF regulates the conformational transition of FliG and exposes the complementary ARM-like motifs of FliG N , containing conserved hydrophobic residues. FliF apparently both provides a template for FliG polymerization and spatiotemporally controls subunit interactions within FliG. Our findings reveal that a small protein fold can serve as a versatile building block to assemble into a multiprotein machinery of distinct shapes for specific functions.
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Affiliation(s)
- Chaolun Xue
- From the Center for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Kwok Ho Lam
- From the Center for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Huawei Zhang
- From the Center for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Kailei Sun
- From the Center for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Sai Hang Lee
- From the Center for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Xin Chen
- From the Center for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Shannon Wing Ngor Au
- From the Center for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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30
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Johnson KS, Ottemann KM. Colonization, localization, and inflammation: the roles of H. pylori chemotaxis in vivo. Curr Opin Microbiol 2017; 41:51-57. [PMID: 29202336 DOI: 10.1016/j.mib.2017.11.019] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/27/2017] [Accepted: 11/16/2017] [Indexed: 12/18/2022]
Abstract
Helicobacter pylori is a Gram-negative bacterium that infects half of the world's population, causing gastritis, peptic ulcers, and gastric cancer. To establish chronic stomach infection, H. pylori utilizes chemotaxis, driven by a conserved signal transduction system. Chemotaxis allows H. pylori to sense an array of environmental and bacterial signals within the stomach, guiding its motility towards its preferred niche within the gastric mucosa and glands. Fine-tuned localization, regulated by the chemotaxis system, enables robust colonization during the acute stage of infection. During chronic infection, chemotaxis helps maintain bacterial populations and modulates the host immune response. Given its importance in host colonization and disease, chemotaxis is an attractive target for future treatments against H. pylori infections.
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Affiliation(s)
- Kevin S Johnson
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Karen M Ottemann
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, Santa Cruz, CA 95064, USA.
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31
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Zhang H, Lam KH, Lam WWL, Wong SYY, Chan VSF, Au SWN. A putative spermidine synthase interacts with flagellar switch protein FliM and regulates motility inHelicobacter pylori. Mol Microbiol 2017; 106:690-703. [DOI: 10.1111/mmi.13829] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2017] [Indexed: 12/25/2022]
Affiliation(s)
- Huawei Zhang
- Centre for Protein Science and Crystallography, School of Life Sciences; The Chinese University of Hong Kong; Hong Kong
| | - Kwok Ho Lam
- Centre for Protein Science and Crystallography, School of Life Sciences; The Chinese University of Hong Kong; Hong Kong
| | - Wendy Wai Ling Lam
- Centre for Protein Science and Crystallography, School of Life Sciences; The Chinese University of Hong Kong; Hong Kong
| | - Sandra Yuen Yuen Wong
- Division of Rheumatology & Clinical Immunology, Department of Medicine, Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong
| | - Vera Sau Fong Chan
- Division of Rheumatology & Clinical Immunology, Department of Medicine, Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong
| | - Shannon Wing Ngor Au
- Centre for Protein Science and Crystallography, School of Life Sciences; The Chinese University of Hong Kong; Hong Kong
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32
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Gu H. Role of Flagella in the Pathogenesis of Helicobacter pylori. Curr Microbiol 2017; 74:863-869. [PMID: 28444418 PMCID: PMC5447363 DOI: 10.1007/s00284-017-1256-4] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 04/18/2017] [Indexed: 12/15/2022]
Abstract
This review aimed to investigate the role of Helicobacter pylori flagella on the pathogenicity of this bacterium in humans. Helicobacter pylori is a flagellated pathogen that colonizes the human gastroduodenal mucosa and produces inflammation, and is responsible for gastrointestinal disease. Its pathogenesis is attributed to colonization and virulence factors. The primary function of H. pylori flagella is to provide motility. We believe that H. pylori flagella play an important role in the colonization of the gastrointestinal mucosa. Therefore, we reviewed previous studies on flagellar morphology and motility in order to explore the relationship between H. pylori flagella and pathogenicity. Further investigation is required to confirm the association between flagella and pathogenicity in H. pylori.
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Affiliation(s)
- Haiying Gu
- Medical School, Ningbo University, Ningbo, 315211, China.
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33
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The Helicobacter pylori Autotransporter ImaA Tempers the Bacterium's Interaction with α5β1 Integrin. Infect Immun 2016; 85:IAI.00450-16. [PMID: 27795352 DOI: 10.1128/iai.00450-16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 10/07/2016] [Indexed: 02/07/2023] Open
Abstract
The human pathogen Helicobacter pylori uses the host receptor α5β1 integrin to trigger inflammation in host cells via its cag pathogenicity island (cag PAI) type IV secretion system (T4SS). Here, we report that the H. pylori ImaA protein (HP0289) decreases the action of the cag PAI T4SS via tempering the bacterium's interaction with α5β1 integrin. Previously, imaA-null mutants were found to induce an elevated inflammatory response that was dependent on the cag PAI T4SS; here we extend those findings to show that the elevated response is independent of the CagA effector protein. To understand how ImaA could be affecting cag PAI T4SS activity at the host cell interface, we utilized the Phyre structural threading program and found that ImaA has a region with remote homology to bacterial integrin-binding proteins. This region was required for ImaA function. Unexpectedly, we observed that imaA mutants bound higher levels of α5β1 integrin than wild-type H. pylori, an outcome that required the predicted integrin-binding homology region of ImaA. Lastly, we report that ImaA directly affected the amount of host cell β1 integrin but not other cellular integrins. Our results thus suggest a model in which H. pylori employs ImaA to regulate interactions between integrin and the T4SS and thus alter the host inflammatory strength.
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34
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Imaging the motility and chemotaxis machineries in Helicobacter pylori by cryo-electron tomography. J Bacteriol 2016; 199:e00695-16. [PMID: 27849173 DOI: 10.1128/jb.00695-16] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Helicobacter pylori is a bacterial pathogen that can cause many gastrointestinal diseases including ulcers and gastric cancer. A unique chemotaxis-mediated motility is critical for H. pylori to colonize in the human stomach and to establish chronic infection, but the underlying molecular mechanisms are not well understood. Here we employ cryo-electron tomography to reveal detailed structures of the H. pylori cell envelope including the sheathed flagella and chemotaxis arrays. Notably, H. pylori possesses a distinctive periplasmic cage-like structure with 18-fold symmetry. We propose that this structure forms a robust platform for recruiting 18 torque generators, which likely provide the higher torque needed for swimming in high-viscosity environments. We also reveal a series of key flagellar assembly intermediates, providing structural evidence that flagellar assembly is tightly coupled with biogenesis of the membrane sheath. Finally, we determine the structure of putative chemotaxis arrays at the flagellar pole, which have implications for how direction of flagellar rotation is regulated. Together, our pilot cryo-ET studies provide novel structural insights into the unipolar flagella of H. pylori and lay a foundation for a better understanding of the unique motility of this organism. IMPORTANCE Helicobacter pylori is a highly motile bacterial pathogen that colonizes approximately 50% of the world's population. H. pylori can move readily within the viscous mucosal layer of the stomach. It has become increasingly clear that its unique flagella-driven motility is essential for successful gastric colonization and pathogenesis. Here we use advanced imaging techniques to visualize novel in situ structures with unprecedented detail in intact H. pylori cells. Remarkably, H. pylori possesses multiple unipolar flagella, which are driven by one of the largest flagellar motors found in bacteria. These large motors presumably provide higher torque needed by the bacterial pathogens to navigate in viscous environment of the human stomach.
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Constantino MA, Jabbarzadeh M, Fu HC, Bansil R. Helical and rod-shaped bacteria swim in helical trajectories with little additional propulsion from helical shape. SCIENCE ADVANCES 2016; 2:e1601661. [PMID: 28138539 PMCID: PMC5262464 DOI: 10.1126/sciadv.1601661] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/12/2016] [Indexed: 05/17/2023]
Abstract
It has frequently been hypothesized that the helical body shapes of flagellated bacteria may yield some advantage in swimming ability. In particular, the helical-shaped pathogen Helicobacter pylori is often claimed to swim like a corkscrew through its harsh gastric habitat, but there has been no direct confirmation or quantification of such claims. Using fast time-resolution and high-magnification two-dimensional (2D) phase-contrast microscopy to simultaneously image and track individual bacteria in bacterial broth as well as mucin solutions, we show that both helical and rod-shaped H. pylori rotated as they swam, producing a helical trajectory. Cell shape analysis enabled us to determine shape as well as the rotational and translational speed for both forward and reverse motions, thereby inferring flagellar kinematics. Using the method of regularized Stokeslets, we directly compare observed speeds and trajectories to numerical calculations for both helical and rod-shaped bacteria in mucin and broth to validate the numerical model. Although experimental observations are limited to select cases, the model allows quantification of the effects of body helicity, length, and diameter. We find that due to relatively slow body rotation rates, the helical shape makes at most a 15% contribution to propulsive thrust. The effect of body shape on swimming speeds is instead dominated by variations in translational drag required to move the cell body. Because helical cells are one of the strongest candidates for propulsion arising from the cell body, our results imply that quite generally, swimming speeds of flagellated bacteria can only be increased a little by body propulsion.
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Affiliation(s)
| | - Mehdi Jabbarzadeh
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - Henry C. Fu
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112, USA
- Corresponding author. (H.C.F.); (R.B.)
| | - Rama Bansil
- Department of Physics, Boston University, Boston MA 02215, USA
- Corresponding author. (H.C.F.); (R.B.)
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Analysis of a Spontaneous Non-Motile and Avirulent Mutant Shows That FliM Is Required for Full Endoflagella Assembly in Leptospira interrogans. PLoS One 2016; 11:e0152916. [PMID: 27044038 PMCID: PMC4820103 DOI: 10.1371/journal.pone.0152916] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 03/21/2016] [Indexed: 11/19/2022] Open
Abstract
Pathogenic Leptospira strains are responsible for leptospirosis, a worldwide emerging zoonotic disease. These spirochetes are unique amongst bacteria because of their corkscrew-like cell morphology and their periplasmic flagella. Motility is reported as an important virulence determinant, probably favoring entry and dissemination of pathogenic Leptospira in the host. However, proteins constituting the periplasmic flagella and their role in cell shape, motility and virulence remain poorly described. In this study, we characterized a spontaneous L. interrogans mutant strain lacking motility, correlated with the loss of the characteristic hook-shaped ends, and virulence in the animal model. Whole genome sequencing allowed the identification of one nucleotide deletion in the fliM gene resulting in a premature stop codon, thereby preventing the production of flagellar motor switch protein FliM. Genetic complementation restored cell morphology, motility and virulence comparable to those of wild type cells. Analyses of purified periplasmic flagella revealed a defect in flagella assembly, resulting in shortened flagella compared to the wild type strain. This also correlated with a lower amount of major filament proteins FlaA and FlaB. Altogether, these findings demonstrate that FliM is required for full and correct assembly of the flagella which is essential for motility and virulence.
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Keilberg D, Ottemann KM. HowHelicobacter pylorisenses, targets and interacts with the gastric epithelium. Environ Microbiol 2016; 18:791-806. [DOI: 10.1111/1462-2920.13222] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 01/05/2016] [Accepted: 01/10/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Daniela Keilberg
- Department of Microbiology and Environmental Toxicology; University of California Santa Cruz; 1156 High Street METX Santa Cruz CA 95064 USA
| | - Karen M. Ottemann
- Department of Microbiology and Environmental Toxicology; University of California Santa Cruz; 1156 High Street METX Santa Cruz CA 95064 USA
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38
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Martinez LE, Hardcastle JM, Wang J, Pincus Z, Tsang J, Hoover TR, Bansil R, Salama NR. Helicobacter pylori strains vary cell shape and flagellum number to maintain robust motility in viscous environments. Mol Microbiol 2016; 99:88-110. [PMID: 26365708 PMCID: PMC4857613 DOI: 10.1111/mmi.13218] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2015] [Indexed: 12/24/2022]
Abstract
The helical shape of the human stomach pathogen Helicobacter pylori has been suggested to provide mechanical advantage for penetrating the viscous stomach mucus layer. Using single-cell tracking and quantitative morphology analysis, we document marked variation in cell body helical parameters and flagellum number among H. pylori strains leading to distinct and broad speed distributions in broth and viscous gastric mucin media. These distributions reflect both temporal variation in swimming speed and morphologic variation within the population. Isogenic mutants with straight-rod morphology showed 7-21% reduction in speed and a lower fraction of motile bacteria. Mutational perturbation of flagellum number revealed a 19% increase in speed with 4 versus 3 median flagellum number. Resistive force theory modeling incorporating variation of both cell shape and flagellum number predicts qualitative speed differences of 10-30% among strains. However, quantitative comparisons suggest resistive force theory underestimates the influence of cell body shape on speed for helical shaped bacteria.
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Affiliation(s)
- Laura E. Martinez
- Graduate Program in Pathobiology, Department of Global Health, University of Washington, Seattle, WA 98195 USA
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109 USA
| | | | - Jeffrey Wang
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109 USA
| | - Zachary Pincus
- Department of Developmental Biology and Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jennifer Tsang
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Timothy R. Hoover
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Rama Bansil
- Department of Physics, Boston University, Boston, MA 02215 USA
| | - Nina R. Salama
- Graduate Program in Pathobiology, Department of Global Health, University of Washington, Seattle, WA 98195 USA
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109 USA
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Pandini A, Kleinjung J, Rasool S, Khan S. Coevolved Mutations Reveal Distinct Architectures for Two Core Proteins in the Bacterial Flagellar Motor. PLoS One 2015; 10:e0142407. [PMID: 26561852 PMCID: PMC4642947 DOI: 10.1371/journal.pone.0142407] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 10/21/2015] [Indexed: 02/08/2023] Open
Abstract
Switching of bacterial flagellar rotation is caused by large domain movements of the FliG protein triggered by binding of the signal protein CheY to FliM. FliG and FliM form adjacent multi-subunit arrays within the basal body C-ring. The movements alter the interaction of the FliG C-terminal (FliGC) “torque” helix with the stator complexes. Atomic models based on the Salmonella entrovar C-ring electron microscopy reconstruction have implications for switching, but lack consensus on the relative locations of the FliG armadillo (ARM) domains (amino-terminal (FliGN), middle (FliGM) and FliGC) as well as changes during chemotaxis. The generality of the Salmonella model is challenged by the variation in motor morphology and response between species. We studied coevolved residue mutations to determine the unifying elements of switch architecture. Residue interactions, measured by their coevolution, were formalized as a network, guided by structural data. Our measurements reveal a common design with dedicated switch and motor modules. The FliM middle domain (FliMM) has extensive connectivity most simply explained by conserved intra and inter-subunit contacts. In contrast, FliG has patchy, complex architecture. Conserved structural motifs form interacting nodes in the coevolution network that wire FliMM to the FliGC C-terminal, four-helix motor module (C3-6). FliG C3-6 coevolution is organized around the torque helix, differently from other ARM domains. The nodes form separated, surface-proximal patches that are targeted by deleterious mutations as in other allosteric systems. The dominant node is formed by the EHPQ motif at the FliMMFliGM contact interface and adjacent helix residues at a central location within FliGM. The node interacts with nodes in the N-terminal FliGc α-helix triad (ARM-C) and FliGN. ARM-C, separated from C3-6 by the MFVF motif, has poor intra-network connectivity consistent with its variable orientation revealed by structural data. ARM-C could be the convertor element that provides mechanistic and species diversity.
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Affiliation(s)
- Alessandro Pandini
- Department of Computer Science and Synthetic Biology Theme, Brunel University London, Uxbridge UB8 3PH, United Kingdom
| | - Jens Kleinjung
- Mathematical Biology, Francis Crick Institute, Ridgeway, Mill Hill, London NW7 1AA, United Kingdom
| | - Shafqat Rasool
- Department of Biochemistry, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Shahid Khan
- Molecular Biology Consortium, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States of America
- * E-mail:
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Lertsethtakarn P, Howitt MR, Castellon J, Amieva MR, Ottemann KM. Helicobacter pylori CheZ(HP) and ChePep form a novel chemotaxis-regulatory complex distinct from the core chemotaxis signaling proteins and the flagellar motor. Mol Microbiol 2015; 97:1063-78. [PMID: 26061894 DOI: 10.1111/mmi.13086] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2015] [Indexed: 12/20/2022]
Abstract
Chemotaxis is important for Helicobacter pylori to colonize the stomach. Like other bacteria, H. pylori uses chemoreceptors and conserved chemotaxis proteins to phosphorylate the flagellar rotational response regulator, CheY, and modulate the flagellar rotational direction. Phosphorylated CheY is returned to its non-phosphorylated state by phosphatases such as CheZ. In previously studied cases, chemotaxis phosphatases localize to the cellular poles by interactions with either the CheA chemotaxis kinase or flagellar motor proteins. We report here that the H. pylori CheZ, CheZ(HP), localizes to the poles independently of the flagellar motor, CheA, and all typical chemotaxis proteins. Instead, CheZ(HP) localization depends on the chemotaxis regulatory protein ChePep, and reciprocally, ChePep requires CheZ(HP) for its polar localization. We furthermore show that these proteins interact directly. Functional domain mapping of CheZ(HP) determined the polar localization motif lies within the central domain of the protein and that the protein has regions outside of the active site that participate in chemotaxis. Our results suggest that CheZ(HP) and ChePep form a distinct complex. These results therefore suggest the intriguing idea that some phosphatases localize independently of the other chemotaxis and motility proteins, possibly to confer unique regulation on these proteins' activities.
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Affiliation(s)
- Paphavee Lertsethtakarn
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA, 95064, USA
| | - Michael R Howitt
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Juan Castellon
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA, 95064, USA
| | - Manuel R Amieva
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Karen M Ottemann
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA, 95064, USA
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Basal Body Structures Differentially Affect Transcription of RpoN- and FliA-Dependent Flagellar Genes in Helicobacter pylori. J Bacteriol 2015; 197:1921-30. [PMID: 25825427 DOI: 10.1128/jb.02533-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/20/2015] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED Flagellar biogenesis in Helicobacter pylori is regulated by a transcriptional hierarchy governed by three sigma factors, RpoD (σ(80)), RpoN (σ(54)), and FliA (σ(28)), that temporally coordinates gene expression with the assembly of the flagellum. Previous studies showed that loss of flagellar protein export apparatus components inhibits transcription of flagellar genes. The FlgS/FlgR two-component system activates transcription of RpoN-dependent genes though an unknown mechanism. To understand better the extent to which flagellar gene regulation is coupled to flagellar assembly, we disrupted flagellar biogenesis at various points and determined how these mutations affected transcription of RpoN-dependent (flaB and flgE) and FliA-dependent (flaA) genes. The MS ring (encoded by fliF) is one of the earliest flagellar structures assembled. Deletion of fliF resulted in the elimination of RpoN-dependent transcripts and an ∼4-fold decrease in flaA transcript levels. FliH is a cytoplasmic protein that functions with the C ring protein FliN to shuttle substrates to the export apparatus. Deletions of fliH and genes encoding C ring components (fliM and fliY) decreased transcript levels of flaB and flgE but had little or no effect on transcript levels of flaA. Transcript levels of flaB and flgE were elevated in mutants where genes encoding rod proteins (fliE and flgBC) were deleted, while transcript levels of flaA was reduced ∼2-fold in both mutants. We propose that FlgS responds to an assembly checkpoint associated with the export apparatus and that FliH and one or more C ring component assist FlgS in engaging this flagellar structure. IMPORTANCE The mechanisms used by bacteria to couple transcription of flagellar genes with assembly of the flagellum are poorly understood. The results from this study identified components of the H. pylori flagellar basal body that either positively or negatively affect expression of RpoN-dependent flagellar genes. Some of these basal body proteins may interact directly with regulatory proteins that control transcription of the H. pylori RpoN regulon, a hypothesis that can be tested by examining protein-protein interactions in vitro.
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Bartfeld S, Bayram T, van de Wetering M, Huch M, Begthel H, Kujala P, Vries R, Peters PJ, Clevers H. In vitro expansion of human gastric epithelial stem cells and their responses to bacterial infection. Gastroenterology 2015; 148:126-136.e6. [PMID: 25307862 PMCID: PMC4274199 DOI: 10.1053/j.gastro.2014.09.042] [Citation(s) in RCA: 543] [Impact Index Per Article: 60.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 09/23/2014] [Accepted: 09/24/2014] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS We previously established long-term, 3-dimensional culture of organoids from mouse tissues (intestine, stomach, pancreas, and liver) and human intestine and pancreas. Here we describe conditions required for long-term 3-dimensional culture of human gastric stem cells. The technology can be applied to study the epithelial response to infection with Helicobacter pylori. METHODS We generated organoids from surgical samples of human gastric corpus. Culture conditions were developed based on those for the mouse gastric and human intestinal systems. We used microinjection to infect the organoids with H pylori. Epithelial responses were measured using microarray and quantitative polymerase chain reaction analyses. RESULTS Human gastric cells were expanded indefinitely in 3-dimensional cultures. We cultured cells from healthy gastric tissues, single-sorted stem cells, or tumor tissues. Organoids maintained many characteristics of their respective tissues based on their histology, expression of markers, and euploidy. Organoids from healthy tissue expressed markers of 4 lineages of the stomach and self-organized into gland and pit domains. They could be directed to specifically express either lineages of the gastric gland, or the gastric pit, by addition of nicotinamide and withdrawal of WNT. Although gastric pit lineages had only marginal reactions to bacterial infection, gastric gland lineages mounted a strong inflammatory response. CONCLUSIONS We developed a system to culture human gastric organoids. This system can be used to study H pylori infection and other gastric pathologies.
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Affiliation(s)
- Sina Bartfeld
- Hubrecht Institute for Developmental Biology and Stem Cell Research and University Medical Centre Utrecht, Utrecht, The Netherlands.
| | - Tülay Bayram
- Hubrecht Institute for Developmental Biology and Stem Cell Research & University Medical Centre Utrecht, 3584 CT Utrecht, the Netherlands, CancerGenomics.nl
| | - Marc van de Wetering
- Hubrecht Institute for Developmental Biology and Stem Cell Research & University Medical Centre Utrecht, 3584 CT Utrecht, the Netherlands, CancerGenomics.nl
| | - Meritxell Huch
- Hubrecht Institute for Developmental Biology and Stem Cell Research & University Medical Centre Utrecht, 3584 CT Utrecht, the Netherlands, CancerGenomics.nl
| | - Harry Begthel
- Hubrecht Institute for Developmental Biology and Stem Cell Research & University Medical Centre Utrecht, 3584 CT Utrecht, the Netherlands, CancerGenomics.nl
| | - Pekka Kujala
- Division of Cell Biology II, Antoni van Leeuwenhoek Hospital/Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Robert Vries
- Hubrecht Institute for Developmental Biology and Stem Cell Research & University Medical Centre Utrecht, 3584 CT Utrecht, the Netherlands, CancerGenomics.nl
| | - Peter J Peters
- Division of Cell Biology II, Antoni van Leeuwenhoek Hospital/Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Hans Clevers
- Hubrecht Institute for Developmental Biology and Stem Cell Research & University Medical Centre Utrecht, 3584 CT Utrecht, the Netherlands, CancerGenomics.nl
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Shewanella oneidensis MR-1 nanowires are outer membrane and periplasmic extensions of the extracellular electron transport components. Proc Natl Acad Sci U S A 2014; 111:12883-8. [PMID: 25143589 DOI: 10.1073/pnas.1410551111] [Citation(s) in RCA: 352] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacterial nanowires offer an extracellular electron transport (EET) pathway for linking the respiratory chain of bacteria to external surfaces, including oxidized metals in the environment and engineered electrodes in renewable energy devices. Despite the global, environmental, and technological consequences of this biotic-abiotic interaction, the composition, physiological relevance, and electron transport mechanisms of bacterial nanowires remain unclear. We report, to our knowledge, the first in vivo observations of the formation and respiratory impact of nanowires in the model metal-reducing microbe Shewanella oneidensis MR-1. Live fluorescence measurements, immunolabeling, and quantitative gene expression analysis point to S. oneidensis MR-1 nanowires as extensions of the outer membrane and periplasm that include the multiheme cytochromes responsible for EET, rather than pilin-based structures as previously thought. These membrane extensions are associated with outer membrane vesicles, structures ubiquitous in Gram-negative bacteria, and are consistent with bacterial nanowires that mediate long-range EET by the previously proposed multistep redox hopping mechanism. Redox-functionalized membrane and vesicular extensions may represent a general microbial strategy for electron transport and energy distribution.
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Motility and chemotaxis mediate the preferential colonization of gastric injury sites by Helicobacter pylori. PLoS Pathog 2014; 10:e1004275. [PMID: 25033386 PMCID: PMC4102597 DOI: 10.1371/journal.ppat.1004275] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 06/10/2014] [Indexed: 01/22/2023] Open
Abstract
Helicobacter pylori (H. pylori) is a pathogen contributing to peptic inflammation, ulceration, and cancer. A crucial step in the pathogenic sequence is when the bacterium first interacts with gastric tissue, an event that is poorly understood in vivo. We have shown that the luminal space adjacent to gastric epithelial damage is a microenvironment, and we hypothesized that this microenvironment might enhance H. pylori colonization. Inoculation with 106H. pylori (wild-type Sydney Strain 1, SS1) significantly delayed healing of acetic-acid induced ulcers at Day 1, 7 and 30 post-inoculation, and wild-type SS1 preferentially colonized the ulcerated area compared to uninjured gastric tissue in the same animal at all time points. Gastric resident Lactobacillus spp. did not preferentially colonize ulcerated tissue. To determine whether bacterial motility and chemotaxis are important to ulcer healing and colonization, we analyzed isogenic H. pylori mutants defective in motility (ΔmotB) or chemotaxis (ΔcheY). ΔmotB (106) failed to colonize ulcerated or healthy stomach tissue. ΔcheY (106) colonized both tissues, but without preferential colonization of ulcerated tissue. However, ΔcheY did modestly delay ulcer healing, suggesting that chemotaxis is not required for this process. We used two-photon microscopy to induce microscopic epithelial lesions in vivo, and evaluated accumulation of fluorescently labeled H. pylori at gastric damage sites in the time frame of minutes instead of days. By 5 min after inducing damage, H. pylori SS1 preferentially accumulated at the site of damage and inhibited gastric epithelial restitution. H. pylori ΔcheY modestly accumulated at the gastric surface and inhibited restitution, but did not preferentially accumulate at the injury site. H. pylori ΔmotB neither accumulated at the surface nor inhibited restitution. We conclude that bacterial chemosensing and motility rapidly promote H. pylori colonization of injury sites, and thereby biases the injured tissue towards sustained gastric damage. H. pylori is a disease-causing bacterium that commonly infects the human stomach in both developed and underdeveloped countries. Infected individuals can develop digestive diseases, including stomach inflammation, peptic ulcer, and cancer. There has been only limited investigation into the events when H. pylori first interacts with stomach tissue. Using anesthetized mice in which we have induced microscopic damage to the stomach surface, we find that H. pylori is able to rapidly detect and navigate towards this damage site. Within minutes, bacterial accumulation slows repair of the damage. This is the earliest event of H. pylori pathogenesis that has been reported in vivo. We further define that this pathology is due to the bacterial accumulation at damage sites and that this also occurs in a model of larger stomach damage (ulceration). The broader implications of our work are that even sub-clinical insults to the stomach that occur in daily life (damage from grinding of food, ingestion of alcohol, taking an aspirin) can potentially attract H. pylori and not only slow repair of any existing damage, but maybe also provide an initiation site that can start the pathogenic sequence of stomach disease caused by H. pylori.
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Tsang J, Hoover TR. Themes and Variations: Regulation of RpoN-Dependent Flagellar Genes across Diverse Bacterial Species. SCIENTIFICA 2014; 2014:681754. [PMID: 24672734 PMCID: PMC3930126 DOI: 10.1155/2014/681754] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 12/16/2013] [Indexed: 06/03/2023]
Abstract
Flagellar biogenesis in bacteria is a complex process in which the transcription of dozens of structural and regulatory genes is coordinated with the assembly of the flagellum. Although the overall process of flagellar biogenesis is conserved among bacteria, the mechanisms used to regulate flagellar gene expression vary greatly among different bacterial species. Many bacteria use the alternative sigma factor σ (54) (also known as RpoN) to transcribe specific sets of flagellar genes. These bacteria include members of the Epsilonproteobacteria (e.g., Helicobacter pylori and Campylobacter jejuni), Gammaproteobacteria (e.g., Vibrio and Pseudomonas species), and Alphaproteobacteria (e.g., Caulobacter crescentus). This review characterizes the flagellar transcriptional hierarchies in these bacteria and examines what is known about how flagellar gene regulation is linked with other processes including growth phase, quorum sensing, and host colonization.
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Affiliation(s)
- Jennifer Tsang
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Timothy R. Hoover
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
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Sycuro LK, Rule CS, Petersen TW, Wyckoff TJ, Sessler T, Nagarkar DB, Khalid F, Pincus Z, Biboy J, Vollmer W, Salama NR. Flow cytometry-based enrichment for cell shape mutants identifies multiple genes that influence Helicobacter pylori morphology. Mol Microbiol 2013; 90:869-83. [PMID: 24112477 PMCID: PMC3844677 DOI: 10.1111/mmi.12405] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2013] [Indexed: 12/17/2022]
Abstract
The helical cell shape of Helicobacter pylori is highly conserved and contributes to its ability to swim through and colonize the viscous gastric mucus layer. A multi-faceted peptidoglycan (PG) modification programme involving four recently characterized peptidases and two accessory proteins is essential for maintaining H. pylori's helicity. To expedite identification of additional shape-determining genes, we employed flow cytometry with fluorescence-activated cell sorting (FACS) to enrich a transposon library for bacterial cells with altered light scattering profiles that correlate with perturbed cell morphology. After a single round of sorting, 15% of our clones exhibited a stable cell shape defect, reflecting 37-fold enrichment. Sorted clones with straight rod morphology contained insertions in known PG peptidases, as well as an insertion in csd6, which we demonstrated has ld-carboxypeptidase activity and cleaves monomeric tetrapeptides in the PG sacculus, yielding tripeptides. Other mutants had only slight changes in helicity due to insertions in genes encoding MviN/MurJ, a protein possibly involved in initiating PG synthesis, and the hypothetical protein HPG27_782. Our findings demonstrate FACS robustly detects perturbations of bacterial cell shape and identify additional PG peptide modifications associated with helical cell shape in H. pylori.
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Affiliation(s)
- Laura K Sycuro
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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Sircar R, Greenswag AR, Bilwes AM, Gonzalez-Bonet G, Crane BR. Structure and activity of the flagellar rotor protein FliY: a member of the CheC phosphatase family. J Biol Chem 2013; 288:13493-502. [PMID: 23532838 PMCID: PMC3650386 DOI: 10.1074/jbc.m112.445171] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND FliY is a flagellar rotor protein of the CheC phosphatase family. RESULTS The FliY structure resembles that of the rotor protein FliM but contains two active centers for CheY dephosphorylation. CONCLUSION FliY incorporates properties of the FliM/FliN rotor proteins and the CheC/CheX phosphatases to serve multiple functions in the flagellar switch. SIGNIFICANCE FliY distinguishes flagellar architecture and function in different types of bacteria. Rotating flagella propel bacteria toward favorable environments. Sense of rotation is determined by the intracellular response regulator CheY, which when phosphorylated (CheY-P) interacts directly with the flagellar motor. In many different types of bacteria, the CheC/CheX/FliY (CXY) family of phosphatases terminates the CheY-P signal. Unlike CheC and CheX, FliY is localized in the flagellar switch complex, which also contains the stator-coupling protein FliG and the target of CheY-P, FliM. The 2.5 Å resolution crystal structure of the FliY catalytic domain from Thermotoga maritima bears strong resemblance to the middle domain of FliM. Regions of FliM that mediate contacts within the rotor compose the phosphatase active sites in FliY. Despite the similarity between FliY and FliM, FliY does not bind FliG and thus is unlikely to be a substitute for FliM in the center of the switch complex. Solution studies indicate that FliY dimerizes through its C-terminal domains, which resemble the Escherichia coli switch complex component FliN. FliY differs topologically from the E. coli chemotaxis phosphatase CheZ but appears to utilize similar structural motifs for CheY dephosphorylation in close analogy to CheX. Recognition properties and phosphatase activities of site-directed mutants identify two pseudosymmetric active sites in FliY (Glu(35)/Asn(38) and Glu(132)/Asn(135)), with the second site (Glu(132)/Asn(135)) being more active. A putative N-terminal CheY binding domain conserved with FliM is not required for binding CheY-P or phosphatase activity.
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Affiliation(s)
- Ria Sircar
- From the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850
| | - Anna R. Greenswag
- From the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850
| | - Alexandrine M. Bilwes
- From the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850
| | - Gabriela Gonzalez-Bonet
- From the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850
| | - Brian R. Crane
- From the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, To whom correspondence should be addressed: Dept. of Chemistry and Chemical Biology Cornell University, Ithaca, NY 14850. Tel.: 607-254-8634; E-mail:
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Lam KH, Lam WWL, Wong JYK, Chan LC, Kotaka M, Ling TKW, Jin DY, Ottemann KM, Au SWN. Structural basis of FliG-FliM interaction inHelicobacter pylori. Mol Microbiol 2013; 88:798-812. [DOI: 10.1111/mmi.12222] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2013] [Indexed: 12/20/2022]
Affiliation(s)
- Kwok-Ho Lam
- Center for Protein Science and Crystallography; School of Life Sciences; The Chinese University of Hong Kong; Hong Kong; China
| | - Wendy Wai Ling Lam
- Center for Protein Science and Crystallography; School of Life Sciences; The Chinese University of Hong Kong; Hong Kong; China
| | - Jase Yan-Kit Wong
- Center for Protein Science and Crystallography; School of Life Sciences; The Chinese University of Hong Kong; Hong Kong; China
| | - Ling-Chim Chan
- Department of Biochemistry; The University of Hong Kong; Hong Kong; China
| | - Masayo Kotaka
- Department of Physiology; The University of Hong Kong; Hong Kong; China
| | - Thomas Kin-Wah Ling
- Department of Microbiology; The Chinese University of Hong Kong; Hong Kong; China
| | - Dong-Yan Jin
- Department of Biochemistry; The University of Hong Kong; Hong Kong; China
| | - Karen M. Ottemann
- Department of Microbiology and Environmental Toxicology; University of California Santa Cruz; Santa Cruz; CA; USA
| | - Shannon Wing-Ngor Au
- Center for Protein Science and Crystallography; School of Life Sciences; The Chinese University of Hong Kong; Hong Kong; China
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The Helicobacter pylori autotransporter ImaA (HP0289) modulates the immune response and contributes to host colonization. Infect Immun 2012; 80:2286-96. [PMID: 22566509 DOI: 10.1128/iai.00312-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The human pathogen Helicobacter pylori employs a diverse collection of outer membrane proteins to colonize, persist, and drive disease within the acidic gastric environment. In this study, we sought to elucidate the function of the host-induced gene HP0289, which encodes an uncharacterized outer membrane protein. We first generated an isogenic H. pylori mutant that lacks HP0289 and found that the mutant has a colonization defect in single-strain infections and is greatly outcompeted in mouse coinfection experiments with wild-type H. pylori. Furthermore, we used protease assays and biochemical fractionation coupled with an HP0289-targeted peptide antibody to verify that the HP0289 protein resides in the outer membrane. Our previous findings showed that the HP0289 promoter is upregulated in the mouse stomach, and here we demonstrate that HP0289 expression is induced under acidic conditions in an ArsRS-dependent manner. Finally, we have shown that the HP0289 mutant induces greater expression of the chemokine interleukin-8 (IL-8) and the cytokine tumor necrosis factor alpha (TNF-α) in gastric carcinoma cells (AGS). Similarly, transcription of the IL-8 homolog keratinocyte-derived chemokine (KC) is elevated in murine infections with the HP0289 mutant than in murine infections with wild-type H. pylori. On the basis of this phenotype, we renamed HP0289 ImaA for immunomodulatory autotransporter protein. Our work has revealed that genes induced in vivo play an important role in H. pylori pathogenesis. Specifically, the outer membrane protein ImaA modulates a component of the host inflammatory response, and thus may allow H. pylori to fine tune the host immune response based on ImaA expression.
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50
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Sycuro LK, Wyckoff TJ, Biboy J, Born P, Pincus Z, Vollmer W, Salama NR. Multiple peptidoglycan modification networks modulate Helicobacter pylori's cell shape, motility, and colonization potential. PLoS Pathog 2012; 8:e1002603. [PMID: 22457625 PMCID: PMC3310797 DOI: 10.1371/journal.ppat.1002603] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 01/05/2012] [Indexed: 12/14/2022] Open
Abstract
Helical cell shape of the gastric pathogen Helicobacter pylori has been suggested to promote virulence through viscosity-dependent enhancement of swimming velocity. However, H. pylori csd1 mutants, which are curved but lack helical twist, show normal velocity in viscous polymer solutions and the reason for their deficiency in stomach colonization has remained unclear. Characterization of new rod shaped mutants identified Csd4, a DL-carboxypeptidase of peptidoglycan (PG) tripeptide monomers and Csd5, a putative scaffolding protein. Morphological and biochemical studies indicated Csd4 tripeptide cleavage and Csd1 crosslinking relaxation modify the PG sacculus through independent networks that coordinately generate helical shape. csd4 mutants show attenuation of stomach colonization, but no change in proinflammatory cytokine induction, despite four-fold higher levels of Nod1-agonist tripeptides in the PG sacculus. Motility analysis of similarly shaped mutants bearing distinct alterations in PG modifications revealed deficits associated with shape, but only in gel-like media and not viscous solutions. As gastric mucus displays viscoelastic gel-like properties, our results suggest enhanced penetration of the mucus barrier underlies the fitness advantage conferred by H. pylori's characteristic shape.
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Affiliation(s)
- Laura K. Sycuro
- Molecular and Cellular Biology Graduate Program, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Timna J. Wyckoff
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Division of Science and Mathematics, University of Minnesota, Morris, Minnesota, United States of America
| | - Jacob Biboy
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Petra Born
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Zachary Pincus
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Nina R. Salama
- Molecular and Cellular Biology Graduate Program, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- * E-mail:
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