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Keith BA, Harding JCS, Loewen ME. Mutational analysis of TlyA from Brachyspira hampsonii reveals two key residues conserved in pathogenic bacteria responsible for oligomerization and hemolytic activity. Biochim Biophys Acta Gen Subj 2021; 1866:130045. [PMID: 34715264 DOI: 10.1016/j.bbagen.2021.130045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 10/07/2021] [Accepted: 10/22/2021] [Indexed: 12/01/2022]
Abstract
BACKGROUND TlyA proteins are expressed in a variety of pathogenic bacteria and possess dual hemolytic and ribosomal RNA methyltransferase functions. While the mechanism of TlyA mediated rRNA methylation is well understood, relatively little is known about the mechanism of TlyA induced hemolysis. METHODS TlyA protein from the pig pathogen Brachyspira hampsonii was heterologously expressed and purified from an E. coli host. Hemolytic activity and rRNA methylation were assessed in vitro. Site-directed mutagenesis was used to mutate amino acids believed to be involved in TlyA mediated hemolysis. RESULTS Purified TlyA-His protein exhibited both hemolytic and rRNA methyltransferase activities in vitro, with partial inhibition of hemolysis observed under reducing conditions. Mutation of cysteine 80 to alanine impaired hemolytic activity. A C27A/C93A mutant was capable of dimerizing under non-reducing conditions, indicating that a C80-C80 disulfide bond is involved in TlyA oligomerization. A mutation conserved in several avirulent Brachyspira species (S9K) completely abolished hemolytic activity of TlyA. This loss of activity was attributed to impaired oligomerization in the S9K mutant, as assessed by ITC and size-exclusion chromatography experiments. CONCLUSIONS Oligomeric assembly and hemolytic activity of TlyA from Brachyspira hampsonii is dependent on the formation of an intermolecular C80-C80 disulfide bond and noncovalent interactions involving serine 9. The conservation of these amino acids in TlyA proteins from pathogenic bacteria suggests a correlation between tlyA gene mutations and bacterial virulence. GENERAL SIGNIFICANCE Our results further elucidate the mechanisms underlying TlyA mediated hemolysis and provide evidence of a conserved mechanism of oligomerization for TlyA family proteins.
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Affiliation(s)
- Brandon A Keith
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
| | - John C S Harding
- Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Matthew E Loewen
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.
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2
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Prakosa AW, Miftahussurur M, Juniastuti J, Waskito LA, Doohan D, Fauzia KA, Rezkitha YAA, Sugihartono T, Syam AF, Uchida T, Yamaoka Y. Characterization of Helicobacter pylori tlyA and Its Association with Bacterial Density. Dig Dis 2021; 40:417-426. [PMID: 34515099 DOI: 10.1159/000518538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/19/2021] [Indexed: 02/02/2023]
Abstract
BACKGROUND In the recent studies, a less virulent Helicobacter pylori variant could still colonize the human stomach and induce gastric inflammation, suggesting the involvement of other virulence factors, such as TlyA hemolysin. Nevertheless, the association of TlyA in the pathogenesis of H. pylori infection remains unclear. We investigated the tlyA profile and determined its relationship with gastritis severity. METHODS An observational study was conducted using DNA stocks and secondary data from previous studies. The tlyA variant was examined by NGS and confirmed with polymerase chain reaction. Gastritis severity was categorized by the Updated Sydney System. The relationship between a variant of tlyA and gastritis severity was determined, in which discrete variables were tested using the χ2 test or Fisher exact test. RESULTS Two H. pylori tlyA variants were observed and characterized as tlyA1 and tlyA2. We noted a unique variant in the amino acid sequence 32-35 that is exclusively detected among H. pylori isolated from the Papua island. In addition, we observed that the tlyA variant had a significant association with the H. pylori density in the antral (p = 0.002). Histological analyses revealed that TlyA1 was associated with higher H. pylori density than TlyA2. However, we did not observe any significant association of tlyA with the infiltration of inflammation cells. CONCLUSIONS We observed 2 tlyA variants (tlyA1 and tlyA2). A significant association of tlyA with bacterial density suggested that tlyA plays a more significant role in the colonization process than its influence on the severity of inflammation in gastric mucosa.
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Affiliation(s)
- Adi Wasis Prakosa
- Faculty of Medicine, Universitas Airlangga, Surabaya, Indonesia.,Universitas Airlangga Teaching Hospital, Surabaya, Indonesia
| | - Muhammad Miftahussurur
- Gastroentero-Hepatology Division, Department of Internal Medicine, Faculty of Medicine, Universitas Airlangga-Dr. Soetomo Teaching Hospital, Surabaya, Indonesia.,Institute of Tropical Disease, Universitas Airlangga, Surabaya, Indonesia.,Department of Environmental and Preventive Medicine, Faculty of Medicine, Oita University, Yufu, Japan
| | | | - Langgeng Agung Waskito
- Institute of Tropical Disease, Universitas Airlangga, Surabaya, Indonesia.,Department of Environmental and Preventive Medicine, Faculty of Medicine, Oita University, Yufu, Japan
| | - Dalla Doohan
- Institute of Tropical Disease, Universitas Airlangga, Surabaya, Indonesia.,Department of Environmental and Preventive Medicine, Faculty of Medicine, Oita University, Yufu, Japan
| | - Kartika Afrida Fauzia
- Institute of Tropical Disease, Universitas Airlangga, Surabaya, Indonesia.,Department of Environmental and Preventive Medicine, Faculty of Medicine, Oita University, Yufu, Japan
| | - Yudith Annisa Ayu Rezkitha
- Institute of Tropical Disease, Universitas Airlangga, Surabaya, Indonesia.,Faculty of Medicine, University of Muhammadiyah Surabaya, Surabaya, Indonesia
| | - Titong Sugihartono
- Gastroentero-Hepatology Division, Department of Internal Medicine, Faculty of Medicine, Universitas Airlangga-Dr. Soetomo Teaching Hospital, Surabaya, Indonesia
| | - Ari Fahrial Syam
- Division of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia
| | - Tomohisa Uchida
- Department of Molecular Pathology, Faculty of Medicine, Oita University, Yufu, Japan
| | - Yoshio Yamaoka
- Gastroentero-Hepatology Division, Department of Internal Medicine, Faculty of Medicine, Universitas Airlangga-Dr. Soetomo Teaching Hospital, Surabaya, Indonesia.,Department of Environmental and Preventive Medicine, Faculty of Medicine, Oita University, Yufu, Japan
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3
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Ahmed AAQ, Qi F, Zheng R, Xiao L, Abdalla AME, Mao L, Bakadia BM, Liu L, Atta OM, Li X, Shi Z, Yang G. The impact of ExHp-CD (outer membrane vesicles) released from Helicobacter pylori SS1 on macrophage RAW 264.7 cells and their immunogenic potential. Life Sci 2021; 279:119644. [PMID: 34048813 DOI: 10.1016/j.lfs.2021.119644] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/02/2021] [Accepted: 05/14/2021] [Indexed: 12/11/2022]
Abstract
Bacterial-derived extracellular vesicles could play a major role in attenuating and treating diseases. They play a major anti-infection role by modulating immune responses against pathogens and preventing infection by inhibiting pathogen localization and proliferation. In this study, outer membrane vesicles (ExHp-CD) released by Helicobacter pylori SS1 (H. pylori) and total antigens isolated from H. pylori SS1 (AgHp) were evaluated for their immunogenic potential and their effect on macrophage RAW 264.7 cells. Results demonstrated that both ExHp-CD and AgHp induced T helper 2 (Th2) immune response, which was reported to be important in immune protection against H. pylori infections. Both ExHp-CD and AgHp produced high levels of IL-10 and IL-4, while no significant levels of IL-12 p70 or IFN-γ were detected. However, ExHp-CD showed a better effect on macrophage RAW 264.7 cells compared to AgHp. Macrophage RAW 264.7 cells stimulated with 5, and 10 μg/mL of ExHp-CD showed an increased ratio of CD206 (M2 phenotype marker) and a decreased ratio of CD86 (M1 phenotype marker). Moreover, results suggested that the immunogenic effect that ExHp-CD possesses was attributed to their cargo of Epimerase_2 domain-containing protein (Epi_2D), Probable malate:quinone oxidoreductase (Pro_mqo), and Probable cytosol aminopeptidase (Pro_ca). Results demonstrated that ExHp-CD possesses an immunological activity to induce Th2 immune response against H. pylori infection with results comparable to AgHp. However, ExHp-CD showed higher efficacy regarding safety, biocompatibility, lack of toxicity, and hemocompatibility. Thus, it could serve as an immunogenic candidate with more desired characteristics.
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Affiliation(s)
- Abeer Ahmed Qaed Ahmed
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Fuyu Qi
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Ruizhu Zheng
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Lin Xiao
- School of Biomedical Engineering, Sun Yat-sen University, Guangzhou 510006, China.
| | - Ahmed M E Abdalla
- Department of Biochemistry, College of Applied Science, University of Bahri, Khartoum 1660/11111, Sudan
| | - Lin Mao
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Bianza Moise Bakadia
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Li Liu
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Omar Mohammad Atta
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Xiaohong Li
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Zhijun Shi
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Guang Yang
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China.
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4
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Sałamaszyńska-Guz A, Serafińska I, Bącal P, Douthwaite S. Virulence properties of Campylobacter jejuni are enhanced by displaying a mycobacterial TlyA methylation pattern in its rRNA. Cell Microbiol 2020; 22:e13199. [PMID: 32134554 PMCID: PMC7317525 DOI: 10.1111/cmi.13199] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/24/2020] [Accepted: 02/23/2020] [Indexed: 01/18/2023]
Abstract
Campylobacter jejuni is a bacterial pathogen that is generally acquired as a zoonotic infection from poultry and animals. Adhesion of C. jejuni to human colorectal epithelial cells is weakened after loss of its cj0588 gene. The Cj0588 protein belongs to the type I group of TlyA (TlyAI) enzymes, which 2′‐O‐methylate nucleotide C1920 in 23S rRNA. Slightly longer TlyAII versions of the methyltransferase are found in actinobacterial species including Mycobacterium tuberculosis, and methylate not only C1920 but also nucleotide C1409 in 16S rRNA. Loss of TlyA function attenuates virulence of both M. tuberculosis and C. jejuni. We show here that the traits impaired in C. jejuni null strains can be rescued by complementation not only with the original cj0588 (tlyAI) but also with a mycobacterial tlyAII gene. There are, however, significant differences in the recombinant phenotypes. While cj0588 restores motility, biofilm formation, adhesion to and invasion of human epithelial cells and stimulation of IL‐8 production in a C. jejuni null strain, several of these properties are further enhanced by the mycobacterial tlyAII gene, in some cases to twice the original wild‐type level. These findings strongly suggest that subtle changes in rRNA modification patterns can affect protein synthesis in a manner that has serious consequences for bacterial pathogenicity.
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Affiliation(s)
- Agnieszka Sałamaszyńska-Guz
- Division of Microbiology, Department of Pre-Clinical Sciences, Institute of Veterinary Medicine, Warsaw University of Live Sciences - SGGW, Warsaw, Poland
| | - Izabela Serafińska
- Division of Microbiology, Department of Pre-Clinical Sciences, Institute of Veterinary Medicine, Warsaw University of Live Sciences - SGGW, Warsaw, Poland
| | - Paweł Bącal
- Laboratory of Theory and Applications of Electrodes, Faculty of Chemistry, University of Warsaw, Warsaw, Poland.,Nałęcz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland
| | - Stephen Douthwaite
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
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5
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Samainukul N, Linn AK, Javadi MB, Sakdee S, Angsuthanasombat C, Katzenmeier G. Importance of the Cys 124-Cys 128 intermolecular disulfide bonding for oligomeric assembly and hemolytic activity of the Helicobacter pylori TlyA hemolysin. Biochem Biophys Res Commun 2019; 514:365-371. [PMID: 31040022 DOI: 10.1016/j.bbrc.2019.04.096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 04/13/2019] [Indexed: 01/16/2023]
Abstract
Although the TlyA hemolysin from Helicobacter pylori has been implicated as a potential virulence factor involved in mediating host cell colonization and hence disease progression, its structural determinants underlying the biological activity are still largely uncertain. In this study, an important role of the formation of a particular disulfide bond for functional oligomeric assembly of the H. pylori TlyA toxin was evidently elucidated. The 27-kDa TlyA recombinant protein was overexpressed in Escherichia coli, subsequently purified to near homogeneity by cation exchange chromatography, and proven to be hemolytically active against sheep erythrocytes. Additionally, TlyA-induced hemolytic activity was significantly diminished under conditions of disulfide bond reduction with a thiol-reducing agent, dithiothreitol. When the purified TlyA protein was subjected to modified SDS-PAGE under non-reducing conditions, the presence of an oligomeric state of this protein was clearly revealed by its apparent molecular mass of ∼48 kDa. Recombinant E. coli cells expressing TlyA also displayed contact-dependent hemolysis of erythrocytes, suggesting TlyA localization at the bacterial outer membrane and thus supporting the formation of disulfide-bonded TlyA. Homology-based modeling and in silico structural assembly analysis of TlyA signified potential intermolecular, rather than intramolecular, disulfide bonding through Cys124 and Cys128. Subsequently, single substitution of either of these Cys residues with Ser severely affected the oligomeric assembly of both TlyA mutants and hence abolished their hemolytic activity. Altogether, our present data provide pivotal evidence that the formation of intermolecular disulfide bonding between Cys124 and Cys128 plays a critical role in structural assembly of a biologically active-TlyA oligomer.
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Affiliation(s)
- Nitchakan Samainukul
- Graduate Program in Immunology, Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand; Bacterial Toxin Reseach Innovation Cluster (BRIC), Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom, 73170, Thailand
| | - Aung Khine Linn
- Graduate Program in Immunology, Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand; Bacterial Toxin Reseach Innovation Cluster (BRIC), Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom, 73170, Thailand
| | - Mohammad Bagher Javadi
- Bacterial Toxin Reseach Innovation Cluster (BRIC), Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom, 73170, Thailand
| | - Somsri Sakdee
- Bacterial Toxin Reseach Innovation Cluster (BRIC), Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom, 73170, Thailand
| | - Chanan Angsuthanasombat
- Bacterial Toxin Reseach Innovation Cluster (BRIC), Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom, 73170, Thailand; Division of Biochemistry and Biochemical Technology, Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
| | - Gerd Katzenmeier
- Bacterial Toxin Reseach Innovation Cluster (BRIC), Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom, 73170, Thailand.
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6
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Sałamaszyńska-Guz A, Rose S, Lykkebo CA, Taciak B, Bącal P, Uśpieński T, Douthwaite S. Biofilm Formation and Motility Are Promoted by Cj0588-Directed Methylation of rRNA in Campylobacter jejuni. Front Cell Infect Microbiol 2018; 7:533. [PMID: 29404277 PMCID: PMC5778110 DOI: 10.3389/fcimb.2017.00533] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 12/20/2017] [Indexed: 12/25/2022] Open
Abstract
Numerous bacterial pathogens express an ortholog of the enzyme TlyA, which is an rRNA 2′-O-methyltransferase associated with resistance to cyclic peptide antibiotics such as capreomycin. Several other virulence traits have also been attributed to TlyA, and these appear to be unrelated to its methyltransferase activity. The bacterial pathogen Campylobacter jejuni possesses the TlyA homolog Cj0588, which has been shown to contribute to virulence. Here, we investigate the mechanism of Cj0588 action and demonstrate that it is a type I homolog of TlyA that 2′-O-methylates 23S rRNA nucleotide C1920. This same specific function is retained by Cj0588 both in vitro and also when expressed in Escherichia coli. Deletion of the cj0588 gene in C. jejuni or substitution with alanine of K80, D162, or K188 in the catalytic center of the enzyme cause complete loss of 2′-O-methylation activity. Cofactor interactions remain unchanged and binding affinity to the ribosomal substrate is only slightly reduced, indicating that the inactivated proteins are folded correctly. The substitution mutations thus dissociate the 2′-O-methylation function of Cj0588/TlyA from any other putative roles that the protein might play. C. jejuni strains expressing catalytically inactive versions of Cj0588 have the same phenotype as cj0588-null mutants, and show altered tolerance to capreomycin due to perturbed ribosomal subunit association, reduced motility and impaired ability to form biofilms. These functions are reestablished when methyltransferase activity is restored and we conclude that the contribution of Cj0588 to virulence in C. jejuni is a consequence of the enzyme's ability to methylate its rRNA.
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Affiliation(s)
- Agnieszka Sałamaszyńska-Guz
- Division of Microbiology, Department of Pre-Clinical Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland
| | - Simon Rose
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Claus A Lykkebo
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Bartłomiej Taciak
- Division of Physiology, Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland
| | - Paweł Bącal
- Laboratory of Theory and Applications of Electrodes, Faculty of Chemistry, University of Warsaw, Warsaw, Poland
| | - Tomasz Uśpieński
- Division of Microbiology, Department of Pre-Clinical Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland
| | - Stephen Douthwaite
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
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7
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Cárdenas A, Neave MJ, Haroon MF, Pogoreutz C, Rädecker N, Wild C, Gärdes A, Voolstra CR. Excess labile carbon promotes the expression of virulence factors in coral reef bacterioplankton. ISME JOURNAL 2017; 12:59-76. [PMID: 28895945 PMCID: PMC5739002 DOI: 10.1038/ismej.2017.142] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 07/23/2017] [Accepted: 07/25/2017] [Indexed: 01/01/2023]
Abstract
Coastal pollution and algal cover are increasing on many coral reefs, resulting in higher dissolved organic carbon (DOC) concentrations. High DOC concentrations strongly affect microbial activity in reef waters and select for copiotrophic, often potentially virulent microbial populations. High DOC concentrations on coral reefs are also hypothesized to be a determinant for switching microbial lifestyles from commensal to pathogenic, thereby contributing to coral reef degradation, but evidence is missing. In this study, we conducted ex situ incubations to assess gene expression of planktonic microbial populations under elevated concentrations of naturally abundant monosaccharides (glucose, galactose, mannose, and xylose) in algal exudates and sewage inflows. We assembled 27 near-complete (>70%) microbial genomes through metagenomic sequencing and determined associated expression patterns through metatranscriptomic sequencing. Differential gene expression analysis revealed a shift in the central carbohydrate metabolism and the induction of metalloproteases, siderophores, and toxins in Alteromonas, Erythrobacter, Oceanicola, and Alcanivorax populations. Sugar-specific induction of virulence factors suggests a mechanistic link for the switch from a commensal to a pathogenic lifestyle, particularly relevant during increased algal cover and human-derived pollution on coral reefs. Although an explicit test remains to be performed, our data support the hypothesis that increased availability of specific sugars changes net microbial community activity in ways that increase the emergence and abundance of opportunistic pathogens, potentially contributing to coral reef degradation.
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Affiliation(s)
- Anny Cárdenas
- Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany.,Max Plank Institute for Marine Microbiology, Bremen, Germany.,Red Sea Research Center, Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Matthew J Neave
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Mohamed Fauzi Haroon
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Claudia Pogoreutz
- Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany.,Red Sea Research Center, Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.,Marine Ecology Group, Faculty of Biology and Chemistry, University of Bremen, Germany
| | - Nils Rädecker
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.,Marine Ecology Group, Faculty of Biology and Chemistry, University of Bremen, Germany
| | - Christian Wild
- Marine Ecology Group, Faculty of Biology and Chemistry, University of Bremen, Germany
| | - Astrid Gärdes
- Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany
| | - Christian R Voolstra
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
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8
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Kreuder AJ, Schleining JA, Yaeger M, Zhang Q, Plummer PJ. RNAseq Reveals Complex Response of Campylobacter jejuni to Ovine Bile and In vivo Gallbladder Environment. Front Microbiol 2017; 8:940. [PMID: 28611744 PMCID: PMC5447181 DOI: 10.3389/fmicb.2017.00940] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 05/10/2017] [Indexed: 02/01/2023] Open
Abstract
Colonization of the gallbladder by enteric pathogens such as Salmonella typhi, Listeria monocytogenes, and Campylobacter jejuni is thought to play a key role in transmission and persistence of these important zoonotic agents; however, little is known about the molecular mechanisms that allow for bacterial survival within this harsh environment. Recently, a highly virulent C. jejuni sheep abortion (SA) clone represented by the clinical isolate IA3902 has emerged as the dominant cause for sheep abortion in the United States. Previous studies have indicated that the C. jejuni clone SA can frequently be isolated from the gallbladders of otherwise healthy sheep, suggesting that the gallbladder may serve as an important reservoir for infection. To begin to understand the molecular mechanisms associated with survival in the host gallbladder, C. jejuni IA3902 was exposed for up to 24 h to both the natural ovine host in vivo gallbladder environment, as well as ovine bile in vitro. Following exposure, total RNA was isolated from the bile and high throughput deep sequencing of strand specific rRNA-depleted total RNA was used to characterize the transcriptome of IA3902 under these conditions. Our results demonstrated for the first time the complete transcriptome of C. jejuni IA3902 during exposure to an important host environment, the sheep gallbladder. Exposure to the host environment as compared to in vitro bile alone provided a more robust picture of the complexity of gene regulation required for survival in the host gallbladder. A subset of genes including a large number of protein coding genes as well as seven previously identified non-coding RNAs were confirmed to be differentially expressed within our data, suggesting that they may play a key role in adaptation upon exposure to these conditions. This research provides valuable insights into the molecular mechanisms that may be utilized by C. jejuni IA3902 to colonize and survive within the inhospitable gallbladder environment.
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Affiliation(s)
- Amanda J Kreuder
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State UniversityAmes, IA, United States.,Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State UniversityAmes, IA, United States
| | - Jennifer A Schleining
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State UniversityAmes, IA, United States
| | - Michael Yaeger
- Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State UniversityAmes, IA, United States
| | - Qijing Zhang
- Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State UniversityAmes, IA, United States
| | - Paul J Plummer
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State UniversityAmes, IA, United States.,Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State UniversityAmes, IA, United States
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9
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Yasuike M, Nishiki I, Iwasaki Y, Nakamura Y, Fujiwara A, Shimahara Y, Kamaishi T, Yoshida T, Nagai S, Kobayashi T, Katoh M. Analysis of the complete genome sequence of Nocardia seriolae UTF1, the causative agent of fish nocardiosis: The first reference genome sequence of the fish pathogenic Nocardia species. PLoS One 2017; 12:e0173198. [PMID: 28257489 PMCID: PMC5336288 DOI: 10.1371/journal.pone.0173198] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 02/16/2017] [Indexed: 01/15/2023] Open
Abstract
Nocardiosis caused by Nocardia seriolae is one of the major threats in the aquaculture of Seriola species (yellowtail; S. quinqueradiata, amberjack; S. dumerili and kingfish; S. lalandi) in Japan. Here, we report the complete nucleotide genome sequence of N. seriolae UTF1, isolated from a cultured yellowtail. The genome is a circular chromosome of 8,121,733 bp with a G+C content of 68.1% that encodes 7,697 predicted proteins. In the N. seriolae UTF1 predicted genes, we found orthologs of virulence factors of pathogenic mycobacteria and human clinical Nocardia isolates involved in host cell invasion, modulation of phagocyte function and survival inside the macrophages. The virulence factor candidates provide an essential basis for understanding their pathogenic mechanisms at the molecular level by the fish nocardiosis research community in future studies. We also found many potential antibiotic resistance genes on the N. seriolae UTF1 chromosome. Comparative analysis with the four existing complete genomes, N. farcinica IFM 10152, N. brasiliensis HUJEG-1 and N. cyriacigeorgica GUH-2 and N. nova SH22a, revealed that 2,745 orthologous genes were present in all five Nocardia genomes (core genes) and 1,982 genes were unique to N. seriolae UTF1. In particular, the N. seriolae UTF1 genome contains a greater number of mobile elements and genes of unknown function that comprise the differences in structure and gene content from the other Nocardia genomes. In addition, a lot of the N. seriolae UTF1-specific genes were assigned to the ABC transport system. Because of limited resources in ocean environments, these N. seriolae UTF1 specific ABC transporters might facilitate adaptation strategies essential for marine environment survival. Thus, the availability of the complete N. seriolae UTF1 genome sequence will provide a valuable resource for comparative genomic studies of N. seriolae isolates, as well as provide new insights into the ecological and functional diversity of the genus Nocardia.
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Affiliation(s)
- Motoshige Yasuike
- Research Center for Bioinformatics and Biosciences, National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Yokohama, Kanagawa, Japan
- * E-mail: (AF); (MY)
| | - Issei Nishiki
- Research Center for Bioinformatics and Biosciences, National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Yokohama, Kanagawa, Japan
| | - Yuki Iwasaki
- Research Center for Bioinformatics and Biosciences, National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Yokohama, Kanagawa, Japan
| | - Yoji Nakamura
- Research Center for Bioinformatics and Biosciences, National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Yokohama, Kanagawa, Japan
| | - Atushi Fujiwara
- Research Center for Bioinformatics and Biosciences, National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Yokohama, Kanagawa, Japan
- * E-mail: (AF); (MY)
| | - Yoshiko Shimahara
- Research Center of Fish Diseases, National Research Institute of Aquaculture, Japan Fisheries Research and Education Agency, Saiki, Oita, Japan
| | - Takashi Kamaishi
- Fisheries Agency, Ministry of Agriculture, Forestry and Fisheries, Chiyoda-ku, Tokyo, Japan
| | | | - Satoshi Nagai
- Research Center for Bioinformatics and Biosciences, National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Yokohama, Kanagawa, Japan
| | - Takanori Kobayashi
- Headquarters, Japan Fisheries Research and Education Agency, Yokohama, Kanagawa, Japan
| | - Masaya Katoh
- Research Center for Bioinformatics and Biosciences, National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Yokohama, Kanagawa, Japan
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10
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Javadi MB, Katzenmeier G. The Forgotten Virulence Factor: The 'non-conventional' Hemolysin TlyA And Its Role in Helicobacter pylori Infection. Curr Microbiol 2016; 73:930-937. [PMID: 27686341 DOI: 10.1007/s00284-016-1141-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 09/19/2016] [Indexed: 12/15/2022]
Abstract
Helicobacter pylori is a human-specific Gram-negative pathogenic bacterium which colonizes the gastric mucosal layer in the stomach causing diseases such as peptic ulcer, adenocarcinoma, and gastric lymphoma. It is estimated that approximately half of the world's population is infected with H. pylori making it the most intensively characterized microbial pathogen up to now. Hemolysis has been suggested to significantly contribute to colonization of the stomach and disease progression by H. pylori. In a number of earlier studies, TlyA was characterized as a putative pore-forming cytolysin. Although a few observations in the literature suggest a role for TlyA as significant virulence factor of H. pylori, the molecular and structural characterization of this protein is much curtailed at present. Given the intensive characterization of numerous H. pylori virulence factors over the past decade, surprisingly little information exists for the TlyA toxin and its significance for pathogenesis. This review provides a brief overview on microbial hemolysis and its role for pathogenesis and discusses recent research efforts aimed at an improved understanding of the role of the 'non-conventional' hemolysin and its associated RNA methyltransferase TlyA from H. pylori.
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Affiliation(s)
- Mohammad Bagher Javadi
- Bacterial Toxin Research Cluster, Institute of Molecular Biosciences, Mahidol University, Nakornpathom, 73170, Thailand
| | - Gerd Katzenmeier
- Bacterial Toxin Research Cluster, Institute of Molecular Biosciences, Mahidol University, Nakornpathom, 73170, Thailand.
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11
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Kumar S, Mittal E, Deore S, Kumar A, Rahman A, Krishnasastry MV. Mycobacterial tlyA gene product is localized to the cell-wall without signal sequence. Front Cell Infect Microbiol 2015; 5:60. [PMID: 26347855 PMCID: PMC4543871 DOI: 10.3389/fcimb.2015.00060] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 07/31/2015] [Indexed: 01/09/2023] Open
Abstract
The mycobacterial tlyA gene product, Rv1694 (MtbTlyA), has been annotated as “hemolysin” which was re-annotated as 2′-O rRNA methyl transferase. In order to function as a hemolysin, it must reach the extracellular milieu with the help of signal sequence(s) and/or transmembrane segment(s). However, the MtbTlyA neither has classical signals sequences that signify general/Sec/Tat pathways nor transmembrane segments. Interestingly, the tlyA gene appears to be restricted to pathogenic strains such as H37Rv, M. marinum, M. leprae, than M. smegmatis, M. vaccae, M. kansasii etc., which highlights the need for a detailed investigation to understand its functions. In this study, we have provided several evidences which highlight the presence of TlyA on the surface of M. marinum (native host) and upon expression in M. smegmatis (surrogate host) and E. coli (heterologous host). The TlyA was visualized at the bacterial-surface by confocal microscopy and accessible to Proteinase K. In addition, sub-cellular fractionation has revealed the presence of TlyA in the membrane fractions and this sequestration is not dependent on TatA, TatC or SecA2 pathways. As a consequence of expression, the recombinant bacteria exhibit distinct hemolysis. Interestingly, the MtbTlyA was also detected in both membrane vesicles secreted by M. smegmatis and outer membrane vesicles secreted by E. coli. Our experimental evidences unambiguously confirm that the mycobacterial TlyA can reach the extra cellular milieu without any signal sequence. Hence, the localization of TlyA class of proteins at the bacterial surface may highlight the existence of non-classical bacterial secretion mechanisms.
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Affiliation(s)
- Santosh Kumar
- Membrane Biology, National Centre for Cell Science, Savitribai Phule Pune University Pune, India
| | - Ekansh Mittal
- Membrane Biology, National Centre for Cell Science, Savitribai Phule Pune University Pune, India
| | - Sapna Deore
- Membrane Biology, National Centre for Cell Science, Savitribai Phule Pune University Pune, India
| | - Anil Kumar
- Membrane Biology, National Centre for Cell Science, Savitribai Phule Pune University Pune, India
| | - Aejazur Rahman
- Membrane Biology, National Centre for Cell Science, Savitribai Phule Pune University Pune, India
| | - Musti V Krishnasastry
- Membrane Biology, National Centre for Cell Science, Savitribai Phule Pune University Pune, India
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12
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Mittal E, Kumar S, Rahman A, Krishnasastry MV. Modulation of phagolysosome maturation by bacterial tlyA gene product. J Biosci 2015; 39:821-34. [PMID: 25431411 DOI: 10.1007/s12038-014-9472-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The pathogenic traits of TlyA proteins of Mycobacterium tuberculosis are not known. Expressions of TlyA in bacteria that do not express endogenous TlyA adhere better to RAW264.7 macrophages and get phagocytosed efficiently. The internalized bacteria avoid acidification to the extent of greater than 65 percent in the case of both TlyA-expressing E. coli and M. smegmatis. Consistent with this observation, we have observed decreased co-localizaton of Lysosomal Membrane Associated Protein-1 (approx. 35 percent), Early Endosomal Antigen-1 (approx. 34 percent), Rab5 (approx. 30 percent) and Rab7 (approx. 35 percent) and enhanced colocalizaton of Rab14 (approx. 80 percent) on both TlyA-expressing bacteria as well as on TlyA-coated latex beads. These results suggest that the mycobacterial TlyA, in general, can modulate phagolysosome maturation pathway immediately after entry into macrophages, while other important molecules may aid the bacterium for long-term, intracellular survival at later point of time.
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Affiliation(s)
- Ekansh Mittal
- National Centre for Cell Science, Ganeshkhind Road, Pune University Campus, Pune 411 007, India
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13
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Lata K, Chattopadhyay K. Helicobacter pylori TlyA Forms Amyloid-like Aggregates with Potent Cytotoxic Activity. Biochemistry 2015; 54:3649-59. [PMID: 26015064 DOI: 10.1021/acs.biochem.5b00423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Helicobacter pylori is a potent human gastric pathogen. It is known to be associated with several gastroenteric disorders, including gastritis, peptic ulcer, and gastric cancer. The H. pylori genome encodes a gene product TlyA that has been shown to display potent membrane damaging properties and cytotoxic activity. On the basis of such properties, TlyA is considered as a potential virulence factor of H. pylori. In this study, we show that the H. pylori TlyA protein has a strong propensity to convert into the amyloid-like aggregated assemblies, upon exposure to elevated temperatures. Even at the physiological temperature of 37 °C, TlyA shows a strong amyloidogenic property. TlyA aggregates that are generated upon exposure at temperatures of ≥37 °C show prominent binding to dyes like thioflavin T and Nile Red. Transmission electron microscopy also demonstrates the presence of typical amyloid-like fibrils in the TlyA aggregates generated at 37 °C. Conversion of TlyA into the amyloid-like aggregates is found to be associated with major alterations in the secondary and tertiary structural organization of the protein. Finally, our study shows that the preformed amyloid-like aggregates of TlyA are capable of exhibiting potent cytotoxic activities against human gastric adenocarcinoma cells. Altogether, such a propensity of H. pylori TlyA to convert into the amyloid-like aggregated assemblies with cytotoxic activity suggests potential implications for the virulence functionality of the protein.
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Affiliation(s)
- Kusum Lata
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S. A. S. Nagar, Manauli 140306, Punjab, India
| | - Kausik Chattopadhyay
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S. A. S. Nagar, Manauli 140306, Punjab, India
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14
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Matsubara K, Nakajima T, Moore JE, Millar BC, Murayama T, Matsuda M. Molecular analysis of the tlyA gene in Campylobacter lari. Folia Microbiol (Praha) 2015; 60:505-14. [PMID: 25906999 DOI: 10.1007/s12223-015-0389-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 03/31/2015] [Indexed: 10/23/2022]
Abstract
Full-length tlyA gene and its adjacent genetic loci from the urease-positive thermophilic Campylobacter (UPTC) CF89-12 [approximately 15,000 base pairs (bp) in length], as well as a reference strain Campylobacter lari RM2100 (approximately 9,000 bp), were analyzed. The possible open-reading frame of tlyA from UPTC CF89-12 was shown to have 720 bp with a calculated molecular mass of approximately 26.7 kDa. Using a primer pair designed in silico, a total of approximately 1.1 kbp consisting of putative promoter region, structural gene for tlyA, and its adjacent genetic loci were identified in all 17 C. lari isolates [n = 13 for UPTC; n = 4 for urease-negative (UN) C. lari]. Although sequence differences were demonstrated at approximately 20 loci within the 90 bp non-coding (NC) region, including the putative promoter structure candidates immediately upstream of the tlyA gene among the 18 isolates including C. lari RM2100, no sequence differences were identified within the NC region among the five UN C. lari isolates examined. A start codon ATG and a probable ribosome-binding site, AGGC(T)GG(A), for the tlyA gene were identified in all 18 isolates, including C. lari RM2100. The putative intrinsic ρ-independent transcriptional terminator structure candidate was also identified for the tlyA gene in both UPTC CF89-12 and C. lari RM2100. Additionally, the hemolysis assay was performed with some of the C. lari isolates. The tlyA gene nucleotide sequence data may possibly be useful for discrimination between UN C. lari and UPTC organisms, as well as for the differentiation among the four thermophilic Campylobacter species.
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Affiliation(s)
- Keiko Matsubara
- Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa, 920-1181, Japan
| | - Takuya Nakajima
- Laboratory of Molecular Biology, Graduate School of Environmental Health Sciences, Azabu University, Sagamihara, Kanagawa, 252-5201, Japan
| | - John E Moore
- Department of Bacteriology, Northern Ireland Public Health Laboratory, Belfast City Hospital, Belfast, BT9 7AD, UK.,School of Biomedical Sciences, University of Ulster, Coleraine, BT52 1SA, UK.,Centre for Infection and Immunity, Queen's University, Belfast, BT9 7AB, Northern Ireland, UK
| | - Beverley C Millar
- Department of Bacteriology, Northern Ireland Public Health Laboratory, Belfast City Hospital, Belfast, BT9 7AD, UK
| | - Tsugiya Murayama
- Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa, 920-1181, Japan
| | - Motoo Matsuda
- Laboratory of Molecular Biology, Graduate School of Environmental Health Sciences, Azabu University, Sagamihara, Kanagawa, 252-5201, Japan.
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15
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Rahman MA, Sobia P, Dwivedi VP, Bhawsar A, Singh DK, Sharma P, Moodley P, Van Kaer L, Bishai WR, Das G. Mycobacterium tuberculosis TlyA Protein Negatively Regulates T Helper (Th) 1 and Th17 Differentiation and Promotes Tuberculosis Pathogenesis. J Biol Chem 2015; 290:14407-17. [PMID: 25847237 PMCID: PMC4505508 DOI: 10.1074/jbc.m115.653600] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Indexed: 12/30/2022] Open
Abstract
Mycobacterium tuberculosis, the causative agent of tuberculosis, is an ancient pathogen and a major cause of death worldwide. Although various virulence factors of M. tuberculosis have been identified, its pathogenesis remains incompletely understood. TlyA is a virulence factor in several bacterial infections and is evolutionarily conserved in many Gram-positive bacteria, but its function in M. tuberculosis pathogenesis has not been elucidated. Here, we report that TlyA significantly contributes to the pathogenesis of M. tuberculosis. We show that a TlyA mutant M. tuberculosis strain induces increased IL-12 and reduced IL-1β and IL-10 cytokine responses, which sharply contrasts with the immune responses induced by wild type M. tuberculosis. Furthermore, compared with wild type M. tuberculosis, TlyA-deficient M. tuberculosis bacteria are more susceptible to autophagy in macrophages. Consequently, animals infected with the TlyA mutant M. tuberculosis organisms exhibited increased host-protective immune responses, reduced bacillary load, and increased survival compared with animals infected with wild type M. tuberculosis. Thus, M. tuberculosis employs TlyA as a host evasion factor, thereby contributing to its virulence.
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Affiliation(s)
- Md Aejazur Rahman
- From the School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban, 4001 South Africa
| | - Parveen Sobia
- From the School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban, 4001 South Africa
| | - Ved Prakash Dwivedi
- From the School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban, 4001 South Africa
| | - Aakansha Bhawsar
- the Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Dhiraj Kumar Singh
- the Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Pawan Sharma
- the North Eastern Region Biotechnology Programme Management Cell, Defense Colony, New Delhi, India
| | - Prashini Moodley
- From the School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban, 4001 South Africa
| | - Luc Van Kaer
- the Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - William R Bishai
- the Center for Tuberculosis Research, Department of Medicine, Division of Infectious Diseases, Johns Hopkins School of Medicine, Baltimore, Maryland 21231-1001, and
| | - Gobardhan Das
- From the School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban, 4001 South Africa, the Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
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16
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Thamphiwatana S, Gao W, Pornpattananangkul D, Zhang Q, Fu V, Li J, Li J, Obonyo M, Zhang L. Phospholipase A2-responsive antibiotic delivery via nanoparticle-stabilized liposomes for the treatment of bacterial infection. J Mater Chem B 2014; 2:8201-8207. [PMID: 25544886 PMCID: PMC4276341 DOI: 10.1039/c4tb01110d] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Adsorbing small charged nanoparticles onto liposome surfaces to stabilize them against fusion and payload leakage has resulted in a new class of liposomes capable of environment-responsive drug delivery. Herein, we engineered a liposome formulation with a lipid composition sensitive to bacterium-secreted phospholipase A2 (PLA2) and adsorbed chitosan-modified gold nanoparticles (AuChi) onto the liposome surface. The resulting AuChi-stabilized liposomes (AuChi-liposomes) showed prohibited fusion activity and negligible drug leakage. However, upon exposure to either purified PLA2 enzyme or PLA2 secreted by Helicobacter pylori (H. pylori) bacteria in culture, AuChi-liposomes rapidly released the encapsulated payloads and such responsive release was retarded by adding quinacrine dihydrochloride, a PLA2 inhibitor. When loaded with doxycycline, AuChi-liposomes effectively inhibited H. pylori growth. Overall, the AuChi-liposomes allowed for smart "on-demand" antibitoic delivery: the more enzymes or bacteria present at the infection site, the more drug will be released to treat the infection. Given the strong association of PLA2 with a diverse range of diseases, the present liposomal delivery technique holds broad application potential for tissue microenvironment-responsive drug delivery.
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Affiliation(s)
- Soracha Thamphiwatana
- Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, USA
- Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Weiwei Gao
- Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, USA
- Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Dissaya Pornpattananangkul
- Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, USA
- Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Qiangzhe Zhang
- Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Victoria Fu
- Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, USA
- Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Jiayang Li
- Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Jieming Li
- Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Marygorret Obonyo
- Department of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Liangfang Zhang
- Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, USA
- Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
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17
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Lata K, Chattopadhyay K. Helicobacter pylori TlyA agglutinates liposomes and induces fusion and permeabilization of the liposome membranes. Biochemistry 2014; 53:3553-63. [PMID: 24846696 DOI: 10.1021/bi500152n] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Helicobacter pylori TlyA is a pore-forming hemolysin with potent cytotoxic activity. To explore the potential membrane-damaging activity of H. pylori TlyA, we have studied its interaction with the synthetic liposome vesicles. In our study, H. pylori TlyA shows a prominent ability to associate with the liposome vesicles without displaying an obligatory requirement for any protein receptor on the liposome membranes. Interaction of TlyA triggers agglutination of the liposome vesicles. Such agglutinating activity of TlyA could also be observed with erythrocytes before the induction of its pore-forming hemolytic activity. In addition to its agglutinating activity against liposomes, TlyA also induces fusion and disruption of the liposome membranes. Altogether, our study highlights novel membrane-damaging properties of H. pylori TlyA that have not been documented previously with any other TlyA family protein.
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Affiliation(s)
- Kusum Lata
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali , Sector 81, SAS Nagar, Manauli 140306, Punjab, India
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18
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The Cj0588 protein is a Campylobacter jejuni RNA methyltransferase. Biochem Biophys Res Commun 2014; 448:298-302. [PMID: 24796671 DOI: 10.1016/j.bbrc.2014.04.104] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 04/22/2014] [Indexed: 11/23/2022]
Abstract
TlyA proteins belong to 2'-O-methyltransferases. Methylation is a common posttranscriptional RNA modification. The Campylobacter jejuni Cj0588 protein belongs to the TlyA(I) protein family and is a rRNA methyltransferase. Methylation of ribosomal RNA catalyzed by Cj0588 appears to have an impact on the biology of the cell. Presence of the cj0588 gene in bacteria appears to be important for ribosome stability and virulence properties. Absence of the Cj0588 protein causes accumulation of the 50S ribosomal subunits, reduction in the amount of functional 70S ribosomes and confers increase resistance to capreomycin.
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19
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Lata K, Paul K, Chattopadhyay K. Functional characterization of Helicobacter pylori TlyA: pore-forming hemolytic activity and cytotoxic property of the protein. Biochem Biophys Res Commun 2014; 444:153-7. [PMID: 24434145 DOI: 10.1016/j.bbrc.2014.01.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 01/08/2014] [Indexed: 01/28/2023]
Abstract
Helicobacter pylori is a human specific gastric pathogen. H. pylori pathogenesis process involves a number of well-studied virulence factors that include the 'vacuolating cytotoxin' and the 'cytotoxin associated gene A'. Analysis of the H. pylori genome, however, indicates presence of additional virulence factors that are yet to be characterized in molecular detail. For example, H. pylori genome harbors a gene that has potential to encode a protein with sequence similarity to those of the TlyA-like proteins of several pathogenic bacteria. Earlier studies have indicated potential association of this H. pylori tlyA gene in the virulence mechanism of the organism. Despite such notions, however, the TlyA-like protein of H. pylori has not been studied previously in molecular detail. In particular, purified form of H. pylori TlyA has never been studied before toward exploring its functional properties. Here, we report characterization of the H. pylori TlyA protein purified from the recombinant over-expression system in Escherichia coli. Purified form of the recombinant TlyA exhibits prominent hemolytic activity against human erythrocytes, presumably via formation of pores of specific diameter in the cell membrane. Purified TlyA also triggers prominent cytotoxic responses in human gastric adenocarcinoma cells. Altogether, our study establishes H. pylori TlyA as a potential virulence factor of the organism.
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Affiliation(s)
- Kusum Lata
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Manauli, 140306 Punjab, India
| | - Karan Paul
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Manauli, 140306 Punjab, India
| | - Kausik Chattopadhyay
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Manauli, 140306 Punjab, India.
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20
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Los FCO, Randis TM, Aroian RV, Ratner AJ. Role of pore-forming toxins in bacterial infectious diseases. Microbiol Mol Biol Rev 2013; 77:173-207. [PMID: 23699254 PMCID: PMC3668673 DOI: 10.1128/mmbr.00052-12] [Citation(s) in RCA: 293] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pore-forming toxins (PFTs) are the most common bacterial cytotoxic proteins and are required for virulence in a large number of important pathogens, including Streptococcus pneumoniae, group A and B streptococci, Staphylococcus aureus, Escherichia coli, and Mycobacterium tuberculosis. PFTs generally disrupt host cell membranes, but they can have additional effects independent of pore formation. Substantial effort has been devoted to understanding the molecular mechanisms underlying the functions of certain model PFTs. Likewise, specific host pathways mediating survival and immune responses in the face of toxin-mediated cellular damage have been delineated. However, less is known about the overall functions of PFTs during infection in vivo. This review focuses on common themes in the area of PFT biology, with an emphasis on studies addressing the roles of PFTs in in vivo and ex vivo models of colonization or infection. Common functions of PFTs include disruption of epithelial barrier function and evasion of host immune responses, which contribute to bacterial growth and spreading. The widespread nature of PFTs make this group of toxins an attractive target for the development of new virulence-targeted therapies that may have broad activity against human pathogens.
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Affiliation(s)
| | - Tara M. Randis
- Department of Pediatrics, Columbia University, New York, New York, USA
| | - Raffi V. Aroian
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California, USA
| | - Adam J. Ratner
- Department of Pediatrics, Columbia University, New York, New York, USA
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21
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Monshupanee T. Increased Bacterial Hemolytic Activity is Conferred by Expression of TlyA Methyltransferase but not by its 2′-O-methylation of the Ribosome. Curr Microbiol 2013; 67:61-8. [DOI: 10.1007/s00284-013-0332-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 02/06/2013] [Indexed: 11/28/2022]
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22
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Rubinchik S, Seddon A, Karlyshev AV. Molecular mechanisms and biological role of Campylobacter jejuni attachment to host cells. Eur J Microbiol Immunol (Bp) 2012; 2:32-40. [PMID: 24611119 DOI: 10.1556/eujmi.2.2012.1.6] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 01/04/2012] [Indexed: 01/13/2023] Open
Abstract
Adhesion to host cells is an important step in pathogenesis of Campylobacter jejuni, which is the most prevalent bacterial cause of human gastroenteritis worldwide. In contrast to other bacteria such as E. coli and Salmonella, adherence of C. jejuni is not mediated by fimbria or pili. A number of C. jejuni adhesion-related factors have been described. However, the results obtained by different researchers in different laboratories are often contradictory and inconclusive, with only some of the factors described being confirmed as true adhesins. In this review, we present the current state of studies on the mechanisms of attachment of C. jejuni to host cells.
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Affiliation(s)
- S Rubinchik
- School of Life Sciences, Faculty of Science, Engineering and Computing, Kingston University Penrhyn Road, Kingston-upon Thames, KT1 2EE UK
| | - A Seddon
- School of Life Sciences, Faculty of Science, Engineering and Computing, Kingston University Penrhyn Road, Kingston-upon Thames, KT1 2EE UK
| | - A V Karlyshev
- School of Life Sciences, Faculty of Science, Engineering and Computing, Kingston University Penrhyn Road, Kingston-upon Thames, KT1 2EE UK
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23
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Cell-associated hemolysis induced by Helicobacter pylori is mediated by phospholipases with mitogen-activated protein kinase-activating properties. J Clin Microbiol 2012; 50:1014-8. [PMID: 22205825 DOI: 10.1128/jcm.05252-11] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Pathogenic Helicobacter pylori strains can selectively activate epithelial mitogen-activated protein kinase (MAPK) signaling pathways linked with disease. We now demonstrate that H. pylori-induced hemolysis is strain specific and is mediated by phospholipases PldA1 and PldD. Inactivation of PldD inhibited activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2), indicating that H. pylori hemolytic phospholipases also harbor MAPK-activating properties.
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Unique host iron utilization mechanisms of Helicobacter pylori revealed with iron-deficient chemically defined media. Infect Immun 2010; 78:1841-9. [PMID: 20176792 DOI: 10.1128/iai.01258-09] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Helicobacter pylori chronically infects the gastric mucosa, where it can be found free in mucus, attached to cells, and intracellularly. H. pylori requires iron for growth, but the sources of iron used in vivo are unclear. In previous studies, the inability to culture H. pylori without serum made it difficult to determine which host iron sources might be used by H. pylori. Using iron-deficient, chemically defined medium, we determined that H. pylori can bind and extract iron from hemoglobin, transferrin, and lactoferrin. H. pylori can use both bovine and human versions of both lactoferrin and transferrin, contrary to previous reports. Unlike other pathogens, H. pylori preferentially binds the iron-free forms of transferrin and lactoferrin, which limits its ability to extract iron from normal serum, which is not iron saturated. This novel strategy may have evolved to permit limited growth in host tissue during persistent colonization while excessive injury or iron depletion is prevented.
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Staphylococcus aureus fur regulates the expression of virulence factors that contribute to the pathogenesis of pneumonia. Infect Immun 2010; 78:1618-28. [PMID: 20100857 DOI: 10.1128/iai.01423-09] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The tremendous success of Staphylococcus aureus as a pathogen is due to the controlled expression of a diverse array of virulence factors. The effects of host environments on the expression of virulence factors and the mechanisms by which S. aureus adapts to colonize distinct host tissues are largely unknown. Vertebrates have evolved to sequester nutrient iron from invading bacteria, and iron availability is a signal that alerts pathogenic microorganisms when they enter the hostile host environment. Consistent with this, we report here that S. aureus senses alterations in the iron status via the ferric uptake regulator (Fur) and alters the abundance of a large number of virulence factors. These Fur-mediated changes protect S. aureus against killing by neutrophils, and Fur is required for full staphylococcal virulence in a murine model of infection. A potential mechanistic explanation for the impact of Fur on virulence is provided by the observation that Fur coordinates the reciprocal expression of cytolysins and a subset of immunomodulatory proteins. More specifically, S. aureus lacking fur exhibits decreased expression of immunomodulatory proteins and increased expression of cytolysins. These findings reveal that Fur is involved in initiating a regulatory program that organizes the expression of virulence factors during the pathogenesis of S. aureus pneumonia.
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Functional analysis of the Campylobacter jejuni cj0183 and cj0588 genes. Curr Microbiol 2008; 56:592-6. [PMID: 18389311 DOI: 10.1007/s00284-008-9130-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Accepted: 12/11/2007] [Indexed: 10/22/2022]
Abstract
The cj0183 and cj0588 genes identified in the Campylobacter jejuni NCTC 11168 genome encode proteins with amino acid sequences predicted to be homologous to other bacterial hemolysins. The Cj0183 protein exhibits homology to Brachyspira hyodysenteriae TlyC protein, whereas the cj0588 gene product is homologous to TlyA proteins Brachyspira hyodysenteriae, Helicobacter pylori, and Mycobacterium tuberculosis, which play a crucial role in bacterial virulence. The aim of our work was to examine the hemolytic activity and determine the role of cj0183- and cj0588-encoded proteins on the adherence of chosen C. jejuni strains to the Caco-2 cell line by constructing deletion mutants in the mentioned genes. We found out there is no difference in hemolytic activity between both mutants in gene cj0183 and cj0588 and the wild strains. However, Cj0588 protein but not Cj0183 is involved in adherence to the Caco-2 cells.
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Culture of Campylobacter jejuni with sodium deoxycholate induces virulence gene expression. J Bacteriol 2008; 190:2286-97. [PMID: 18223090 DOI: 10.1128/jb.01736-07] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Campylobacter jejuni, a spiral-shaped gram-negative bacterium, is a leading bacterial cause of human food-borne illness. Acute disease is associated with C. jejuni invasion of the intestinal epithelium. Further, maximal host cell invasion requires the secretion of proteins termed Campylobacter invasion antigens (Cia). As bile acids are known to alter the pathogenic behavior of other gastrointestinal pathogens, we hypothesized that the virulence potential of Campylobacter may be triggered by the bile acid deoxycholate (DOC). In support of this hypothesis, culturing C. jejuni with a physiologically relevant concentration of DOC significantly altered the kinetics of cell invasion, as shown by gentamicin protection assays. In contrast to C. jejuni harvested from Mueller-Hinton (MH) agar plates, C. jejuni harvested from MH agar plates supplemented with DOC secreted the Cia proteins, as judged by metabolic labeling experiments. DOC was also found to induce the expression of the ciaB gene, as determined by beta-galactosidase reporter, real-time reverse transcription-PCR, and microarray analyses. Microarray analysis further revealed that DOC induced the expression of virulence genes (ciaB, cmeABC, dccR, and tlyA). In summary, we demonstrated that it is possible to enhance the pathogenic behavior of C. jejuni by modifying the culture conditions. These results provide a foundation for identifying genes expressed by C. jejuni in response to in vivo-like culture conditions.
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MacCallum A, Hardy SP, Everest PH. Campylobacter jejuni inhibits the absorptive transport functions of Caco-2 cells and disrupts cellular tight junctions. MICROBIOLOGY-SGM 2005; 151:2451-2458. [PMID: 16000735 DOI: 10.1099/mic.0.27950-0] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Caco-2 cells are models of absorptive enterocytes. The net transport of fluid from apical to basolateral surfaces results in 'domes' forming in differentiated monolayers. Here, the effect of Campylobacter jejuni on this process has been examined. C. jejuni caused no changes in short-circuit current upon infection of Caco-2 cell monolayers in Ussing chambers. Thus, no active secretory events could be demonstrated using this model. It was therefore hypothesized that C. jejuni could inhibit the absorptive function of enterocytes and that this may contribute to diarrhoeal disease. C. jejuni infection of fluid-transporting ('doming') Caco-2 cells resulted in a significant reduction in dome number, which correlated with a decrease in tight junction integrity in infected monolayers, when measured as transepithelial electrical resistance. Defined mutants of C. jejuni also reduced dome numbers in infected monolayers. C. jejuni also altered the distribution of the tight junction protein occludin within cell monolayers. The addition to monolayers of extracellular gentamicin prevented these changes, indicating the contribution of extracellular bacteria to this process. Thus, tight junction integrity is required for fluid transport in Caco-2 cell monolayers as leaky tight junctions cannot maintain support of transported fluid at the basolateral surface of infected cell monolayers. Inhibition of absorptive cell function, changes in epithelial resistance and rearrangement of tight junctional proteins such as occludin represent a potential diarrhoeal mechanism of C. jejuni.
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Affiliation(s)
- Amanda MacCallum
- Institute of Comparative Medicine, University of Glasgow Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
| | - Simon P Hardy
- Department of Pharmacy and Biomolecular Sciences, University of Brighton, Lewes Road, Brighton BN2 4GJ, UK
| | - Paul H Everest
- Institute of Comparative Medicine, University of Glasgow Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
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MacCallum A, Haddock G, Everest PH. Campylobacter jejuni activates mitogen-activated protein kinases in Caco-2 cell monolayers and in vitro infected primary human colonic tissue. Microbiology (Reading) 2005; 151:2765-2772. [PMID: 16079352 DOI: 10.1099/mic.0.27979-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The mitogen-activated protein kinases (MAPKs) play a central role in many host signalling pathways. These signalling proteins are known to be involved in host responses against invasive bacteria including generation of chemotactic and inflammatory cytokines. It was hypothesized thatCampylobacter jejunimay activate MAPKs, as intestinal infection may induce a clinical and pathological picture of acute colonic inflammation. Infection of Caco-2 cell monolayers (human colonic epithelial cell line) and human colonic tissue withC. jejuni in vitrodemonstrated increased MAPK activity for ERK 1/2 (p44/42 MAPK), JNK and p38 MAPKs. Kinase activity and phosphorylated forms were increased in infected Caco-2 cells and human colonic explants, suggesting that these pathways are important in inflammatory responses induced byC. jejuniin man.
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Affiliation(s)
- Amanda MacCallum
- Institute of Comparative Medicine, Sir Henry Wellcome Building, University of Glasgow Faculty of Veterinary Medicine, Bearsden Road, Glasgow G61 1QH, UK
| | - Graham Haddock
- Department of Paediatric Surgery, Yorkhill Hospital, Glasgow G3 8SJ, UK
| | - Paul H Everest
- Institute of Comparative Medicine, Sir Henry Wellcome Building, University of Glasgow Faculty of Veterinary Medicine, Bearsden Road, Glasgow G61 1QH, UK
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Eppinger M, Baar C, Raddatz G, Huson DH, Schuster SC. Comparative analysis of four Campylobacterales. Nat Rev Microbiol 2004; 2:872-85. [PMID: 15494744 DOI: 10.1038/nrmicro1024] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Comparative genome analysis can be used to identify species-specific genes and gene clusters, and analysis of these genes can give an insight into the mechanisms involved in a specific bacteria-host interaction. Comparative analysis can also provide important information on the genome dynamics and degree of recombination in a particular species. This article describes the comparative genome analysis of representatives of four different Campylobacterales species - two pathogens of humans, Helicobacter pylori and Campylobacter jejuni, as well as Helicobacter hepaticus, which is associated with liver cancer in rodents, and the non-pathogenic commensal species, Wolinella succinogenes.
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Affiliation(s)
- Mark Eppinger
- Max-Planck-Institute for Developmental Biology, Genome Centre, Spemannstr. 35, 72076 Tübingen, Germany
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Lee JY, Cho PY, Kim TY, Kang SY, Song KY, Hong SJ. Hemolytic activity and developmental expression of pore-forming peptide, clonorin. Biochem Biophys Res Commun 2002; 296:1238-44. [PMID: 12207906 DOI: 10.1016/s0006-291x(02)02062-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Peptides pore-forming in cell membrane have been identified from a wide range of animals. A putative pore-forming peptide deduced from a cDNA clone of Clonorchis sinensis (clonorin) was predicted to consist of four amphipathic alpha-helices. Clonorin contained six invariably conserved cysteine residues, identified to form three disulfide bonds. These predicted structural features are highly homologous with pore-forming peptides, the amoebapores. Recombinant clonorin showed hemolytic activity toward rabbit erythrocytes. The hemolytic activity of C. sinensis extract increased dose-dependently and was inhibited by anti-clonorin immune sera. The clonorin was expressed developmentally in juvenile and adult flukes and localized in the intestinal epithelium of adult flukes. It is proposed that, through lysing host cellular components, clonorin could enhance proteolytic digestion in the intestine of C. sinensis.
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Affiliation(s)
- Ji-Yun Lee
- Department of Parasitology, Chung-Ang University College of Medicine, Tongjak-gu, 156-756, Seoul, Republic of Korea
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McCluskey J, Hannigan J, Harris JD, Wren B, Smith DGE. LsaA, an antigen involved in cell attachment and invasion, is expressed by Lawsonia intracellularis during infection in vitro and in vivo. Infect Immun 2002; 70:2899-907. [PMID: 12010978 PMCID: PMC128020 DOI: 10.1128/iai.70.6.2899-2907.2002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Lawsonia intracellularis has been identified recently as the etiological agent of proliferative enteropathies, which are characterized by intestinal epithelial hyperplasia and associated moderate immune responses. This disease complex has been reported in a broad range of animals, prevalently in pigs, and L. intracellularis has been linked with ulcerative colitis in humans. L. intracellularis is an obligate intracellular bacterium, and the pathogenic mechanisms used to cause disease are unknown. Using in vitro-grown organisms as a source of genomic DNA, we identified a Lawsonia gene which encodes a surface antigen, LsaA (for Lawsonia surface antigen), associated with attachment to and entry into cells. The deduced amino acid sequence of this protein showed some similarity to members of a novel protein family identified in a number of other bacterial pathogens but for which roles are not fully defined. Transcription of this gene was detected by reverse transcription-PCR in L. intracellularis grown in vitro in IEC18 cells and in bacteria present in ileal tissue from infected animals. Immunohistochemistry with specific monoclonal antibody and immunoblotting with sera from infected animals demonstrated that LsaA protein is synthesized by L. intracellularis during infection. Expression of this gene during infection in vitro and in vivo suggests that this surface antigen is involved during infection, and phenotypic analysis indicated a role during L. intracellularis attachment to and entry into intestinal epithelial cells
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Affiliation(s)
- Jackie McCluskey
- Zoonotic & Animal Pathogens Research Laboratory, Department of Medical Microbiology, Easter Bush Veterinary Centre, University of Edinburgh, Edinburgh, United Kingdom
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Abstract
Helicobacter pylori is known to be the cause of most gastric diseases, including both peptic ulcer disease and gastric cancer. In the absence of eradication, infection tends to be lifelong and the immune response ineffective in clearing the bacteria. A number of groups have investigated whether the immune clearance of infection can be achieved through a vaccination strategy, but to date, the results have been inconclusive. In fact, in most cases of natural infection, the host immune response leads to a chronic inflammation within the gastric mucosa that actually promotes the development of atrophy and neoplasia. In most cases, eradication of the organism leads to resolution of inflammation, which in many instances can result in reduction in atrophy and gastric cancer risk. This finding suggests that even at late stages, cancer progression is dependent, to a large extent, on infection/immune response. Work from a number of laboratories has led to the hypothesis that T-cells and the Th1 immune response, governed largely by host genetic factors, are strongly associated with the H. pylori-mediated induction of atrophy and cancer. Interleukin-1beta appears to be a particularly important cytokine that inhibits acid secretion and increases serum gastrin levels, factors strongly associated with cancer induction. The induction by H. pylori of cytokines and chemokines and growth-related genes is mediated by the MAPK and NF-kappaB signaling pathway. Recent studies have shown that NF-kappaB is activated through a NF-kappaB-inducing kinase/p21-activated kinase 1 pathway. H. pylori can also promote cellular apoptosis through a number of mechanisms, the most important of which is upregulation of the Fas/FasL pathway. Finally, understanding of H. pylori pathogenesis has been broadened and deepened by the application of genomics and proteomics to the organism.
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Affiliation(s)
- James G Fox
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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