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Han H, Zhang Y, Tang H, Zhou T, Khan A. A Review of the Use of Native and Engineered Probiotics for Colorectal Cancer Therapy. Int J Mol Sci 2024; 25:3896. [PMID: 38612706 PMCID: PMC11011422 DOI: 10.3390/ijms25073896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 03/22/2024] [Accepted: 03/28/2024] [Indexed: 04/14/2024] Open
Abstract
Colorectal cancer (CRC) is a serious global health concern, and researchers have been investigating different strategies to prevent, treat, or support conventional therapies for CRC. This review article comprehensively covers CRC therapy involving wild-type bacteria, including probiotics and oncolytic bacteria as well as genetically modified bacteria. Given the close relationship between CRC and the gut microbiota, it is crucial to compile and present a comprehensive overview of bacterial therapies used in the context of colorectal cancer. It is evident that the use of native and engineered probiotics for colorectal cancer therapy necessitates research focused on enhancing the therapeutic properties of probiotic strains.. Genetically engineered probiotics might be designed to produce particular molecules or to target cancer cells more effectively and cure CRC patients.
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Affiliation(s)
- Huawen Han
- State Key Laboratory of Grassland Agro-Ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Yifan Zhang
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK;
| | - Haibo Tang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou 730000, China; (H.T.); (T.Z.)
| | - Tuoyu Zhou
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou 730000, China; (H.T.); (T.Z.)
| | - Aman Khan
- College of Life Sciences, Northeast Forestry University, Harbin 150040, China
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2
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Lu Y, Mei N, Ying Y, Wang D, Li X, Zhao Y, Zhu Y, Shen S, Yin B. Bacteria-Based Nanoprobes for Cancer Therapy. Int J Nanomedicine 2024; 19:759-785. [PMID: 38283198 PMCID: PMC10821665 DOI: 10.2147/ijn.s438164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 01/04/2024] [Indexed: 01/30/2024] Open
Abstract
Surgical removal together with chemotherapy and radiotherapy has used to be the pillars of cancer treatment. Although these traditional methods are still considered as the first-line or standard treatments, non-operative situation, systemic toxicity or resistance severely weakened the therapeutic effect. More recently, synthetic biological nanocarriers elicited substantial interest and exhibited promising potential for combating cancer. In particular, bacteria and their derivatives are omnipotent to realize intrinsic tumor targeting and inhibit tumor growth with anti-cancer agents secreted and immune response. They are frequently employed in synergistic bacteria-mediated anticancer treatments to strengthen the effectiveness of anti-cancer treatment. In this review, we elaborate on the development, mechanism and advantage of bacterial therapy against cancer and then systematically introduce the bacteria-based nanoprobes against cancer and the recent achievements in synergistic treatment strategies and clinical trials. We also discuss the advantages as well as the limitations of these bacteria-based nanoprobes, especially the questions that hinder their application in human, exhibiting this novel anti-cancer endeavor comprehensively.
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Affiliation(s)
- Yiping Lu
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China
| | - Nan Mei
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China
| | - Yinwei Ying
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China
| | - Dongdong Wang
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China
| | - Xuanxuan Li
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China
| | - Yajing Zhao
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China
| | - Yuqi Zhu
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China
| | - Shun Shen
- Pharmacy Department, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, People’s Republic of China
- Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, People’s Republic of China
| | - Bo Yin
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China
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3
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Zhang Y, Huang R, Jiang Y, Shen W, Pei H, Wang G, Pei P, Yang K. The role of bacteria and its derived biomaterials in cancer radiotherapy. Acta Pharm Sin B 2023; 13:4149-4171. [PMID: 37799393 PMCID: PMC10547917 DOI: 10.1016/j.apsb.2022.10.013] [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: 06/14/2022] [Revised: 08/02/2022] [Accepted: 08/16/2022] [Indexed: 11/21/2022] Open
Abstract
Bacteria-mediated anti-tumor therapy has received widespread attention due to its natural tumor-targeting ability and specific immune-activation characteristics. It has made significant progress in breaking the limitations of monotherapy and effectively eradicating tumors, especially when combined with traditional therapy, such as radiotherapy. According to their different biological characteristics, bacteria and their derivatives can not only improve the sensitivity of tumor radiotherapy but also protect normal tissues. Moreover, genetically engineered bacteria and bacteria-based biomaterials have further expanded the scope of their applications in radiotherapy. In this review, we have summarized relevant researches on the application of bacteria and its derivatives in radiotherapy in recent years, expounding that the bacteria, bacterial derivatives and bacteria-based biomaterials can not only directly enhance radiotherapy but also improve the anti-tumor effect by improving the tumor microenvironment (TME) and immune effects. Furthermore, some probiotics can also protect normal tissues and organs such as intestines from radiation via anti-inflammatory, anti-oxidation and apoptosis inhibition. In conclusion, the prospect of bacteria in radiotherapy will be very extensive, but its biological safety and mechanism need to be further evaluated and studied.
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Affiliation(s)
- Yu Zhang
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection & School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China
| | - Ruizhe Huang
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection & School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China
| | - Yunchun Jiang
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection & School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China
| | - Wenhao Shen
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection & School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China
| | - Hailong Pei
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection & School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China
| | - Guanglin Wang
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection & School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China
| | - Pei Pei
- Teaching and Research Section of Nuclear Medicine, School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China
| | - Kai Yang
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection & School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China
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4
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Kompes G, Duvnjak S, Reil I, Hendriksen RS, Sørensen LH, Zdelar-Tuk M, Habrun B, Cvetnić L, Bagarić A, Špičić S. First Report and Characterization of the mcr-1 Positive Multidrug-Resistant Escherichia coli Strain Isolated from Pigs in Croatia. Microorganisms 2023; 11:2442. [PMID: 37894098 PMCID: PMC10609023 DOI: 10.3390/microorganisms11102442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/21/2023] [Accepted: 09/26/2023] [Indexed: 10/29/2023] Open
Abstract
The emergence and rapid spread of the plasmid-mediated colistin-resistant mcr-1 gene introduced a serious threat to public health. In 2021, a multi-drug resistant, mcr-1 positive Escherichia coli EC1945 strain, was isolated from pig caecal content in Croatia. Antimicrobial susceptibility testing and whole genome sequencing were performed. Bioinformatics tools were used to determine the presence of resistance genes, plasmid Inc groups, serotype, sequence type, virulence factors, and plasmid reconstruction. The isolated strain showed phenotypic and genotypic resistance to nine antimicrobial classes. It was resistant to colistin, gentamicin, ampicillin, cefepime, cefotaxime, ceftazidime, sulfamethoxazole, chloramphenicol, nalidixic acid, and ciprofloxacin. Antimicrobial resistance genes included mcr-1, blaTEM-1B, blaCTX-M-1, aac(3)-IId, aph(3')-Ia, aadA5, sul2, catA1, gyrA (S83L, D87N), and parC (A56T, S80I). The mcr-1 gene was located within the conjugative IncX4 plasmid. IncI1, IncFIB, and IncFII plasmids were also detected. The isolate also harbored 14 virulence genes and was classified as ST744 and O101:H10. ST744 is a member of the ST10 group which includes commensal, extraintestinal pathogenic E. coli isolates that play a crucial role as a reservoir of genes. Further efforts are needed to identify mcr-1-carrying E. coli isolates in Croatia, especially in food-producing animals to identify such gene reservoirs.
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Affiliation(s)
- Gordan Kompes
- Department for Bacteriology and Parasitology, Croatian Veterinary Institute, 10000 Zagreb, Croatia; (G.K.); (M.Z.-T.); (B.H.); (L.C.); (A.B.); (S.Š.)
| | - Sanja Duvnjak
- Department for Bacteriology and Parasitology, Croatian Veterinary Institute, 10000 Zagreb, Croatia; (G.K.); (M.Z.-T.); (B.H.); (L.C.); (A.B.); (S.Š.)
| | - Irena Reil
- Department for Bacteriology and Parasitology, Croatian Veterinary Institute, 10000 Zagreb, Croatia; (G.K.); (M.Z.-T.); (B.H.); (L.C.); (A.B.); (S.Š.)
| | - Rene S. Hendriksen
- Research Group for Global Capacity Building, National Food Institute, Technical University of Denmark, Kemitorvet, 2800 Lyngby, Denmark; (R.S.H.); (L.H.S.)
| | - Lauge Holm Sørensen
- Research Group for Global Capacity Building, National Food Institute, Technical University of Denmark, Kemitorvet, 2800 Lyngby, Denmark; (R.S.H.); (L.H.S.)
| | - Maja Zdelar-Tuk
- Department for Bacteriology and Parasitology, Croatian Veterinary Institute, 10000 Zagreb, Croatia; (G.K.); (M.Z.-T.); (B.H.); (L.C.); (A.B.); (S.Š.)
| | - Boris Habrun
- Department for Bacteriology and Parasitology, Croatian Veterinary Institute, 10000 Zagreb, Croatia; (G.K.); (M.Z.-T.); (B.H.); (L.C.); (A.B.); (S.Š.)
| | - Luka Cvetnić
- Department for Bacteriology and Parasitology, Croatian Veterinary Institute, 10000 Zagreb, Croatia; (G.K.); (M.Z.-T.); (B.H.); (L.C.); (A.B.); (S.Š.)
| | - Antonela Bagarić
- Department for Bacteriology and Parasitology, Croatian Veterinary Institute, 10000 Zagreb, Croatia; (G.K.); (M.Z.-T.); (B.H.); (L.C.); (A.B.); (S.Š.)
| | - Silvio Špičić
- Department for Bacteriology and Parasitology, Croatian Veterinary Institute, 10000 Zagreb, Croatia; (G.K.); (M.Z.-T.); (B.H.); (L.C.); (A.B.); (S.Š.)
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Ur Rehman Safi A, Mansour Salih M, Rahman H, Khattak B, El Askary A, Hussain Khalifa E, Qasim M. Immunoaffinity-based mass spectrometric characterization of immunoreactive proteins of Salmonella Typhi. Saudi J Biol Sci 2022; 30:103502. [DOI: 10.1016/j.sjbs.2022.103502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/14/2022] [Accepted: 11/10/2022] [Indexed: 11/18/2022] Open
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6
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A Genomic Island of Vibrio cholerae Encodes a Three-Component Cytotoxin with Monomer and Protomer Forms Structurally Similar to Alpha-Pore-Forming Toxins. J Bacteriol 2022; 204:e0055521. [PMID: 35435721 DOI: 10.1128/jb.00555-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Alpha-pore-forming toxins (α-PFTs) are secreted by many species of bacteria, including Escherichia coli, Aeromonas hydrophila, and Bacillus thuringiensis, as part of their arsenal of virulence factors, and are often cytotoxic. In particular, for α-PFTs, the membrane-spanning channel they form is composed of hydrophobic α-helices. These toxins oligomerize at the surface of target cells and transition from a soluble to a protomer state in which they expose their hydrophobic regions and insert into the membrane to form a pore. The pores may be composed of homooligomers of one component or heterooligomers with two or three components, resulting in bi- or tripartite toxins. The multicomponent α-PFTs are often expressed from a single operon. Recently, motility-associated killing factor A (MakA), an α-PFT, was discovered in Vibrio cholerae. We report that makA is found on the V. cholerae GI-10 genomic island within an operon containing genes for two other potential α-PFTs, MakB and MakE. We determined the X-ray crystal structures for MakA, MakB, and MakE and demonstrated that all three are structurally related to the α-PFT family in the soluble state, and we modeled their protomer state based on the α-PFT AhlB from A. hydrophila. We found that MakA alone is cytotoxic at micromolar concentrations. However, combining MakA with MakB and MakE is cytotoxic at nanomolar concentrations, with specificity for J774 macrophage cells. Our data suggest that MakA, -B, and -E are α-PFTs that potentially act as a tripartite pore-forming toxin with specificity for phagocytic cells. IMPORTANCE The bacterium Vibrio cholerae causes gastrointestinal, wound, and skin infections. The motility-associated killing factor A (MakA) was recently shown to be cytotoxic against colon, prostate, and other cancer cells. However, at the outset of this study, the capacity of MakA to damage cells in combination with other Mak proteins encoded in the same operon had not been elucidated. We determined the structures of three Mak proteins and established that they are structurally related to the α-PFTs. Compared to MakA alone, the combination of all three toxins was more potent specifically in mouse macrophages. This study highlights the idea that the Mak toxins are selectively cytotoxic and thus may function as a tripartite toxin with cell type specificity.
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Ulhuq FR, Mariano G. Bacterial pore-forming toxins. MICROBIOLOGY (READING, ENGLAND) 2022; 168:001154. [PMID: 35333704 PMCID: PMC9558359 DOI: 10.1099/mic.0.001154] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 02/03/2022] [Indexed: 12/11/2022]
Abstract
Pore-forming toxins (PFTs) are widely distributed in both Gram-negative and Gram-positive bacteria. PFTs can act as virulence factors that bacteria utilise in dissemination and host colonisation or, alternatively, they can be employed to compete with rival microbes in polymicrobial niches. PFTs transition from a soluble form to become membrane-embedded by undergoing large conformational changes. Once inserted, they perforate the membrane, causing uncontrolled efflux of ions and/or nutrients and dissipating the protonmotive force (PMF). In some instances, target cells intoxicated by PFTs display additional effects as part of the cellular response to pore formation. Significant progress has been made in the mechanistic description of pore formation for the different PFTs families, but in several cases a complete understanding of pore structure remains lacking. PFTs have evolved recognition mechanisms to bind specific receptors that define their host tropism, although this can be remarkably diverse even within the same family. Here we summarise the salient features of PFTs and highlight where additional research is necessary to fully understand the mechanism of pore formation by members of this diverse group of protein toxins.
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Affiliation(s)
- Fatima R. Ulhuq
- Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Giuseppina Mariano
- Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
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Cytolysin A (ClyA): A Bacterial Virulence Factor with Potential Applications in Nanopore Technology, Vaccine Development, and Tumor Therapy. Toxins (Basel) 2022; 14:toxins14020078. [PMID: 35202106 PMCID: PMC8880466 DOI: 10.3390/toxins14020078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 12/26/2022] Open
Abstract
Cytolysin A (ClyA) is a pore-forming toxin that is produced by some bacteria from the Enterobacteriaceae family. This review provides an overview of the current state of knowledge regarding ClyA, including the prevalence of the encoding gene and its transcriptional regulation, the secretion pathway used by the protein, and the mechanism of protein assembly, and highlights potential applications of ClyA in biotechnology. ClyA expression is regulated at the transcriptional level, primarily in response to environmental stressors, and ClyA can exist stably both as a soluble monomer and as an oligomeric membrane complex. At high concentrations, ClyA induces cytolysis, whereas at low concentrations ClyA can affect intracellular signaling. ClyA is secreted in outer membrane vesicles (OMVs), which has important implications for biotechnology applications. For example, the native pore-forming ability of ClyA suggests that it could be used as a component of nanopore-based technologies, such as sequencing platforms. ClyA has also been exploited in vaccine development owing to its ability to present antigens on the OMV surface and provoke a robust immune response. In addition, ClyA alone or OMVs carrying ClyA fusion proteins have been investigated for their potential use as anti-tumor agents.
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Allemailem KS. Innovative Approaches of Engineering Tumor-Targeting Bacteria with Different Therapeutic Payloads to Fight Cancer: A Smart Strategy of Disease Management. Int J Nanomedicine 2021; 16:8159-8184. [PMID: 34938075 PMCID: PMC8687692 DOI: 10.2147/ijn.s338272] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 11/29/2021] [Indexed: 12/12/2022] Open
Abstract
Conventional therapies for cancer eradication like surgery, radiotherapy, and chemotherapy, even though most widely used, still suffer from some disappointing outcomes. The limitations of these therapies during cancer recurrence and metastasis demonstrate the need for better alternatives. Some bacteria preferentially colonize and proliferate inside tumor mass; thus these bacteria can be used as ideal candidates to deliver antitumor therapeutic agents. The bacteria like Bacillus spp., Clostridium spp., E. coli, Listeria spp., and Salmonella spp. can be reprogrammed to produce, transport, and deliver anticancer agents, eg, cytotoxic agents, prodrug converting enzymes, immunomodulators, tumor stroma targeting agents, siRNA, and drug-loaded nanoformulations based on clinical requirements. In addition, these bacteria can be genetically modified to express various functional proteins and targeting ligands that can enhance the targeting approach and controlled drug-delivery. Low tumor-targeting and weak penetration power deep inside the tumor mass limits the use of anticancer drug-nanoformulations. By using anticancer drug nanoformulations and other therapeutic payloads in combination with antitumor bacteria, it makes a synergistic effect against cancer by overcoming the individual limitations. The tumor-targeting bacteria can be either used as a monotherapy or in addition with other anticancer therapies like photothermal therapy, photodynamic therapy, and magnetic field therapy to accomplish better clinical outcomes. The toxicity issues on normal tissues is the main concern regarding the use of engineered antitumor bacteria, which requires deeper research. In this article, the mechanism by which bacteria sense tumor microenvironment, role of some anticancer agents, and the recent advancement of engineering bacteria with different therapeutic payloads to combat cancers has been reviewed. In addition, future prospective and some clinical trials are also discussed.
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Affiliation(s)
- Khaled S Allemailem
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia
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Zhu C, Ji Z, Ma J, Ding Z, Shen J, Wang Q. Recent Advances of Nanotechnology-Facilitated Bacteria-Based Drug and Gene Delivery Systems for Cancer Treatment. Pharmaceutics 2021; 13:940. [PMID: 34202452 PMCID: PMC8308943 DOI: 10.3390/pharmaceutics13070940] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/17/2021] [Accepted: 06/21/2021] [Indexed: 12/13/2022] Open
Abstract
Cancer is one of the most devastating and ubiquitous human diseases. Conventional therapies like chemotherapy and radiotherapy are the most widely used cancer treatments. Despite the notable therapeutic improvements that these measures achieve, disappointing therapeutic outcome and cancer reoccurrence commonly following these therapies demonstrate the need for better alternatives. Among them, bacterial therapy has proven to be effective in its intrinsic cancer targeting ability and various therapeutic mechanisms that can be further bolstered by nanotechnology. In this review, we will discuss recent advances of nanotechnology-facilitated bacteria-based drug and gene delivery systems in cancer treatment. Therapeutic mechanisms of these hybrid nanoformulations are highlighted to provide an up-to-date understanding of this emerging field.
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Affiliation(s)
- Chaojie Zhu
- Department of Cardiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China;
- Chu Kochen Honors College of Zhejiang University, Hangzhou 310058, China; (Z.J.); (J.M.)
- Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhiheng Ji
- Chu Kochen Honors College of Zhejiang University, Hangzhou 310058, China; (Z.J.); (J.M.)
- Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Junkai Ma
- Chu Kochen Honors College of Zhejiang University, Hangzhou 310058, China; (Z.J.); (J.M.)
- Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhijie Ding
- College of Letters & Science, University of California, Berkeley, CA 94704, USA;
| | - Jie Shen
- Department of Pharmacy, School of Medicine, Zhejiang University City College, Hangzhou 310015, China
| | - Qiwen Wang
- Department of Cardiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China;
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Chiang CJ, Huang PH. Metabolic engineering of probiotic Escherichia coli for cytolytic therapy of tumors. Sci Rep 2021; 11:5853. [PMID: 33712706 PMCID: PMC7971005 DOI: 10.1038/s41598-021-85372-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/28/2021] [Indexed: 12/13/2022] Open
Abstract
Bacterial cancer therapy was developed using probiotic Escherichia coli Nissle 1917 (EcN) for medical intervention of colorectal cancer. EcN was armed with HlyE, a small cytotoxic protein, under the control of the araBAD promoter (PBAD). The intrinsic limitation of PBAD for the gene expression is known to be negated by glucose and afflicted with all-or-nothing induction in host bacteria. This issue was addressed by metabolic engineering of EcN to uncouple the glucose-mediated control circuit and the L-arabinose transport-induction loop and to block L-arabinose catabolism. As a result, the reprogrammed strain (designated EcNe) enabled efficient expression of HlyE in a temporal control manner. The HlyE production was insensitive to glucose and reached a saturated level in response to L-arabinose at 30-50 μM. Moreover, the administrated EcNe exhibited tumor-specific colonization with the tumor-to-organ ratio of 106:1. Equipped with HlyE, EcNe significantly caused tumor regression in mice xenografted with human colorectal cancer cells. Overall, this study proposes a new strategy for the bacteria-mediated delivery of therapeutic proteins to tumors.
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Affiliation(s)
- Chung-Jen Chiang
- Department of Medical Laboratory Science and Biotechnology, China Medical University, No. 91, Hsueh-Shih Road, Taichung, 40402, Taiwan.
| | - Po-Han Huang
- Department of Medical Laboratory Science and Biotechnology, China Medical University, No. 91, Hsueh-Shih Road, Taichung, 40402, Taiwan
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Sathyanarayana P, Visweswariah SS, Ayappa KG. Mechanistic Insights into Pore Formation by an α-Pore Forming Toxin: Protein and Lipid Bilayer Interactions of Cytolysin A. Acc Chem Res 2021; 54:120-131. [PMID: 33291882 DOI: 10.1021/acs.accounts.0c00551] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Pore forming toxins (PFTs) are the largest class of bacterial toxins playing a central role in bacterial pathogenesis. They are proteins specifically designed to form nanochannels in the membranes of target cells, ultimately resulting in cell death and establishing infection. PFTs are broadly classified as α- and β-PFTs, depending on secondary structures that form the transmembrane channel. A unique feature about this class of proteins is the drastic conformational changes and complex oligomerization pathways that occur upon exposure to the plasma membrane. A molecular understanding of pore formation has implications in designing novel intervention strategies to combat rising antimicrobial resistance, targeted-cancer therapy, as well as designing nanopores for specialized technologies. Central to unraveling the pore formation pathway is the availability of high resolution crystal structures. In this regard, β-toxins are better understood, when compared with α-toxins whose pore forming mechanisms are complicated by an incomplete knowledge of the driving forces for amphiphatic membrane-inserted helices to organize into functional pores. With the publication of the first crystal structure for an α-toxin, cytolysin A (ClyA), in 2009 we embarked on an extensive multiscale study to unravel its pore forming mechanism. This Account represents the collective mechanistic knowledge gained in our laboratories using a variety of experimental and theoretical techniques which include large scale molecular dynamics (MD) simulations, kinetic modeling studies, single-molecule fluorescence imaging, and super-resolution spectroscopy. We reported MD simulations of the ClyA protomer, oligomeric intermediates, and full pore complex in a lipid bilayer and mapped the conformational transitions that accompany membrane binding. Using single-molecule fluorescence imaging, the conformational transition was experimentally verified by analysis of various diffusion states of membrane bound ClyA. Importantly, we have uncovered a hitherto unknown putative cholesterol binding motif in the membrane-inserted helix of ClyA. Distinct binding pockets for cholesterol formed by adjacent membrane-inserted helices are revealed in MD simulations. Cholesterol appears to play a dual role by stabilizing both the membrane-inserted protomer as well as oligomeric intermediates. Molecular dynamics simulations and kinetic modeling studies suggest that the membrane-inserted arcs oligomerize reversibly to form the predominant transmembrane oligomeric intermediates during pore formation. We posit that this mechanistic understanding of the complex action of α-PFTs has implications in unraveling pore assembly across the wider family of bacterial toxins. With emerging antimicrobial resistance, alternate therapies may rely on disrupting pore functionality or oligomerization of these pathogenic determinants utilized by bacteria, and our study includes assessing the potential for dendrimers as pore blockers.
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Affiliation(s)
- Pradeep Sathyanarayana
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, India 560012
| | - Sandhya S. Visweswariah
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, India 560012
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India 560012
| | - K. Ganapathy Ayappa
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, India 560012
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, India 560012
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13
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Insights on the genetic features of endometrial pathogenic Escherichia coli strains from pyometra in companion animals: Improving the knowledge about pathogenesis. INFECTION GENETICS AND EVOLUTION 2020; 85:104453. [DOI: 10.1016/j.meegid.2020.104453] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/11/2020] [Accepted: 06/30/2020] [Indexed: 12/18/2022]
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14
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Fuentes-Castillo D, Navas-Suárez PE, Gondim MF, Esposito F, Sacristán C, Fontana H, Fuga B, Piovani C, Kooij R, Lincopan N, Catão-Dias JL. Genomic characterization of multidrug-resistant ESBL-producing Escherichia coli ST58 causing fatal colibacillosis in critically endangered Brazilian merganser (Mergus octosetaceus). Transbound Emerg Dis 2020; 68:258-266. [PMID: 32544292 PMCID: PMC8246901 DOI: 10.1111/tbed.13686] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/03/2020] [Accepted: 06/08/2020] [Indexed: 12/12/2022]
Abstract
Even though antimicrobial‐resistant bacteria have begun to be detected in wildlife, raising important issues related to their transmission and persistence of clinically important pathogens in the environment, little is known about the role of these bacteria on wildlife health, especially on endangered species. The Brazilian merganser (Mergus octosetaceus) is one of the most threatened waterfowl in the world, classified as Critically Endangered by the International Union for Conservation of Nature. In 2019, a fatal case of sepsis was diagnosed in an 8‐day‐old Brazilian merganser inhabiting a zoological park. At necropsy, major gross lesions were pulmonary and hepatic congestion. Using microbiologic and genomic methods, we identified a multidrug‐resistant (MDR) extended‐spectrum β‐lactamase (ESBL) CTX‐M‐8‐producing Escherichia coli (designed as PMPU strain) belonging to the international clone ST58, in coelomic cavity, oesophagus, lungs, small intestine and cloaca samples. PMPU strain harboured a broad resistome against antibiotics (cephalosporins, tetracyclines, aminoglycosides, sulphonamides, trimethoprim and quinolones), domestic/hospital disinfectants and heavy metals (arsenic, mercury, lead, copper and silver). Additionally, the virulence of E. coli PMPU strain was confirmed using a wax moth (Galleria mellonella) infection model, and it was supported by the presence of virulence genes encoding toxins, adherence factors, invasins and iron acquisition systems. Broad resistome and virulome of PMPU contributed to therapeutic failure and death of the animal. In brief, we report for the first time a fatal colibacillosis by MDR ESBL‐producing E. coli in critically endangered Brazilian merganser, highlighting that besides colonization, critical priority pathogens are threatening wildlife. E. coli ST58 clone has been previously reported in humans, food‐producing animals, wildlife and environment, supporting broad adaptation and persistence at human–animal–environment interface.
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Affiliation(s)
- Danny Fuentes-Castillo
- Department of Pathology, School of Veterinary Medicine and Animal Sciences, University of São Paulo, São Paulo, Brazil.,One Health Brazilian Resistance Project (OneBR), São Paulo, Brazil
| | - Pedro Enrique Navas-Suárez
- Department of Pathology, School of Veterinary Medicine and Animal Sciences, University of São Paulo, São Paulo, Brazil
| | | | - Fernanda Esposito
- One Health Brazilian Resistance Project (OneBR), São Paulo, Brazil.,Department of Clinical Analysis, Faculty of Pharmacy, University of São Paulo, São Paulo, Brazil
| | - Carlos Sacristán
- Department of Pathology, School of Veterinary Medicine and Animal Sciences, University of São Paulo, São Paulo, Brazil
| | - Herrison Fontana
- One Health Brazilian Resistance Project (OneBR), São Paulo, Brazil.,Department of Clinical Analysis, Faculty of Pharmacy, University of São Paulo, São Paulo, Brazil
| | - Bruna Fuga
- One Health Brazilian Resistance Project (OneBR), São Paulo, Brazil.,Department of Clinical Analysis, Faculty of Pharmacy, University of São Paulo, São Paulo, Brazil.,Department of Microbiology, Instituto de Ciências Biomédicas, University of São Paulo, São Paulo, Brazil
| | | | | | - Nilton Lincopan
- One Health Brazilian Resistance Project (OneBR), São Paulo, Brazil.,Department of Clinical Analysis, Faculty of Pharmacy, University of São Paulo, São Paulo, Brazil.,Department of Microbiology, Instituto de Ciências Biomédicas, University of São Paulo, São Paulo, Brazil
| | - José Luiz Catão-Dias
- Department of Pathology, School of Veterinary Medicine and Animal Sciences, University of São Paulo, São Paulo, Brazil
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15
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Kalule JB, Fortuin S, Calder B, Robberts L, Keddy KH, Nel AJM, Garnett S, Nicol M, Warner DF, Soares NC, Blackburn JM. Proteomic comparison of three clinical diarrhoeagenic drug-resistant Escherichia coli isolates grown on CHROMagar™STEC media. J Proteomics 2017; 180:25-35. [PMID: 28887208 DOI: 10.1016/j.jprot.2017.09.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 08/21/2017] [Accepted: 09/02/2017] [Indexed: 02/06/2023]
Abstract
Shiga-toxin-producing Escherichia coli (STEC) and enteropathogenic Escherichia coli (EPEC) are key diarrhoea-causing foodborne pathogens. We used proteomics to characterize the virulence and antimicrobial resistance protein profiles of three clinical pathogenic E. coli isolates (two EPEC [one resistant to ciprofloxacin] and one STEC) cultured on CHROMagar™STEC solid media after minimal laboratory passage. We identified 4767 unique peptides from 1630 protein group across all three clinical E. coli strains. Label-free proteomic analysis allowed the identification of virulence and drug resistance proteins that were unique to each of the clinical isolates compared in this study. The B subunit of Shiga toxin, ToxB, was uniquely detected in the STEC strain while several other virulence factors including SheA, OmpF, OmpC and OmpX were significantly more abundant in the STEC strain. The ciprofloxacin resistant EPEC isolate possessed reduced levels of key virulence proteins compared to the ciprofloxacin susceptible EPEC and STEC strains. Parallel reaction monitoring assays validated the presence of biologically relevant proteins across biologically-replicated cultures. Propagation of clinical isolates on a relevant solid medium followed by mass spectrometry analysis represents a convenient means to quantify virulence factors and drug resistance determinants that might otherwise be lost through extensive in vitro passage in enteropathogenic bacteria. SIGNIFICANCE Through the use of quantitative proteomics, we have characterized the virulence and antimicrobial resistance attributes of three clinically isolated, pathogenic E. coli strains cultured on solid media. Our results provide new, quantitative data on the expressed proteomes of these tellurite-resistant, diarrhoeagenic E. coli strains and reveal a subset of antimicrobial resistance and virulence proteins that are differentially abundant between these clinical strains. Our quantitative proteomics-based approach should thus have applicability in microbiological diagnostic labs for the identification of pathogenic/drug resistant E. coli in the future.
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Affiliation(s)
- John Bosco Kalule
- Division of Medical Microbiology, Department of Pathology, University of Cape Town, South Africa
| | - Suereta Fortuin
- Division of Chemical & Systems Biology, Department of Integrative Biomedical Sciences, University of Cape Town, Cape Town, South Africa
| | - Bridget Calder
- Division of Chemical & Systems Biology, Department of Integrative Biomedical Sciences, University of Cape Town, Cape Town, South Africa
| | - Lourens Robberts
- Division of Medical Microbiology, Department of Pathology, University of Cape Town, South Africa
| | - Karen H Keddy
- Bacteriology Division, Centre for Enteric Diseases, National Institute for Communicable Diseases, Sandringham, Johannesburg, South Africa; Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Andrew J M Nel
- Division of Chemical & Systems Biology, Department of Integrative Biomedical Sciences, University of Cape Town, Cape Town, South Africa
| | - Shaun Garnett
- Division of Chemical & Systems Biology, Department of Integrative Biomedical Sciences, University of Cape Town, Cape Town, South Africa
| | - Mark Nicol
- Division of Medical Microbiology, Department of Pathology, University of Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, South Africa
| | - Digby F Warner
- Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, South Africa; MRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Division of Medical Microbiology, Department of Pathology, University of Cape Town, South Africa
| | - Nelson C Soares
- Division of Chemical & Systems Biology, Department of Integrative Biomedical Sciences, University of Cape Town, Cape Town, South Africa.
| | - Jonathan M Blackburn
- Division of Chemical & Systems Biology, Department of Integrative Biomedical Sciences, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, South Africa.
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16
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Liu X, Ding S, Shi P, Dietrich R, Märtlbauer E, Zhu K. Non-hemolytic enterotoxin of Bacillus cereus induces apoptosis in Vero cells. Cell Microbiol 2016; 19. [PMID: 27762484 DOI: 10.1111/cmi.12684] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 10/10/2016] [Accepted: 10/11/2016] [Indexed: 12/18/2022]
Abstract
Bacillus cereus is an opportunistic pathogen that often causes foodborne infectious diseases and food poisoning. Non-hemolytic enterotoxin (Nhe) is the major toxin found in almost all enteropathogenic B. cereus and B. thuringiensis isolates. However, little is known about the cellular response after Nhe triggered pore formation on cell membrane. Here, we demonstrate that Nhe induced cell cycle arrest at G0 /G1 phase and provoked apoptosis in Vero cells, most likely associated with mitogen-activated protein kinase (MAPK) and death receptor pathways. The influx of extracellular calcium ions and increased level of reactive oxygen species in cytoplasm were sensed by apoptosis signal-regulating kinase 1 (ASK1) and p38 MAPK. Extrinsic death receptor Fas could also promote the activation of p38 MAPK. Subsequently, ASK1 and p38 MAPK triggered downstream caspase-8 and 3 to initiate apoptosis. Our results clearly demonstrate that ASK1, and Fas-p38 MAPK-mediated caspase-8 dependent pathways are involved in apoptotic cell death provoked by the pore-forming enterotoxin Nhe.
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Affiliation(s)
- Xiaoye Liu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, China.,National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Shuangyang Ding
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Peijie Shi
- The Children's Hospital of Fudan University, Shanghai, China
| | - Richard Dietrich
- Institute of Food Safety, Department of Veterinary Sciences, Ludwig-Maximilians-University Munich, Oberschleißheim, Germany
| | - Erwin Märtlbauer
- Institute of Food Safety, Department of Veterinary Sciences, Ludwig-Maximilians-University Munich, Oberschleißheim, Germany
| | - Kui Zhu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, China
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17
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Generation of a naïve human single chain variable fragment (scFv) library for the identification of monoclonal scFv against Salmonella Typhi Hemolysin E antigen. Toxicon 2016; 117:94-101. [DOI: 10.1016/j.toxicon.2016.04.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 03/30/2016] [Accepted: 04/12/2016] [Indexed: 12/29/2022]
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18
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Campylobacter jejuni increases flagellar expression and adhesion of noninvasive Escherichia coli: effects on enterocytic Toll-like receptor 4 and CXCL-8 expression. Infect Immun 2015; 83:4571-81. [PMID: 26371123 DOI: 10.1128/iai.00970-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 09/04/2015] [Indexed: 12/17/2022] Open
Abstract
Campylobacter jejuni is the most common cause of bacterium-induced gastroenteritis, and while typically self-limiting, C. jejuni infections are associated with postinfectious intestinal disorders, including flares in patients with inflammatory bowel disease and postinfectious irritable bowel syndrome (PI-IBS), via mechanisms that remain obscure. Based on the hypothesis that acute campylobacteriosis may cause pathogenic microbiota dysbiosis, we investigated whether C. jejuni may activate dormant virulence genes in noninvasive Escherichia coli and examined the epithelial pathophysiological consequences of these alterations. Microarray and quantitative real-time PCR analyses revealed that E. coli adhesin, flagellum, and hemolysin gene expression were increased when E. coli was exposed to C. jejuni-conditioned medium. Increased development of bacterial flagella upon exposure to live C. jejuni or C. jejuni-conditioned medium was observed under transmission electron microscopy. Atomic force microscopy demonstrated that the forces of bacterial adhesion to colonic T84 enterocytes, and the work required to rupture this adhesion, were significantly increased in E. coli exposed to C. jejuni-conditioned media. Finally, C. jejuni-modified E. coli disrupted TLR4 gene expression and induced proinflammatory CXCL-8 gene expression in colonic enterocytes. Together, these data suggest that exposure to live C. jejuni, and/or to its secretory-excretory products, may activate latent virulence genes in noninvasive E. coli and that these alterations may directly trigger proinflammatory signaling in intestinal epithelia. These observations shed new light on mechanisms that may contribute, at least in part, to postcampylobacteriosis inflammatory disorders.
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19
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Cosentino K, Ros U, García-Sáez AJ. Assembling the puzzle: Oligomerization of α-pore forming proteins in membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:457-466. [PMID: 26375417 DOI: 10.1016/j.bbamem.2015.09.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/26/2015] [Accepted: 09/09/2015] [Indexed: 12/21/2022]
Abstract
Pore forming proteins (PFPs) share the ability of creating pores that allow the passage of ions, proteins or other constituents through a wide variety of target membranes, ranging from bacteria to humans. They often cause cell death, as pore formation disrupts the membrane permeability barrier required for maintaining cell homeostasis. The organization into supramolecular complexes or oligomers that pierce the membrane is a common feature of PFPs. However, the molecular pathway of self-assembly and pore opening remains unclear. Here, we review the most recent discoveries in the mechanism of membrane oligomerization and pore formation of a subset of PFPs, the α-PFPs, whose pore-forming domains are formed by helical segments. Only now we are starting to grasp the molecular details of their function, mainly thanks to the introduction of single molecule microscopy and nanoscopy techniques. This article is part of a Special Issue entitled: Pore-forming toxins edited by Mauro Dalla Serra and Franco Gambale.
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Affiliation(s)
- Katia Cosentino
- Interfaculty Institute of Biochemistry (IFIB), University of Tübingen, Tübingen, Germany.,Max-Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Uris Ros
- Interfaculty Institute of Biochemistry (IFIB), University of Tübingen, Tübingen, Germany.,Max-Planck Institute for Intelligent Systems, Stuttgart, Germany.,Center for Protein Studies, Havana University, Havana, Cuba
| | - Ana J García-Sáez
- Interfaculty Institute of Biochemistry (IFIB), University of Tübingen, Tübingen, Germany.,Max-Planck Institute for Intelligent Systems, Stuttgart, Germany
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20
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Green J, Rolfe MD, Smith LJ. Transcriptional regulation of bacterial virulence gene expression by molecular oxygen and nitric oxide. Virulence 2014; 5:794-809. [PMID: 25603427 PMCID: PMC4601167 DOI: 10.4161/viru.27794] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Molecular oxygen (O2) and nitric oxide (NO) are diatomic gases that play major roles in infection. The host innate immune system generates reactive oxygen species and NO as bacteriocidal agents and both require O2 for their production. Furthermore, the ability to adapt to changes in O2 availability is crucial for many bacterial pathogens, as many niches within a host are hypoxic. Pathogenic bacteria have evolved transcriptional regulatory systems that perceive these gases and respond by reprogramming gene expression. Direct sensors possess iron-containing co-factors (iron–sulfur clusters, mononuclear iron, heme) or reactive cysteine thiols that react with O2 and/or NO. Indirect sensors perceive the physiological effects of O2 starvation. Thus, O2 and NO act as environmental cues that trigger the coordinated expression of virulence genes and metabolic adaptations necessary for survival within a host. Here, the mechanisms of signal perception by key O2- and NO-responsive bacterial transcription factors and the effects on virulence gene expression are reviewed, followed by consideration of these aspects of gene regulation in two major pathogens, Staphylococcus aureus and Mycobacterium tuberculosis.
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Key Words
- AIP, autoinducer peptide
- Arc, Aerobic respiratory control
- FNR
- FNR, fumarate nitrate reduction regulator
- GAF, cGMP-specific phosphodiesterase-adenylyl cyclase-FhlA domain
- Isc, iron–sulfur cluster biosynthesis machinery
- Mycobacterium tuberculosis
- NOX, NADPH oxidase
- PAS, Per-Amt-Sim domain
- RNS, reactive nitrogen species
- ROS, reactive oxygen species
- Staphylococcus aureus
- TB, tuberculosis
- WhiB-like proteins
- iNOS, inducible nitric oxide synthase
- iron–sulfur cluster
- nitric oxide sensors
- oxygen sensors
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Affiliation(s)
- Jeffrey Green
- a Krebs Institute; Molecular Biology & Biotechnology; University of Sheffield ; Western Bank , Sheffield , UK
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21
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Roderer D, Benke S, Müller M, Fäh-Rechsteiner H, Ban N, Schuler B, Glockshuber R. Characterization of Variants of the Pore-Forming Toxin ClyA from Escherichia coli Controlled by a Redox Switch. Biochemistry 2014; 53:6357-69. [DOI: 10.1021/bi5007578] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daniel Roderer
- Institute
of Molecular Biology and Biophysics, ETH Zürich, Otto-Stern-Weg
5, CH-8093 Zürich, Switzerland
| | - Stephan Benke
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Marcus Müller
- Institute
of Molecular Biology and Biophysics, ETH Zürich, Otto-Stern-Weg
5, CH-8093 Zürich, Switzerland
| | - Helene Fäh-Rechsteiner
- Institute
of Molecular Biology and Biophysics, ETH Zürich, Otto-Stern-Weg
5, CH-8093 Zürich, Switzerland
| | - Nenad Ban
- Institute
of Molecular Biology and Biophysics, ETH Zürich, Otto-Stern-Weg
5, CH-8093 Zürich, Switzerland
| | - Benjamin Schuler
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Rudi Glockshuber
- Institute
of Molecular Biology and Biophysics, ETH Zürich, Otto-Stern-Weg
5, CH-8093 Zürich, Switzerland
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22
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Lorenz SC, Son I, Maounounen-Laasri A, Lin A, Fischer M, Kase JA. Prevalence of hemolysin genes and comparison of ehxA subtype patterns in Shiga toxin-producing Escherichia coli (STEC) and non-STEC strains from clinical, food, and animal sources. Appl Environ Microbiol 2013; 79:6301-11. [PMID: 23934487 PMCID: PMC3811216 DOI: 10.1128/aem.02200-13] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 07/30/2013] [Indexed: 11/20/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) belonging to certain serogroups (e.g., O157 and O26) can cause serious conditions like hemolytic-uremic syndrome (HUS), but other strains might be equally pathogenic. While virulence factors, like stx and eae, have been well studied, little is known about the prevalence of the E. coli hemolysin genes (hlyA, ehxA, e-hlyA, and sheA) in association with these factors. Hemolysins are potential virulence factors, and ehxA and hlyA have been associated with human illness, but the significance of sheA is unknown. Hence, 435 E. coli strains belonging to 62 different O serogroups were characterized to investigate gene presence and phenotypic expression of hemolysis. We further investigated ehxA subtype patterns in E. coli isolates from clinical, animal, and food sources. While sheA and ehxA were widely distributed, e-hlyA and hlyA were rarely found. Most strains (86.7%) were hemolytic, and significantly more hemolytic (95%) than nonhemolytic strains (49%) carried stx and/or eae (P < 0.0001). ehxA subtyping, as performed by using PCR in combination with restriction fragment length polymorphism analysis, resulted in six closely related subtypes (>94.2%), with subtypes A/D being eae-negative STECs and subtypes B, C, E, and F eae positive. Unexpectedly, ehxA subtype patterns differed significantly between isolates collected from different sources (P < 0.0001), suggesting that simple linear models of exposure and transmission need modification; animal isolates carried mostly subtypes A/C (39.3%/42.9%), food isolates carried mainly subtype A (81.9%), and clinical isolates carried mainly subtype C (66.4%). Certain O serogroups correlated with particular ehxA subtypes: subtype A with O104, O113, and O8; B exclusively with O157; C with O26, O111, and O121.
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Affiliation(s)
- Sandra C. Lorenz
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Division of Microbiology, College Park, Maryland, USA
- University of Hamburg, Hamburg School of Food Science, Institute of Food Chemistry, Hamburg, Germany
| | - Insook Son
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Division of Microbiology, College Park, Maryland, USA
| | - Anna Maounounen-Laasri
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Division of Microbiology, College Park, Maryland, USA
| | - Andrew Lin
- U.S. Food and Drug Administration, San Francisco District Laboratory, Alameda, California, USA
| | - Markus Fischer
- University of Hamburg, Hamburg School of Food Science, Institute of Food Chemistry, Hamburg, Germany
| | - Julie A. Kase
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Division of Microbiology, College Park, Maryland, USA
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23
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Ganash M, Phung D, Sedelnikova SE, Lindbäck T, Granum PE, Artymiuk PJ. Structure of the NheA component of the Nhe toxin from Bacillus cereus: implications for function. PLoS One 2013; 8:e74748. [PMID: 24040335 PMCID: PMC3769298 DOI: 10.1371/journal.pone.0074748] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 08/06/2013] [Indexed: 12/03/2022] Open
Abstract
The structure of NheA, a component of the Bacillus cereus Nhe tripartite toxin, has been solved at 2.05 Å resolution using selenomethionine multiple-wavelength anomalous dispersion (MAD). The structure shows it to have a fold that is similar to the Bacillus cereus Hbl-B and E. coli ClyA toxins, and it is therefore a member of the ClyA superfamily of α-helical pore forming toxins (α-PFTs), although its head domain is significantly enlarged compared with those of ClyA or Hbl-B. The hydrophobic β-hairpin structure that is a characteristic of these toxins is replaced by an amphipathic β-hairpin connected to the main structure via a β-latch that is reminiscent of a similar structure in the β-PFT Staphylococcus aureus α-hemolysin. Taken together these results suggest that, although it is a member of an archetypal α-PFT family of toxins, NheA may be capable of forming a β rather than an α pore.
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Affiliation(s)
- Magdah Ganash
- The Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Danh Phung
- The Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Oslo, Norway
| | - Svetlana E. Sedelnikova
- The Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Toril Lindbäck
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Oslo, Norway
| | - Per Einar Granum
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Oslo, Norway
- * E-mail: (PJA); (PEG)
| | - Peter J. Artymiuk
- The Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
- * E-mail: (PJA); (PEG)
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24
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Fahie M, Romano FB, Chisholm C, Heuck AP, Zbinden M, Chen M. A non-classical assembly pathway of Escherichia coli pore-forming toxin cytolysin A. J Biol Chem 2013; 288:31042-51. [PMID: 24019520 DOI: 10.1074/jbc.m113.475350] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Cytolysin A (ClyA) is an α-pore forming toxin from pathogenic Escherichia coli (E. coli) and Salmonella enterica. Here, we report that E. coli ClyA assembles into an oligomeric structure in solution in the absence of either bilayer membranes or detergents at physiological temperature. These oligomers can rearrange to create transmembrane pores when in contact with detergents or biological membranes. Intrinsic fluorescence measurements revealed that oligomers adopted an intermediate state found during the transition between monomer and transmembrane pore. These results indicate that the water-soluble oligomer represents a prepore intermediate state. Furthermore, we show that ClyA does not form transmembrane pores on E. coli lipid membranes. Because ClyA is delivered to the target host cell in an oligomeric conformation within outer membrane vesicles (OMVs), our findings suggest ClyA forms a prepore oligomeric structure independently of the lipid membrane within the OMV. The proposed model for ClyA represents a non-classical pathway to attack eukaryotic host cells.
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25
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Role of pore-forming toxins in neonatal sepsis. Clin Dev Immunol 2013; 2013:608456. [PMID: 23710203 PMCID: PMC3655490 DOI: 10.1155/2013/608456] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 03/27/2013] [Indexed: 11/17/2022]
Abstract
Protein toxins are important virulence factors contributing to neonatal sepsis. The major pathogens of neonatal sepsis, group B Streptococci, Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus, secrete toxins of different molecular nature, which are key for defining the disease. Amongst these toxins are pore-forming exotoxins that are expressed as soluble monomers prior to engagement of the target cell membrane with subsequent formation of an aqueous membrane pore. Membrane pore formation is not only a means for immediate lysis of the targeted cell but also a general mechanism that contributes to penetration of epithelial barriers and evasion of the immune system, thus creating survival niches for the pathogens. Pore-forming toxins, however, can also contribute to the induction of inflammation and hence to the manifestation of sepsis. Clearly, pore-forming toxins are not the sole factors that drive sepsis progression, but they often act in concert with other bacterial effectors, especially in the initial stages of neonatal sepsis manifestation.
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26
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Oh S, Buddenborg S, Yoder-Himes DR, Tiedje JM, Konstantinidis KT. Genomic diversity of Escherichia isolates from diverse habitats. PLoS One 2012; 7:e47005. [PMID: 23056556 PMCID: PMC3466228 DOI: 10.1371/journal.pone.0047005] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 09/10/2012] [Indexed: 11/19/2022] Open
Abstract
Our understanding of the Escherichia genus is heavily biased toward pathogenic or commensal isolates from human or animal hosts. Recent studies have recovered Escherichia isolates that persist, and even grow, outside these hosts. Although the environmental isolates are typically phylogenetically distinct, they are highly related to and phenotypically indistinguishable from their human counterparts, including for the coliform test. To gain insights into the genomic diversity of Escherichia isolates from diverse habitats, including freshwater, soil, animal, and human sources, we carried out comparative DNA-DNA hybridizations using a multi-genome E. coli DNA microarray. The microarray was validated based on hybridizations with selected strains whose genome sequences were available and used to assess the frequency of microarray false positive and negative signals. Our results showed that human fecal isolates share two sets of genes (n>90) that are rarely found among environmental isolates, including genes presumably important for evading host immune mechanisms (e.g., a multi-drug transporter for acids and antimicrobials) and adhering to epithelial cells (e.g., hemolysin E and fimbrial-like adhesin protein). These results imply that environmental isolates are characterized by decreased ability to colonize host cells relative to human isolates. Our study also provides gene markers that can distinguish human isolates from those of warm-blooded animal and environmental origins, and thus can be used to more reliably assess fecal contamination in natural ecosystems.
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Affiliation(s)
- Seungdae Oh
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Sarah Buddenborg
- Center for Microbial Ecology, Michigan State University, East Lansing, Michigan, United States of America
| | - Deborah R. Yoder-Himes
- Center for Microbial Ecology, Michigan State University, East Lansing, Michigan, United States of America
| | - James M. Tiedje
- Center for Microbial Ecology, Michigan State University, East Lansing, Michigan, United States of America
| | - Konstantinos T. Konstantinidis
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- School of Biology, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- Center for Bioinformatics and Computational Genomics, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- * E-mail:
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27
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Phung D, Ganash M, Sedelnikova SE, Lindbäck T, Granum PE, Artymiuk PJ. Crystallization and preliminary crystallographic analysis of the NheA component of the Nhe toxin from Bacillus cereus. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:1073-6. [PMID: 22949198 PMCID: PMC3433201 DOI: 10.1107/s1744309112030813] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 07/05/2012] [Indexed: 11/10/2022]
Abstract
The nonhaemolytic enterotoxin (Nhe) of Bacillus cereus plays a key role in cases of B. cereus food poisoning. The toxin is comprised of three different proteins: NheA, NheB and NheC. Here, the expression in Escherichia coli, purification and crystallization of the NheA protein are reported. The protein was crystallized by the sitting-drop vapour-diffusion method using PEG 3350 as a precipitant. The crystals of NheA diffracted to 2.05 Å resolution and belonged to space group C2, with unit-cell parameters a = 308.7, b = 58.2, c = 172.9 Å, β = 110.6°. Calculation of V(M) values suggests that there are approximately eight protein molecules per asymmetric unit.
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Affiliation(s)
- Danh Phung
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, P.O. Box 8146 Dep, 0033 Oslo, Norway
| | - Magdah Ganash
- The Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, England
| | - Svetlana E. Sedelnikova
- The Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, England
| | - Toril Lindbäck
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, P.O. Box 8146 Dep, 0033 Oslo, Norway
| | - Per Einar Granum
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, P.O. Box 8146 Dep, 0033 Oslo, Norway
| | - Peter J. Artymiuk
- The Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, England
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Fuchs TM, Eisenreich W, Heesemann J, Goebel W. Metabolic adaptation of human pathogenic and related nonpathogenic bacteria to extra- and intracellular habitats. FEMS Microbiol Rev 2012; 36:435-62. [DOI: 10.1111/j.1574-6976.2011.00301.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 07/21/2011] [Indexed: 01/02/2023] Open
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29
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Martínez-Peñafiel E, Fernández-Ramírez F, Ishida C, Reyes-Cortés R, Sepúlveda-Robles O, Guarneros-Peña G, Bermúdez-Cruz RM, Kameyama L. Overexpression of Ipe protein from the coliphage mEp021 induces pleiotropic effects involving haemolysis by HlyE-containing vesicles and cell death. Biochimie 2012; 94:1262-73. [PMID: 22365985 DOI: 10.1016/j.biochi.2012.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 02/02/2012] [Indexed: 12/21/2022]
Abstract
Lysogenic Escherichia coli K-12 harbouring the prophage mEp021 displays haemolytic activity. From a genomic library of mEp021, we identified an open reading frame (ORF 4) that was responsible for the haemolytic activity. However, the ORF 4 sequence contains four initiation codons in the same frame: ORF 4.1-ORF 4.4, coding for 83-a.a., 82-a.a., 77-a.a. and 72-a.a. products, respectively. The expression of the cloned ORF 4.3, or inducer of pleiotropic effects (ipe), reproduced the haemolytic phenotype in a native strain carrying the gene hlyE(+), but not in the mutant hlyE(-) strain. The overexpression of Ipe induced several pleiotropic effects, such as the inhibition of cell growth and the deregulation of cell division, which resulted in a mixture of normal and desiccated-like cells: normal-filamentous, desiccated-like-filamentous bacilli, minicells etc. Other effects included abnormalities of the cell membrane, the production of vesicles containing HlyE, and finally, cell death. These events were analysed at the molecular level by microarray assays. The global transcription profile of E. coli K-12 strain MC4100, which expressed Ipe after 4 h, revealed differential expression of various genes, most of which were related either to cell membrane and murein biosynthesis or to cell division. The up-regulation of some of these transcripts was confirmed by qRT-PCR. Additional research is needed to determine whether these effects are directly related to Ipe activity or are consequences of the cellular responses to putative structural damage induced by Ipe.
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Affiliation(s)
- Eva Martínez-Peñafiel
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico Nacional No. 2508, C.P. 07360, México D.F., Mexico
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30
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Magalhães CA, Rossato SS, Barbosa AS, Santos TOD, Elias WP, Sircili MP, Piazza RMF. The ability of haemolysins expressed by atypical enteropathogenic Escherichia coli to bind to extracellular matrix components. Mem Inst Oswaldo Cruz 2011; 106:146-52. [PMID: 21537672 DOI: 10.1590/s0074-02762011000200005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Accepted: 12/01/2010] [Indexed: 01/29/2023] Open
Abstract
Typical and atypical enteropathogenic Escherichia coli (EPEC) are considered important bacterial causes of diarrhoea. Considering the repertoire of virulence genes, atypical EPEC (aEPEC) is a heterogeneous group, harbouring genes that are found in other diarrheagenic E. coli pathotypes, such as those encoding haemolysins. Haemolysins are cytolytic toxins that lyse host cells disrupting the function of the plasma membrane. In addition, these cytolysins mediate a connection to vascular tissue and/or blood components, such as plasma and cellular fibronectin. Therefore, we investigated the haemolytic activity of 72 aEPEC isolates and determined the correlation of this phenotype with the presence of genes encoding enterohaemolysins (Ehly) and cytolysin A (ClyA). In addition, the correlation between the expression of haemolysins and the ability of these secreted proteins to adhere to extracellular matrix (ECM) components was also assessed in this study. Our findings demonstrate that a subset of aEPEC presents haemolytic activity due to the expression of Ehlys and/or ClyA and that this activity is closely related to the ability of these isolates to bind to ECM components.
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31
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Conversion of commensal Escherichia coli K-12 to an invasive form via expression of a mutant histone-like protein. mBio 2011; 2:mBio.00182-11. [PMID: 21896677 PMCID: PMC3172693 DOI: 10.1128/mbio.00182-11] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The HUαE38K, V42L mutant of the bacterial histone-like protein HU causes a major change in the transcription profile of the commensal organism Escherichia coli K-12 (Kar S, Edgar R, Adhya S, Proc. Natl. Acad. Sci. U. S. A. 102:16397–16402, 2005). Among the upregulated genes are several related to pathogenic interactions with mammalian cells, as evidenced by the expression of curli fibers, Ivy, and hemolysin E. When E. coli K-12/ HUαE38K, V42L was added to Int-407 cells, there was host cell invasion, phagosomal disruption, and intracellular replication. The invasive trait was also retained in a murine ileal loop model and intestinal explant assays. In addition to invasion, the internalized bacteria caused a novel subversion of host cell apoptosis through modification and regulation of the BH3-only proteins BimEL and Puma. Changes in the transcription profile were attributed to positive supercoiling of DNA leading to the altered availability of relevant promoters. Using the E. coli K-12/HUαE38K, V42L variant as a model, we propose that traditional commensal E. coli can adopt an invasive lifestyle through reprogramming its cellular transcription, without gross genetic changes. Escherichia coli K-12 is well established as a benign laboratory strain and a human intestinal commensal. Recent evidences, however, indicate that the typical noninvasive nature of resident E. coli can be reversed under specific circumstances even in the absence of any major genomic flux. We previously engineered an E. coli strain with a mutant histone-like protein, HU, which exhibited significant changes in nucleoid organization and global transcription. Here we showed that the changes induced by the mutant HU have critical functional consequences: from a strict extracellular existence, the mutant E. coli adopts an almost obligate intracellular lifestyle. The internalized E. coli exhibits many of the prototypical characteristics of traditional intracellular bacteria, like phagosomal escape, intracellular replication, and subversion of host cell apoptosis. We suggest that E. coli K-12 can switch between widely divergent lifestyles in relation to mammalian host cells by reprogramming its cellular transcription program and without gross changes in its genomic content.
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32
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Haug TM, Sand SL, Sand O, Phung D, Granum PE, Hardy SP. Formation of very large conductance channels by Bacillus cereus Nhe in Vero and GH(4) cells identifies NheA + B as the inherent pore-forming structure. J Membr Biol 2010; 237:1-11. [PMID: 20821199 PMCID: PMC2947714 DOI: 10.1007/s00232-010-9298-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Accepted: 08/13/2010] [Indexed: 11/30/2022]
Abstract
The nonhemolytic enterotoxin (Nhe) produced by Bacillus cereus is a pore-forming toxin consisting of three components, NheA, -B and -C. We have studied effects of Nhe on primate epithelial cells (Vero) and rodent pituitary cells (GH4) by measuring release of lactate dehydrogenase (LDH), K+ efflux and the cytosolic Ca2+ concentration ([Ca2+]i). Plasma membrane channel events were monitored by patch-clamp recordings. Using strains of B. cereus lacking either NheA or -C, we examined the functional role of the various components. In both cell types, NheA + B + C induced release of LDH and K+ as well as Ca2+ influx. A specific monoclonal antibody against NheB abolished LDH release and elevation of [Ca2+]i. Exposure to NheA + B caused a similar K+ efflux and elevation of [Ca2+]i as NheA + B + C in GH4 cells, whereas in Vero cells the rate of K+ efflux was reduced by 50% and [Ca2+]i was unaffected. NheB + C had no effect on either cell type. Exposure to NheA + B + C induced large-conductance steps in both cell types, and similar channel insertions were observed in GH4 cells exposed to NheA + B. In Vero cells, NheA + B induced channels of much smaller conductance. NheB + C failed to insert membrane channels. The conductance of the large channels in GH4 cells was about 10 nS. This is the largest channel conductance reported in cell membranes under quasi-physiological conditions. In conclusion, NheA and NheB are necessary and sufficient for formation of large-conductance channels in GH4 cells, whereas in Vero cells such large-conductance channels are in addition dependent on NheC.
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Affiliation(s)
- Trude M Haug
- Department of Molecular Biosciences, University of Oslo, Post Box 1041, 0316 Oslo, Norway.
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33
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Characterization of anti-Salmonella enterica serotype Typhi antibody responses in bacteremic Bangladeshi patients by an immunoaffinity proteomics-based technology. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2010; 17:1188-95. [PMID: 20573880 DOI: 10.1128/cvi.00104-10] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Salmonella enterica serotype Typhi is the cause of typhoid fever and a human-restricted pathogen. Currently available typhoid vaccines provide 50 to 90% protection for 2 to 5 years, and available practical diagnostic assays to identify individuals with typhoid fever lack sensitivity and/or specificity. Identifying immunogenic S. Typhi antigens expressed during human infection could lead to improved diagnostic assays and vaccines. Here we describe a platform immunoaffinity proteomics-based technology (IPT) that involves the use of columns charged with IgG, IgM, or IgA antibody fractions recovered from humans bacteremic with S. Typhi to capture S. Typhi proteins that were subsequently identified by mass spectrometry. This screening tool identifies immunogenic proteins recognized by antibodies from infected hosts. Using this technology and the plasma of patients with S. Typhi bacteremia in Bangladesh, we identified 57 proteins of S. Typhi, including proteins known to be immunogenic (PagC, HlyE, OmpA, and GroEL) and a number of proteins present in the human-restricted serotypes S. Typhi and S. Paratyphi A but rarely found in broader-host-range Salmonella spp. (HlyE, CdtB, PltA, and STY1364). We categorized identified proteins into a number of major groupings, including those involved in energy metabolism, protein synthesis, iron homeostasis, and biosynthetic and metabolic functions and those predicted to localize to the outer membrane. We assessed systemic and mucosal anti-HlyE responses in S. Typhi-infected patients and detected anti-HlyE responses at the time of clinical presentation in patients but not in controls. These findings could assist in the development of improved diagnostic assays.
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34
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Mutations affecting export and activity of cytolysin A from Escherichia coli. J Bacteriol 2010; 192:4001-11. [PMID: 20511497 DOI: 10.1128/jb.01283-09] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cytolysin A (known as ClyA, HlyE, and SheA) is a cytolytic pore-forming protein toxin found in several Escherichia coli and Salmonella enterica strains. The structure of its water-soluble monomeric form and that of dodecameric ClyA pores is known, but the mechanisms of ClyA export from bacterial cells and of pore assembly are only partially understood. Here we used site-directed mutagenesis to study the importance of different regions of the E. coli ClyA protein for export and activity. The data indicate that ClyA translocation to the periplasm requires several protein segments located closely adjacent to each other in the "tail" domain of the ClyA monomer, namely, the N- and C-terminal regions and the hydrophobic sequence ranging from residues 89 to 101. Deletion of most of the "head" domain of the monomer (residues 181 to 203), on the other hand, did not strongly affect ClyA secretion, suggesting that the tail domain plays a particular role in export. Furthermore, we found that the N-terminal amphipathic helix alphaA1 of ClyA is crucial for the formation and the properties of the transmembrane channel, and hence for hemolytic activity. Several mutations affecting the C-terminal helix alphaG, the "beta-tongue" region in the head domain, or the hydrophobic region in the tail domain of the ClyA monomer strongly impaired the hemolytic activity and reduced the activity toward planar lipid bilayer membranes but did not totally prevent formation of wild-type-like channels in these artificial membranes. The latter regions thus apparently promote membrane interaction without being directly required for pore formation in a lipid bilayer.
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35
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Inhibition of tumor growth and metastasis by a combination of Escherichia coli-mediated cytolytic therapy and radiotherapy. Mol Ther 2010; 18:635-42. [PMID: 20051939 DOI: 10.1038/mt.2009.295] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We have reported that Escherichia coli K-12 colonizes hypoxic and necrotic tumor regions after intravenous injection into tumor-bearing mice. In this study, we established a novel strategy for cancer therapy using engineered bacteria to enhance the therapeutic effects of radiation. E. coli strain K-12 was engineered to produce cytolysin A (ClyA), and its effects on tumor growth in primary and metastatic tumor models were evaluated. A single treatment with E. coli-expressing ClyA significantly decreased tumor growth rates initially (9 days after treatment); however, the tumors tended to grow thereafter. With only radiotherapy (RT; 21 Gy), the tumor growth rates were retarded, but not the tumor sizes. A combination of therapy with E. coli-expressing ClyA and radiation [a total of 5 x 10(7) colony-forming units (CFU) and 21 Gy] resulted in significant tumor shrinkage and even complete disappearance of tumors in mice with tumors derived from murine CT26 colon cancer. Furthermore, treatment with E. coli-expressing ClyA markedly suppressed metastatic tumor growth and prolonged the survival time in mice. The results described here indicate that therapy with engineered E. coli could significantly improve the results of RT, and could exert a striking inhibitory effect on the development of lung metastasis.
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36
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Hunt S, Green J, Artymiuk PJ. Hemolysin E (HlyE, ClyA, SheA) and Related Toxins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 677:116-26. [DOI: 10.1007/978-1-4419-6327-7_10] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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37
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Silva E, Leitão S, Tenreiro T, Pomba C, Nunes T, Lopes da Costa L, Mateus L. Genomic and phenotypic characterization of Escherichia coli isolates recovered from the uterus of puerperal dairy cows. J Dairy Sci 2009; 92:6000-10. [DOI: 10.3168/jds.2009-2358] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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38
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Fuentes JA, Jofré MR, Villagra NA, Mora GC. RpoS- and Crp-dependent transcriptional control of Salmonella Typhi taiA and hlyE genes: role of environmental conditions. Res Microbiol 2009; 160:800-8. [PMID: 19835951 DOI: 10.1016/j.resmic.2009.09.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 09/23/2009] [Accepted: 09/24/2009] [Indexed: 10/20/2022]
Abstract
A novel pathogenicity island, SPI-18, carries the taiA-hlyE operon, encoding virulence factors in Salmonella Typhi. To determine the effects of certain environmental conditions on the expression of these genes, beta-galactosidase assays, RT-PCR reactions, western blot analyses and measurement of hemolytic activity were performed. The conditions studied are those likely found by S. Typhi during infection in the human host. We found RpoS-dependent transcriptional upregulation in low pH and high osmolarity for both genes. Our results show that oxygen depletion apparently did not affect transcription of the taiA-hlyE operon. On the other hand, the transcriptional regulator Crp, previously described as an activator of hlyE transcription in Escherichia coli, is involved in transcriptional repression of hlyE in S. Typhi. Moreover, addition of glucose to the growth medium results in decreasing the hlyE mRNA, suggesting that there is another factor related to catabolite repression different from Crp and involved in downregulation of hlyE in S. Typhi.
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Affiliation(s)
- Juan A Fuentes
- Laboratorio de Microbiología, Facultad de Ciencias Biológicas y Facultad de Medicina, Universidad Andres Bello, República 217, Santiago de Chile, Chile.
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39
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Charles RC, Harris JB, Chase MR, Lebrun LM, Sheikh A, LaRocque RC, Logvinenko T, Rollins SM, Tarique A, Hohmann EL, Rosenberg I, Krastins B, Sarracino DA, Qadri F, Calderwood SB, Ryan ET. Comparative proteomic analysis of the PhoP regulon in Salmonella enterica serovar Typhi versus Typhimurium. PLoS One 2009; 4:e6994. [PMID: 19746165 PMCID: PMC2736619 DOI: 10.1371/journal.pone.0006994] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 07/24/2009] [Indexed: 12/20/2022] Open
Abstract
Background S. Typhi, a human-restricted Salmonella
enterica serovar, causes a systemic intracellular infection in
humans (typhoid fever). In comparison, S. Typhimurium
causes gastroenteritis in humans, but causes a systemic typhoidal illness in
mice. The PhoP regulon is a well studied two component (PhoP/Q) coordinately
regulated network of genes whose expression is required for intracellular
survival of S. enterica. Methodology/Principal Findings Using high performance liquid chromatography mass spectrometry (HPLC-MS/MS),
we examined the protein expression profiles of three sequenced S.
enterica strains: S. Typhimurium LT2,
S. Typhi CT18, and S. Typhi Ty2 in
PhoP-inducing and non-inducing conditions in vitro and
compared these results to profiles of
phoP−/Q−
mutants derived from S. Typhimurium LT2 and
S. Typhi Ty2. Our analysis identified 53 proteins in
S. Typhimurium LT2 and 56 proteins in
S. Typhi that were regulated in a PhoP-dependent manner. As
expected, many proteins identified in S. Typhi demonstrated
concordant differential expression with a homologous protein in
S. Typhimurium. However, three proteins (HlyE, STY1499, and
CdtB) had no homolog in S. Typhimurium. HlyE is a
pore-forming toxin. STY1499 encodes a stably expressed protein of unknown
function transcribed in the same operon as HlyE. CdtB is a cytolethal
distending toxin associated with DNA damage, cell cycle arrest, and cellular
distension. Gene expression studies confirmed up-regulation of mRNA of HlyE,
STY1499, and CdtB in S. Typhi in PhoP-inducing
conditions. Conclusions/Significance This study is the first protein expression study of the PhoP virulence
associated regulon using strains of Salmonella mutant in
PhoP, has identified three Typhi-unique proteins (CdtB, HlyE and STY1499)
that are not present in the genome of the wide host-range Typhimurium, and
includes the first protein expression profiling of a live attenuated
bacterial vaccine studied in humans (Ty800).
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Affiliation(s)
- Richelle C Charles
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA.
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40
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Abstract
Polymorphonuclear leukocytes (PMNs) are the most abundant white cell in humans and an essential component of the innate immune system. PMNs are typically the first type of leukocyte recruited to sites of infection or areas of inflammation. Ingestion of microorganisms triggers production of reactive oxygen species and fusion of cytoplasmic granules with forming phagosomes, leading to effective killing of ingested microbes. Phagocytosis of bacteria typically accelerates neutrophil apoptosis, which ultimately promotes the resolution of infection. However, some bacterial pathogens alter PMN apoptosis to survive and thereby cause disease. Herein, we review PMN apoptosis and the ability of microorganisms to alter this important process.
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Affiliation(s)
- Adam D Kennedy
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th Street, Hamilton, MT 59840, USA
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41
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Mueller M, Grauschopf U, Maier T, Glockshuber R, Ban N. The structure of a cytolytic α-helical toxin pore reveals its assembly mechanism. Nature 2009; 459:726-30. [DOI: 10.1038/nature08026] [Citation(s) in RCA: 263] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 03/24/2009] [Indexed: 11/09/2022]
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Asakura Y, Kobayashi I. From damaged genome to cell surface: transcriptome changes during bacterial cell death triggered by loss of a restriction-modification gene complex. Nucleic Acids Res 2009; 37:3021-31. [PMID: 19304752 PMCID: PMC2685091 DOI: 10.1093/nar/gkp148] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Genetically programmed cell deaths play important roles in unicellular prokaryotes. In postsegregational killing, loss of a gene complex from a cell leads to its descendants' deaths. With type II restriction-modification gene complexes, such death is triggered by restriction endonuclease's attacks on under-methylated chromosomes. Here, we examined how the Escherichia coli transcriptome changes after loss of PaeR7I gene complex. At earlier time points, activation of SOS genes and sigma(E)-regulon was noticeable. With time, more SOS genes, stress-response genes (including sigma(S)-regulon, osmotic-, oxidative- and periplasmic-stress genes), biofilm-related genes, and many hitherto uncharacterized genes were induced, and genes for energy metabolism, motility and outer membrane biogenesis were repressed. As expected from the activation of sigma(E)-regulon, the death was accompanied by cell lysis and release of cellular proteins. Expression of several sigma(E)-regulon genes indeed led to cell lysis. We hypothesize that some signal was transduced, among multiple genes involved, from the damaged genome to the cell surface and led to its disintegration. These results are discussed in comparison with other forms of programmed deaths in bacteria and eukaryotes.
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Affiliation(s)
- Yoko Asakura
- Ajinomoto CO, INC, Kawasaki-shi, Kanagawa, Japan.
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43
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A peptide derived from the putative transmembrane domain in the tail region of E. coli toxin hemolysin E assembles in phospholipid membrane and exhibits lytic activity to human red blood cells: Plausible implications in the toxic activity of the protein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:538-50. [DOI: 10.1016/j.bbamem.2008.11.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 11/06/2008] [Accepted: 11/19/2008] [Indexed: 11/21/2022]
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Faucher SP, Forest C, Béland M, Daigle F. A novel PhoP-regulated locus encoding the cytolysin ClyA and the secreted invasin TaiA of Salmonella enterica serovar Typhi is involved in virulence. Microbiology (Reading) 2009; 155:477-488. [DOI: 10.1099/mic.0.022988-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Salmonella enterica serovar Typhi causes a human-restricted systemic infection called typhoid fever. We have identified a Typhi genomic region encoding two ORFs, STY1498 and STY1499, that are expressed during infection of human macrophages and organized in an operon. STY1498 corresponds to clyA, which encodes a pore-forming cytolysin, and STY1499 encodes a 27 kDa protein, without any attributed function, which we have named TaiA (Typhi-associated invasin A). In order to evaluate the roles of these genes in Typhi pathogenesis, isogenic Typhi strains harbouring a non-polar mutation of either clyA or taiA were constructed. In macrophages, taiA was involved in increasing phagocytosis, as taiA deletion reduced bacterial uptake, whereas clyA reduced or controlled bacterial growth, as clyA deletion enhanced Typhi survival within macrophages without affecting cytotoxicity. In epithelial cells, deletion of taiA had no effect on invasion, whereas deletion of clyA enhanced the Typhi invasion rate, and reduced cytotoxicity. Overexpression of taiA in Typhi or in Escherichia coli resulted in a higher invasion rate of epithelial cells. We have demonstrated that TaiA is secreted independently of both the Salmonella pathogenicity island (SPI)-1 and the SPI-2 type three secretion systems. We have shown that this operon is regulated by the virulence-associated regulator PhoP. Moreover, our results revealed that products of this operon might be involved in promoting the use of macrophages as a sheltered reservoir for Typhi and allowing long-term persistence inside the host.
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Affiliation(s)
- Sébastien P. Faucher
- Department of Microbiology and Immunology, University of Montreal, CP 6128 Succursale Centre-Ville, Montréal, QC H3C 3J7, Canada
| | - Chantal Forest
- Department of Microbiology and Immunology, University of Montreal, CP 6128 Succursale Centre-Ville, Montréal, QC H3C 3J7, Canada
| | - Maxime Béland
- Department of Microbiology and Immunology, University of Montreal, CP 6128 Succursale Centre-Ville, Montréal, QC H3C 3J7, Canada
| | - France Daigle
- Department of Microbiology and Immunology, University of Montreal, CP 6128 Succursale Centre-Ville, Montréal, QC H3C 3J7, Canada
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Kouokam JC, Wai SN. OUTER MEMBRANE VESICLE-MEDIATED EXPORT OF A PORE-FORMING CYTOTOXIN FROM ESCHERICHIA COLI. TOXIN REV 2008. [DOI: 10.1080/15569540500320888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Hunt S, Moir AJG, Tzokov S, Bullough PA, Artymiuk PJ, Green J. The formation and structure of Escherichia coli K-12 haemolysin E pores. Microbiology (Reading) 2008; 154:633-642. [DOI: 10.1099/mic.0.2007/011700-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Stuart Hunt
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Arthur J. G. Moir
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Svetomir Tzokov
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Per A. Bullough
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Peter J. Artymiuk
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Jeffrey Green
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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Ludwig A, von Rhein C, Mischke A, Brade V. Release of latent ClyA cytolysin from Escherichia coli mediated by a bacteriophage-associated putative holin (BlyA) from Borrelia burgdorferi. Int J Med Microbiol 2007; 298:473-81. [PMID: 17897882 DOI: 10.1016/j.ijmm.2007.07.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 06/06/2007] [Accepted: 07/13/2007] [Indexed: 11/22/2022] Open
Abstract
Introduction of the Borrelia burgdorferi blyAB locus into Escherichia coli has recently been reported to cause a hemolytic phenotype that is dependent on the E. coli clyA (hlyE, sheA) gene (a cytolysin gene present in many E. coli strains, including E. coli K-12, which is repressed under standard in vitro growth conditions). The blyA gene product has been suggested to be a prophage-encoded holin, but the processes triggered in E. coli by the expression of blyA and/or blyB, which lead to the hemolytic phenotype, remained unclear. Here we show that expression of blyA in E. coli causes damage to the E. coli cell envelope and a clyA-dependent hemolytic phenotype, regardless whether blyB is present or absent. The expression of blyB in E. coli, on the other hand, did not have obvious phenotypic effects. Transcriptional studies demonstrated that the clyA gene is not induced in E. coli cells expressing blyA. Furthermore, protein analyses suggested that the impairment of the E. coli cell envelope by BlyA is responsible for the emergence of the hemolytic activity as it allows latent intracellular ClyA protein, derived from basal-level expression of the clyA gene, to leak into the medium and to lyse erythrocytes. These findings are compatible with the presumption that BlyA functions as a membrane-active holin.
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Affiliation(s)
- Albrecht Ludwig
- Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Klinikum der Johann Wolfgang Goethe-Universität Frankfurt am Main, Paul-Ehrlich-Str. 40, D-60596 Frankfurt am Main, Germany.
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48
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Lithgow JK, Haider F, Roberts IS, Green J. Alternate SlyA and H-NS nucleoprotein complexes control hlyE expression in Escherichia coli K-12. Mol Microbiol 2007; 66:685-98. [PMID: 17892462 PMCID: PMC2156107 DOI: 10.1111/j.1365-2958.2007.05950.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Haemolysin E is a cytolytic pore-forming toxin found in several Escherichia coli and Salmonella enterica strains. Expression of hlyE is repressed by the global regulator H-NS (histone-like nucleoid structuring protein), but can be activated by the regulator SlyA. Expression of a chromosomal hlyE–lacZ fusion in an E. coli slyA mutant was reduced to 60% of the wild-type level confirming a positive role for SlyA. DNase I footprint analysis revealed the presence of two separate SlyA binding sites, one located upstream, the other downstream of the hlyE transcriptional start site. These sites overlap AT-rich H-NS binding sites. Footprint and gel shift data showed that whereas H-NS prevented binding of RNA polymerase (RNAP) at the hlyE promoter (PhlyE), SlyA allowed binding of RNAP, but inhibited binding of H-NS. Accordingly, in vitro transcription analyses showed that addition of SlyA protein relieved H-NS-mediated repression of hlyE. Based on these observations a model for SlyA/H-NS regulation of hlyE expression is proposed in which the relative concentrations of SlyA and H-NS govern the nature of the nucleoprotein complexes formed at PhlyE. When H-NS is dominant RNAP binding is inhibited and hlyE expression is silenced; when SlyA is dominant H-NS binding is inhibited allowing RNAP access to the promoter facilitating hlyE transcription.
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Affiliation(s)
- James K Lithgow
- Department of Molecular Biology and Biotechnology, The University of SheffieldWestern Bank, Sheffield S10 2TN, UK.
| | - Fouzia Haider
- Department of Molecular Biology and Biotechnology, The University of SheffieldWestern Bank, Sheffield S10 2TN, UK.
| | - Ian S Roberts
- 1.800 Stopford Building, Faculty of Life Sciences, University of ManchesterOxford Road, Manchester M13 9PT, UK.
| | - Jeffrey Green
- Department of Molecular Biology and Biotechnology, The University of SheffieldWestern Bank, Sheffield S10 2TN, UK.
- For correspondence. E-mail ; Tel. (+44) 114 222 4403; Fax (+44) 0114 222 2800
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49
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Yadav SP, Ahmad A, Ghosh JK. Addition of a small hydrophobic segment from the head region to an amphipathic leucine zipper like motif of E. coli toxin hemolysin E enhances the peptide-induced permeability of zwitterionic lipid vesicles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1574-82. [PMID: 17467657 DOI: 10.1016/j.bbamem.2007.03.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 02/28/2007] [Accepted: 03/20/2007] [Indexed: 11/30/2022]
Abstract
To find out the sequence requirement of the H-205 peptide, containing an amphipathic leucine zipper motif corresponding to the amino acid (a.a.) region 205-234 of hemolysin E (HlyE) to induce efficient permeation in zwitterionic lipid vesicles, the peptide was extended at the N-terminal after the addition of seven amino acids from the predicted transmembrane region in the head domain of the protein-toxin. The new peptide, H-198 (a.a. 198-234) and a scrambled mutant peptide of the same size were synthesized, fluorescently labeled and characterized functionally and structurally. The results showed that H-198 induced significantly higher permeation in the zwitterionic PC/Chol lipid vesicles than its shorter version, H-205. H-198 formed large aggregates in the PC/Chol vesicles unlike H-205 and also adopted more helical structure in the membrane mimetic environments compared to that of H-205. Fluorescence energy transfer experiments by flow cytometry indicated that only H-198 but not its mutant or H-205 oligomerized in the zwitterionic lipid vesicles, while in the negatively charged lipid vesicles both H-198 and H-205 formed oligomeric assembly. The results suggest a probable role of the hydrophobic residues of the head domain of HlyE in inducing permeability in the zwitterionic lipid vesicles by the peptide derived from the a.a. 198-234 of the toxin.
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Affiliation(s)
- Sharada Prasad Yadav
- Molecular and Structural Biology Division, Central Drug Research Institute, Lucknow-226001, India
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50
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Derrick SC, Morris SL. The ESAT6 protein of Mycobacterium tuberculosis induces apoptosis of macrophages by activating caspase expression. Cell Microbiol 2007; 9:1547-55. [PMID: 17298391 DOI: 10.1111/j.1462-5822.2007.00892.x] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The secreted Mycobacterium tuberculosis protein, ESAT6, has been studied extensively in pathogenicity and vaccine experiments. Despite these studies little is known about the function of this protein. In this report, we demonstrate that ESAT6 induces apoptosis in THP-1 human macrophages using fluorescein isothiocyanate-Annexin V and intracellular caspase staining. We show that the induction of apoptosis by ESAT6 is dependent on the dose of the protein and the expression of caspase genes. Using real-time RT-PCR, we found that expression of caspase-1, -3, -5, -7 and -8 genes was upregulated in cells treated with ESAT6 relative to untreated cells. Furthermore, we show that while infection of THP-1 cells with wild-type M. tuberculosis strain H37Rv resulted in significant apoptosis 48 h post infection, a deletion mutant that does not express ESAT6 failed to induce significant apoptosis. Finally, experimental results using a cell impermeable fluorescent stain suggests that the formation of membrane pores may be a primary mechanism by which ESAT6 evokes an apoptotic response.
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Affiliation(s)
- Steven C Derrick
- Laboratory of Mycobacterial Diseases and Cellular Immunology, Center for Biologics Evaluation and Research, United States Food and Drug Administration, Bethesda, MD 20892, USA.
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