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Hajdú G, Szathmári C, Sőti C. Modeling Host-Pathogen Interactions in C. elegans: Lessons Learned from Pseudomonas aeruginosa Infection. Int J Mol Sci 2024; 25:7034. [PMID: 39000143 PMCID: PMC11241598 DOI: 10.3390/ijms25137034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2024] [Revised: 06/17/2024] [Accepted: 06/22/2024] [Indexed: 07/16/2024] Open
Abstract
Infections, such as that by the multiresistant opportunistic bacterial pathogen Pseudomonas aeruginosa, may pose a serious health risk, especially on vulnerable patient populations. The nematode Caenorhabditis elegans provides a simple organismal model to investigate both pathogenic mechanisms and the emerging role of innate immunity in host protection. Here, we review the virulence and infection strategies of P. aeruginosa and host defenses of C. elegans. We summarize the recognition mechanisms of patterns of pathogenesis, including novel pathogen-associated molecular patterns and surveillance immunity of translation, mitochondria, and lysosome-related organelles. We also review the regulation of antimicrobial and behavioral defenses by the worm's neuroendocrine system. We focus on how discoveries in this rich field align with well-characterized evolutionary conserved protective pathways, as well as on potential crossovers to human pathogenesis and innate immune responses.
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Affiliation(s)
- Gábor Hajdú
- Department of Molecular Biology, Semmelweis University, 1094 Budapest, Hungary
| | - Csenge Szathmári
- Department of Molecular Biology, Semmelweis University, 1094 Budapest, Hungary
| | - Csaba Sőti
- Department of Molecular Biology, Semmelweis University, 1094 Budapest, Hungary
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Ribeiro CMP, Higgs MG, Muhlebach MS, Wolfgang MC, Borgatti M, Lampronti I, Cabrini G. Revisiting Host-Pathogen Interactions in Cystic Fibrosis Lungs in the Era of CFTR Modulators. Int J Mol Sci 2023; 24:ijms24055010. [PMID: 36902441 PMCID: PMC10003689 DOI: 10.3390/ijms24055010] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/25/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) modulators, a new series of therapeutics that correct and potentiate some classes of mutations of the CFTR, have provided a great therapeutic advantage to people with cystic fibrosis (pwCF). The main hindrances of the present CFTR modulators are related to their limitations in reducing chronic lung bacterial infection and inflammation, the main causes of pulmonary tissue damage and progressive respiratory insufficiency, particularly in adults with CF. Here, the most debated issues of the pulmonary bacterial infection and inflammatory processes in pwCF are revisited. Special attention is given to the mechanisms favoring the bacterial infection of pwCF, the progressive adaptation of Pseudomonas aeruginosa and its interplay with Staphylococcus aureus, the cross-talk among bacteria, the bronchial epithelial cells and the phagocytes of the host immune defenses. The most recent findings of the effect of CFTR modulators on bacterial infection and the inflammatory process are also presented to provide critical hints towards the identification of relevant therapeutic targets to overcome the respiratory pathology of pwCF.
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Affiliation(s)
- Carla M. P. Ribeiro
- Marsico Lung Institute/Cystic Fibrosis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Correspondence: (C.M.P.R.); (G.C.)
| | - Matthew G. Higgs
- Marsico Lung Institute/Cystic Fibrosis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Marianne S. Muhlebach
- Marsico Lung Institute/Cystic Fibrosis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Pediatrics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Matthew C. Wolfgang
- Marsico Lung Institute/Cystic Fibrosis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Monica Borgatti
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
- Innthera4CF, Center on Innovative Therapies for Cystic Fibrosis, University of Ferrara, 44121 Ferrara, Italy
| | - Ilaria Lampronti
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
- Innthera4CF, Center on Innovative Therapies for Cystic Fibrosis, University of Ferrara, 44121 Ferrara, Italy
| | - Giulio Cabrini
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
- Innthera4CF, Center on Innovative Therapies for Cystic Fibrosis, University of Ferrara, 44121 Ferrara, Italy
- Correspondence: (C.M.P.R.); (G.C.)
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Li M, Mei S, Yang Y, Shen Y, Chen L. Strategies to mitigate the on- and off-target toxicities of recombinant immunotoxins: an antibody engineering perspective. Antib Ther 2022; 5:164-176. [PMID: 35928456 PMCID: PMC9344849 DOI: 10.1093/abt/tbac014] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/14/2021] [Accepted: 06/14/2022] [Indexed: 11/14/2022] Open
Abstract
Abstract
Targeted cancer therapies using immunotoxins has achieved remarkable efficacies in hematological malignancies. However, the clinical development of immunotoxins is also faced with many challenges like anti-drug antibodies and dose-limiting toxicity issues. Such a poor efficacy/safety ratio is also the major hurdle in the research and development of antibody-drug conjugates. From an antibody engineering perspective, various strategies were summarized/proposed to tackle the notorious on target off tumor toxicity issues, including passive strategy (XTENylation of immunotoxins) and active strategies (modulating the affinity and valency of the targeting moiety of immunotoxins, conditionally activating immunotoxins in the tumor microenvironments and reconstituting split toxin to reduce systemic toxicity etc.). By modulating the functional characteristics of the targeting moiety and the toxic moiety of immunotoxins, selective tumor targeting can be augmented while sparing the healthy cells in normal tissues expressing the same target of interest. If successful, the improved therapeutic index will likely help to address the dose-limiting toxicities commonly observed in the clinical trials of various immunotoxins.
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Affiliation(s)
- Mengyu Li
- Department of Postgraduate , Jiangxi University of Traditional Chinese Medicine, Nanchang, P.R. China
- Joint Graduate School , Yangtze Delta Drug Advanced Research Institute, Nantong, P.R. China
- Joint Graduate School , Yangtze Delta Pharmaceutical College, Nantong, P.R. China
| | - Sen Mei
- Biotherapeutics , Biocytogen Jiangsu Co. Ltd, Nantong, P.R. China
| | - Yi Yang
- Joint Graduate School , Yangtze Delta Drug Advanced Research Institute, Nantong, P.R. China
- Joint Graduate School , Yangtze Delta Pharmaceutical College, Nantong, P.R. China
- Institute of Innovative Medicine , Biocytogen Pharmaceuticals (Beijing) Co, Ltd, Beijing, P.R. China
| | - Yuelei Shen
- Joint Graduate School , Yangtze Delta Drug Advanced Research Institute, Nantong, P.R. China
- Joint Graduate School , Yangtze Delta Pharmaceutical College, Nantong, P.R. China
- Biotherapeutics , Biocytogen Pharmaceuticals (Beijing) Co, Ltd, Beijing, P.R. China
- Institute of Innovative Medicine , Biocytogen Pharmaceuticals (Beijing) Co, Ltd, Beijing, P.R. China
| | - Lei Chen
- Biotherapeutics , Biocytogen Jiangsu Co. Ltd, Nantong, P.R. China
- Biotherapeutics , Biocytogen Pharmaceuticals (Beijing) Co, Ltd, Beijing, P.R. China
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AB 5 Enterotoxin-Mediated Pathogenesis: Perspectives Gleaned from Shiga Toxins. Toxins (Basel) 2022; 14:toxins14010062. [PMID: 35051039 PMCID: PMC8779504 DOI: 10.3390/toxins14010062] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/12/2022] [Accepted: 01/12/2022] [Indexed: 02/01/2023] Open
Abstract
Foodborne diseases affect an estimated 600 million people worldwide annually, with the majority of these illnesses caused by Norovirus, Vibrio, Listeria, Campylobacter, Salmonella, and Escherichia coli. To elicit infections in humans, bacterial pathogens express a combination of virulence factors and toxins. AB5 toxins are an example of such toxins that can cause various clinical manifestations, including dehydration, diarrhea, kidney damage, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Treatment of most bacterial foodborne illnesses consists of fluid replacement and antibiotics. However, antibiotics are not recommended for infections caused by Shiga toxin-producing E. coli (STEC) because of the increased risk of HUS development, although there are conflicting views and results in this regard. Lack of effective treatment strategies for STEC infections pose a public health threat during outbreaks; therefore, the debate on antibiotic use for STEC infections could be further explored, along with investigations into antibiotic alternatives. The overall goal of this review is to provide a succinct summary on the mechanisms of action and the pathogenesis of AB5 and related toxins, as expressed by bacterial foodborne pathogens, with a primary focus on Shiga toxins (Stx). The role of Stx in human STEC disease, detection methodologies, and available treatment options are also briefly discussed.
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Potential Therapeutic Targets for Combination Antibody Therapy against Pseudomonas aeruginosa Infections. Antibiotics (Basel) 2021; 10:antibiotics10121530. [PMID: 34943742 PMCID: PMC8698887 DOI: 10.3390/antibiotics10121530] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/03/2021] [Accepted: 12/09/2021] [Indexed: 12/12/2022] Open
Abstract
Despite advances in antimicrobial therapy and even the advent of some effective vaccines, Pseudomonas aeruginosa (P. aeruginosa) remains a significant cause of infectious disease, primarily due to antibiotic resistance. Although P. aeruginosa is commonly treatable with readily available therapeutics, these therapies are not always efficacious, particularly for certain classes of patients (e.g., cystic fibrosis (CF)) and for drug-resistant strains. Multi-drug resistant P. aeruginosa infections are listed on both the CDC’s and WHO’s list of serious worldwide threats. This increasing emergence of drug resistance and prevalence of P. aeruginosa highlights the need to identify new therapeutic strategies. Combinations of monoclonal antibodies against different targets and epitopes have demonstrated synergistic efficacy with each other as well as in combination with antimicrobial agents typically used to treat these infections. Such a strategy has reduced the ability of infectious agents to develop resistance. This manuscript details the development of potential therapeutic targets for polyclonal antibody therapies to combat the emergence of multidrug-resistant P. aeruginosa infections. In particular, potential drug targets for combinational immunotherapy against P. aeruginosa are identified to combat current and future drug resistance.
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Khirehgesh MR, Sharifi J, Akbari B, Mansouri K, Safari F, Soleymani B, Yari K. Design and construction a novel humanized biparatopic nanobody-based immunotoxin against epidermal growth factor receptor (EGFR). J Drug Deliv Sci Technol 2021. [DOI: 10.1016/j.jddst.2021.102837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abbasi M, Tanomand A, Kafilzadeh F, Zolghadri S, Hosainzadegan H. Preparation and evaluation of the exotoxin A nano-gold conjugate as a vaccine candidate for Pseudomonas aeruginosa infections. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2021; 24:1366-1372. [PMID: 35096294 PMCID: PMC8769522 DOI: 10.22038/ijbms.2021.58367.12960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/01/2021] [Indexed: 11/09/2022]
Abstract
OBJECTIVES Pseudomonas aeruginosa is an opportunistic pathogen that is an important cause of nosocomial infections. This bacterium produces various virulence factors, among which exotoxin A is significantly involved in mortality and morbidity. In this study, we evaluated the immunogenicity of native exotoxin A extracted from the P. aeruginosa and its conjugation with gold nanoparticles in the animal model. MATERIALS AND METHODS Exotoxin A was first extracted and purified from the culture medium of P. aeruginosa PAO1 by selective precipitation and dialysis. The gold nanoparticles were prepared using the Turkevich method and conjugated to the prepared exotoxin A by electrostatic force. The size and conjugation were confirmed using electron microscopy and Fourier transform infrared spectrometry (FTIR), respectively. The immunogenicity of prepared ExoA-gold nanoparticles was investigated in the mice model. RESULTS The results indicated that nano-gold particles can be conjugated to the native exotoxin A with high efficiency. Immunogenicity investigation demonstrated that antibody titers produced against native exotoxin A and its conjugate to nano-gold particles are significant in a mouse model (P<0.005). Moreover, significant protection against 2×LD50 P. aeruginosa infection was observed in animals immunized with nano-gold-exotoxin A as compared with control groups (P=0.00). CONCLUSION Our study indicated that exotoxin A can be produced with acceptable purity in the laboratory, and conjugated to gold nanoparticles. Based on these results nano-gold-exotoxin A conjugate is highly immunogenic and can be considered a potential vaccine candidate for P. aeruginosa infections.
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Affiliation(s)
- Masoumeh Abbasi
- Department of Microbiology, Jahrom Branch, Islamic Azad University, Jahrom, Iran
| | - Asghar Tanomand
- Department of Microbiology, Maragheh University of Medical Sciences, Maragheh, Iran,Corresponding author: Asghar Tanomand.Department of Microbiology, Maragheh University of Medical Sciences, Maragheh Iran. Tel: +98-413-7256900;
| | - Farshid Kafilzadeh
- Department of Microbiology, Jahrom Branch, Islamic Azad University, Jahrom, Iran
| | - Samaneh Zolghadri
- Department of Microbiology, Jahrom Branch, Islamic Azad University, Jahrom, Iran
| | - Hasan Hosainzadegan
- Department of Microbiology, Maragheh University of Medical Sciences, Maragheh, Iran
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Khirehgesh MR, Sharifi J, Safari F, Akbari B. Immunotoxins and nanobody-based immunotoxins: review and update. J Drug Target 2021; 29:848-862. [PMID: 33615933 DOI: 10.1080/1061186x.2021.1894435] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Immunotoxins (ITs) are protein-based drugs that compose of targeting and cytotoxic moieties. After binding the IT to the specific cell-surface antigen, the IT internalises into the target cell and kills it. Targeting and cytotoxic moieties usually include monoclonal antibodies and protein toxins with bacterial or plant origin, respectively. ITs have been successful in haematologic malignancies treatment. However, ITs penetrate poorly into solid tumours because of their large size. Use of camelid antibody fragments known as nanobodies (Nbs) as a targeting moiety may overcome this problem. Nbs are the smallest fragment of antibodies with excellent tumour tissue penetration. The ability to recognise cryptic (immuno-evasive) target antigens, low immunogenicity, and high-affinity are other fundamental characteristics of Nbs that make them suitable candidates in targeted therapy. Here, we reviewed and discussed the structure and function of ITs, Nbs, and nanobody-based ITs. To gain sound insight into the issue at hand, we focussed on nanobody-based ITs.
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Affiliation(s)
- Mohammad Reza Khirehgesh
- Department of Medical Biotechnology, School of Medical Sciences, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Jafar Sharifi
- Department of Medical Biotechnology, School of Medical Sciences, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Fatemeh Safari
- Diagnostic Laboratory Sciences and Technology Research Center, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Bahman Akbari
- Department of Medical Biotechnology, School of Medical Sciences, Kermanshah University of Medical Sciences, Kermanshah, Iran
- Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran
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Islam E. Development of chemokine CXCL12-dependent immunotoxin against small cell lung cancer using in silico approaches. INFORMATICS IN MEDICINE UNLOCKED 2021. [DOI: 10.1016/j.imu.2021.100676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Ogura K, Yahiro K, Moss J. Cell Death Signaling Pathway Induced by Cholix Toxin, a Cytotoxin and eEF2 ADP-Ribosyltransferase Produced by Vibrio cholerae. Toxins (Basel) 2020; 13:toxins13010012. [PMID: 33374361 PMCID: PMC7824611 DOI: 10.3390/toxins13010012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/20/2020] [Accepted: 12/22/2020] [Indexed: 12/14/2022] Open
Abstract
Pathogenic microorganisms produce various virulence factors, e.g., enzymes, cytotoxins, effectors, which trigger development of pathologies in infectious diseases. Cholera toxin (CT) produced by O1 and O139 serotypes of Vibrio cholerae (V. cholerae) is a major cytotoxin causing severe diarrhea. Cholix cytotoxin (Cholix) was identified as a novel eukaryotic elongation factor 2 (eEF2) adenosine-diphosphate (ADP)-ribosyltransferase produced mainly in non-O1/non-O139 V. cholerae. The function and role of Cholix in infectious disease caused by V. cholerae remain unknown. The crystal structure of Cholix is similar to Pseudomonas exotoxin A (PEA) which is composed of an N-terminal receptor-recognition domain and a C-terminal ADP-ribosyltransferase domain. The endocytosed Cholix catalyzes ADP-ribosylation of eEF2 in host cells and inhibits protein synthesis, resulting in cell death. In a mouse model, Cholix caused lethality with severe liver damage. In this review, we describe the mechanism underlying Cholix-induced cytotoxicity. Cholix-induced apoptosis was regulated by mitogen-activated protein kinase (MAPK) and protein kinase C (PKC) signaling pathways, which dramatically enhanced tumor necrosis factor-α (TNF-α) production in human liver, as well as the amount of epithelial-like HepG2 cancer cells. In contrast, Cholix induced apoptosis in hepatocytes through a mitochondrial-dependent pathway, which was not stimulated by TNF-α. These findings suggest that sensitivity to Cholix depends on the target cell. A substantial amount of information on PEA is provided in order to compare/contrast this well-characterized mono-ADP-ribosyltransferase (mART) with Cholix.
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Affiliation(s)
- Kohei Ogura
- Advanced Health Care Science Research Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa 920-0942, Japan
- Correspondence: (K.O.); (K.Y.); Tel.: +81-76-265-2590 (K.O.); +81-43-226-2048 (K.Y.)
| | - Kinnosuke Yahiro
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
- Correspondence: (K.O.); (K.Y.); Tel.: +81-76-265-2590 (K.O.); +81-43-226-2048 (K.Y.)
| | - Joel Moss
- Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1590, USA;
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Vilaplana L, Marco MP. Phenazines as potential biomarkers of Pseudomonas aeruginosa infections: synthesis regulation, pathogenesis and analytical methods for their detection. Anal Bioanal Chem 2020; 412:5897-5912. [PMID: 32462363 DOI: 10.1007/s00216-020-02696-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 04/22/2020] [Accepted: 05/04/2020] [Indexed: 10/24/2022]
Abstract
Infectious diseases are still a worldwide important problem. This fact has led to the characterization of new biomarkers that would allow an early, fast and reliable diagnostic and targeted therapy. In this context, Pseudomonas aeruginosa can be considered one of the most threatening pathogens since it causes a wide range of infections, mainly in patients that suffer other diseases. Antibiotic treatment is not trivial given the incidence of resistance processes and the fewer new antibiotics that are placed on the market. With this scenario, relevant quorum sensing (QS) molecules that regulate the secretion of virulence factors and biofilm formation can play an important role in diagnostic and therapeutic issues. In this review, we have focused our attention on phenazines, as possible new biomarkers. They are pigmented metabolites that are produced by diverse bacteria, characterized for presenting unique redox properties. Phenazines are involved in virulence, competitive fitness and are an essential component of the bacterial QS system. Here we describe their role in bacterial pathogenesis and we revise phenazine production regulation systems. We also discuss phenazine levels previously reported in bacterial isolates and in clinical samples to evaluate them as putative good candidates to be used as P. aeruginosa infection biomarkers. Moreover we deeply go through all analytical techniques that have been used for their detection and also new approaches are discussed from a critical point. Graphical abstract.
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Affiliation(s)
- Lluïsa Vilaplana
- Nanobiotechnology for Diagnostics (Nb4D), Institute of Advanced Chemistry of Catalonia, IQAC-CSIC, Jordi Girona, 18-26, 08034, Barcelona, Spain. .,CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Jordi Girona, 18-26, 08034, Barcelona, Spain.
| | - M-Pilar Marco
- Nanobiotechnology for Diagnostics (Nb4D), Institute of Advanced Chemistry of Catalonia, IQAC-CSIC, Jordi Girona, 18-26, 08034, Barcelona, Spain.,CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Jordi Girona, 18-26, 08034, Barcelona, Spain
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Kim JY, Le TAN, Lee SY, Song DG, Hong SC, Cha KH, Lee JW, Pan CH, Kang K. 3,3'-Diindolylmethane Improves Intestinal Permeability Dysfunction in Cultured Human Intestinal Cells and the Model Animal Caenorhabditis elegans. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:9277-9285. [PMID: 31353906 DOI: 10.1021/acs.jafc.9b03039] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
3,3'-Diindolylmethane (DIM), a digestive metabolite originating from cruciferous vegetables, has dietary potential for the treatment of various human intestinal diseases. Although intestinal permeability dysfunction is closely related to the initiation and progression of human intestinal inflammatory diseases (IBDs), the effect of DIM on intestinal permeability is unclear. We evaluated the effect of DIM on the intestinal permeability of human intestinal cell monolayers and the animal model Caenorhabditis elegans, which were treated with IL-1β and Pseudomonas aeruginosa, respectively, to mimic IBD conditions. DIM substantially restored the intestinal permeability of differentiated Caco-2 cells by enhancing the expression of tight junction proteins (including occludin and ZO-1). Compared to the IL-1β single treatment (551.0 ± 49.0 Ω·cm2), DIM (10 μM) significantly increased the transepithelial electrical resistance (TEER) of Caco-2 cell monolayers (919.0 ± 66.4 Ω·cm2, p < 0.001). DIM also ameliorated the impaired intestinal permeability and extended the lifespan of C. elegans fed P. aeruginosa. The mean lifespan of DIM-treated worms (10.8 ± 1.3 days) was higher than that of control-treated worms (9.7 ± 1.1 days, p < 0.01). Thus, DIM is a potential nutraceutical candidate for the treatment of leaky gut syndrome by improving intestinal permeability.
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Affiliation(s)
- Joo Yeon Kim
- Natural Product Informatics Research Center , Korea Institute of Science and Technology , Gangneung , Gangwon-do 25451 , Republic of Korea
| | - Tram Anh Ngoc Le
- Natural Product Informatics Research Center , Korea Institute of Science and Technology , Gangneung , Gangwon-do 25451 , Republic of Korea
| | - So Young Lee
- Natural Product Informatics Research Center , Korea Institute of Science and Technology , Gangneung , Gangwon-do 25451 , Republic of Korea
| | - Dae-Geun Song
- Natural Product Informatics Research Center , Korea Institute of Science and Technology , Gangneung , Gangwon-do 25451 , Republic of Korea
| | - Sung-Chul Hong
- Natural Product Informatics Research Center , Korea Institute of Science and Technology , Gangneung , Gangwon-do 25451 , Republic of Korea
| | - Kwang Hyun Cha
- Natural Product Informatics Research Center , Korea Institute of Science and Technology , Gangneung , Gangwon-do 25451 , Republic of Korea
| | - Jae Wook Lee
- Natural Products Research Center , Korea Institute of Science and Technology , Gangneung , Gangwon-do 25451 , Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School , Korea University of Science and Technology (UST) , Seoul 02792 , Republic of Korea
| | - Cheol-Ho Pan
- Natural Product Informatics Research Center , Korea Institute of Science and Technology , Gangneung , Gangwon-do 25451 , Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School , Korea University of Science and Technology (UST) , Seoul 02792 , Republic of Korea
| | - Kyungsu Kang
- Natural Product Informatics Research Center , Korea Institute of Science and Technology , Gangneung , Gangwon-do 25451 , Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School , Korea University of Science and Technology (UST) , Seoul 02792 , Republic of Korea
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Yahiro K, Ogura K, Terasaki Y, Satoh M, Miyagi S, Terasaki M, Yamasaki E, Moss J. Cholix toxin, an eukaryotic elongation factor 2 ADP-ribosyltransferase, interacts with Prohibitins and induces apoptosis with mitochondrial dysfunction in human hepatocytes. Cell Microbiol 2019; 21:e13033. [PMID: 31009148 PMCID: PMC9986844 DOI: 10.1111/cmi.13033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 04/16/2019] [Indexed: 12/12/2022]
Abstract
Vibrio cholerae produced-Cholix toxin (Cholix) is a cytotoxin that ADP-ribosylates eukaryotic elongation factor 2, inhibiting protein synthesis, and inducing apoptosis. Here, we identified prohibitin (PHB) 1 and 2 as novel Cholix-interacting membrane proteins in immortalised human hepatocytes and HepG2 cells by Cholix immunoprecipitation assays. The expression level of PHB1 was decreased by Cholix after a 12hr incubation. Cholix-induced poly (ADP-ribose) polymerase (PARP) cleavage was significantly enhanced in PHB (PHB1 or PHB2) knockdown cells. In contrast, transiently overexpressed PHB in hepatocytes attenuated Cholix-induced Bax/Bak conformational changes and PARP cleavage. In addition, Cholix-induced reactive oxygen species production and accumulation of fragmented mitochondria were enhanced in PHB-knockdown cells. Furthermore, Cholix induced activation of Rho-associated coiled coil-containing protein kinase 1 (ROCK1), which was enhanced in PHB-knockdown cells, followed by actin filament depolymerisation and accumulation of tubulin in the blebbing cells. Inhibition of ROCK1 by siRNA or its inhibitor suppressed Cholix-induced PARP cleavage and reactive oxygen species generation. Our findings identify PHB as a new protein that interacts with Cholix and is involved in Cholix-induced mitochondrial dysfunction and cytoskeletal rearrangement by ROCK1 activation during apoptosis.
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Affiliation(s)
- Kinnosuke Yahiro
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Kohei Ogura
- Advanced Health Care Science Research Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Japan
| | - Yasuhiro Terasaki
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - Mamoru Satoh
- Division of Clinical Mass Spectrometry, Chiba University Hospital, Chiba, Japan
| | - Satoru Miyagi
- Department of Life Science, Faculty of Medicine, Shimane University, Izumo, Japan
| | - Mika Terasaki
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - Eiki Yamasaki
- Diagnostic Center for Animal Health and Food Safety, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan
| | - Joel Moss
- Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
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Borowiec M, Gorzkiewicz M, Grzesik J, Walczak-Drzewiecka A, Salkowska A, Rodakowska E, Steczkiewicz K, Rychlewski L, Dastych J, Ginalski K. Towards Engineering Novel PE-Based Immunotoxins by Targeting Them to the Nucleus. Toxins (Basel) 2016; 8:E321. [PMID: 27834892 PMCID: PMC5127118 DOI: 10.3390/toxins8110321] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 11/01/2016] [Accepted: 11/02/2016] [Indexed: 12/23/2022] Open
Abstract
Exotoxin A (PE) from Pseudomonas aeruginosa is a bacterial ADP-ribosyltransferase, which can permanently inhibit translation in the attacked cells. Consequently, this toxin is frequently used in immunotoxins for targeted cancer therapies. In this study, we propose a novel modification to PE by incorporating the NLS sequence at its C-terminus, to make it a selective agent against fast-proliferating cancer cells, as a nucleus-accumulated toxin should be separated from its natural substrate (eEF2) in slowly dividing cells. Here, we report the cytotoxic activity and selected biochemical properties of newly designed PE mutein using two cellular models: A549 and HepG2. We also present a newly developed protocol for efficient purification of recombinant PE and its muteins with very high purity and activity. We found that furin cleavage is not critical for the activity of PE in the analyzed cell lines. Surprisingly, we observed increased toxicity of the toxin accumulated in the nucleus. This might be explained by unexpected nuclease activity of PE and its potential ability to cleave chromosomal DNA, which seems to be a putative alternative intoxication mechanism. Further experimental investigations should address this newly detected activity to identify catalytic residues and elucidate the molecular mechanism responsible for this action.
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Affiliation(s)
- Marta Borowiec
- Laboratory of Bioinformatics and Systems Biology, Centre of New Technologies, University of Warsaw, Zwirki i Wigury 93, Warsaw 02-089, Poland.
| | - Michal Gorzkiewicz
- Laboratory of Cellular Immunology, Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, Lodz 93-232, Poland.
| | - Joanna Grzesik
- Laboratory of Bioinformatics and Systems Biology, Centre of New Technologies, University of Warsaw, Zwirki i Wigury 93, Warsaw 02-089, Poland.
| | - Aurelia Walczak-Drzewiecka
- Laboratory of Cellular Immunology, Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, Lodz 93-232, Poland.
| | - Anna Salkowska
- Laboratory of Cellular Immunology, Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, Lodz 93-232, Poland.
| | | | - Kamil Steczkiewicz
- Laboratory of Bioinformatics and Systems Biology, Centre of New Technologies, University of Warsaw, Zwirki i Wigury 93, Warsaw 02-089, Poland.
| | - Leszek Rychlewski
- BioInfoBank Institute, Sw. Marcin 80/82 r.355, Poznan 61-809, Poland.
| | - Jaroslaw Dastych
- Laboratory of Cellular Immunology, Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, Lodz 93-232, Poland.
| | - Krzysztof Ginalski
- Laboratory of Bioinformatics and Systems Biology, Centre of New Technologies, University of Warsaw, Zwirki i Wigury 93, Warsaw 02-089, Poland.
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15
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Silva DS, Pereira LMG, Moreira AR, Ferreira-da-Silva F, Brito RM, Faria TQ, Zornetta I, Montecucco C, Oliveira P, Azevedo JE, Pereira PJB, Macedo-Ribeiro S, do Vale A, dos Santos NMS. The apoptogenic toxin AIP56 is a metalloprotease A-B toxin that cleaves NF-κb P65. PLoS Pathog 2013; 9:e1003128. [PMID: 23468618 PMCID: PMC3585134 DOI: 10.1371/journal.ppat.1003128] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 11/28/2012] [Indexed: 12/15/2022] Open
Abstract
AIP56 (apoptosis-inducing protein of 56 kDa) is a major virulence factor of Photobacterium damselae piscicida (Phdp), a Gram-negative pathogen that causes septicemic infections, which are among the most threatening diseases in mariculture. The toxin triggers apoptosis of host macrophages and neutrophils through a process that, in vivo, culminates with secondary necrosis of the apoptotic cells contributing to the necrotic lesions observed in the diseased animals. Here, we show that AIP56 is a NF-κB p65-cleaving zinc-metalloprotease whose catalytic activity is required for the apoptogenic effect. Most of the bacterial effectors known to target NF-κB are type III secreted effectors. In contrast, we demonstrate that AIP56 is an A-B toxin capable of acting at distance, without requiring contact of the bacteria with the target cell. We also show that the N-terminal domain cleaves NF-κB at the Cys39-Glu40 peptide bond and that the C-terminal domain is involved in binding and internalization into the cytosol. The apoptosis inducing protein of 56 kDa (AIP56) is a key virulence factor secreted by Photobacterium damselae piscicida (Phdp), a Gram-negative bacterium that causes septicaemic infections in economically important marine fish species. It is known that AIP56 induces massive destruction of the phagocytic cells of the infected host, allowing the extracellular multiplication of the bacteria and contributing to the genesis of the pathology. Here we show that AIP56 acts by cleaving NF-κB p65. The NF-κB family of transcription factors is evolutionarily conserved and plays a central role in the host responses to microbial pathogen invasion, regulating the expression of inflammatory and anti-apoptotic genes. Pathogenic bacteria have evolved complex strategies to interfere with NF-κB signalling, usually by injecting protein effectors directly into the cell's cytosol through bacterial secretion machineries that require contact with host cells. In contrast, AIP56 acts at distance and has an intrinsic ability to reach the cytosol due to the presence of a C-terminal domain that functions as “delivery module.”
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Affiliation(s)
- Daniela S. Silva
- Fish Immunology and Vaccinology, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Liliana M. G. Pereira
- Fish Immunology and Vaccinology, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Ana R. Moreira
- Fish Immunology and Vaccinology, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Frederico Ferreira-da-Silva
- Protein Production and Purification, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Rui M. Brito
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
- Chemistry Department, Faculty of Science and Technology, University of Coimbra, Coimbra, Portugal
| | - Tiago Q. Faria
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
| | - Irene Zornetta
- Dipartimento di Scienze Biomediche dell'Università di Padova and Instituto di Neuroscienze del CNR, Padova, Italy
| | - Cesare Montecucco
- Dipartimento di Scienze Biomediche dell'Università di Padova and Instituto di Neuroscienze del CNR, Padova, Italy
| | - Pedro Oliveira
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Jorge E. Azevedo
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
- Organelle Biogenesis and Function, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Pedro J. B. Pereira
- Biomolecular Structure, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Sandra Macedo-Ribeiro
- Protein Crystallography, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Ana do Vale
- Fish Immunology and Vaccinology, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Nuno M. S. dos Santos
- Fish Immunology and Vaccinology, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- * E-mail:
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16
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Weldon JE, Xiang L, Zhang J, Beers R, Walker DA, Onda M, Hassan R, Pastan I. A recombinant immunotoxin against the tumor-associated antigen mesothelin reengineered for high activity, low off-target toxicity, and reduced antigenicity. Mol Cancer Ther 2012; 12:48-57. [PMID: 23136186 DOI: 10.1158/1535-7163.mct-12-0336] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
SS1P is a recombinant immunotoxin (RIT) engineered for the targeted elimination of malignant cells that express the tumor-associated antigen mesothelin. It is composed of an antimesothelin antibody variable fragment (Fv) linked to a cytotoxic fragment of Pseudomonas exotoxin A (PE) that includes domains II and III of native PE. The clinical use of SS1P is limited by its propensity to induce neutralizing antibodies and to cause a dose-limiting capillary leak syndrome (CLS) in patients. In this article, we describe a reengineered SS1P with improved properties that overcome these deficits. The redesign of SS1P consists of (i) removing the bulk of PE domain II (residues 251-273 and 284-394 of native PE), leaving only an 11-residue furin cleavage site, (ii) adding a Gly-Gly-Ser peptide linker after the furin cleavage site, and (iii) replacing eight highly solvent-exposed residues in the catalytic domain of PE. The new molecule, SS1-LR/GGS/8M, has cytotoxic activity comparable with SS1P on several mesothelin-expressing cell lines and remarkably improved activity on primary cells from patients with mesothelioma. In a mouse xenograft tumor model, high doses of SS1-LR/GGS/8M elicit antitumor activity superior to the activity of SS1P at its maximum-tolerated dose. In addition, SS1-LR/GGS/8M has greatly decreased ability to cause CLS in a rat model and reduced antigenicity or reactivity with antibodies to the sera of patients previously treated with SS1P.
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Affiliation(s)
- John E Weldon
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
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17
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Fieldhouse RJ, Jørgensen R, Lugo MR, Merrill AR. The 1.8 Å cholix toxin crystal structure in complex with NAD+ and evidence for a new kinetic model. J Biol Chem 2012; 287:21176-88. [PMID: 22535961 DOI: 10.1074/jbc.m111.337311] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Certain Vibrio cholerae strains produce cholix, a potent protein toxin that has diphthamide-specific ADP-ribosyltransferase activity against eukaryotic elongation factor 2. Here we present a 1.8 Å crystal structure of cholix in complex with its natural substrate, nicotinamide adenine dinucleotide (NAD(+)). We also substituted hallmark catalytic residues by site-directed mutagenesis and analyzed both NAD(+) binding and ADP-ribosyltransferase activity using a fluorescence-based assay. These data are the basis for a new kinetic model of cholix toxin activity. Further, the new structural data serve as a reference for continuing inhibitor development for this toxin class.
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Affiliation(s)
- Robert J Fieldhouse
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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18
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Pasetto M, Barison E, Castagna M, Della Cristina P, Anselmi C, Colombatti M. Reductive activation of type 2 ribosome-inactivating proteins is promoted by transmembrane thioredoxin-related protein. J Biol Chem 2012; 287:7367-73. [PMID: 22228764 PMCID: PMC3293526 DOI: 10.1074/jbc.m111.316828] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 12/21/2011] [Indexed: 11/06/2022] Open
Abstract
Members of the type 2 ribosome-inactivating proteins (RIPs) family (e.g. ricin, abrin) are potent cytotoxins showing a strong lethal activity toward eukaryotic cells. Type 2 RIPs contain two polypeptide chains (usually named A, for "activity", and B, for "binding") linked by a disulfide bond. The intoxication of the cell is a consequence of a reductive process in which the toxic domain is cleaved from the binding domain by oxidoreductases located in the lumen of the endoplasmic reticulum (ER). The best known example of type 2 RIPs is ricin. Protein disulfide isomerase (PDI) was demonstrated to be involved in the process of ricin reduction; however, when PDI is depleted from cell fraction preparations ricin reduction can still take place, indicating that also other oxidoreductases might be implicated in this process. We have investigated the role of TMX, a transmembrane thioredoxin-related protein member of the PDI family, in the cell intoxication operated by type 2 RIPs ricin and abrin. Overexpressing TMX in A549 cells resulted in a dramatic increase of ricin or abrin cytotoxicity compared with control mock-treated cells. Conversely, no difference in cytotoxicity was observed after treatment of A549 cells or control cells with saporin or Pseudomonas exotoxin A whose intracellular mechanism of activation is not dependent upon reduction (saporin) or only partially dependent upon it (Pseudomonas exotoxin A). Moreover, the silencing of TMX in the prostatic cell line DU145 reduced the sensitivity of the cells to ricin intoxication further confirming a role for this enzyme in intracellular ricin activation.
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Affiliation(s)
- Matteo Pasetto
- Department of Pathology and Diagnostics, Section of Immunology, University of Verona, Policlinico G. B. Rossi, P. le L. Scuro 10, 37134 Verona, Italy.
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19
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Méré J, Chopard C, Bonhoure A, Morlon-Guyot J, Beaumelle B. Increasing stability and toxicity of Pseudomonas exotoxin by attaching an antiproteasic Peptide. Biochemistry 2011; 50:10052-60. [PMID: 22014283 DOI: 10.1021/bi2010009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Trypsin-like activities are present within the endocytic pathway and allow cells to inactivate a fraction of incoming toxins, such as Pseudomonas exotoxin (PE), that require endocytic uptake before reaching the cytosol to inactivate protein synthesis. PE is a favorite toxin for building immunotoxins. The latter are promising molecules to fight cancer or transplant rejection, and producing more active toxins is a key challenge. More broadly, increasing protein stability is a potentially useful approach to improve the efficiency of therapeutic proteins. We report here that fusing an antiproteasic peptide (bovine pancreatic trypsin inhibitor, BPTI) to PE increases its toxicity to human cancer cell lines by 20-40-fold. Confocal microscopic examination of toxin endocytosis, digestion, and immunoprecipitation experiments showed that the fused antiproteasic peptide specifically protects PE from trypsin-like activities. Hence, the attached BPTI acts as a bodyguard for the toxin within the endocytic pathway. Moreover, it increased the PE elimination half-time in mice by 70%, indicating that the fused BPTI stabilizes the toxin in vivo. This BPTI-fusion approach may be useful for protecting other circulating or internalized proteins of therapeutic interest from premature degradation.
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Affiliation(s)
- Jocelyn Méré
- CPBS, UMR 5236 CNRS, 1919 route de Mende, 34293 Montpellier, France
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20
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El Hage T, Lorin S, Decottignies P, Djavaheri-Mergny M, Authier F. Proteolysis of Pseudomonas exotoxin A within hepatic endosomes by cathepsins B and D produces fragments displaying in vitro ADP-ribosylating and apoptotic effects. FEBS J 2010; 277:3735-49. [PMID: 20718861 DOI: 10.1111/j.1742-4658.2010.07775.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To assess Pseudomonas exotoxin A (ETA) compartmentalization, processing and cytotoxicity in vivo, we have studied the fate of internalized ETA with the use of the in vivo rodent liver model following toxin administration, cell-free hepatic endosomes, and pure in vitro protease assays. ETA taken up into rat liver in vivo was rapidly associated with plasma membranes (5-30 min), internalized within endosomes (15-60 min), and later translocated into the cytosolic compartment (30-90 min). Coincident with endocytosis of intact ETA, in vivo association of the catalytic ETA-A subunit and low molecular mass ETA-A fragments was observed in the endosomal apparatus. After an in vitro proteolytic assay with an endosomal lysate and pure proteases, the ETA-degrading activity was attributed to the luminal species of endosomal acidic cathepsins B and D, with the major cleavages generated in vitro occurring mainly within domain III of ETA-A. Cell-free endosomes preloaded in vivo with ETA intraluminally processed and extraluminally released intact ETA and ETA-A in vitro in a pH-dependent and ATP-dependent manner. Rat hepatic cells underwent in vivo intrinsic apoptosis at a late stage of ETA infection, as assessed by the mitochondrial release of cytochrome c, caspase-9 and caspase-3 activation, and DNA fragmentation. In an in vitro assay, intact ETA induced ADP-ribosylation of EF-2 and mitochondrial release of cytochrome c, with the former effect being efficiently increased by a cathepsin B/cathepsin D pretreatment. The data show a novel processing pathway for internalized ETA, involving cathepsins B and D, resulting in the production of ETA fragments that may participate in cytotoxicity and mitochondrial dysfunction.
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21
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Abstract
Lung infections caused by the opportunistic pathogen Pseudomonas aeruginosa can present as a spectrum of clinical entities from a rapidly fatal pneumonia in a neutropenic patient to a multi-decade bronchitis in patients with cystic fibrosis. P. aeruginosa is ubiquitous in our environment, and one of the most versatile pathogens studied, capable of infecting a number of diverse life forms and surviving harsh environmental factors. It is also able to quickly adapt to new environments, including the lung, where it orchestrates virulence factors to acquire necessary nutrients, and if necessary, turn them off to prevent immune recognition. Despite these capabilities, P. aeruginosa rarely infects healthy human lungs. This is secondary to a highly evolved host defence mechanism that efficiently removes inhaled or aspirated pseudomonads. Many arms of the respiratory host defence have been elucidated using P. aeruginosa as a model pathogen. Human infections with P. aeruginosa have demonstrated the importance of the mechanical barrier functions including mucus clearance, and the innate immune system, including the critical role of the neutrophilic response. As more models of persistent or biofilm P. aeruginosa infections are developed, the role of the adaptive immune response will likely become more evident. Understanding the pathogenesis of P. aeruginosa, and the respiratory host defence response to it has, and will continue to, lead to novel therapeutic strategies to help patients.
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Affiliation(s)
- Bryan J Williams
- Pulmonary, Allergy, Critical Care and Sleep Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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