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Shyam M, Kumar S, Singh V. Unlocking Opportunities for Mycobacterium leprae and Mycobacterium ulcerans. ACS Infect Dis 2024; 10:251-269. [PMID: 38295025 PMCID: PMC10862552 DOI: 10.1021/acsinfecdis.3c00371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 12/25/2023] [Accepted: 12/28/2023] [Indexed: 02/02/2024]
Abstract
In the recent decade, scientific communities have toiled to tackle the emerging burden of drug-resistant tuberculosis (DR-TB) and rapidly growing opportunistic nontuberculous mycobacteria (NTM). Among these, two neglected mycobacteria species of the Acinetobacter family, Mycobacterium leprae and Mycobacterium ulcerans, are the etiological agents of leprosy and Buruli ulcer infections, respectively, and fall under the broad umbrella of neglected tropical diseases (NTDs). Unfortunately, lackluster drug discovery efforts have been made against these pathogenic bacteria in the recent decade, resulting in the discovery of only a few countable hits and majorly repurposing anti-TB drug candidates such as telacebec (Q203), P218, and TB47 for current therapeutic interventions. Major ignorance in drug candidate identification might aggravate the dramatic consequences of rapidly spreading mycobacterial NTDs in the coming days. Therefore, this Review focuses on an up-to-date account of drug discovery efforts targeting selected druggable targets from both bacilli, including the accompanying challenges that have been identified and are responsible for the slow drug discovery. Furthermore, a succinct discussion of the all-new possibilities that could be alternative solutions to mitigate the neglected mycobacterial NTD burden and subsequently accelerate the drug discovery effort is also included. We anticipate that the state-of-the-art strategies discussed here may attract major attention from the scientific community to navigate and expand the roadmap for the discovery of next-generation therapeutics against these NTDs.
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Affiliation(s)
- Mousumi Shyam
- Department
of Pharmaceutical Sciences & Technology, Birla Institute of Technology, Mersa, Ranchi, Jharkhand 835215, India
| | - Sumit Kumar
- Holistic
Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch 7701, South Africa
| | - Vinayak Singh
- Holistic
Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch 7701, South Africa
- South
African Medical Research Council Drug Discovery and Development Research
Unit, University of Cape Town, Rondebosch 7701, South Africa
- Institute
of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Observatory 7925, Cape Town, South Africa
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2
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Chavda VP, Haritopoulou-Sinanidou M, Bezbaruah R, Apostolopoulos V. Vaccination efforts for Buruli Ulcer. Expert Rev Vaccines 2022; 21:1419-1428. [PMID: 35962475 DOI: 10.1080/14760584.2022.2113514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Buruli ulcer is one of the most common mycobacterial diseases usually affecting poorer populations in tropical and subtropical environments. This disease, caused by M. ulcerans infection, has devastating effects for patients, with significant health and economic burden. Antibiotics are often used to treat affected individuals, but in most cases, surgery is necessary. AREA COVERED We present progress on Buruli ulcer vaccines and identify knowledge gaps in this neglected tropical disease. EXPERT OPINION The lack of appropriate infrastructure in endemic areas, as well as the severity of symptoms and lack of non-invasive treatment options, highlights the need for an effective vaccine to combat this disease. In terms of humoral immunity, it is vital to consider its significance and the magnitude to which it inhibits or slowdowns the progression of the disease. Only by answering these key questions will it be possible to tailor more appropriate vaccination and preventative provisions.
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Affiliation(s)
- Vivek P Chavda
- Department of Pharmaceutics and Pharmaceutical Technology, L M College of Pharmacy, Ahmedabad, India
| | | | - Rajashri Bezbaruah
- Department of Pharmaceutical Sciences, Faculty of Science and Engineering, Dibrugarh University, Dibrugarh, Assam, India
| | - Vasso Apostolopoulos
- Institute for Health and Sport, Immunology and Translational Research Group, Victoria University, Melbourne VIC, Australia.,Australian Institute for Musculoskeletal Science (AIMSS), Immunology Program, Melbourne VIC, Australia
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3
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Hall BS, Hsieh LTH, Sacre S, Simmonds RE. The One That Got Away: How Macrophage-Derived IL-1β Escapes the Mycolactone-Dependent Sec61 Blockade in Buruli Ulcer. Front Immunol 2022; 12:788146. [PMID: 35154073 PMCID: PMC8826060 DOI: 10.3389/fimmu.2021.788146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/27/2021] [Indexed: 11/13/2022] Open
Abstract
Buruli ulcer (BU), caused by Mycobacterium ulcerans, is a devastating necrotizing skin disease. Key to its pathogenesis is mycolactone, the exotoxin virulence factor that is both immunosuppressive and cytotoxic. The discovery that the essential Sec61 translocon is the major cellular target of mycolactone explains much of the disease pathology, including the immune blockade. Sec61 inhibition leads to a loss in production of nearly all cytokines from monocytes, macrophages, dendritic cells and T cells, as well as antigen presentation pathway proteins and costimulatory molecules. However, there has long been evidence that the immune system is not completely incapable of responding to M. ulcerans infection. In particular, IL-1β was recently shown to be present in BU lesions, and to be induced from M. ulcerans-exposed macrophages in a mycolactone-dependent manner. This has important implications for our understanding of BU, showing that mycolactone can act as the "second signal" for IL-1β production without inhibiting the pathways of unconventional secretion it uses for cellular release. In this Perspective article, we validate and discuss this recent advance, which is entirely in-line with our understanding of mycolactone's inhibition of the Sec61 translocon. However, we also show that the IL-1 receptor, which uses the conventional secretory pathway, is sensitive to mycolactone blockade at Sec61. Hence, a more complete understanding of the mechanisms regulating IL-1β function in skin tissue, including the transient intra-macrophage stage of M. ulcerans infection, is urgently needed to uncover the double-edged sword of IL-1β in BU pathogenesis, treatment and wound healing.
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Affiliation(s)
- Belinda S Hall
- Department of Microbial Sciences, School of Bioscience and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Louise Tzung-Harn Hsieh
- Department of Microbial Sciences, School of Bioscience and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Sandra Sacre
- Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
| | - Rachel E Simmonds
- Department of Microbial Sciences, School of Bioscience and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
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4
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Muhi S, Stinear TP. Systematic review of M. Bovis BCG and other candidate vaccines for Buruli ulcer prophylaxis. Vaccine 2021; 39:7238-7252. [PMID: 34119347 DOI: 10.1016/j.vaccine.2021.05.092] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/10/2021] [Accepted: 05/23/2021] [Indexed: 01/17/2023]
Abstract
Buruli ulcer, caused by Mycobacterium ulcerans, is a neglected tropical disease endemic to over 30 countries, with increasing incidence in temperate, coastal Victoria, Australia. Strategies to control transmission are urgently required. This study systematically reviews the literature to identify and describe candidate prophylactic Buruli ulcer vaccines. This review highlights that Mycobacterium bovis Bacillus Calmette-Guérin (BCG) vaccine is the only vaccine studied in randomised controlled trials and confirms its importance as a benchmark for comparison against putative vaccines in pre-clinical studies. Nevertheless, BCG alone is unable to offer long-term protection in humans. A number of experimental vaccines that exceed the protection provided by BCG in mice have emerged, particularly those utilising recombinant BCG expressing immunogenic M. ulcerans proteins. Although progress is promising, there remain key questions about the optimal approach to characterising the immunological correlates of protection in humans and strategies to investigate the safety and efficacy of such vaccines in humans.
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Affiliation(s)
- Stephen Muhi
- Victorian Infectious Diseases Service at the Royal Melbourne Hospital, Melbourne, Australia; Department of Microbiology and Immunology, Peter Doherty Institute at the University of Melbourne, Melbourne, Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, Peter Doherty Institute at the University of Melbourne, Melbourne, Australia.
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5
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Demangel C. Immunity against Mycobacterium ulcerans: The subversive role of mycolactone. Immunol Rev 2021; 301:209-221. [PMID: 33607704 DOI: 10.1111/imr.12956] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/19/2021] [Accepted: 01/19/2021] [Indexed: 12/11/2022]
Abstract
Mycobacterium ulcerans causes Buruli ulcer, a neglected tropical skin disease manifesting as chronic wounds that can leave victims with major, life-long deformity and disability. Differently from other mycobacterial pathogens, M ulcerans produces mycolactone, a diffusible lipid factor with unique cytotoxic and immunomodulatory properties. Both traits result from mycolactone targeting Sec61, the entry point of the secretory pathway in eukaryotic cells. By inhibiting Sec61, mycolactone prevents the host cell's production of secreted proteins, and most of its transmembrane proteins. This molecular blockade dramatically alters the functions of immune cells, thereby the generation of protective immunity. Moreover, sustained inhibition of Sec61 triggers proteotoxic stress responses leading to apoptotic cell death, which can stimulate vigorous immune responses. The dynamics of bacterial production of mycolactone and elimination by infected hosts thus critically determine the balance between its immunostimulatory and immunosuppressive effects. Following an introduction summarizing the essential information on Buruli ulcer disease, this review focuses on the current state of knowledge regarding mycolactone's regulation and biodistribution. We then detail the consequences of mycolactone-mediated Sec61 blockade on initiation and maintenance of innate and adaptive immune responses. Finally, we discuss the key questions to address in order to improve immunity to M ulcerans, and how increased knowledge of mycolactone biology may pave the way to innovative therapeutics.
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Affiliation(s)
- Caroline Demangel
- Immunobiology of Infection Unit, INSERM U1221, Institut Pasteur, Paris, France
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Van Der Werf TS, Barogui YT, Converse PJ, Phillips RO, Stienstra Y. Pharmacologic management of Mycobacterium ulcerans infection. Expert Rev Clin Pharmacol 2020; 13:391-401. [PMID: 32310683 DOI: 10.1080/17512433.2020.1752663] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Pharmacological treatment of Buruli ulcer (Mycobacterium ulcerans infection; BU) is highly effective, as shown in two randomized trials in Africa. AREAS COVERED We review BU drug treatment - in vitro, in vivo and clinical trials (PubMed: '(Buruli OR (Mycobacterium AND ulcerans)) AND (treatment OR therapy).' We also highlight the pathogenesis of M. ulcerans infection that is dominated by mycolactone, a secreted exotoxin, that causes skin and soft tissue necrosis, and impaired immune response and tissue repair. Healing is slow, due to the delayed wash-out of mycolactone. An array of repurposed tuberculosis and leprosy drugs appears effective in vitro and in animal models. In clinical trials and observational studies, only rifamycins (notably, rifampicin), macrolides (notably, clarithromycin), aminoglycosides (notably, streptomycin) and fluoroquinolones (notably, moxifloxacin, and ciprofloxacin) have been tested. EXPERT OPINION A combination of rifampicin and clarithromycin is highly effective but lesions still take a long time to heal. Novel drugs like telacebec have the potential to reduce treatment duration but this drug may remain unaffordable in low-resourced settings. Research should address ulcer treatment in general; essays to measure mycolactone over time hold promise to use as a readout for studies to compare drug treatment schedules for larger lesions of Buruli ulcer.
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Affiliation(s)
- Tjip S Van Der Werf
- Departments of Internal Medicine/Infectious Diseases, University Medical Centre Groningen, University of Groningen , Groningen, Netherlands.,Pulmonary Diseases & Tuberculosis, University Medical Centre Groningen, University of Groningen , Groningen, Netherlands
| | - Yves T Barogui
- Ministère De La Sante ́, Programme National Lutte Contre La Lèpre Et l'Ulcère De Buruli , Cotonou, Benin
| | - Paul J Converse
- Department of Medicine, Johns Hopkins University Center for Tuberculosis Research , Baltimore, Maryland, USA
| | - Richard O Phillips
- Kumasi, Ghana And Kwame Nkrumah University of Science and Technology, Komfo Anokye Teaching Hospital , Kumasi, Ghana
| | - Ymkje Stienstra
- Departments of Internal Medicine/Infectious Diseases, University Medical Centre Groningen, University of Groningen , Groningen, Netherlands
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Vaccine-Specific Immune Responses against Mycobacterium ulcerans Infection in a Low-Dose Murine Challenge Model. Infect Immun 2020; 88:IAI.00753-19. [PMID: 31818964 DOI: 10.1128/iai.00753-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/06/2019] [Indexed: 01/22/2023] Open
Abstract
The neglected tropical disease Buruli ulcer (BU) is an infection of subcutaneous tissue with Mycobacterium ulcerans There is no effective vaccine. Here, we assessed an experimental prime-boost vaccine in a low-dose murine tail infection model. We used the enoyl reductase (ER) domain of the M. ulcerans mycolactone polyketide synthases electrostatically coupled with a previously described Toll-like receptor 2 (TLR-2) agonist-based lipopeptide adjuvant, R4Pam2Cys. Mice were vaccinated and then challenged via tail inoculation with 14 to 20 CFU of a bioluminescent strain of M. ulcerans Mice receiving either the experimental ER vaccine or Mycobacterium bovis bacillus Calmette-Guérin (BCG) were equally protected, with both groups faring significantly better than nonvaccinated animals (P < 0.05). To explore potential correlates of protection, a suite of 29 immune parameters were assessed in the mice at the end of the experimental period. Multivariate statistical approaches were used to interrogate the immune response data to develop disease-prognostic models. High levels of interleukin 2 (IL-2) and low gamma interferon (IFN-γ) produced in the spleen best predicted control of infection across all vaccine groups. Univariate logistic regression revealed vaccine-specific profiles of protection. High titers of ER-specific IgG serum antibodies together with IL-2 and IL-4 in the draining lymph node (DLN) were associated with protection induced by the ER vaccine. In contrast, high titers of IL-6, tumor necrosis factor alpha (TNF-α), IFN-γ, and IL-10 in the DLN and low IFN-γ titers in the spleen were associated with protection following BCG vaccination. This study suggests that an effective BU vaccine must induce localized, tissue-specific immune profiles with controlled inflammatory responses at the site of infection.
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Reynaert ML, Dupoiron D, Yeramian E, Marsollier L, Brodin P. Could Mycolactone Inspire New Potent Analgesics? Perspectives and Pitfalls. Toxins (Basel) 2019; 11:toxins11090516. [PMID: 31487908 PMCID: PMC6783859 DOI: 10.3390/toxins11090516] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 08/26/2019] [Accepted: 09/03/2019] [Indexed: 12/20/2022] Open
Abstract
Pain currently represents the most common symptom for which medical attention is sought by patients. The available treatments have limited effectiveness and significant side-effects. In addition, most often, the duration of analgesia is short. Today, the handling of pain remains a major challenge. One promising alternative for the discovery of novel potent analgesics is to take inspiration from Mother Nature; in this context, the detailed investigation of the intriguing analgesia implemented in Buruli ulcer, an infectious disease caused by the bacterium Mycobacterium ulcerans and characterized by painless ulcerative lesions, seems particularly promising. More precisely, in this disease, the painless skin ulcers are caused by mycolactone, a polyketide lactone exotoxin. In fact, mycolactone exerts a wide range of effects on the host, besides being responsible for analgesia, as it has been shown notably to modulate the immune response or to provoke apoptosis. Several cellular mechanisms and different targets have been proposed to account for the analgesic effect of the toxin, such as nerve degeneration, the inhibition of inflammatory mediators and the activation of angiotensin II receptor 2. In this review, we discuss the current knowledge in the field, highlighting possible controversies. We first discuss the different pain-mimicking experimental models that were used to study the effect of mycolactone. We then detail the different variants of mycolactone that were used in such models. Overall, based on the results and the discussions, we conclude that the development of mycolactone-derived molecules can represent very promising perspectives for new analgesic drugs, which could be effective for specific pain indications.
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Affiliation(s)
- Marie-Line Reynaert
- France Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR8204-CIIL-Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Denis Dupoiron
- Institut de Cancérologie de l'Ouest Paul Papin, 15 rue André Boquel-49055 Angers, France
| | - Edouard Yeramian
- Unité de Microbiologie Structurale, Institut Pasteur, CNRS, Univ. Paris, F-75015 Paris, France
| | - Laurent Marsollier
- Equipe ATIP AVENIR, CRCINA, INSERM, Univ. Nantes, Univ. Angers, 4 rue Larrey, F-49933 Angers, France.
| | - Priscille Brodin
- France Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR8204-CIIL-Center for Infection and Immunity of Lille, F-59000 Lille, France.
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9
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Loglo AD, Frimpong M, Sarpong Duah M, Sarfo F, Sarpong FN, Agbavor B, Boakye-Appiah JK, Abass KM, Dongyele M, Frempong M, Pidot S, Wansbrough-Jones M, Stinear TP, Roupie V, Huygen K, Phillips RO. IFN-γ and IL-5 whole blood response directed against mycolactone polyketide synthase domains in patients with Mycobacterium ulcerans infection. PeerJ 2018; 6:e5294. [PMID: 30090691 PMCID: PMC6078848 DOI: 10.7717/peerj.5294] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 07/02/2018] [Indexed: 01/04/2023] Open
Abstract
Background Buruli ulcer is a disease of the skin and soft tissues caused by infection with a slow growing pathogen, Mycobacterium ulcerans. A vaccine for this disease is not available but M. ulcerans possesses a giant plasmid pMUM001 that harbours the polyketide synthase (PKS) genes encoding a multi-enzyme complex needed for the production of its unique lipid toxin called mycolactone, which is central to the pathogenesis of Buruli ulcer. We have studied the immunogenicity of enzymatic domains in humans with M. ulcerans disease, their contacts, as well as non-endemic areas controls. Methods Between March 2013 and August 2015, heparinized whole blood was obtained from patients confirmed with Buruli ulcer. The blood samples were diluted 1 in 10 in Roswell Park Memorial Institute (RPMI) medium and incubated for 5 days with recombinant mycolactone PKS domains and mycolyltransferase antigen 85A (Ag85A). Blood samples were obtained before and at completion of antibiotic treatment for 8 weeks and again 8 weeks after completion of treatment. Supernatants were assayed for interferon-γ (IFN-γ) and interleukin-5 (IL-5) by enzyme-linked immunosorbent assay. Responses were compared with those of contacts and non-endemic controls. Results More than 80% of patients and contacts from endemic areas produced IFN-γ in response to all the antigens except acyl carrier protein type 3 (ACP3) to which only 47% of active Buruli ulcer cases and 71% of contacts responded. The highest proportion of responders in cases and contacts was to load module ketosynthase domain (Ksalt) (100%) and enoylreductase (100%). Lower IL-5 responses were induced in a smaller proportion of patients ranging from 54% after ketoreductase type B stimulation to only 21% with ketosynthase type C (KS C). Among endemic area contacts, the, highest proportion was 73% responding to KS C and the lowest was 40% responding to acyltransferase with acetate specificity type 2. Contacts of Buruli ulcer patients produced significantly higher IFN-γ and IL-5 responses compared with those of patients to PKS domain antigens and to mycolyltransferase Ag85A of M. ulcerans. There was low or no response to all the antigens in non-endemic areas controls. IFN-γ and IL-5 responses of patients improved after treatment when compared to baseline results. Discussion The major response to PKS antigen stimulation was IFN-γ and the strongest responses were observed in healthy contacts of patients living in areas endemic for Buruli ulcer. Patients elicited lower responses than healthy contacts, possibly due to the immunosuppressive effect of mycolactone, but the responses were enhanced after antibiotic treatment. A vaccine made up of the most immunogenic PKS domains combined with the mycolyltransferase Ag85A warrants further investigation.
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Affiliation(s)
- Aloysius D Loglo
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Michael Frimpong
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Mabel Sarpong Duah
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Fred Sarfo
- School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Francisca N Sarpong
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Bernadette Agbavor
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | | | | | | | - Margaret Frempong
- School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Sacha Pidot
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| | | | - Timothy P Stinear
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| | - Virginie Roupie
- Service Immunology, Scientific Institute of Public Health, Brussels, Belgium
| | - Kris Huygen
- Service Immunology, Scientific Institute of Public Health, Brussels, Belgium
| | - Richard O Phillips
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.,School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
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10
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Sarfo FS, Phillips R, Wansbrough-Jones M, Simmonds RE. Recent advances: role of mycolactone in the pathogenesis and monitoring of Mycobacterium ulcerans infection/Buruli ulcer disease. Cell Microbiol 2016; 18:17-29. [PMID: 26572803 PMCID: PMC4705457 DOI: 10.1111/cmi.12547] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 11/10/2015] [Accepted: 11/13/2015] [Indexed: 02/03/2023]
Abstract
Infection of subcutaneous tissue with Mycobacterium ulcerans can lead to chronic skin ulceration known as Buruli ulcer. The pathogenesis of this neglected tropical disease is dependent on a lipid‐like toxin, mycolactone, which diffuses through tissue away from the infecting organisms. Since its identification in 1999, this molecule has been intensely studied to elucidate its cytotoxic and immunosuppressive properties. Two recent major advances identifying the underlying molecular targets for mycolactone have been described. First, it can target scaffolding proteins (such as Wiskott Aldrich Syndrome Protein), which control actin dynamics in adherent cells and therefore lead to detachment and cell death by anoikis. Second, it prevents the co‐translational translocation (and therefore production) of many proteins that pass through the endoplasmic reticulum for secretion or placement in cell membranes. These pleiotropic effects underpin the range of cell‐specific functional defects in immune and other cells that contact mycolactone during infection. The dose and duration of mycolactone exposure for these different cells explains tissue necrosis and the paucity of immune cells in the ulcers. This review discusses recent advances in the field, revisits older findings in this context and highlights current developments in structure‐function studies as well as methodology that make mycolactone a promising diagnostic biomarker.
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Affiliation(s)
- Fred Stephen Sarfo
- Department of Medicine, Kwame Nkrumah University of Science & Technology, Kumasi, Ghana
| | - Richard Phillips
- Department of Medicine, Kwame Nkrumah University of Science & Technology, Kumasi, Ghana
| | - Mark Wansbrough-Jones
- Division of Cellular and Molecular Medicine, St George's, University of London, London, UK
| | - Rachel E Simmonds
- School of Biosciences and Medicine, University of Surrey, Guildford, UK
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11
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Murphy AC, Hong H, Vance S, Broadhurst RW, Leadlay PF. Broadening substrate specificity of a chain-extending ketosynthase through a single active-site mutation. Chem Commun (Camb) 2016; 52:8373-6. [DOI: 10.1039/c6cc03501a] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An in vitro model system based on a ketosynthase domain of the erythromycin polyketide synthase was used to probe the apparent substrate tolerance of ketosynthase domains of the mycolactone polyketide synthase.
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Affiliation(s)
- Annabel C. Murphy
- Department of Biochemistry
- University of Cambridge
- Cambridge CB2 1GA
- UK
| | - Hui Hong
- Department of Biochemistry
- University of Cambridge
- Cambridge CB2 1GA
- UK
| | - Steve Vance
- Department of Biochemistry
- University of Cambridge
- Cambridge CB2 1GA
- UK
- Crescendo Biologics Ltd
| | | | - Peter F. Leadlay
- Department of Biochemistry
- University of Cambridge
- Cambridge CB2 1GA
- UK
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12
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The LINKS motif zippers trans-acyltransferase polyketide synthase assembly lines into a biosynthetic megacomplex. J Struct Biol 2015; 193:196-205. [PMID: 26724270 DOI: 10.1016/j.jsb.2015.12.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 12/04/2015] [Accepted: 12/22/2015] [Indexed: 11/21/2022]
Abstract
Polyketides such as the clinically-valuable antibacterial agent mupirocin are constructed by architecturally-sophisticated assembly lines known as trans-acyltransferase polyketide synthases. Organelle-sized megacomplexes composed of several copies of trans-acyltransferase polyketide synthase assembly lines have been observed by others through transmission electron microscopy to be located at the Bacillus subtilis plasma membrane, where the synthesis and export of the antibacterial polyketide bacillaene takes place. In this work we analyze ten crystal structures of trans-acyltransferase polyketide synthases ketosynthase domains, seven of which are reported here for the first time, to characterize a motif capable of zippering assembly lines into a megacomplex. While each of the three-helix LINKS (Laterally-INteracting Ketosynthase Sequence) motifs is observed to similarly dock with a spatially-reversed copy of itself through hydrophobic and ionic interactions, the amino acid sequences of this motif are not conserved. Such a code is appropriate for mediating homotypic contacts between assembly lines to ensure the ordered self-assembly of a noncovalent, yet tightly-knit, enzymatic network. LINKS-mediated lateral interactions would also have the effect of bolstering the vertical association of the polypeptides that comprise a polyketide synthase assembly line.
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13
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Quadri LEN. Biosynthesis of mycobacterial lipids by polyketide synthases and beyond. Crit Rev Biochem Mol Biol 2014; 49:179-211. [DOI: 10.3109/10409238.2014.896859] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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14
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Chany AC, Tresse C, Casarotto V, Blanchard N. History, biology and chemistry of Mycobacterium ulcerans infections (Buruli ulcer disease). Nat Prod Rep 2014; 30:1527-67. [PMID: 24178858 DOI: 10.1039/c3np70068b] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mycobacterium ulcerans infections (Buruli ulcer disease) have a long history that can be traced back 150 years. The successive discoveries of the mycobacteria in 1948 and of mycolactone A/B in 1999, the toxin responsible for this dramatic necrotic skin disease, resulted in a paradigm shift concerning the disease itself and in a broader sense, delineated an entirely new role for bioactive polyketides as virulence factors. The fascinating history, biology and chemistry of M. ulcerans infections are discussed in this review.
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Affiliation(s)
- Anne-Caroline Chany
- Université de Haute Alsace, Laboratoire de Chimie Organique et Bioorganique, EA4566, Ecole Nationale Supérieure de Chimie de Mulhouse, 3 rue Alfred Werner, 68093 Mulhouse Cedex, France
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Roupie V, Pidot SJ, Einarsdottir T, Van Den Poel C, Jurion F, Stinear TP, Huygen K. Analysis of the vaccine potential of plasmid DNA encoding nine mycolactone polyketide synthase domains in Mycobacterium ulcerans infected mice. PLoS Negl Trop Dis 2014; 8:e2604. [PMID: 24392169 PMCID: PMC3879250 DOI: 10.1371/journal.pntd.0002604] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 11/07/2013] [Indexed: 11/18/2022] Open
Abstract
There is no effective vaccine against Buruli ulcer. In experimental footpad infection of C57BL/6 mice with M. ulcerans, a prime-boost vaccination protocol using plasmid DNA encoding mycolyltransferase Ag85A of M. ulcerans and a homologous protein boost has shown significant, albeit transient protection, comparable to the one induced by M. bovis BCG. The mycolactone toxin is an obvious candidate for a vaccine, but by virtue of its chemical structure, this toxin is not immunogenic in itself. However, antibodies against some of the polyketide synthase domains involved in mycolactone synthesis, were found in Buruli ulcer patients and healthy controls from the same endemic region, suggesting that these domains are indeed immunogenic. Here we have analyzed the vaccine potential of nine polyketide synthase domains using a DNA prime/protein boost strategy. C57BL/6 mice were vaccinated against the following domains: acyl carrier protein 1, 2, and 3, acyltransferase (acetate) 1 and 2, acyltransferase (propionate), enoylreductase, ketoreductase A, and ketosynthase load module. As positive controls, mice were vaccinated with DNA encoding Ag85A or with M. bovis BCG. Strongest antigen specific antibodies could be detected in response to acyltransferase (propionate) and enoylreductase. Antigen-specific Th1 type cytokine responses (IL-2 or IFN-γ) were induced by vaccination against all antigens, and were strongest against acyltransferase (propionate). Finally, vaccination against acyltransferase (propionate) and enoylreductase conferred some protection against challenge with virulent M. ulcerans 1615. However, protection was weaker than the one conferred by vaccination with Ag85A or M. bovis BCG. Combinations of these polyketide synthase domains with the vaccine targeting Ag85A, of which the latter is involved in the integrity of the cell wall of the pathogen, and/or with live attenuated M. bovis BCG or mycolactone negative M. ulcerans may eventually lead to the development of an efficacious BU vaccine.
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Affiliation(s)
- Virginie Roupie
- Service Immunology, Scientific Institute of Public Health (WIV-ISP Site Ukkel), Brussels, Belgium
| | - Sacha J. Pidot
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Tobba Einarsdottir
- Service Immunology, Scientific Institute of Public Health (WIV-ISP Site Ukkel), Brussels, Belgium
| | - Christophe Van Den Poel
- Service Immunology, Scientific Institute of Public Health (WIV-ISP Site Ukkel), Brussels, Belgium
| | - Fabienne Jurion
- Service Immunology, Scientific Institute of Public Health (WIV-ISP Site Ukkel), Brussels, Belgium
| | - Timothy P. Stinear
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Kris Huygen
- Service Immunology, Scientific Institute of Public Health (WIV-ISP Site Ukkel), Brussels, Belgium
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