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Muhi S, Buultjens AH, Porter JL, Marshall JL, Doerflinger M, Pidot SJ, O’Brien DP, Johnson PDR, Lavender CJ, Globan M, McCarthy J, Osowicki J, Stinear TP. Mycobacterium ulcerans challenge strain selection for a Buruli ulcer controlled human infection model. PLoS Negl Trop Dis 2024; 18:e0011979. [PMID: 38701090 PMCID: PMC11095734 DOI: 10.1371/journal.pntd.0011979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 05/15/2024] [Accepted: 04/21/2024] [Indexed: 05/05/2024] Open
Abstract
Critical scientific questions remain regarding infection with Mycobacterium ulcerans, the organism responsible for the neglected tropical disease, Buruli ulcer (BU). A controlled human infection model has the potential to accelerate our knowledge of the immunological correlates of disease, to test prophylactic interventions and novel therapeutics. Here we present microbiological evidence supporting M. ulcerans JKD8049 as a suitable human challenge strain. This non-genetically modified Australian isolate is susceptible to clinically relevant antibiotics, can be cultured in animal-free and surfactant-free media, can be enumerated for precise dosing, and has stable viability following cryopreservation. Infectious challenge of humans with JKD8049 is anticipated to imitate natural infection, as M. ulcerans JKD8049 is genetically stable following in vitro passage and produces the key virulence factor, mycolactone. Also reported are considerations for the manufacture, storage, and administration of M. ulcerans JKD8049 for controlled human infection.
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Affiliation(s)
- Stephen Muhi
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
- Victorian Infectious Diseases Service, Royal Melbourne Hospital, Parkville, Victoria, Australia
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Andrew H. Buultjens
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jessica L. Porter
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Julia L. Marshall
- Department of Infectious Diseases, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Marcel Doerflinger
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Sacha J. Pidot
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Daniel P. O’Brien
- Victorian Infectious Diseases Service, Royal Melbourne Hospital, Parkville, Victoria, Australia
- Department of Infectious Diseases, Barwon Health, Geelong, Victoria, Australia
| | - Paul D. R. Johnson
- Northeast Public Health Unit, Austin Health, Heidelberg, Victoria, Australia
| | - Caroline J. Lavender
- Victorian Infectious Disease Reference Laboratory (VIDRL), Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Maria Globan
- Victorian Infectious Disease Reference Laboratory (VIDRL), Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - James McCarthy
- Victorian Infectious Diseases Service, Royal Melbourne Hospital, Parkville, Victoria, Australia
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Infectious Diseases, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Joshua Osowicki
- Tropical Diseases Research Group, Murdoch Children’s Research Institute, The Royal Children’s Hospital, Parkville, Victoria, Australia
- Infectious Diseases Unit, Department of General Medicine, Royal Children’s Hospital Melbourne, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Victoria, Australia
| | - Timothy P. Stinear
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
- Victorian Infectious Disease Reference Laboratory (VIDRL), Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
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2
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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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3
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Muhi S, Osowicki J, O'Brien D, Johnson PDR, Pidot S, Doerflinger M, Marshall JL, Pellegrini M, McCarthy J, Stinear TP. A human model of Buruli ulcer: The case for controlled human infection and considerations for selecting a Mycobacterium ulcerans challenge strain. PLoS Negl Trop Dis 2023; 17:e0011394. [PMID: 37384606 DOI: 10.1371/journal.pntd.0011394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023] Open
Abstract
Critical knowledge gaps regarding infection with Mycobacterium ulcerans, the cause of Buruli ulcer (BU), have impeded development of new therapeutic approaches and vaccines for prevention of this neglected tropical disease. Here, we review the current understanding of host-pathogen interactions and correlates of immune protection to explore the case for establishing a controlled human infection model of M. ulcerans infection. We also summarise the overarching safety considerations and present a rationale for selecting a suitable challenge strain.
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Affiliation(s)
- Stephen Muhi
- Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
- Victorian Infectious Diseases Service, Royal Melbourne Hospital, Parkville, Victoria, Australia
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Joshua Osowicki
- Tropical Diseases Research Group, Murdoch Children's Research Institute, The Royal Children's Hospital, Parkville, Victoria, Australia
- Infectious Diseases Unit, Department of General Medicine, Royal Children's Hospital Melbourne, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Victoria, Australia
| | - Daniel O'Brien
- Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
- Victorian Infectious Diseases Service, Royal Melbourne Hospital, Parkville, Victoria, Australia
- Barwon Health, Geelong, Victoria, Australia
| | - Paul D R Johnson
- Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
- Austin Health, Heidelberg, Victoria, Australia
| | - Sacha Pidot
- Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Marcel Doerflinger
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Julia L Marshall
- Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Marc Pellegrini
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - James McCarthy
- Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
- Victorian Infectious Diseases Service, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Timothy P Stinear
- Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
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4
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Ricci D, Demangel C. From Bacterial Toxin to Therapeutic Agent: The Unexpected Fate of Mycolactone. Toxins (Basel) 2023; 15:369. [PMID: 37368670 DOI: 10.3390/toxins15060369] [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: 05/13/2023] [Revised: 05/27/2023] [Accepted: 05/28/2023] [Indexed: 06/29/2023] Open
Abstract
"Recognizing a surprising fact is the first step towards discovery." This famous quote from Louis Pasteur is particularly appropriate to describe what led us to study mycolactone, a lipid toxin produced by the human pathogen Mycobacterium ulcerans. M. ulcerans is the causative agent of Buruli ulcer, a neglected tropical disease manifesting as chronic, necrotic skin lesions with a "surprising" lack of inflammation and pain. Decades after its first description, mycolactone has become much more than a mycobacterial toxin. This uniquely potent inhibitor of the mammalian translocon (Sec61) helped reveal the central importance of Sec61 activity for immune cell functions, the spread of viral particles and, unexpectedly, the viability of certain cancer cells. We report in this review the main discoveries that marked our research into mycolactone, and the medical perspectives they opened up. The story of mycolactone is not over and the applications of Sec61 inhibition may go well beyond immunomodulation, viral infections, and oncology.
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Affiliation(s)
- Daniela Ricci
- Institut Pasteur, Université Paris Cité, Inserm U1224, Immunobiology and Therapy Unit, 75015 Paris, France
| | - Caroline Demangel
- Institut Pasteur, Université Paris Cité, Inserm U1224, Immunobiology and Therapy Unit, 75015 Paris, France
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Dermody R, Ali F, Popovich J, Chen S, Seo DK, Haydel SE. Modified aluminosilicates display antibacterial activity against nontuberculous mycobacteria and adsorb mycolactone and Mycobacterium ulcerans in vitro. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.1016426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Mycobacterium ulcerans (MU) infection of skin and soft tissue leads to chronic skin ulceration known as Buruli ulcer. MU releases a lipid-like toxin, mycolactone, that diffuses into the tissue, effecting disease through localized tissue necrosis and immunosuppression. Cutaneous Buruli ulcer wounds slowly advance from a painless pre-ulcerative stage to an ulcerative lesion, leading to disparities in the timing of medical intervention and treatment outcomes. Novel Buruli ulcer wound management solutions could complement and supplement systemically administered antimicrobials and reduce time to healing. Capitalizing on nanopore structure, adsorption, and exchange capacities, aluminosilicate nanozeolites (nZeos) and geopolymers (GPs) were developed and investigated in the context of therapeutics for mycobacterial disease ulcerative wound care. nZeos were ion exchanged with copper or silver to assess the antimicrobial activity against MU and Mycobacterium marinum, a rapid growing, genetic ancestor of MU that also causes skin and soft tissue infections. Silver- and copper-exchanged nZeos were bactericidal against MU, while only silver-exchanged nZeos killed M. marinum. To mediate adsorption at a biological scale, GPs with different pore sizes and altered surface modifications were generated and assessed for the ability to adsorb MU and mycolactone. Macroporous GPs with and without stearic acid modification equivalently adsorbed MU cells, while mesoporous GPs with stearic acid adsorbed mycolactone toxin significantly better than mesoporous GPs or GPs modified with phenyltriethoxysilane (PTES). In cytotoxicity assays, Cu-nZeos lacked toxicity against Detroit 551, U-937, and WM-115 cells. GPs demonstrated limited cytotoxicity in Detroit 551 and WM-115, but produced time-dependent toxicity in U-937 cells. With their large surface area and adsorptive capacities, aluminosilicates nZeos and GPs may be modified and developed to support conventional BU wound care. Topical application of nZeos and GPs could kill MU within the cutaneous wound environment and physically remove MU and mycolactone with wound dressing changes, thereby improving wound healing and overall patient outcomes.
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Kawashima A, Kiriya M, En J, Tanigawa K, Nakamura Y, Fujiwara Y, Luo Y, Maruyama K, Watanabe S, Goto M, Suzuki K. Genome-wide screening identified SEC61A1 as an essential factor for mycolactone-dependent apoptosis in human premonocytic THP-1 cells. PLoS Negl Trop Dis 2022; 16:e0010672. [PMID: 35939511 PMCID: PMC9387930 DOI: 10.1371/journal.pntd.0010672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 08/18/2022] [Accepted: 07/18/2022] [Indexed: 11/21/2022] Open
Abstract
Buruli ulcer is a chronic skin disease caused by a toxic lipid mycolactone produced by Mycobacterium ulcerans, which induces local skin tissue destruction and analgesia. However, the cytotoxicity pathway induced by mycolactone remains largely unknown. Here we investigated the mycolactone-induced cell death pathway by screening host factors using a genome-scale lenti-CRISPR mutagenesis assay in human premonocytic THP-1 cells. As a result, 884 genes were identified as candidates causing mycolactone-induced cell death, among which SEC61A1, the α-subunit of the Sec61 translocon complex, was the highest scoring. CRISPR/Cas9 genome editing of SEC61A1 in THP-1 cells suppressed mycolactone-induced endoplasmic reticulum stress, especially eIF2α phosphorylation, and caspase-dependent apoptosis. Although previous studies have reported that mycolactone targets SEC61A1 based on mutation screening and structural analysis in several cell lines, we have reconfirmed that SEC61A1 is a mycolactone target by genome-wide screening in THP-1 cells. These results shed light on the cytotoxicity of mycolactone and suggest that the inhibition of mycolactone activity or SEC61A1 downstream cascades will be a novel therapeutic modality to eliminate the harmful effects of mycolactone in addition to the 8-week antibiotic regimen of rifampicin and clarithromycin. Buruli ulcer is a chronic skin disease caused by the bacterium Mycobacterium ulcerans. The disease mainly affects children in West Africa, and the skin ulcers are induced by mycolactone, a toxin produced by the bacteria. The mycolactone diffuses through the skin, killing cells, creating irreversible ulceration, and weakening host immune defenses. However, the cytotoxic pathway induced by mycolactone remains largely unknown. We evaluated the mycolactone-induced cell death pathway by screening host factors using a genome-scale knockout assay in human premonocytic THP-1 cells. We identified 884 genes that are potentially involved in mycolactone-induced cell death, of which SEC61A1, the α-subunit of the Sec61 translocon complex, was the highest ranking. Knockout of SEC61A1 in THP-1 cells resulted in suppression of endoplasmic reticulum stress and caspase-dependent apoptosis induced by mycolactone. These results suggest that SEC61A1 is an essential mediator of mycolactone-induced cell death.
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Affiliation(s)
- Akira Kawashima
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Tokyo, Japan
| | - Mitsuo Kiriya
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Tokyo, Japan
| | - Junichiro En
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Tokyo, Japan
- Department of Occupational Therapy, School of Health Science, International University of Health and Welfare, Narita, Japan
| | - Kazunari Tanigawa
- Department of Molecular Pharmaceutics, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Yasuhiro Nakamura
- Center for Promotion of Pharmaceutical Education & Research, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Yoko Fujiwara
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Tokyo, Japan
| | - Yuqian Luo
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Tokyo, Japan
- Department of Laboratory Medicine, Nanjing Drum Tower Hospital and Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Nanjing, China
| | - Keiji Maruyama
- Center for Promotion of Pharmaceutical Education & Research, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Shigekazu Watanabe
- Center for Promotion of Pharmaceutical Education & Research, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Masamichi Goto
- Department of Pathology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Koichi Suzuki
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Tokyo, Japan
- * E-mail:
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7
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Rifflet A, Demangel C, Guenin-Macé L. Mycolactone Purification from M. ulcerans Cultures and HPLC-Based Approaches for Mycolactone Quantification in Biological Samples. Methods Mol Biol 2022; 2387:117-130. [PMID: 34643908 DOI: 10.1007/978-1-0716-1779-3_13] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Mycolactones are a family of polyketide synthase products made by the human pathogen Mycobacterium ulcerans that were recently identified as novel inhibitors of the host membrane translocation complex (Sec61). Here, we provide protocols for the purification of mycolactones from bacterial cultures, and for their quantitative assessment in biological samples.
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Affiliation(s)
- Aline Rifflet
- Biology and Genetics of Bacterial Cell Wall, Institut Pasteur, Paris, France
- INSERM, Equipe Avenir, Paris, France
| | - Caroline Demangel
- Immunobiology of Infection Unit, Institut Pasteur, INSERM U1221, Paris, France
| | - Laure Guenin-Macé
- Immunobiology of Infection Unit, Institut Pasteur, INSERM U1221, Paris, France.
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8
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Mycolactone enhances the Ca2+ leak from endoplasmic reticulum by trapping Sec61 translocons in a Ca2+ permeable state. Biochem J 2021; 478:4005-4024. [PMID: 34726690 PMCID: PMC8650850 DOI: 10.1042/bcj20210345] [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: 05/14/2021] [Revised: 10/19/2021] [Accepted: 11/02/2021] [Indexed: 01/17/2023]
Abstract
The Mycobacterium ulcerans exotoxin, mycolactone, is an inhibitor of co-translational translocation via the Sec61 complex. Mycolactone has previously been shown to bind to, and alter the structure of the major translocon subunit Sec61α, and change its interaction with ribosome nascent chain complexes. In addition to its function in protein translocation into the ER, Sec61 also plays a key role in cellular Ca2+ homeostasis, acting as a leak channel between the endoplasmic reticulum (ER) and cytosol. Here, we have analysed the effect of mycolactone on cytosolic and ER Ca2+ levels using compartment-specific sensors. We also used molecular docking analysis to explore potential interaction sites for mycolactone on translocons in various states. These results show that mycolactone enhances the leak of Ca2+ ions via the Sec61 translocon, resulting in a slow but substantial depletion of ER Ca2+. This leak was dependent on mycolactone binding to Sec61α because resistance mutations in this protein completely ablated the increase. Molecular docking supports the existence of a mycolactone-binding transient inhibited state preceding translocation and suggests mycolactone may also bind Sec61α in its idle state. We propose that delayed ribosomal release after translation termination and/or translocon ‘breathing' during rapid transitions between the idle and intermediate-inhibited states allow for transient Ca2+ leak, and mycolactone's stabilisation of the latter underpins the phenotype observed.
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9
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Overview: Mycolactone , the Macrolide Toxin of Mycobacterium ulcerans. Methods Mol Biol 2021. [PMID: 34643906 DOI: 10.1007/978-1-0716-1779-3_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The acquisition by a Mycobacterium marinum-like progenitor of a plasmid encoding enzymes for the biosynthesis of the highly potent macrolide toxin mycolactone has set off the evolution of M. ulcerans toward a new mycobacterial species. While the selective advantage of producing mycolactone for survival in environmental niche(s) of the pathogen is unclear, there is no doubt that the cytotoxic, immunomodulatory, and analgesic properties of mycolactone are key for the establishment and progression of M. ulcerans infections in the host. Improved procedures for the isolation, handling, and detection of the amphiphilic and light-sensitive toxin have facilitated studies to unravel molecular mechanisms of mycolactone action on host cells in vitro and on cellular and immune responses in animal models. The pivotal role of mycolactone in the pathology of Buruli ulcer and the fact that the toxin has not been associated with other pathogens make it an ideal target for therapeutics/vaccines aiming at mycolactone neutralization and for the development of assays for the diagnosis of the disease.
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10
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Conditions for Handling and Optimal Storage of Mycolactone. Methods Mol Biol 2021. [PMID: 34643907 DOI: 10.1007/978-1-0716-1779-3_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The successful isolation of mycolactone in a laboratory or from a clinical sample relies on proper handling and storage of the toxin. Mycolactone is a light-sensitive and an amphiphilic toxin produced by Mycobacterium ulcerans. The biochemistry of the toxin makes it unstable in aqueous matrices such as blood, which causes it to self-aggregate or present in complex with carrier molecules. This biochemistry also impacts the use of the toxin in vitro, in that it tends to aggregate and stick to substrates in an aqueous environment, which alters its physiological presentation and limits its availability in a sample. Glass materials (i.e., tubes, vials, syringes, plates) should be used when possible to avoid loss of mycolactone sticking to plastic surfaces. Dark containers such as amber vials or aluminum-foil wrapped tubes should be used to avoid photodegradation of the toxin upon exposure to light. Sample storage in organic solvents is ideal for mycolactone stability and recovery; however, this is not always amenable as multiple diagnostic assays might be performed on a single sample (such as PCR or ELISA). In these cases, samples can be stored in an aqueous solution containing a small amount of detergent to enhance recovery of the toxin, and in order to avoid aggregation. Therefore, the downstream manipulations should be carefully considered prior to sample collection and storage. Here we present considerations for the optimal handling and storage of mycolactone in order to obtain quality yield of the toxin for various research and diagnostic applications.
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11
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Warryn L, Dangy JP, Gersbach P, Gehringer M, Altmann KH, Pluschke G. An Antigen Capture Assay for the Detection of Mycolactone, the Polyketide Toxin of Mycobacterium ulcerans. THE JOURNAL OF IMMUNOLOGY 2021; 206:2753-2762. [PMID: 34031146 DOI: 10.4049/jimmunol.2001232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/29/2021] [Indexed: 11/19/2022]
Abstract
Mycolactone is a cytotoxin responsible for most of the chronic necrotizing pathology of Mycobacterium ulcerans disease (Buruli ulcer). The polyketide toxin consists of a 12-membered lactone ring with a lower O-linked polyunsaturated acyl side chain and an upper C-linked side chain. Mycolactone is unique to M. ulcerans and an immunological Ag capture assay would represent an important tool for the study of Buruli ulcer pathogenesis and for laboratory diagnosis. When testing sets of mycolactone-specific mouse mAbs, we found that Abs against the hydrophobic lower side chain only bind mycolactone immobilized on a solid support but not when present in solution. This observation supports previous findings that mycolactone forms micellar structures in aqueous solution with the hydrophobic region sequestered into the inner core of the aggregates. Although an Ag capture assay typically requires two Abs that recognize nonoverlapping epitopes, our search for matching pairs of mAbs showed that the same mAb could be used both as capture and as detecting reagent for the detection of the mycolactone aggregates. However, the combination of a core-specific and a core/upper side chain-specific mAb constituted the most sensitive ELISA with a sensitivity in the low nanogram range. The results of a pilot experiment showed that the sensitivity of the assay is sufficient to detect mycolactone in swab samples from Buruli ulcer lesions. Although the described capture ELISA can serve as a tool for research on the biology of mycolactone, the assay system will have to be adapted for use as a diagnostic tool.
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Affiliation(s)
- Louisa Warryn
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland; and
| | - Jean-Pierre Dangy
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland; and
| | - Philipp Gersbach
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology Zürich, Zürich, Switzerland
| | - Matthias Gehringer
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology Zürich, Zürich, Switzerland
| | - Karl-Heinz Altmann
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology Zürich, Zürich, Switzerland
| | - Gerd Pluschke
- Swiss Tropical and Public Health Institute, Basel, Switzerland; .,University of Basel, Basel, Switzerland; and
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12
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Fevereiro J, Fraga AG, Pedrosa J. Genetics in the Host-Mycobacterium ulcerans interaction. Immunol Rev 2021; 301:222-241. [PMID: 33682158 DOI: 10.1111/imr.12958] [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: 01/05/2021] [Revised: 01/30/2021] [Accepted: 02/01/2021] [Indexed: 11/30/2022]
Abstract
Buruli ulcer is an emerging infectious disease associated with high morbidity and unpredictable outbreaks. It is caused by Mycobacterium ulcerans, a slow-growing pathogen evolutionarily shaped by the acquisition of a plasmid involved in the production of a potent macrolide-like cytotoxin and by genome rearrangements and downsizing. These events culminated in an uncommon infection pattern, whereby M. ulcerans is both able to induce the initiation of the inflammatory cascade and the cell death of its proponents, as well as to survive within the phagosome and in the extracellular milieu. In such extreme conditions, the host is sentenced to rely on a highly orchestrated genetic landscape to be able to control the infection. We here revisit the dynamics of M. ulcerans infection, drawing parallels from other mycobacterioses and integrating the most recent knowledge on its evolution and pathogenicity in its interaction with the host immune response.
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Affiliation(s)
- João Fevereiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Alexandra G Fraga
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Jorge Pedrosa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
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13
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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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14
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Warryn L, Dangy JP, Gersbach P, Gehringer M, Schäfer A, Ruf MT, Ruggli N, Altmann KH, Pluschke G. Development of an ELISA for the quantification of mycolactone, the cytotoxic macrolide toxin of Mycobacterium ulcerans. PLoS Negl Trop Dis 2020; 14:e0008357. [PMID: 32589646 PMCID: PMC7347236 DOI: 10.1371/journal.pntd.0008357] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 07/09/2020] [Accepted: 05/04/2020] [Indexed: 01/04/2023] Open
Abstract
Mycolactones, macrolide cytotoxins, are key virulence factors of Mycobacterium ulcerans, the etiological agent of the chronic necrotizing skin disease Buruli ulcer. There is urgent need for a simple point-of-care laboratory test for Buruli ulcer and mycolactone represents a promising target for the development of an immunological assay. However, for a long time, all efforts to generate mycolactone-specific antibodies have failed. By using a protein conjugate of a truncated non-toxic synthetic mycolactone derivative, we recently described generation of a set of mycolactone-specific monoclonal antibodies. Using the first mycolactone-specific monoclonal antibodies that we have described before, we were able to develop an antigen competition assay that detects mycolactones. By the systematic selection of a capturing antibody and a reporter molecule, and the optimization of assay conditions, we developed an ELISA that detects common natural variants of mycolactone with a limit of detection in the low nanomolar range. The mycolactone-specific ELISA described here will be a very useful tool for research on the biology of this macrolide toxin. After conversion into a simple point-of-care test format, the competition assay may have great potential as laboratory assay for both the diagnosis of Buruli ulcer and for the monitoring of treatment efficacy.
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Affiliation(s)
- Louisa Warryn
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Jean-Pierre Dangy
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Philipp Gersbach
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Zürich, Switzerland
| | - Matthias Gehringer
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Zürich, Switzerland
| | - Anja Schäfer
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Marie-Thérèse Ruf
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Nicolas Ruggli
- The Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland
| | - Karl-Heinz Altmann
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Zürich, Switzerland
| | - Gerd Pluschke
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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15
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Röltgen K, Pluschke G. Buruli ulcer: The Efficacy of Innate Immune Defense May Be a Key Determinant for the Outcome of Infection With Mycobacterium ulcerans. Front Microbiol 2020; 11:1018. [PMID: 32523571 PMCID: PMC7261859 DOI: 10.3389/fmicb.2020.01018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/24/2020] [Indexed: 12/18/2022] Open
Abstract
Buruli ulcer (BU) is a neglected, tropical infectious disease of the skin and the subcutaneous tissue caused by Mycobacterium ulcerans. This pathogen has emerged as a new species from a common ancestor with Mycobacterium marinum by acquisition of the virulence plasmid pMUM. The plasmid encodes enzymes required for the synthesis of the macrolide toxin mycolactone, which has cytotoxic and immunosuppressive activities. In advanced BU lesions, extracellular clusters of M. ulcerans reside in necrotic subcutaneous tissue and are protected from infiltrating leukocytes by the cytotoxic activity of secreted mycolactone. Several lines of evidence indicate that elements of the innate immune system eliminate in many cases the initial inoculum before bacterial clusters can form and that therefore exposure to M. ulcerans leads only in a minority of individuals to the characteristic chronic necrotizing BU lesions. It is assumed that phagocytes play a key role in early host defense against M. ulcerans. Antibodies against bacterial surface structures seem to have less potential to enhance innate immunity than TH1 cell responses. Precise innate and adaptive immune effector mechanisms leading to protective immunity are however unclear, complicating the development of effective vaccines, the most desired solution to control BU. The tuberculosis vaccine Mycobacterium bovis Bacillus Calmette–Guérin (BCG) has limited short-term protective activity against BU. Whether this effect is due to the broad antigenic cross-reactivity between M. bovis and M. ulcerans or is at least partly mediated by a non-specific enhanced responsiveness of innate immune cells to secondary stimulation, recently described as “trained immunity” or “innate immune memory” is unknown but has major implications for vaccine design. Current vaccine research and development activities are focusing on recombinant BCG, subunit vaccines with selected M. ulcerans proteins, and the neutralization of mycolactone.
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Affiliation(s)
- Katharina Röltgen
- Department of Pathology, Stanford School of Medicine, Stanford University, Stanford, CA, United States
| | - Gerd Pluschke
- Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
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16
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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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17
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Gehringer M, Mäder P, Gersbach P, Pfeiffer B, Scherr N, Dangy JP, Pluschke G, Altmann KH. Configurationally Stabilized Analogs of M. ulcerans Exotoxins Mycolactones A and B Reveal the Importance of Side Chain Geometry for Mycolactone Virulence. Org Lett 2019; 21:5853-5857. [PMID: 31295000 DOI: 10.1021/acs.orglett.9b01947] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Mycolactones A/B (1a/b) are exotoxins of Mycobacterium ulcerans that are the molecular cause of Buruli ulcer. 1a/b represent a rapidly equilibrating mixture of Z/E isomers about the C4'═C5' double bond of the C5-side chain. Here, we describe the syntheses of mycolactone analogs with configurationally stable C5-side chains (2a, E mimetic; 2b/c, Z mimetics). Based on the cytotoxicity of 2a-c, the Δ4',5'-trans isomer of mycolactones A/B (1b) appears to be the major virulence factor.
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Affiliation(s)
- Matthias Gehringer
- Swiss Federal Institute of Technology (ETH) Zürich , Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences , Vladimir-Prelog-Weg 4 , 8093 Zürich , Switzerland
| | - Patrick Mäder
- Swiss Federal Institute of Technology (ETH) Zürich , Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences , Vladimir-Prelog-Weg 4 , 8093 Zürich , Switzerland
| | - Philipp Gersbach
- Swiss Federal Institute of Technology (ETH) Zürich , Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences , Vladimir-Prelog-Weg 4 , 8093 Zürich , Switzerland
| | - Bernhard Pfeiffer
- Swiss Federal Institute of Technology (ETH) Zürich , Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences , Vladimir-Prelog-Weg 4 , 8093 Zürich , Switzerland
| | - Nicole Scherr
- Swiss Tropical and Public Health Institute , Socinstrasse 57 , 4002 Basel , Switzerland
| | - Jean-Pierre Dangy
- Swiss Tropical and Public Health Institute , Socinstrasse 57 , 4002 Basel , Switzerland
| | - Gerd Pluschke
- Swiss Tropical and Public Health Institute , Socinstrasse 57 , 4002 Basel , Switzerland
| | - Karl-Heinz Altmann
- Swiss Federal Institute of Technology (ETH) Zürich , Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences , Vladimir-Prelog-Weg 4 , 8093 Zürich , Switzerland
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18
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Zong G, Hu Z, O’Keefe S, Tranter D, Iannotti MJ, Baron L, Hall B, Corfield K, Paatero AO, Henderson MJ, Roboti P, Zhou J, Sun X, Govindarajan M, Rohde JM, Blanchard N, Simmonds R, Inglese J, Du Y, Demangel C, High S, Paavilainen VO, Shi WQ. Ipomoeassin F Binds Sec61α to Inhibit Protein Translocation. J Am Chem Soc 2019; 141:8450-8461. [PMID: 31059257 PMCID: PMC6627486 DOI: 10.1021/jacs.8b13506] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ipomoeassin F is a potent natural cytotoxin that inhibits growth of many tumor cell lines with single-digit nanomolar potency. However, its biological and pharmacological properties have remained largely unexplored. Building upon our earlier achievements in total synthesis and medicinal chemistry, we used chemical proteomics to identify Sec61α (protein transport protein Sec61 subunit alpha isoform 1), the pore-forming subunit of the Sec61 protein translocon, as a direct binding partner of ipomoeassin F in living cells. The interaction is specific and strong enough to survive lysis conditions, enabling a biotin analogue of ipomoeassin F to pull down Sec61α from live cells, yet it is also reversible, as judged by several experiments including fluorescent streptavidin staining, delayed competition in affinity pulldown, and inhibition of TNF biogenesis after washout. Sec61α forms the central subunit of the ER protein translocation complex, and the binding of ipomoeassin F results in a substantial, yet selective, inhibition of protein translocation in vitro and a broad ranging inhibition of protein secretion in live cells. Lastly, the unique resistance profile demonstrated by specific amino acid single-point mutations in Sec61α provides compelling evidence that Sec61α is the primary molecular target of ipomoeassin F and strongly suggests that the binding of this natural product to Sec61α is distinctive. Therefore, ipomoeassin F represents the first plant-derived, carbohydrate-based member of a novel structural class that offers new opportunities to explore Sec61α function and to further investigate its potential as a therapeutic target for drug discovery.
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Affiliation(s)
- Guanghui Zong
- †Department
of Chemistry and Biochemistry and ⬡Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, United States,Department
of Chemistry and Biochemistry, University
of Maryland, College Park, Maryland 20742, United States
| | - Zhijian Hu
- †Department
of Chemistry and Biochemistry and ⬡Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Sarah O’Keefe
- School
of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, United Kingdom
| | - Dale Tranter
- University
of Helsinki, HiLIFE, Helsinki, Finland,Institute
of Biotechnology, Helsinki, Finland
| | - Michael J. Iannotti
- National
Center for Advancing Translational Sciences, National
Institutes of Health, Rockville, Maryland 20850, United States
| | - Ludivine Baron
- Immunobiology
of Infection Unit, Institut Pasteur, 75015 Paris, France,INSERM, U1221, 75005 Paris, France
| | - Belinda Hall
- Department
of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
| | - Katherine Corfield
- Department
of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
| | - Anja O. Paatero
- University
of Helsinki, HiLIFE, Helsinki, Finland,Institute
of Biotechnology, Helsinki, Finland
| | - Mark J. Henderson
- National
Center for Advancing Translational Sciences, National
Institutes of Health, Rockville, Maryland 20850, United States
| | - Peristera Roboti
- School
of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, United Kingdom
| | - Jianhong Zhou
- †Department
of Chemistry and Biochemistry and ⬡Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Xianwei Sun
- †Department
of Chemistry and Biochemistry and ⬡Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, United States,Department
of Radiology, Baylor College of Medicine, Houston, Texas 77030, United States
| | - Mugunthan Govindarajan
- †Department
of Chemistry and Biochemistry and ⬡Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, United States,Emory
Institute for Drug Development, Emory University, 954 Gatewood Road, Atlanta, Georgia 30329, United States
| | - Jason M. Rohde
- National
Center for Advancing Translational Sciences, National
Institutes of Health, Rockville, Maryland 20850, United States
| | - Nicolas Blanchard
- Université
de Haute-Alsace, Université de Strasbourg, CNRS, LIMA, UMR 7042, 68000 Mulhouse, France
| | - Rachel Simmonds
- Department
of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom,
| | - James Inglese
- National
Center for Advancing Translational Sciences, National
Institutes of Health, Rockville, Maryland 20850, United States,
| | - Yuchun Du
- †Department
of Chemistry and Biochemistry and ⬡Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, United States,
| | - Caroline Demangel
- Immunobiology
of Infection Unit, Institut Pasteur, 75015 Paris, France,INSERM, U1221, 75005 Paris, France,
| | - Stephen High
- School
of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, United Kingdom,
| | - Ville O. Paavilainen
- University
of Helsinki, HiLIFE, Helsinki, Finland,Institute
of Biotechnology, Helsinki, Finland,
| | - Wei Q. Shi
- †Department
of Chemistry and Biochemistry and ⬡Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, United States,Department
of Chemistry, Ball State University, Muncie, Indiana 47306, United States,;
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19
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Kubicek-Sutherland JZ, Vu DM, Anderson AS, Sanchez TC, Converse PJ, Martí-Arbona R, Nuermberger EL, Swanson BI, Mukundan H. Understanding the Significance of Biochemistry in the Storage, Handling, Purification, and Sampling of Amphiphilic Mycolactone. Toxins (Basel) 2019; 11:toxins11040202. [PMID: 30987300 PMCID: PMC6520765 DOI: 10.3390/toxins11040202] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/26/2019] [Accepted: 04/01/2019] [Indexed: 12/29/2022] Open
Abstract
Mycolactone, the amphiphilic macrolide toxin secreted by Mycobacterium ulcerans, plays a significant role in the pathology and manifestations of Buruli ulcer (BU). Consequently, it follows that the toxin is a suitable target for the development of diagnostics and therapeutics for this disease. Yet, several challenges have deterred such development. For one, the lipophilic nature of the toxin makes it difficult to handle and store and contributes to variability associated with laboratory experimentation and purification yields. In this manuscript, we have attempted to incorporate our understanding of the lipophilicity of mycolactone in order to define the optimal methods for the storage, handling, and purification of this toxin. We present a systematic correlation of variability associated with measurement techniques (thin-layer chromatography (TLC), mass spectrometry (MS), and UV-Vis spectrometry), storage conditions, choice of solvents, as well as the impact of each of these on toxin function as assessed by cellular cytotoxicity. We also compared natural mycolactone extracted from bacterial culture with synthesized toxins in laboratory (solvents, buffers) and physiologically relevant (serum) matrices. Our results point to the greater stability of mycolactone in organic, as well as detergent-containing, solvents, regardless of the container material (plastic, glass, or silanized tubes). They also highlight the presence of toxin in samples that may be undetectable by any one technique, suggesting that each detection approach captures different configurations of the molecule with varying specificity and sensitivity. Most importantly, our results demonstrate for the very first time that amphiphilic mycolactone associates with host lipoproteins in serum, and that this association will likely impact our ability to study, diagnose, and treat Buruli ulcers in patients.
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Affiliation(s)
| | - Dung M Vu
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
| | - Aaron S Anderson
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
| | - Timothy C Sanchez
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
| | - Paul J Converse
- Department of Medicine, Johns Hopkins University Center for Tuberculosis Research, Baltimore, MD 21218, USA.
| | | | - Eric L Nuermberger
- Department of Medicine, Johns Hopkins University Center for Tuberculosis Research, Baltimore, MD 21218, USA.
| | - Basil I Swanson
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
| | - Harshini Mukundan
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
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20
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Aboagye SY, Kpeli G, Tuffour J, Yeboah‐Manu D. Challenges associated with the treatment of Buruli ulcer. J Leukoc Biol 2018; 105:233-242. [PMID: 30168876 DOI: 10.1002/jlb.mr0318-128] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 07/19/2018] [Indexed: 12/30/2022] Open
Affiliation(s)
- Sammy Yaw Aboagye
- Noguchi Memorial Institute for Medical ResearchUniversity of Ghana Accra Ghana
| | - Grace Kpeli
- University of Allied Health Sciences Ho Ghana
| | | | - Dorothy Yeboah‐Manu
- Noguchi Memorial Institute for Medical ResearchUniversity of Ghana Accra Ghana
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21
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Membrane perturbing properties of toxin mycolactone from Mycobacterium ulcerans. PLoS Comput Biol 2018; 14:e1005972. [PMID: 29401455 PMCID: PMC5814095 DOI: 10.1371/journal.pcbi.1005972] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 02/15/2018] [Accepted: 01/15/2018] [Indexed: 12/16/2022] Open
Abstract
Mycolactone is the exotoxin produced by Mycobacterium ulcerans and is the virulence factor behind the neglected tropical disease Buruli ulcer. The toxin has a broad spectrum of biological effects within the host organism, stemming from its interaction with at least two molecular targets and the inhibition of protein uptake into the endoplasmic reticulum. Although it has been shown that the toxin can passively permeate into host cells, it is clearly lipophilic. Association with lipid carriers would have substantial implications for the toxin’s distribution within a host organism, delivery to cellular targets, diagnostic susceptibility, and mechanisms of pathogenicity. Yet the toxin’s interactions with, and distribution in, lipids are unknown. Herein we have used coarse-grained molecular dynamics simulations, guided by all-atom simulations, to study the interaction of mycolactone with pure and mixed lipid membranes. Using established techniques, we calculated the toxin’s preferential localization, membrane translocation, and impact on membrane physical and dynamical properties. The computed water-octanol partition coefficient indicates that mycolactone prefers to be in an organic phase rather than in an aqueous environment. Our results show that in a solvated membrane environment the exotoxin mainly localizes in the water-membrane interface, with a preference for the glycerol moiety of lipids, consistent with the reported studies that found it in lipid extracts of the cell. The calculated association constant to the model membrane is similar to the reported association constant for Wiskott-Aldrich syndrome protein. Mycolactone is shown to modify the physical properties of membranes, lowering the transition temperature, compressibility modulus, and critical line tension at which pores can be stabilized. It also shows a tendency to behave as a linactant, a molecule that localizes at the boundary between different fluid lipid domains in membranes and promotes inter-mixing of domains. This property has implications for the toxin’s cellular access, T-cell immunosuppression, and therapeutic potential. Mycolactone is a macrolide exotoxin secreted by Mycobacterium ulcerans, which causes a skin disease called Buruli ulcer, a neglected emerging disease. It is the third most common mycobacterial disease after tuberculosis and leprosy. Studies have shown how mycolactone plays a pivotal role in Buruli ulcer pathogenesis, and identified it as an attractive therapeutic target. This multifunctional cytotoxin exerts multiple local and global responses, including ulcerative, analgesic, and anti-inflammatory effects. Prompted by its lipid-like structure, we used extensive multi-resolution simulations to probe mycolactone’s interactions with model membranes. Our results suggest that mycolactone is sequestered in membranes where it alters several dynamical, physical, and mechanical properties. It also behaves as a linactant, localizing at the interface between lipid domains and decreasing the inter-domain line tension. Our results shed light on how mycolactone permeates host cell membranes and is distributed between lipid and aqueous environments. These findings have significant implications for the toxin’s distribution in the host environment and mechanisms of pathogenicity. Understanding the toxin’s distribution and mechanism of trafficking will have ramifications for targeted diagnostics, therapeutic approaches, and our understanding of Buruli ulcer pathogenesis.
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22
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Ruf MT, Steffen C, Bolz M, Schmid P, Pluschke G. Infiltrating leukocytes surround early Buruli ulcer lesions, but are unable to reach the mycolactone producing mycobacteria. Virulence 2017; 8:1918-1926. [PMID: 28873327 PMCID: PMC5810495 DOI: 10.1080/21505594.2017.1370530] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Affiliation(s)
- Marie-Thérèse Ruf
- a Swiss Tropical and Public Health Institute , Basel , Switzerland.,b University of Basel , Basel , Switzerland
| | - Christina Steffen
- c Department of Surgery , Cairns Hospital , Cairns , QLD , Australia
| | - Miriam Bolz
- a Swiss Tropical and Public Health Institute , Basel , Switzerland.,b University of Basel , Basel , Switzerland
| | - Peter Schmid
- a Swiss Tropical and Public Health Institute , Basel , Switzerland.,b University of Basel , Basel , Switzerland
| | - Gerd Pluschke
- a Swiss Tropical and Public Health Institute , Basel , Switzerland.,b University of Basel , Basel , Switzerland
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23
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Gehringer M, Altmann KH. The chemistry and biology of mycolactones. Beilstein J Org Chem 2017; 13:1596-1660. [PMID: 28904608 PMCID: PMC5564285 DOI: 10.3762/bjoc.13.159] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 07/21/2017] [Indexed: 12/21/2022] Open
Abstract
Mycolactones are a group of macrolides excreted by the human pathogen Mycobacterium ulcerans, which exhibit cytotoxic, immunosuppressive and analgesic properties. As the virulence factor of M. ulcerans, mycolactones are central to the pathogenesis of the neglected disease Buruli ulcer, a chronic and debilitating medical condition characterized by necrotic skin ulcers. Due to their complex structure and fascinating biology, mycolactones have inspired various total synthesis endeavors and structure-activity relationship studies. Although this review intends to cover all synthesis efforts in the field, special emphasis is given to the comparison of conceptually different approaches and to the discussion of more recent contributions. Furthermore, a detailed discussion of molecular targets and structure-activity relationships is provided.
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Affiliation(s)
- Matthias Gehringer
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zürich, Vladimir-Prelog-Weg 4, 8093 Zürich, Switzerland
| | - Karl-Heinz Altmann
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zürich, Vladimir-Prelog-Weg 4, 8093 Zürich, Switzerland
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24
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Bieri R, Scherr N, Ruf MT, Dangy JP, Gersbach P, Gehringer M, Altmann KH, Pluschke G. The Macrolide Toxin Mycolactone Promotes Bim-Dependent Apoptosis in Buruli Ulcer through Inhibition of mTOR. ACS Chem Biol 2017; 12:1297-1307. [PMID: 28294596 DOI: 10.1021/acschembio.7b00053] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Mycolactone, the macrolide exotoxin produced by Mycobacterium ulcerans, is central to the pathogenesis of the chronic necrotizing skin disease Buruli ulcer (BU). Here we show that mycolactone acts as an inhibitor of the mechanistic Target of Rapamycin (mTOR) signaling pathway by interfering with the assembly of the two distinct mTOR protein complexes mTORC1 and mTORC2, which regulate different cellular processes. Inhibition of the assembly of the rictor containing mTORC2 complex by mycolactone prevents phosphorylation of the serine/threonine protein kinase Akt. The associated inactivation of Akt leads to the dephosphorylation and activation of the Akt-targeted transcription factor FoxO3. Subsequent up-regulation of the FoxO3 target gene BCL2L11 (Bim) increases expression of the pro-apoptotic regulator Bim, driving mycolactone treated mammalian cells into apoptosis. The central role of Bim-dependent apoptosis in BU pathogenesis deduced from our experiments with cultured mammalian cells was further verified in an experimental M. ulcerans infection model. As predicted by the model, M. ulcerans infected Bim knockout mice did not develop necrotic BU lesions with large clusters of extracellular bacteria, but were able to contain the mycobacterial multiplication. Our findings provide a new coherent and comprehensive concept of BU pathogenesis.
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Affiliation(s)
- Raphael Bieri
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
- University of Basel, Petersplatz
1, 4003 Basel, Switzerland
| | - Nicole Scherr
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
- University of Basel, Petersplatz
1, 4003 Basel, Switzerland
| | - Marie-Thérèse Ruf
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
- University of Basel, Petersplatz
1, 4003 Basel, Switzerland
| | - Jean-Pierre Dangy
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
- University of Basel, Petersplatz
1, 4003 Basel, Switzerland
| | - Philipp Gersbach
- Department
of Chemistry and Applied Biosciences, Institute of Pharmaceutical
Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Matthias Gehringer
- Department
of Chemistry and Applied Biosciences, Institute of Pharmaceutical
Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Karl-Heinz Altmann
- Department
of Chemistry and Applied Biosciences, Institute of Pharmaceutical
Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Gerd Pluschke
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
- University of Basel, Petersplatz
1, 4003 Basel, Switzerland
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25
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Babu VS, Zhou Y, Kishi Y. Design, synthesis, and cytotoxicity of stabilized mycolactone analogs. Bioorg Med Chem Lett 2017; 27:1274-1277. [PMID: 28159417 DOI: 10.1016/j.bmcl.2017.01.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/11/2017] [Accepted: 01/12/2017] [Indexed: 11/16/2022]
Abstract
On exposure to visible light, mycolactone A/B, the causative toxin of Buruli ulcer, rearranges to a mixture of four photo-mycolactones apparently via a rare photochemically-induced [4πs+2πa] cycloaddition. In order to prevent the rearrangement, two C6'-C7' dihydromycolactone analogs 6'α-15 and 6'β-15 were designed and synthesized. 6'α-15 and 6'β-15 were shown to be stable under not only photochemical, but also acidic and basic conditions. Cytotoxicity was tested against arbitrarily chosen four cell lines (human Hek-293, human lung carcinoma A-549, human melanoma LOX-IMVI, and mouse L-929), thereby revealing that: (1) both analogs maintain potent cytotoxicity; (2) 6'β-15 exhibits significantly higher potency against human cell lines than 6'α-15; (3) in comparison with parent mycolactone A/B, 6'β-15 exhibits equal potency against human Hek-293, whereas significantly lower potency against human lung carcinoma A-549 and human melanoma LOX-IMVI.
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Affiliation(s)
- Vaddela Sudheer Babu
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA
| | - Ya Zhou
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA
| | - Yoshito Kishi
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
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Saint-Auret S, Abdelkafi H, Le Nouen D, Bisseret P, Blanchard N. Synthetic strategies towards mycolactone A/B, an exotoxin secreted by Mycobacterium ulcerans. Org Chem Front 2017. [DOI: 10.1039/c7qo00608j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Pitfalls and dead-ends pave the way to mycolactone A/B. This full account reports synthetic efforts towards this natural product that eventually culminated in a de novo total synthesis.
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Affiliation(s)
- Sarah Saint-Auret
- Université de Strasbourg
- CNRS
- Laboratoire de Chimie Moléculaire UMR 7509
- 67000 Strasbourg
- France
| | - Hajer Abdelkafi
- Université de Strasbourg
- CNRS
- Laboratoire de Chimie Moléculaire UMR 7509
- 67000 Strasbourg
- France
| | - Didier Le Nouen
- Université de Haute-Alsace
- Laboratoire de Chimie Organique et Bioorganique EA 4566
- 68093 Mulhouse Cedex
- France
| | - Philippe Bisseret
- Université de Strasbourg
- CNRS
- Laboratoire de Chimie Moléculaire UMR 7509
- 67000 Strasbourg
- France
| | - Nicolas Blanchard
- Université de Strasbourg
- CNRS
- Laboratoire de Chimie Moléculaire UMR 7509
- 67000 Strasbourg
- France
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27
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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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Dangy JP, Scherr N, Gersbach P, Hug MN, Bieri R, Bomio C, Li J, Huber S, Altmann KH, Pluschke G. Antibody-Mediated Neutralization of the Exotoxin Mycolactone, the Main Virulence Factor Produced by Mycobacterium ulcerans. PLoS Negl Trop Dis 2016; 10:e0004808. [PMID: 27351976 PMCID: PMC4924874 DOI: 10.1371/journal.pntd.0004808] [Citation(s) in RCA: 26] [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: 04/16/2016] [Accepted: 06/06/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Mycolactone, the macrolide exotoxin produced by Mycobacterium ulcerans, causes extensive tissue destruction by inducing apoptosis of host cells. In this study, we aimed at the production of antibodies that could neutralize the cytotoxic activities of mycolactone. METHODOLOGY/PRINCIPAL FINDINGS Using the B cell hybridoma technology, we generated a series of monoclonal antibodies with specificity for mycolactone from spleen cells of mice immunized with the protein conjugate of a truncated synthetic mycolactone derivative. L929 fibroblasts were used as a model system to investigate whether these antibodies can inhibit the biological effects of mycolactone. By measuring the metabolic activity of the fibroblasts, we found that anti-mycolactone mAbs can completely neutralize the cytotoxic activity of mycolactone. CONCLUSIONS/SIGNIFICANCE The toxin neutralizing capacity of anti-mycolactone mAbs supports the concept of evaluating the macrolide toxin as vaccine target.
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Affiliation(s)
- Jean-Pierre Dangy
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Nicole Scherr
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Philipp Gersbach
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Zürich, Switzerland
| | - Melanie N. Hug
- Roche Innovation Center, Chemical Biology, Basel, Switzerland
| | - Raphael Bieri
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Claudio Bomio
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Zürich, Switzerland
| | - Jun Li
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Zürich, Switzerland
| | - Sylwia Huber
- Roche Innovation Center, Chemical Biology, Basel, Switzerland
| | - Karl-Heinz Altmann
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Zürich, Switzerland
| | - Gerd Pluschke
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
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29
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Guenin-Macé L, Baron L, Chany AC, Tresse C, Saint-Auret S, Jönsson F, Le Chevalier F, Bruhns P, Bismuth G, Hidalgo-Lucas S, Bisson JF, Blanchard N, Demangel C. Shaping mycolactone for therapeutic use against inflammatory disorders. Sci Transl Med 2016; 7:289ra85. [PMID: 26019221 DOI: 10.1126/scitranslmed.aab0458] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Inflammation adversely affects the health of millions of people worldwide, and there is an unmet medical need for better anti-inflammatory drugs. We evaluated the therapeutic interest of mycolactone, a polyketide-derived macrolide produced by Mycobacterium ulcerans. Bacterial production of mycolactone in human skin causes a combination of ulcerative, analgesic, and anti-inflammatory effects. Whereas ulcer formation is mediated by the proapoptotic activity of mycolactone on skin cells via hyperactivation of Wiskott-Aldrich syndrome proteins, analgesia results from neuronal hyperpolarization via signaling through angiotensin II type 2 receptors. Mycolactone also blunts the capacity of immune cells to produce inflammatory mediators by an independent mechanism of protein synthesis blockade. In an attempt to isolate the structural determinants of mycolactone's immunosuppressive activity, we screened a library of synthetic subunits of mycolactone for inhibition of cytokine production by activated T cells. The minimal structure retaining immunosuppressive activity was a truncated version of mycolactone, missing one of the two core-branched polyketide chains. This compound inhibited the inflammatory cytokine responses of human primary cells at noncytotoxic doses and bound to angiotensin II type 2 receptors comparably to mycolactone in vitro. Notably, it was considerably less toxic than mycolactone in human primary dermal fibroblasts modeling ulcerative activity. In mouse models of human diseases, it conferred systemic protection against chronic skin inflammation and inflammatory pain, with no apparent side effects. In addition to establishing the anti-inflammatory potency of mycolactone in vivo, our study therefore highlights the translational potential of mycolactone core-derived structures as prospective immunosuppressants.
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Affiliation(s)
- Laure Guenin-Macé
- Institut Pasteur, Unité d'Immunobiologie de l'Infection, Paris 75015, France. CNRS URA 1961, Paris 75015, France
| | - Ludivine Baron
- Institut Pasteur, Unité d'Immunobiologie de l'Infection, Paris 75015, France. CNRS URA 1961, Paris 75015, France
| | - Anne-Caroline Chany
- Université de Strasbourg, Laboratoire de Chimie Moléculaire, ECPM-CNRS UMR 7509, Strasbourg 67087, France
| | - Cédric Tresse
- Université de Strasbourg, Laboratoire de Chimie Moléculaire, ECPM-CNRS UMR 7509, Strasbourg 67087, France
| | - Sarah Saint-Auret
- Université de Strasbourg, Laboratoire de Chimie Moléculaire, ECPM-CNRS UMR 7509, Strasbourg 67087, France
| | - Friederike Jönsson
- Institut Pasteur, Unité Anticorps en Thérapie et Pathologie, Paris 75015, France. INSERM U760, Paris 75015, France
| | - Fabien Le Chevalier
- Institut Pasteur, Unité d'Immunobiologie de l'Infection, Paris 75015, France
| | - Pierre Bruhns
- Institut Pasteur, Unité Anticorps en Thérapie et Pathologie, Paris 75015, France. INSERM U760, Paris 75015, France
| | - Georges Bismuth
- INSERM U1016, Institut Cochin, Paris 75014, France. Université Paris Descartes, Paris 75014, France. CNRS UMR 8104, Paris 75014, France
| | - Sophie Hidalgo-Lucas
- ETAP, Inflammation, Dermatologie et Toxicologie, Vandœuvre-lès-Nancy 54500, France
| | - Jean-François Bisson
- ETAP, Inflammation, Dermatologie et Toxicologie, Vandœuvre-lès-Nancy 54500, France
| | - Nicolas Blanchard
- Université de Strasbourg, Laboratoire de Chimie Moléculaire, ECPM-CNRS UMR 7509, Strasbourg 67087, France
| | - Caroline Demangel
- Institut Pasteur, Unité d'Immunobiologie de l'Infection, Paris 75015, France. CNRS URA 1961, Paris 75015, France.
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30
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Brown CA, Aggarwal VK. Short Convergent Synthesis of the Mycolactone Core Through Lithiation-Borylation Homologations. Chemistry 2015; 21:13900-3. [PMID: 26332797 PMCID: PMC6519258 DOI: 10.1002/chem.201503122] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Indexed: 12/17/2022]
Abstract
Using iterative lithiation–borylation homologations, the mycolactone toxin core has been synthesized in 13 steps and 17 % overall yield. The rapid build‐up of molecular complexity, high convergence and high stereoselectivity are noteworthy features of this synthesis.
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Affiliation(s)
- Christopher A Brown
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS (UK)
| | - Varinder K Aggarwal
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS (UK).
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31
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Yotsu RR, Murase C, Sugawara M, Suzuki K, Nakanaga K, Ishii N, Asiedu K. Revisiting Buruli ulcer. J Dermatol 2015; 42:1033-41. [PMID: 26332541 DOI: 10.1111/1346-8138.13049] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Accepted: 06/23/2015] [Indexed: 11/27/2022]
Abstract
Buruli ulcer (BU), or Mycobacterium ulcerans infection, is a new emerging infectious disease which has been reported in over 33 countries worldwide. It has been noted not only in tropical areas, such as West Africa where it is most endemic, but also in moderate non-tropical climate areas, including Australia and Japan. Clinical presentation starts with a papule, nodule, plaque or edematous form which eventually leads to extensive skin ulceration. It can affect all age groups, but especially children aged between 5 and 15 years in West Africa. Multiple-antibiotic treatment has proven effective, and with surgical intervention at times of severity, it is curable. However, if diagnosis and treatment is delayed, those affected may be left with life-long disabilities. The disease is not yet fully understood, including its route of transmission and pathogenesis. However, due to recent research, several important features of the disease are now being elucidated. Notably, there may be undiagnosed cases in other parts of the world where BU has not yet been reported. Japan exemplifies the finding that awareness among dermatologists plays a key role in BU case detection. So, what about in other countries where a case of BU has never been diagnosed and there is no awareness of the disease among the population or, more importantly, among health professionals? This article will revisit BU, reviewing clinical features as well as the most recent epidemiological and scientific findings of the disease, to raise awareness of BU among dermatologists worldwide.
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Affiliation(s)
- Rie R Yotsu
- Department of Dermatology, National Suruga Sanatorium, Shizuoka, Japan.,Department of Dermatology, National Center for Global Health and Medicine, Tokyo, Japan
| | - Chiaki Murase
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | | | - Koichi Suzuki
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Tokyo, Japan.,Leprosy Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kazue Nakanaga
- Leprosy Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Norihisa Ishii
- Leprosy Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kingsley Asiedu
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
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Identification of Ser/Thr kinase and forkhead associated domains in Mycobacterium ulcerans: characterization of novel association between protein kinase Q and MupFHA. PLoS Negl Trop Dis 2014; 8:e3315. [PMID: 25412098 PMCID: PMC4238996 DOI: 10.1371/journal.pntd.0003315] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 10/04/2014] [Indexed: 11/24/2022] Open
Abstract
Background Mycobacterium ulcerans, the causative agent of Buruli ulcer in humans, is unique among the members of Mycobacterium genus due to the presence of the virulence determinant megaplasmid pMUM001. This plasmid encodes multiple virulence-associated genes, including mup011, which is an uncharacterized Ser/Thr protein kinase (STPK) PknQ. Methodology/Principal Findings In this study, we have characterized PknQ and explored its interaction with MupFHA (Mup018c), a FHA domain containing protein also encoded by pMUM001. MupFHA was found to interact with PknQ and suppress its autophosphorylation. Subsequent protein-protein docking and molecular dynamic simulation analyses showed that this interaction involves the FHA domain of MupFHA and PknQ activation loop residues Ser170 and Thr174. FHA domains are known to recognize phosphothreonine residues, and therefore, MupFHA may be acting as one of the few unusual FHA-domain having overlapping specificity. Additionally, we elucidated the PknQ-dependent regulation of MupDivIVA (Mup012c), which is a DivIVA domain containing protein encoded by pMUM001. MupDivIVA interacts with MupFHA and this interaction may also involve phospho-threonine/serine residues of MupDivIVA. Conclusions/Significance Together, these results describe novel signaling mechanisms in M. ulcerans and show a three-way regulation of PknQ, MupFHA, and MupDivIVA. FHA domains have been considered to be only pThr specific and our results indicate a novel mechanism of pSer as well as pThr interaction exhibited by MupFHA. These results signify the need of further re-evaluating the FHA domain –pThr/pSer interaction model. MupFHA may serve as the ideal candidate for structural studies on this unique class of modular enzymes. Mycobacterium ulcerans is a slow growing pathogen, which is prevalent in many tropical and sub-tropical countries. M. ulcerans possesses unique signaling pathways with only 13 STPK containing genes. This is strikingly different from its closest homolog Mycobacterium marinum and surprisingly closer to the human pathogen, Mycobacterium tuberculosis. PknQ, MupFHA and MupDivIVA are regulatory proteins encoded by the virulence determining plasmid pMUM001 of M. ulcerans. In addition to characterizing the STPK, we focused on deciphering the basis of interaction between the three partner proteins leading to the identification of critical residues. Present study describes the newly identified phosphoserine-based interactions, which is unique amongst the FHA-domain containing proteins. We confirmed our results using structural analysis via specific mutants and their interaction profiles. Importantly, these data highlight the significance of FHA domains and their role in understanding cellular signaling. This work will encourage further studies to elucidate role of M. ulcerans signaling systems. It will also raise questions like how less studied tropical bacterial pathogens acquire eukaryotic-like Ser/Thr protein kinase and exhibit unusual mechanisms to interact with its partner domains.
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Pleiotropic molecular effects of the Mycobacterium ulcerans virulence factor mycolactone underlying the cell death and immunosuppression seen in Buruli ulcer. Biochem Soc Trans 2014; 42:177-83. [PMID: 24450648 DOI: 10.1042/bst20130133] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mycolactone is a polyketide macrolide lipid-like secondary metabolite synthesized by Mycobacterium ulcerans, the causative agent of BU (Buruli ulcer), and is the only virulence factor for this pathogen identified to date. Prolonged exposure to high concentrations of mycolactone is cytotoxic to diverse mammalian cells (albeit with varying efficiency), whereas at lower doses it has a spectrum of immunosuppressive activities. Combined, these pleiotropic properties have a powerful influence on local and systemic cellular function that should explain the pathophysiology of BU disease. The last decade has seen significant advances in our understanding of the molecular mechanisms underlying these effects in a range of different cell types. The present review focuses on the current state of our knowledge of mycolactone function, and its molecular and cellular targets, and seeks to identify commonalities between the different functional and cellular systems. Since mycolactone influences fundamental cellular processes (cell division, cell death and inflammation), getting to the root of how mycolactone achieves this could have a profound impact on our understanding of eukaryotic cell biology.
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Mycobacterial toxin induces analgesia in buruli ulcer by targeting the angiotensin pathways. Cell 2014; 157:1565-76. [PMID: 24949969 DOI: 10.1016/j.cell.2014.04.040] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 04/01/2014] [Accepted: 04/24/2014] [Indexed: 01/09/2023]
Abstract
Mycobacterium ulcerans, the etiological agent of Buruli ulcer, causes extensive skin lesions, which despite their severity are not accompanied by pain. It was previously thought that this remarkable analgesia is ensured by direct nerve cell destruction. We demonstrate here that M. ulcerans-induced hypoesthesia is instead achieved through a specific neurological pathway triggered by the secreted mycobacterial polyketide mycolactone. We decipher this pathway at the molecular level, showing that mycolactone elicits signaling through type 2 angiotensin II receptors (AT2Rs), leading to potassium-dependent hyperpolarization of neurons. We further validate the physiological relevance of this mechanism with in vivo studies of pain sensitivity in mice infected with M. ulcerans, following the disruption of the identified pathway. Our findings shed new light on molecular mechanisms evolved by natural systems for the induction of very effective analgesia, opening up the prospect of new families of analgesics derived from such systems.
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35
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Chany AC, Veyron-Churlet R, Tresse C, Mayau V, Casarotto V, Le Chevalier F, Guenin-Macé L, Demangel C, Blanchard N. Synthetic variants of mycolactone bind and activate Wiskott-Aldrich syndrome proteins. J Med Chem 2014; 57:7382-95. [PMID: 25158122 DOI: 10.1021/jm5008819] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Mycolactone is a complex macrolide toxin produced by Mycobacterium ulcerans, the causative agent of skin lesions called Buruli ulcers. Mycolactone-mediated activation of neural (N) Wiskott-Aldrich syndrome proteins (WASP) induces defects in cell adhesion underpinning cytotoxicity and disease pathogenesis. We describe the chemical synthesis of 23 novel mycolactone analogues that differ in structure and modular assembly of the lactone core with its northern and southern polyketide side chains. The lactone core linked to southern chain was the minimal structure binding N-WASP and hematopoietic homolog WASP, where the number and configuration of hydroxyl groups on the acyl side chain impacted the degree of binding. A fluorescent derivative of this compound showed time-dependent accumulation in target cells. Furthermore, a simplified version of mycolactone mimicked the natural toxin for activation of WASP in vitro and induced comparable alterations of epithelial cell adhesion. Therefore, it constitutes a structural and functional surrogate of mycolactone for WASP/N-WASP-dependent effects.
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Affiliation(s)
- Anne-Caroline Chany
- Laboratoire de Chimie Organique et Bioorganique, Université de Haute-Alsace, ENSCMu , 3 Rue A. Werner, 68093 Mulhouse Cedex, France
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Drancourt M. Looking in amoebae as a source of mycobacteria. Microb Pathog 2014; 77:119-24. [PMID: 25017516 DOI: 10.1016/j.micpath.2014.07.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 07/01/2014] [Accepted: 07/03/2014] [Indexed: 11/16/2022]
Abstract
Mycobacteria exhibit various relationships with amoebae, ranging from the killing of one partner by the other one, to amoebae hosting mycobacteria in trophozoites and cysts. This observation indicates that poorly described biological factors affect the relationships, including mycobacterial cell-wall glycolipids and the size of the mycobacteria. Experimental observations indicate that a majority of environmental, opportunistic mycobacteria but also obligate pathogens including Mycobacterium tuberculosis, Mycobacterium leprae and Mycobacterium ulcerans are inter-amoebal organisms. Amoebae may give opportunities for genetic exchanges between mycobacteria, sympatric intra-amoebal organisms and the amoebae themselves. Amoebae clearly protect opportunistic mycobacterial pathogens during their environmental life but their role for obligate mycobacterial infection remains to be established. Accordingly, water was the source for emerging, community-acquired and health care-associated infection with amoeba-resisting mycobacteria of the Mycobacterium avium, Mycobacterium abscessus and Mycobacterium fortuitum groups, among others. Amoebae are organisms where mycobacteria can be found and, accordingly, amoeba co-culture can be used for the isolation of mycobacteria from environmental and clinical specimens. Looking in amoebae may help recovering new species of mycobacteria.
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Affiliation(s)
- M Drancourt
- Aix Marseille Université, URMITE, UM 63 UMR_S1095 UMR 7278, Méditerranée Infection, 13385, Marseille, France.
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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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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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Synthesis of the Conjugated Tetraene Acid Side Chain of Mycolactone E by Suzuki-Miyaura Cross-Coupling Reaction of Alkenyl Boronates. European J Org Chem 2013. [DOI: 10.1002/ejoc.201301484] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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40
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Kosa NM, Foley TL, Burkart MD. Fluorescent techniques for discovery and characterization of phosphopantetheinyl transferase inhibitors. J Antibiot (Tokyo) 2013; 67:113-20. [PMID: 24192555 DOI: 10.1038/ja.2013.106] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 08/26/2013] [Accepted: 09/13/2013] [Indexed: 11/09/2022]
Abstract
Phosphopantetheinyl transferase (PPTase; E.C. 2.7.8.-) activates biosynthetic pathways that synthesize both primary and secondary metabolites in bacteria. Inhibitors of these enzymes have the potential to serve as antibiotic compounds that function through a unique mode of action and possess clinical utility. Here we report a direct and continuous assay for this enzyme class based upon monitoring polarization of a fluorescent phosphopantetheine analog as it is transferred from a low-molecular weight CoA substrate to higher-molecular weight protein acceptor. We demonstrate the utility of this method for the biochemical characterization of PPTase Sfp, a canonical representative from this class. We also establish the portability of this technique to other homologs by adapting the assay to function with the human PPTase, a target for which a microplate detection method does not currently exist. Comparison of these targets provides a basis to predict the therapeutic index of inhibitor candidates and offers a valuable characterization of enzyme activity.
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Affiliation(s)
- Nicolas M Kosa
- Department of Chemistry and Biochemistry, University of California, San Diego (UCSD), La Jolla, CA, USA
| | - Timothy L Foley
- Department of Chemistry and Biochemistry, University of California, San Diego (UCSD), La Jolla, CA, USA
| | - Michael D Burkart
- Department of Chemistry and Biochemistry, University of California, San Diego (UCSD), La Jolla, CA, USA
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