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Treuner-Lange A, Zheng W, Viljoen A, Lindow S, Herfurth M, Dufrêne YF, Søgaard-Andersen L, Egelman EH. Tight-packing of large pilin subunits provides distinct structural and mechanical properties for the Myxococcus xanthus type IVa pilus. Proc Natl Acad Sci U S A 2024; 121:e2321989121. [PMID: 38625941 PMCID: PMC11046646 DOI: 10.1073/pnas.2321989121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 03/07/2024] [Indexed: 04/18/2024] Open
Abstract
Type IVa pili (T4aP) are ubiquitous cell surface filaments important for surface motility, adhesion to surfaces, DNA uptake, biofilm formation, and virulence. T4aP are built from thousands of copies of the major pilin subunit and tipped by a complex composed of minor pilins and in some systems also the PilY1 adhesin. While major pilins of structurally characterized T4aP have lengths of <165 residues, the major pilin PilA of Myxococcus xanthus is unusually large with 208 residues. All major pilins have a conserved N-terminal domain and a variable C-terminal domain, and the additional residues of PilA are due to a larger C-terminal domain. We solved the structure of the M. xanthus T4aP (T4aPMx) at a resolution of 3.0 Å using cryo-EM. The T4aPMx follows the structural blueprint of other T4aP with the pilus core comprised of the interacting N-terminal α1-helices, while the globular domains decorate the T4aP surface. The atomic model of PilA built into this map shows that the large C-terminal domain has more extensive intersubunit contacts than major pilins in other T4aP. As expected from these greater contacts, the bending and axial stiffness of the T4aPMx is significantly higher than that of other T4aP and supports T4aP-dependent motility on surfaces of different stiffnesses. Notably, T4aPMx variants with interrupted intersubunit interfaces had decreased bending stiffness, pilus length, and strongly reduced motility. These observations support an evolutionary scenario whereby the large major pilin enables the formation of a rigid T4aP that expands the environmental conditions in which the T4aP system functions.
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Affiliation(s)
- Anke Treuner-Lange
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg35043, Germany
| | - Weili Zheng
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA22903
| | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-NeuveB-1348, Belgium
| | - Steffi Lindow
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg35043, Germany
| | - Marco Herfurth
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg35043, Germany
| | - Yves F. Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-NeuveB-1348, Belgium
| | - Lotte Søgaard-Andersen
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg35043, Germany
| | - Edward H. Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA22903
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2
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Viljoen A, Dufrêne YF. Mechanobiology: How pathogens use mechanics to modulate host interactions. Cell 2023; 186:4994-4995. [PMID: 37949055 DOI: 10.1016/j.cell.2023.09.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 09/18/2023] [Accepted: 09/18/2023] [Indexed: 11/12/2023]
Abstract
Mechanobiology explores how cells sense and respond to mechanical cues and how mechanics guide cell function, physiology, and disease. In this issue of Cell, Thacker and colleagues reveal how the tuberculosis-causing pathogen exploits the mechanical behavior of cord-like structures to promote infection, impacting immune response, antibiotic susceptibility, and treatment strategies.
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Affiliation(s)
- Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium.
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium.
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3
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Treuner-Lange A, Zheng W, Viljoen A, Lindow S, Herfurth M, Dufrêne YF, Søgaard-Andersen L, Egelman EH. Large pilin subunits provide distinct structural and mechanical properties for the Myxococcus xanthus type IV pilus. bioRxiv 2023:2023.07.22.550172. [PMID: 37503255 PMCID: PMC10370171 DOI: 10.1101/2023.07.22.550172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Type IV pili (T4P) are ubiquitous bacterial cell surface filaments important for surface motility, adhesion to biotic and abiotic surfaces, DNA uptake, biofilm formation, and virulence. T4P are built from thousands of copies of the major pilin subunit and tipped by a complex composed of minor pilins and in some systems also the PilY1 adhesin. While the major pilins of structurally characterized T4P have lengths of up to 161 residues, the major pilin PilA of Myxococcus xanthus is unusually large with 208 residues. All major pilins have a highly conserved N-terminal domain and a highly variable C-terminal domain, and the additional residues in the M. xanthus PilA are due to a larger C-terminal domain. We solved the structure of the M. xanthus T4P (T4P Mx ) at a resolution of 3.0 Å using cryo-electron microscopy (cryo-EM). The T4P Mx follows the structural blueprint observed in other T4P with the pilus core comprised of the extensively interacting N-terminal α1-helices while the globular domains decorate the T4P surface. The atomic model of PilA built into this map shows that the large C-terminal domain has much more extensive intersubunit contacts than major pilins in other T4P. As expected from these greater contacts, the bending and axial stiffness of the T4P Mx is significantly higher than that of other T4P and supports T4P-dependent motility on surfaces of different stiffnesses. Notably, T4P Mx variants with interrupted intersubunit interfaces had decreased bending stiffness and strongly reduced motility on all surfaces. These observations support an evolutionary scenario whereby the large major pilin enables the formation of a rigid T4P that expands the environmental conditions in which the T4P system functions.
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4
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Viljoen A, Vercellone A, Chimen M, Gaibelet G, Mazères S, Nigou J, Dufrêne YF. Nanoscale clustering of mycobacterial ligands and DC-SIGN host receptors are key determinants for pathogen recognition. Sci Adv 2023; 9:eadf9498. [PMID: 37205764 PMCID: PMC10198640 DOI: 10.1126/sciadv.adf9498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 04/14/2023] [Indexed: 05/21/2023]
Abstract
The bacterial pathogen Mycobacterium tuberculosis binds to the C-type lectin DC-SIGN (dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin) on dendritic cells to evade the immune system. While DC-SIGN glycoconjugate ligands are ubiquitous among mycobacterial species, the receptor selectively binds pathogenic species from the M. tuberculosis complex (MTBC). Here, we unravel the molecular mechanism behind this intriguing selective recognition by means of a multidisciplinary approach combining single-molecule atomic force microscopy with Förster resonance energy transfer and bioassays. Molecular recognition imaging of mycobacteria demonstrates that the distribution of DC-SIGN ligands markedly differs between Mycobacterium bovis Bacille Calmette-Guérin (BCG) (model MTBC species) and Mycobacterium smegmatis (non-MTBC species), the ligands being concentrated into dense nanodomains on M. bovis BCG. Upon bacteria-host cell adhesion, ligand nanodomains induce the recruitment and clustering of DC-SIGN. Our study highlights the key role of clustering of both ligands on MTBC species and DC-SIGN host receptors in pathogen recognition, a mechanism that might be widespread in host-pathogen interactions.
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Affiliation(s)
- Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07., B-1348 Louvain-la-Neuve, Belgium
| | - Alain Vercellone
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UPS), Toulouse, France
| | - Myriam Chimen
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UPS), Toulouse, France
| | - Gérald Gaibelet
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UPS), Toulouse, France
| | - Serge Mazères
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UPS), Toulouse, France
| | - Jérôme Nigou
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UPS), Toulouse, France
| | - Yves F. Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07., B-1348 Louvain-la-Neuve, Belgium
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5
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Viljoen A, Oosthuizen MK. Dim light at night affects the locomotor activity of nocturnal African pygmy mice ( Mus minutoides) in an intensity-dependent manner. Proc Biol Sci 2023; 290:20230526. [PMID: 37072046 PMCID: PMC10113032 DOI: 10.1098/rspb.2023.0526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 03/27/2023] [Indexed: 04/20/2023] Open
Abstract
Rodents are integral components of ecosystems as they provide several important ecosystem services. Despite their importance as prey, pollinators and seed distributors, African rodents are largely understudied. The effect of anthropogenic changes such as artificial light at night extends past urban areas to peri-urban and rural habitats, and can have profound effects on entire ecosystems. We investigated the effect of dim light at night (dLAN) on the locomotor activity rhythms of the African pygmy mouse (Mus minutoides). Pygmy mice showed a dramatic, intensity-dependent reduction in their locomotor activity when subjected to dLAN, which was accompanied by a delay in the activity onset. We also considered masking responses with a dark pulse (DP) during the day and a light pulse at night. All animals became inactive in response to a light pulse during the night, whereas approximately half of the animals showed activity during a DP in the day. Our results suggest that the African pygmy mouse is highly sensitive to light and that their activity is strongly masked by light. In their natural environment, vegetation could shield pygmy mice against high light levels; however, other anthropogenic disturbances can alter the behaviour of these animals and could affect their survival.
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Affiliation(s)
- A. Viljoen
- Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
| | - M. K. Oosthuizen
- Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
- Mammal Research Institute, University of Pretoria, Pretoria 0002, South Africa
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6
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Wang C, Chantraine C, Viljoen A, Herr AB, Fey PD, Horswill AR, Mathelié-Guinlet M, Dufrêne YF. The staphylococcal biofilm protein Aap mediates cell-cell adhesion through mechanically distinct homophilic and lectin interactions. PNAS Nexus 2022; 1:pgac278. [PMID: 36712378 PMCID: PMC9802226 DOI: 10.1093/pnasnexus/pgac278] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 12/01/2022] [Indexed: 12/04/2022]
Abstract
The accumulation phase of staphylococcal biofilms relies on both the production of an extracellular polysaccharide matrix and the expression of bacterial surface proteins. A prototypical example of such adhesive proteins is the long multidomain protein Aap (accumulation-associated protein) from Staphylococcus epidermidis, which mediates zinc-dependent homophilic interactions between Aap B-repeat regions through molecular forces that have not been investigated yet. Here, we unravel the remarkable mechanical strength of single Aap-Aap homophilic bonds between living bacteria and we demonstrate that intercellular adhesion also involves sugar binding through the lectin domain of the Aap A region. We find that the mechanical force needed to unfold individual β-sheet-rich G5-E domains from the Aap B-repeat regions is very high, ranging from 300 up to 1,000 pN at high loading rates, indicating these are extremely stable. This high mechanostability provides a means to the cells to form highly adhesive and cohesive biofilms capable of sustaining high physiological shear stress. Importantly, we identify a previously undescribed role of Aap in bacterial-bacterial adhesion, that is, heterophilic sugar binding by a specific lectin domain located in the N-terminal A region, which might be important to establish initial contacts between cells before strong homophilic bonds come into play. This study emphasizes the remarkable mechanical and binding properties of Aap as well as its wide diversity of adhesive functions.
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Affiliation(s)
| | | | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Andrew B Herr
- Divisions of Immunobiology and Infectious Diseases, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Paul D Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA
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7
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Paiva T, Viljoen A, da Costa TM, Geoghegan JA, Dufrêne YF. Interaction of the Staphylococcus aureus Surface Protein FnBPB with Corneodesmosin Involves Two Distinct, Extremely Strong Bonds. ACS Nanosci Au 2022; 3:58-66. [PMID: 36820093 PMCID: PMC9936583 DOI: 10.1021/acsnanoscienceau.2c00036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/30/2022] [Accepted: 09/30/2022] [Indexed: 02/17/2023]
Abstract
Attachment of Staphylococcus aureus to human skin corneocyte cells plays a critical role in exacerbating the severity of atopic dermatitis (AD). Pathogen-skin adhesion is mediated by bacterial cell-surface proteins called adhesins, including fibronectin-binding protein B (FnBPB). FnBPB binds to corneodesmosin (CDSN), a glycoprotein exposed on AD patient corneocytes. Using single-molecule experiments, we demonstrate that CDSN binding by FnBPB relies on a sophisticated two-site mechanism. Both sites form extremely strong bonds with binding forces of ∼1 and ∼2.5 nN albeit with faster dissociation rates than those reported for homologues of the adhesin. This previously unidentified two-binding site interaction in FnBPB illustrates its remarkable variety of adhesive functions and is of biological significance as the high strength and short bond lifetime will favor efficient skin colonization by the pathogen.
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Affiliation(s)
- Telmo
O. Paiva
- Louvain
Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Albertus Viljoen
- Louvain
Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Thaina M. da Costa
- Department
of Microbiology, Moyne Institute of Preventive Medicine, School of
Genetics and Microbiology, Trinity College
Dublin, Dublin 2, Ireland
| | - Joan A. Geoghegan
- Department
of Microbiology, Moyne Institute of Preventive Medicine, School of
Genetics and Microbiology, Trinity College
Dublin, Dublin 2, Ireland,Institute
of Microbiology and Infection, University
of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.,
| | - Yves F. Dufrêne
- Louvain
Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, L7.07.07, B-1348 Louvain-la-Neuve, Belgium,
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8
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Clarke A, Bodini S, Douglas L, Catapano A, De Luca L, Hollstein T, Payne J, Pirro M, Viljoen A, Vogt A, Horne R. A behavioural science research programme to understand the barriers to achieving recommended LDL cholesterol goals. Atherosclerosis 2022. [DOI: 10.1016/j.atherosclerosis.2022.06.758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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9
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Viljoen A, Dufrêne YF. Force-induced unfolding of an antibiotic-bound outer-membrane protein. Structure 2022; 30:321-323. [PMID: 35245432 DOI: 10.1016/j.str.2022.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In this issue of Structure, Ritzmann et al. characterize the unfolding of the β-barrel assembly machinery component BamA with single-molecule force spectroscopy and reveal how an antibiotic changes BamA's mechanical properties and inhibits its activity. This work helps us understand the effects antibiotics have on Gram-negative outer membrane proteins.
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Affiliation(s)
- Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
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10
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Lipke PN, Rauceo JM, Viljoen A. Cell-Cell Mating Interactions: Overview and Potential of Single-Cell Force Spectroscopy. Int J Mol Sci 2022; 23:ijms23031110. [PMID: 35163034 PMCID: PMC8835621 DOI: 10.3390/ijms23031110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/08/2022] [Accepted: 01/14/2022] [Indexed: 02/01/2023] Open
Abstract
It is an understatement that mating and DNA transfer are key events for living organisms. Among the traits needed to facilitate mating, cell adhesion between gametes is a universal requirement. Thus, there should be specific properties for the adhesion proteins involved in mating. Biochemical and biophysical studies have revealed structural information about mating adhesins, as well as their specificities and affinities, leading to some ideas about these specialized adhesion proteins. Recently, single-cell force spectroscopy (SCFS) has added important findings. In SCFS, mating cells are brought into contact in an atomic force microscope (AFM), and the adhesive forces are monitored through the course of mating. The results have shown some remarkable characteristics of mating adhesins and add knowledge about the design and evolution of mating adhesins.
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Affiliation(s)
- Peter N. Lipke
- Biology Department, Brooklyn College of the City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA
- Correspondence: (P.N.L.); (A.V.)
| | - Jason M. Rauceo
- Department of Sciences, John Jay College of the City University of New York, New York, NY 10019, USA;
| | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4–5, bte L7.07.07, 1348 Louvain-la-Neuve, Belgium
- Correspondence: (P.N.L.); (A.V.)
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11
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Lipke PN, Mathelié-Guinlet M, Viljoen A, Dufrêne YF. A New Function for Amyloid-Like Interactions: Cross-Beta Aggregates of Adhesins form Cell-to-Cell Bonds. Pathogens 2021; 10:pathogens10081013. [PMID: 34451476 PMCID: PMC8398270 DOI: 10.3390/pathogens10081013] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/02/2021] [Accepted: 08/05/2021] [Indexed: 12/30/2022] Open
Abstract
Amyloid structures assemble through a repeating type of bonding called "cross-β", in which identical sequences in many protein molecules form β-sheets that interdigitate through side chain interactions. We review the structural characteristics of such bonds. Single cell force microscopy (SCFM) shows that yeast expressing Als5 adhesin from Candida albicans demonstrate the empirical characteristics of cross-β interactions. These properties include affinity for amyloid-binding dyes, birefringence, critical concentration dependence, repeating structure, and inhibition by anti-amyloid agents. We present a model for how cross-β bonds form in trans between two adhering cells. These characteristics also apply to other fungal adhesins, so the mechanism appears to be an example of a new type of cell-cell adhesion.
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Affiliation(s)
- Peter N. Lipke
- Biology Department, Brooklyn College of City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA
- Correspondence: ; Tel.: +1-(917)-696-4862
| | - Marion Mathelié-Guinlet
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium; (M.M.-G.); (A.V.); (Y.F.D.)
| | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium; (M.M.-G.); (A.V.); (Y.F.D.)
| | - Yves F. Dufrêne
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium; (M.M.-G.); (A.V.); (Y.F.D.)
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12
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Champciaux B, Raynaud C, Viljoen A, Chene L, Thibonnet J, Vincent SP, Kremer L, Thiery E. Synthesis and biological evaluation of 3,4-dihydro-1H-[1,4] oxazepino [6,5,4-hi] indol-1-ones and 4,6-dihydrooxepino [5,4,3-cd] indol-1(3H)-ones as Mycobacterium tuberculosis inhibitors. Bioorg Med Chem 2021; 43:116248. [PMID: 34274760 DOI: 10.1016/j.bmc.2021.116248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/13/2021] [Accepted: 05/28/2021] [Indexed: 11/16/2022]
Abstract
This study focuses on the synthesis of 1,7- and 3,4-indole-fused lactones via a simple and efficient reaction sequence. The functionalization of these "oxazepino-indole" and "oxepino-indole" tricycles is carried out by palladium catalysed CC coupling, nucleophilic substitution or 1,3-dipolar cycloaddition. The evaluation of their activity against Mycobacterium tuberculosis shows that the "oxazepino-indole" structure is a new inhibitor of M. tuberculosis growth in vitro.
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Affiliation(s)
- Bastien Champciaux
- Laboratoire Synthèse et Isolement de Molécules Bioactives (SIMBA, EA 7502), Université de Tours, Faculté de Pharmacie, Parc de Grandmont, 31 Avenue Monge, 37200 Tours, France
| | - Clément Raynaud
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS UMR 9004, Université de Montpellier, 34293 Montpellier, France
| | - Albertus Viljoen
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS UMR 9004, Université de Montpellier, 34293 Montpellier, France
| | - Loïc Chene
- Department of Chemistry, University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium
| | - Jérôme Thibonnet
- Laboratoire Synthèse et Isolement de Molécules Bioactives (SIMBA, EA 7502), Université de Tours, Faculté de Pharmacie, Parc de Grandmont, 31 Avenue Monge, 37200 Tours, France
| | - Stéphane P Vincent
- Department of Chemistry, University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium
| | - Laurent Kremer
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS UMR 9004, Université de Montpellier, 34293 Montpellier, France; INSERM, IRIM, 34293 Montpellier, France
| | - Emilie Thiery
- Laboratoire Synthèse et Isolement de Molécules Bioactives (SIMBA, EA 7502), Université de Tours, Faculté de Pharmacie, Parc de Grandmont, 31 Avenue Monge, 37200 Tours, France.
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13
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Mignolet J, Mathelié-Guinlet M, Viljoen A, Dufrêne YF. AFM force-clamp spectroscopy captures the nanomechanics of the Tad pilus retraction. Nanoscale Horiz 2021; 6:489-496. [PMID: 33982737 DOI: 10.1039/d1nh00158b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Motorization of bacterial pili is key to generate traction forces to achieve cellular function. The Tad (or Type IVc) pilus from Caulobacter crescentus is a widespread motorized nanomachine crucial for bacterial survival, evolution and virulence. An unusual bifunctional ATPase motor drives Tad pilus retraction, which helps the bacteria to land on target surfaces. Here, we use a novel platform combining a fluorescence-based screening of piliated bacteria and atomic force microscopy (AFM) force-clamp spectroscopy, to monitor over time (30 s) the nanomechanics and dynamics of the Tad nanofilament retraction under a high constant tension (300 pN). We observe striking transient variations of force and height originating from two phenomena: active pilus retraction and passive hydrophobic interactions between the pilus and the hydrophobic substrate. That the Tad pilus is able to retract under high tensile loading - at a velocity of ∼150 nm s-1 - indicates that this nanomachine is stronger than previously anticipated. Our findings show that pilus retraction and hydrophobic interactions work together to mediate bacterial cell landing and surface adhesion. The motorized pilus retraction actively triggers the cell to approach the substrate. At short distances, passive hydrophobic interactions accelerate the approach phenomenon and promote strong cell-substrate adhesion. This mechanism could provide a strategy to save ATP-based energy by the retraction ATPase. Our force-clamp AFM methodology offers promise to decipher the physics of bacterial nanomotors with high sensitivity and temporal resolution.
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Affiliation(s)
- Johann Mignolet
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte, L7.07.07, Louvain-la-Neuve B-1348, Belgium.
| | - Marion Mathelié-Guinlet
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte, L7.07.07, Louvain-la-Neuve B-1348, Belgium.
| | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte, L7.07.07, Louvain-la-Neuve B-1348, Belgium.
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte, L7.07.07, Louvain-la-Neuve B-1348, Belgium.
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Mignolet J, Viljoen A, Mathelié-Guinlet M, Viela F, Valotteau C, Dufrêne YF. AFM Unravels the Unique Adhesion Properties of the Caulobacter Type IVc Pilus Nanomachine. Nano Lett 2021; 21:3075-3082. [PMID: 33754731 DOI: 10.1021/acs.nanolett.1c00215] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Bacterial pili are proteinaceous motorized nanomachines that play various functional roles including surface adherence, bacterial motion, and virulence. The surface-contact sensor type IVc (or Tad) pilus is widely distributed in both Gram-positive and Gram-negative bacteria. In Caulobacter crescentus, this nanofilament, though crucial for surface colonization, has never been thoroughly investigated at the molecular level. As Caulobacter assembles several surface appendages at specific stages of the cell cycle, we designed a fluorescence-based screen to selectively study single piliated cells and combined it with atomic force microscopy and genetic manipulation to quantify the nanoscale adhesion of the type IVc pilus to hydrophobic substrates. We demonstrate that this nanofilament exhibits high stickiness compared to the canonical type IVa/b pili, resulting mostly from multiple hydrophobic interactions along the fiber length, and that it features nanospring mechanical properties. Our findings may be helpful to better understand the structure-function relationship of bacterial pilus nanomachines.
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Affiliation(s)
- Johann Mignolet
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte, L7.07.07., B-1348 Louvain-la-Neuve, Belgium
| | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte, L7.07.07., B-1348 Louvain-la-Neuve, Belgium
| | - Marion Mathelié-Guinlet
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte, L7.07.07., B-1348 Louvain-la-Neuve, Belgium
| | - Felipe Viela
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte, L7.07.07., B-1348 Louvain-la-Neuve, Belgium
| | - Claire Valotteau
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte, L7.07.07., B-1348 Louvain-la-Neuve, Belgium
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte, L7.07.07., B-1348 Louvain-la-Neuve, Belgium
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15
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Dufrêne YF, Viljoen A, Mignolet J, Mathelié-Guinlet M. AFM in cellular and molecular microbiology. Cell Microbiol 2021; 23:e13324. [PMID: 33710716 DOI: 10.1111/cmi.13324] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 12/14/2022]
Abstract
The unique capabilities of the atomic force microscope (AFM), including super-resolution imaging, piconewton force-sensitivity, nanomanipulation and ability to work under physiological conditions, have offered exciting avenues for cellular and molecular biology research. AFM imaging has helped unravel the fine architectures of microbial cell envelopes at the nanoscale, and how these are altered by antimicrobial treatment. Nanomechanical measurements have shed new light on the elasticity, tensile strength and turgor pressure of single cells. Single-molecule and single-cell force spectroscopy experiments have revealed the forces and dynamics of receptor-ligand interactions, the nanoscale distribution of receptors on the cell surface and the elasticity and adhesiveness of bacterial pili. Importantly, recent force spectroscopy studies have demonstrated that extremely stable bonds are formed between bacterial adhesins and their cognate ligands, originating from a catch bond behaviour allowing the pathogen to reinforce adhesion under shear or tensile stress. Here, we survey how the versatility of AFM has enabled addressing crucial questions in microbiology, with emphasis on bacterial pathogens. TAKE AWAYS: AFM topographic imaging unravels the ultrastructure of bacterial envelopes. Nanomechanical mapping shows what makes cell envelopes stiff and resistant to drugs. Force spectroscopy characterises the molecular forces in pathogen adhesion. Stretching pili reveals a wealth of mechanical and adhesive responses.
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Affiliation(s)
- Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Johann Mignolet
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Marion Mathelié-Guinlet
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
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16
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Daher W, Leclercq LD, Viljoen A, Karam J, Dufrêne YF, Guérardel Y, Kremer L. O-Methylation of the Glycopeptidolipid Acyl Chain Defines Surface Hydrophobicity of Mycobacterium abscessus and Macrophage Invasion. ACS Infect Dis 2020; 6:2756-2770. [PMID: 32857488 DOI: 10.1021/acsinfecdis.0c00490] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mycobacterium abscessus, an emerging pathogen responsible for severe lung infections in cystic fibrosis patients, displays either smooth (S) or rough (R) morphotypes. The S-to-R transition is associated with reduced levels of glycopeptidolipid (GPL) production and is correlated with increased pathogenicity in animal and human hosts. While the structure of GPL is well established, its biosynthetic pathway is incomplete. In addition, the biological functions of the distinct structural parts of this complex lipid remain elusive. Herein, the fmt gene encoding a putative O-methyltransferase was deleted in the M. abscessus S variant. Subsequent biochemical and structural analyses demonstrated that methoxylation of the fatty acyl chain of GPL was abrogated in the Δfmt mutant, and this defect was rescued upon complementation with a functional fmt gene. In contrast, the introduction of fmt derivatives mutated at residues essential for methyltransferase activity failed to complement GPL defects, indicating that fmt encodes an O-methyltransferase. Unexpectedly, phenotypic analyses showed that Δfmt was more hydrophilic than its parental progenitor, as demonstrated by hexadecane-aqueous buffer partitioning and atomic force microscopy experiments with hydrophobic probes. Importantly, the invasion rate of THP-1 macrophages by Δfmt was reduced by 50% when compared to the wild-type strain. Together, these results indicate that Fmt O-methylates the lipid moiety of GPL and plays a substantial role in conditioning the surface hydrophobicity of M. abscessus as well as in the early steps of the interaction between the bacilli and macrophages.
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Affiliation(s)
- Wassim Daher
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293 Montpellier, France
- INSERM, IRIM, 34293 Montpellier, France
| | - Louis-David Leclercq
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
| | - Albertus Viljoen
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293 Montpellier, France
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Jona Karam
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293 Montpellier, France
| | - Yves F. Dufrêne
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Yann Guérardel
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
| | - Laurent Kremer
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293 Montpellier, France
- INSERM, IRIM, 34293 Montpellier, France
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Hendriks SL, Viljoen A, Marais D, Wenhold FAM, McIntyre AM, Ngidi MS, Annandale JG, Kalaba M, Stewart D. Considerations for the design of nutrition-sensitive production programmes in rural South Africa. BMC Public Health 2020; 20:1383. [PMID: 32912223 PMCID: PMC7488396 DOI: 10.1186/s12889-020-09445-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 08/25/2020] [Indexed: 12/02/2022] Open
Abstract
Background Very little has been researched about the efficacy, effectiveness, feasibility, sustainability and impact of food-based approaches on the diets and nutritional status of populations at risk of hunger and food insecurity. This study contributes knowledge about the impact of food-based approaches on the diets of populations at risk of hunger and food insecurity in four of the poorest rural communities in South Africa. The study investigated the consumption and production patterns of rural households (278 in summer and 280 in winter) in four sites in the poorest municipalities in South Africa. Methods A multistage stratified random sampling technique was applied to identify the communities and sample households for the quantitative survey and qualitative assessments. Qualitative and quantitative data were collected between 2013 and 2015 through focus group discussions (FGDs), key informant interviews and the two-round panel survey to cover both the summer and winter seasons at each site. Results Home gardening led to a significant positive increase in the consumption of white roots and tubers, dark green leafy vegetables, orange-coloured fruit and other fruit in the 24 h prior to the survey. Participation in a community garden led to significant increases in the consumption of dark green leafy vegetables and other vegetables. School gardening did not demonstrate any statistical relationships with the consumption of foods from the crop-related food groups. Crop production improved dietary diversity. Selling produce and irrigation showed a stronger improvement in dietary diversity. Seasonality affected the availability of fresh fruit and vegetables for home consumption in winter. Conclusions Producing beyond that solely for home consumption has greater benefits for dietary diversity and a consumption-smoothing effect during the post-harvest period. Politicians and the scientific community should recognise the role that household and small-scale crop production plays in supporting household consumption and the provision of essential micronutrients despite constraints and disincentives. Production and education programmes should focus on strengthening existing good consumption patterns and promoting the consumption of foods that can improve dietary diversity.
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Affiliation(s)
- S L Hendriks
- Department of Agricultural Economics, Extension and Rural Development, University of Pretoria, PBag X01, Hatfield, Pretoria, 0028, South Africa.
| | - A Viljoen
- Department of Consumer Science, University of Pretoria, PBag X01, Hatfield, Pretoria, 0028, South Africa
| | - D Marais
- Department of Plant and Soil Sciences, University of Pretoria, PBag X01, Hatfield, Pretoria, 0028, South Africa
| | - F A M Wenhold
- Department of Human Nutrition, University of Pretoria, X323, Arcadia, Pretoria, 0007, South Africa
| | - A M McIntyre
- Department of Agricultural Economics, Extension and Rural Development, University of Pretoria, PBag X01, Hatfield, Pretoria, 0028, South Africa
| | - M S Ngidi
- Department of Agricultural Extension and Rural Resource Management, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, PBag01, Scottsville, 3209, South Africa
| | - J G Annandale
- Department of Plant and Soil Sciences, University of Pretoria, PBag X01, Hatfield, Pretoria, 0028, South Africa
| | - M Kalaba
- Department of Agricultural Economics, Extension and Rural Development, University of Pretoria, PBag X01, Hatfield, Pretoria, 0028, South Africa
| | - D Stewart
- Lima Rural Development Foundation, 2 Forrester's Lane, Pietermaritzburg, 3201, South Africa
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18
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Links S, van Zyl K, Cassiem A, Flett B, Viljoen A, Rose L. The association of maize characteristics with resistance to Fusarium verticillioides and fumonisin accumulation in commercial maize cultivars. WORLD MYCOTOXIN J 2020. [DOI: 10.3920/wmj2019.2537] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Fusarium verticillioides is the primary fungus that causes Fusarium ear rot (FER) of maize. Infection results in reduced grain yield and quality due to moulding and the contamination of grain with toxic compounds namely fumonisins. Resistance to fungal infection and fumonisin accumulation in maize and maize grain is governed at different levels. In this study, the structural, physico-chemical and genetic basis of resistance to F. verticillioides was investigated in two, replicated field trials at Potchefstroom and Vaalharts in South Africa. Phenotypic data (silk length, husk coverage, pericarp thickness hundred-kernel mass and kernel hardness), physico-chemical data (kernel pH, moisture content, total nitrogen and carbon as well as phenolic acid content) and the expression of pathogenesis-related-5 gene (PR5) and peroxidase gene expression was evaluated in 15 commercial cultivars under artificially inoculated and natural infection conditions. The data were correlated to FER severity, fumonisin accumulation and fungal DNA (referred to as infection indicators). Disease development and fumonisin contamination in Vaalharts was significantly more than in Potchefstroom. There were no significant correlations (r=≥0.60) between phenotypic characteristics and infection indicators. Kernel pH was the most important trait associated with disease development and was negatively correlated (between r=-0.58 and r=-0.75) to all infection indicators. PR5 gene expression had significant positive correlations (r=0.69 and r=0.72) with the fungal and fumonisin levels, respectively. This study presents of the first data demonstrating the use of gene expression in identifying FER/fumonisin-resistant plant material and could aid breeders and growers in selecting resistant material more effectively.
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Affiliation(s)
- S. Links
- Stellenbosch University, Faculty of AgriSciences, Stellenbosch, Matieland 7602, South Africa
- Grain SA, Research and Policy Centre, 457 Witherite Street, Willow Acres, Pretoria, 7600, South Africa
| | - K. van Zyl
- Stellenbosch University, Faculty of AgriSciences, Stellenbosch, Matieland 7602, South Africa
| | - A. Cassiem
- Stellenbosch University, Faculty of AgriSciences, Stellenbosch, Matieland 7602, South Africa
| | - B.C. Flett
- Agricultural Research Council, Grain Crops, Potchefstroom, 2520, South Africa
| | - A. Viljoen
- Stellenbosch University, Faculty of AgriSciences, Stellenbosch, Matieland 7602, South Africa
| | - L.J. Rose
- Stellenbosch University, Faculty of AgriSciences, Stellenbosch, Matieland 7602, South Africa
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Abstract
Bacterial pathogens are equipped with specialized surface-exposed proteins that bind strongly to ligands on host tissues and biomaterials. These adhesins play critical roles during infection, especially during the early step of adhesion where the cells are exposed to physical stress. Recent single-molecule experiments have shown that staphylococci interact with their ligands through a wide diversity of mechanosensitive molecular mechanisms. Adhesin-ligand interactions are activated by tensile force and can be ten times stronger than classical non-covalent biological bonds. Overall these studies demonstrate that Gram-positive adhesins feature unusual stress-dependent molecular interactions, which play essential roles during bacterial colonization and dissemination. With an increasing prevalence of multidrug resistant infections caused by Staphylococcus aureus and Staphylococcus epidermidis, chemotherapeutic targeting of adhesins offers an innovative alternative to antibiotics.
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Affiliation(s)
- Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, Catholic University of Louvain, Louvain-la-Neuve, Belgium
| | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, Catholic University of Louvain, Louvain-la-Neuve, Belgium
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20
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Viljoen A, Viela F, Kremer L, Dufrêne YF. Fast chemical force microscopy demonstrates that glycopeptidolipids define nanodomains of varying hydrophobicity on mycobacteria. Nanoscale Horiz 2020; 5:944-953. [PMID: 32314749 DOI: 10.1039/c9nh00736a] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Mycobacterium abscessus is an emerging multidrug-resistant bacterial pathogen causing severe lung infections in cystic fibrosis patients. A remarkable trait of this mycobacterial species is its ability to form morphologically smooth (S) and rough (R) colonies. The S-to-R transition is caused by the loss of glycopeptidolipids (GPLs) in the outer layer of the cell envelope and correlates with an increase in cording and virulence. Despite the physiological and medical importance of this morphological transition, whether it involves changes in cell surface properties remains unknown. Herein, we combine recently developed quantitative imaging (QI) atomic force microscopy (AFM) with hydrophobic tips to quantitatively map the surface structure and hydrophobicity of M. abscessus at high spatiotemporal resolution, and to assess how these properties are modulated by the S-to-R transition and by treatment with an inhibitor of the mycolic acid transporter MmpL3. We discover that loss of GPLs leads to major modifications in surface hydrophobicity, without any apparent change in cell surface ultrastructure. While R bacilli are homogeneously hydrophobic, S bacilli feature unusual variations of nanoscale hydrophobic properties. These previously undescribed cell surface nanodomains are likely to play critical roles in bacterial adhesion, aggregation, phenotypic heterogeneity and transmission, and in turn in virulence and pathogenicity. Our study also suggests that MmpL3 inhibitors show promise in nanomedicine as chemotherapeutic agents to interfere with the highly hydrophobic nature of the mycobacterial cell wall. The advantages of QI-AFM with hydrophobic tips are the ability to map chemical and structural properties simultaneously and at high resolution, applicable to a wide range of biosystems.
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Affiliation(s)
- Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium.
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21
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Viljoen A, Alsteens D, Dufrêne Y. Mechanical Forces between Mycobacterial Antigen 85 Complex and Fibronectin. Cells 2020; 9:cells9030716. [PMID: 32183296 PMCID: PMC7140604 DOI: 10.3390/cells9030716] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/09/2020] [Accepted: 03/13/2020] [Indexed: 12/27/2022] Open
Abstract
Adhesion to extracellular matrix proteins is an important first step in host invasion, employed by many bacterial pathogens. In mycobacteria, the secreted Ag85 complex proteins, involved in the synthesis of the cell envelope, are known to bind to fibronectin (Fn) through molecular forces that are currently unknown. In this study, single-molecule force spectroscopy is used to study the strength, kinetics and thermodynamics of the Ag85-Fn interaction, focusing on the multidrug-resistant Mycobacterium abscessus species. Single Ag85 proteins bind Fn with a strength of ~75 pN under moderate tensile loading, which compares well with the forces reported for other Fn-binding proteins. The binding specificity is demonstrated by using free Ag85 and Fn peptides with active binding sequences. The Ag85-Fn rupture force increases with mechanical stress (i.e., loading rate) according to the Friddle–Noy–de Yoreo theory. From this model, we extract thermodynamic parameters that are in good agreement with previous affinity determinations by surface plasmon resonance. Strong bonds (up to ~500 pN) are observed under high tensile loading, which may favor strong mycobacterial attachment in the lung where cells are exposed to high shear stress or during hematogenous spread which leads to a disseminated infection. Our results provide new insight into the pleiotropic functions of an important mycobacterial virulence factor that acts as a stress-sensitive adhesin.
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Affiliation(s)
- Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium; (A.V.); (D.A.)
| | - David Alsteens
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium; (A.V.); (D.A.)
- Walloon Excellence in Life sciences and Biotechnology (WELBIO), 1300 Wavre, Belgium
| | - Yves Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium; (A.V.); (D.A.)
- Walloon Excellence in Life sciences and Biotechnology (WELBIO), 1300 Wavre, Belgium
- Correspondence:
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22
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Shen L, Viljoen A, Villaume S, Joe M, Halloum I, Chêne L, Méry A, Fabre E, Takegawa K, Lowary TL, Vincent SP, Kremer L, Guérardel Y, Mariller C. The endogenous galactofuranosidase GlfH1 hydrolyzes mycobacterial arabinogalactan. J Biol Chem 2020; 295:5110-5123. [PMID: 32107309 DOI: 10.1074/jbc.ra119.011817] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 02/11/2020] [Indexed: 12/14/2022] Open
Abstract
Despite impressive progress made over the past 20 years in our understanding of mycolylarabinogalactan-peptidoglycan (mAGP) biogenesis, the mechanisms by which the tubercle bacillus Mycobacterium tuberculosis adapts its cell wall structure and composition to various environmental conditions, especially during infection, remain poorly understood. Being the central portion of the mAGP complex, arabinogalactan (AG) is believed to be the constituent of the mycobacterial cell envelope that undergoes the least structural changes, but no reports exist supporting this assumption. Herein, using recombinantly expressed mycobacterial protein, bioinformatics analyses, and kinetic and biochemical assays, we demonstrate that the AG can be remodeled by a mycobacterial endogenous enzyme. In particular, we found that the mycobacterial GlfH1 (Rv3096) protein exhibits exo-β-d-galactofuranose hydrolase activity and is capable of hydrolyzing the galactan chain of AG by recurrent cleavage of the terminal β-(1,5) and β-(1,6)-Galf linkages. The characterization of this galactosidase represents a first step toward understanding the remodeling of mycobacterial AG.
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Affiliation(s)
- Lin Shen
- Univ. Lille, CNRS, UMR8576 - UGSF - Unit[c33c]zpi;● de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
| | - Albertus Viljoen
- Institut de Recherche en Infectiologie de Montpellier (IRIM), UMR9004 - CNRS/UM, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Sydney Villaume
- Laboratoire de Chimie Bio-Organic (CBO), Université de Namur, rue de Bruxelles 61, 5000 Namur, Belgium
| | - Maju Joe
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton AB T6G 2G2, Canada
| | - Iman Halloum
- Institut de Recherche en Infectiologie de Montpellier (IRIM), UMR9004 - CNRS/UM, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Loïc Chêne
- Laboratoire de Chimie Bio-Organic (CBO), Université de Namur, rue de Bruxelles 61, 5000 Namur, Belgium
| | - Alexandre Méry
- Univ. Lille, CNRS, UMR8576 - UGSF - Unit[c33c]zpi;● de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
| | - Emeline Fabre
- Univ. Lille, CNRS, UMR8576 - UGSF - Unit[c33c]zpi;● de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
| | - Kaoru Takegawa
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Todd L Lowary
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton AB T6G 2G2, Canada
| | - Stéphane P Vincent
- Laboratoire de Chimie Bio-Organic (CBO), Université de Namur, rue de Bruxelles 61, 5000 Namur, Belgium
| | - Laurent Kremer
- Institut de Recherche en Infectiologie de Montpellier (IRIM), UMR9004 - CNRS/UM, 1919 route de Mende, 34293 Montpellier cedex 5, France.,INSERM, Institut de Recherche en Infectiologie de Montpellier, 34293 Montpellier, France
| | - Yann Guérardel
- Univ. Lille, CNRS, UMR8576 - UGSF - Unit[c33c]zpi;● de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
| | - Christophe Mariller
- Univ. Lille, CNRS, UMR8576 - UGSF - Unit[c33c]zpi;● de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
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23
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Viela F, Mathelié-Guinlet M, Viljoen A, Dufrêne YF. What makes bacterial pathogens so sticky? Mol Microbiol 2020; 113:683-690. [PMID: 31916325 DOI: 10.1111/mmi.14448] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/06/2020] [Indexed: 01/06/2023]
Abstract
Pathogenic bacteria use a variety of cell surface adhesins to promote binding to host tissues and protein-coated biomaterials, as well as cell-cell aggregation. These cellular interactions represent the first essential step that leads to host colonization and infection. Atomic force microscopy (AFM) has greatly contributed to increase our understanding of the specific interactions at play during microbial adhesion, down to the single-molecule level. A key asset of AFM is that adhesive interactions are studied under mechanical force, which is highly relevant as surface-attached pathogens are often exposed to physical stresses in the human body. These studies have identified sophisticated binding mechanisms in adhesins, which represent promising new targets for antiadhesion therapy.
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Affiliation(s)
- Felipe Viela
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Marion Mathelié-Guinlet
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium.,Walloon Excellence in Life sciences and Biotechnology (WELBIO), Wavre, Belgium
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Kimunye JN, Were E, Mussa F, Tazuba A, Jomanga K, Viljoen A, Swennen R, Muthoni FK, Mahuku G. Distribution of Pseudocercospora species causing Sigatoka leaf diseases of banana in Uganda and Tanzania. Plant Pathol 2020; 69:50-59. [PMID: 31894162 PMCID: PMC6919302 DOI: 10.1111/ppa.13105] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/25/2019] [Accepted: 09/29/2019] [Indexed: 05/31/2023]
Abstract
Sigatoka leaf diseases are a major constraint to banana production. A survey was conducted in Tanzania and Uganda to assess the distribution of Pseudocercospora species and severity of Sigatoka leaf diseases. Pseudocercospora species were identified using species-specific primers. Sigatoka-like leaf diseases were observed in all farms and on all cultivars, but disease severity varied significantly (P < 0.001) between countries, districts/regions within countries, altitudinal ranges and banana cultivars. In all regions except Kilimanjaro, P. fijiensis, the causal agent of black Sigatoka, was the only pathogen associated with Sigatoka disease. Mycosphaerella musae was associated with Sigatoka-like symptoms in Kilimanjaro region. Black Sigatoka disease was more severe in Uganda, with a mean disease severity index (DSI) of 37.5%, than in Tanzania (DSI = 19.9%). In Uganda, black Sigatoka disease was equally severe in Luwero district (mean DSI = 40.4%) and Mbarara district (mean DSI = 37.9%). In Tanzania, black Sigatoka was most severe in Kagera region (mean DSI = 29.2%) and least in Mbeya region (mean DSI = 11.5%). Pseudocercospora fijiensis, the most devastating sigatoka pathogen, was detected at altitudes of up to 1877 m a.s.l. This range expansion of P. fijiensis, previously confined to altitudes lower than 1350 m a.s.l. in East Africa, is of concern, especially for smallholder banana farmers growing the susceptible East African Highland bananas (EAHB). Among the banana varieties sampled, the EAHB, FHIA hybrids and Mchare were the most susceptible. Here, the loss of resistance in Yangambi KM5, a banana variety previously resistant to P. fijiensis, is reported for the first time.
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Affiliation(s)
- J. N. Kimunye
- International Institute of Tropical Agriculture, PO Box 7878, Kampala, Uganda
- Department of Plant Pathology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
| | - E. Were
- International Institute of Tropical Agriculture, PO Box 7878, Kampala, Uganda
| | - F. Mussa
- International Institute of Tropical Agriculture (IITA), Dar es Salaam, PO Box 34441, Tanzania
| | - A. Tazuba
- International Institute of Tropical Agriculture, PO Box 7878, Kampala, Uganda
| | - K. Jomanga
- International Institute of Tropical Agriculture (IITA), c/o Nelson Mandela African Institution of Science and Technology, Nelson Mandela Road, Arusha, Tanzania
| | - A. Viljoen
- International Institute of Tropical Agriculture (IITA), Dar es Salaam, PO Box 34441, Tanzania
| | - R. Swennen
- International Institute of Tropical Agriculture (IITA), c/o Nelson Mandela African Institution of Science and Technology, Nelson Mandela Road, Arusha, Tanzania
- Laboratory of Tropical Crop Improvement, KU Leuven, Willem De Croylaan 42, 3001 Leuven, Belgium
| | | | - G. Mahuku
- International Institute of Tropical Agriculture, PO Box 7878, Kampala, Uganda
- International Institute of Tropical Agriculture (IITA), Dar es Salaam, PO Box 34441, Tanzania
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Mathelié-Guinlet M, Viela F, Viljoen A, Dehullu J, Dufrêne YF. Single-molecule atomic force microscopy studies of microbial pathogens. Current Opinion in Biomedical Engineering 2019. [DOI: 10.1016/j.cobme.2019.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Kharsany K, Viljoen A, Leonard C, van Vuuren S. The new buzz: Investigating the antimicrobial interactions between bioactive compounds found in South African propolis. J Ethnopharmacol 2019; 238:111867. [PMID: 30978456 DOI: 10.1016/j.jep.2019.111867] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/04/2019] [Accepted: 04/04/2019] [Indexed: 06/09/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Propolis, a resinous substance produced by the Apis mellifera bee, contains a number of flavonoids sourced from plants found in the surrounding region. Whilst bees use this substance to seal off and protect the beehive, humans have used propolis therapeutically for centuries, making use of its antibacterial, antiseptic, antipyretic and wound healing properties, among others. South African propolis is rich in the flavonoids pinocembrin, galangin, and chrysin and very little previous research has been conducted on the antimicrobial effects of these compounds. AIM OF THE STUDY To obtain an understanding of the antimicrobial activity of the compounds pinocembrin, galangin, and chrysin, both independently and in combination. MATERIALS AND METHODS The compounds pinocembrin, galangin and chrysin were investigated for interactive antimicrobial activity by determining the minimum inhibitory concentrations (MIC), minimum bactericidal concentrations (MBC), anti-quorum sensing activity, biofilm studies, and toxicity studies (brine shrimp lethality assay). RESULTS Minimum inhibitory concentration results demonstrated that combinations of compounds showed better inhibitory activity than single compounds. When the flavonoids were tested in combination using the MIC assay, synergy was noted for 22% of the 1:1 ratio combinations and for 66% of the triple 1:1:1 ratio combinations. Similarly, MBC results showed bactericidal activity from selected combinations, while the compounds on their own demonstrated no cidal activity. Quorum sensing studies showed that compound combinations are more effective at inhibiting bacterial communication than the individual compounds. Biofilm assays showed that the highest percentage inhibition was observed for the triple combination against E. coli at 24 h. Finally, brine shrimp lethality studies revealed that combinations of the three compounds had reduced cytotoxicity when compared to the individual compounds. CONCLUSION The results obtained in this study demonstrate that the compounds found in South African propolis work synergistically to achieve an optimal antimicrobial effect, whilst simultaneously minimizing cytotoxicity.
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Affiliation(s)
- K Kharsany
- Department of Pharmacy and Pharmacology, Faculty of Health Science, University of the Witwatersrand, 7 York Road, Parktown, 2193, South Africa
| | - A Viljoen
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa; SAMRC Herbal Drugs Research Unit, Department of Pharmaceutical Sciences, Tshwane University of Technology, Pretoria, South Africa
| | - C Leonard
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
| | - S van Vuuren
- Department of Pharmacy and Pharmacology, Faculty of Health Science, University of the Witwatersrand, 7 York Road, Parktown, 2193, South Africa.
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Santucci P, Johansen MD, Point V, Poncin I, Viljoen A, Cavalier JF, Kremer L, Canaan S. Nitrogen deprivation induces triacylglycerol accumulation, drug tolerance and hypervirulence in mycobacteria. Sci Rep 2019; 9:8667. [PMID: 31209261 PMCID: PMC6572852 DOI: 10.1038/s41598-019-45164-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 05/29/2019] [Indexed: 11/09/2022] Open
Abstract
Mycobacteria share with other actinomycetes the ability to produce large quantities of triacylglycerol (TAG), which accumulate as intracytoplasmic lipid inclusions (ILI) also known as lipid droplets (LD). Mycobacterium tuberculosis (M. tb), the etiologic agent of tuberculosis, acquires fatty acids from the human host which are utilized to synthesize TAG, subsequently stored in the form of ILI to meet the carbon and nutrient requirements of the bacterium during long periods of persistence. However, environmental factors governing mycobacterial ILI formation and degradation remain poorly understood. Herein, we demonstrated that in the absence of host cells, carbon excess and nitrogen starvation promote TAG accumulation in the form of ILI in M. smegmatis and M. abscessus, used as surrogate species of M. tb. Based on these findings, we developed a simple and reversible in vitro model to regulate ILI biosynthesis and hydrolysis in mycobacteria. We also showed that TAG formation is tgs1 dependent and that lipolytic enzymes mediate TAG breakdown. Moreover, we confirmed that the nitrogen-deprived and ILI-rich phenotype was associated with an increased tolerance towards several drugs used for treating mycobacterial infections. Importantly, we showed that the presence of ILI substantially enhanced the bacterial burden and granuloma abundance in zebrafish embryos infected with lipid-rich M. abscessus as compared to embryos infected with lipid-poor M. abscessus, suggesting that ILI are actively contributing to mycobacterial virulence and pathogenesis.
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Affiliation(s)
- Pierre Santucci
- Aix-Marseille Univ, CNRS, LISM, IMM FR3479, Marseille, France
| | - Matt D Johansen
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, UMR 9004, Université de Montpellier, 34293, Montpellier, France
| | - Vanessa Point
- Aix-Marseille Univ, CNRS, LISM, IMM FR3479, Marseille, France
| | - Isabelle Poncin
- Aix-Marseille Univ, CNRS, LISM, IMM FR3479, Marseille, France
| | - Albertus Viljoen
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, UMR 9004, Université de Montpellier, 34293, Montpellier, France
| | | | - Laurent Kremer
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, UMR 9004, Université de Montpellier, 34293, Montpellier, France.,INSERM, IRIM, 34293, Montpellier, France
| | - Stéphane Canaan
- Aix-Marseille Univ, CNRS, LISM, IMM FR3479, Marseille, France.
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Le Moigne V, Bernut A, Cortès M, Viljoen A, Dupont C, Pawlik A, Gaillard JL, Misguich F, Crémazy F, Kremer L, Herrmann JL. Lsr2 Is an Important Determinant of Intracellular Growth and Virulence in Mycobacterium abscessus. Front Microbiol 2019; 10:905. [PMID: 31114557 PMCID: PMC6503116 DOI: 10.3389/fmicb.2019.00905] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 04/09/2019] [Indexed: 12/30/2022] Open
Abstract
Mycobacterium abscessus, a pathogen responsible for severe lung infections in cystic fibrosis patients, exhibits either smooth (S) or rough (R) morphotypes. The S-to-R transition correlates with inhibition of the synthesis and/or transport of glycopeptidolipids (GPLs) and is associated with an increase of pathogenicity in animal and human hosts. Lsr2 is a small nucleoid-associated protein highly conserved in mycobacteria, including M. abscessus, and is a functional homolog of the heat-stable nucleoid-structuring protein (H-NS). It is essential in Mycobacterium tuberculosis but not in the non-pathogenic model organism Mycobacterium smegmatis. It acts as a master transcriptional regulator of multiple genes involved in virulence and immunogenicity through binding to AT-rich genomic regions. Previous transcriptomic studies, confirmed here by quantitative PCR, showed increased expression of lsr2 (MAB_0545) in R morphotypes when compared to their S counterparts, suggesting a possible role of this protein in the virulence of the R form. This was addressed by generating lsr2 knock-out mutants in both S (Δlsr2-S) and R (Δlsr2-R) variants, demonstrating that this gene is dispensable for M. abscessus growth. We show that the wild-type S variant, Δlsr2-S and Δlsr2-R strains were more sensitive to H2O2 as compared to the wild-type R variant of M. abscessus. Importantly, virulence of the Lsr2 mutants was considerably diminished in cellular models (macrophage and amoeba) as well as in infected animals (mouse and zebrafish). Collectively, these results emphasize the importance of Lsr2 in M. abscessus virulence.
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Affiliation(s)
| | - Audrey Bernut
- UMR 9004, Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
| | | | - Albertus Viljoen
- UMR 9004, Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
| | - Christian Dupont
- UMR 9004, Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
| | - Alexandre Pawlik
- Unité de Pathogénomique Mycobactérienne, Institut Pasteur, Paris, France
| | - Jean-Louis Gaillard
- 2I, UVSQ, INSERM, Université Paris-Saclay, Versailles, France.,APHP, GHU PIFO, Hôpital Raymond-Poincaré - Hôpital Ambroise-Paré, Boulogne-Billancourt, France
| | | | | | - Laurent Kremer
- UMR 9004, Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France.,INSERM, Institut de Recherche en Infectiologie de Montpellier, Montpellier, France
| | - Jean-Louis Herrmann
- 2I, UVSQ, INSERM, Université Paris-Saclay, Versailles, France.,APHP, GHU PIFO, Hôpital Raymond-Poincaré - Hôpital Ambroise-Paré, Boulogne-Billancourt, France
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29
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Rani A, Viljoen A, Johansen MD, Kremer L, Kumar V. Synthesis, anti-mycobacterial and cytotoxic evaluation of substituted isoindoline-1,3-dione-4-aminoquinolines coupled via alkyl/amide linkers. RSC Adv 2019; 9:8515-8528. [PMID: 35518673 PMCID: PMC9061829 DOI: 10.1039/c8ra10532d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 03/03/2019] [Indexed: 01/19/2023] Open
Abstract
A series of secondary amine-substituted isoindoline-1,3-dione-4-aminoquinolines were prepared via microwave heating and assayed for their anti-mycobacterial activities. The compound with a butyl chain as a spacer between the two pharmacophores and piperidine as the secondary amine component on the isoindoline ring was the most potent and non-cytotoxic among the synthesized compounds, exhibiting a minimum inhibitory concentration (MIC99) of 6.25 μg mL−1 against Mycobacterium tuberculosis. A series of secondary amine-substituted isoindoline-1,3-dione-4-aminoquinolines were prepared via microwave heating and assayed for their anti-mycobacterial activities.![]()
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Affiliation(s)
- Anu Rani
- Department of Chemistry
- Guru Nanak Dev University
- Amritsar-143005
- India
| | - Albertus Viljoen
- Institut de Recherche en Infectiologie (IRIM) de Montpellier
- CNRS
- UMR 9004 Université de Montpellier
- France
| | - Matt D. Johansen
- Institut de Recherche en Infectiologie (IRIM) de Montpellier
- CNRS
- UMR 9004 Université de Montpellier
- France
| | - Laurent Kremer
- Institut de Recherche en Infectiologie (IRIM) de Montpellier
- CNRS
- UMR 9004 Université de Montpellier
- France
- INSERM
| | - Vipan Kumar
- Department of Chemistry
- Guru Nanak Dev University
- Amritsar-143005
- India
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30
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Dubois V, Viljoen A, Laencina L, Le Moigne V, Bernut A, Dubar F, Blaise M, Gaillard JL, Guérardel Y, Kremer L, Herrmann JL, Girard-Misguich F. MmpL8 MAB controls Mycobacterium abscessus virulence and production of a previously unknown glycolipid family. Proc Natl Acad Sci U S A 2018; 115:E10147-E10156. [PMID: 30301802 PMCID: PMC6205491 DOI: 10.1073/pnas.1812984115] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Mycobacterium abscessus is a peculiar rapid-growing Mycobacterium (RGM) capable of surviving within eukaryotic cells thanks to an arsenal of virulence genes also found in slow-growing mycobacteria (SGM), such as Mycobacterium tuberculosis A screen based on the intracellular survival in amoebae and macrophages (MΦ) of an M. abscessus transposon mutant library revealed the important role of MAB_0855, a yet uncharacterized Mycobacterial membrane protein Large (MmpL). Large-scale comparisons with SGM and RGM genomes uncovered MmpL12 proteins as putative orthologs of MAB_0855 and a locus-scale synteny between the MAB_0855 and Mycobacterium chelonae mmpL8 loci. A KO mutant of the MAB_0855 gene, designated herein as mmpL8MAB , had impaired adhesion to MΦ and displayed a decreased intracellular viability. Despite retaining the ability to block phagosomal acidification, like the WT strain, the mmpL8MAB mutant was delayed in damaging the phagosomal membrane and in making contact with the cytosol. Virulence attenuation of the mutant was confirmed in vivo by impaired zebrafish killing and a diminished propensity to induce granuloma formation. The previously shown role of MmpL in lipid transport prompted us to investigate the potential lipid substrates of MmpL8MAB Systematic lipid analysis revealed that MmpL8MAB was required for the proper expression of a glycolipid entity, a glycosyl diacylated nonadecyl diol (GDND) alcohol comprising different combinations of oleic and stearic acids. This study shows the importance of MmpL8MAB in modifying interactions between the bacteria and phagocytic cells and in the production of a previously unknown glycolipid family.
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Affiliation(s)
- Violaine Dubois
- Université de Versailles Saint Quentin en Yvelines, INSERM UMR1173, 78000 Versailles, France
| | - Albertus Viljoen
- CNRS UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, 34293 Montpellier, France
| | - Laura Laencina
- Université de Versailles Saint Quentin en Yvelines, INSERM UMR1173, 78000 Versailles, France
| | - Vincent Le Moigne
- Université de Versailles Saint Quentin en Yvelines, INSERM UMR1173, 78000 Versailles, France
| | - Audrey Bernut
- CNRS UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, 34293 Montpellier, France
| | - Faustine Dubar
- Université de Lille, CNRS UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle, 59000 Lille, France
| | - Mickaël Blaise
- CNRS UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, 34293 Montpellier, France
| | - Jean-Louis Gaillard
- Université de Versailles Saint Quentin en Yvelines, INSERM UMR1173, 78000 Versailles, France
- Assistance Publique-Hôpitaux de Paris, Groupement Hospitalier Universitaire Paris Ile de France Ouest, Hôpital Raymond Poincaré, Hôpital Ambroise Paré, 92380 Garches, Boulogne Billancourt, France
| | - Yann Guérardel
- Université de Lille, CNRS UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle, 59000 Lille, France
| | - Laurent Kremer
- CNRS UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, 34293 Montpellier, France
- INSERM, Institut de Recherche en Infectiologie de Montpellier, 34293 Montpellier, France
| | - Jean-Louis Herrmann
- Université de Versailles Saint Quentin en Yvelines, INSERM UMR1173, 78000 Versailles, France;
- Assistance Publique-Hôpitaux de Paris, Groupement Hospitalier Universitaire Paris Ile de France Ouest, Hôpital Raymond Poincaré, Hôpital Ambroise Paré, 92380 Garches, Boulogne Billancourt, France
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31
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Singh A, Viljoen A, Kremer L, Kumar V. Synthesis and Antimycobacterial Evaluation of Piperazyl-alkyl-Ether Linked 7-Chloroquinoline-Chalcone/Ferrocenyl Chalcone Conjugates. ChemistrySelect 2018. [DOI: 10.1002/slct.201801453] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Amandeep Singh
- Department of Chemistry; Guru Nanak Dev University; Amritsar-143005, Punjab India
| | - Albertus Viljoen
- Institut de Recherche en Infectiologie (IRIM), CNRS, UMR 9004, Université de Montpellier, ; France
| | - Laurent Kremer
- Institut de Recherche en Infectiologie (IRIM), CNRS, UMR 9004, Université de Montpellier, ; France
- INSERM, IRIM; 34293 Montpellier France
| | - Vipan Kumar
- Department of Chemistry; Guru Nanak Dev University; Amritsar-143005, Punjab India
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32
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Wierzbicki A, Viljoen A, Viljoen S, Martin S, Crook M, Reynolds T. Review of referral criteria to lipid clinics and outcomes of treatment in 4 UK centres. Atherosclerosis 2018. [DOI: 10.1016/j.atherosclerosis.2018.06.756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Gutiérrez AV, Viljoen A, Ghigo E, Herrmann JL, Kremer L. Glycopeptidolipids, a Double-Edged Sword of the Mycobacterium abscessus Complex. Front Microbiol 2018; 9:1145. [PMID: 29922253 PMCID: PMC5996870 DOI: 10.3389/fmicb.2018.01145] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/14/2018] [Indexed: 01/14/2023] Open
Abstract
Mycobacterium abscessus is a rapidly-growing species causing a diverse panel of clinical manifestations, ranging from cutaneous infections to severe respiratory disease. Its unique cell wall, contributing largely to drug resistance and to pathogenicity, comprises a vast panoply of complex lipids, among which the glycopeptidolipids (GPLs) have been the focus of intense research. These lipids fulfill various important functions, from sliding motility or biofilm formation to interaction with host cells and intramacrophage trafficking. Being highly immunogenic, the induction of a strong humoral response is likely to select for rough low-GPL producers. These, in contrast to the smooth high-GPL producers, display aggregative properties, which strongly impacts upon intracellular survival. A propensity to grow as extracellular cords allows these low-GPL producing bacilli to escape the innate immune defenses. Transitioning from high-GPL to low-GPL producers implicates mutations within genes involved in biosynthesis or transport of GPL. This leads to induction of an intense pro-inflammatory response and robust and lethal infections in animal models, explaining the presence of rough isolates in patients with decreased pulmonary functions. Herein, we will discuss how, thanks to the generation of defined GPL mutants and the development of appropriate cellular and animal models to study pathogenesis, GPL contribute to M. abscessus biology and physiopathology.
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Affiliation(s)
- Ana Victoria Gutiérrez
- Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, UMR 9004, Université de Montpellier, Montpellier, France.,CNRS, IRD 198, INSERM U1095, APHM, Institut Hospitalo-Universitaire Méditerranée Infection, UMR 7278, Aix-Marseille Université, Marseille, France
| | - Albertus Viljoen
- Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, UMR 9004, Université de Montpellier, Montpellier, France
| | - Eric Ghigo
- CNRS, Campus Joseph Aiguier, Marseille, France
| | | | - Laurent Kremer
- Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, UMR 9004, Université de Montpellier, Montpellier, France.,INSERM, IRIM, Montpellier, France
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34
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Gratwick Z, Donnellan C, Page PC, Viljoen A, Williams J, Lyle CH. Caecal intussusceptions and typhlocolitis in horses with severe Gastrodiscus aegyptiacusinfestation. EQUINE VET EDUC 2018. [DOI: 10.1111/eve.12726] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Z. Gratwick
- Department of Companion Animal Clinical Studies; University of Pretoria; Onderstepoort South Africa
| | - C. Donnellan
- Blue Cross Veterinary Hospital; Cape Town South Africa
| | - P. C. Page
- Department of Companion Animal Clinical Studies; University of Pretoria; Onderstepoort South Africa
| | - A. Viljoen
- Department of Companion Animal Clinical Studies; University of Pretoria; Onderstepoort South Africa
| | - J. Williams
- Department of Paraclinical Studies; University of Pretoria; Onderstepoort South Africa
| | - C. H. Lyle
- Department of Companion Animal Clinical Studies; University of Pretoria; Onderstepoort South Africa
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35
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Küssau T, Flipo M, Van Wyk N, Viljoen A, Olieric V, Kremer L, Blaise M. Structural rearrangements occurring upon cofactor binding in the Mycobacterium smegmatis β-ketoacyl-acyl carrier protein reductase MabA. Acta Crystallogr D Struct Biol 2018; 74:383-393. [PMID: 29717709 DOI: 10.1107/s2059798318002917] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 02/19/2018] [Indexed: 12/14/2022]
Abstract
In mycobacteria, the ketoacyl-acyl carrier protein (ACP) reductase MabA (designated FabG in other bacteria) catalyzes the NADPH-dependent reduction of β-ketoacyl-ACP substrates to β-hydroxyacyl-ACP products. This first reductive step in the fatty-acid biosynthesis elongation cycle is essential for bacteria, which makes MabA/FabG an interesting drug target. To date, however, very few molecules targeting FabG have been discovered and MabA remains the only enzyme of the mycobacterial type II fatty-acid synthase that lacks specific inhibitors. Despite the existence of several MabA/FabG crystal structures, the structural rearrangement that occurs upon cofactor binding is still not fully understood. Therefore, unlocking this knowledge gap could help in the design of new inhibitors. Here, high-resolution crystal structures of MabA from Mycobacterium smegmatis in its apo, NADP+-bound and NADPH-bound forms are reported. Comparison of these crystal structures reveals the structural reorganization of the lid region covering the active site of the enzyme. The crystal structure of the apo form revealed numerous residues that trigger steric hindrance to the binding of NADPH and substrate. Upon NADPH binding, these residues are pushed away from the active site, allowing the enzyme to adopt an open conformation. The transition from an NADPH-bound to an NADP+-bound form is likely to facilitate release of the product. These results may be useful for subsequent rational drug design and/or for in silico drug-screening approaches targeting MabA/FabG.
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Affiliation(s)
- Tanja Küssau
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS UMR 9004, 34293 Montpellier, France
| | - Marion Flipo
- Université de Lille, INSERM, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, 59000 Lille, France
| | - Niel Van Wyk
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS UMR 9004, 34293 Montpellier, France
| | - Albertus Viljoen
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS UMR 9004, 34293 Montpellier, France
| | - Vincent Olieric
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Laurent Kremer
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS UMR 9004, 34293 Montpellier, France
| | - Mickaël Blaise
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS UMR 9004, 34293 Montpellier, France
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Viljoen A, Gutiérrez AV, Dupont C, Ghigo E, Kremer L. A Simple and Rapid Gene Disruption Strategy in Mycobacterium abscessus: On the Design and Application of Glycopeptidolipid Mutants. Front Cell Infect Microbiol 2018; 8:69. [PMID: 29594066 PMCID: PMC5861769 DOI: 10.3389/fcimb.2018.00069] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 02/27/2018] [Indexed: 12/12/2022] Open
Abstract
Little is known about the disease-causing genetic determinants that are used by Mycobacterium abscessus, increasingly acknowledged as an important emerging pathogen, notably in cystic fibrosis. The presence or absence of surface exposed glycopeptidolipids (GPL) conditions the smooth (S) or rough (R) M. abscessus subsp. abscessus (M. abscessus) variants, respectively, which are characterized by distinct infective programs. However, only a handful of successful gene knock-out and conditional mutants have been reported in M. abscessus, testifying that genetic manipulation of this mycobacterium is difficult. To facilitate gene disruption and generation of conditional mutants in M. abscessus, we have designed a one-step single cross-over system that allows the rapid and simple generation of such mutants. Cloning of as small as 300 bp of the target gene allows for efficient homologous recombination to occur without additional exogenous recombination-promoting factors. The presence of tdTomato on the plasmids allows easily sifting out the large background of mutants spontaneously resistant to antibiotics. Using this strategy in the S genetic background and the target gene mmpL4a, necessary for GPL synthesis and transport, nearly 100% of red fluorescent clones exhibited a rough morphotype and lost GPL on the surface, suggesting that most red fluorescent colonies obtained after transformation incorporated the plasmid through homologous recombination into the chromosome. This system was further exploited to generate another strain with reduced GPL levels to explore how the presence of these cell wall-associated glycolipids influences M. abscessus hydrophobicity as well as virulence in the zebrafish model of infection. This mutant exhibited a more pronounced killing phenotype in zebrafish embryos compared to its S progenitor and this effect correlated with the production of abscesses in the central nervous system. Overall, these results suggest that the near-complete absence of GPL on the bacterial surface is a necessary condition for optimal pathogenesis of this mycobacterium. They also suggest that GPL content affects hydrophobicity of M. abscessus, potentially altering the aerosol transmission, which is of particular importance from an epidemiological and clinical perspective.
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Affiliation(s)
- Albertus Viljoen
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
| | - Ana Victoria Gutiérrez
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
- Unité de Recherche Microbes, Evolution, Phylogeny and Infection (MEPHI), Institut Hospitalier Universitaire Méditerranée-Infection, Marseille, France
| | - Christian Dupont
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
| | - Eric Ghigo
- Centre National de la Recherche Scientifique, Marseille, France
| | - Laurent Kremer
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
- IRIM, 34293, Institut National de la Santé et de la Recherche Médicale, Montpellier, France
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Laencina L, Dubois V, Le Moigne V, Viljoen A, Majlessi L, Pritchard J, Bernut A, Piel L, Roux AL, Gaillard JL, Lombard B, Loew D, Rubin EJ, Brosch R, Kremer L, Herrmann JL, Girard-Misguich F. Identification of genes required for Mycobacterium abscessus growth in vivo with a prominent role of the ESX-4 locus. Proc Natl Acad Sci U S A 2018; 115:E1002-E1011. [PMID: 29343644 PMCID: PMC5798338 DOI: 10.1073/pnas.1713195115] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mycobacterium abscessus, a rapidly growing mycobacterium (RGM) and an opportunistic human pathogen, is responsible for a wide spectrum of clinical manifestations ranging from pulmonary to skin and soft tissue infections. This intracellular organism can resist the bactericidal defense mechanisms of amoebae and macrophages, an ability that has not been observed in other RGM. M. abscessus can up-regulate several virulence factors during transient infection of amoebae, thereby becoming more virulent in subsequent respiratory infections in mice. Here, we sought to identify the M. abscessus genes required for replication within amoebae. To this end, we constructed and screened a transposon (Tn) insertion library of an M. abscessus subspecies massiliense clinical isolate for attenuated clones. This approach identified five genes within the ESX-4 locus, which in M. abscessus encodes an ESX-4 type VII secretion system that exceptionally also includes the ESX conserved EccE component. To confirm the screening results and to get further insight into the contribution of ESX-4 to M. abscessus growth and survival in amoebae and macrophages, we generated a deletion mutant of eccB4 that encodes a core structural element of ESX-4. This mutant was less efficient at blocking phagosomal acidification than its parental strain. Importantly, and in contrast to the wild-type strain, it also failed to damage phagosomes and showed reduced signs of phagosome-to-cytosol contact, as demonstrated by a combination of cellular and immunological assays. This study attributes an unexpected and genuine biological role to the underexplored mycobacterial ESX-4 system and its substrates.
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Affiliation(s)
- Laura Laencina
- Université de Versailles Saint Quentin en Yvelines, INSERM UMR1173, 78000 Versailles, France
| | - Violaine Dubois
- Université de Versailles Saint Quentin en Yvelines, INSERM UMR1173, 78000 Versailles, France
| | - Vincent Le Moigne
- Université de Versailles Saint Quentin en Yvelines, INSERM UMR1173, 78000 Versailles, France
| | - Albertus Viljoen
- Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, CNRS UMR 9004, 34293 Montpellier, France
| | - Laleh Majlessi
- Unité de Pathogénomique Mycobactérienne, Institut Pasteur, 75015 Paris, France
| | - Justin Pritchard
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA 02115
| | - Audrey Bernut
- Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, CNRS UMR 9004, 34293 Montpellier, France
| | - Laura Piel
- Université de Versailles Saint Quentin en Yvelines, INSERM UMR1173, 78000 Versailles, France
| | - Anne-Laure Roux
- Université de Versailles Saint Quentin en Yvelines, INSERM UMR1173, 78000 Versailles, France
- Assistance Publique-Hôpitaux de Paris, Hôpitaux Universitaires Ile de France Ouest, Ambroise Paré, Boulogne and Raymond Poincaré, 92380 Garches, France
| | - Jean-Louis Gaillard
- Université de Versailles Saint Quentin en Yvelines, INSERM UMR1173, 78000 Versailles, France
- Assistance Publique-Hôpitaux de Paris, Hôpitaux Universitaires Ile de France Ouest, Ambroise Paré, Boulogne and Raymond Poincaré, 92380 Garches, France
| | - Bérengère Lombard
- Laboratoire de spectrométrie de masse protéomique, Institut Curie, Paris Science and Letters Research University, 75248 Paris, France
| | - Damarys Loew
- Laboratoire de spectrométrie de masse protéomique, Institut Curie, Paris Science and Letters Research University, 75248 Paris, France
| | - Eric J Rubin
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA 02115
| | - Roland Brosch
- Unité de Pathogénomique Mycobactérienne, Institut Pasteur, 75015 Paris, France
| | - Laurent Kremer
- Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, CNRS UMR 9004, 34293 Montpellier, France
- INSERM, Institut de Recherche en Infectiologie de Montpellier, 34293 Montpellier, France
| | - Jean-Louis Herrmann
- Université de Versailles Saint Quentin en Yvelines, INSERM UMR1173, 78000 Versailles, France;
- Assistance Publique-Hôpitaux de Paris, Hôpitaux Universitaires Ile de France Ouest, Ambroise Paré, Boulogne and Raymond Poincaré, 92380 Garches, France
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Viljoen A, Richard M, Nguyen PC, Fourquet P, Camoin L, Paudal RR, Gnawali GR, Spilling CD, Cavalier JF, Canaan S, Blaise M, Kremer L. Cyclipostins and cyclophostin analogs inhibit the antigen 85C from Mycobacterium tuberculosis both in vitro and in vivo. J Biol Chem 2018; 293:2755-2769. [PMID: 29301937 DOI: 10.1074/jbc.ra117.000760] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 12/05/2017] [Indexed: 12/27/2022] Open
Abstract
An increasing prevalence of cases of drug-resistant tuberculosis requires the development of more efficacious chemotherapies. We previously reported the discovery of a new class of cyclipostins and cyclophostin (CyC) analogs exhibiting potent activity against Mycobacterium tuberculosis both in vitro and in infected macrophages. Competitive labeling/enrichment assays combined with MS have identified several serine or cysteine enzymes in lipid and cell wall metabolism as putative targets of these CyC compounds. These targets included members of the antigen 85 (Ag85) complex (i.e. Ag85A, Ag85B, and Ag85C), responsible for biosynthesis of trehalose dimycolate and mycolylation of arabinogalactan. Herein, we used biochemical and structural approaches to validate the Ag85 complex as a pharmacological target of the CyC analogs. We found that CyC7β, CyC8β, and CyC17 bind covalently to the catalytic Ser124 residue in Ag85C; inhibit mycolyltransferase activity (i.e. the transfer of a fatty acid molecule onto trehalose); and reduce triacylglycerol synthase activity, a property previously attributed to Ag85A. Supporting these results, an X-ray structure of Ag85C in complex with CyC8β disclosed that this inhibitor occupies Ag85C's substrate-binding pocket. Importantly, metabolic labeling of M. tuberculosis cultures revealed that the CyC compounds impair both trehalose dimycolate synthesis and mycolylation of arabinogalactan. Overall, our study provides compelling evidence that CyC analogs can inhibit the activity of the Ag85 complex in vitro and in mycobacteria, opening the door to a new strategy for inhibiting Ag85. The high-resolution crystal structure obtained will further guide the rational optimization of new CyC scaffolds with greater specificity and potency against M. tuberculosis.
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Affiliation(s)
- Albertus Viljoen
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS UMR9004, 34293 Montpellier, France
| | - Matthias Richard
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS UMR9004, 34293 Montpellier, France
| | - Phuong Chi Nguyen
- Aix-Marseille Université, CNRS, EIPL, IMM FR3479, 13009 Marseille, France; Aix-Marseille Université, CNRS, LISM, IMM FR3479, 13009 Marseille, France
| | - Patrick Fourquet
- Aix Marseille Université, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, Marseille Protéomique, 13009 Marseille, France
| | - Luc Camoin
- Aix Marseille Université, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, Marseille Protéomique, 13009 Marseille, France
| | - Rishi R Paudal
- Department of Chemistry and Biochemistry, University of Missouri, St. Louis, Missouri 63121
| | - Giri R Gnawali
- Department of Chemistry and Biochemistry, University of Missouri, St. Louis, Missouri 63121
| | - Christopher D Spilling
- Department of Chemistry and Biochemistry, University of Missouri, St. Louis, Missouri 63121
| | - Jean-François Cavalier
- Aix-Marseille Université, CNRS, EIPL, IMM FR3479, 13009 Marseille, France; Aix-Marseille Université, CNRS, LISM, IMM FR3479, 13009 Marseille, France
| | - Stéphane Canaan
- Aix-Marseille Université, CNRS, EIPL, IMM FR3479, 13009 Marseille, France; Aix-Marseille Université, CNRS, LISM, IMM FR3479, 13009 Marseille, France
| | - Mickael Blaise
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS UMR9004, 34293 Montpellier, France.
| | - Laurent Kremer
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS UMR9004, 34293 Montpellier, France; INSERM, IRIM, 34293 Montpellier, France.
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Rani A, Viljoen A, Sumanjit, Kremer L, Kumar V. Microwave-Assisted Highly Efficient Route to 4-Aminoquinoline-Phthalimide Conjugates: Synthesis and Anti-Tubercular Evaluation. ChemistrySelect 2017. [DOI: 10.1002/slct.201702220] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Anu Rani
- Department of Chemistry; Guru Nanak Dev University; Amritsar- 143005 India
| | - Albertus Viljoen
- Institut de Recherche en Infectiologie (IRIM); CNRS, UMR 9004; Université de Montpellier; France
| | - Sumanjit
- Department of Chemistry; Guru Nanak Dev University; Amritsar- 143005 India
| | - Laurent Kremer
- Institut de Recherche en Infectiologie (IRIM); CNRS, UMR 9004; Université de Montpellier; France
- INSERM, IRIM; 34293 Montpellier France
| | - Vipan Kumar
- Department of Chemistry; Guru Nanak Dev University; Amritsar- 143005 India
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Roux AL, Viljoen A, Bah A, Simeone R, Bernut A, Laencina L, Deramaudt T, Rottman M, Gaillard JL, Majlessi L, Brosch R, Girard-Misguich F, Vergne I, de Chastellier C, Kremer L, Herrmann JL. The distinct fate of smooth and rough Mycobacterium abscessus variants inside macrophages. Open Biol 2017; 6:rsob.160185. [PMID: 27906132 PMCID: PMC5133439 DOI: 10.1098/rsob.160185] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 10/31/2016] [Indexed: 02/07/2023] Open
Abstract
Mycobacterium abscessus is a pathogenic, rapidly growing mycobacterium responsible for pulmonary and cutaneous infections in immunocompetent patients and in patients with Mendelian disorders, such as cystic fibrosis (CF). Mycobacterium abscessus is known to transition from a smooth (S) morphotype with cell surface-associated glycopeptidolipids (GPL) to a rough (R) morphotype lacking GPL. Herein, we show that M. abscessus S and R variants are able to grow inside macrophages and are present in morphologically distinct phagosomes. The S forms are found mostly as single bacteria within phagosomes characterized by a tightly apposed phagosomal membrane and the presence of an electron translucent zone (ETZ) surrounding the bacilli. By contrast, infection with the R form leads to phagosomes often containing more than two bacilli, surrounded by a loose phagosomal membrane and lacking the ETZ. In contrast to the R variant, the S variant is capable of restricting intraphagosomal acidification and induces less apoptosis and autophagy. Importantly, the membrane of phagosomes enclosing the S forms showed signs of alteration, such as breaks or partial degradation. Although not frequently encountered, these events suggest that the S form is capable of provoking phagosome-cytosol communication. In conclusion, M. abscessus S exhibits traits inside macrophages that are reminiscent of slow-growing mycobacterial species.
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Affiliation(s)
- Anne-Laure Roux
- UMR1173, Inserm and UFR Des Sciences de la Santé Simone Veil, Université de Versailles Saint Quentin, Montigny, France
| | - Albertus Viljoen
- Centre National de la Recherche Scientifique FRE 3689, Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé, Université de Montpellier, 1919, Route de Mende, 34293, Montpellier, France.,Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université UM 2, Inserm, U1104, CNRS UMR7280, 13288, Marseille, France
| | - Aïcha Bah
- CNRS, Institut de Pharmacologie et de Biologie Structurale (IPBS), UMR 5089 CNRS/Université Paul Sabatier, 205 route de Narbonne, BP 64182, 31077 Toulouse Cedex 4, France
| | - Roxane Simeone
- Unité de Pathogénomique mycobactérienne, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, Paris, France
| | - Audrey Bernut
- Centre National de la Recherche Scientifique FRE 3689, Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé, Université de Montpellier, 1919, Route de Mende, 34293, Montpellier, France
| | - Laura Laencina
- UMR1173, Inserm and UFR Des Sciences de la Santé Simone Veil, Université de Versailles Saint Quentin, Montigny, France
| | - Therese Deramaudt
- UMR1179, Inserm and UFR Des Sciences de la Santé Simone Veil, Université de Versailles Saint Quentin, Montigny, France
| | - Martin Rottman
- UMR1173, Inserm and UFR Des Sciences de la Santé Simone Veil, Université de Versailles Saint Quentin, Montigny, France
| | - Jean-Louis Gaillard
- UMR1173, Inserm and UFR Des Sciences de la Santé Simone Veil, Université de Versailles Saint Quentin, Montigny, France
| | - Laleh Majlessi
- Unité de Pathogénomique mycobactérienne, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, Paris, France
| | - Roland Brosch
- Unité de Pathogénomique mycobactérienne, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, Paris, France
| | - Fabienne Girard-Misguich
- UMR1173, Inserm and UFR Des Sciences de la Santé Simone Veil, Université de Versailles Saint Quentin, Montigny, France
| | - Isabelle Vergne
- CNRS, Institut de Pharmacologie et de Biologie Structurale (IPBS), UMR 5089 CNRS/Université Paul Sabatier, 205 route de Narbonne, BP 64182, 31077 Toulouse Cedex 4, France
| | - Chantal de Chastellier
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université UM 2, Inserm, U1104, CNRS UMR7280, 13288, Marseille, France
| | - Laurent Kremer
- Centre National de la Recherche Scientifique FRE 3689, Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé, Université de Montpellier, 1919, Route de Mende, 34293, Montpellier, France .,INSERM, CPBS, 34293 Montpellier, France
| | - Jean-Louis Herrmann
- UMR1173, Inserm and UFR Des Sciences de la Santé Simone Veil, Université de Versailles Saint Quentin, Montigny, France
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Leonard C, Chen W, van Vuuren S, Viljoen A. Exploring the phytochemical variation of the “Pepper-bark” tree (Warburgia salutaris) using HPTLC and UPLC-MS. Am J Transl Res 2017. [DOI: 10.1055/s-0037-1608527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- C Leonard
- Department of Pharmaceutical Sciences, Faculty of Science, Tshwane University of Technology, Pretoria, South Africa
| | - W Chen
- Department of Pharmaceutical Sciences, Faculty of Science, Tshwane University of Technology, Pretoria, South Africa
| | - S van Vuuren
- Department of Pharmacy and Pharmacology, University of Witwatersrand, Johannesburg, South Africa
| | - A Viljoen
- Department of Pharmaceutical Sciences, Faculty of Science, Tshwane University of Technology, Pretoria, South Africa
- SAMRC Herbal Drugs Research Unit, Faculty of Science, Tshwane University of Technology, Pretoria, South Africa
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Mncwangi N, Waltenberger B, Baraldo G, Jansen-Dürr P, Viljoen A, Stuppner H. Sclerocarya birrea cortex ethanolic extract – Chemical characterisation and NOX4 inhibition (anti-ageing property). Am J Transl Res 2017. [DOI: 10.1055/s-0037-1608258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- N Mncwangi
- 1. Department of Pharmaceutical Sciences and SAMRC Herbal Drugs Research Unit, Tshwane University of Technology, Private Bag X680, Pretoria, South Africa
| | - B Waltenberger
- 2. Institute of Pharmacy/Pharmacognosy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80 – 20, 6020, Innsbruck, Austria
| | - G Baraldo
- 3. Institute for Biomedical Aging Research and CMBI, University of Innsbruck, Rennweg 10, 6020, Innsbruck, Austria
| | - P Jansen-Dürr
- 3. Institute for Biomedical Aging Research and CMBI, University of Innsbruck, Rennweg 10, 6020, Innsbruck, Austria
| | - A Viljoen
- 1. Department of Pharmaceutical Sciences and SAMRC Herbal Drugs Research Unit, Tshwane University of Technology, Private Bag X680, Pretoria, South Africa
| | - H Stuppner
- 2. Institute of Pharmacy/Pharmacognosy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80 – 20, 6020, Innsbruck, Austria
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Komane B, Viljoen A, Vermaak I, Kamatou G, Summers B. Cosmetic application of Marula seed oil (Sclerocarya birrea): Clinical outcomes. Am J Transl Res 2017. [DOI: 10.1055/s-0037-1608569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- B Komane
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa, Pretoria, South Africa
| | - A Viljoen
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa, Pretoria, South Africa
| | - I Vermaak
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa, Pretoria, South Africa
| | - G Kamatou
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa, Pretoria, South Africa
| | - B Summers
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa, Pretoria, South Africa
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44
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Sandasi M, Chen W, Viljoen A. Identification and quantification of herbal tea blend raw materials using hyperspectral imaging spectroscopy. Am J Transl Res 2017. [DOI: 10.1055/s-0037-1608526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- M Sandasi
- Department of Pharmaceutical Sciences Tshwane University of Technology, Private Bag X680, Pretoria, South Africa
| | - W Chen
- Department of Pharmaceutical Sciences Tshwane University of Technology, Private Bag X680, Pretoria, South Africa
| | - A Viljoen
- Department of Pharmaceutical Sciences Tshwane University of Technology, Private Bag X680, Pretoria, South Africa
- SAMRC Herbal Drugs Research Unit, Tshwane University of Technology, Private Bag X680, Pretoria, South Africa
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45
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Vermaak I, Tankeu S, Djokam M, Sandasi M, Chen W, Viljoen A. Hyperspectral imaging in combination with chemometric data analysis – a novel approach in the quality control of herbal material. Am J Transl Res 2017. [DOI: 10.1055/s-0037-1608585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- I Vermaak
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Pretoria, South Africa
- SAMRC Herbal Drugs Research Unit, Tshwane University of Technology, Pretoria, South Africa
| | - S Tankeu
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Pretoria, South Africa
| | - M Djokam
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Pretoria, South Africa
| | - M Sandasi
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Pretoria, South Africa
| | - W Chen
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Pretoria, South Africa
| | - A Viljoen
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Pretoria, South Africa
- SAMRC Herbal Drugs Research Unit, Tshwane University of Technology, Pretoria, South Africa
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46
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Aboobaker Z, van Vuuren S, Viljoen A, Crous P. South African endophytes- potential antimicrobial agents. Am J Transl Res 2017. [DOI: 10.1055/s-0037-1608034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Z Aboobaker
- Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, 2193, Parktown, South Africa
| | - S van Vuuren
- Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, 2193, Parktown, South Africa
| | - A Viljoen
- Department of Pharmaceutical Sciences, Faculty of Sciences, Tshwane University of Technology, Private Bag X680, 0001, Pretoria, South Africa
| | - P Crous
- Westerdijk Fungal Biodiversity Institute, P.O. Box 85167, 3508 AD, Utrecht, Netherlands
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Viljoen A, Herrmann JL, Onajole OK, Stec J, Kozikowski AP, Kremer L. Controlling Extra- and Intramacrophagic Mycobacterium abscessus by Targeting Mycolic Acid Transport. Front Cell Infect Microbiol 2017; 7:388. [PMID: 28920054 PMCID: PMC5585149 DOI: 10.3389/fcimb.2017.00388] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 08/21/2017] [Indexed: 12/20/2022] Open
Abstract
Mycobacterium abscessus is a rapidly growing mycobacterium (RGM) causing serious infections especially among cystic fibrosis patients. Extremely limited therapeutic options against M. abscessus and a rise in infections with this mycobacterium require novel chemotherapies and a better understanding of how the bacterium causes infection. Different from most RGM, M. abscessus can survive inside macrophages and persist for long durations in infected tissues. We recently delineated differences in the infective programs followed by smooth (S) and rough (R) variants of M. abscessus. Unexpectedly, we found that the S variant behaves like pathogenic slow growing mycobacteria, through maintaining a block on the phagosome maturation process and by inducing phagosome-cytosol communications. On the other hand, R variant infection triggers autophagy and apoptosis, reminiscent of the way that macrophages control RGM. However, the R variant has an exquisite capacity to form extracellular cords, allowing these bacteria to rapidly divide and evade phagocytosis. Therefore, new chemotherapeutic interventions against M. abscessus need to efficiently deal with both the reservoir of intracellular bacilli and the extracellular cords. In this context, we recently identified two chemical entities that were very effective against both M. abscessus populations. Although being structurally unrelated these two chemotypes inhibit the activity of the essential mycolic acid transporter, MmpL3. In this Perspective, we aimed to highlight recent insights into how M. abscessus interacts with phagocytic cells and how the inhibition of mycolic acid transport in this pathogenic RGM could be an efficient means to control both intracellular and extracellular populations of the bacterium.
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Affiliation(s)
- Albertus Viljoen
- Centre National de la Recherche Scientifique UMR9004, Institut de Recherche en Infectiologie de Montpellier, Université de MontpellierMontpellier, France
| | - Jean-Louis Herrmann
- UMR1173, INSERM and UFR Des Sciences de la Santé Simone Veil, Université de Versailles Saint QuentinMontigny-le-Bretonneux, France
| | - Oluseye K Onajole
- Department of Biological, Chemical and Physical Sciences, Roosevelt UniversityChicago, IL, United States
| | - Jozef Stec
- Department of Pharmaceutical Sciences, College of Pharmacy, Marshall B. Ketchum UniversityFullerton, CA, United States
| | - Alan P Kozikowski
- StarWise Therapeutics LLC, University Research ParkMadison, WI, United States
| | - Laurent Kremer
- Centre National de la Recherche Scientifique UMR9004, Institut de Recherche en Infectiologie de Montpellier, Université de MontpellierMontpellier, France.,INSERM, IRIM, 34293Montpellier, France
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Kozikowski AP, Onajole OK, Stec J, Dupont C, Viljoen A, Richard M, Chaira T, Lun S, Bishai W, Raj VS, Ordway D, Kremer L. Targeting Mycolic Acid Transport by Indole-2-carboxamides for the Treatment of Mycobacterium abscessus Infections. J Med Chem 2017; 60:5876-5888. [PMID: 28574259 DOI: 10.1021/acs.jmedchem.7b00582] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Mycobacterium abscessus is a fast-growing, multidrug-resistant organism that has emerged as a clinically significant pathogen in cystic fibrosis (CF) patients. The intrinsic resistance of M. abscessus to most commonly available antibiotics seriously restricts chemotherapeutic options. Herein, we report the potent activity of a series of indolecarboxamides against M. abscessus. The lead compounds, 6 and 12, exhibited strong activity in vitro against a wide panel of M. abscessus isolates and in infected macrophages. High resistance levels to the indolecarboxamides appear to be associated with an A309P mutation in the mycolic acid transporter MmpL3. Biochemical analyses demonstrated that while de novo mycolic acid synthesis remained unaffected, the indolecarboxamides strongly inhibited the transport of trehalose monomycolate, resulting in the loss of trehalose dimycolate production and abrogating mycolylation of arabinogalactan. Our data introduce a hereto unexploited chemical structure class active against M. abscessus infections with promising translational development possibilities for the treatment of CF patients.
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Affiliation(s)
- Alan P Kozikowski
- Drug Discovery Program, Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago , 833 South Wood Street, Chicago, Illinois 60612, United States
| | - Oluseye K Onajole
- Drug Discovery Program, Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago , 833 South Wood Street, Chicago, Illinois 60612, United States.,Department of Biological, Chemical and Physical Sciences, Roosevelt University , 425 South Wabash Avenue, Chicago, Illinois 60605, United States
| | - Jozef Stec
- Department of Pharmaceutical Sciences, College of Pharmacy, Chicago State University , 9501 South King Drive, Chicago, Illinois 60628, United States.,Department of Pharmaceutical Sciences, College of Pharmacy, Marshall B. Ketchum University , 2575 Yorba Linda Boulevard, Fullerton, California 92831, United States
| | - Christian Dupont
- Institut de Recherche en Infectiologie (IRIM), CNRS, UMR 9004, Université de Montpellier , Montpellier Cedex 5 34 293, France
| | - Albertus Viljoen
- Institut de Recherche en Infectiologie (IRIM), CNRS, UMR 9004, Université de Montpellier , Montpellier Cedex 5 34 293, France
| | - Matthias Richard
- Institut de Recherche en Infectiologie (IRIM), CNRS, UMR 9004, Université de Montpellier , Montpellier Cedex 5 34 293, France
| | - Tridib Chaira
- Centre for Drug Design Discovery and Development (C4D), SRM University, Delhi-NCR , Rajiv Gandhi Education City, Sonepat 131 029, Haryana India.,Daiichi Sankyo India Pharma Private Limited , Sector 18, Gurgaon 122 015, Haryana India
| | - Shichun Lun
- JHU Center for TB Research, Johns Hopkins School of Medicine , 1550 Orleans Street, Baltimore, Maryland 21231-1001, United States
| | - William Bishai
- JHU Center for TB Research, Johns Hopkins School of Medicine , 1550 Orleans Street, Baltimore, Maryland 21231-1001, United States
| | - V Samuel Raj
- Centre for Drug Design Discovery and Development (C4D), SRM University, Delhi-NCR , Rajiv Gandhi Education City, Sonepat 131 029, Haryana India
| | - Diane Ordway
- Department of Microbiology, Immunology & Pathology, Mycobacteria Research Laboratory, Colorado State University , Fort Collins, Colorado 80523 United States
| | - Laurent Kremer
- Institut de Recherche en Infectiologie (IRIM), CNRS, UMR 9004, Université de Montpellier , Montpellier Cedex 5 34 293, France.,IRIM, INSERM , 34293 Montpellier, France
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Abstract
Familial hypercholesterolaemia (FH) is a relatively common autosomal dominant genetic condition leading to premature ischaemic vascular disease and mortality if left untreated. Currently, a universal consensus on the diagnostic criteria of FH does not exist but the diagnosis of FH largely relies on the evaluation of low density lipoprotein-cholesterol (LDL-C) levels, a careful documentation of family history, and the identification of clinical features. Diagnosis based purely on lipid levels remains common but there are several limitations to this method of diagnosis both practically and in the proportion of false-negatives and false-positives detected, resulting in substantial under-diagnosis of FH. In some countries, diagnostic algorithms are supplemented with genetic testing of the index case as well as genetic and lipid testing of relatives of the index case. Such "cascade" screening of families following identification of index cases appears to not only improve the rate of diagnosis but is also cost-effective. Currently, we observe a great variation in the excess mortality among patients with FH, which likely reflects a combination of additional genetic and environmental effects on risk overlaid on the risk associated with FH. Current accepted drug therapies for FH include statins and PSCK9 inhibitors. Further work is required to evaluate the cardiovascular disease risk in patients with genetically diagnosed FH and to determine whether a risk-based approach to the treatment of FH is appropriate.
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Affiliation(s)
- D P Hughes
- Department Metabolic Medicine/Chemical Pathology, Lister Hospital, Stevenage, SG1 4AB, UK
| | - A Viljoen
- Department Metabolic Medicine/Chemical Pathology, Lister Hospital, Stevenage, SG1 4AB, UK.
| | - A S Wierzbicki
- Department Metabolic Medicine/Chemical Pathology, Guy's & St Thomas' Hospitals, St Thomas' Hospital, Lambeth Palace Road, London, SE1 7EH, UK
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50
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Viljoen A, Dubois V, Girard-Misguich F, Blaise M, Herrmann JL, Kremer L. The diverse family of MmpL transporters in mycobacteria: from regulation to antimicrobial developments. Mol Microbiol 2017; 104:889-904. [DOI: 10.1111/mmi.13675] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Albertus Viljoen
- Institut de Recherche en Infectiologie de Montpellier (IRIM); CNRS, UMR 9004, Université de Montpellier, France
| | - Violaine Dubois
- INSERM, UMR1173; Université de Versailles Saint-Quentin-en-Yvelines; Montigny-le-Bretonneux 78180 France
| | - Fabienne Girard-Misguich
- INSERM, UMR1173; Université de Versailles Saint-Quentin-en-Yvelines; Montigny-le-Bretonneux 78180 France
| | - Mickaël Blaise
- Institut de Recherche en Infectiologie de Montpellier (IRIM); CNRS, UMR 9004, Université de Montpellier, France
| | - Jean-Louis Herrmann
- INSERM, UMR1173; Université de Versailles Saint-Quentin-en-Yvelines; Montigny-le-Bretonneux 78180 France
| | - Laurent Kremer
- Institut de Recherche en Infectiologie de Montpellier (IRIM); CNRS, UMR 9004, Université de Montpellier, France
- IRIM; INSERM; 34293 Montpellier France
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