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Bonnecaze L, Jumel K, Vial A, Khemtemourian L, Feuillie C, Molinari M, Lecomte S, Mathelié-Guinlet M. N-Formylation modifies membrane damage associated with PSMα3 interfacial fibrillation. NANOSCALE HORIZONS 2024; 9:1175-1189. [PMID: 38689531 DOI: 10.1039/d4nh00088a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
The virulence of Staphylococcus aureus, a multi-drug resistant pathogen, notably depends on the expression of the phenol soluble modulins α3 (PSMα3) peptides, able to self-assemble into amyloid-like cross-α fibrils. Despite remarkable advances evidencing the crucial, yet insufficient, role of fibrils in PSMα3 cytotoxic activities towards host cells, the relationship between its molecular structures, assembly propensities, and modes of action remains an open intriguing problem. In this study, combining atomic force microscopy (AFM) imaging and infrared spectroscopy, we first demonstrated in vitro that the charge provided by the N-terminal capping of PSMα3 alters its interactions with model membranes of controlled lipid composition without compromising its fibrillation kinetics or morphology. N-formylation eventually dictates PSMα3-membrane binding via electrostatic interactions with the lipid head groups. Furthermore, PSMα3 insertion within the lipid bilayer is favoured by hydrophobic interactions with the lipid acyl chains only in the fluid phase of membranes and not in the gel-like ordered domains. Strikingly, our real-time AFM imaging emphasizes how intermediate protofibrillar entities, formed along PSMα3 self-assembly and promoted at the membrane interface, likely disrupt membrane integrity via peptide accumulation and subsequent membrane thinning in a peptide concentration and lipid-dependent manner. Overall, our multiscale and multimodal approach sheds new light on the key roles of N-formylation and intermediate self-assembling entities, rather than mature fibrils, in dictating deleterious interactions of PSMα3 with membrane lipids, likely underscoring its ultimate cellular toxicity in vivo, and in turn S. aureus pathogenesis.
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Affiliation(s)
- Laura Bonnecaze
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, F-33600 Pessac, France.
| | - Katlyn Jumel
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, F-33600 Pessac, France.
| | - Anthony Vial
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, F-33600 Pessac, France.
| | | | - Cécile Feuillie
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, F-33600 Pessac, France.
| | - Michael Molinari
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, F-33600 Pessac, France.
| | - Sophie Lecomte
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, F-33600 Pessac, France.
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Zhu R, Stone T, Wang Y. The role of shear rates on amyloid formation from biofilm peptide phenol-soluble modulins. Biophys J 2024; 123:1106-1115. [PMID: 38549371 PMCID: PMC11079943 DOI: 10.1016/j.bpj.2024.03.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 01/28/2024] [Accepted: 03/26/2024] [Indexed: 04/15/2024] Open
Abstract
Biofilms, microbial communities enclosed in the self-produced extracellular matrix, have a significant impact on human health, environment, and industry. The pathogen Staphylococcus aureus (S. aureus) is recognized as one of the most frequent causes of biofilm-related infections. Phenol-soluble modulins (PSMs) serve as a crucial component, fortifying S. aureus biofilm matrix through self-assembly into amyloid fibrils, which enhances S. aureus colonization and resistance to antibiotics. However, the role of shear rate, one of the critical physiological factors within blood vessels, on the formation of PSM amyloids remains poorly understood. In this work, using a combination of thioflavin T fluorescence kinetic studies, circular dichroism spectrometry, and electron microscopy, we demonstrated that shear rates ranging from 150 to 300 s-1 accelerate fibrillation of PSMα1, α3, and α4 into amyloids, resulting in elongated amyloid structures. Furthermore, PSMα1, α3, and α4 predominantly self-assembled into amyloid fibers with a cross-α structure under shear conditions, deviating from the typical β-sheet configuration of PSM amyloids. These findings imply the role of shear rates within the bloodstream on enhancing PSM self-assembly that is associated with S. aureus biofilm formation.
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Affiliation(s)
- Runyao Zhu
- Department of Chemical & Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Trevor Stone
- Department of Chemical & Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana; Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia
| | - Yichun Wang
- Department of Chemical & Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana.
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Wang X, Uppu DSSM, Dickey SW, Burgin DJ, Otto M, Lee JC. Staphylococcus aureus delta toxin modulates both extracellular membrane vesicle biogenesis and amyloid formation. mBio 2023; 14:e0174823. [PMID: 37795985 PMCID: PMC10653798 DOI: 10.1128/mbio.01748-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 08/15/2023] [Indexed: 10/06/2023] Open
Abstract
IMPORTANCE Extracellular membrane vesicles (MVs) produced by Staphylococcus aureus in planktonic cultures encapsulate a diverse cargo of bacterial proteins, nucleic acids, and glycopolymers that are protected from destruction by external factors. δ-toxin, a member of the phenol soluble modulin family, was shown to be critical for MV biogenesis. Amyloid fibrils co-purified with MVs generated by virulent, community-acquired S. aureus strains, and fibril formation was dependent on expression of the S. aureus δ-toxin gene (hld). Mass spectrometry data confirmed that the amyloid fibrils were comprised of δ-toxin. Although S. aureus MVs were produced in vivo in a localized murine infection model, amyloid fibrils were not observed in the in vivo setting. Our findings provide critical insights into staphylococcal factors involved in MV biogenesis and amyloid formation.
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Affiliation(s)
- Xiaogang Wang
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Divakara SSM Uppu
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Seth W. Dickey
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
- Department of Veterinary Medicine, Virginia-Maryland Regional College of Veterinary Medicine,University of Maryland, Bethesda, Maryland, USA
| | - Dylan J. Burgin
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Jean C. Lee
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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Tammara V, Das A. The Molecular Mechanism of PSMα3 Aggregation: A New View. J Phys Chem B 2023; 127:8317-8330. [PMID: 37734054 DOI: 10.1021/acs.jpcb.3c03806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/23/2023]
Abstract
The emergence of a novel cross-α fibrillar structure, unlike the commonly observed sequence-independent cross-β one, of a 22-residue bacterial virulent amphipathic α-helical peptide of the phenol soluble modulin (PSM) family, PSMα3, with many deleterious effects on human life, has infused uncertainty to the paradigm of the intrinsically polymorphic, multivariate, multiphasic, and cross-sequence-cross-disease entangled protein aggregation landscape and hence on the identity of the therapeutic target. We, here, deconvolute the factors contributing to the genesis and hence the transition of lower to higher order aggregates of PSMα3 in its natural state and three noncanonical designed variants using conventional and enhanced sampling approach-based atomistic simulations. PSMα3 shows structural polymorphism with nominal α-helicity, substantial β-propensity, and dominant random-coil features, irrespective of the extent of aggregation. Moreover, the individual features of the overall amphipathicity operate alternatively depending on the extent and organization of aggregation; the dominance gradually moves from charged to hydrophobic residues with the progressive generation of higher order aggregates (dimer to oligomer to fibril) and with increasing orderedness of the self-assembled construct (oligomer vs dimer/fibril). Similarly, the contribution of interchain salt bridges decreases with increasing order of aggregation (dimer to oligomer to fibril). However, the intrachain salt bridges consistently display their role in all phases of aggregation. Such phase-independent features also include equivalent roles of electrostatic and van der Waals forces on intrachain interactions, sole contribution of van der Waals forces on interchain cross-talk, and negligible peptide-water relationship. Finally, we propose a conjugate peptide-based aggregation suppressor having a single-point proline mutation.
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Affiliation(s)
- Vaishnavi Tammara
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, Maharashtra 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Atanu Das
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, Maharashtra 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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Wang X, Uppu DS, Dickey SW, Burgin DJ, Otto M, Lee JC. Staphylococcus aureus Delta Toxin Modulates both Extracellular Membrane Vesicle Biogenesis and Amyloid Formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.23.533957. [PMID: 36993475 PMCID: PMC10055364 DOI: 10.1101/2023.03.23.533957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Staphylococcus aureus secretes phenol-soluble modulins (PSMs), a family of small, amphipathic, secreted peptides with multiple biologic activities. Community-acquired S. aureus strains produce high levels of PSMs in planktonic cultures, and PSM alpha peptides have been shown to augment the release of extracellular membrane vesicles (MVs). We observed that amyloids, aggregates of proteins characterized by a fibrillar morphology and stained with specific dyes, co-purified with MVs harvested from cell-free culture supernatants of community-acquired S. aureus strains. δ-toxin was a major component of amyloid fibrils that co-purified with strain LAC MVs, and δ-toxin promoted the production of MVs and amyloid fibrils in a dose-dependent manner. To determine whether MVs and amyloid fibrils were generated under in vivo conditions, we inoculated mice with S. aureus harvested from planktonic cultures. Bacterial MVs could be isolated and purified from lavage fluids recovered from infected animals. Although δ-toxin was the most abundant PSM in lavage fluids, amyloid fibrils could not be detected in these samples. Our findings expand our understanding of amyloid fibril formation in S. aureus cultures, reveal important roles of δ-toxin in amyloid fibril formation and MV biogenesis, and demonstrate that MVs are generated in vivo in a staphylococcal infection model. Importance Extracellular membrane vesicles (MVs) produced by Staphylococcus aureus in planktonic cultures encapsulate a diverse cargo of bacterial proteins, nucleic acids, and glycopolymers that are protected from destruction by external factors. δ-toxin, a member of the phenol soluble modulin family, was shown to be critical for MV biogenesis. Amyloid fibrils co-purified with MVs generated by virulent, community-acquired S. aureus strains, and fibril formation was dependent on expression of the S. aureus δ-toxin gene ( hld ). Mass spectrometry data confirmed that the amyloid fibrils were comprised of δ-toxin. Although S. aureus MVs were produced in vivo in a localized murine infection model, amyloid fibrils were not observed in the in vivo setting. Our findings provide critical insights into staphylococcal factors involved in MV biogenesis and amyloid formation.
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Yufang L, Shijun L, Kun Y, Rongxiang G, Xin Z, Yanan S, Aixiang H. Antibiofilm mechanism of a novel milk-derived antimicrobial peptide against Staphylococcus aureus by down regulating agr quorum sensing system. J Appl Microbiol 2022; 133:2198-2209. [PMID: 35661493 DOI: 10.1111/jam.15653] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/12/2022] [Accepted: 05/30/2022] [Indexed: 11/29/2022]
Abstract
AIMS Staphylococcus aureus has emerged as a serious threat to food safety owing to biofilm formation. The study aimed to examine antibiofilm mechanism of a novel milk-derived antimicrobial peptide BCp12 against it. METHODS AND RESULTS Anti-biofilm activity of BCp12 was studied by crystal violet staining, MTT assay, motility, SEM and CLSM. TMT proteome, real-time PCR, and molecular docking in silico were conducted to evaluate the mechanism of BCp12 against S. aureus biofilm. The results showed that BCp12 had significant anti-biofilm activity at 1×MIC and sub-MIC. BCp12 induced the dispersion of structure of S. aureus biofilm BCp12 inhibited the movement of S. aureus. A total of 703 proteins were down-regulated and 334 proteins were up-regulated after BCp12 treatment. The proteins (agrA, agrB, agrC, and psmβ) of the QS systems were down-regulated. Additionally, the expression of the agr-related genes, agrA, agrB, agrC, and psmβ were down-regulated. BCp12 was bound to the receptor proteins agrA and agrC through hydrogen bonds and π-π bonds. CONCLUSIONS The results indicated the antibiofilm activity of BCp12 and it inhibiting biofilm formation by interfering agr QS system. SIGNIFICANCE AND IMPACT OF STUDY BCp12 has the potential to be a novel anti-biofilm agent against S. aureus biofilm and used in the food industry.
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Affiliation(s)
- Li Yufang
- College of Food Science and Technology, Yunnan Agricultural University, Yunnan 650201, P. R. China
| | - Li Shijun
- College of Food Science and Technology, Yunnan Agricultural University, Yunnan 650201, P. R. China
| | - Yang Kun
- College of Food Science and Technology, Yunnan Agricultural University, Yunnan 650201, P. R. China
| | - Guo Rongxiang
- College of Food Science and Technology, Yunnan Agricultural University, Yunnan 650201, P. R. China
| | - Zhu Xin
- College of Food Science and Technology, Yunnan Agricultural University, Yunnan 650201, P. R. China
| | - Shi Yanan
- College of Food Science and Technology, Yunnan Agricultural University, Yunnan 650201, P. R. China
| | - Huang Aixiang
- College of Food Science and Technology, Yunnan Agricultural University, Yunnan 650201, P. R. China
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Interaction of membrane vesicles with the Pseudomonas functional amyloid protein FapC facilitates amyloid formation. BBA ADVANCES 2022; 2:100055. [PMID: 37082589 PMCID: PMC10074931 DOI: 10.1016/j.bbadva.2022.100055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/13/2022] [Accepted: 09/16/2022] [Indexed: 11/20/2022] Open
Abstract
Functional amyloids (FA) are proteins which are evolutionarily optimized to form highly stable fibrillar structures that strengthen the bacterial biofilm matrix. FA such as CsgA (E. coli) and FapC (Pseudomonas) are secreted to the bacterial surface where they integrate into growing fibril structures projecting from the outer membrane. FA are exposed to membrane surfaces in this process, but it remains unclear how membranes can interact with FA and potentially affect the self-assembly. Here we report the effect of different vesicles (DOPG, DMPG, DOPS, DOPC and DMPC) on the kinetics and structural endpoints of FapC fibrillation using various biophysical techniques. Particularly anionic lipids such as DMPG trigger FapC fibrillation, and the protein's second repeat sequence (R2) appears to be important for this interaction. Vesicles formed from phospholipids extracted from three different Pseudomonas strains (Δfap, ΔFapC and pfap) induce FapC fibrillation by accelerating nucleation. The general aggregation inhibitor epigallocatechin gallate (EGCG) inhibits FapC fibrillation by blocking interactions between FapC and vesicles and redirecting FapC monomers to oligomer structures. Our work indicates that biological membranes can contribute significantly to the fibrillation of functional amyloid.
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