1
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Son SY, Bae DW, Kim E, Jeong BG, Kim MY, Youn SY, Yi S, Kim G, Hahn JS, Lee NK, Yoon YJ, Cha SS. Structural investigation of the docking domain assembly from trans-AT polyketide synthases. Structure 2024:S0969-2126(24)00194-1. [PMID: 38908377 DOI: 10.1016/j.str.2024.05.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 05/02/2024] [Accepted: 05/28/2024] [Indexed: 06/24/2024]
Abstract
Docking domains (DDs) located at the C- and N-termini of polypeptides play a crucial role in directing the assembly of polyketide synthases (PKSs), which are multienzyme complexes. Here, we determined the crystal structure of a complex comprising the C-terminal DD (CDDMlnB) and N-terminal DD (NDDMlnC) of macrolactin trans-acyltransferase (AT) PKS that were fused to a functional enzyme, AmpC EC2 β-lactamase. Interface analyses of the CDDMlnB/NDDMlnC complex revealed the molecular intricacies in the core section underpinning the precise DD assembly. Additionally, circular dichroism and steady-state kinetics demonstrated that the formation of the CDDMlnB/NDDMlnC complex had no influence on the structural and functional fidelity of the fusion partner, AmpC EC2. This inspired us to apply the CDDMlnB/NDDMlnC assembly to metabolon engineering. Indeed, DD assembly induced the formation of a complex between 4-coumarate-CoA ligase and chalcone synthase both involved in flavonoid biosynthesis, leading to a remarkable increase in naringenin production in vitro.
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Affiliation(s)
- Se-Young Son
- Department of Chemistry & Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Da-Woon Bae
- Department of Chemistry & Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Eunji Kim
- Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul, Republic of Korea
| | - Bo-Gyeong Jeong
- Department of Chemistry & Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Myeong-Yeon Kim
- Department of Chemistry & Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
| | - So-Yeon Youn
- Department of Chemistry & Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Soojung Yi
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Gyeongmin Kim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
| | - Ji-Sook Hahn
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
| | - Nam Ki Lee
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Yeo Joon Yoon
- Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul, Republic of Korea.
| | - Sun-Shin Cha
- Department of Chemistry & Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea.
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2
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Amormino C, Russo E, Tedeschi V, Fiorillo MT, Paiardini A, Spallotta F, Rosanò L, Tuosto L, Kunkl M. Targeting staphylococcal enterotoxin B binding to CD28 as a new strategy for dampening superantigen-mediated intestinal epithelial barrier dysfunctions. Front Immunol 2024; 15:1365074. [PMID: 38510259 PMCID: PMC10951378 DOI: 10.3389/fimmu.2024.1365074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 02/26/2024] [Indexed: 03/22/2024] Open
Abstract
Staphylococcus aureus is a gram-positive bacterium that may cause intestinal inflammation by secreting enterotoxins, which commonly cause food-poisoning and gastrointestinal injuries. Staphylococcal enterotoxin B (SEB) acts as a superantigen (SAg) by binding in a bivalent manner the T-cell receptor (TCR) and the costimulatory receptor CD28, thus stimulating T cells to produce large amounts of inflammatory cytokines, which may affect intestinal epithelial barrier integrity and functions. However, the role of T cell-mediated SEB inflammatory activity remains unknown. Here we show that inflammatory cytokines produced by T cells following SEB stimulation induce dysfunctions in Caco-2 intestinal epithelial cells by promoting actin cytoskeleton remodelling and epithelial cell-cell junction down-regulation. We also found that SEB-activated inflammatory T cells promote the up-regulation of epithelial-mesenchymal transition transcription factors (EMT-TFs) in a nuclear factor-κB (NF-κB)- and STAT3-dependent manner. Finally, by using a structure-based design approach, we identified a SEB mimetic peptide (pSEB116-132) that, by blocking the binding of SEB to CD28, dampens inflammatory-mediated dysregulation of intestinal epithelial barrier.
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Affiliation(s)
- Carola Amormino
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, Rome, Italy
| | - Emanuela Russo
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, Rome, Italy
| | - Valentina Tedeschi
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, Rome, Italy
| | - Maria Teresa Fiorillo
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, Rome, Italy
| | - Alessandro Paiardini
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, Rome, Italy
| | - Francesco Spallotta
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, Rome, Italy
- Laboratory affiliated to Instituto Pasteur Italia-Fondazione Cenci Bolognetti, Rome, Italy
| | - Laura Rosanò
- Institute of Molecular Biology and Pathology, CNR, Rome, Italy
| | - Loretta Tuosto
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, Rome, Italy
| | - Martina Kunkl
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, Rome, Italy
- Neuroimmunology Unit, IRCCS Santa Lucia Foundation, Rome, Italy
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3
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Rahman S, Saha S, Dasgupta SB, Das AK. Putative staphylococcal enterotoxin possesses two common structural motifs for MHC-II binding. Int J Biol Macromol 2024; 256:128437. [PMID: 38013079 DOI: 10.1016/j.ijbiomac.2023.128437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 11/20/2023] [Accepted: 11/23/2023] [Indexed: 11/29/2023]
Abstract
Staphylococcus aureus has become a significant cause of health risks in humankind. Staphylococcal superantigens (SAgs) or enterotoxins are the key virulent factors that can exhibit acute diseases to severe life-threatening conditions. Recent literature reports S. aureus has steadily gained new enterotoxin genes over the past few decades. In spite of current knowledge of the established SAgs, several questions on putative enterotoxins are still remaining unanswered. Keeping that in mind, this study sheds light on a putative enterotoxin SEl26 to characterize its structural and functional properties. In-silico analyses indicate its close relation with the conventional SAgs, especially the zinc-binding SAgs. Additionally, important residues that are vital for the T-cell receptor (TcR) and major histocompatibility complex class II (MHC-II) interaction were predicted and compared with established SAgs. Besides, our biochemical analyses exhibited the binding of this putative enterotoxin with MHC-II, followed by regulating pro-inflammatory and anti-inflammatory cytokines.
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Affiliation(s)
- Shakilur Rahman
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India.
| | - Saradindu Saha
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India
| | - Somdeb Bose Dasgupta
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India
| | - Amit Kumar Das
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India.
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4
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Huang P, Åbacka H, Varela D, Venskutonytė R, Happonen L, Bogan JS, Gourdon P, Amiry‐Moghaddam MR, André I, Lindkvist‐Petersson K. The intracellular helical bundle of human glucose transporter GLUT4 is important for complex formation with ASPL. FEBS Open Bio 2023; 13:2094-2107. [PMID: 37731227 PMCID: PMC10626271 DOI: 10.1002/2211-5463.13709] [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: 08/18/2023] [Revised: 09/06/2023] [Accepted: 09/19/2023] [Indexed: 09/22/2023] Open
Abstract
Glucose transporters (GLUTs) are responsible for transporting hexose molecules across cellular membranes. In adipocytes, insulin stimulates glucose uptake by redistributing GLUT4 to the plasma membrane. In unstimulated adipose-like mouse cell lines, GLUT4 is known to be retained intracellularly by binding to TUG protein, while upon insulin stimulation, GLUT4 dissociates from TUG. Here, we report that the TUG homolog in human, ASPL, exerts similar properties, i.e., forms a complex with GLUT4. We describe the structural details of complex formation by combining biochemical assays with cross-linking mass spectrometry and computational modeling. Combined, the data suggest that the intracellular domain of GLUT4 binds to the helical lariat of ASPL and contributes to the regulation of GLUT4 trafficking by cooperative binding.
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Affiliation(s)
- Peng Huang
- Department of Experimental Medical ScienceLund UniversitySweden
| | - Hannah Åbacka
- Department of Experimental Medical ScienceLund UniversitySweden
| | - Daniel Varela
- Department of Biochemistry and Structural BiologyLund UniversitySweden
| | - Raminta Venskutonytė
- Department of Experimental Medical ScienceLund UniversitySweden
- LINXS – Lund Institute of Advanced Neutron and X‐ray ScienceSweden
| | - Lotta Happonen
- Division of Infection Medicine, Department of Clinical Sciences LundLund UniversitySweden
| | - Jonathan S. Bogan
- Section of Endocrinology and Metabolism, Department of Internal MedicineYale School of MedicineNew HavenCTUSA
- Department of Cell BiologyYale School of MedicineNew HavenCTUSA
| | - Pontus Gourdon
- Department of Experimental Medical ScienceLund UniversitySweden
| | - Mahmood R. Amiry‐Moghaddam
- Laboratory of Molecular Neuroscience, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical SciencesUniversity of OsloNorway
| | - Ingmar André
- Department of Biochemistry and Structural BiologyLund UniversitySweden
| | - Karin Lindkvist‐Petersson
- Department of Experimental Medical ScienceLund UniversitySweden
- LINXS – Lund Institute of Advanced Neutron and X‐ray ScienceSweden
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5
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Kunkl M, Amormino C, Spallotta F, Caristi S, Fiorillo MT, Paiardini A, Kaempfer R, Tuosto L. Bivalent binding of staphylococcal superantigens to the TCR and CD28 triggers inflammatory signals independently of antigen presenting cells. Front Immunol 2023; 14:1170821. [PMID: 37207220 PMCID: PMC10189049 DOI: 10.3389/fimmu.2023.1170821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/21/2023] [Indexed: 05/21/2023] Open
Abstract
Staphylococcus aureus superantigens (SAgs) such as staphylococcal enterotoxin A (SEA) and B (SEB) are potent toxins stimulating T cells to produce high levels of inflammatory cytokines, thus causing toxic shock and sepsis. Here we used a recently released artificial intelligence-based algorithm to better elucidate the interaction between staphylococcal SAgs and their ligands on T cells, the TCR and CD28. The obtained computational models together with functional data show that SEB and SEA are able to bind to the TCR and CD28 stimulating T cells to activate inflammatory signals independently of MHC class II- and B7-expressing antigen presenting cells. These data reveal a novel mode of action of staphylococcal SAgs. By binding to the TCR and CD28 in a bivalent way, staphylococcal SAgs trigger both the early and late signalling events, which lead to massive inflammatory cytokine secretion.
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Affiliation(s)
- Martina Kunkl
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University, Rome, Italy
| | - Carola Amormino
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University, Rome, Italy
| | - Francesco Spallotta
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University, Rome, Italy
- Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University, Rome, Italy
| | - Silvana Caristi
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University, Rome, Italy
| | - Maria Teresa Fiorillo
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University, Rome, Italy
| | - Alessandro Paiardini
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, Rome, Italy
| | - Raymond Kaempfer
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Loretta Tuosto
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University, Rome, Italy
- Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University, Rome, Italy
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6
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Uzunҫayır S, Vera‐Rodriguez A, Regenthal P, Åbacka H, Emanuelsson C, Bahl CD, Lindkvist‐Petersson K. Analyses of the complex formation of staphylococcal enterotoxin A and the human gp130 cytokine receptor. FEBS Lett 2022; 596:910-923. [DOI: 10.1002/1873-3468.14292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/14/2021] [Accepted: 01/10/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Sibel Uzunҫayır
- Department of Experimental Medical Science Lund University BMC C13 22 184 Lund Sweden
| | - Arturo Vera‐Rodriguez
- Institute for Protein Innovation Boston USA
- Division of Hematology‐Oncology, Boston Children’s Hospital Harvard Medical School Boston USA
| | - Paulina Regenthal
- Department of Experimental Medical Science Lund University BMC C13 22 184 Lund Sweden
| | - Hannah Åbacka
- Department of Experimental Medical Science Lund University BMC C13 22 184 Lund Sweden
| | - Cecilia Emanuelsson
- Department of Chemistry Division for Biochemistry and Structural Biology Lund University Lund Sweden
| | - Christopher D. Bahl
- Institute for Protein Innovation Boston USA
- Division of Hematology‐Oncology, Boston Children’s Hospital Harvard Medical School Boston USA
| | - Karin Lindkvist‐Petersson
- Department of Experimental Medical Science Lund University BMC C13 22 184 Lund Sweden
- LINXS ‐ Lund Institute of Advanced Neutron and X‐ray Science Scheelevägen 19 SE‐223 70 Lund Sweden
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7
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Kunkl M, Amormino C, Caristi S, Tedeschi V, Fiorillo MT, Levy R, Popugailo A, Kaempfer R, Tuosto L. Binding of Staphylococcal Enterotoxin B (SEB) to B7 Receptors Triggers TCR- and CD28-Mediated Inflammatory Signals in the Absence of MHC Class II Molecules. Front Immunol 2021; 12:723689. [PMID: 34489975 PMCID: PMC8418141 DOI: 10.3389/fimmu.2021.723689] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/02/2021] [Indexed: 01/19/2023] Open
Abstract
The inflammatory activity of staphylococcal enterotoxin B (SEB) relies on its capacity to trigger polyclonal T-cell activation by binding both T-cell receptor (TCR) and costimulatory receptor CD28 on T cells and MHC class II and B7 molecules on antigen presenting cells (APC). Previous studies highlighted that SEB may bind TCR and CD28 molecules independently of MHC class II, yet the relative contribution of these interactions to the pro-inflammatory function of SEB remained unclear. Here, we show that binding to MHC class II is dispensable for the inflammatory activity of SEB, whereas binding to TCR, CD28 and B7 molecules is pivotal, in both human primary T cells and Jurkat T cell lines. In particular, our finding is that binding of SEB to B7 molecules suffices to trigger both TCR- and CD28-mediated inflammatory signalling. We also provide evidence that, by strengthening the interaction between CD28 and B7, SEB favours the recruitment of the TCR into the immunological synapse, thus inducing lethal inflammatory signalling.
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Affiliation(s)
- Martina Kunkl
- Department of Biology and Biotechnology Charles Darwin, Sapienza University, Rome, Italy.,Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University, Rome, Italy
| | - Carola Amormino
- Department of Biology and Biotechnology Charles Darwin, Sapienza University, Rome, Italy.,Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University, Rome, Italy
| | - Silvana Caristi
- Department of Biology and Biotechnology Charles Darwin, Sapienza University, Rome, Italy.,Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University, Rome, Italy
| | - Valentina Tedeschi
- Department of Biology and Biotechnology Charles Darwin, Sapienza University, Rome, Italy
| | - Maria Teresa Fiorillo
- Department of Biology and Biotechnology Charles Darwin, Sapienza University, Rome, Italy
| | - Revital Levy
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Andrey Popugailo
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Raymond Kaempfer
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Loretta Tuosto
- Department of Biology and Biotechnology Charles Darwin, Sapienza University, Rome, Italy.,Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University, Rome, Italy
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8
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Abstract
Nonclonal innate immune responses mediated by germ line-encoded receptors, such as Toll-like receptors or natural killer receptors, are commonly contrasted with diverse, clonotypic adaptive responses of lymphocyte antigen receptors generated by somatic recombination. However, the Variable (V) regions of antigen receptors include germ line-encoded motifs unaltered by somatic recombination, and theoretically available to mediate nonclonal, innate responses, that are independent of or largely override clonotypic responses. Recent evidence demonstrates that such responses exist, underpinning the associations of particular γδ T cell receptors (TCRs) with specific anatomical sites. Thus, TCRγδ can make innate and adaptive responses with distinct functional outcomes. Given that αβ T cells and B cells can also make nonclonal responses, we consider that innate responses of antigen receptor V-regions may be more widespread, for example, inducing states of preparedness from which adaptive clones are better selected. We likewise consider that potent, nonclonal T cell responses to microbial superantigens may reflect subversion of physiologic innate responses of TCRα/β chains.
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Affiliation(s)
- Adrian C Hayday
- Peter Gorer Department of Immunobiology, King's College, London, SE1 9RT, United Kingdom; .,Immunosurveillance Laboratory, Francis Crick Institute, London, NW1 1AT, United Kingdom
| | - Pierre Vantourout
- Peter Gorer Department of Immunobiology, King's College, London, SE1 9RT, United Kingdom; .,Immunosurveillance Laboratory, Francis Crick Institute, London, NW1 1AT, United Kingdom
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9
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Liu Y, Song Z, Ge S, Zhang J, Xu L, Yang F, Lu D, Luo P, Gu J, Zou Q, Zeng H. Determining the immunological characteristics of a novel human monoclonal antibody developed against staphylococcal enterotoxin B. Hum Vaccin Immunother 2020; 16:1708-1718. [PMID: 32275466 DOI: 10.1080/21645515.2020.1744362] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Staphylococci are the main cause of nosocomial infections globally. The exotoxin staphylococcal enterotoxin B (SEB) produced by methicillin-resistant Staphylococcus aureus is a major cause of pathology after a staphylococcal infection. We previously isolated an anti-SEB human monoclonal antibody designated as M0313. Here we further characterize this antibody in vitro and in vivo. Immunoblotting analysis and ELISA results indicated that M0313 accurately recognized and bound to SEB. Its binding affinity to native SEB was measured at the low nM level. M0313 effectively inhibited SEB from inducing mouse splenic lymphocyte and human peripheral blood mononuclear cell proliferation and cytokine release in cell culture. M0313 also neutralized SEB toxicity in BALB/c female mice. Most importantly, M0313 promoted the survival of mice treated with SEB-expressing bacteria. In-vivo imaging revealed that M0313 treatment significantly reduced the replication of SEB-expressing bacteria in mice. The neutralization capacity of M0313 correlated with its ability to block SEB from binding to major histocompatibility complex II and T-cell receptor by binding to the SEB residues 85-102 and 90-92. Thus, the monoclonal antibody M0313 may be developed into a therapeutic agent.
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Affiliation(s)
- Yuanyuan Liu
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Laboratory Medicine, Third Military Medical University , Chongqing, PR China
| | - Zhen Song
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Laboratory Medicine, Third Military Medical University , Chongqing, PR China.,Clinical Laboratory Department, Army 954th Hospital, General Hospital of Tibet Military Region , Tibet, PR China
| | - Shuang Ge
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Laboratory Medicine, Third Military Medical University , Chongqing, PR China
| | - Jinyong Zhang
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Laboratory Medicine, Third Military Medical University , Chongqing, PR China
| | - Limin Xu
- Research and Development Department, Chengdu Olymvax Biotechnology Co., Ltd ., Chengdu, Sichuan, PR China
| | - Feng Yang
- Research and Development Department, Chengdu Olymvax Biotechnology Co., Ltd ., Chengdu, Sichuan, PR China
| | - Dongshui Lu
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Laboratory Medicine, Third Military Medical University , Chongqing, PR China
| | - Ping Luo
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Laboratory Medicine, Third Military Medical University , Chongqing, PR China
| | - Jiang Gu
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Laboratory Medicine, Third Military Medical University , Chongqing, PR China
| | - Quanming Zou
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Laboratory Medicine, Third Military Medical University , Chongqing, PR China
| | - Hao Zeng
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Laboratory Medicine, Third Military Medical University , Chongqing, PR China
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10
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Zeng C, Liu Z, Han Z. Structure of Staphylococcal Enterotoxin N: Implications for Binding Properties to Its Cellular Proteins. Int J Mol Sci 2019; 20:ijms20235921. [PMID: 31775346 PMCID: PMC6928602 DOI: 10.3390/ijms20235921] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 11/20/2019] [Accepted: 11/22/2019] [Indexed: 01/26/2023] Open
Abstract
Staphylococcus aureus strains produce a unique family of immunostimulatory exotoxins termed as bacterial superantigens (SAgs), which cross-link major histocompatibility complex class II (MHC II) molecule and T-cell receptor (TCR) to stimulate large numbers of T cells at extremely low concentrations. SAgs are associated with food poisoning and toxic shock syndrome. To date, 26 genetically distinct staphylococcal SAgs have been reported. This study reports the first X-ray structure of newly characterized staphylococcal enterotoxin N (SEN). SEN possesses the classical two domain architecture that includes an N-terminal oligonucleotide-binding fold and a C-terminal β-grasp domain. Amino acid and structure alignments revealed that several critical amino acids that are proposed to be responsible for MHC II and TCR molecule engagements are variable in SEN, suggesting that SEN may adopt a different binding mode to its cellular receptors. This work helps better understand the mechanisms of action of SAgs.
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Affiliation(s)
- Chi Zeng
- College of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan 430023, China; (C.Z.); (Z.L.)
- Hubei Province Fresh Food Engineering Research Center, Wuhan Polytechnic University, Wuhan 430023, China
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis (Ministry of Agriculture), Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Zhaoxin Liu
- College of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan 430023, China; (C.Z.); (Z.L.)
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zhenggang Han
- College of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan 430023, China; (C.Z.); (Z.L.)
- Correspondence:
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11
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Popugailo A, Rotfogel Z, Supper E, Hillman D, Kaempfer R. Staphylococcal and Streptococcal Superantigens Trigger B7/CD28 Costimulatory Receptor Engagement to Hyperinduce Inflammatory Cytokines. Front Immunol 2019; 10:942. [PMID: 31114583 PMCID: PMC6503043 DOI: 10.3389/fimmu.2019.00942] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 04/12/2019] [Indexed: 11/13/2022] Open
Abstract
Staphylococcal and streptococcal superantigens are virulence factors that cause toxic shock by hyperinducing inflammatory cytokines. Effective T-cell activation requires interaction between the principal costimulatory receptor CD28 and its two coligands, B7-1 (CD80) and B7-2 (CD86). To elicit an inflammatory cytokine storm, bacterial superantigens must bind directly into the homodimer interfaces of CD28 and B7-2. Recent evidence revealed that by engaging CD28 and B7-2 directly at their dimer interface, staphylococcal enterotoxin B (SEB) potently enhances intercellular synapse formation mediated by B7-2 and CD28, resulting in T-cell hyperactivation. Here, we addressed the question, whether diverse bacterial superantigens share the property of triggering B7-2/CD28 receptor engagement and if so, whether they are capable of enhancing also the interaction between B7-1 and CD28, which occurs with an order-of-magnitude higher affinity. To this end, we compared the ability of distinct staphylococcal and streptococcal superantigens to enhance intercellular B7-2/CD28 engagement. Each of these diverse superantigens promoted B7-2/CD28 engagement to a comparable extent. Moreover, they were capable of triggering the intercellular B7-1/CD28 interaction, analyzed by flow cytometry of co-cultured cell populations transfected separately to express human CD28 or B7-1. Streptococcal mitogenic exotoxin Z (SMEZ), the most potent superantigen known, was as sensitive as SEB, SEA and toxic shock syndrome toxin-1 (TSST-1) to inhibition of inflammatory cytokine induction by CD28 and B7-2 dimer interface mimetic peptides. Thus, superantigens act not only by mediating unconventional interaction between MHC-II molecule and T-cell receptor but especially, by strongly promoting engagement of CD28 by its B7-2 and B7-1 coligands, a critical immune checkpoint, forcing the principal costimulatory axis to signal excessively. Our results show that the diverse superantigens use a common mechanism to subvert the inflammatory response, strongly enhancing B7-1/CD28 and B7-2/CD28 costimulatory receptor engagement.
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Affiliation(s)
- Andrey Popugailo
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Ziv Rotfogel
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Emmanuelle Supper
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Dalia Hillman
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Raymond Kaempfer
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
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Binding of Catechins to Staphylococcal Enterotoxin A. Molecules 2018; 23:molecules23051125. [PMID: 29747413 PMCID: PMC6099397 DOI: 10.3390/molecules23051125] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/06/2018] [Accepted: 05/07/2018] [Indexed: 12/12/2022] Open
Abstract
Staphylococcal enterotoxin A (SEA) is a toxin protein, and is the most common cause of staphylococcal food poisoning. Polyphenols, such as catechins, are known to interact with proteins. In this study, we investigated the binding of catechins to SEA using SPR (Biacore), Fourier transform infrared spectroscopy (FT-IR), isothermal titration calorimetry (ITC), and protein-ligand docking. We found that (−)-epigallocatechin gallate (EGCG) could strongly bind to SEA. According to thermodynamic parameters, a negative ΔG indicated that the interaction between EGCG and SEA was spontaneous, and the electrostatic force accompanied by hydrophobic binding forces may play a major role in the binding. Data from Western blot analysis and docking simulation suggest that the hydroxyl group at position 3 of the galloyl group in the catechin structure was responsible for binding affinity with the Y91 of the A-6 region of SEA active sites. Our results provide further understanding of the binding interactions between catechins and SEA, and the inhibition of toxin activities by catechins.
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