1
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Woelfel S, Silva MS, Stecher B. Intestinal colonization resistance in the context of environmental, host, and microbial determinants. Cell Host Microbe 2024; 32:820-836. [PMID: 38870899 DOI: 10.1016/j.chom.2024.05.002] [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: 02/15/2024] [Revised: 05/07/2024] [Accepted: 05/07/2024] [Indexed: 06/15/2024]
Abstract
Microbial communities that colonize the human gastrointestinal (GI) tract defend against pathogens through a mechanism known as colonization resistance (CR). Advances in technologies such as next-generation sequencing, gnotobiotic mouse models, and bacterial cultivation have enhanced our understanding of the underlying mechanisms and the intricate microbial interactions involved in CR. Rather than being attributed to specific microbial clades, CR is now understood to arise from a dynamic interplay between microbes and the host and is shaped by metabolic, immune, and environmental factors. This evolving perspective underscores the significance of contextual factors, encompassing microbiome composition and host conditions, in determining CR. This review highlights recent research that has shifted its focus toward elucidating how these factors interact to either promote or impede enteric infections. It further discusses future research directions to unravel the complex relationship between host, microbiota, and environmental determinants in safeguarding against GI infections to promote human health.
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Affiliation(s)
- Simon Woelfel
- Max von Pettenkofer-Institute for Hygiene and Clinical Microbiology, Ludwig Maximilian University of Munich, 80336 Munich, Germany
| | - Marta Salvado Silva
- Max von Pettenkofer-Institute for Hygiene and Clinical Microbiology, Ludwig Maximilian University of Munich, 80336 Munich, Germany
| | - Bärbel Stecher
- Max von Pettenkofer-Institute for Hygiene and Clinical Microbiology, Ludwig Maximilian University of Munich, 80336 Munich, Germany; German Center for Infection Research (DZIF), partner site LMU Munich, Munich, Germany.
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2
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Ahmed WS, Geethakumari AM, Sultana A, Fatima A, Philip AM, Uddin SMN, Biswas KH. A slow but steady nanoLuc: R162A mutation results in a decreased, but stable, nanoLuc activity. Int J Biol Macromol 2024; 269:131864. [PMID: 38692549 DOI: 10.1016/j.ijbiomac.2024.131864] [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: 11/04/2023] [Revised: 04/21/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024]
Abstract
NanoLuc (NLuc) luciferase has found extensive application in designing a range of biological assays, including gene expression analysis, protein-protein interaction, and protein conformational changes due to its enhanced brightness and small size. However, questions related to its mechanism of interaction with the substrate, furimazine, as well as bioluminescence activity remain elusive. Here, we combined molecular dynamics (MD) simulation and mutational analysis to show that the R162A mutation results in a decreased but stable bioluminescence activity of NLuc in living cells and in vitro. Specifically, we performed multiple, all-atom, explicit solvent MD simulations of the apo and furimazine-docked (holo) NLuc structures revealing differential dynamics of the protein in the absence and presence of the ligand. Further, analysis of trajectories for hydrogen bonds (H-bonds) formed between NLuc and furimazine revealed substantial H-bond interaction between R162 and Q32 residues. Mutation of the two residues in NLuc revealed a decreased but stable activity of the R162A, but not Q32A, mutant NLuc in live cell and in vitro assays performed using lysates prepared from cells expressing the proteins and with the furimazine substrate. In addition to highlighting the role of the R162 residue in NLuc activity, we believe that the mutant NLuc will find wide application in designing in vitro assays requiring extended monitoring of NLuc bioluminescence activity. SIGNIFICANCE: Bioluminescence has been extensively utilized in developing a variety of biological and biomedical assays. In this regard, engineering of brighter bioluminescent proteins, i.e. luciferases, has played a significant role. This is acutely exemplified by the engineering of the NLuc luciferase, which is small in size and displays much enhanced bioluminescence and thermal stability compared to previously available luciferases. While enhanced bioluminescent activity is desirable in a multitude of biological and biomedical assays, it would also be useful to develop variants of the protein that display a prolonged bioluminescence activity. This is specifically relevant in designing assays that require bioluminescence for extended periods, such as in the case of biosensors designed for monitoring slow enzymatic or cellular signaling reactions, without necessitating multiple rounds of luciferase substrate addition or any specialized reagents that result in increased assay costs. In the current manuscript, we report a mutant NLuc that possesses a stable and prolonged bioluminescence activity, albeit lower than the wild-type NLuc, and envisage a wider application of the mutant NLuc in designing biosensors for monitoring slower biological and biomedical events.
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Affiliation(s)
- Wesam S Ahmed
- Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, Doha 34110, Qatar
| | - Anupriya M Geethakumari
- Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, Doha 34110, Qatar
| | - Asfia Sultana
- Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, Doha 34110, Qatar
| | - Asma Fatima
- Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, Doha 34110, Qatar
| | - Angelin M Philip
- Division of Genomics and Translational Biomedicine, College of Health and Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, Doha 34110, Qatar
| | - S M Nasir Uddin
- Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, Doha 34110, Qatar
| | - Kabir H Biswas
- Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, Doha 34110, Qatar.
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3
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Fromm K, Ortelli M, Boegli A, Dehio C. Translocation of YopJ family effector proteins through the VirB/VirD4 T4SS of Bartonella. Proc Natl Acad Sci U S A 2024; 121:e2310348121. [PMID: 38709922 PMCID: PMC11098119 DOI: 10.1073/pnas.2310348121] [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: 07/18/2023] [Accepted: 03/25/2024] [Indexed: 05/08/2024] Open
Abstract
The evolutionary conserved YopJ family comprises numerous type-III-secretion system (T3SS) effectors of diverse mammalian and plant pathogens that acetylate host proteins to dampen immune responses. Acetylation is mediated by a central acetyltransferase domain that is flanked by conserved regulatory sequences, while a nonconserved N-terminal extension encodes the T3SS-specific translocation signal. Bartonella spp. are facultative-intracellular pathogens causing intraerythrocytic bacteremia in their mammalian reservoirs and diverse disease manifestations in incidentally infected humans. Bartonellae do not encode a T3SS, but most species possess a type-IV-secretion system (T4SS) to translocate Bartonella effector proteins (Beps) into host cells. Here we report that the YopJ homologs present in Bartonellae species represent genuine T4SS effectors. Like YopJ family T3SS effectors of mammalian pathogens, the "Bartonella YopJ-like effector A" (ByeA) of Bartonella taylorii also targets MAP kinase signaling to dampen proinflammatory responses, however, translocation depends on a functional T4SS. A split NanoLuc luciferase-based translocation assay identified sequences required for T4SS-dependent translocation in conserved regulatory regions at the C-terminus and proximal to the N-terminus of ByeA. The T3SS effectors YopP from Yersinia enterocolitica and AvrA from Salmonella Typhimurium were also translocated via the Bartonella T4SS, while ByeA was not translocated via the Yersinia T3SS. Our data suggest that YopJ family T3SS effectors may have evolved from an ancestral T4SS effector, such as ByeA of Bartonella. In this evolutionary scenario, the signal for T4SS-dependent translocation encoded by N- and C-terminal sequences remained functional in the derived T3SS effectors due to the essential role these sequences coincidentally play in regulating acetyltransferase activity.
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Affiliation(s)
- Katja Fromm
- Biozentrum, University of Basel, Basel4056, Switzerland
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4
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Shizukuishi S, Ogawa M, Kuroda E, Hamaguchi S, Sakuma C, Kakuta S, Tanida I, Uchiyama Y, Akeda Y, Ryo A, Ohnishi M. Pneumococcal sialidase promotes bacterial survival by fine-tuning of pneumolysin-mediated membrane disruption. Cell Rep 2024; 43:113962. [PMID: 38483905 DOI: 10.1016/j.celrep.2024.113962] [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: 10/02/2023] [Revised: 01/24/2024] [Accepted: 02/28/2024] [Indexed: 04/02/2024] Open
Abstract
Pneumolysin (Ply) is an indispensable cholesterol-dependent cytolysin for pneumococcal infection. Although Ply-induced disruption of pneumococci-containing endosomal vesicles is a prerequisite for the evasion of endolysosomal bacterial clearance, its potent activity can be a double-edged sword, having a detrimental effect on bacterial survivability by inducing severe endosomal disruption, bactericidal autophagy, and scaffold epithelial cell death. Thus, Ply activity must be maintained at optimal levels. We develop a highly sensitive assay to monitor endosomal disruption using NanoBiT-Nanobody, which shows that the pneumococcal sialidase NanA can fine-tune Ply activity by trimming sialic acid from cell-membrane-bound glycans. In addition, oseltamivir, an influenza A virus sialidase inhibitor, promotes Ply-induced endosomal disruption and cytotoxicity by inhibiting NanA activity in vitro and greater tissue damage and bacterial clearance in vivo. Our findings provide a foundation for innovative therapeutic strategies for severe pneumococcal infections by exploiting the duality of Ply activity.
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Affiliation(s)
- Sayaka Shizukuishi
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan; Department of Microbiology, Yokohama City University Graduate School of Medicine, Kanagawa, Japan
| | - Michinaga Ogawa
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan.
| | - Eisuke Kuroda
- Department of Transformative Infection Control Development Studies, Osaka University Graduate School of Medicine, Osaka, Japan; Division of Fostering Required Medical Human Resources, Center for Infectious Disease Education and Research (CiDER), Osaka University, Osaka, Japan
| | - Shigeto Hamaguchi
- Division of Fostering Required Medical Human Resources, Center for Infectious Disease Education and Research (CiDER), Osaka University, Osaka, Japan; Department of Transformative Analysis for Human Specimen, Osaka University Graduate School of Medicine, Osaka, Japan; Division of Infection Control and Prevention, Osaka University Hospital, Osaka, Japan
| | - Chisato Sakuma
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Soichiro Kakuta
- Laboratory of Morphology and Image Analysis, Biomedical Research Core Facilities, Juntendo University Graduate School of Medicine, Tokyo, Japan; Department of Cellular and Molecular Neuropathology, Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Isei Tanida
- Department of Cellular and Molecular Neuropathology, Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yasuo Uchiyama
- Department of Cellular and Molecular Neuropathology, Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yukihiro Akeda
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Akihide Ryo
- Department of Microbiology, Yokohama City University Graduate School of Medicine, Kanagawa, Japan; Department of Virology III, National Institute of Infectious Diseases, Tokyo, Japan
| | - Makoto Ohnishi
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
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5
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Malmsheimer S, Grin I, Bohn E, Franz-Wachtel M, Macek B, Sahr T, Smollich F, Chetrit D, Meir A, Roy C, Buchrieser C, Wagner S. The T4bSS of Legionella features a two-step secretion pathway with an inner membrane intermediate for secretion of transmembrane effectors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.14.584949. [PMID: 38559167 PMCID: PMC10980071 DOI: 10.1101/2024.03.14.584949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
To promote intracellular survival and infection, Legionella spp. translocate hundreds of effector proteins into eukaryotic host cells using a type IV b protein secretion system (T4bSS). T4bSS are well known to translocate soluble as well as transmembrane domain-containing effector proteins (TMD-effectors) but the mechanisms of secretion are still poorly understood. Herein we investigated the secretion of hydrophobic TMD-effectors, of which about 80 were previously reported to be encoded by L. pneumophila. A proteomic analysis of fractionated membranes revealed that TMD-effectors are targeted to and inserted into the bacterial inner membranes of L. pneumophila independent of the presence of a functional T4bSS. While the T4bSS chaperones IcmS and IcmW were critical for secretion of all tested TMD-effectors, they did not influence inner membrane targeting of these proteins. As for soluble effector proteins, translocation of TMD-effectors into host cells depended on a C-terminal secretion signal and this signal needed to be presented towards the cytoplasmic side of the inner membrane. A different secretion behavior of TMD- and soluble effectors and the need for small periplasmic loops within TMD-effectors provided strong evidence that TMD-effectors are secreted in a two-step secretion process: Initially, an inner membrane intermediate is formed, that is extracted towards the cytoplasmic side, possibly by the help of the type IV coupling protein complex and subsequently secreted into eukaryotic host cells by the T4bSS core complex. Overall, our study highlights the amazing versatility of T4bSS to secrete soluble and TMD-effectors from different subcellular locations of the bacterial cell.
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Affiliation(s)
- Silke Malmsheimer
- University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Section of Cellular and Molecular Microbiology, Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
- Current address: Institut de Recherche en Infectiologie de Montpellier, Equipe Kremer, UMR 9004 - CNRS / UM, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Iwan Grin
- University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Section of Cellular and Molecular Microbiology, Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
| | - Erwin Bohn
- University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Institute of Medical Microbiology and Hygiene, Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
| | - Mirita Franz-Wachtel
- University of Tübingen, Proteome Center Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Boris Macek
- University of Tübingen, Proteome Center Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Tobias Sahr
- Institute Pasteur, Université Paris Cité, Biologie des Bactéries Intracellulaires, 75015 Paris, France
| | - Fabian Smollich
- University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Section of Cellular and Molecular Microbiology, Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
| | - David Chetrit
- Yale University, Department of Microbial Pathogenesis, 295 Congress Avenue, New Haven, CT 06536-0812, USA
| | - Amit Meir
- Yale University, Department of Microbial Pathogenesis, 295 Congress Avenue, New Haven, CT 06536-0812, USA
- Birkbeck Institute of Structural and Molecular Biology, Birkbeck and UCL, Malet Street, London WC1E 7HX, UK
- Current address: University of Glasgow, MRC Centre for Virus Research, School of Infection and Immunity, Glasgow, UK
| | - Craig Roy
- Yale University, Department of Microbial Pathogenesis, 295 Congress Avenue, New Haven, CT 06536-0812, USA
| | - Carmen Buchrieser
- Institute Pasteur, Université Paris Cité, Biologie des Bactéries Intracellulaires, 75015 Paris, France
| | - Samuel Wagner
- University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Section of Cellular and Molecular Microbiology, Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
- Excellence Cluster "Controlling Microbes to Fight Infections" (CMFI), Elfriede-Aulhorn-Str. 6, 72076 Tébingen, Germany
- German Center for Infection Research (DZIF), partner-site Tübingen, Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
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6
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Manigat F, Connell LB, Stewart BN, LePabic AR, Tessier CJG, Emlaw JR, Calvert ND, Rössl A, Shuhendler AJ, daCosta CJB, Campbell-Valois FX. pUdOs: Concise Plasmids for Bacterial and Mammalian Cells. ACS Synth Biol 2024; 13:485-497. [PMID: 38235654 PMCID: PMC10878396 DOI: 10.1021/acssynbio.3c00408] [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: 07/06/2023] [Revised: 11/22/2023] [Accepted: 11/28/2023] [Indexed: 01/19/2024]
Abstract
The plasmids from the Université d'Ottawa (pUdOs) are 28 small plasmids each comprising one of four origins of replication and one of seven selection markers, which together afford flexible use in Escherichia coli and several related gram-negative bacteria. The promoterless multicloning site is insulated from upstream spurious promoters by strong transcription terminators and contains type IIP or IIS restriction sites for conventional or Golden Gate cloning. pUdOs can be converted into efficient expression vectors through the insertion of a promoter at the user's discretion. For example, we demonstrate the utility of pUdOs as the backbone for an improved version of a Type III Secretion System reporter in Shigella. In addition, we derive a series of pUdO-based mammalian expression vectors, affording distinct levels of expression and transfection efficiency comparable to commonly used mammalian expression plasmids. Thus, pUdOs could advantageously replace traditional plasmids in a wide variety of cell types and applications.
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Affiliation(s)
- France
O. Manigat
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Louise B. Connell
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Brittany N. Stewart
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Abdel-Rahman LePabic
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Christian J. G. Tessier
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Johnathon R. Emlaw
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Nicholas D. Calvert
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Anthony Rössl
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Adam J. Shuhendler
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- University
of Ottawa Heart Institute, Ottawa, Ontario K1Y 4W7, Canada
| | - Corrie J. B. daCosta
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - François-Xavier Campbell-Valois
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- Centre
for Infection, Immunity and Inflammation, Department of Biochemistry,
Microbiology and Immunology, University
of Ottawa, Ottawa, Ontario K1N 6N5, Canada
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7
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Miao P, Zhou JM, Wang W. A self-assembling split Nano luciferase-based assay for investigating Pseudomonas syringae effector secretion. STRESS BIOLOGY 2024; 4:14. [PMID: 38363371 PMCID: PMC10873255 DOI: 10.1007/s44154-024-00152-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 01/28/2024] [Indexed: 02/17/2024]
Abstract
Many Gram-negative pathogens employ the type III secretion system (T3SS) to deliver effector proteins into host cells, thereby modulating host cellular processes and suppressing host immunity to facilitate pathogenesis and colonization. In this study, we developed a straightforward, rapid, and quantitative method for detecting T3SS-mediated translocation of Pseudomonas syringae effectors using a self-assembling split Nano luciferase (Nluc)-based reporter system. It was demonstrated that this system can detect effector secretion in vitro with an exceptionally high signal-to-noise ratio and sensitivity, attributed to the strong affinity between the split domains of Nluc and the intense luminescence generated by functional Nluc. During natural infections, effectors fused to a small C-terminal fragment of Nluc were successfully translocated into plant cells and retained their virulence functions. Furthermore, upon infection of plants expressing the N-terminal fragment of Nluc with these P. syringae strains, functional Nluc proteins were spontaneously assembled and produced bright luminescence, demonstrating that this system enables the straightforward and rapid assessment of P. syringae T3SS-mediated effector translocation during natural infections. In conclusion, the self-assembling split Nluc-based reporting system developed in this study is suitable for efficient in vitro and in planta detection of effectors secreted via T3SS.
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Affiliation(s)
- Pei Miao
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- Yazhouwan National Laboratory, Sanya, 572024, China
| | - Jian-Min Zhou
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
- Yazhouwan National Laboratory, Sanya, 572024, China
| | - Wei Wang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China.
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8
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Guo H, Geddes EJ, Opperman TJ, Heuck AP. Cell-Based Assay to Determine Type 3 Secretion System Translocon Assembly in Pseudomonas aeruginosa Using Split Luciferase. ACS Infect Dis 2023; 9:2652-2664. [PMID: 37978950 DOI: 10.1021/acsinfecdis.3c00482] [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] [Indexed: 11/19/2023]
Abstract
Multi-drug-resistant Pseudomonas aeruginosa poses a serious threat to hospitalized patients. This organism expresses an arsenal of virulence factors that enables it to readily establish infections and disseminate in the host. The Type 3 secretion system (T3SS) and its associated effectors play a crucial role in the pathogenesis of P. aeruginosa, making them attractive targets for the development of novel therapeutic agents. The T3SS translocon, composed of PopD and PopB, is an essential component of the T3SS secretion apparatus. In the properly assembled translocon, the N-terminus of PopD protrudes into the cytoplasm of the target mammalian cell, which can be exploited as a molecular indicator of functional translocon assembly. In this article, we describe a novel whole-cell-based assay that employs the split NanoLuc luciferase detection system to provide a readout for translocon assembly. The assay demonstrates a favorable signal/noise ratio (13.6) and robustness (Z' = 0.67), making it highly suitable for high-throughput screening of small-molecule inhibitors targeting T3SS translocon assembly.
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Affiliation(s)
- Hanling Guo
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Emily J Geddes
- Microbiotix, Inc., Worcester, Massachusetts 01605, United States
| | | | - Alejandro P Heuck
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003, United States
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003, United States
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9
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Choi IY, Oh JH, Wang Z, van Pijkeren JP. Bioluminescent monitoring of recombinant lactic acid bacteria and their products. mBio 2023; 14:e0119723. [PMID: 37668408 PMCID: PMC10653940 DOI: 10.1128/mbio.01197-23] [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: 05/09/2023] [Accepted: 06/29/2023] [Indexed: 09/06/2023] Open
Abstract
IMPORTANCE Lactic acid bacteria constitute a genetically diverse group of microorganisms with significant roles in the food industry, biotechnology, agriculture, and medicine. A core understanding of bacterial physiology in diverse environments is crucial to select and develop bacteria for industrial and medical applications. However, there is a lack of versatile tools to track (recombinant) protein production in lactic acid bacteria. In this study, we adapted a peptide-based bioluminescent tagging system that is functional across multiple genera and species. This system enables tracking of tagged proteins both in vitro and in situ, while it also can be used to enumerate recombinant bacteria from the mouse gastrointestinal tract with accuracy comparable to that of conventional plate counts. Our work expands the lactic acid bacteria genetic toolbox and will facilitate researchers in industry and academia with opportunities to monitor microbes and proteins under different physiologically relevant conditions.
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Affiliation(s)
- In Young Choi
- Department of Food Science, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jee-Hwan Oh
- Department of Food Science, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Zhiying Wang
- Department of Food Science, University of Wisconsin-Madison, Madison, Wisconsin, USA
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10
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Navarrete KM, Bumba L, Prudnikova T, Malcova I, Allsop TR, Sebo P, Kamanova J. BopN is a Gatekeeper of the Bordetella Type III Secretion System. Microbiol Spectr 2023; 11:e0411222. [PMID: 37036369 PMCID: PMC10269732 DOI: 10.1128/spectrum.04112-22] [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: 10/11/2022] [Accepted: 03/17/2023] [Indexed: 04/11/2023] Open
Abstract
The classical Bordetella species infect the respiratory tract of mammals. While B. bronchiseptica causes rather chronic respiratory infections in a variety of mammals, the human-adapted species B. pertussis and B. parapertussisHU cause an acute respiratory disease known as whooping cough or pertussis. The virulence factors include a type III secretion system (T3SS) that translocates effectors BteA and BopN into host cells. However, the regulatory mechanisms underlying the secretion and translocation activity of T3SS in bordetellae are largely unknown. We have solved the crystal structure of BopN of B. pertussis and show that it is similar to the structures of gatekeepers that control access to the T3SS channel from the bacterial cytoplasm. We further found that BopN accumulates at the cell periphery at physiological concentrations of calcium ions (2 mM) that inhibit the secretion of BteA and BopN. Deletion of the bopN gene in B. bronchiseptica increased secretion of the BteA effector into calcium-rich medium but had no effect on secretion of the T3SS translocon components BopD and BopB. Moreover, the ΔbopN mutant secreted approximately 10-fold higher amounts of BteA into the medium of infected cells than the wild-type bacteria, but it translocated lower amounts of BteA into the host cell cytoplasm. These data demonstrate that BopN is a Bordetella T3SS gatekeeper required for regulated and targeted translocation of the BteA effector through the T3SS injectisome into host cells. IMPORTANCE The T3SS is utilized by many Gram-negative bacteria to deliver effector proteins from bacterial cytosol directly into infected host cell cytoplasm in a regulated and targeted manner. Pathogenic bordetellae use the T3SS to inject the BteA and BopN proteins into infected cells and upregulate the production of the anti-inflammatory cytokine interleukin-10 (IL-10) to evade host immunity. Previous studies proposed that BopN acted as an effector in host cells. In this study, we report that BopN is a T3SS gatekeeper that regulates the secretion and translocation activity of Bordetella T3SS.
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Affiliation(s)
- Kevin Munoz Navarrete
- Laboratory of Infection Biology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ladislav Bumba
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Tatyana Prudnikova
- Faculty of Science, University of South Bohemia in Ceske Budejovice, Ceske Budejovice, Czech Republic
| | - Ivana Malcova
- Laboratory of Infection Biology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Tania Romero Allsop
- Laboratory of Infection Biology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Peter Sebo
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jana Kamanova
- Laboratory of Infection Biology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
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11
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Schott S, Scheuer R, Ermoli F, Glatter T, Evguenieva-Hackenberg E, Diepold A. A ParDE toxin-antitoxin system is responsible for the maintenance of the Yersinia virulence plasmid but not for type III secretion-associated growth inhibition. Front Cell Infect Microbiol 2023; 13:1166077. [PMID: 37228670 PMCID: PMC10203498 DOI: 10.3389/fcimb.2023.1166077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 04/20/2023] [Indexed: 05/27/2023] Open
Abstract
Many Gram-negative pathogens utilize the type III secretion system (T3SS) to translocate virulence-promoting effector proteins into eukaryotic host cells. The activity of this system results in a severe reduction of bacterial growth and division, summarized as secretion-associated growth inhibition (SAGI). In Yersinia enterocolitica, the T3SS and related proteins are encoded on a virulence plasmid. We identified a ParDE-like toxin-antitoxin system on this virulence plasmid in genetic proximity to yopE, encoding a T3SS effector. Effectors are strongly upregulated upon activation of the T3SS, indicating a potential role of the ParDE system in the SAGI or maintenance of the virulence plasmid. Expression of the toxin ParE in trans resulted in reduced growth and elongated bacteria, highly reminiscent of the SAGI. Nevertheless, the activity of ParDE is not causal for the SAGI. T3SS activation did not influence ParDE activity; conversely, ParDE had no impact on T3SS assembly or activity itself. However, we found that ParDE ensures the presence of the T3SS across bacterial populations by reducing the loss of the virulence plasmid, especially under conditions relevant to infection. Despite this effect, a subset of bacteria lost the virulence plasmid and regained the ability to divide under secreting conditions, facilitating the possible emergence of T3SS-negative bacteria in late acute and persistent infections.
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Affiliation(s)
- Saskia Schott
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Robina Scheuer
- Department of Microbiology and Molecular Biology, Justus Liebig University Gießen, Gießen, Germany
| | - Francesca Ermoli
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Timo Glatter
- Core Facility for Mass spectrometry & Proteomics, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | | | - Andreas Diepold
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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12
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Eggers O, Renschler FA, Michalek LA, Wackler N, Walter E, Smollich F, Klein K, Sonnabend MS, Egle V, Angelov A, Engesser C, Borisova M, Mayer C, Schütz M, Bohn E. YgfB increases β-lactam resistance in Pseudomonas aeruginosa by counteracting AlpA-mediated ampDh3 expression. Commun Biol 2023; 6:254. [PMID: 36894667 PMCID: PMC9998450 DOI: 10.1038/s42003-023-04609-4] [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: 07/05/2022] [Accepted: 02/17/2023] [Indexed: 03/11/2023] Open
Abstract
YgfB-mediated β-lactam resistance was recently identified in multi drug resistant Pseudomonas aeruginosa. We show that YgfB upregulates expression of the β-lactamase AmpC by repressing the function of the regulator of the programmed cell death pathway AlpA. In response to DNA damage, the antiterminator AlpA induces expression of the alpBCDE autolysis genes and of the peptidoglycan amidase AmpDh3. YgfB interacts with AlpA and represses the ampDh3 expression. Thus, YgfB indirectly prevents AmpDh3 from reducing the levels of cell wall-derived 1,6-anhydro-N-acetylmuramyl-peptides, required to induce the transcriptional activator AmpR in promoting the ampC expression and β-lactam resistance. Ciprofloxacin-mediated DNA damage induces AlpA-dependent production of AmpDh3 as previously shown, which should reduce β-lactam resistance. YgfB, however, counteracts the β-lactam enhancing activity of ciprofloxacin by repressing ampDh3 expression and lowering the benefits of this drug combination. Altogether, YgfB represents an additional player in the complex regulatory network of AmpC regulation.
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Affiliation(s)
- Ole Eggers
- Institute for Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Fabian A Renschler
- Institute for Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany
- German Centre for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Lydia Anita Michalek
- Institute for Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Noelle Wackler
- Institute for Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Elias Walter
- Institute for Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Fabian Smollich
- Institute for Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Kristina Klein
- Institute for Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Michael S Sonnabend
- Institute for Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen (NCCT), Institute for Medical Microbiology and Hygiene, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Valentin Egle
- Institute for Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany
- Cluster of Excellence "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen, Germany
| | - Angel Angelov
- NGS Competence Center Tübingen (NCCT), Institute for Medical Microbiology and Hygiene, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Christina Engesser
- NGS Competence Center Tübingen (NCCT), Institute for Medical Microbiology and Hygiene, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Marina Borisova
- Cluster of Excellence "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen, Germany
- Department of Biology, Organismic Interactions/Glycobiology, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Christoph Mayer
- Cluster of Excellence "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen, Germany
- Department of Biology, Organismic Interactions/Glycobiology, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Monika Schütz
- Institute for Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany
- German Centre for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Erwin Bohn
- Institute for Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany.
- German Centre for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany.
- Cluster of Excellence "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen, Germany.
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13
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S-Series Coelenterazine-Driven Combinatorial Bioluminescence Imaging Systems for Mammalian Cells. Int J Mol Sci 2023; 24:ijms24021420. [PMID: 36674934 PMCID: PMC9865520 DOI: 10.3390/ijms24021420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/07/2023] [Accepted: 01/09/2023] [Indexed: 01/12/2023] Open
Abstract
A unique combinatorial bioluminescence (BL) imaging system was developed for determining molecular events in mammalian cells with various colors and BL intensity patterns. This imaging system consists of one or multiple reporter luciferases and a series of novel coelenterazine (CTZ) analogues named "S-series". For this study, ten kinds of novel S-series CTZ analogues were synthesized and characterized concerning the BL intensities, spectra, colors, and specificity of various marine luciferases. The characterization revealed that the S-series CTZ analogues luminesce with blue-to-orange-colored BL spectra with marine luciferases, where the most red-shifted BL spectrum peaked at 583 nm. The colors completed a visible light color palette with those of our precedent C-series CTZ analogues. The synthesized substrates S1, S5, S6, and S7 were found to have a unique specificity with marine luciferases, such as R86SG, NanoLuc (shortly, NLuc), and ALuc16. They collectively showed unique BL intensity patterns to identify the marine luciferases together with colors. The marine luciferases, R86SG, NLuc, and ALuc16, were multiplexed into multi-reporter systems, the signals of which were quantitatively unmixed with the specific substrates. When the utility was applied to a single-chain molecular strain probe, the imaging system simultaneously reported three different optical indexes for a ligand, i.e., unique BL intensity and color patterns for identifying the reporters, together with the ligand-specific fold intensities in mammalian cells. This study directs a new combinatorial BL imaging system to specific image molecular events in mammalian cells with multiple optical indexes.
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14
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Geethakumari AM, Ahmed WS, Rasool S, Fatima A, Nasir Uddin SM, Aouida M, Biswas KH. A genetically encoded BRET-based SARS-CoV-2 M pro protease activity sensor. Commun Chem 2022; 5:117. [PMID: 36187754 PMCID: PMC9516532 DOI: 10.1038/s42004-022-00731-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 09/07/2022] [Indexed: 01/27/2023] Open
Abstract
The main protease, Mpro, is critical for SARS-CoV-2 replication and an appealing target for designing anti-SARS-CoV-2 agents. Therefore, there is a demand for the development of improved sensors to monitor its activity. Here, we report a pair of genetically encoded, bioluminescence resonance energy transfer (BRET)-based sensors for detecting Mpro proteolytic activity in live cells as well as in vitro. The sensors were generated by sandwiching peptides containing the Mpro N-terminal autocleavage sites, either AVLQSGFR (short) or KTSAVLQSGFRKME (long), in between the mNeonGreen and NanoLuc proteins. Co-expression of the sensors with Mpro in live cells resulted in their cleavage while mutation of the critical C145 residue (C145A) in Mpro completely abrogated their cleavage. Additionally, the sensors recapitulated the inhibition of Mpro by the well-characterized pharmacological agent GC376. Further, in vitro assays with the BRET-based Mpro sensors revealed a molecular crowding-mediated increase in the rate of Mpro activity and a decrease in the inhibitory potential of GC376. The sensors developed here will find direct utility in studies related to drug discovery targeting the SARS-CoV-2 Mpro and functional genomics application to determine the effect of sequence variation in Mpro.
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Affiliation(s)
- Anupriya M. Geethakumari
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
| | - Wesam S. Ahmed
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
| | - Saad Rasool
- Division of Genomics and Precision Medicine, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
| | - Asma Fatima
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
| | - S. M. Nasir Uddin
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
| | - Mustapha Aouida
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
| | - Kabir H. Biswas
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
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15
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Pierrat X, Pham A, Wong JPH, Al-Mayyah Z, Persat A. Engineering Agrobacterium tumefaciens Adhesion to Target Cells. ACS Synth Biol 2022; 11:2662-2671. [PMID: 35881049 DOI: 10.1021/acssynbio.2c00069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Agrobacterium tumefaciens is a plant pathogen commonly repurposed for genetic modification of crops. Despite its versatility, it remains inefficient at transferring DNA to many hosts, including to animal cells. Like many pathogens, physical contact between A. tumefaciens and host cells promotes infection efficacy. Thus, improving the strength and specificity of A. tumefaciens to target cells has the potential for enhancing DNA transfer for biotechnological and therapeutic purposes. Here, we demonstrate a methodology for engineering genetically encoded exogeneous adhesins at the surface of A. tumefaciens. We identified an autotransporter gene we named Aat that is predicted to show canonical β-barrel and passenger domains. We engineered the β-barrel scaffold and linker (Aatβ) to display synthetic adhesins susceptible to rewire A. tumefaciens to alternative host targets. As a proof of concept, we leveraged the versatility of a VHH domain to rewire A. tumefaciens adhesion to yeast and mammalian hosts displaying a GFP target receptor. Finally, to demonstrate how synthetic A. tumefaciens adhesion can improve transfer to host cells, we showed improved protein translocation into HeLa cells using a sensitive split luciferase reporter system. Engineering A. tumefaciens adhesion has therefore a strong potential in generating complex heterogeneous cellular assemblies and in improving DNA transfer efficiency against non-natural hosts.
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Affiliation(s)
- Xavier Pierrat
- School of Life Sciences, Institute of Bioengineering and Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Alix Pham
- School of Life Sciences, Institute of Bioengineering and Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Jeremy P H Wong
- School of Life Sciences, Institute of Bioengineering and Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Zainebe Al-Mayyah
- School of Life Sciences, Institute of Bioengineering and Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Alexandre Persat
- School of Life Sciences, Institute of Bioengineering and Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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16
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McArthur N, Cruz-Teran C, Thatavarty A, Reeves GT, Rao BM. Experimental and Analytical Framework for "Mix-and-Read" Assays Based on Split Luciferase. ACS OMEGA 2022; 7:24551-24560. [PMID: 35874239 PMCID: PMC9301641 DOI: 10.1021/acsomega.2c02319] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The use of immunodetection assays including the widely used enzyme-linked immunosorbent assay (ELISA) in applications such as point-of-care detection is often limited by the need for protein immobilization and multiple binding and washing steps. Here, we describe an experimental and analytical framework for the development of simple and modular "mix-and-read" enzymatic complementation assays based on split luciferase that enable sensitive detection and quantification of analytes in solution. In this assay, two engineered protein binders targeting nonoverlapping epitopes on the target analyte were each fused to nonactive fragments of luciferase to create biosensor probes. Binding proteins to two model targets, lysozyme and Sso6904, were isolated from a combinatorial library of Sso7d mutants using yeast surface display. In the presence of the analyte, probes were brought into close proximity, reconstituting enzymatic activity of luciferase and enabling detection of low picomolar concentrations of the analyte by chemiluminescence. Subsequently, we constructed an equilibrium binding model that relates binding affinities of the binding proteins for the target, assay parameters such as the concentrations of probes used, and assay performance (limit of detection and concentration range over which the target can be quantified). Overall, our experimental and analytical framework provides the foundation for the development of split luciferase assays for detection and quantification of various targets.
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Affiliation(s)
- Nikki McArthur
- Department
of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Carlos Cruz-Teran
- Department
of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Apoorva Thatavarty
- Department
of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Gregory T. Reeves
- Department
of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
- Interdisciplinary
Program in Genetics, Texas A&M University, College Station, Texas 77843, United States
| | - Balaji M. Rao
- Department
of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
- Golden
LEAF Biomanufacturing Training and Education Center (BTEC), North Carolina State University, Raleigh, North Carolina 27695, United States
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17
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Fromm K, Boegli A, Ortelli M, Wagner A, Bohn E, Malmsheimer S, Wagner S, Dehio C. Bartonella taylorii: A Model Organism for Studying Bartonella Infection in vitro and in vivo. Front Microbiol 2022; 13:913434. [PMID: 35910598 PMCID: PMC9336547 DOI: 10.3389/fmicb.2022.913434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 05/05/2022] [Indexed: 11/13/2022] Open
Abstract
Bartonella spp. are Gram-negative facultative intracellular pathogens that infect diverse mammals and cause a long-lasting intra-erythrocytic bacteremia in their natural host. These bacteria translocate Bartonella effector proteins (Beps) into host cells via their VirB/VirD4 type 4 secretion system (T4SS) in order to subvert host cellular functions, thereby leading to the downregulation of innate immune responses. Most studies on the functional analysis of the VirB/VirD4 T4SS and the Beps were performed with the major zoonotic pathogen Bartonella henselae for which efficient in vitro infection protocols have been established. However, its natural host, the cat, is unsuitable as an experimental infection model. In vivo studies were mostly confined to rodent models using rodent-specific Bartonella species, while the in vitro infection protocols devised for B. henselae are not transferable for those pathogens. The disparities of in vitro and in vivo studies in different species have hampered progress in our understanding of Bartonella pathogenesis. Here we describe the murine-specific strain Bartonella taylorii IBS296 as a new model organism facilitating the study of bacterial pathogenesis both in vitro in cell cultures and in vivo in laboratory mice. We implemented the split NanoLuc luciferase-based translocation assay to study BepD translocation through the VirB/VirD4 T4SS. We found increased effector-translocation into host cells if the bacteria were grown on tryptic soy agar (TSA) plates and experienced a temperature shift immediately before infection. The improved infectivity in vitro was correlating to an upregulation of the VirB/VirD4 T4SS. Using our adapted infection protocols, we showed BepD-dependent immunomodulatory phenotypes in vitro. In mice, the implemented growth conditions enabled infection by a massively reduced inoculum without having an impact on the course of the intra-erythrocytic bacteremia. The established model opens new avenues to study the role of the VirB/VirD4 T4SS and the translocated Bep effectors in vitro and in vivo.
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Affiliation(s)
- Katja Fromm
- Biozentrum, University of Basel, Basel, Switzerland
| | - Alexandra Boegli
- Department of Biochemistry, Faculty of Biology and Medicine, Université de Lausanne, Epalinges, Switzerland
| | | | | | - Erwin Bohn
- Institute of Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Silke Malmsheimer
- Section of Cellular and Molecular Microbiology, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Samuel Wagner
- Section of Cellular and Molecular Microbiology, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
- Excellence Cluster “Controlling Microbes to Fight Infections” (CMFI), Tübingen, Germany
- Partner-site Tübingen, German Center for Infection Research (DZIF), Tübingen, Germany
| | - Christoph Dehio
- Biozentrum, University of Basel, Basel, Switzerland
- *Correspondence: Christoph Dehio,
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18
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Li J, Xu M, Sun J, Li J, Chen J, Chen Q, Chen J. Rapid titration of recombinant baculoviruses based on NanoLuc secretion in early infection. J Virol Methods 2022; 307:114565. [PMID: 35728698 DOI: 10.1016/j.jviromet.2022.114565] [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: 03/21/2022] [Revised: 05/18/2022] [Accepted: 06/08/2022] [Indexed: 11/26/2022]
Abstract
The baculovirus expression vector system has become a powerful tool for recombinant protein production and gene delivery. However, existing titration methods for baculovirus are not economical in terms of test time and cost. A titration method based on NanoLuc secretion that allows for titration of recombinant baculoviruses at 4 h post infection (hpi) is described. In the assay, the envelop protein GP64 signal peptide-guided NanoLuc was secreted into the culture medium in proportion to the virus amount during early infection under combined control by the homologous region 5 (hr5) enhancer and the promoter of immediate early gene 1 (ie1) plus L21. Two timepoint standard curves of luciferase activity to virus titers of 5-9 logs were established with excellent linearity and correlation coefficients (slope = 1.050, R2 ≥ 0.9969) using a secretory Nanoluc (secrNluc) - inserted standard baculovirus. Through the assay, the titers of three recombinant viruses prepared independently were calculated by directly measuring luciferase activity in the supernatant at 4 and 6 hpi, with greater accuracy compared to the endpoint dilution assay. These results show the efficacy of this proposed method as a streamlined assay for rapidly titrating recombinant baculoviruses.
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Affiliation(s)
- Jige Li
- Department of Biopharmacy, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Meng Xu
- Department of Biopharmacy, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Juan Sun
- Department of Biopharmacy, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Junjun Li
- Institute of Molecular Enzymology and School of Biology & Basic Medical Sciences, Medical College, Soochow University, Suzhou 215123, China
| | - Jianqing Chen
- Department of Biopharmacy, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Qin Chen
- Department of Biopharmacy, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Jian Chen
- Department of Biopharmacy, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China.
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19
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Recent Advancements in Tracking Bacterial Effector Protein Translocation. Microorganisms 2022; 10:microorganisms10020260. [PMID: 35208715 PMCID: PMC8876096 DOI: 10.3390/microorganisms10020260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 11/17/2022] Open
Abstract
Bacteria-host interactions are characterized by the delivery of bacterial virulence factors, i.e., effectors, into host cells where they counteract host immunity and exploit host responses allowing bacterial survival and spreading. These effectors are translocated into host cells by means of dedicated secretion systems such as the type 3 secretion system (T3SS). A comprehensive understanding of effector translocation in a spatio-temporal manner is of critical importance to gain insights into an effector’s mode of action. Various approaches have been developed to understand timing and order of effector translocation, quantities of translocated effectors and their subcellular localization upon translocation into host cells. Recently, the existing toolset has been expanded by newly developed state-of-the art methods to monitor bacterial effector translocation and dynamics. In this review, we elaborate on reported methods and discuss recent advances and shortcomings in this area of tracking bacterial effector translocation.
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20
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Pais SV, Westerhausen S, Bohn E, Wagner S. Analysis of SPI-1 Dependent Type III Secretion and Injection Using a NanoLuc Luciferase-Based Assay. Methods Mol Biol 2022; 2427:57-71. [PMID: 35619025 DOI: 10.1007/978-1-0716-1971-1_6] [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] [Indexed: 06/15/2023]
Abstract
Studies of bacterial protein secretion have relied on a variety of reporters that allow the tracking of secreted proteins. However, the lack of truly quantitative and highly sensitive reporters has hindered, in particular, the investigation of the kinetics of protein secretion. In this chapter, we describe a luminescence-based assay using NanoLuc luciferase to analyse secretion and injection into host cells of type III secretion (T3S) substrates encoded on Salmonella pathogenicity island-1 (SPI-1). This method has a very high sensitivity and high signal-to-noise ratio. Moreover, the simplicity of the protocol and the rapid determination and quantification of the luminescence makes it ideal for the monitoring of the kinetics of secretion but also convenient for high-throughput screenings. The protocols presented here include (1) Salmonella SPI-1 secretion assay, where the T3S substrates-NanoLuc fusions are detected by luminometry in the bacterial supernatant, and (2) Salmonella injection assays, using the split-Nanoluc (HiBiT/LgBiT) to monitor the injection of T3S substrates-HiBiT fusions into the host cells stably expressing LgBiT.
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Affiliation(s)
- Sara Vilela Pais
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
- Excellence Cluster Controlling Microbes to Fight Infections (CMFI), Tübingen, Germany
| | - Sibel Westerhausen
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Erwin Bohn
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
- Excellence Cluster Controlling Microbes to Fight Infections (CMFI), Tübingen, Germany
- Partner-site Tübingen, German Center for Infection Research (DZIF), Tübingen, Germany
| | - Samuel Wagner
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany.
- Excellence Cluster Controlling Microbes to Fight Infections (CMFI), Tübingen, Germany.
- Partner-site Tübingen, German Center for Infection Research (DZIF), Tübingen, Germany.
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21
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Development of a highly sensitive luciferase-based reporter system to study two-step protein secretion in cyanobacteria. J Bacteriol 2021; 204:e0050421. [PMID: 34898262 DOI: 10.1128/jb.00504-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cyanobacteria, ubiquitous oxygenic photosynthetic bacteria, interact with the environment and their surrounding microbiome through the secretion of a variety of small molecules and proteins. The release of these compounds is mediated by sophisticated multi-protein complexes, also known as secretion systems. Genomic analyses indicate that protein and metabolite secretion systems are widely found in cyanobacteria; however little is known regarding their function, regulation and secreted effectors. One such system, the type IVa pilus system (T4aPS), is responsible for the assembly of dynamic cell surface appendages, type IVa pili (T4aP), that mediate ecologically relevant processes such as phototactic motility, natural competence and adhesion. Several studies have suggested that the T4aPS can also act as a two-step protein secretion system in cyanobacteria akin to the homologous type II secretion system in heterotrophic bacteria. To determine whether the T4aP are involved in two-step secretion of non-pilin proteins, we developed a NanoLuc-based quantitative secretion reporter for the model cyanobacterium Synechocystis sp. PCC 6803. The NLuc reporter presented a wide dynamic range with at least one order of magnitude more sensitivity than traditional immunoblotting. Application of the reporter to a collection of Synechocystis T4aPS mutants demonstrated that the two-step secretion of NLuc is independent of T4aP. In addition, our data suggest that secretion differences typically observed in T4aPS mutants are likely due to a disruption of cell envelope homeostasis. This study opens the door to explore protein secretion in cyanobacteria further. Importance Protein secretion allows bacteria to interact and communicate with the external environment. Secretion is also biotechnologically relevant, where it is often beneficial to target proteins to the extracellular space. Due to a shortage of quantitative assays, many aspects of protein secretion are not understood. Here we introduce a NanoLuc (NLuc)-based secretion reporter in cyanobacteria. NLuc is highly sensitive and can be assayed rapidly and in small volumes. The NLuc reporter allowed us to clarify the role of type IVa pili in protein secretion and identify mutations that increase secretion yield. This study expands our knowledge on cyanobacterial secretion and offers a valuable tool for future studies of protein secretion systems in cyanobacteria.
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22
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Baatartsogt N, Kashiwakura Y, Hayakawa M, Kamoshita N, Hiramoto T, Mizukami H, Ohmori T. A sensitive and reproducible cell-based assay via secNanoLuc to detect neutralizing antibody against adeno-associated virus vector capsid. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 22:162-171. [PMID: 34485602 PMCID: PMC8397836 DOI: 10.1016/j.omtm.2021.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 06/04/2021] [Indexed: 12/19/2022]
Abstract
Most gene therapy clinical trials that systemically administered adeno-associated virus (AAV) vector enrolled only patients without anti-AAV-neutralizing antibodies. However, laboratory tests to measure neutralizing antibodies varied among clinical trials and have not been standardized. In this study, we attempted to improve the sensitivity and reproducibility of a cell-based assay to detect neutralizing antibodies and to determine the detection threshold to predict treatment efficacy. Application of the secreted type of NanoLuc and AAV receptor-expressing cells reduced the multiplicity of infection (MOI) for AAV transduction and improved the sensitivity to detect neutralizing antibodies with a low coefficient of variation, whereas the detection threshold could not be improved by the reduction of MOI to <100. After human immunoglobulin administration into mice at various doses, treatment with high-dose AAV8 vector enabled evasion of the inhibitory effect of neutralizing antibodies. Conversely, gene transduction was slightly influenced in the mice treated with low-dose AAV8 vector, even when neutralizing antibodies were determined to be negative in the assay. In conclusion, we developed a reliable and sensitive cell-based assay to measure neutralizing antibodies against AAV and found that the appropriate MOI to detect marginal neutralizing antibodies was 100. Other factors, including noninhibitory antibodies, marginally influence in vivo transduction at low vector doses.
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Affiliation(s)
- Nemekhbayar Baatartsogt
- Department of Biochemistry, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Yuji Kashiwakura
- Department of Biochemistry, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Morisada Hayakawa
- Department of Biochemistry, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Nobuhiko Kamoshita
- Department of Biochemistry, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Takafumi Hiramoto
- Department of Biochemistry, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Hiroaki Mizukami
- Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Tsukasa Ohmori
- Department of Biochemistry, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
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23
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Singh N, Kronenberger T, Eipper A, Weichel F, Franz-Wachtel M, Macek B, Wagner S. Conserved Salt Bridges Facilitate Assembly of the Helical Core Export Apparatus of a Salmonella enterica Type III Secretion System. J Mol Biol 2021; 433:167175. [PMID: 34303721 DOI: 10.1016/j.jmb.2021.167175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 11/27/2022]
Abstract
Virulence-associated type III secretion systems (T3SS) are utilized by Gram negative bacterial pathogens for injection of effector proteins into eukaryotic host cells. The transmembrane export apparatus at the core of T3SS is composed of a unique helical complex of the hydrophobic proteins SctR, SctS, SctT, and SctU. These components comprise a number of highly conserved charged residues within their hydrophobic domains. The structure of the closed state of the core complex SctR5S4T1 revealed that several of these residues form inter- and intramolecular salt bridges, some of which have to be broken for pore opening. Mutagenesis of individual residues was shown to compromise assembly or secretion of both, the virulence-associated and the related flagellar T3SS. However, the exact role of these conserved charged residues in the assembly and function of T3SS remains elusive. Here we performed an in-depth mutagenesis analysis of these residues in the T3SS of Salmonella Typhimurium, coupled to blue native PAGE, in vivo photocrosslinking and luciferase-based secretion assays. Our data show that these conserved salt bridges are not critical for assembly of the respective protein but rather facilitate the incorporation of the following subunit into the assembling complex. Our data also indicate that these conserved charged residues are critical for type III-dependent secretion and reveal a functional link between SctSE44 and SctTR204 and the cytoplasmic domain of SctU in gating the T3SS injectisome. Overall, our analysis provides an unprecedented insight into the delicate requirements for the assembly and function of the machinery at the core of T3SS.
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Affiliation(s)
- Nidhi Singh
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Thales Kronenberger
- University Hospital Tübingen, Department of Internal Medicine VIII, Tübingen, Germany; School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211 Kuopio, Finland
| | - Andrea Eipper
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Felix Weichel
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany; Partner-site Tübingen, German Center for Infection Research (DZIF), Tübingen, Germany
| | | | - Boris Macek
- Excellence Cluster "Controlling Microbes to Fight Infections" (CMFI), Tübingen, Germany; Proteome Center Tübingen, University of Tübingen, Tübingen, Germany
| | - Samuel Wagner
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany; Excellence Cluster "Controlling Microbes to Fight Infections" (CMFI), Tübingen, Germany; Partner-site Tübingen, German Center for Infection Research (DZIF), Tübingen, Germany.
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24
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Cover TL. Tracking bacterial effector protein delivery into host cells. Mol Microbiol 2021; 116:724-728. [PMID: 34250669 DOI: 10.1111/mmi.14784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 07/08/2021] [Indexed: 11/29/2022]
Abstract
Bacterial Type IV secretion systems (T4SSs) are a functionally heterogeneous group of nanomachines that can deliver substrates into a wide range of target cells. The Helicobacter pylori Cag T4SS has an important role in the pathogenesis of gastric cancer. CagA, the only effector protein known to be secreted by the H. pylori Cag T4SS, enters human gastric cells and causes alterations in intracellular signaling that are linked to cancer pathogenesis. Understanding the molecular mechanisms by which CagA is delivered into gastric cells has been hindered by the lack of robust methods for monitoring this process. A publication in this issue of Molecular Microbiology describes a split luciferase assay for monitoring T4SS-mediated translocation of CagA into host cells. The use of this translocation reporter allowed the quantification of CagA translocation in real-time assays, thereby facilitating the analysis of the kinetics of CagA delivery. This system also allowed the tracking of several types of CagA fusion proteins and confirmed that protein unfolding is important for secretion by the Cag T4SS. This commentary discusses T4SS-dependent delivery of H. pylori CagA into host cells and the use of the split luciferase system for monitoring bacterial protein secretion and delivery into target cells.
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Affiliation(s)
- Timothy L Cover
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA.,Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, USA
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25
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Lettl C, Haas R, Fischer W. Kinetics of CagA type IV secretion by Helicobacter pylori and the requirement for substrate unfolding. Mol Microbiol 2021; 116:794-807. [PMID: 34121254 DOI: 10.1111/mmi.14772] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/02/2021] [Accepted: 06/12/2021] [Indexed: 12/27/2022]
Abstract
Type IV secretion of effector proteins is an important principle for interaction of human pathogens with their target cells. The corresponding secretion systems may transport a multitude of effector proteins that have to be deployed in the respective spatiotemporal context, or only a single translocated protein, as in the case of the CagA effector protein produced by the human gastric pathogen Helicobacter pylori. For a more detailed analysis of the kinetics and mode of action of CagA type IV secretion by H. pylori, we describe here, a novel, highly sensitive split luciferase-based translocation reporter which can be easily adapted to different end-point or real-time measurements. Using this reporter, we showed that H. pylori cells are able to rapidly inject a limited amount of their CagA supply into cultured gastric epithelial cells. We have further employed the reporter system to address the question whether CagA has to be unfolded prior to translocation by the type IV secretion system. We showed that protein domains co-translocated with CagA as protein fusions are more readily tolerated as substrates than in other secretion systems, but also provide evidence that unfolding of effector proteins is a prerequisite for their transport.
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Affiliation(s)
- Clara Lettl
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Medical Faculty, LMU Munich, Munich, Germany.,Partner Site Munich, German Center for Infection Research (DZIF), Munich, Germany
| | - Rainer Haas
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Medical Faculty, LMU Munich, Munich, Germany.,Partner Site Munich, German Center for Infection Research (DZIF), Munich, Germany
| | - Wolfgang Fischer
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Medical Faculty, LMU Munich, Munich, Germany.,Partner Site Munich, German Center for Infection Research (DZIF), Munich, Germany
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26
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Meyer MD, Ryck JD, Goormachtig S, Van Damme P. Keeping in Touch with Type-III Secretion System Effectors: Mass Spectrometry-Based Proteomics to Study Effector-Host Protein-Protein Interactions. Int J Mol Sci 2020; 21:E6891. [PMID: 32961832 PMCID: PMC7555288 DOI: 10.3390/ijms21186891] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 01/03/2023] Open
Abstract
Manipulation of host cellular processes by translocated bacterial effectors is key to the success of bacterial pathogens and some symbionts. Therefore, a comprehensive understanding of effectors is of critical importance to understand infection biology. It has become increasingly clear that the identification of host protein targets contributes invaluable knowledge to the characterization of effector function during pathogenesis. Recent advances in mapping protein-protein interaction networks by means of mass spectrometry-based interactomics have enabled the identification of host targets at large-scale. In this review, we highlight mass spectrometry-driven proteomics strategies and recent advances to elucidate type-III secretion system effector-host protein-protein interactions. Furthermore, we highlight approaches for defining spatial and temporal effector-host interactions, and discuss possible avenues for studying natively delivered effectors in the context of infection. Overall, the knowledge gained when unravelling effector complexation with host factors will provide novel opportunities to control infectious disease outcomes.
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Affiliation(s)
- Margaux De Meyer
- Department of Biochemistry and Microbiology, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium; (M.D.M.); (J.D.R.)
- VIB Center for Medical Biotechnology, Technologiepark 75, 9052 Zwijnaarde, Belgium
| | - Joren De Ryck
- Department of Biochemistry and Microbiology, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium; (M.D.M.); (J.D.R.)
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Zwijnaarde, Belgium;
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052 Zwijnaarde, Belgium
| | - Sofie Goormachtig
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Zwijnaarde, Belgium;
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052 Zwijnaarde, Belgium
| | - Petra Van Damme
- Department of Biochemistry and Microbiology, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium; (M.D.M.); (J.D.R.)
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27
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LITESEC-T3SS - Light-controlled protein delivery into eukaryotic cells with high spatial and temporal resolution. Nat Commun 2020; 11:2381. [PMID: 32404906 PMCID: PMC7221075 DOI: 10.1038/s41467-020-16169-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 04/18/2020] [Indexed: 12/16/2022] Open
Abstract
Many bacteria employ a type III secretion system (T3SS) injectisome to translocate proteins into eukaryotic host cells. Although the T3SS can efficiently export heterologous cargo proteins, a lack of target cell specificity currently limits its application in biotechnology and healthcare. In this study, we exploit the dynamic nature of the T3SS to govern its activity. Using optogenetic interaction switches to control the availability of the dynamic cytosolic T3SS component SctQ, T3SS-dependent effector secretion can be regulated by light. The resulting system, LITESEC-T3SS (Light-induced translocation of effectors through sequestration of endogenous components of the T3SS), allows rapid, specific, and reversible activation or deactivation of the T3SS upon illumination. We demonstrate the light-regulated translocation of heterologous reporter proteins, and induction of apoptosis in cultured eukaryotic cells. LITESEC-T3SS constitutes a new method to control protein secretion and translocation into eukaryotic host cells with unparalleled spatial and temporal resolution.
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28
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Abstract
The independent naming of components of injectisome-type type III secretion systems in different bacterial species has resulted in considerable confusion, impeding accessibility of the literature and hindering communication between scientists of the same field. A unified nomenclature had been proposed by Hueck more than 20 years ago. It found little attention for many years, but usage was sparked again by recent reviews and an international type III secretion meeting in 2016. Here, we propose that the field consistently switches to an extended version of this nomenclature to be no longer lost in translation.
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