1
|
Sirisaengtaksin N, O'Donoghue EJ, Jabbari S, Roe AJ, Krachler AM. Bacterial outer membrane vesicles provide an alternative pathway for trafficking of Escherichia coli O157 type III secreted effectors to epithelial cells. mSphere 2023; 8:e0052023. [PMID: 37929984 PMCID: PMC10732017 DOI: 10.1128/msphere.00520-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 10/03/2023] [Indexed: 11/07/2023] Open
Abstract
IMPORTANCE Bacteria can package protein cargo into nanosized membrane blebs that are shed from the bacterial membrane and released into the environment. Here, we report that a type of pathogenic bacteria called enterohemorrhagic Escherichia coli O157 (EHEC) uses their membrane blebs (outer membrane vesicles) to package components of their type 3 secretion system and send them into host cells, where they can manipulate host signaling pathways including those involved in infection response, such as immunity. Usually, EHEC use a needle-like apparatus to inject these components into host cells, but packaging them into membrane blebs that get taken up by host cells is another way of delivery that can bypass the need for a functioning injection system.
Collapse
Affiliation(s)
- Natalie Sirisaengtaksin
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Eloise J. O'Donoghue
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Sara Jabbari
- School of Mathematics, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Andrew J. Roe
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Anne Marie Krachler
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| |
Collapse
|
2
|
Cassidy RM, Flores EM, Trinh Nguyen AK, Cheruvu SS, Uribe RA, Krachler AM, Odem MA. Systematic analysis of proximal midgut- and anorectal-originating contractions in larval zebrafish using event feature detection and supervised machine learning algorithms. Neurogastroenterol Motil 2023; 35:e14675. [PMID: 37743702 PMCID: PMC10841157 DOI: 10.1111/nmo.14675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 07/16/2023] [Accepted: 08/28/2023] [Indexed: 09/26/2023]
Abstract
BACKGROUND Zebrafish larvae are translucent, allowing in vivo analysis of gut development and physiology, including gut motility. While recent progress has been made in measuring gut motility in larvae, challenges remain which can influence results, such as how data are interpreted, opportunities for technical user error, and inconsistencies in methods. METHODS To overcome these challenges, we noninvasively introduced Nile Red fluorescent dye to fill the intraluminal gut space in zebrafish larvae and collected serial confocal microscopic images of gut fluorescence. We automated the detection of fluorescent-contrasted contraction events against the median-subtracted signal and compared it to manually annotated gut contraction events across anatomically defined gut regions. Supervised machine learning (multiple logistic regression) was then used to discriminate between true contraction events and noise. To demonstrate, we analyzed motility in larvae under control and reserpine-treated conditions. We also used automated event detection analysis to compare unfed and fed larvae. KEY RESULTS Automated analysis retained event features for proximal midgut-originating retrograde and anterograde contractions and anorectal-originating retrograde contractions. While manual annotation showed reserpine disrupted gut motility, machine learning only achieved equivalent contraction discrimination in controls and failed to accurately identify contractions after reserpine due to insufficient intraluminal fluorescence. Automated analysis also showed feeding had no effect on the frequency of anorectal-originating contractions. CONCLUSIONS & INFERENCES Automated event detection analysis rapidly and accurately annotated contraction events, including the previously neglected phenomenon of anorectal contractions. However, challenges remain to discriminate contraction events based on intraluminal fluorescence under treatment conditions that disrupt functional motility.
Collapse
Affiliation(s)
- Ryan M. Cassidy
- Brown Foundation Institute of Molecular Medicine, McGovern
Medical School at UTHealth, Houston, TX 77030, USA
| | - Erika M. Flores
- Department of Microbiology and Molecular Genetics, McGovern
Medical School at UTHealth, Houston, TX 77030, USA
| | - Anh K. Trinh Nguyen
- Department of Microbiology and Molecular Genetics, McGovern
Medical School at UTHealth, Houston, TX 77030, USA
| | - Sai S. Cheruvu
- Department of Integrative Biology and Pharmacology,
McGovern Medical School at UTHealth, Houston, TX 77030, USA
| | - Rosa A. Uribe
- Department of Biosciences, Rice University, Houston, TX
77005, USA
| | - Anne Marie Krachler
- Department of Microbiology and Molecular Genetics, McGovern
Medical School at UTHealth, Houston, TX 77030, USA
| | - Max A. Odem
- Department of Microbiology and Molecular Genetics, McGovern
Medical School at UTHealth, Houston, TX 77030, USA
| |
Collapse
|
3
|
Krachler AM, Sirisaengtaksin N, Monteith P, Paine CET, Coates CJ, Lim J. Defective phagocyte association during infection of Galleria mellonella with Yersinia pseudotuberculosis is detrimental to both insect host and microbe. Virulence 2021; 12:638-653. [PMID: 33550901 PMCID: PMC7889024 DOI: 10.1080/21505594.2021.1878672] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/13/2021] [Accepted: 01/15/2021] [Indexed: 11/03/2022] Open
Abstract
Adhesins facilitate bacterial colonization and invasion of host tissues and are considered virulence factors, but their impact on immune-mediated damage as a driver of pathogenesis remains unclear. Yersinia pseudotuberculosis encodes for a multivalent adhesion molecule (MAM), a mammalian cell entry (MCE) family protein and adhesin. MAMs are widespread in Gram-negative bacteria and enable enteric bacteria to colonize epithelial tissues. Their role in bacterial interactions with the host innate immune system and contribution to pathogenicity remains unclear. Here, we investigated howY. pseudotuberculosis MAM contributes to pathogenesis during infection of the Galleria mellonella insect model. We show that Y. pseudotuberculosis MAM is required for efficient bacterial binding and uptake by hemocytes, the host phagocytes. Y. pseudotuberculosis interactions with insect and mammalian phagocytes are determined by bacterial and host factors. Loss of MAM, and deficient microbe-phagocyte interaction, increased pathogenesis in G. mellonella. Diminished phagocyte association also led to increased bacterial clearance. Furthermore, Y. pseudotuberculosis that failed to engage phagocytes hyperactivated humoral immune responses, most notably melanin production. Despite clearing the pathogen, excessive melanization also increased phagocyte death and host mortality. Our findings provide a basis for further studies investigating how microbe- and host-factors integrate to drive pathogenesis in a tractable experimental system.
Collapse
Affiliation(s)
- Anne Marie Krachler
- Department of Microbiology and Molecular Genetics, University of Texas McGovern Medical School at Houston, Houston, TX, USA
| | - Natalie Sirisaengtaksin
- Department of Microbiology and Molecular Genetics, University of Texas McGovern Medical School at Houston, Houston, TX, USA
| | - Pauline Monteith
- Biological and Environmental Sciences, University of Stirling, Stirling, UK
| | - C. E. Timothy Paine
- School of Environmental and Rural Sciences, University of New England, Armidale, Australia
| | - Christopher J. Coates
- Department of Biosciences, College of Science, Swansea University, Swansea, Wales UK
| | - Jenson Lim
- Biological and Environmental Sciences, University of Stirling, Stirling, UK
| |
Collapse
|
4
|
Huebinger RM, Do DH, Carlson DL, Yao X, Stones DH, De Souza Santos M, Vaz DP, Keen E, Wolf SE, Minei JP, Francis KP, Orth K, Krachler AM. Bacterial adhesion inhibitor prevents infection in a rodent surgical incision model. Virulence 2021; 11:695-706. [PMID: 32490711 PMCID: PMC7550027 DOI: 10.1080/21505594.2020.1772652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Surgical site infection risk continues to increase due to lack of efficacy in current standard of care drugs. New methods to treat or prevent antibiotic-resistant bacterial infections are needed. Multivalent Adhesion Molecules (MAM) are bacterial adhesins required for virulence. We developed a bacterial adhesion inhibitor using recombinant MAM fragment bound to polymer scaffold, mimicking MAM7 display on the bacterial surface. Here, we test MAM7 inhibitor efficacy to prevent Gram-positive and Gram-negative infections. Using a rodent model of surgical infection, incision sites were infected with antibiotic-resistant bioluminescent strains of Staphylococcus aureus or Pseudomonas aeruginosa. Infections were treated with MAM7 inhibitor or control suspension. Bacterial abundance was quantified for nine days post infection. Inflammatory responses and histology were characterized using fixed tissue sections. MAM7 inhibitor treatment decreased burden of S. aureus and P. aeruginosa below detection threshold. Bacterial load of groups treated with control were significantly higher than MAM7 inhibitor-treated groups. Treatment with inhibitor reduced colonization of clinically-relevant pathogens in an in vivo model of surgical infection. Use of MAM7 inhibitor to block initial adhesion of bacteria to tissue in surgical incisions may reduce infection rates, presenting a strategy to mitigate overuse of antibiotics to prevent surgical site infections.
Collapse
Affiliation(s)
- R M Huebinger
- Department of Surgery, Division of General and Acute Care Surgery, University of Texas Southwestern Medical Center , Dallas, TX, USA
| | - D H Do
- Department of Surgery, Division of General and Acute Care Surgery, University of Texas Southwestern Medical Center , Dallas, TX, USA
| | - D L Carlson
- Department of Surgery, Division of General and Acute Care Surgery, University of Texas Southwestern Medical Center , Dallas, TX, USA
| | - X Yao
- Department of Surgery, Division of General and Acute Care Surgery, University of Texas Southwestern Medical Center , Dallas, TX, USA
| | - D H Stones
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham , Birmingham, UK.,University of Gloucestershire, School of Natural and Social Sciences , Cheltenham, UK
| | - M De Souza Santos
- Department of Molecular Biology, University of Texas Southwestern Medical Center , Dallas, TX, USA
| | - D P Vaz
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, McGovern Medical School , Houston, TX, USA
| | - E Keen
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham , Birmingham, UK
| | - S E Wolf
- Department of Surgery, Division of General and Acute Care Surgery, University of Texas Southwestern Medical Center , Dallas, TX, USA.,UTMB Department of Surgery, Shriners Hospitals for Children , Galveston, TX, USA
| | - J P Minei
- Department of Surgery, Division of General and Acute Care Surgery, University of Texas Southwestern Medical Center , Dallas, TX, USA
| | | | - K Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center , Dallas, TX, USA.,Department of Biochemistry, University of Texas Southwestern Medical Center , Dallas, TX, USA.,Howard Hughes Medical Institute, University of Texas Southwestern Medical Center , Dallas, TX, USA
| | - A M Krachler
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, McGovern Medical School , Houston, TX, USA
| |
Collapse
|
5
|
Flores EM, Nguyen AT, Odem MA, Eisenhoffer GT, Krachler AM. The zebrafish as a model for gastrointestinal tract-microbe interactions. Cell Microbiol 2020; 22:e13152. [PMID: 31872937 DOI: 10.1111/cmi.13152] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/07/2019] [Accepted: 12/19/2019] [Indexed: 02/06/2023]
Abstract
The zebrafish (Danio rerio) has become a widely used vertebrate model for bacterial, fungal, viral, and protozoan infections. Due to its genetic tractability, large clutch sizes, ease of manipulation, and optical transparency during early life stages, it is a particularly useful model to address questions about the cellular microbiology of host-microbe interactions. Although its use as a model for systemic infections, as well as infections localised to the hindbrain and swimbladder having been thoroughly reviewed, studies focusing on host-microbe interactions in the zebrafish gastrointestinal tract have been neglected. Here, we summarise recent findings regarding the developmental and immune biology of the gastrointestinal tract, drawing parallels to mammalian systems. We discuss the use of adult and larval zebrafish as models for gastrointestinal infections, and more generally, for studies of host-microbe interactions in the gut.
Collapse
Affiliation(s)
- Erika M Flores
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas.,M.D. Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas
| | - Anh T Nguyen
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas.,M.D. Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas
| | - Max A Odem
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas
| | - George T Eisenhoffer
- M.D. Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas.,Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Anne Marie Krachler
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas.,M.D. Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas
| |
Collapse
|
6
|
Fan Y, Thompson L, Lyu Z, Cameron TA, De Lay NR, Krachler AM, Ling J. Optimal translational fidelity is critical for Salmonella virulence and host interactions. Nucleic Acids Res 2019; 47:5356-5367. [PMID: 30941426 PMCID: PMC6547416 DOI: 10.1093/nar/gkz229] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/19/2019] [Accepted: 03/24/2019] [Indexed: 01/09/2023] Open
Abstract
Translational fidelity is required for accurate flow of genetic information, but is frequently altered by genetic changes and environmental stresses. To date, little is known about how translational fidelity affects the virulence and host interactions of bacterial pathogens. Here we show that surprisingly, either decreasing or increasing translational fidelity impairs the interactions of the enteric pathogen Salmonella Typhimurium with host cells and its fitness in zebrafish. Host interactions are mediated by Salmonella pathogenicity island 1 (SPI-1). Our RNA sequencing and quantitative RT-PCR results demonstrate that SPI-1 genes are among the most down-regulated when translational fidelity is either increased or decreased. Further, this down-regulation of SPI-1 genes depends on the master regulator HilD, and altering translational fidelity destabilizes HilD protein via enhanced degradation by Lon protease. Our work thus reveals that optimal translational fidelity is pivotal for adaptation of Salmonella to the host environment, and provides important mechanistic insights into this process.
Collapse
Affiliation(s)
- Yongqiang Fan
- College of Life and Health Sciences, Northeastern University, Shenyang 110819, People's Republic of China.,Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA.,Shenyang National Laboratory for Materials Science, Northeastern University, Shenyang 110819, People's Republic of China
| | - Laurel Thompson
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Zhihui Lyu
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| | - Todd A Cameron
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Nicholas R De Lay
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Anne Marie Krachler
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Jiqiang Ling
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA.,Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| |
Collapse
|
7
|
Insua I, Petit M, Blackman LD, Keogh R, Pitto‐Barry A, O'Reilly RK, Peacock AFA, Krachler AM, Fernandez‐Trillo F. Structural Determinants of the Stability of Enzyme-Responsive Polyion Complex Nanoparticles Targeting Pseudomonas aeruginosa's Elastase. ChemNanoMat 2018; 4:807-814. [PMID: 30263883 PMCID: PMC6146907 DOI: 10.1002/cnma.201800054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Indexed: 06/08/2023]
Abstract
Here, we report how the stability of polyion complex (PIC) particles containing Pseudomonas aeruginosa's elastase (LasB) degradable peptides and antimicrobial poly(ethylene imine) is significantly improved by careful design of the peptide component. Three LasB-degradable peptides are reported herein, all of them carrying the LasB-degradable sequence -GLA- and for which the number of anionic amino acids and cysteine units per peptide were systematically varied. Our results suggest that while net charge and potential to cross-link via disulfide bond formation do not have a predictable effect on the ability of LasB to degrade these peptides, a significant effect of these two parameters on particle preparation and stability is observed. A range of techniques has been used to characterize these new materials and demonstrates that increasing the charge and cross-linking potential of the peptides results in PIC particles with better stability in physiological conditions and upon storage. These results highlight the importance of molecular design for the preparation of PIC particles and should underpin the future development of these materials for responsive drug delivery.
Collapse
Affiliation(s)
- Ignacio Insua
- School of ChemistryUniversity of BirminghamEdgbastonB15 2TTUK
- Institute of Microbiology and Infection – School of BiosciencesUniversity of BirminghamEdgbastonB15 2TTUK
| | - Marion Petit
- School of ChemistryUniversity of BirminghamEdgbastonB15 2TTUK
| | | | - Robert Keogh
- Department of ChemistryUniversity of WarwickCoventryCV4 7ALUK
| | - Anaïs Pitto‐Barry
- Department of ChemistryUniversity of WarwickCoventryCV4 7ALUK
- Current address: School of Chemistry and BiosciencesUniversity of BradfordBradfordBD7 1DP
| | | | | | - Anne Marie Krachler
- Institute of Microbiology and Infection – School of BiosciencesUniversity of BirminghamEdgbastonB15 2TTUK
- Current address: Department of Microbiology and Molecular GeneticsUniversity of Texas Health Science CenterHouston (TX)USA
| | - Francisco Fernandez‐Trillo
- School of ChemistryUniversity of BirminghamEdgbastonB15 2TTUK
- Institute of Microbiology and Infection – School of BiosciencesUniversity of BirminghamEdgbastonB15 2TTUK
| |
Collapse
|
8
|
Perez-Soto N, Moule L, Crisan DN, Insua I, Taylor-Smith LM, Voelz K, Fernandez-Trillo F, Krachler AM. Correction: Engineering microbial physiology with synthetic polymers: cationic polymers induce biofilm formation in Vibrio choleraeand downregulate the expression of virulence genes. Chem Sci 2018; 9:7715. [PMID: 30393533 PMCID: PMC6187689 DOI: 10.1039/c8sc90189a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 09/19/2018] [Indexed: 11/21/2022] Open
Abstract
Correction for ‘Engineering microbial physiology with synthetic polymers: cationic polymers induce biofilm formation in Vibrio cholerae and downregulate the expression of virulence genes’ by Nicolas Perez-Soto et al., Chem. Sci., 2017, 8, 5291–5298.
Collapse
Affiliation(s)
- Nicolas Perez-Soto
- School of Biosciences
- University of Birmingham
- B15 2TT Birmingham
- UK
- Institute of Microbiology and Infection
| | - Lauren Moule
- School of Biosciences
- University of Birmingham
- B15 2TT Birmingham
- UK
- Institute of Microbiology and Infection
| | - Daniel N. Crisan
- Institute of Microbiology and Infection
- University of Birmingham
- B15 2TT Birmingham
- UK
- School of Chemistry
| | - Ignacio Insua
- Institute of Microbiology and Infection
- University of Birmingham
- B15 2TT Birmingham
- UK
- School of Chemistry
| | - Leanne M. Taylor-Smith
- School of Biosciences
- University of Birmingham
- B15 2TT Birmingham
- UK
- Institute of Microbiology and Infection
| | - Kerstin Voelz
- School of Biosciences
- University of Birmingham
- B15 2TT Birmingham
- UK
- Institute of Microbiology and Infection
| | | | - Anne Marie Krachler
- School of Biosciences
- University of Birmingham
- B15 2TT Birmingham
- UK
- Institute of Microbiology and Infection
| |
Collapse
|
9
|
O’Donoghue EJ, Sirisaengtaksin N, Browning DF, Bielska E, Hadis M, Fernandez-Trillo F, Alderwick L, Jabbari S, Krachler AM. Lipopolysaccharide structure impacts the entry kinetics of bacterial outer membrane vesicles into host cells. PLoS Pathog 2017; 13:e1006760. [PMID: 29186191 PMCID: PMC5724897 DOI: 10.1371/journal.ppat.1006760] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 12/11/2017] [Accepted: 11/17/2017] [Indexed: 11/19/2022] Open
Abstract
Outer membrane vesicles are nano-sized microvesicles shed from the outer membrane of Gram-negative bacteria and play important roles in immune priming and disease pathogenesis. However, our current mechanistic understanding of vesicle-host cell interactions is limited by a lack of methods to study the rapid kinetics of vesicle entry and cargo delivery to host cells. Here, we describe a highly sensitive method to study the kinetics of vesicle entry into host cells in real-time using a genetically encoded, vesicle-targeted probe. We found that the route of vesicular uptake, and thus entry kinetics and efficiency, are shaped by bacterial cell wall composition. The presence of lipopolysaccharide O antigen enables vesicles to bypass clathrin-mediated endocytosis, which enhances both their entry rate and efficiency into host cells. Collectively, our findings highlight the composition of the bacterial cell wall as a major determinant of secretion-independent delivery of virulence factors during Gram-negative infections.
Collapse
Affiliation(s)
- Eloise J. O’Donoghue
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Natalie Sirisaengtaksin
- Department of Microbiology and Molecular Genetics, University of Texas McGovern Medical School at Houston, Houston, Texas, United States of America
| | - Douglas F. Browning
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Ewa Bielska
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Mohammed Hadis
- Institute of Microbiology and Infection, School of Chemistry, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Francisco Fernandez-Trillo
- Institute of Microbiology and Infection, School of Chemistry, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Luke Alderwick
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Sara Jabbari
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- School of Mathematics, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Anne Marie Krachler
- Department of Microbiology and Molecular Genetics, University of Texas McGovern Medical School at Houston, Houston, Texas, United States of America
- * E-mail:
| |
Collapse
|
10
|
Al-Saedi F, Vaz DP, Stones DH, Krachler AM. 3-Sulfogalactosyl-dependent adhesion of Escherichia coli HS multivalent adhesion molecule is attenuated by sulfatase activity. J Biol Chem 2017; 292:19792-19803. [PMID: 28982977 PMCID: PMC5712619 DOI: 10.1074/jbc.m117.817908] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 10/02/2017] [Indexed: 02/06/2023] Open
Abstract
Bacterial adhesion to host receptors is an early and essential step in bacterial colonization, and the nature of adhesin–receptor interactions determines bacterial localization and thus the outcome of these interactions. Here, we determined the host receptors for the multivalent adhesion molecule (MAM) from the gut commensal Escherichia coli HS (MAMHS), which contains an array of seven mammalian cell entry domains. The MAMHS adhesin interacted with a range of host receptors, through recognition of a shared 3-O-sulfogalactosyl moiety. This functional group is also found in mucin, a component of the intestinal mucus layer and thus one of the prime adherence targets for commensal E. coli. Mucin gels impeded the motility of E. coli by acting as a physical barrier, and the barrier effect was enhanced by specific interactions between mucin and MAMHS in a sulfation-dependent manner. Desulfation of mucin by pure sulfatase or the sulfatase-producing commensal Bacteroides thetaiotaomicron decreased binding of E. coli to mucin and increased the attachment of bacteria to the epithelial surface via interactions with surface-localized sulfated lipid and protein receptors. Together, our results demonstrate that the E. coli adhesin MAMHS facilitates retention of a gut commensal by attachment to mucin. They further suggest that the amount of sulfatase secreted by mucin-foraging bacteria such as B. thetaiotaomicron, inhabiting the same niche, may affect the capacity of the mucus barrier to retain commensal E. coli.
Collapse
Affiliation(s)
- Fitua Al-Saedi
- From the Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston B15 2TT Birmingham, United Kingdom and
| | - Diana Pereira Vaz
- From the Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston B15 2TT Birmingham, United Kingdom and.,the Department of Microbiology and Molecular Genetics, University of Texas McGovern Medical School at Houston, Houston, Texas 77030
| | - Daniel H Stones
- From the Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston B15 2TT Birmingham, United Kingdom and
| | - Anne Marie Krachler
- the Department of Microbiology and Molecular Genetics, University of Texas McGovern Medical School at Houston, Houston, Texas 77030
| |
Collapse
|
11
|
Perez-Soto N, Moule L, Crisan DN, Insua I, Taylor-Smith LM, Voelz K, Fernandez-Trillo F, Krachler AM. Engineering microbial physiology with synthetic polymers: cationic polymers induce biofilm formation in Vibrio cholerae and downregulate the expression of virulence genes. Chem Sci 2017; 8:5291-5298. [PMID: 28970909 PMCID: PMC5607900 DOI: 10.1039/c7sc00615b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/10/2017] [Indexed: 12/19/2022] Open
Abstract
Here we report the first application of non-bactericidal synthetic polymers to modulate the physiology of a bacterial pathogen. Poly(N-[3-(dimethylamino)propyl] methacrylamide) (P1) and poly(N-(3-aminopropyl)methacrylamide) (P2), cationic polymers that bind to the surface of V. cholerae, the infectious agent causing cholera disease, can sequester the pathogen into clusters. Upon clustering, V. cholerae transitions to a sessile lifestyle, characterised by increased biofilm production and the repression of key virulence factors such as the cholera toxin (CTX). Moreover, clustering the pathogen results in the minimisation of adherence and toxicity to intestinal epithelial cells. Our results suggest that the reduction in toxicity is associated with the reduction to the number of free bacteria, but also the downregulation of toxin production. Finally we demonstrate that these polymers can reduce colonisation of zebrafish larvae upon ingestion of water contaminated with V. cholerae. Overall, our results suggest that the physiology of this pathogen can be modulated without the need to genetically manipulate the microorganism and that this modulation is an off-target effect that results from the intrinsic ability of the pathogen to sense and adapt to its environment. We believe these findings pave the way towards a better understanding of the interactions between pathogenic bacteria and polymeric materials and will underpin the development of novel antimicrobial polymers.
Collapse
Affiliation(s)
- Nicolas Perez-Soto
- School of Biosciences , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK.,Institute of Microbiology and Infection , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK .
| | - Lauren Moule
- School of Biosciences , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK.,Institute of Microbiology and Infection , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK .
| | - Daniel N Crisan
- Institute of Microbiology and Infection , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK . .,School of Chemistry , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK
| | - Ignacio Insua
- Institute of Microbiology and Infection , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK . .,School of Chemistry , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK
| | - Leanne M Taylor-Smith
- School of Biosciences , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK.,Institute of Microbiology and Infection , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK .
| | - Kerstin Voelz
- School of Biosciences , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK.,Institute of Microbiology and Infection , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK .
| | - Francisco Fernandez-Trillo
- Institute of Microbiology and Infection , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK . .,School of Chemistry , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK
| | - Anne Marie Krachler
- School of Biosciences , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK.,Institute of Microbiology and Infection , University of Birmingham , Edgbaston , B15 2TT Birmingham , UK . .,Department of Microbiology and Molecular Genetics , University of Texas McGovern Medical School at Houston , Houston , TX 77030 , USA .
| |
Collapse
|
12
|
Insua I, Majok S, Peacock AFA, Krachler AM, Fernandez-Trillo F. Preparation and antimicrobial evaluation of polyion complex (PIC) nanoparticles loaded with polymyxin B. Eur Polym J 2017; 87:478-486. [PMID: 28280277 PMCID: PMC5327956 DOI: 10.1016/j.eurpolymj.2016.08.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report the preparation of PIC particles loaded with clinically relevant antibiotic Polymyxin B. PIC particle formulation is optimised to accommodate different loadings of Polymyxin B. PIC particles inhibit the growth of Pseudomonas aeruginosa in a particle dependent manner.
Here, we describe novel polyion complex (PIC) particles for the delivery of Polymyxin B (Pol-B), an antimicrobial peptide currently used in the clinic as a last resort antibiotic against multidrug-resistant gram-negative bacteria. A range of conditions for the controlled assembly of Pol-B with poly(styrene sulphonate) (PSS) has been identified which let us prepare stable colloidal PIC particles. This way, PIC particles containing different Pol-B:PSS ratios have been prepared and their stability under simulated physiological conditions (i.e. pH, osmotic pressure and temperature) characterised. Furthermore, preliminary evaluation of the antimicrobial activity of these Pol-B containing PIC particles has been performed, by monitoring their effect on the growth of Pseudomonas aeruginosa, an opportunistic gram-negative bacterium.
Collapse
Affiliation(s)
- Ignacio Insua
- School of Chemistry, University of Birmingham, B15 2TT Birmingham, UK; Institute of Microbiology and Infection, University of Birmingham, B15 2TT Birmingham, UK
| | - Sieta Majok
- School of Biosciences, University of Birmingham, B15 2TT Birmingham, UK; Institute of Microbiology and Infection, University of Birmingham, B15 2TT Birmingham, UK
| | - Anna F A Peacock
- School of Chemistry, University of Birmingham, B15 2TT Birmingham, UK
| | - Anne Marie Krachler
- School of Biosciences, University of Birmingham, B15 2TT Birmingham, UK; Institute of Microbiology and Infection, University of Birmingham, B15 2TT Birmingham, UK
| | - Francisco Fernandez-Trillo
- School of Chemistry, University of Birmingham, B15 2TT Birmingham, UK; Institute of Microbiology and Infection, University of Birmingham, B15 2TT Birmingham, UK
| |
Collapse
|
13
|
O'Donoghue EJ, Krachler AM. Mechanisms of outer membrane vesicle entry into host cells. Cell Microbiol 2016; 18:1508-1517. [PMID: 27529760 PMCID: PMC5091637 DOI: 10.1111/cmi.12655] [Citation(s) in RCA: 181] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/05/2016] [Accepted: 08/12/2016] [Indexed: 01/18/2023]
Abstract
Bacterial outer membrane vesicles (OMVs) are nano‐sized compartments consisting of a lipid bilayer that encapsulates periplasm‐derived, luminal content. OMVs, which pinch off of Gram‐negative bacteria, are now recognized as a generalized secretion pathway which provides a means to transfer cargo to other bacterial cells as well as eukaryotic cells. Compared with other secretion systems, OMVs can transfer a chemically extremely diverse range of cargo, including small molecules, nucleic acids, proteins, and lipids to proximal cells. Although it is well recognized that OMVs can enter and release cargo inside host cells during infection, the mechanisms of host association and uptake are not well understood. This review highlights existing studies focusing on OMV‐host cell interactions and entry mechanisms, and how these entry routes affect cargo processing within the host. It further compares the wide range of methods currently used to dissect uptake mechanisms, and discusses potential sources of discrepancy regarding the mechanism of OMV uptake across different studies.
Collapse
Affiliation(s)
- Eloise J O'Donoghue
- University of Birmingham, Institute of Microbiology and Infection, School of Biosciences, Edgbaston, Birmingham, B15 2TT, UK
| | - Anne Marie Krachler
- University of Birmingham, Institute of Microbiology and Infection, School of Biosciences, Edgbaston, Birmingham, B15 2TT, UK.
| |
Collapse
|
14
|
Patel S, Krachler AM. Sexual Health-Get Involved: A Kinesthetic Learning Experience of STI Transmission and Prevention. J Microbiol Biol Educ 2016; 17:302-304. [PMID: 27158319 PMCID: PMC4858374 DOI: 10.1128/jmbe.v17i2.1091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OFSTED repeatedly finds the teaching of sexually transmitted infections in secondary schools ‘inadequate’ across the UK (3). This is thought to be due to a number of reasons, including the fact that staff teaching this topic feel inadequately prepared and not knowledgeable enough to do so (4).
In 2010, over half of newly diagnosed sexually transmitted infections (STIs) in England were within patients aged 16-24 years (2). This could be the result of a lack of mandatory, quality sexual health education in schools, combined with larger scale social issues. Young females, in particular, reported feelings of shame when visiting sexual health clinics which on occasion may compel them to lie about their sexual history to a practitioner in order to protect a ‘fragile sexual reputation’(1).
In response to the recommendations of FPA and the aforementioned public health statistics, this session was developed to improve student understanding of sexual health and of the risks associated with different sexual behaviors. Another aim was, by integrating information about the importance of regular sexual health check-ups into sexual health education in schools, to reduce the associated feelings of shame across the young female population. The activity was carried out with two classes of Year 12 students (16-17 years) in an independent school in the London borough of Lewisham. The session builds on education about STIs, which is part of the national science curriculum, and extends concepts about transmission to the most common STIs prevalent within the population aged 16-24.
Collapse
Affiliation(s)
| | - Anne Marie Krachler
- Corresponding author. Mailing address: Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK. Phone: +44(0)121 414 7417. E-mail:
| |
Collapse
|
15
|
Affiliation(s)
- Anne Marie Krachler
- a Institute of Microbiology and Infection, School of Biosciences, University of Birmingham , Birmingham , UK
| |
Collapse
|
16
|
Insua I, Liamas E, Zhang Z, Peacock AFA, Krachler AM, Fernandez-Trillo F. Enzyme-responsive polyion complex (PIC) nanoparticles for the targeted delivery of antimicrobial polymers. Polym Chem 2016; 7:2684-2690. [PMID: 27148427 PMCID: PMC4841106 DOI: 10.1039/c6py00146g] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/13/2016] [Indexed: 12/30/2022]
Abstract
Here we present new enzyme-responsive polyion complex (PIC) nanoparticles prepared from antimicrobial poly(ethylene imine) and an anionic enzyme-responsive peptide targeting Pseudomonas aeruginosa's elastase.
Here we present new enzyme-responsive polyion complex (PIC) nanoparticles prepared from antimicrobial poly(ethylene imine) and an anionic enzyme-responsive peptide targeting Pseudomonas aeruginosa's elastase. The synthetic conditions used to prepare these nanomaterials allowed us to optimise particle size and charge, and their stability under physiological conditions. We demonstrate that these enzyme responsive PIC nanoparticles are selectively degraded in the presence of P. aeruginosa elastase without being affected by other endogenous elastases. This enzyme-responsive PIC particle can exert an elastase-specific antimicrobial effect against P. aeruginosa without affecting non-pathogenic strains of these bacteria. These targeted enzyme-responsive PIC nanoparticles constitute a novel platform for the delivery of antimicrobial peptides and polymers, and can be a powerful tool in the current race against antimicrobial resistance.
Collapse
Affiliation(s)
- Ignacio Insua
- School of Chemistry , University of Birmingham , B15 2TT Birmingham , UK
| | - Evangelos Liamas
- School of Chemical Engineering , University of Birmingham , B15 2TT Birmingham , UK
| | - Zhenyu Zhang
- School of Chemical Engineering , University of Birmingham , B15 2TT Birmingham , UK
| | - Anna F A Peacock
- School of Chemistry , University of Birmingham , B15 2TT Birmingham , UK
| | - Anne Marie Krachler
- School of Biosciences , University of Birmingham , B15 2TT Birmingham , UK ; Institute of Microbiology and Infection , University of Birmingham , B15 2TT Birmingham , UK .
| | - Francisco Fernandez-Trillo
- School of Chemistry , University of Birmingham , B15 2TT Birmingham , UK ; Institute of Microbiology and Infection , University of Birmingham , B15 2TT Birmingham , UK .
| |
Collapse
|
17
|
Abstract
Enterohemorrhagic Escherichia coli O157:H7 is a food-borne pathogen transmitted via the fecal-oral route, and can cause bloody diarrhea and hemolytic uremic syndrome (HUS) in the human host. Although a range of colonization factors, Shiga toxins and a type III secretion system (T3SS) all contribute to disease development, the locus of enterocyte effacement (LEE) encoded T3SS is responsible for the formation of lesions in the intestinal tract. While a variety of chemical cues in the host environment are known to up-regulate LEE expression, we recently demonstrated that changes in physical forces at the site of attachment are required for localized, full induction of the system and thus spatial regulation of virulence in the intestinal tract. Here, we discuss our findings in the light of other recent studies describing mechanosensing of the host and force-dependent induction of virulence mechanisms. We discuss potential mechanisms of mechanosensing and mechanotransduction, and the level of conservation across bacterial species.
Collapse
Affiliation(s)
- Md. Shahidul Islam
- Department of Biotechnology, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Anne Marie Krachler
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| |
Collapse
|
18
|
Collins R, Krachler AM. There's More to Science than Research: A Team-Based Role Game to Develop School Students' Understanding of Science Careers in Pharmaceutical Quality Control. J Microbiol Biol Educ 2015; 16:263-265. [PMID: 26753038 PMCID: PMC4690572 DOI: 10.1128/jmbe.v16i2.917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
School students lack information about STEM based careers, a subject that is not sufficiently embedded in the national science curriculum. As a result, students feel they receive insufficient advice to support their choice of subjects at GCSE level and beyond. Students struggle to envisage potential career pathways leading on from studying science at school, and especially for younger students it is difficult to convey typical science-based career pictures in a way that is easily accessible to them. To address this need, we developed an interactive team-based activity which uses role play to help students envisage typical work processes within a science-based career—microbial quality control in a pharmaceutical industrial environment. This activity addresses children’s curiosity about science-based careers, by enabling them to experience typical every day work processes in an industrial environment in a hands-on fashion. Additionally, the activity helps to convey abstract concepts, such as the abundance of microbes in the natural environment, microbial contamination and the importance of hygiene, which link to the science curriculum.
Collapse
Affiliation(s)
| | - Anne Marie Krachler
- Corresponding author. Mailing address: Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK. Phone: +44(0)121 4147417. E-mail:
| |
Collapse
|
19
|
Mahmoud RY, Stones DH, Li W, Emara M, El-Domany RA, Wang D, Wang Y, Krachler AM, Yu J. The Multivalent Adhesion Molecule SSO1327 plays a key role in Shigella sonnei pathogenesis. Mol Microbiol 2015; 99:658-73. [PMID: 26481305 DOI: 10.1111/mmi.13255] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2015] [Indexed: 12/30/2022]
Abstract
Shigella sonnei is a bacterial pathogen and causative agent of bacillary dysentery. It deploys a type III secretion system to inject effector proteins into host epithelial cells and macrophages, an essential step for tissue invasion and immune evasion. Although the arsenal of bacterial effectors and their cellular targets have been studied extensively, little is known about the prerequisites for deployment of type III secreted proteins during infection. Here, we describe a novel S. sonnei adhesin, SSO1327 which is a multivalent adhesion molecule (MAM) required for invasion of epithelial cells and macrophages and for infection in vivo. The S. sonnei MAM mediates intimate attachment to host cells, which is required for efficient translocation of type III effectors into host cells. SSO1327 is non-redundant to IcsA; its activity is independent of type III secretion. In contrast to the up-regulation of IcsA-dependent and independent attachment and invasion by deoxycholate in Shigella flexneri, deoxycholate negatively regulates IcsA and MAM in S. sonnei resulting in reduction in attachment and invasion and virulence attenuation in vivo. A strain deficient for SSO1327 is avirulent in vivo, but still elicits a host immune response.
Collapse
Affiliation(s)
- Rasha Y Mahmoud
- Strathclyde Institute of Pharmacy and Biomedical Sciences (SIPBS), University of Strathclyde, Glasgow, UK.,Department of Microbiology and Immunology, Faculty of Pharmacy, Helwan University, Cairo, Egypt
| | - Daniel Henry Stones
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Wenqin Li
- Strathclyde Institute of Pharmacy and Biomedical Sciences (SIPBS), University of Strathclyde, Glasgow, UK
| | - Mohamed Emara
- Department of Microbiology and Immunology, Faculty of Pharmacy, Helwan University, Cairo, Egypt
| | - Ramadan A El-Domany
- Department of Microbiology and Immunology, Faculty of Pharmacy, Helwan University, Cairo, Egypt
| | - Depu Wang
- The center of Translational Medicine, The First Affiliated Hospital, Xi'an Jiao Tong University, Xi'an, China
| | - Yili Wang
- Institute for Cancer Research, School of Basic Medical Science, Health Science Center, Xi'an Jiao Tong University, Xi'an, China
| | - Anne Marie Krachler
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Jun Yu
- Strathclyde Institute of Pharmacy and Biomedical Sciences (SIPBS), University of Strathclyde, Glasgow, UK
| |
Collapse
|
20
|
Abstract
Bacterial pathogens often target conserved cellular mechanisms within their hosts to rewire signaling pathways and facilitate infection. Rho GTPases are important nodes within eukaryotic signaling networks and thus constitute a common target of pathogen-mediated manipulation. A diverse array of microbial mechanisms exists to interfere with Rho GTPase signaling. While targeting of GTPases by secreted bacterial effectors is a well-known strategy bacterial pathogens employ to interfere with the host, we have recently described pathogen adhesion as a novel extracellular stimulus that hijacks host GTPase signaling. The Multivalent Adhesion Molecule MAM7 from Vibrio parahaemolyticus directly binds host cell membrane lipids. The ensuing coalescence of phosphatidic acid ligands in the host membrane leads to downstream activation of RhoA and actin rearrangements. Herein, we discuss mechanistic models of lipid-mediated Rho activation and the implications from the infected host's and the pathogen's perspective.
Collapse
Affiliation(s)
- Daniel Henry Stones
- a Institute of Microbiology and Infection ; School of Biosciences ; University of Birmingham ; Edgbaston, Birmingham , United Kingdom
| | | |
Collapse
|
21
|
Lim J, Stones DH, Hawley CA, Watson CA, Krachler AM. Multivalent adhesion molecule 7 clusters act as signaling platform for host cellular GTPase activation and facilitate epithelial barrier dysfunction. PLoS Pathog 2014; 10:e1004421. [PMID: 25255250 PMCID: PMC4177989 DOI: 10.1371/journal.ppat.1004421] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 08/25/2014] [Indexed: 01/24/2023] Open
Abstract
Vibrio parahaemolyticus is an emerging bacterial pathogen which colonizes the gastrointestinal tract and can cause severe enteritis and bacteraemia. During infection, V. parahaemolyticus primarily attaches to the small intestine, where it causes extensive tissue damage and compromises epithelial barrier integrity. We have previously described that Multivalent Adhesion Molecule (MAM) 7 contributes to initial attachment of V. parahaemolyticus to epithelial cells. Here we show that the bacterial adhesin, through multivalent interactions between surface-induced adhesin clusters and phosphatidic acid lipids in the host cell membrane, induces activation of the small GTPase RhoA and actin rearrangements in host cells. In infection studies with V. parahaemolyticus we further demonstrate that adhesin-triggered activation of the ROCK/LIMK signaling axis is sufficient to redistribute tight junction proteins, leading to a loss of epithelial barrier function. Taken together, these findings show an unprecedented mechanism by which an adhesin acts as assembly platform for a host cellular signaling pathway, which ultimately facilitates breaching of the epithelial barrier by a bacterial pathogen. Vibrio parahaemolyticus is a bacterial pathogen which occurs in marine and estuarine environments. It is a main cause of gastrointestinal illness following the consumption of raw or undercooked seafood. In immunocompromised people, the bacteria can sometimes enter the bloodstream and cause septicemia, a serious and often fatal condition. V. parahaemolyticus attaches to host tissues using adhesive proteins. Multivalent Adhesion Molecule (MAM) 7 is an adhesin which helps the bacteria to hold onto the host cells early on during infection. It does so by binding two different molecules on the host, a protein (fibronectin) and phospholipids called phosphatidic acids. We show that MAM7 does not only play a role in sticking to host cells. By forming adhesin clusters on the host surface and binding to host lipids, it triggers signaling processes in the host. These include activation of RhoA, an important mediator of cytoskeletal dynamics. By doing so, MAM7 perturbs proteins at cellular junctions, which normally maintain the cells in the gut as a tightly sealed layer protective of environmental influences. When bacteria use MAM7 to attach to the intestine, the seals between cells break, permitting bacteria to cross the barrier and cause infection of underlying tissues.
Collapse
Affiliation(s)
- Jenson Lim
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Daniel H. Stones
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Catherine Alice Hawley
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Charlie Anne Watson
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Anne Marie Krachler
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- * E-mail:
| |
Collapse
|
22
|
Abstract
Bacterial infections are a major cause of morbidity and mortality worldwide and are increasingly problematic to treat due to the rise in antibiotic-resistant strains. It becomes more and more challenging to develop new antimicrobials that are able to withstand the ever-increasing repertoire of bacterial resistance mechanisms. This necessitates the development of alternative approaches to prevent and treat bacterial infections. One of the first steps during bacterial infection is adhesion of the pathogen to host cells. A pathogen’s ability to colonize and invade host tissues strictly depends on this process. Thus, interference with adhesion (anti-adhesion therapy) is an efficient way to prevent or treat bacterial infections. As a basis to present different strategies to interfere with pathogen adhesion, this review briefly introduces general concepts of bacterial attachment to host cells. We further discuss advantages and disadvantages of anti-adhesion treatments and issues that are in need of improvement so as to make anti-adhesion compounds a more broadly applicable alternative to conventional antimicrobials.
Collapse
Affiliation(s)
- Anne Marie Krachler
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | | |
Collapse
|
23
|
Hawley CA, Watson CA, Orth K, Krachler AM. A MAM7 peptide-based inhibitor of Staphylococcus aureus adhesion does not interfere with in vitro host cell function. PLoS One 2013; 8:e81216. [PMID: 24265842 PMCID: PMC3827224 DOI: 10.1371/journal.pone.0081216] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 10/09/2013] [Indexed: 11/18/2022] Open
Abstract
Adhesion inhibitors that block the attachment of pathogens to host tissues may be used synergistically with or as an alternative to antibiotics. The wide-spread bacterial adhesin Multivalent Adhesion Molecule (MAM) 7 has recently emerged as a candidate molecule for a broad-spectrum adhesion inhibitor which may be used to prevent bacterial colonization of wounds. Here we have tested if the antibacterial properties of a MAM-based inhibitor could be used to competitively inhibit adhesion of methicillin-resistant Staphylococcus aureus (MRSA) to host cells. Additionally, we analyzed its effect on host cellular functions linked to the host receptor fibronectin, such as migration, adhesion and matrix formation in vitro, to evaluate potential side effects prior to advancing our studies to in vivo infection models. As controls, we used inhibitors based on well-characterized bacterial adhesin-derived peptides from F1 and FnBPA, which are known to affect host cellular functions. Inhibitors based on F1 or FnBPA blocked MRSA attachment but at the same time abrogated important cellular functions. A MAM7-based inhibitor did not interfere with host cell function while showing good efficacy against MRSA adhesion in a tissue culture model. These observations provide a possible candidate for a bacterial adhesion inhibitor that does not cause adverse effects on host cells while preventing bacterial infection.
Collapse
Affiliation(s)
- Catherine Alice Hawley
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Charlie Anne Watson
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Kim Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Anne Marie Krachler
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
- * E-mail:
| |
Collapse
|
24
|
Krachler AM, Mende K, Murray C, Orth K. In vitro characterization of multivalent adhesion molecule 7-based inhibition of multidrug-resistant bacteria isolated from wounded military personnel. Virulence 2012; 3:389-99. [PMID: 22722243 DOI: 10.4161/viru.20816] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Treatment of wounded military personnel at military medical centers is often complicated by colonization and infection of wounds with pathogenic bacteria. These include nosocomially transmitted, often multidrug-resistant pathogens such as Acinetobacter baumannii-calcoaceticus complex, Pseudomonas aeruginosa and extended spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae. We analyzed the efficacy of multivalent adhesion molecule (MAM) 7-based anti-adhesion treatment of host cells against aforementioned pathogens in a tissue culture infection model. Herein, we observed that a correlation between two important hallmarks of virulence, attachment and cytotoxicity, could serve as a useful predictor for the success of MAM7-based inhibition against bacterial infections. Initially, we characterized 20 patient isolates (five from each pathogen mentioned above) in terms of genotypic diversity, antimicrobial susceptibility and important hallmarks of pathogenicity (biofilm formation, attachment to and cytotoxicity toward cultured host cells). All isolates displayed a high degree of genotypic diversity, which was also reflected by large strain-to-strain variability in terms of biofilm formation, attachment and cytotoxicity within each group of pathogen. Using non-pathogenic bacteria expressing MAM7 or latex beads coated with recombinant MAM7 for anti-adhesion treatment, we showed a decrease in cytotoxicity, indicating that MAM7 has potential as a prophylactic agent to attenuate infection by multidrug-resistant bacterial pathogens.
Collapse
Affiliation(s)
- Anne Marie Krachler
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | | | | | | |
Collapse
|
25
|
Zhang L, Krachler AM, Broberg CA, Li Y, Mirzaei H, Gilpin CJ, Orth K. Type III effector VopC mediates invasion for Vibrio species. Cell Rep 2012; 1:453-60. [PMID: 22787576 DOI: 10.1016/j.celrep.2012.04.004] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 03/26/2012] [Accepted: 04/17/2012] [Indexed: 11/30/2022] Open
Abstract
Vibrio spp. are associated with infections caused by contaminated food and water. A type III secretion system (T3SS2) is a shared feature of all clinical isolates of V. parahaemolyticus and some V. cholerae strains. Despite its being responsible for enterotoxicity, no molecular mechanism has been determined for the T3SS2-dependent pathogenicity. Here, we show that although Vibrio spp. are typically thought of as extracellular pathogens, the T3SS2 of Vibrio mediates host cell invasion, vacuole formation, and replication of intracellular bacteria. The catalytically active effector VopC is critical for Vibrio T3SS2-mediated invasion. There are other marine bacteria encoding VopC homologs associated with a T3SS; therefore, we predict that these bacteria are also likely to use T3SS-mediated invasion as part of their pathogenesis mechanisms. These findings suggest a new molecular paradigm for Vibrio pathogenicity and modify our view of the roles of T3SS effectors that are translocated during infection.
Collapse
Affiliation(s)
- Lingling Zhang
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | | | | | | | | | | | | |
Collapse
|
26
|
Abstract
Pathogen attachment to host tissues is one of the initial and most crucial events during the establishment of bacterial infections and thus interference with this step could be an efficient strategy to fight bacterial colonization. Our recent work has identified one of the factors involved in initial binding of host cells by a wide range of Gram-negative pathogens, Multivalent Adhesion Molecule (MAM) 7. Interference with MAM7-mediated attachment, for example by pre-incubation of host cells with recombinant MAM7, significantly delays the onset of hallmarks of infection, such as pathogen-mediated cytotoxicity or the development of other adhesive structures such as actin pedestals. Thus, we are trying to develop tools based on MAM7 that can be used to prevent or diminish certain Gram-negative bacterial infections. Herein, we describe the use of bead-coupled MAM7 as an inhibitor of infection with the clinically relevant pathogen Pseudomonas aeruginosa.
Collapse
Affiliation(s)
- Anne Marie Krachler
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | | | | |
Collapse
|
27
|
Abstract
Bacterial pathogens use effector proteins to manipulate their hosts to propagate infection. These effectors divert host cell signaling pathways to the benefit of the pathogen and frequently target kinase signaling cascades. Notable pathways that are usurped include the nuclear factor κB (NF-κB), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/Akt, and p21-activated kinase (PAK) pathways. Analyzing the functions of pathogenic effectors and their intersection with host kinase pathways has provided interesting insights into both the mechanisms of virulence and eukaryotic signaling.
Collapse
Affiliation(s)
- Anne Marie Krachler
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | | | | |
Collapse
|
28
|
Krachler AM, Orth K. Functional characterization of the interaction between bacterial adhesin multivalent adhesion molecule 7 (MAM7) protein and its host cell ligands. J Biol Chem 2011; 286:38939-47. [PMID: 21937438 DOI: 10.1074/jbc.m111.291377] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The ability of a pathogen to rapidly form a stable interaction with the host cell surface is key to its success. Bacterial pathogens use a repertoire of virulence factors, but their efficient use relies on close contact between the host and the pathogen. We have recently identified a constitutively expressed MAM7 (multivalent adhesion molecule 7), which is widely distributed in gram-negative pathogens and enables them to establish initial contact with the host cell. Here, we describe the dissection of the MAM7 interaction with the host cell surface into two distinct binding events, involving the host protein fibronectin and the membrane phospholipid phosphatidic acid. We analyzed which domains within MAM7 and fibronectin are necessary for complex formation. We further studied phosphatidic acid binding by MAM7 using site-directed mutagenesis and liposome association assays and demonstrated that a specific distribution of basic charge on MAM7 is required for high affinity binding. Finally, we showed that fibronectin and phosphatidic acid binding to MAM7 are not mutually exclusive and that the three molecules likely assemble into a tripartite complex on the host cell surface.
Collapse
Affiliation(s)
- Anne Marie Krachler
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | | |
Collapse
|
29
|
Abstract
The tetratricopeptide repeat (TPR) motif is a protein-protein interaction module that acts as an organizing centre for complexes regulating a multitude of biological processes. Despite accumulating evidence for the formation of TPR oligomers as an additional level of regulation there is a lack of structural and solution data explaining TPR self-association. In the present work we characterize the trimeric TPR-containing protein YbgF, which is linked to the Tol system in Gram-negative bacteria. By subtracting previously identified TPR consensus residues required for stability of the fold from residues conserved across YbgF homologs, we identified residues involved in oligomerization of the C-terminal YbgF TPR domain. Crafting these residues, which are located in loop regions between TPR motifs, onto the monomeric consensus TPR protein CTPR3 induced the formation of oligomers. The crystal structure of this engineered oligomer shows an asymmetric trimer where stacking interactions between the introduced tyrosines and displacement of the C-terminal hydrophilic capping helix, present in most TPR domains, are key to oligomerization. Asymmetric trimerization of the YbgF TPR domain and CTPR3Y3 leads to the formation of higher order oligomers both in the crystal and in solution. However, such open-ended self-association does not occur in full-length YbgF suggesting that the protein's N-terminal coiled-coil domain restricts further oligomerization. This interpretation is borne out in experiments where the coiled-coil domain of YbgF was engineered onto the N-terminus of CTPR3Y3 and shown to block self-association beyond trimerization. Our study lays the foundations for understanding the structural basis for TPR domain self-association and how such self-association can be regulated in TPR domain-containing proteins.
Collapse
Affiliation(s)
- Anne Marie Krachler
- Department of Biology, University of York, Heslington, York YO10 5YW, United Kingdom
| | | | | |
Collapse
|
30
|
Krachler AM, Sharma A, Cauldwell A, Papadakos G, Kleanthous C. TolA modulates the oligomeric status of YbgF in the bacterial periplasm. J Mol Biol 2010; 403:270-85. [PMID: 20816983 DOI: 10.1016/j.jmb.2010.08.050] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 08/18/2010] [Accepted: 08/26/2010] [Indexed: 10/19/2022]
Abstract
The trans-envelope Tol complex of Gram-negative bacteria is recruited to the septation apparatus during cell division where it is involved in stabilizing the outer membrane. The last gene in the tol operon, ybgF, is highly conserved, yet does not seem to be required for Tol function. We have addressed this anomaly by characterizing YbgF from Escherichia coli and its interaction with TolA, which, based on previous yeast two-hybrid data, is the only known physical link between YbgF and the Tol system. We show that the stable YbgF trimer undergoes a marked change in oligomeric state on binding TolA, forming a one-to-one complex with the Tol protein. Through a combination of pull-down assays, deletion analysis, and isothermal titration calorimetry, we map the TolA-YbgF interface to the C-terminal tetratricopeptide repeat domain of YbgF and 31 residues at the C-terminal end of TolA domain II (TolA(280-313)). We show that TolB, which binds TolA domain III close to the YbgF binding site, has no impact on the YbgF-TolA association. We also report the crystal structures of the two component domains of YbgF, the N-terminal coiled coil from E. coli YbgF, which forms a stable trimer and controls the oligomeric status of YbgF, and the monomeric tetratricopeptide repeat domain from Xanthomonas campestris YbgF, which is also able to trimerize. Although the coiled coil is not directly involved in TolA binding, we demonstrate that the regular hydrophilic patterning of its otherwise hydrophobic core is a prerequisite for the TolA-induced oligomeric-state transition of YbgF. We postulate that rather than YbgF affecting Tol function, it is the change in YbgF oligomeric status (with an accompanying change in its function) that likely explains the necessity for tight co-regulation of the ybgF and tol genes in Gram-negative bacteria.
Collapse
Affiliation(s)
- Anne Marie Krachler
- Department of Biology, University of York, Heslington, PO Box 373, York YO10 5YW, UK
| | | | | | | | | |
Collapse
|
31
|
Bonsor DA, Hecht O, Vankemmelbeke M, Sharma A, Krachler AM, Housden NG, Lilly KJ, James R, Moore GR, Kleanthous C. Allosteric β-propeller signalling in TolB and its manipulation by translocating colicins. EMBO J 2009. [DOI: 10.1038/emboj.2009.266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|
32
|
Bonsor DA, Hecht O, Vankemmelbeke M, Sharma A, Krachler AM, Housden NG, Lilly KJ, James R, Moore GR, Kleanthous C. Allosteric beta-propeller signalling in TolB and its manipulation by translocating colicins. EMBO J 2009; 28:2846-57. [PMID: 19696740 PMCID: PMC2750012 DOI: 10.1038/emboj.2009.224] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Accepted: 07/13/2009] [Indexed: 01/09/2023] Open
Abstract
The Tol system is a five-protein assembly parasitized by colicins and bacteriophages that helps stabilize the Gram-negative outer membrane (OM). We show that allosteric signalling through the six-bladed beta-propeller protein TolB is central to Tol function in Escherichia coli and that this is subverted by colicins such as ColE9 to initiate their OM translocation. Protein-protein interactions with the TolB beta-propeller govern two conformational states that are adopted by the distal N-terminal 12 residues of TolB that bind TolA in the inner membrane. ColE9 promotes disorder of this 'TolA box' and recruitment of TolA. In contrast to ColE9, binding of the OM lipoprotein Pal to the same site induces conformational changes that sequester the TolA box to the TolB surface in which it exhibits little or no TolA binding. Our data suggest that Pal is an OFF switch for the Tol assembly, whereas colicins promote an ON state even though mimicking Pal. Comparison of the TolB mechanism to that of vertebrate guanine nucleotide exchange factor RCC1 suggests that allosteric signalling may be more prevalent in beta-propeller proteins than currently realized.
Collapse
Affiliation(s)
| | - Oliver Hecht
- Centre for Molecular and Structural Biochemistry, School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, UK
| | - Mireille Vankemmelbeke
- School of Molecular Medical Sciences, Institute of Infection, Inflammation and Immunity, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, UK
| | - Amit Sharma
- Department of Biology, University of York, York, UK
| | | | | | | | - Richard James
- School of Molecular Medical Sciences, Institute of Infection, Inflammation and Immunity, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, UK
| | - Geoffrey R Moore
- Centre for Molecular and Structural Biochemistry, School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, UK
| | - Colin Kleanthous
- Department of Biology, University of York, York, UK,Department of Biology (Area 10), University of York, Heslington, PO Box 373, York, YO10 5YW, UK. Tel.: +44 0 1904 328820; Fax: +44 0 1904 328825; E-mail:
| |
Collapse
|