1
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Tijoriwalla S, Liyanage T, Herath TUB, Lee N, Rehman A, Gianfelice A, Ireton K. The host GTPase Dynamin 2 modulates apical junction structure to control cell-to-cell spread of Listeria monocytogenes. Infect Immun 2024; 92:e0013624. [PMID: 39133017 DOI: 10.1128/iai.00136-24] [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: 04/08/2024] [Accepted: 07/16/2024] [Indexed: 08/13/2024] Open
Abstract
The food-borne pathogen Listeria monocytogenes uses actin-based motility to generate plasma membrane protrusions that mediate the spread of bacteria between host cells. In polarized epithelial cells, efficient protrusion formation by L. monocytogenes requires the secreted bacterial protein InlC, which binds to a carboxyl-terminal Src homology 3 (SH3) domain in the human scaffolding protein Tuba. This interaction antagonizes Tuba, thereby diminishing cortical tension at the apical junctional complex and enhancing L. monocytogenes protrusion formation and spread. Tuba contains five SH3 domains apart from the domain that interacts with InlC. Here, we show that human GTPase Dynamin 2 associates with two SH3 domains in the amino-terminus of Tuba and acts together with this scaffolding protein to control the spread of L. monocytogenes. Genetic or pharmacological inhibition of Dynamin 2 or knockdown of Tuba each restored normal protrusion formation and spread to a bacterial strain deleted for the inlC gene (∆inlC). Dynamin 2 localized to apical junctions in uninfected human cells and protrusions in cells infected with L. monocytogenes. Localization of Dynamin 2 to junctions and protrusions depended on Tuba. Knockdown of Dynamin 2 or Tuba diminished junctional linearity, indicating a role for these proteins in controlling cortical tension. Infection with L. monocytogenes induced InlC-dependent displacement of Dynamin 2 from junctions, suggesting a possible mechanism of antagonism of this GTPase. Collectively, our results show that Dynamin 2 cooperates with Tuba to promote intercellular tension that restricts the spread of ∆inlC Listeria. By expressing InlC, wild-type L. monocytogenes overcomes this restriction.
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Affiliation(s)
- Serena Tijoriwalla
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Thiloma Liyanage
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Thilina U B Herath
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Nicole Lee
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Attika Rehman
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Antonella Gianfelice
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Keith Ireton
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
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2
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Raab JE, Hamilton DJ, Harju TB, Huynh TN, Russo BC. Pushing boundaries: mechanisms enabling bacterial pathogens to spread between cells. Infect Immun 2024; 92:e0052423. [PMID: 38661369 PMCID: PMC11385730 DOI: 10.1128/iai.00524-23] [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] [Indexed: 04/26/2024] Open
Abstract
For multiple intracellular bacterial pathogens, the ability to spread directly into adjacent epithelial cells is an essential step for disease in humans. For pathogens such as Shigella, Listeria, Rickettsia, and Burkholderia, this intercellular movement frequently requires the pathogens to manipulate the host actin cytoskeleton and deform the plasma membrane into structures known as protrusions, which extend into neighboring cells. The protrusion is then typically resolved into a double-membrane vacuole (DMV) from which the pathogen quickly escapes into the cytosol, where additional rounds of intercellular spread occur. Significant progress over the last few years has begun to define the mechanisms by which intracellular bacterial pathogens spread. This review highlights the interactions of bacterial and host factors that drive mechanisms required for intercellular spread with a focus on how protrusion structures form and resolve.
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Affiliation(s)
- Julie E Raab
- Department of Immunology and Microbiology, School of Medicine, University of Colorado-Anschutz Medical Campus, Denver, Colorado, USA
| | - Desmond J Hamilton
- Department of Immunology and Microbiology, School of Medicine, University of Colorado-Anschutz Medical Campus, Denver, Colorado, USA
| | - Tucker B Harju
- Department of Immunology and Microbiology, School of Medicine, University of Colorado-Anschutz Medical Campus, Denver, Colorado, USA
| | - Thao N Huynh
- Department of Immunology and Microbiology, School of Medicine, University of Colorado-Anschutz Medical Campus, Denver, Colorado, USA
| | - Brian C Russo
- Department of Immunology and Microbiology, School of Medicine, University of Colorado-Anschutz Medical Campus, Denver, Colorado, USA
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3
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McGinn J, Wen A, Edwards DL, Brinkley DM, Lamason RL. An expanded genetic toolkit for inducible expression and targeted gene silencing in Rickettsia parkeri. J Bacteriol 2024; 206:e0009124. [PMID: 38842342 PMCID: PMC11270864 DOI: 10.1128/jb.00091-24] [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: 03/14/2024] [Accepted: 05/14/2024] [Indexed: 06/07/2024] Open
Abstract
Pathogenic species within the Rickettsia genus are transmitted to humans through arthropod vectors and cause a spectrum of diseases ranging from mild to life-threatening. Despite rickettsiae posing an emerging global health risk, the genetic requirements of their infectious life cycles remain poorly understood. A major hurdle toward building this understanding has been the lack of efficient tools for genetic manipulation, owing to the technical difficulties associated with their obligate intracellular nature. To this end, we implemented the Tet-On system to enable conditional gene expression in Rickettsia parkeri. Using Tet-On, we show inducible expression of antibiotic resistance and a fluorescent reporter. We further used this inducible promoter to screen the ability of R. parkeri to express four variants of the catalytically dead Cas9 (dCas9). We demonstrate that all four dCas9 variants can be expressed in R. parkeri and used for CRISPR interference (CRISPRi)-mediated targeted gene knockdown. We show targeted knockdown of an antibiotic resistance gene as well as the endogenous virulence factor sca2. Altogether, we have developed systems for inducible gene expression and CRISPRi-mediated gene knockdown for the first time in rickettsiae, laying the groundwork for more scalable, targeted mechanistic investigations into their infectious life cycles.IMPORTANCEThe spotted fever group of Rickettsia contains vector-borne pathogenic bacteria that are neglected and emerging threats to public health. Due to the obligate intracellular nature of rickettsiae, the development of tools for genetic manipulation has been stunted, and the molecular and genetic underpinnings of their infectious lifecycle remain poorly understood. Here, we expand the genetic toolkit by introducing systems for conditional gene expression and CRISPR interference (CRISPRi)-mediated gene knockdown. These systems allow for relatively easy manipulation of rickettsial gene expression. We demonstrate the effectiveness of these tools by disrupting the intracellular life cycle using CRISPRi to deplete the sca2 virulence factor. These tools will be crucial for building a more comprehensive and detailed understanding of rickettsial biology and pathogenesis.
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Affiliation(s)
- Jon McGinn
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Annie Wen
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Desmond L. Edwards
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - David M. Brinkley
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Rebecca L. Lamason
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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4
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Sanderlin AG, Kurka Margolis H, Meyer AF, Lamason RL. Cell-selective proteomics reveal novel effectors secreted by an obligate intracellular bacterial pathogen. Nat Commun 2024; 15:6073. [PMID: 39025857 PMCID: PMC11258249 DOI: 10.1038/s41467-024-50493-9] [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: 11/27/2023] [Accepted: 07/11/2024] [Indexed: 07/20/2024] Open
Abstract
Pathogenic bacteria secrete protein effectors to hijack host machinery and remodel their infectious niche. Rickettsia spp. are obligate intracellular bacteria that can cause life-threatening disease, but their absolute dependence on the host cell has impeded discovery of rickettsial effectors and their host targets. We implemented bioorthogonal non-canonical amino acid tagging (BONCAT) during R. parkeri infection to selectively label, isolate, and identify effectors delivered into the host cell. As the first use of BONCAT in an obligate intracellular bacterium, our screen more than doubles the number of experimentally validated effectors for the genus. The seven novel secreted rickettsial factors (Srfs) we identified include Rickettsia-specific proteins of unknown function that localize to the host cytoplasm, mitochondria, and ER. We further show that one such effector, SrfD, interacts with the host Sec61 translocon. Altogether, our work uncovers a diverse set of previously uncharacterized rickettsial effectors and lays the foundation for a deeper exploration of the host-pathogen interface.
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Affiliation(s)
- Allen G Sanderlin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Abigail F Meyer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Rebecca L Lamason
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
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5
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Vondrak CJ, Sit B, Suwanbongkot C, Macaluso KR, Lamason RL. A conserved interaction between the effector Sca4 and host endocytic machinery suggests additional roles for Sca4 during rickettsial infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.24.600492. [PMID: 38979345 PMCID: PMC11230260 DOI: 10.1101/2024.06.24.600492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Intracellular bacterial pathogens deploy secreted effector proteins that manipulate diverse host machinery and pathways to promote infection. Although many effectors carry out a single specific function or interaction, there are a growing number of secreted pathogen effectors capable of interacting with multiple host factors. However, few effectors secreted by obligate intracellular Rickettsia species have been linked to multiple host targets. Here, we investigated the conserved rickettsial secreted effector Sca4, which was previously shown to interact with host vinculin to promote cell-to-cell spread in the model Rickettsia species R. parkeri . We discovered that Sca4 also binds the host cell endocytic factor clathrin heavy chain (CHC, CLTC ) via a conserved segment in the Sca4 N-terminus. Ablation of CLTC expression or chemical inhibition of endocytosis reduced R. parkeri cell-to-cell spread, indicating that clathrin promotes efficient spread between mammalian cells. This activity was independent of Sca4 and appeared restricted to the recipient host cell, suggesting that the Sca4-clathrin interaction also regulates another aspect of the infectious lifecycle. Indeed, R. parkeri lacking Sca4 or expressing a Sca4 truncation unable to bind clathrin had markedly reduced burdens in tick cells, hinting at a cell-type specific function for the Sca4-clathrin interaction. Sca4 homologs from diverse Rickettsia species also bound clathrin, suggesting that the function of this novel effector-host interaction may be broadly important for rickettsial infection. We conclude that Sca4 has multiple targets during infection and that rickettsiae may manipulate host endocytic machinery to facilitate several stages of their life cycles.
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Lehman SS, Verhoeve VI, Driscoll TP, Beckmann JF, Gillespie JJ. Metagenome diversity illuminates the origins of pathogen effectors. mBio 2024; 15:e0075923. [PMID: 38564675 PMCID: PMC11077975 DOI: 10.1128/mbio.00759-23] [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: 03/27/2023] [Accepted: 02/12/2024] [Indexed: 04/04/2024] Open
Abstract
Recent metagenome-assembled genome (MAG) analyses have profoundly impacted Rickettsiology systematics. The discovery of basal lineages (novel families Mitibacteraceae and Athabascaceae) with predicted extracellular lifestyles exposed an evolutionary timepoint for the transition to host dependency, which seemingly occurred independent of mitochondrial evolution. Notably, these basal rickettsiae carry the Rickettsiales vir homolog (rvh) type IV secretion system and purportedly use rvh to kill congener microbes rather than parasitize host cells as described for later-evolving rickettsial pathogens. MAG analysis also substantially increased diversity for the genus Rickettsia and delineated a sister lineage (the novel genus Tisiphia) that stands to inform on the emergence of human pathogens from protist and invertebrate endosymbionts. Herein, we probed Rickettsiales MAG and genomic diversity for the distribution of Rickettsia rvh effectors to ascertain their origins. A sparse distribution of most Rickettsia rvh effectors outside of Rickettsiaceae lineages illuminates unique rvh evolution from basal extracellular species and other rickettsial families. Remarkably, nearly every effector was found in multiple divergent forms with variable architectures, indicating profound roles for gene duplication and recombination in shaping effector repertoires in Rickettsia pathogens. Lateral gene transfer plays a prominent role in shaping the rvh effector landscape, as evinced by the discovery of many effectors on plasmids and conjugative transposons, as well as pervasive effector gene exchange between Rickettsia and Legionella species. Our study exemplifies how MAGs can yield insight into pathogen effector origins, particularly how effector architectures might become tailored to the discrete host cell functions of different eukaryotic hosts.IMPORTANCEWhile rickettsioses are deadly vector-borne human diseases, factors distinguishing Rickettsia pathogens from the innumerable bevy of environmental rickettsial endosymbionts remain lacking. Recent metagenome-assembled genome (MAG) studies revealed evolutionary timepoints for rickettsial transitions to host dependency. The rvh type IV secretion system was likely repurposed from congener killing in basal extracellular species to parasitizing host cells in later-evolving pathogens. Our analysis of MAG diversity for over two dozen rvh effectors unearthed their presence in some non-pathogens. However, most effectors were found in multiple divergent forms with variable architectures, indicating gene duplication and recombination-fashioned effector repertoires of Rickettsia pathogens. Lateral gene transfer substantially shaped pathogen effector arsenals, evinced by the discovery of effectors on plasmids and conjugative transposons, as well as pervasive effector gene exchanges between Rickettsia and Legionella species. Our study exemplifies how MAGs yield insight into pathogen effector origins and evolutionary processes tailoring effectors to eukaryotic host cell biology.
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Affiliation(s)
- Stephanie S. Lehman
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Victoria I. Verhoeve
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Timothy P. Driscoll
- Department of Biology, West Virginia University, Morgantown, West Virginia, USA
| | - John F. Beckmann
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama, USA
| | - Joseph J. Gillespie
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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7
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McGinn J, Wen A, Edwards DL, Brinkley DM, Lamason RL. An expanded genetic toolkit for inducible expression and targeted gene silencing in Rickettsia parkeri. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.15.585227. [PMID: 38559073 PMCID: PMC10980030 DOI: 10.1101/2024.03.15.585227] [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
Pathogenic species within the Rickettsia genus are transmitted to humans through arthropod vectors and cause a spectrum of diseases ranging from mild to life-threatening. Despite rickettsiae posing an emerging global health risk, the genetic requirements of their infectious life cycles remain poorly understood. A major hurdle toward building this understanding has been the lack of efficient tools for genetic manipulation, owing to the technical difficulties associated with their obligate intracellular nature. To this end, we implemented the Tet-On system to enable conditional gene expression in Rickettsia parkeri. Using Tet-On, we show inducible expression of antibiotic resistance and a fluorescent reporter. We further used this inducible promoter to screen the ability of R. parkeri to express four variants of the catalytically dead Cas9 (dCas9). We demonstrate that all four dCas9 variants can be expressed in R. parkeri and used for CRISPR interference (CRISPRi)-mediated targeted gene knockdown. We show targeted knockdown of an antibiotic resistance gene as well as the endogenous virulence factor sca2. Altogether, we have developed systems for inducible gene expression and CRISPRi-mediated gene knockdown for the first time in rickettsiae, laying the groundwork for more scalable, targeted mechanistic investigations into their infectious life cycles.
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Affiliation(s)
- Jon McGinn
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Annie Wen
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Desmond L Edwards
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - David M Brinkley
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Rebecca L Lamason
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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8
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Sit B, Lamason RL. Pathogenic Rickettsia spp. as emerging models for bacterial biology. J Bacteriol 2024; 206:e0040423. [PMID: 38315013 PMCID: PMC10883807 DOI: 10.1128/jb.00404-23] [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] [Indexed: 02/07/2024] Open
Abstract
Our understanding of free-living bacterial models like Escherichia coli far outpaces that of obligate intracellular bacteria, which cannot be cultured axenically. All obligate intracellular bacteria are host-associated, and many cause serious human diseases. Their constant exposure to the distinct biochemical niche of the host has driven the evolution of numerous specialized bacteriological and genetic adaptations, as well as innovative molecular mechanisms of infection. Here, we review the history and use of pathogenic Rickettsia species, which cause an array of vector-borne vascular illnesses, as model systems to probe microbial biology. Although many challenges remain in our studies of these organisms, the rich pathogenic and biological diversity of Rickettsia spp. constitutes a unique backdrop to investigate how microbes survive and thrive in host and vector cells. We take a bacterial-focused perspective and highlight emerging insights that relate to new host-pathogen interactions, bacterial physiology, and evolution. The transformation of Rickettsia spp. from pathogens to models demonstrates how recalcitrant microbes may be leveraged in the lab to tap unmined bacterial diversity for new discoveries. Rickettsia spp. hold great promise as model systems not only to understand other obligate intracellular pathogens but also to discover new biology across and beyond bacteria.
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Affiliation(s)
- Brandon Sit
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Rebecca L. Lamason
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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9
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Tongluan N, Engström P, Jirakanwisal K, Langohr IM, Welch MD, Macaluso KR. Critical roles of Rickettsia parkeri outer membrane protein B (OmpB) in the tick host. Infect Immun 2024; 92:e0051523. [PMID: 38206007 PMCID: PMC10863407 DOI: 10.1128/iai.00515-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 01/12/2024] Open
Abstract
Rickettsia parkeri is a pathogen of public health concern and transmitted by the Gulf Coast tick, Amblyomma maculatum. Rickettsiae are obligate intracellular bacteria that enter and replicate in diverse host cells. Rickettsial outer membrane protein B (OmpB) functions in bacterial adhesion, invasion, and avoidance of cell-autonomous immunity in mammalian cell infection, but the function of OmpB in arthropod infection is unknown. In this study, the function of R. parkeri OmpB was evaluated in the tick host. R. parkeri wild-type and R. parkeri ompBSTOP::tn (non-functional OmpB) were capillary fed to naïve A. maculatum ticks to investigate dissemination in the tick and transmission to vertebrates. Ticks exposed to R. parkeri wild-type had greater rickettsial loads in all organs than ticks exposed to R. parkeri ompBSTOP::tn at 12 h post-capillary feeding and after 1 day of feeding on host. In rats that were exposed to R. parkeri ompBSTOP::tn-infected ticks, dermal inflammation at the bite site was less compared to R. parkeri wild-type-infected ticks. In vitro, R. parkeri ompBSTOP::tn cell attachment to tick cells was reduced, and host cell invasion of the mutant was initially reduced but eventually returned to the level of R. parkeri wild-type by 90 min post-infection. R. parkeri ompBSTOP::tn and R. parkeri wild-type had similar growth kinetics in the tick cells, suggesting that OmpB is not essential for R. parkeri replication in tick cells. These results indicate that R. parkeri OmpB functions in rickettsial attachment and internalization to tick cells and pathogenicity during tick infection.
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Affiliation(s)
- Natthida Tongluan
- Department of Microbiology and Immunology, University of South Alabama, Frederick P. Whiddon College of Medicine, Mobile, Alabama, USA
| | - Patrik Engström
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Krit Jirakanwisal
- Department of Microbiology and Immunology, University of South Alabama, Frederick P. Whiddon College of Medicine, Mobile, Alabama, USA
| | - Ingeborg M. Langohr
- Department of Pathobiological Sciences, Louisiana State University, School of Veterinary Medicine, Baton Rouge, Louisiana, USA
| | - Matthew D. Welch
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Kevin R. Macaluso
- Department of Microbiology and Immunology, University of South Alabama, Frederick P. Whiddon College of Medicine, Mobile, Alabama, USA
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10
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Feng Y, Wang S, Liu X, Han Y, Xu H, Duan X, Xie W, Tian Z, Yuan Z, Wan Z, Xu L, Qin S, He K, Huang J. Geometric constraint-triggered collagen expression mediates bacterial-host adhesion. Nat Commun 2023; 14:8165. [PMID: 38071397 PMCID: PMC10710423 DOI: 10.1038/s41467-023-43827-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
Cells living in geometrically confined microenvironments are ubiquitous in various physiological processes, e.g., wound closure. However, it remains unclear whether and how spatially geometric constraints on host cells regulate bacteria-host interactions. Here, we reveal that interactions between bacteria and spatially constrained cell monolayers exhibit strong spatial heterogeneity, and that bacteria tend to adhere to these cells near the outer edges of confined monolayers. The bacterial adhesion force near the edges of the micropatterned monolayers is up to 75 nN, which is ~3 times higher than that at the centers, depending on the underlying substrate rigidities. Single-cell RNA sequencing experiments indicate that spatially heterogeneous expression of collagen IV with significant edge effects is responsible for the location-dependent bacterial adhesion. Finally, we show that collagen IV inhibitors can potentially be utilized as adjuvants to reduce bacterial adhesion and thus markedly enhance the efficacy of antibiotics, as demonstrated in animal experiments.
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Affiliation(s)
- Yuting Feng
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, 100871, Beijing, China
| | - Shuyi Wang
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, 100871, Beijing, China
| | - Xiaoye Liu
- Beijing Traditional Chinese Veterinary Engineering Center and Beijing Key Laboratory of Traditional Chinese Veterinary Medicine, Beijing University of Agriculture, 102206, Beijing, China
| | - Yiming Han
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, 100871, Beijing, China
| | - Hongwei Xu
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, 100871, Beijing, China
| | - Xiaocen Duan
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, 100871, Beijing, China
| | - Wenyue Xie
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, 100871, Beijing, China
| | - Zhuoling Tian
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Zuoying Yuan
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, 100871, Beijing, China
| | - Zhuo Wan
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, 100871, Beijing, China
| | - Liang Xu
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Siying Qin
- School of Life Sciences, Peking University, 100871, Beijing, China
| | - Kangmin He
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 100101, Beijing, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Jianyong Huang
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, 100871, Beijing, China.
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11
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Mezher M, Dumbali S, Fenn I, Lamb C, Miller C, Sharmin S, Cabe JI, Bejar-Padilla V, Conway D, Maruthamuthu V. Vinculin is essential for sustaining normal levels of endogenous forces at cell-cell contacts. Biophys J 2023; 122:4518-4527. [PMID: 38350000 PMCID: PMC10719050 DOI: 10.1016/j.bpj.2023.10.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 09/11/2023] [Accepted: 10/25/2023] [Indexed: 02/15/2024] Open
Abstract
Transmission of cell-generated (i.e., endogenous) tension at cell-cell contacts is crucial for tissue shape changes during morphogenesis and adult tissue repair in tissues such as epithelia. E-cadherin-based adhesions at cell-cell contacts are the primary means by which endogenous tension is transmitted between cells. The E-cadherin-β-catenin-α-catenin complex mechanically couples to the actin cytoskeleton (and thereby the cell's contractile machinery) both directly and indirectly. However, the key adhesion constituents required for substantial endogenous force transmission at these adhesions in cell-cell contacts are unclear. Due to the role of α-catenin as a mechanotransducer that recruits vinculin at cell-cell contacts, we expected α-catenin to be essential for sustaining normal levels of force transmission. Instead, using the traction force imbalance method to determine the inter-cellular force at a single cell-cell contact between cell pairs, we found that it is vinculin that is essential for sustaining normal levels of endogenous force transmission, with absence of vinculin decreasing the inter-cellular tension by over 50%. Our results constrain the potential mechanical pathways of force transmission at cell-cell contacts and suggest that vinculin can transmit forces at E-cadherin adhesions independent of α-catenin, possibly through β-catenin. Furthermore, we tested the ability of lateral cell-cell contacts to withstand external stretch and found that both vinculin and α-catenin are essential to maintain cell-cell contact stability under external forces.
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Affiliation(s)
- Mazen Mezher
- Mechanical & Aerospace Engineering, Old Dominion University, Norfolk, Virginia
| | - Sandeep Dumbali
- Mechanical & Aerospace Engineering, Old Dominion University, Norfolk, Virginia
| | - Ian Fenn
- Mechanical & Aerospace Engineering, Old Dominion University, Norfolk, Virginia
| | - Carter Lamb
- Mechanical & Aerospace Engineering, Old Dominion University, Norfolk, Virginia
| | - Conrad Miller
- Mechanical & Aerospace Engineering, Old Dominion University, Norfolk, Virginia
| | - Saika Sharmin
- Mechanical & Aerospace Engineering, Old Dominion University, Norfolk, Virginia
| | - Jolene I Cabe
- Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia
| | - Vidal Bejar-Padilla
- Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia
| | - Daniel Conway
- Biomedical Engineering, The Ohio State University, Columbus, Ohio
| | - Venkat Maruthamuthu
- Mechanical & Aerospace Engineering, Old Dominion University, Norfolk, Virginia.
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12
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Sanderlin AG, Margolis HK, Meyer AF, Lamason RL. Cell-selective proteomics reveal novel effectors secreted by an obligate intracellular bacterial pathogen. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.17.567466. [PMID: 38014272 PMCID: PMC10680844 DOI: 10.1101/2023.11.17.567466] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Pathogenic bacteria secrete protein effectors to hijack host machinery and remodel their infectious niche. Rickettsia spp. are obligate intracellular bacteria that can cause life-threatening disease, but their absolute dependence on the host cell environment has impeded discovery of rickettsial effectors and their host targets. We implemented bioorthogonal non-canonical amino acid tagging (BONCAT) during R. parkeri infection to selectively label, isolate, and identify secreted effectors. As the first use of BONCAT in an obligate intracellular bacterium, our screen more than doubles the number of experimentally validated effectors for R. parkeri. The novel secreted rickettsial factors (Srfs) we identified include Rickettsia-specific proteins of unknown function that localize to the host cytoplasm, mitochondria, and ER. We further show that one such effector, SrfD, interacts with the host Sec61 translocon. Altogether, our work uncovers a diverse set of previously uncharacterized rickettsial effectors and lays the foundation for a deeper exploration of the host-pathogen interface.
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Affiliation(s)
- Allen G. Sanderlin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Hannah K. Margolis
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Abigail F. Meyer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Rebecca L. Lamason
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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Beliavskaia A, Tan KK, Sinha A, Husin NA, Lim FS, Loong SK, Bell-Sakyi L, Carlow CKS, AbuBakar S, Darby AC, Makepeace BL, Khoo JJ. Metagenomics of culture isolates and insect tissue illuminate the evolution of Wolbachia, Rickettsia and Bartonella symbionts in Ctenocephalides spp. fleas. Microb Genom 2023; 9:mgen001045. [PMID: 37399133 PMCID: PMC10438800 DOI: 10.1099/mgen.0.001045] [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: 02/08/2023] [Accepted: 05/16/2023] [Indexed: 07/05/2023] Open
Abstract
While fleas are often perceived simply as a biting nuisance and a cause of allergic dermatitis, they represent important disease vectors worldwide, especially for bacterial zoonoses such as plague (transmitted by rodent fleas) and some of the rickettsioses and bartonelloses. The cosmopolitan cat (Ctenocephalides felis ) and dog (Ctenocephalides canis ) fleas, as well as Ctenocephalides orientis (restricted to tropical and subtropical Asia), breed in human dwellings and are vectors of cat-scratch fever (caused by Bartonella spp.) and Rickettsia spp., including Rickettsia felis (agent of flea-borne spotted fever) and Rickettsia asembonensis , a suspected pathogen. These Rickettsia spp. are members of a phylogenetic clade known as the ‘transitional group’, which includes both human pathogens and arthropod-specific endosymbionts. The relatively depauperate flea microbiome can also contain other endosymbionts, including a diverse range of Wolbachia strains. Here, we present circularized genome assemblies for two C. orientis -derived pathogens (Bartonella clarridgeiae and R. asembonensis ) from Malaysia, a novel Wolbachia strain (w Cori), and the C. orientis mitochondrion; all were obtained by direct metagenomic sequencing of flea tissues. Moreover, we isolated two Wolbachia strains from Malaysian C. felis into tick cell culture and recovered circularized genome assemblies for both, one of which (w CfeF) is newly sequenced. We demonstrate that the three Wolbachia strains are representatives of different major clades (‘supergroups’), two of which appear to be flea-specific. These Wolbachia genomes exhibit unique combinations of features associated with reproductive parasitism or mutualism, including prophage WO, cytoplasmic incompatibility factors and the biotin operon of obligate intracellular microbes. The first circularized assembly for R. asembonensis includes a plasmid with a markedly different structure and gene content compared to the published plasmid; moreover, this novel plasmid was also detected in cat flea metagenomes from the USA. Analysis of loci under positive selection in the transitional group revealed genes involved in host–pathogen interactions that may facilitate host switching. Finally, the first B. clarridgeiae genome from Asia exhibited large-scale genome stability compared to isolates from other continents, except for SNPs in regions predicted to mediate interactions with the vertebrate host. These findings highlight the paucity of data on the genomic diversity of Ctenocephalides -associated bacteria and raise questions regarding how interactions between members of the flea microbiome might influence vector competence.
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Affiliation(s)
- Alexandra Beliavskaia
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L3 5RF, UK
| | - Kim-Kee Tan
- Tropical Infectious Diseases Research & Education Centre (TIDREC), Higher Institution Centre of Excellence (HICoE), Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Amit Sinha
- New England Biolabs, Ipswich, Massachusetts, 01938, USA
| | - Nurul Aini Husin
- Tropical Infectious Diseases Research & Education Centre (TIDREC), Higher Institution Centre of Excellence (HICoE), Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Fang Shiang Lim
- Tropical Infectious Diseases Research & Education Centre (TIDREC), Higher Institution Centre of Excellence (HICoE), Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Shih Keng Loong
- Tropical Infectious Diseases Research & Education Centre (TIDREC), Higher Institution Centre of Excellence (HICoE), Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Lesley Bell-Sakyi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L3 5RF, UK
| | | | - Sazaly AbuBakar
- Tropical Infectious Diseases Research & Education Centre (TIDREC), Higher Institution Centre of Excellence (HICoE), Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Alistair C. Darby
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L3 5RF, UK
| | - Benjamin L. Makepeace
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L3 5RF, UK
| | - Jing Jing Khoo
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L3 5RF, UK
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14
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Kim Y, Clemens EG, Farner JM, Londono-Barbaran A, Grab DJ, Dumler JS. Spotted fever rickettsia-induced microvascular endothelial barrier dysfunction is delayed by the calcium channel blocker benidipine. Biochem Biophys Res Commun 2023; 663:96-103. [PMID: 37121130 PMCID: PMC10362780 DOI: 10.1016/j.bbrc.2023.04.045] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 04/17/2023] [Indexed: 05/02/2023]
Abstract
The tick-borne bacterium Rickettsia parkeri is an obligate intracellular pathogen that belongs to spotted fever group rickettsia (SFGR). The SFG pathogens are characterized by their ability to infect and rapidly proliferate inside host vascular endothelial cells that eventually result in impairment of vascular endothelium barrier functions. Benidipine, a wide range dihydropyridine calcium channel blocker, is used to prevent and treat cardiovascular diseases. In this study, we tested whether benidipine has protective effects against rickettsia-induced microvascular endothelial cell barrier dysfunction in vitro. We utilized an in vitro vascular model consisting of transformed human brain microvascular endothelial cells (tHBMECs) and continuously monitored transendothelial electric resistance (TEER) across the cell monolayer. We found that during the late stages of infection when we observed TEER decrease and when there was a gradual increase of the cytoplasmic [Ca2+], benidipine prevented these rickettsia-induced effects. In contrast, nifedipine, another cardiovascular dihydropyridine channel blocker specific for L-type Ca2+ channels, did not prevent R. parkeri-induced drop of TEER. Additionally, neither drug was bactericidal. These data suggest that growth of R. parkeri inside endothelial cells is associated with impairment of endothelial cell monolayer integrity due to Ca2+ flooding through specific, benidipine-sensitive T- or N/Q-type Ca2+ channels but not through nifedipine-sensitive L-type Ca2+ channels. Further study will be required to discern the exact nature of the Ca2+ channels and Ca2+ transporting system(s) involved, any contributions of the pathogen toward this process, as well as the suitability of benidipine and new dihydropyridine derivatives as complimentary therapeutic drugs against Rickettsia-induced vascular failure.
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Affiliation(s)
- Yuri Kim
- Henry M. Jackson Foundation for the Advancement of Military Medicine, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA; Uniformed Services of the Health Sciences, Department of Pathology, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
| | - Emily G Clemens
- Uniformed Services of the Health Sciences, Department of Pathology, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
| | - Jennifer M Farner
- Henry M. Jackson Foundation for the Advancement of Military Medicine, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA; Uniformed Services of the Health Sciences, Department of Pathology, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
| | - Andres Londono-Barbaran
- Henry M. Jackson Foundation for the Advancement of Military Medicine, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA; Uniformed Services of the Health Sciences, Department of Pathology, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
| | - Dennis J Grab
- Uniformed Services of the Health Sciences, Department of Pathology, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
| | - J Stephen Dumler
- Uniformed Services of the Health Sciences, Department of Pathology, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
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15
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Acevedo-Sánchez Y, Woida PJ, Kraemer S, Lamason RL. An obligate intracellular bacterial pathogen forms a direct, interkingdom membrane contact site. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.05.543771. [PMID: 37333133 PMCID: PMC10274737 DOI: 10.1101/2023.06.05.543771] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Interorganelle communication regulates cellular homeostasis through the formation of tightly-associated membrane contact sites 1-3. Prior work has identified several ways that intracellular pathogens alter contacts between eukaryotic membranes 4-6, but there is no existing evidence for contact sites spanning eukaryotic and prokaryotic membranes. Here, using a combination of live-cell microscopy and transmission and focused-ion-beam scanning electron microscopy, we demonstrate that the intracellular bacterial pathogen Rickettsia parkeri forms a direct membrane contact site between its bacterial outer membrane and the rough endoplasmic reticulum (ER), with tethers that are approximately 55 nm apart. Depletion of the ER-specific tethers VAPA and VAPB reduced the frequency of rickettsia-ER contacts, suggesting these interactions mimic organelle-ER contacts. Overall, our findings illuminate a direct, interkingdom membrane contact site uniquely mediated by rickettsia that seems to mimic traditional host MCSs.
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Affiliation(s)
| | - Patrick J. Woida
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Stephan Kraemer
- Center for Nanoscale Systems, Harvard University, Cambridge, MA, USA
| | - Rebecca L. Lamason
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
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16
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Figueroa-Cuilan WM, Irazoki O, Feeley M, Smith E, Nguyen T, Cava F, Goley ED. Quantitative analysis of morphogenesis and growth dynamics in an obligate intracellular bacterium. Mol Biol Cell 2023; 34:ar69. [PMID: 37017481 PMCID: PMC10295487 DOI: 10.1091/mbc.e23-01-0023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 04/06/2023] Open
Abstract
Obligate intracellular bacteria of the order Rickettsiales include important human pathogens. However, our understanding of the biology of Rickettsia species is limited by challenges imposed by their obligate intracellular lifestyle. To overcome this roadblock, we developed methods to assess cell wall composition, growth, and morphology of Rickettsia parkeri, a human pathogen in the spotted fever group of the Rickettsia genus. Analysis of the cell wall of R. parkeri revealed unique features that distinguish it from free-living alphaproteobacteria. Using a novel fluorescence microscopy approach, we quantified R. parkeri morphology in live host cells and found that the fraction of the population undergoing cell division decreased over the course of infection. We further demonstrated the feasibility of localizing fluorescence fusions, for example, to the cell division protein ZapA, in live R. parkeri for the first time. To evaluate population growth kinetics, we developed an imaging-based assay that improves on the throughput and resolution of other methods. Finally, we applied these tools to quantitatively demonstrate that the actin homologue MreB is required for R. parkeri growth and rod shape. Collectively, a toolkit was developed of high-throughput, quantitative tools to understand growth and morphogenesis of R. parkeri that is translatable to other obligate intracellular bacteria.
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Affiliation(s)
- Wanda M. Figueroa-Cuilan
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Oihane Irazoki
- Laboratory for Molecular Infection Medicine, Umeå Center for Microbial Research, Department of Molecular Biology, Umeå University, SE-901 87, Umeå, Sweden
| | - Marissa Feeley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Erika Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Trung Nguyen
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine, Umeå Center for Microbial Research, Department of Molecular Biology, Umeå University, SE-901 87, Umeå, Sweden
| | - Erin D. Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
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17
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Riffaud CM, Rucks EA, Ouellette SP. Persistence of obligate intracellular pathogens: alternative strategies to overcome host-specific stresses. Front Cell Infect Microbiol 2023; 13:1185571. [PMID: 37284502 PMCID: PMC10239878 DOI: 10.3389/fcimb.2023.1185571] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/05/2023] [Indexed: 06/08/2023] Open
Abstract
In adapting to the intracellular niche, obligate intracellular bacteria usually undergo a reduction of genome size by eliminating genes not needed for intracellular survival. These losses can include, for example, genes involved in nutrient anabolic pathways or in stress response. Living inside a host cell offers a stable environment where intracellular bacteria can limit their exposure to extracellular effectors of the immune system and modulate or outright inhibit intracellular defense mechanisms. However, highlighting an area of vulnerability, these pathogens are dependent on the host cell for nutrients and are very sensitive to conditions that limit nutrient availability. Persistence is a common response shared by evolutionarily divergent bacteria to survive adverse conditions like nutrient deprivation. Development of persistence usually compromises successful antibiotic therapy of bacterial infections and is associated with chronic infections and long-term sequelae for the patients. During persistence, obligate intracellular pathogens are viable but not growing inside their host cell. They can survive for a long period of time such that, when the inducing stress is removed, reactivation of their growth cycles resumes. Given their reduced coding capacity, intracellular bacteria have adapted different response mechanisms. This review gives an overview of the strategies used by the obligate intracellular bacteria, where known, which, unlike model organisms such as E. coli, often lack toxin-antitoxin systems and the stringent response that have been linked to a persister phenotype and amino acid starvation states, respectively.
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18
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Kask L, Påhlson C, Staxäng K, Nilsson K. Signatures in in vitro infection of NSC-34 mouse neurons and their cell nucleus with Rickettsia helvetica. BMC Microbiol 2023; 23:113. [PMID: 37085774 PMCID: PMC10120103 DOI: 10.1186/s12866-023-02859-0] [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: 11/19/2022] [Accepted: 04/11/2023] [Indexed: 04/23/2023] Open
Abstract
BACKGROUND Rickettsia helvetica, a spotted fever rickettsia, is transmitted to humans via ticks in Europe, North Africa, and Asia. The central nervous system is a crucial target for rickettsial diseases, which has been reported for 12 of the 31 species, of which R. helvetica is one. This study aimed, in an experimental model, to identify characteristics of R. helvetica infection in a mouse neuronal cell line, NSC-34. RESULTS NSC-34, a fusion cell line of mouse motor spinal cord neurons and neuroblastoma cells, was used as a model. Propagation of R. helvetica in neurons was confirmed. Short actin tails were shown at the polar end of the bacteria, which makes it likely that they can move intracellularly, and even spread between cells. Another protein, Sca4, which with the cell adhesion protein vinculin enables the passage of the cell membrane, was expressed during infection. No significant increase in TNFα levels was seen in the infected neurons, which is of interest because TNFα protects the host cell from infection-induced apoptotic death which is crucial for host cell survival. The bacteria were also shown to invade and grow in the cell nucleus of the neuron. CONCLUSIONS The findings suggest that a R. helvetica infection may be harmful to NSC-34 neurons under these in vitro conditions, but the full effects of the infection on the cell need to be studied further, also on human neurons, to also understand the possible significance of this infection in relation to pathogenetic mechanisms.
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Affiliation(s)
- Lena Kask
- Department of Medical Sciences, Section of Clinical Microbiology, Uppsala University, Uppsala, Sweden
| | - Carl Påhlson
- Department of Medical Sciences, Section of Clinical Microbiology, Uppsala University, Uppsala, Sweden
| | - Karin Staxäng
- Department of Immunology, Genetics and Pathology-Biovis Platform, Uppsala University, Uppsala, Sweden
| | - Kenneth Nilsson
- Department of Medical Sciences, Section of Clinical Microbiology, Uppsala University, Uppsala, Sweden.
- Department of Medical Sciences, Section of Infectious Diseases, Uppsala University, Uppsala, Sweden.
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19
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Gillespie JJ, Salje J. Orientia and Rickettsia: different flowers from the same garden. Curr Opin Microbiol 2023; 74:102318. [PMID: 37080115 DOI: 10.1016/j.mib.2023.102318] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 04/22/2023]
Abstract
Recent discoveries of basal extracellular Rickettsiales have illuminated divergent evolutionary paths to host dependency in later-evolving lineages. Family Rickettsiaceae, primarily comprised of numerous protist- and invertebrate-associated species, also includes human pathogens from two genera, Orientia and Rickettsia. Once considered sister taxa, these bacteria form distinct lineages with newly appreciated lifestyles and morphological traits. Contrasting other rickettsial human pathogens in Family Anaplasmataceae, Orientia and Rickettsia species do not reside in host-derived vacuoles and lack glycolytic potential. With only a few described mechanisms, strategies for commandeering host glycolysis to support cytosolic growth remain to be discovered. While regulatory systems for this unique mode of intracellular parasitism are unclear, conjugative transposons unique to Orientia and Rickettsia species provide insights that are critical for determining how these obligate intracellular pathogens overtake eukaryotic cytosol.
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Affiliation(s)
- Joseph J Gillespie
- Department of Microbiology and Immunology, School of Medicine, University of Maryland Baltimore, USA.
| | - Jeanne Salje
- Department of Biochemistry, Department of Pathology, and Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK.
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20
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Verhoeve VI, Lehman SS, Driscoll TP, Beckmann JF, Gillespie JJ. Metagenome diversity illuminates origins of pathogen effectors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.26.530123. [PMID: 36909625 PMCID: PMC10002696 DOI: 10.1101/2023.02.26.530123] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Recent metagenome assembled genome (MAG) analyses have profoundly impacted Rickettsiology systematics. Discovery of basal lineages (Mitibacteraceae and Athabascaceae) with predicted extracellular lifestyles reveals an evolutionary timepoint for the transition to host dependency, which occurred independent of mitochondrial evolution. Notably, these basal rickettsiae carry the Rickettsiales vir homolog (rvh) type IV secretion system (T4SS) and purportedly use rvh to kill congener microbes rather than parasitize host cells as described for derived rickettsial pathogens. MAG analysis also substantially increased diversity for genus Rickettsia and delineated a basal lineage (Tisiphia) that stands to inform on the rise of human pathogens from protist and invertebrate endosymbionts. Herein, we probed Rickettsiales MAG and genomic diversity for the distribution of Rickettsia rvh effectors to ascertain their origins. A sparse distribution of most Rickettsia rvh effectors outside of Rickettsiaceae lineages indicates unique rvh evolution from basal extracellular species and other rickettsial families. Remarkably, nearly every effector was found in multiple divergent forms with variable architectures, illuminating profound roles for gene duplication and recombination in shaping effector repertoires in Rickettsia pathogens. Lateral gene transfer plays a prominent role shaping the rvh effector landscape, as evinced by the discover of many effectors on plasmids and conjugative transposons, as well as pervasive effector gene exchange between Rickettsia and Legionella species. Our study exemplifies how MAGs can provide incredible insight on the origins of pathogen effectors and how their architectural modifications become tailored to eukaryotic host cell biology.
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Affiliation(s)
- Victoria I Verhoeve
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Stephanie S Lehman
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Timothy P Driscoll
- Department of Biology, West Virginia University, Morgantown, West Virginia, USA
| | - John F Beckmann
- Microbiology and Immunology, University of South Alabama, Mobile, AL, USA
| | - Joseph J Gillespie
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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21
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Kostow N, Welch MD. Manipulation of host cell plasma membranes by intracellular bacterial pathogens. Curr Opin Microbiol 2023; 71:102241. [PMID: 36442349 PMCID: PMC10074913 DOI: 10.1016/j.mib.2022.102241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 10/20/2022] [Accepted: 10/31/2022] [Indexed: 11/26/2022]
Abstract
Manipulation of the host cell plasma membrane is critical during infection by intracellular bacterial pathogens, particularly during bacterial entry into and exit from host cells. To manipulate host cells, bacteria deploy secreted proteins that modulate or modify host cell components. Here, we review recent advances that suggest common themes by which bacteria manipulate the host cell plasma membrane. One theme is that bacteria use diverse strategies to target or influence host cell plasma membrane composition and shape. A second theme is that bacteria take advantage of host cell plasma membrane-associated pathways such as signal transduction, endocytosis, and exocytosis. Future investigation into how bacterial and host factors contribute to plasma membrane manipulation by bacterial pathogens will reveal new insights into pathogenesis and fundamental principles of plasma membrane biology.
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Affiliation(s)
- Nora Kostow
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Matthew D Welch
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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22
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Muenkel M, Aparicio-Yuste R, Tal MC, Kraiczy P, Bastounis EE. Spatiotemporal characterization of endothelial cell motility and physical forces during exposure to Borrelia burgdorferi. STAR Protoc 2022; 3:101832. [DOI: 10.1016/j.xpro.2022.101832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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23
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Helminiak L, Mishra S, Keun Kim H. Pathogenicity and virulence of Rickettsia. Virulence 2022; 13:1752-1771. [PMID: 36208040 PMCID: PMC9553169 DOI: 10.1080/21505594.2022.2132047] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 09/16/2022] [Accepted: 09/29/2022] [Indexed: 12/24/2022] Open
Abstract
Rickettsiae include diverse Gram-negative microbial species that exhibit obligatory intracellular lifecycles between mammalian hosts and arthropod vectors. Human infections with arthropod-borne Rickettsia continue to cause significant morbidity and mortality as recent environmental changes foster the proliferation of arthropod vectors and increased exposure to humans. However, the technical difficulties in working with Rickettsia have delayed our progress in understanding the molecular mechanisms involved in rickettsial pathogenesis and disease transmission. Recent advances in developing genetic tools for Rickettsia have enabled investigators to identify virulence genes, uncover molecular functions, and characterize host responses to rickettsial determinants. Therefore, continued efforts to determine virulence genes and their biological functions will help us understand the underlying mechanisms associated with arthropod-borne rickettsioses.
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Affiliation(s)
| | | | - Hwan Keun Kim
- Center for Infectious Diseases, Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, USA
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24
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Laukaitis HJ, Cooper TT, Suwanbongkot C, Verhoeve VI, Kurtti TJ, Munderloh UG, Macaluso KR. Transposon mutagenesis of Rickettsia felis sca1 confers a distinct phenotype during flea infection. PLoS Pathog 2022; 18:e1011045. [PMID: 36542675 DOI: 10.1371/journal.ppat.1011045] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 01/05/2023] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
Since its recognition in 1994 as the causative agent of human flea-borne spotted fever, Rickettsia felis, has been detected worldwide in over 40 different arthropod species. The cat flea, Ctenocephalides felis, is a well-described biological vector of R. felis. Unique to insect-borne rickettsiae, R. felis can employ multiple routes of infection including inoculation via salivary secretions and potentially infectious flea feces into the skin of vertebrate hosts. Yet, little is known of the molecular interactions governing flea infection and subsequent transmission of R. felis. While the obligate intracellular nature of rickettsiae has hampered the function of large-scale mutagenesis strategies, studies have shown the efficiency of mariner-based transposon systems in Rickettsiales. Thus, this study aimed to assess R. felis genetic mutants in a flea transmission model to elucidate genes involved in vector infection. A Himar1 transposase was used to generate R. felis transformants, in which subsequent genome sequencing revealed a transposon insertion near the 3' end of sca1. Alterations in sca1 expression resulted in unique infection phenotypes. While the R. felis sca1::tn mutant portrayed enhanced growth kinetics compared to R. felis wild-type during in vitro culture, rickettsial loads were significantly reduced during flea infection. As a consequence of decreased rickettsial loads within infected donor fleas, R. felis sca1::tn exhibited limited transmission potential. Thus, the use of a biologically relevant model provides evidence of a defective phenotype associated with R. felis sca1::tn during flea infection.
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Affiliation(s)
- Hanna J Laukaitis
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America.,Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Triston T Cooper
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
| | - Chanakan Suwanbongkot
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
| | - Victoria I Verhoeve
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Timothy J Kurtti
- Department of Entomology, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Ulrike G Munderloh
- Department of Entomology, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Kevin R Macaluso
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
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Hartland EL, Ghosal D, Giogha C. Manipulation of epithelial cell architecture by the bacterial pathogens Listeria and Shigella. Curr Opin Cell Biol 2022; 79:102131. [PMID: 36215855 DOI: 10.1016/j.ceb.2022.102131] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 08/22/2022] [Accepted: 09/06/2022] [Indexed: 01/31/2023]
Abstract
Subversion of the host cell cytoskeleton is a virulence attribute common to many bacterial pathogens. On mucosal surfaces, bacteria have evolved distinct ways of interacting with the polarised epithelium and manipulating host cell structure to propagate infection. For example, Shigella and Listeria induce cytoskeletal changes to induce their own uptake into enterocytes in order to replicate within an intracellular environment and then spread from cell-to-cell by harnessing the host actin cytoskeleton. In this review, we highlight some recent studies that advance our understanding of the role of the host cell cytoskeleton in the mechanical and molecular processes of pathogen invasion, cell-to-cell spread and the impact of infection on epithelial intercellular tension and innate mucosal defence.
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Affiliation(s)
- Elizabeth L Hartland
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia; Department of Molecular and Translational Science, Monash University, Clayton, Victoria, Australia.
| | - Debnath Ghosal
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Cristina Giogha
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia; Department of Molecular and Translational Science, Monash University, Clayton, Victoria, Australia
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26
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Huang D, Luo J, OuYang X, Song L. Subversion of host cell signaling: The arsenal of Rickettsial species. Front Cell Infect Microbiol 2022; 12:995933. [PMID: 36389139 PMCID: PMC9659576 DOI: 10.3389/fcimb.2022.995933] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 10/04/2022] [Indexed: 10/10/2023] Open
Abstract
Rickettsia is a genus of nonmotile, Gram-negative, non-spore-forming, highly pleomorphic bacteria that cause severe epidemic rickettsioses. The spotted fever group and typhi group are major members of the genus Rickettsia. Rickettsial species from the two groups subvert diverse host cellular processes, including membrane dynamics, actin cytoskeleton dynamics, phosphoinositide metabolism, intracellular trafficking, and immune defense, to promote their host colonization and intercellular transmission through secreted effectors (virulence factors). However, lineage-specific rickettsiae have exploited divergent strategies to accomplish such challenging tasks and these elaborated strategies focus on distinct host cell processes. In the present review, we summarized current understandings of how different rickettsial species employ their effectors' arsenal to affect host cellular processes in order to promote their own replication or to avoid destruction.
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Affiliation(s)
- Dan Huang
- Department of Respiratory Medicine, Center of Pathogen Biology and Infectious Disease, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
| | - Jingjing Luo
- Department of Respiratory Medicine, Center of Pathogen Biology and Infectious Disease, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
| | - Xuan OuYang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Lei Song
- Department of Respiratory Medicine, Center of Pathogen Biology and Infectious Disease, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
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27
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Pan YS, Cui XM, Du LF, Xia LY, Du CH, Bell-Sakyi L, Zhang MZ, Zhu DY, Dong Y, Wei W, Zhao L, Sun Y, Lv QY, Ye RZ, He ZH, Wang Q, Li LJ, Yao MG, Xiong T, Jiang JF, Cao WC, Jia N. Coinfection of Two Rickettsia Species in a Single Tick Species Provides New Insight into Rickettsia- Rickettsia and Rickettsia-Vector Interactions. Microbiol Spectr 2022; 10:e0232322. [PMID: 36173317 PMCID: PMC9603609 DOI: 10.1128/spectrum.02323-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 09/15/2022] [Indexed: 01/04/2023] Open
Abstract
Rickettsiae are obligate intracellular bacteria that can cause life-threatening illnesses. There is an ongoing debate as to whether established infections by one Rickettsia species preclude the maintenance of the second species in ticks. Here, we identified two Rickettsia species in inoculum from Haemaphysalis montgomeryi ticks and subsequently obtained pure isolates of each species by plaque selection. The two isolates were classified as a transitional group and spotted fever group rickettsiae and named Rickettsia hoogstraalii str CS and Rickettsia rhipicephalii str EH, respectively. The coinfection of these two Rickettsia species was detected in 25.6% of individual field-collected H. montgomeryi. In cell culture infection models, R. hoogstraalii str CS overwhelmed R. rhipicephalii str EH with more obvious cytopathic effects, faster plaque formation, and increased cellular growth when cocultured, and R. hoogstraalii str CS seemed to polymerize actin tails differently from R. rhipicephalii str EH in vitro. This work provides a model to investigate the mechanisms of both Rickettsia-Rickettsia and Rickettsia-vector interactions. IMPORTANCE The rickettsiae are a group of obligate intracellular Gram-negative bacteria that include human pathogens causing an array of clinical symptoms and even death. There is an important question in the field, that is whether one infection can block the superinfection of other rickettsiae. This work demonstrated the coinfection of two Rickettsia species in individual ticks and further highlighted that testing the rickettsial competitive exclusion hypothesis will undoubtedly be a promising area as methods for bioengineering and pathogen biocontrol become amenable for rickettsiae.
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Affiliation(s)
- Yu-Sheng Pan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Xiao-Ming Cui
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Li-Feng Du
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
- Institute of EcoHealth, School of Public Health, Shandong University, Jinan, Shandong, People’s Republic of China
| | - Luo-Yuan Xia
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
- Institute of EcoHealth, School of Public Health, Shandong University, Jinan, Shandong, People’s Republic of China
| | - Chun-Hong Du
- Yunnan Institute for Endemic Diseases Control and Prevention, Dali, Yunnan, People’s Republic of China
| | - Lesley Bell-Sakyi
- Department of Infection Biology and Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Ming-Zhu Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Dai-Yun Zhu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Yi Dong
- Yunnan Institute for Endemic Diseases Control and Prevention, Dali, Yunnan, People’s Republic of China
| | - Wei Wei
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Lin Zhao
- Institute of EcoHealth, School of Public Health, Shandong University, Jinan, Shandong, People’s Republic of China
| | - Yi Sun
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Qing-Yu Lv
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Run-Ze Ye
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Zhi-Hai He
- Yunnan Institute for Endemic Diseases Control and Prevention, Dali, Yunnan, People’s Republic of China
| | - Qian Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Liang-Jing Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Ming-Guo Yao
- Yunnan Institute for Endemic Diseases Control and Prevention, Dali, Yunnan, People’s Republic of China
| | - Tao Xiong
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Jia-Fu Jiang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Wu-Chun Cao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Na Jia
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
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28
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A Vaccine for Canine Rocky Mountain Spotted Fever: An Unmet One Health Need. Vaccines (Basel) 2022; 10:vaccines10101626. [PMID: 36298491 PMCID: PMC9610744 DOI: 10.3390/vaccines10101626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 09/22/2022] [Accepted: 09/25/2022] [Indexed: 11/17/2022] Open
Abstract
Outbreaks of life-threatening Rocky Mountain spotted fever in humans and dogs associated with a canine-tick maintenance cycle constitute an important One Health opportunity. The reality of the problem has been observed strikingly in Mexico, Brazil, Colombia, and Native American tribal lands in Arizona. The brown dog tick, Rhipicephalus sanguineus sensu lato, acquires the rickettsia from bacteremic dogs and can maintain the bacterium transtadially to the next tick stage. The subsequent adult tick can then transmit infection to a new host, as shown by guinea pig models. These brown dog ticks maintain spotted fever group rickettsiae transovarially through many generations, thus serving as both vector and reservoir. Vaccine containing whole-killed R. rickettsii does not stimulate sufficient immunity. Studies of Rickettsia subunit antigens have demonstrated that conformationally preserved outer-membrane autotransporter proteins A and B are the leading vaccine candidates. The possibility of a potentially safe and effective live attenuated vaccine has only begun to be explored as gene knockout methods are applied to these obligately intracellular pathogens.
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Abstract
Ticks are hematophagous ectoparasites capable of transmitting multiple human pathogens. Environmental changes have supported the expansion of ticks into new geographical areas that have become the epicenters of tick-borne diseases (TBDs). The spotted fever group (SFG) of Rickettsia frequently infects ticks and causes tick-transmitted rickettsioses in areas of endemicity where ixodid ticks support host transmission during blood feeding. Ticks also serve as a reservoir for SFG Rickettsia. Among the members of SFG Rickettsia, R. rickettsii causes Rocky Mountain spotted fever (RMSF), the most lethal TBD in the United States. Cases of RMSF have been reported for over a century in association with several species of ticks in the United States. However, the isolation of R. rickettsii from ticks has decreased, and recent serological and epidemiological studies suggest that novel species of SFG Rickettsia are responsible for the increased number of cases of RMSF-like rickettsioses in the United States. Recent analyses of rickettsial genomes and advances in genetic and molecular studies of Rickettsia provided insights into the biology of Rickettsia with the identification of conserved and unique putative virulence genes involved in the rickettsial life cycle. Thus, understanding Rickettsia-host-tick interactions mediating successful disease transmission and pathogenesis for SFG rickettsiae remains an active area of research. This review summarizes recent advances in understanding how SFG Rickettsia species coopt and manipulate ticks and mammalian hosts to cause rickettsioses, with a particular emphasis on newly described or emerging SFG Rickettsia species.
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30
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Yuste RA, Muenkel M, Axarlis K, Gómez Benito MJ, Reuss A, Blacker G, Tal MC, Kraiczy P, Bastounis EE. Borrelia burgdorferi modulates the physical forces and immunity signaling in endothelial cells. iScience 2022; 25:104793. [PMID: 35992087 PMCID: PMC9389243 DOI: 10.1016/j.isci.2022.104793] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/09/2022] [Accepted: 07/13/2022] [Indexed: 12/04/2022] Open
Abstract
Borrelia burgdorferi (Bb), a vector-borne bacterial pathogen and the causative agent of Lyme disease, can spread to distant tissues in the human host by traveling in and through monolayers of endothelial cells (ECs) lining the vasculature. To examine whether Bb alters the physical forces of ECs to promote its dissemination, we exposed ECs to Bb and observed a sharp and transient increase in EC traction and intercellular forces, followed by a prolonged decrease in EC motility and physical forces. All variables returned to baseline at 24 h after exposure. RNA sequencing analysis revealed an upregulation of innate immune signaling pathways during early but not late Bb exposure. Exposure of ECs to heat-inactivated Bb recapitulated only the early weakening of EC mechanotransduction. The differential responses to live versus heat-inactivated Bb indicate a tight interplay between innate immune signaling and physical forces in host ECs and suggest their active modulation by Bb. Early exposure to Borrelia decreases endothelial cell motility and physical forces Early exposure to Borrelia also upregulates the host’s innate immune signaling pathways Host cell mechanics and signaling return to steady state at late exposure times Exposure to dead bacteria steadily reduces motility and physical forces of host cells
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31
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Kostow N, Welch MD. Plasma membrane protrusions mediate host cell-cell fusion induced by Burkholderia thailandensis. Mol Biol Cell 2022; 33:ar70. [PMID: 35594178 DOI: 10.1091/mbc.e22-02-0056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cell-cell fusion is important for biological processes including fertilization, development, immunity, and microbial pathogenesis. Bacteria in the pseudomallei group of the Burkholderia species, including B. thailandensis, spread between host cells by inducing cell-cell fusion. Previous work showed that B. thailandensis-induced cell-cell fusion requires intracellular bacterial motility and a bacterial protein secretion apparatus called the type VI secretion system-5 (T6SS-5), including the T6SS-5 protein VgrG5. However, the cellular-level mechanism of and T6SS-5 proteins important for bacteria-induced cell-cell fusion remained incompletely described. Using live-cell imaging, we found bacteria used actin-based motility to push on the host cell plasma membrane to form plasma membrane protrusions that extended into neighboring cells. Then, membrane fusion occurred within membrane protrusions either proximal to the bacterium at the tip or elsewhere within protrusions. Expression of VgrG5 by bacteria within membrane protrusions was required to promote cell-cell fusion. Furthermore, a second predicted T6SS-5 protein, TagD5, was also required for cell-cell fusion. In the absence of VgrG5 or TagD5, bacteria in plasma membrane protrusions were engulfed into neighboring cells. Our results suggest that the T6SS-5 effectors VgrG5 and TagD5 are secreted within membrane protrusions and act locally to promote membrane fusion.
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Affiliation(s)
- Nora Kostow
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Matthew D Welch
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720
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32
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Borgo GM, Burke TP, Tran CJ, Lo NTN, Engström P, Welch MD. A patatin-like phospholipase mediates Rickettsia parkeri escape from host membranes. Nat Commun 2022; 13:3656. [PMID: 35760786 PMCID: PMC9237051 DOI: 10.1038/s41467-022-31351-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 06/15/2022] [Indexed: 12/25/2022] Open
Abstract
Rickettsia species of the spotted fever group are arthropod-borne obligate intracellular bacteria that can cause mild to severe human disease. These bacteria invade host cells, replicate in the cell cytosol, and spread from cell to cell. To access the host cytosol and avoid immune detection, they escape membrane-bound vacuoles by expressing factors that disrupt host membranes. Here, we show that a patatin-like phospholipase A2 enzyme (Pat1) facilitates Rickettsia parkeri infection by promoting escape from host membranes and cell-cell spread. Pat1 is important for infection in a mouse model and, at the cellular level, is crucial for efficiently escaping from single and double membrane-bound vacuoles into the host cytosol, and for avoiding host galectins that mark damaged membranes. Pat1 is also important for avoiding host polyubiquitin, preventing recruitment of autophagy receptor p62, and promoting actin-based motility and cell-cell spread. Pathogenic Rickettsia species are arthropod-borne, obligate intracellular bacteria that invade host cells, replicate in the cell cytosol, and spread from cell to cell. Here, Borgo et al. identify a Rickettsia phospholipase enzyme that is important for infection by helping the bacteria escape from host cell vacuoles into the host cytosol, preventing targeting by autophagy, and promoting bacterial motility and spread to other cells.
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Affiliation(s)
- Gina M Borgo
- Division of Infectious Disease and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA, USA.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Thomas P Burke
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,Department of Microbiology & Molecular Genetics, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Cuong J Tran
- Division of Infectious Disease and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA, USA.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Nicholas T N Lo
- Division of Infectious Disease and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA, USA
| | - Patrik Engström
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,Primordial Genetics, San Diego, CA, USA
| | - Matthew D Welch
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
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33
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Hill NS, Welch MD. A glycine-rich PE_PGRS protein governs mycobacterial actin-based motility. Nat Commun 2022; 13:3608. [PMID: 35750685 PMCID: PMC9232537 DOI: 10.1038/s41467-022-31333-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 06/14/2022] [Indexed: 11/09/2022] Open
Abstract
Many key insights into actin regulation have been derived through examining how microbial pathogens intercept the actin cytoskeleton during infection. Mycobacterium marinum, a close relative of the human pathogen Mycobacterium tuberculosis, polymerizes host actin at the bacterial surface to drive intracellular movement and cell-to-cell spread during infection. However, the mycobacterial factor that commandeers actin polymerization has remained elusive. Here, we report the identification and characterization of the M. marinum actin-based motility factor designated mycobacterial intracellular rockets A (MirA), which is a member of the glycine-rich PE_PGRS protein family. MirA contains an amphipathic helix to anchor into the mycobacterial outer membrane and, surprisingly, also the surface of host lipid droplet organelles. MirA directly binds to and activates the host protein N-WASP to stimulate actin polymerization through the Arp2/3 complex, directing both bacterial and lipid droplet actin-based motility. MirA is dissimilar to known N-WASP activating ligands and may represent a new class of microbial and host actin regulator. Additionally, the MirA-N-WASP interaction represents a model to understand how the enigmatic PE_PGRS proteins contribute to mycobacterial pathogenesis.
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Affiliation(s)
- Norbert S Hill
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
| | - Matthew D Welch
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
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34
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Atwal S, Wongsantichon J, Giengkam S, Saharat K, Pittayasathornthun YJ, Chuenklin S, Wang LC, Chung T, Huh H, Lee SH, Sobota RM, Salje J. The obligate intracellular bacterium Orientia tsutsugamushi differentiates into a developmentally distinct extracellular state. Nat Commun 2022; 13:3603. [PMID: 35739103 PMCID: PMC9226355 DOI: 10.1038/s41467-022-31176-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 06/03/2022] [Indexed: 11/13/2022] Open
Abstract
Orientia tsutsugamushi (Ot) is an obligate intracellular bacterium in the family Rickettsiaceae that causes scrub typhus, a severe mite-borne human disease. Its mechanism of cell exit is unusual amongst Rickettsiaceae, as Ot buds off the surface of infected cells enveloped in plasma membrane. Here, we show that Ot bacteria that have budded out of host cells are in a distinct developmental stage compared with intracellular bacteria. We refer to these two stages as intracellular and extracellular bacteria (IB and EB, respectively). These two forms differ in physical properties: IB is both round and elongated, and EB is round. Additionally, IB has higher levels of peptidoglycan and is physically robust compared with EB. The two bacterial forms differentially express proteins involved in bacterial physiology and host-pathogen interactions, specifically those involved in bacterial dormancy and stress response, and outer membrane autotransporter proteins ScaA and ScaC. Whilst both populations are infectious, entry of IB Ot is sensitive to inhibitors of both clathrin-mediated endocytosis and macropinocytosis, whereas entry of EB Ot is only sensitive to a macropinocytosis inhibitor. Our identification and detailed characterization of two developmental forms of Ot significantly advances our understanding of the intracellular lifecycle of an important human pathogen. Orientia tsutsugamushi (Ot) the causing agent of scrub typhus exits infected cells using a unique mechanism that involves budding off the surface of infected cells. Here, Atwal et al. report that Ots that have budded from their host cells are in a distinct developmental stage than intracellular bacteria and provide the first characterization of this extracellular stage. Both forms are infectious but differ in their physical properties, proteome, and entry mechanism into host cells.
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Affiliation(s)
- Sharanjeet Atwal
- Public Health Research Institute, Rutgers the State University of New Jersey, Newark, NJ, USA
| | - Jantana Wongsantichon
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Suparat Giengkam
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kittirat Saharat
- Public Health Research Institute, Rutgers the State University of New Jersey, Newark, NJ, USA
| | | | - Suthida Chuenklin
- Public Health Research Institute, Rutgers the State University of New Jersey, Newark, NJ, USA.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Loo Chien Wang
- Functional Proteomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.,SingMass-National Mass Spectrometry Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Taerin Chung
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, USA
| | - Hyun Huh
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, USA
| | - Sang-Hyuk Lee
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, USA.,Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
| | - Radoslaw M Sobota
- Functional Proteomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.,SingMass-National Mass Spectrometry Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Jeanne Salje
- Public Health Research Institute, Rutgers the State University of New Jersey, Newark, NJ, USA. .,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
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35
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Aparicio-Yuste R, Muenkel M, Clark AG, Gómez-Benito MJ, Bastounis EE. A Stiff Extracellular Matrix Favors the Mechanical Cell Competition that Leads to Extrusion of Bacterially-Infected Epithelial Cells. Front Cell Dev Biol 2022; 10:912318. [PMID: 35813215 PMCID: PMC9257086 DOI: 10.3389/fcell.2022.912318] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 05/31/2022] [Indexed: 11/24/2022] Open
Abstract
Cell competition refers to the mechanism whereby less fit cells (“losers”) are sensed and eliminated by more fit neighboring cells (“winners”) and arises during many processes including intracellular bacterial infection. Extracellular matrix (ECM) stiffness can regulate important cellular functions, such as motility, by modulating the physical forces that cells transduce and could thus modulate the output of cellular competitions. Herein, we employ a computational model to investigate the previously overlooked role of ECM stiffness in modulating the forceful extrusion of infected “loser” cells by uninfected “winner” cells. We find that increasing ECM stiffness promotes the collective squeezing and subsequent extrusion of infected cells due to differential cell displacements and cellular force generation. Moreover, we discover that an increase in the ratio of uninfected to infected cell stiffness as well as a smaller infection focus size, independently promote squeezing of infected cells, and this phenomenon is more prominent on stiffer compared to softer matrices. Our experimental findings validate the computational predictions by demonstrating increased collective cell extrusion on stiff matrices and glass as opposed to softer matrices, which is associated with decreased bacterial spread in the basal cell monolayer in vitro. Collectively, our results suggest that ECM stiffness plays a major role in modulating the competition between infected and uninfected cells, with stiffer matrices promoting this battle through differential modulation of cell mechanics between the two cell populations.
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Affiliation(s)
- Raúl Aparicio-Yuste
- Department of Mechanical Engineering, Multiscale in Mechanical and Biological Engineering (M2BE), Instituto de Investigación en Ingeniería de Aragón (I3A), University of Zaragoza, Zaragoza, Spain
- Interfaculty Institute of Microbiology and Infection Medicine, Cluster of Excellence “Controlling Microbes to Fight Infections” (CMFI, EXC 2124), University of Tübingen, Tübingen, Germany
| | - Marie Muenkel
- Interfaculty Institute of Microbiology and Infection Medicine, Cluster of Excellence “Controlling Microbes to Fight Infections” (CMFI, EXC 2124), University of Tübingen, Tübingen, Germany
| | - Andrew G. Clark
- Institute of Cell Biology and Immunology/Stuttgart Research Center Systems Biology, University of Stuttgart, Stuttgart, Germany
- Center for Personalized Medicine, University of Tübingen, Tübingen, Germany
| | - María J. Gómez-Benito
- Department of Mechanical Engineering, Multiscale in Mechanical and Biological Engineering (M2BE), Instituto de Investigación en Ingeniería de Aragón (I3A), University of Zaragoza, Zaragoza, Spain
- *Correspondence: María J. Gómez-Benito, ; Effie E. Bastounis,
| | - Effie E. Bastounis
- Interfaculty Institute of Microbiology and Infection Medicine, Cluster of Excellence “Controlling Microbes to Fight Infections” (CMFI, EXC 2124), University of Tübingen, Tübingen, Germany
- *Correspondence: María J. Gómez-Benito, ; Effie E. Bastounis,
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36
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The Ankyrin Repeat Protein RARP-1 Is a Periplasmic Factor That Supports Rickettsia parkeri Growth and Host Cell Invasion. J Bacteriol 2022; 204:e0018222. [PMID: 35727033 DOI: 10.1128/jb.00182-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rickettsia spp. are obligate intracellular bacterial pathogens that have evolved a variety of strategies to exploit their host cell niche. However, the bacterial factors that contribute to this intracellular lifestyle are poorly understood. Here, we show that the conserved ankyrin repeat protein RARP-1 supports Rickettsia parkeri infection. Specifically, RARP-1 promotes efficient host cell entry and growth within the host cytoplasm, but it is not necessary for cell-to-cell spread or evasion of host autophagy. We further demonstrate that RARP-1 is not secreted into the host cytoplasm by R. parkeri. Instead, RARP-1 resides in the periplasm, and we identify several binding partners that are predicted to work in concert with RARP-1 during infection. Altogether, our data reveal that RARP-1 plays a critical role in the rickettsial life cycle. IMPORTANCE Rickettsia spp. are obligate intracellular bacterial pathogens that pose a growing threat to human health. Nevertheless, their strict reliance on a host cell niche has hindered investigation of the molecular mechanisms driving rickettsial infection. This study yields much-needed insight into the Rickettsia ankyrin repeat protein RARP-1, which is conserved across the genus but has not yet been functionally characterized. Earlier work had suggested that RARP-1 is secreted into the host cytoplasm. However, the results from this work demonstrate that R. parkeri RARP-1 resides in the periplasm and is important both for invasion of host cells and for growth in the host cell cytoplasm. These results reveal RARP-1 as a novel regulator of the rickettsial life cycle.
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Mechanical Forces Govern Interactions of Host Cells with Intracellular Bacterial Pathogens. Microbiol Mol Biol Rev 2022; 86:e0009420. [PMID: 35285720 PMCID: PMC9199418 DOI: 10.1128/mmbr.00094-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
To combat infectious diseases, it is important to understand how host cells interact with bacterial pathogens. Signals conveyed from pathogen to host, and vice versa, may be either chemical or mechanical. While the molecular and biochemical basis of host-pathogen interactions has been extensively explored, relatively less is known about mechanical signals and responses in the context of those interactions. Nevertheless, a wide variety of bacterial pathogens appear to have developed mechanisms to alter the cellular biomechanics of their hosts in order to promote their survival and dissemination, and in turn many host responses to infection rely on mechanical alterations in host cells and tissues to limit the spread of infection. In this review, we present recent findings on how mechanical forces generated by host cells can promote or obstruct the dissemination of intracellular bacterial pathogens. In addition, we discuss how in vivo extracellular mechanical signals influence interactions between host cells and intracellular bacterial pathogens. Examples of such signals include shear stresses caused by fluid flow over the surface of cells and variable stiffness of the extracellular matrix on which cells are anchored. We highlight bioengineering-inspired tools and techniques that can be used to measure host cell mechanics during infection. These allow for the interrogation of how mechanical signals can modulate infection alongside biochemical signals. We hope that this review will inspire the microbiology community to embrace those tools in future studies so that host cell biomechanics can be more readily explored in the context of infection studies.
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Scott AT, Vondrak CJ, Sanderlin AG, Lamason RL. Rickettsia parkeri. Trends Microbiol 2022; 30:511-512. [PMID: 35115187 PMCID: PMC11093278 DOI: 10.1016/j.tim.2022.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/07/2022] [Accepted: 01/10/2022] [Indexed: 10/19/2022]
Affiliation(s)
- Allison T Scott
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Cassandra J Vondrak
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA; Microbiology Graduate Program, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Allen G Sanderlin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Rebecca L Lamason
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA; Microbiology Graduate Program, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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Loyola S, Torre A, Flores-Mendoza C, Kocher C, Salmon-Mulanovich G, Richards AL, Leguia M. Molecular Characterization by Multilocus Sequence Typing and Diversity Analysis of Rickettsia asembonensis in Peru. Vector Borne Zoonotic Dis 2022; 22:170-177. [PMID: 35319919 PMCID: PMC8971995 DOI: 10.1089/vbz.2021.0077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Despite several reports worldwide documenting the presence of Rickettsia asembonensis in samples derived from ectoparasites, animals and more recently humans, genomic information of these specimens remains scarce, and when available, is usually limited to small genomic fragments of limited value. We generated complete sequences for two conserved (17-kDa antigen gene and gltA) and three variable (sca4, ompB and ompA) genes in five R. asembonensis DNA samples detected in cat and dog fleas in Peru. Complete gene sequences were used to conduct multi-locus sequence typing and phylogenetic analyses to assess diversity and infer relationships among strains and other reference sequences. The 17-kDa antigen gene was highly conserved across Rickettsia species. Of the variable genes ompB was the most variable, but this diversity was not captured through phylogenetics alone even when efforts were made to maximize potential diversity in terms of flea species, animal host and location. Through a combination of de novo and reference-based genome assembly we identified a 75 bp insertion in ompA that encodes a 25 aa repetitive motif found in other Rickettsia species, but not present in the original prototype strain from Kenya. R. asembonensis has only recently been shown to be a bona-fide human pathogen. As such, and compounded by a lack of available genomic information, it remains understudied. Our work directly addresses the lack of genomic information available worldwide for the study of these novel Rickettsia species and specifically contributes to our understanding of the diversity and molecular epidemiology of R. asembonensis in Peru.
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Affiliation(s)
- Steev Loyola
- Virology and Emerging Infections Department, U.S. Naval Medical Research Unit No. 6 (NAMRU-6), Lima, Peru.,Vysnova Partners, Maryland, Washington, USA
| | - Armando Torre
- Virology and Emerging Infections Department, U.S. Naval Medical Research Unit No. 6 (NAMRU-6), Lima, Peru.,Genomics Laboratory, Pontificia Universidad Católica del Perú (PUCP), Lima, Peru
| | - Carmen Flores-Mendoza
- Virology and Emerging Infections Department, U.S. Naval Medical Research Unit No. 6 (NAMRU-6), Lima, Peru
| | - Claudine Kocher
- Virology and Emerging Infections Department, U.S. Naval Medical Research Unit No. 6 (NAMRU-6), Lima, Peru
| | - Gabriela Salmon-Mulanovich
- Virology and Emerging Infections Department, U.S. Naval Medical Research Unit No. 6 (NAMRU-6), Lima, Peru.,Genomics Laboratory, Pontificia Universidad Católica del Perú (PUCP), Lima, Peru
| | - Allen L Richards
- Viral and Rickettsial Diseases Department, Naval Medical Research Center (NMRC), Silver Spring, Maryland, USA.,Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences (USUHS), Bethesda, Maryland, USA
| | - Mariana Leguia
- Virology and Emerging Infections Department, U.S. Naval Medical Research Unit No. 6 (NAMRU-6), Lima, Peru.,Genomics Laboratory, Pontificia Universidad Católica del Perú (PUCP), Lima, Peru
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Liu Y, Lu Y, Ning B, Su X, Yang B, Dong H, Yin B, Pang Z, Shen S. Intravenous Delivery of Living Listeria monocytogenes Elicits Gasdmermin-Dependent Tumor Pyroptosis and Motivates Anti-Tumor Immune Response. ACS NANO 2022; 16:4102-4115. [PMID: 35262333 DOI: 10.1021/acsnano.1c09818] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The facultative intracellular bacterium Listeria monocytogenes (Lmo) has great potential for development as a cancer vaccine platform given its properties. However, the clinical application of Lmo has been severely restricted due to its rapid clearance, compromised immune response in tumors, and inevitable side effects such as severe systemic inflammation after intravenous administration. Herein, an immunotherapy system was developed on the basis of natural red blood cell (RBC) membranes encapsulated Lmo with selective deletion of virulence factors (Lmo@RBC). The biomimetic Lmo@RBC not only generated a low systemic inflammatory response but also enhanced the accumulation in tumors due to the long blood circulation and tumor hypoxic microenvironment favoring anaerobic Lmo colonization. After genome screening of tumors treated with intravenous PBS, Lmo, or Lmo@RBC, it was first found that Lmo@RBC induced extensive pore-forming protein gasdermin C (GSDMC)-dependent pyroptosis, which reversed immunosuppressive tumor microenvironment and promoted a systemic strong and durable anti-tumor immune response, resulting in an excellent therapeutic effect on solid tumors and tumor metastasis. Overall, Lmo@RBC, as an intravenous living bacterial therapy for the selective initiation of tumor pyrolysis, provided a proof-of-concept of live bacteria vaccine potentiating tumor immune therapy.
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Affiliation(s)
- Yao Liu
- Key Laboratory of Spine and Spinal Cord Injury Repair, and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital. The Institute for Biomedical Engineering & Nano Science, Tongji University School of Medicine, Shanghai 200092, P. R. China
- Pharmacy Department & Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai 201399, China
| | - Yiping Lu
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Bo Ning
- Central laboratory, First Affiliated Hospital, Institute (college) of Integrative Medicine, Dalian Medical University, Dalian 116021, China
| | - Xiaomin Su
- Central laboratory, First Affiliated Hospital, Institute (college) of Integrative Medicine, Dalian Medical University, Dalian 116021, China
| | - Binru Yang
- State Key Laboratory of Molecular Engineering of Polymers & Department of Macromolecular Science, Fudan University, Shanghai, 200433, P. R. China
| | - Haiqing Dong
- Key Laboratory of Spine and Spinal Cord Injury Repair, and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital. The Institute for Biomedical Engineering & Nano Science, Tongji University School of Medicine, Shanghai 200092, P. R. China
| | - Bo Yin
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Zhiqing Pang
- School of Pharmacy & Key Laboratory of Smart Drug Delivery, Fudan University, Shanghai 201203, China
| | - Shun Shen
- Pharmacy Department & Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai 201399, China
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Yeh YT, Skinner DE, Criado-Hidalgo E, Chen NS, Garcia-De Herreros A, El-Sakkary N, Liu L, Zhang S, Kandasamy A, Chien S, Lasheras JC, del Álamo JC, Caffrey CR. Biomechanical interactions of Schistosoma mansoni eggs with vascular endothelial cells facilitate egg extravasation. PLoS Pathog 2022; 18:e1010309. [PMID: 35316298 PMCID: PMC8939816 DOI: 10.1371/journal.ppat.1010309] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 01/26/2022] [Indexed: 12/03/2022] Open
Abstract
The eggs of the parasitic blood fluke, Schistosoma, are the main drivers of the chronic pathologies associated with schistosomiasis, a disease of poverty afflicting approximately 220 million people worldwide. Eggs laid by Schistosoma mansoni in the bloodstream of the host are encapsulated by vascular endothelial cells (VECs), the first step in the migration of the egg from the blood stream into the lumen of the gut and eventual exit from the body. The biomechanics associated with encapsulation and extravasation of the egg are poorly understood. We demonstrate that S. mansoni eggs induce VECs to form two types of membrane extensions during encapsulation; filopodia that probe eggshell surfaces and intercellular nanotubes that presumably facilitate VEC communication. Encapsulation efficiency, the number of filopodia and intercellular nanotubes, and the length of these structures depend on the egg’s vitality and, to a lesser degree, its maturation state. During encapsulation, live eggs induce VEC contractility and membranous structures formation in a Rho/ROCK pathway-dependent manner. Using elastic hydrogels embedded with fluorescent microbeads as substrates to culture VECs, live eggs induce VECs to exert significantly greater contractile forces during encapsulation than dead eggs, which leads to 3D deformations on both the VEC monolayer and the flexible substrate underneath. These significant mechanical deformations cause the VEC monolayer tension to fluctuate with the eventual rupture of VEC junctions, thus facilitating egg transit out of the blood vessel. Overall, our data on the mechanical interplay between host VECs and the schistosome egg improve our understanding of how this parasite manipulates its immediate environment to maintain disease transmission. Schistosomiasis, which infects over 200 million people, is a painful disease of poverty that is caused by inflammatory responses to the Schistosoma blood fluke’s eggs. To continue the parasite’s life cycle, eggs must escape the blood vessels and migrate through tissues of the host to the alimentary canal for exit into the environment. The biomechanical processes that help the immobile eggs to cross the blood vessel’s vascular endothelial cells (VECs) as the first step in this migration are not understood. We found that live but not dead eggs induce VECs to crawl over and encapsulate them. VECs in contact with live eggs make membranous extensions (filopodia) to explore the egg’s surface and also form long intercellular nanotubes to communicate with neighboring cells. VECs stimulate particular (Rho/ROCK) biochemical pathways to increase cell contractility and the forces generated are large enough to eventually break the junctions between cells and allow passage of the eggs into the underlying tissue. Our findings show how schistosome eggs activate and interact with VECs to initiate their escape from the bloodstream.
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Affiliation(s)
- Yi-Ting Yeh
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California, United States of America
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California, United States of America
- * E-mail: (YTY); (JCdA); (CRC)
| | - Danielle E. Skinner
- Center for Discovery and Innovation in Parasitic Diseases (CDIPD), Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Ernesto Criado-Hidalgo
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California, United States of America
| | - Natalie Shee Chen
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Antoni Garcia-De Herreros
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California, United States of America
| | - Nelly El-Sakkary
- Center for Discovery and Innovation in Parasitic Diseases (CDIPD), Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Lawrence Liu
- Center for Discovery and Innovation in Parasitic Diseases (CDIPD), Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Shun Zhang
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California, United States of America
| | - Adithan Kandasamy
- Department of Mechanical Engineering, University of Washington, Seattle, Washington, United States of America
- Center for Cardiovascular Biology, University of Washington, Seattle Washington, United States of America
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle Washington, United States of America
| | - Shu Chien
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Juan C. Lasheras
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California, United States of America
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Juan C. del Álamo
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California, United States of America
- Department of Mechanical Engineering, University of Washington, Seattle, Washington, United States of America
- Center for Cardiovascular Biology, University of Washington, Seattle Washington, United States of America
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle Washington, United States of America
- * E-mail: (YTY); (JCdA); (CRC)
| | - Conor R. Caffrey
- Center for Discovery and Innovation in Parasitic Diseases (CDIPD), Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, United States of America
- * E-mail: (YTY); (JCdA); (CRC)
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Regulator of Actin-Based Motility (RoaM) Downregulates Actin Tail Formation by Rickettsia rickettsii and Is Negatively Selected in Mammalian Cell Culture. mBio 2022; 13:e0035322. [PMID: 35285700 PMCID: PMC9040884 DOI: 10.1128/mbio.00353-22] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The etiological agent of Rocky Mountain spotted fever, Rickettsia rickettsii, is an obligately intracellular pathogen that induces the polymerization of actin filaments to propel the bacterium through the cytoplasm and spread to new host cells. Cell-to-cell spread via actin-based motility is considered a key virulence determinant for spotted fever group rickettsiae, as interruption of sca2, the gene directly responsible for actin polymerization, has been shown to reduce fever in guinea pigs. However, little is known about how, or if, motility is regulated by the bacterium itself. We isolated a hyperspreading variant of R. rickettsii Sheila Smith that produces actin tails at an increased rate. A1G_06520 (roaM [regulator of actin-based motility]) was identified as a negative regulator of actin tail formation. Disruption of RoaM significantly increased the number of actin tails compared to the wild-type strain but did not increase virulence in guinea pigs; however, overexpression of RoaM dramatically decreased the presence of actin tails and moderated fever response. Localization experiments suggest that RoaM is not secreted, while reverse transcription-quantitative PCR (RT-qPCR) data show that various levels of RoaM do not significantly affect the expression of the known rickettsial actin-regulating proteins sca2, sca4, and rickA. Taken together, the data suggest a previously unrecognized level of regulation of actin-based motility in spotted fever group rickettsiae. Although this gene is intact in many isolates of spotted fever, transitional, and ancestral group Rickettsia spp., it is often ablated in highly passaged laboratory strains. Serial passage experiments revealed strong negative selection of roaM in Vero 76 cells.
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Köseoğlu VK, Jones MK, Agaisse H. The type 3 secretion effector IpgD promotes S. flexneri dissemination. PLoS Pathog 2022; 18:e1010324. [PMID: 35130324 PMCID: PMC8853559 DOI: 10.1371/journal.ppat.1010324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 02/17/2022] [Accepted: 01/31/2022] [Indexed: 12/15/2022] Open
Abstract
The bacterial pathogen Shigella flexneri causes 270 million cases of bacillary dysentery worldwide every year, resulting in more than 200,000 deaths. S. flexneri pathogenic properties rely on its ability to invade epithelial cells and spread from cell to cell within the colonic epithelium. This dissemination process relies on actin-based motility in the cytosol of infected cells and formation of membrane protrusions that project into adjacent cells and resolve into double-membrane vacuoles (DMVs) from which the pathogen escapes, thereby achieving cell-to-cell spread. S. flexneri dissemination is facilitated by the type 3 secretion system (T3SS) through poorly understood mechanisms. Here, we show that the T3SS effector IpgD facilitates the resolution of membrane protrusions into DMVs during S. flexneri dissemination. The phosphatidylinositol 4-phosphatase activity of IpgD decreases PtdIns(4,5)P2 levels in membrane protrusions, thereby counteracting de novo cortical actin formation in protrusions, a process that restricts the resolution of protrusions into DMVs. Finally, using an infant rabbit model of shigellosis, we show that IpgD is required for efficient cell-to-cell spread in vivo and contributes to the severity of dysentery. The intracellular pathogen Shigella flexneri is the causative agent of bacillary dysentery (blood in stool). Invasion of epithelial cells and cell-to-cell spread are critical determinants of S. flexneri pathogenesis. Cell-to-cell spread relies on the formation of membrane protrusions that project into adjacent cells and resolve into vacuoles. The molecular mechanisms supporting this dissemination process are poorly understood. In this study, we show that S. flexneri employs the phosphatidylinositol phosphatase activity of the T3SS effector protein IpgD to manipulate phosphoinositides in the protrusion membrane. Manipulation of phosphoinositide signaling restricts the formation of actin networks underneath the protrusion membrane, which would otherwise prevent the scission of protrusions into vacuoles. We also demonstrate that IpgD is required for efficient dissemination in the colon of infant rabbits and contributes to the severity of disease. This study exemplifies how manipulation of phosphoinositide signaling by intracellular pathogens supports bacterial pathogenesis.
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Affiliation(s)
- Volkan K. Köseoğlu
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia, United States of America
| | - Marieke K. Jones
- Claude Moore Health Sciences Library, University of Virginia, Charlottesville, Virginia, United States of America
| | - Hervé Agaisse
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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Ireton K, Mortuza R, Gyanwali GC, Gianfelice A, Hussain M. Role of internalin proteins in the pathogenesis of Listeria monocytogenes. Mol Microbiol 2021; 116:1407-1419. [PMID: 34704304 DOI: 10.1111/mmi.14836] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 12/15/2022]
Abstract
Listeria monocytogenes is a food-borne bacterium that causes gastroenteritis, meningitis, or abortion. L. monocytogenes induces its internalization (entry) into human cells and either spreads laterally in tissues or transcytoses to traverse anatomical barriers. In this review, we discuss mechanisms by which five structurally related proteins of the "internalin" family of L. monocytogenes (InlA, InlB, InlC, InlF, and InlP) interact with distinct host receptors to promote infection of human cells and/or crossing of the intestinal, blood-brain, or placental barriers. We focus on recent results demonstrating that the internalin proteins InlA, InlB, and InlC exploit exocytic pathways to stimulate transcytosis, entry, or cell-to-cell spread, respectively. We also discuss evidence that InlA-mediated transcytosis contributes to traversal of the intestinal barrier, whereas InlF promotes entry into endothelial cells to breach the blood-brain barrier. InlB also facilitates the crossing of the blood-brain barrier, but does so by extending the longevity of infected monocytes that may subsequently act as a "Trojan horse" to transfer bacteria to the brain. InlA, InlB, and InlP each contribute to fetoplacental infection by targeting syncytiotrophoblast or cytotrophoblast layers of the placenta. This work highlights the diverse functions of internalins and the complex mechanisms by which these structurally related proteins contribute to disease.
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Affiliation(s)
- Keith Ireton
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Roman Mortuza
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | | | - Antonella Gianfelice
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Mazhar Hussain
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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Host EPAC1 Modulates Rickettsial Adhesion to Vascular Endothelial Cells via Regulation of ANXA2 Y23 Phosphorylation. Pathogens 2021; 10:pathogens10101307. [PMID: 34684255 PMCID: PMC8537355 DOI: 10.3390/pathogens10101307] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/06/2021] [Accepted: 10/10/2021] [Indexed: 01/27/2023] Open
Abstract
Introduction: Intracellular cAMP receptor exchange proteins directly activated by cAMP 1 (EPAC1) regulate obligate intracellular parasitic bacterium rickettsial adherence to and invasion into vascular endothelial cells (ECs). However, underlying precise mechanism(s) remain unclear. The aim of the study is to dissect the functional role of the EPAC1-ANXA2 signaling pathway during initial adhesion of rickettsiae to EC surfaces. Methods: In the present study, an established system that is anatomically based and quantifies bacterial adhesion to ECs in vivo was combined with novel fluidic force microscopy (FluidFM) to dissect the functional role of the EPAC1-ANXA2 signaling pathway in rickettsiae–EC adhesion. Results: The deletion of the EPAC1 gene impedes rickettsial binding to endothelium in vivo. Rickettsial OmpB shows a host EPAC1-dependent binding strength on the surface of a living brain microvascular EC (BMEC). Furthermore, ectopic expression of phosphodefective and phosphomimic mutants replacing tyrosine (Y) 23 of ANXA2 in ANXA2-knock out BMECs results in different binding force to reOmpB in response to the activation of EPAC1. Conclusions: EPAC1 modulates rickettsial adhesion, in association with Y23 phosphorylation of the binding receptor ANXA2. Underlying mechanism(s) should be further explored to delineate the accurate role of cAMP-EPAC system during rickettsial infection.
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Liu X, Zhu K, Duan X, Wang P, Han Y, Peng W, Huang J. Extracellular matrix stiffness modulates host-bacteria interactions and antibiotic therapy of bacterial internalization. Biomaterials 2021; 277:121098. [PMID: 34478931 DOI: 10.1016/j.biomaterials.2021.121098] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 05/12/2021] [Accepted: 08/24/2021] [Indexed: 02/04/2023]
Abstract
Pathogenic bacteria evolve multiple strategies to hijack host cells for intracellular survival and persistent infections. Previous studies have revealed the intricate interactions between bacteria and host cells at genetic, biochemical and even single molecular levels. Mechanical interactions and mechanotransduction exert a crucial impact on the behaviors and functions of pathogenic bacteria and host cells, owing to the ubiquitous mechanical microenvironments like extracellular matrix (ECM) stiffness. Nevertheless, it remains unclear whether and how ECM stiffness modulates bacterial infections and the sequential outcome of antibacterial therapy. Here we show that bacteria tend to adhere to and invade epithelial cells located on the regions with relatively high traction forces. ECM stiffness regulates spatial distributions of bacteria during the invasion through arrangements of F-actin cytoskeletons in host cells. Depolymerization of cytoskeletons in the host cells induced by bacterial infection decreases intracellular accumulation of antibiotics, thus preventing the eradication of invaded bacterial pathogens. These findings not only reveal the key regulatory role of ECM stiffness, but suggest that the coordination of cytoskeletons may provide alternative approaches to improve antibiotic therapy against multidrug resistant bacteria in clinic.
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Affiliation(s)
- Xiaoye Liu
- Department of Mechanics and Engineering Science, College of Engineering, Academy for Advanced Interdisciplinary Studies, and Beijing Innovation Center for Engineering Science and Advanced Technology, College of Engineering, Peking University, Beijing, 100871, China; College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Kui Zhu
- College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Xiaocen Duan
- Department of Mechanics and Engineering Science, College of Engineering, Academy for Advanced Interdisciplinary Studies, and Beijing Innovation Center for Engineering Science and Advanced Technology, College of Engineering, Peking University, Beijing, 100871, China
| | - Pudi Wang
- Department of Mechanics and Engineering Science, College of Engineering, Academy for Advanced Interdisciplinary Studies, and Beijing Innovation Center for Engineering Science and Advanced Technology, College of Engineering, Peking University, Beijing, 100871, China
| | - Yiming Han
- Department of Mechanics and Engineering Science, College of Engineering, Academy for Advanced Interdisciplinary Studies, and Beijing Innovation Center for Engineering Science and Advanced Technology, College of Engineering, Peking University, Beijing, 100871, China
| | - Wenjing Peng
- College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Jianyong Huang
- Department of Mechanics and Engineering Science, College of Engineering, Academy for Advanced Interdisciplinary Studies, and Beijing Innovation Center for Engineering Science and Advanced Technology, College of Engineering, Peking University, Beijing, 100871, China.
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Rauch J, Barton J, Kwiatkowski M, Wunderlich M, Steffen P, Moderzynski K, Papp S, Höhn K, Schwanke H, Witt S, Richardt U, Mehlhoop U, Schlüter H, Pianka V, Fleischer B, Tappe D, Osterloh A. GroEL is an immunodominant surface-exposed antigen of Rickettsia typhi. PLoS One 2021; 16:e0253084. [PMID: 34111210 PMCID: PMC8191997 DOI: 10.1371/journal.pone.0253084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/28/2021] [Indexed: 11/26/2022] Open
Abstract
Rickettsioses are neglected and emerging potentially fatal febrile diseases that are caused by obligate intracellular bacteria, rickettsiae. Rickettsia (R.) typhi and R. prowazekii constitute the typhus group (TG) of rickettsiae and are the causative agents of endemic and epidemic typhus, respectively. We recently generated a monoclonal antibody (BNI52) against R. typhi. Characterization of BNI52 revealed that it specifically recognizes TG rickettsiae but not the members of the spotted fever group (SFG) rickettsiae. We further show that BNI52 binds to protein fragments of ±30 kDa that are exposed on the bacterial surface and also present in the periplasmic space. These protein fragments apparently derive from the cytosolic GroEL protein of R. typhi and are also recognized by antibodies in the sera from patients and infected mice. Furthermore, BNI52 opsonizes the bacteria for the uptake by antigen presenting cells (APC), indicating a contribution of GroEL-specific antibodies to protective immunity. Finally, it is interesting that the GroEL protein belongs to 32 proteins that are differentially downregulated by R. typhi after passage through immunodeficient BALB/c CB17 SCID mice. This could be a hint that the rickettsia GroEL protein may have immunomodulatory properties as shown for the homologous protein from several other bacteria, too. Overall, the results of this study provide evidence that GroEL represents an immunodominant antigen of TG rickettsiae that is recognized by the humoral immune response against these pathogens and that may be interesting as a vaccine candidate. Apart from that, the BNI52 antibody represents a new tool for specific detection of TG rickettsiae in various diagnostic and experimental setups.
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Affiliation(s)
- Jessica Rauch
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Jessica Barton
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Malte Wunderlich
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Pascal Steffen
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Stefanie Papp
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Katharina Höhn
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Hella Schwanke
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Susanne Witt
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ulricke Richardt
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ute Mehlhoop
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Verena Pianka
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Dennis Tappe
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Anke Osterloh
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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Engström P, Burke TP, Tran CJ, Iavarone AT, Welch MD. Lysine methylation shields an intracellular pathogen from ubiquitylation and autophagy. SCIENCE ADVANCES 2021; 7:eabg2517. [PMID: 34172444 PMCID: PMC8232902 DOI: 10.1126/sciadv.abg2517] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 05/12/2021] [Indexed: 05/05/2023]
Abstract
Many intracellular pathogens avoid detection by their host cells. However, it remains unknown how they avoid being tagged by ubiquitin, an initial step leading to antimicrobial autophagy. Here, we show that the intracellular bacterial pathogen Rickettsia parkeri uses two protein-lysine methyltransferases (PKMTs) to modify outer membrane proteins (OMPs) and prevent their ubiquitylation. Mutants deficient in the PKMTs were avirulent in mice and failed to grow in macrophages because of ubiquitylation and autophagic targeting. Lysine methylation protected the abundant surface protein OmpB from ubiquitin-dependent depletion from the bacterial surface. Analysis of the lysine-methylome revealed that PKMTs modify a subset of OMPs, including OmpB, by methylation at the same sites that are modified by host ubiquitin. These findings show that lysine methylation is an essential determinant of rickettsial pathogenesis that shields bacterial proteins from ubiquitylation to evade autophagic targeting.
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Affiliation(s)
- Patrik Engström
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Thomas P Burke
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Cuong J Tran
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Anthony T Iavarone
- QB3/Chemistry Mass Spectrometry Facility, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Matthew D Welch
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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Bastounis EE, Radhakrishnan P, Prinz CK, Theriot JA. Volume measurement and biophysical characterization of mounds in epithelial monolayers after intracellular bacterial infection. STAR Protoc 2021; 2:100551. [PMID: 34095865 PMCID: PMC8165451 DOI: 10.1016/j.xpro.2021.100551] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Mechanical forces are important in (patho)physiological processes, including how host epithelial cells interact with intracellular bacterial pathogens. As these pathogens disseminate within host epithelial monolayers, large mounds of infected cells are formed due to the forceful action of surrounding uninfected cells, limiting bacterial spread across the basal cell monolayer. Here, we present a protocol for mound volume measurement and biophysical characterization of mound formation. Modifications to this protocol may be necessary for studying different host cell types or pathogenic organisms. For complete details on the use and execution of this protocol, please refer to Bastounis et al. (2021). Protocol allows for formation of mounds of extruded infected cells in cell monolayers Confocal microscopy and image processing to calculate volume of extruded domains Laser wounding protocol for tension estimation built around mounds TFM incorporated to measure traction stresses of infected mounders and surrounders
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Affiliation(s)
- Effie E Bastounis
- Department of Biology and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA.,Interfaculty Institute of Microbiology and Infection Medicine, Cluster of Excellence "Controlling Microbes to Fight Infections" (CMFI, EXC 2124), University of Tübingen, Tübingen 72074, Germany
| | - Prathima Radhakrishnan
- Department of Biology and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA.,Biophysics Program, Stanford University, Stanford, CA 94305, USA
| | - Christopher K Prinz
- Department of Biology and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| | - Julie A Theriot
- Department of Biology and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
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50
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Abstract
Spotted fever group rickettsioses (SFRs) are devastating human infections. Vascular endothelial cells (ECs) are the primary targets of rickettsial infection. Edema resulting from EC barrier dysfunction occurs in the brain and lungs in most cases of lethal SFR, but the underlying mechanisms remain unclear. The aim of the study was to explore the potential role of Rickettsia-infected, EC-derived exosomes (Exos) during infection. Using size exclusion chromatography (SEC), we purified Exos from conditioned, filtered, bacterium-free media collected from Rickettsia parkeri-infected human umbilical vein ECs (HUVECs) (R-ECExos) and plasma of Rickettsia australis- or R. parkeri-infected mice (R-plsExos). We observed that rickettsial infection increased the release of heterogeneous plsExos, but endothelial exosomal size, morphology, and production were not significantly altered following infection. Compared to normal plsExos and ECExos, both R-plsExos and R-ECExos induced dysfunction of recipient normal brain microvascular ECs (BMECs). The effect of R-plsExos on mouse recipient BMEC barrier function is dose dependent. The effect of R-ECExos on human recipient BMEC barrier function is dependent on the exosomal RNA cargo. Next-generation sequencing analysis and stem-loop quantitative reverse transcription-PCR (RT-qPCR) validation revealed that rickettsial infection triggered the selective enrichment of endothelial exosomal mir-23a and mir-30b, which potentially target the endothelial barrier. To our knowledge, this is the first report on the functional role of extracellular vesicles following infection by obligately intracellular bacteria.
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