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Bourgeois JS, Hu LT. Hitchhiker's Guide to Borrelia burgdorferi. J Bacteriol 2024; 206:e0011624. [PMID: 39140751 PMCID: PMC11411949 DOI: 10.1128/jb.00116-24] [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] [Indexed: 08/15/2024] Open
Abstract
Don't Panic. In the nearly 50 years since the discovery of Lyme disease, Borrelia burgdorferi has emerged as an unlikely workhorse of microbiology. Interest in studying host-pathogen interactions fueled significant progress in making the fastidious microbe approachable in laboratory settings, including the development of culture methods, animal models, and genetic tools. By developing these systems, insight has been gained into how the microbe is able to survive its enzootic cycle and cause human disease. Here, we discuss the discovery of B. burgdorferi and its development as a model organism before diving into the critical lessons we have learned about B. burgdorferi biology at pivotal stages of its lifecycle: gene expression changes during the tick blood meal, colonization of a new vertebrate host, and developing a long-lasting infection in that vertebrate until a new tick feeds. Our goal is to highlight the advancements that have facilitated B. burgdorferi research and identify gaps in our current understanding of the microbe.
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Affiliation(s)
- Jeffrey S Bourgeois
- Department of Molecular Biology and Microbiology, Tufts University Lyme Disease Initiative, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Linden T Hu
- Department of Molecular Biology and Microbiology, Tufts University Lyme Disease Initiative, Tufts University School of Medicine, Boston, Massachusetts, USA
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2
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Raghunandanan S, Priya R, Lin G, Alanazi F, Zoss A, Warren E, Yang XF. Positive feedback regulation between RpoS and BosR in the Lyme disease pathogen. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.14.613071. [PMID: 39314342 PMCID: PMC11419129 DOI: 10.1101/2024.09.14.613071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
In Borrelia burgdorferi , the Lyme disease pathogen, differential gene expression is primarily controlled by the alternative sigma factor RpoS (σ S ). Understanding how RpoS levels are regulated is crucial for elucidating how B. burgdorferi is maintained throughout its enzootic cycle. Our recent studies have shown that a homolog of Fur/PerR repressor/activator, BosR, functions as an RNA-binding protein that controls the rpoS mRNA stability. However, the mechanisms of regulation of BosR, particularly in response to host signals and environmental cues, remain largely unclear. In this study, we revealed a positive feedback loop between RpoS and BosR, where RpoS post-transcriptionally regulates BosR levels. Specifically, mutation or deletion of rpoS significantly reduced BosR levels, while artificial induction of rpoS resulted in a dose-dependent increase in BosR levels. Notably, RpoS does not affect bosR mRNA levels but instead modulates the turnover rate of the BosR protein. Furthermore, we demonstrated that environmental cues do not directly influence bosR expression but instead induce rpoS transcription and RpoS production, thereby enhancing BosR protein levels. This discovery adds a new layer of complexity to the RpoN-RpoS pathway and suggests the need to re-evaluate the factors and signals previously believed to regulate RpoS levels through BosR. IMPORTANCE Lyme disease is the most prevalent arthropod-borne infection in the United States. The etiological agent, Borreliella (or Borrelia ) burgdorferi , is maintained in nature through an enzootic cycle involving a tick vector and a mammalian host. RpoS, the master regulator of differential gene expression, plays a crucial role in tick transmission and mammalian infection of B. burgdorferi . This study reveals a positive feedback loop between RpoS and a Fur/PerR homolog. Elucidating this regulatory network is essential for identifying potential therapeutic targets to disrupt B. burgdorferi 's enzootic cycle. The findings also have broader implications for understanding the regulation of RpoS and Fur/PerR family in other bacteria.
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Alvarez-Olmedo D, Kamaliddin C, Verhey TB, Ho M, DeVinney R, Chaconas G. Transendothelial migration of the Lyme disease spirochete involves spirochete internalization as an intermediate step through a transcellular pathway that involves Cdc42 and Rac1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.10.612329. [PMID: 39314306 PMCID: PMC11419014 DOI: 10.1101/2024.09.10.612329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Despite its importance in pathogenesis, the hematogenous dissemination pathway of B. burgdorferi is still largely uncharacterized. To probe the molecular details of transendothelial migration more easily, we studied this process using cultured primary or telomerase-immortalized human microvascular endothelial cells in a medium that maintains both the human cells and the spirochetes. In B. burgdorferi infected monolayers we observed ∼55% of wild-type spirochetes crossing the monolayer. Microscopic characterization revealed entrance points across the cellular surface rather than at cellular junctions, supporting a transcellular route. In support of this pathway, locking the endothelial junctions using a VE-PTP inhibitor did not reduce transendothelial migration. We also used inhibitors to block the most common endocytic pathways to elucidate effectors that might be involved in B. burgdorferi uptake and/or transmigration. Directly inhibiting Cdc42 reduced spirochete transmigration by impeding internalization. However, blocking Rac1 alone dramatically reduced transmigration and resulted in a concomitant increase in spirochete accumulation in the cell. Our combined results support that B. burgdorferi internalization is an intermediate step in the transendothelial migration process which requires both Cdc42 and Rac1; Cdc42 is needed for spirochete internalization while Rac1 is required for cellular egress. These are the first two host proteins implicated in B. burgdorferi transmigration across endothelial cells. IMPORTANCE Lyme borreliosis is caused by Borrelia burgdorferi and related bacteria. It is the most common tick-transmitted illness in the Northern Hemisphere. The ability of this pathogen to spread to a wide variety of locations results in a diverse set of clinical manisfestations, yet little is known regarding vascular escape of the spirochete, an important pathway for dissemination. Our current work has studied the traversal of B. burgdorferi across a monolayer of microvascular endothelial cells grown in culture. We show that this occurs by passage of the spirochetes directly through these cells rather than at cellular junctions and that internalization of B. burgdorferi is an intermediate step in the transmigration process. We also identify the first two host proteins, Cdc42 and Rac1, that are used by the spirochetes to promote traversal of the cellular monolayer. Our new experimental system also provides a new avenue for further studies of this important process.
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Jackson-Litteken CD, Guo W, Hogland BA, Ratliff CT, McFadden L, Fullerton MS, Voth DE, Rego ROM, Blevins JS. Development and validation of systems for genetic manipulation of the Old World tick-borne relapsing fever spirochete, Borrelia duttonii. PLoS Negl Trop Dis 2024; 18:e0012348. [PMID: 39038047 PMCID: PMC11293673 DOI: 10.1371/journal.pntd.0012348] [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: 05/28/2024] [Revised: 08/01/2024] [Accepted: 07/08/2024] [Indexed: 07/24/2024] Open
Abstract
Relapsing fever (RF), a vector-borne disease caused by Borrelia spp., is characterized by recurring febrile episodes due to repeated bouts of bacteremia. RF spirochetes can be geographically and phylogenetically divided into two distinct groups; Old World RF Borrelia (found in Africa, Asia, and Europe) and New World RF Borrelia (found in the Americas). While RF is a rarely reported disease in the Americas, RF is prevalent in endemic parts of Africa. Despite phylogenetic differences between Old World and New World RF Borrelia and higher incidence of disease associated with Old World RF spirochete infection, genetic manipulation has only been described in New World RF bacteria. Herein, we report the generation of genetic tools for use in the Old World RF spirochete, Borrelia duttonii. We describe methods for transformation and establish shuttle vector- and integration-based approaches for genetic complementation, creating green fluorescent protein (gfp)-expressing B. duttonii strains as a proof of principle. Allelic exchange mutagenesis was also used to inactivate a homolog of the Borrelia burgdorferi p66 gene, which encodes an important virulence factor, in B. duttonii and demonstrate that this mutant was attenuated in a murine model of RF. Finally, the B. duttonii p66 mutant was complemented using shuttle vector- and cis integration-based approaches. As expected, complemented p66 mutant strains were fully infectious, confirming that P66 is required for optimal mammalian infection. The genetic tools and techniques reported herein represent an important advancement in the study of RF Borrelia that allows for future characterization of virulence determinants and colonization factors important for the enzootic cycle of Old World RF spirochetes.
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Affiliation(s)
- Clay D. Jackson-Litteken
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Wanfeng Guo
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Brandon A. Hogland
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - C. Tyler Ratliff
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - LeAnn McFadden
- Department of Biology, University of Arkansas at Little Rock, Little Rock, Arkansas, United States of America
| | - Marissa S. Fullerton
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Daniel E. Voth
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Ryan O. M. Rego
- Institute of Parasitology, Biology Centre CAS, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Jon S. Blevins
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
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Yamasaki Y, Singh P, Vimonish R, Ueti M, Bankhead T. Development and Application of an In Vitro Tick Feeding System to Identify Ixodes Tick Environment-Induced Genes of the Lyme Disease Agent, Borrelia burgdorferi. Pathogens 2024; 13:487. [PMID: 38921785 PMCID: PMC11207009 DOI: 10.3390/pathogens13060487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 06/27/2024] Open
Abstract
The bacterial agent of Lyme disease, Borrelia burgdorferi, exists in an enzootic cycle by adapting to dissimilar mammalian and tick environments. The genetic elements necessary for host and vector adaptation are spread across a bacterial genome comprised of a linear chromosome and essential linear and circular plasmids. The promoter trap system, In Vivo Expression Technology (IVET), has been used to identify promoters of B. burgdorferi that are transcriptionally active specifically during infection of a murine host. However, an observed infection bottleneck effect in mice prevented the application of this system to study promoters induced in a tick environment. In this study, we adapted a membrane-based in vitro feeding system as a novel method to infect the Ixodes spp. vector with B. burgdorferi. Once adapted, we performed IVET screens as a proof of principle via an infected bloodmeal on the system. The screen yielded B. burgdorferi promoters that are induced during tick infection and verified relative expression levels using qRT-PCR. The results of our study demonstrate the potential of our developed in vitro tick feeding system and IVET systems to gain insight into the adaptive gene expression of the Lyme disease bacteria to the tick vector.
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Affiliation(s)
- Youki Yamasaki
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA; (Y.Y.); (P.S.); (R.V.)
| | - Preeti Singh
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA; (Y.Y.); (P.S.); (R.V.)
| | - Rubikah Vimonish
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA; (Y.Y.); (P.S.); (R.V.)
| | - Massaro Ueti
- Animal Disease Research Unit, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Pullman, WA 99164, USA;
| | - Troy Bankhead
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA; (Y.Y.); (P.S.); (R.V.)
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Alanazi F, Raghunandanan S, Priya R, Yang XF. The Rrp2-RpoN-RpoS pathway plays an important role in the blood-brain barrier transmigration of the Lyme disease pathogen. Infect Immun 2023; 91:e0022723. [PMID: 37874144 PMCID: PMC10652863 DOI: 10.1128/iai.00227-23] [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: 06/13/2023] [Accepted: 09/14/2023] [Indexed: 10/25/2023] Open
Abstract
Lyme disease, caused by Borrelia (or Borreliella) burgdorferi, is a complex multisystemic disorder that includes Lyme neuroborreliosis resulting from the invasion of both the central and peripheral nervous systems. However, factors that enable the pathogen to cross the blood-brain barrier (BBB) and invade the central nervous system (CNS) are still not well understood. The objective of this study was to identify the B. burgdorferi factors required for BBB transmigration. We utilized a transwell BBB model based on human brain-microvascular endothelial cells and focused on investigating the Rrp2-RpoN-RpoS pathway, a central regulatory pathway that is essential for mammalian infection by B. burgdorferi. Our results demonstrated that the Rrp2-RpoN-RpoS pathway is crucial for BBB transmigration. Furthermore, we identified OspC, a major surface lipoprotein controlled by the Rrp2-RpoN-RpoS pathway, as a significant contributor to BBB transmigration. Constitutive production of OspC in a mutant defective in the Rrp2-RpoN-RpoS pathway did not rescue the impairment in BBB transmigration, indicating that this pathway controls additional factors for this process. Two other major surface lipoproteins controlled by this pathway, DbpA/B and BBK32, appeared to be dispensable for BBB transmigration. In addition, both the surface lipoprotein OspA and the Rrp1 pathway, which are required B. burgdorferi colonization in the tick vector, were found not required for BBB transmigration. Collectively, our findings using in vitro transwell assays uncover another potential role of the Rrp2-RpoN-RpoS pathway in BBB transmigration of B. burgdorferi and invasion into the CNS.
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Affiliation(s)
- Fuad Alanazi
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Sajith Raghunandanan
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Raj Priya
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - X. Frank Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Reddy PJ, Sun Z, Wippel HH, Baxter D, Swearingen K, Shteynberg DD, Midha MK, Caimano MJ, Strle K, Choi Y, Chan AP, Schork NJ, Moritz RL. Borrelia PeptideAtlas: A proteome resource of common Borrelia burgdorferi isolates for Lyme research. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.16.545244. [PMID: 37398146 PMCID: PMC10312716 DOI: 10.1101/2023.06.16.545244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Lyme disease, caused by an infection with the spirochete Borrelia burgdorferi, is the most common vector-borne disease in North America. B. burgdorferi strains harbor extensive genomic and proteomic variability and further comparison is key to understanding the spirochetes infectivity and biological impacts of identified sequence variants. To achieve this goal, both transcript and mass spectrometry (MS)-based proteomics was applied to assemble peptide datasets of laboratory strains B31, MM1, B31-ML23, infective isolates B31-5A4, B31-A3, and 297, and other public datasets, to provide a publicly available Borrelia PeptideAtlas http://www.peptideatlas.org/builds/borrelia/. Included is information on total proteome, secretome, and membrane proteome of these B. burgdorferi strains. Proteomic data collected from 35 different experiment datasets, with a total of 855 mass spectrometry runs, identified 76,936 distinct peptides at a 0.1% peptide false-discovery-rate, which map to 1,221 canonical proteins (924 core canonical and 297 noncore canonical) and covers 86% of the total base B31 proteome. The diverse proteomic information from multiple isolates with credible data presented by the Borrelia PeptideAtlas can be useful to pinpoint potential protein targets which are common to infective isolates and may be key in the infection process.
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Affiliation(s)
| | - Zhi Sun
- Institute for Systems Biology, Seattle, Washington, USA
| | | | - David Baxter
- Institute for Systems Biology, Seattle, Washington, USA
| | | | | | | | | | - Klemen Strle
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Yongwook Choi
- Translational Genomics Research Institute, Phoenix, Arizona, USA
| | - Agnes P. Chan
- Translational Genomics Research Institute, Phoenix, Arizona, USA
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Kasumba IN, Tilly K, Lin T, Norris SJ, Rosa PA. Strict Conservation yet Non-Essential Nature of Plasmid Gene bba40 in the Lyme Disease Spirochete Borrelia burgdorferi. Microbiol Spectr 2023; 11:e0047723. [PMID: 37010416 PMCID: PMC10269632 DOI: 10.1128/spectrum.00477-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/10/2023] [Indexed: 04/04/2023] Open
Abstract
The highly segmented genome of Borrelia burgdorferi, the tick-borne bacterium that causes Lyme disease, is composed of a linear chromosome and more than 20 co-existing endogenous plasmids. Many plasmid-borne genes are unique to B. burgdorferi and some have been shown to provide essential functions at discrete points of the infectious cycle between a tick vector and rodent host. In this study, we investigated the role of bba40, a highly conserved and differentially expressed gene on a ubiquitous linear plasmid of B. burgdorferi. In a prior genome-wide analysis, inactivation of bba40 by transposon insertion was linked with a noninfectious phenotype in mice, suggesting that conservation of the gene in the Lyme disease spirochete reflected a critical function of the encoded protein. To address this hypothesis, we moved the bba40::Tn allele into a similar wild-type background and compared the phenotypes of isogenic wild-type, mutant and complemented strains in vitro and throughout the in vivo mouse/tick infectious cycle. In contrast to the previous study, we identified no defect in the ability of the bba40 mutant to colonize the tick vector or murine host, or to be efficiently transmitted between them. We conclude that bba40 joins a growing list of unique, highly conserved, yet fully dispensable plasmid-borne genes of the Lyme disease spirochete. We infer that the experimental infectious cycle, while including the tick vector and murine host, lacks key selective forces imposed during the natural enzootic cycle. IMPORTANCE The key finding of this study contradicts our premise that the ubiquitous presence and strict sequence conservation of a unique gene in the Lyme disease spirochete, Borrelia burgdorferi, reflect a critical role in either the murine host or tick vector in which these bacteria are maintained in nature. Instead, the outcome of this investigation illustrates the inadequate nature of the experimental infectious cycle currently employed in the laboratory to fully model the enzootic cycle of the Lyme disease spirochete. This study also highlights the importance of complementation for accurate interpretation of mutant phenotypes in genetic studies of Borrelia burgdorferi.
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Affiliation(s)
- Irene N. Kasumba
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Kit Tilly
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Tao Lin
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, Houston, Texas, USA
| | - Steven J. Norris
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, Houston, Texas, USA
| | - Patricia A. Rosa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
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Casselli T, Tourand Y, Gura K, Stevenson B, Zückert WR, Brissette CA. Endogenous Linear Plasmids lp28-4 and lp25 Are Required for Infectivity and Restriction Protection in the Lyme Disease Spirochete Borrelia mayonii. Infect Immun 2023; 91:e0006123. [PMID: 36853005 PMCID: PMC10016076 DOI: 10.1128/iai.00061-23] [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: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 03/01/2023] Open
Abstract
Borrelia mayonii is a newly recognized causative agent of Lyme disease in the Upper Midwestern United States, with distinct clinical presentations compared to classical Lyme disease caused by other Lyme Borrelia species. However, little is known about the B. mayonii genetic determinants required for establishing infection or perpetuating disease in mammals. Extrachromosomal plasmids in Borrelia species often encode proteins necessary for infection and pathogenesis, and spontaneous loss of these plasmids can lead to the identification of virulence determinant genes. Here, we describe infection of Lyme disease-susceptible C3H mice with B. mayonii, and show bacterial dissemination and persistence in peripheral tissues. Loss of endogenous plasmids, including lp28-4, lp25, and lp36 correlated with reduced infectivity in mice. The apparent requirement for lp28-4 during murine infection suggests the presence of a novel virulence determinant, as this plasmid does not encode homologs of any known virulence determinant. We also describe transformation and stable maintenance of a self-replicating shuttle vector in B. mayonii, and show that loss of either lp25 or lp28-4 correlated with increased transformation competency. Finally, we demonstrate that linear plasmids lp25 and lp28-4 each encode functional restriction modification systems with distinct but partially overlapping target modification sequences, which likely accounts for the observed decrease in transformation efficiency when those plasmids are present. Taken together, this study describes a role for endogenous plasmids in mammalian infection and restriction protection in the Lyme disease spirochete Borrelia mayonii.
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Affiliation(s)
- Timothy Casselli
- Department of Biological Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Yvonne Tourand
- Department of Biological Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Kaitlyn Gura
- Department of Biological Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Brian Stevenson
- Department of Microbiology, Immunology, and Molecular Genetics, School of Medicine, University of Kentucky, Lexington, Kentucky, USA
- Department of Entomology, University of Kentucky, Lexington, Kentucky, USA
| | - Wolfram R. Zückert
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Catherine A. Brissette
- Department of Biological Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
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10
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Tan X, Lin YP, Pereira MJ, Castellanos M, Hahn BL, Anderson P, Coburn J, Leong JM, Chaconas G. VlsE, the nexus for antigenic variation of the Lyme disease spirochete, also mediates early bacterial attachment to the host microvasculature under shear force. PLoS Pathog 2022; 18:e1010511. [PMID: 35605029 PMCID: PMC9166660 DOI: 10.1371/journal.ppat.1010511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/03/2022] [Accepted: 04/08/2022] [Indexed: 11/19/2022] Open
Abstract
Hematogenous dissemination is a critical step in the evolution of local infection to systemic disease. The Lyme disease (LD) spirochete, which efficiently disseminates to multiple tissues, has provided a model for this process, in particular for the key early event of pathogen adhesion to the host vasculature. This occurs under shear force mediated by interactions between bacterial adhesins and mammalian cell-surface proteins or extracellular matrix (ECM). Using real-time intravital imaging of the Lyme spirochete in living mice, we previously identified BBK32 as the first LD spirochetal adhesin demonstrated to mediate early vascular adhesion in a living mouse; however, deletion of bbk32 resulted in loss of only about half of the early interactions, suggesting the existence of at least one other adhesin (adhesin-X) that promotes early vascular interactions. VlsE, a surface lipoprotein, was identified long ago by its capacity to undergo rapid antigenic variation, is upregulated in the mammalian host and required for persistent infection in immunocompetent mice. In immunodeficient mice, VlsE shares functional overlap with OspC, a multi-functional protein that displays dermatan sulfate-binding activity and is required for joint invasion and colonization. In this research, using biochemical and genetic approaches as well as intravital imaging, we have identified VlsE as adhesin-X; it is a dermatan sulfate (DS) adhesin that efficiently promotes transient adhesion to the microvasculature under shear force via its DS binding pocket. Intravenous inoculation of mice with a low-passage infectious B. burgdorferi strain lacking both bbk32 and vlsE almost completely eliminated transient microvascular interactions. Comparative analysis of binding parameters of VlsE, BBK32 and OspC provides a possible explanation why these three DS adhesins display different functionality in terms of their ability to promote early microvascular interactions.
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Affiliation(s)
- Xi Tan
- Department of Biochemistry & Molecular Biology, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Yi-Pin Lin
- Division of Infectious Diseases, New York State Department of Health, Wadsworth Center, Albany, New York, United States of America
| | - Michael J. Pereira
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Mildred Castellanos
- Department of Biochemistry & Molecular Biology, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Beth L. Hahn
- Department of Medicine, Division of Infectious Diseases, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Phillip Anderson
- Department of Medicine, Division of Infectious Diseases, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Jenifer Coburn
- Department of Medicine, Division of Infectious Diseases, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - John M. Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - George Chaconas
- Departments of Biochemistry & Molecular Biology and Microbiology, Immunology & Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
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Leimer N, Wu X, Imai Y, Morrissette M, Pitt N, Favre-Godal Q, Iinishi A, Jain S, Caboni M, Leus IV, Bonifay V, Niles S, Bargabos R, Ghiglieri M, Corsetti R, Krumpoch M, Fox G, Son S, Klepacki D, Polikanov YS, Freliech CA, McCarthy JE, Edmondson DG, Norris SJ, D'Onofrio A, Hu LT, Zgurskaya HI, Lewis K. A selective antibiotic for Lyme disease. Cell 2021; 184:5405-5418.e16. [PMID: 34619078 DOI: 10.1016/j.cell.2021.09.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/22/2021] [Accepted: 09/08/2021] [Indexed: 12/11/2022]
Abstract
Lyme disease is on the rise. Caused by a spirochete Borreliella burgdorferi, it affects an estimated 500,000 people in the United States alone. The antibiotics currently used to treat Lyme disease are broad spectrum, damage the microbiome, and select for resistance in non-target bacteria. We therefore sought to identify a compound acting selectively against B. burgdorferi. A screen of soil micro-organisms revealed a compound highly selective against spirochetes, including B. burgdorferi. Unexpectedly, this compound was determined to be hygromycin A, a known antimicrobial produced by Streptomyces hygroscopicus. Hygromycin A targets the ribosomes and is taken up by B. burgdorferi, explaining its selectivity. Hygromycin A cleared the B. burgdorferi infection in mice, including animals that ingested the compound in a bait, and was less disruptive to the fecal microbiome than clinically relevant antibiotics. This selective antibiotic holds the promise of providing a better therapeutic for Lyme disease and eradicating it in the environment.
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Affiliation(s)
- Nadja Leimer
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Xiaoqian Wu
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Yu Imai
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Madeleine Morrissette
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Norman Pitt
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Quentin Favre-Godal
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Akira Iinishi
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Samta Jain
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Mariaelena Caboni
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Inga V Leus
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019, USA
| | - Vincent Bonifay
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019, USA
| | - Samantha Niles
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Rachel Bargabos
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Meghan Ghiglieri
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Rachel Corsetti
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Megan Krumpoch
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Gabriel Fox
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Sangkeun Son
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Dorota Klepacki
- Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yury S Polikanov
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Cecily A Freliech
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, MA 02111, USA
| | - Julie E McCarthy
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, MA 02111, USA
| | - Diane G Edmondson
- Department of Pathology and Laboratory Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77225, USA
| | - Steven J Norris
- Department of Pathology and Laboratory Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77225, USA
| | - Anthony D'Onofrio
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Linden T Hu
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, MA 02111, USA
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019, USA
| | - Kim Lewis
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA.
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12
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Groshong AM, Grassmann AA, Luthra A, McLain MA, Provatas AA, Radolf JD, Caimano MJ. PlzA is a bifunctional c-di-GMP biosensor that promotes tick and mammalian host-adaptation of Borrelia burgdorferi. PLoS Pathog 2021; 17:e1009725. [PMID: 34265024 PMCID: PMC8323883 DOI: 10.1371/journal.ppat.1009725] [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: 05/03/2021] [Revised: 07/30/2021] [Accepted: 06/18/2021] [Indexed: 02/05/2023] Open
Abstract
In this study, we examined the relationship between c-di-GMP and its only known effector protein, PlzA, in Borrelia burgdorferi during the arthropod and mammalian phases of the enzootic cycle. Using a B. burgdorferi strain expressing a plzA point mutant (plzA-R145D) unable to bind c-di-GMP, we confirmed that the protective function of PlzA in ticks is c-di-GMP-dependent. Unlike ΔplzA spirochetes, which are severely attenuated in mice, the plzA-R145D strain was fully infectious, firmly establishing that PlzA serves a c-di-GMP-independent function in mammals. Contrary to prior reports, loss of PlzA did not affect expression of RpoS or RpoS-dependent genes, which are essential for transmission, mammalian host-adaptation and murine infection. To ascertain the nature of PlzA's c-di-GMP-independent function(s), we employed infection models using (i) host-adapted mutant spirochetes for needle inoculation of immunocompetent mice and (ii) infection of scid mice with in vitro-grown organisms. Both approaches substantially restored ΔplzA infectivity, suggesting that PlzA enables B. burgdorferi to overcome an early bottleneck to infection. Furthermore, using a Borrelia strain expressing a heterologous, constitutively active diguanylate cyclase, we demonstrate that 'ectopic' production of c-di-GMP in mammals abrogates spirochete virulence and interferes with RpoS function at the post-translational level in a PlzA-dependent manner. Structural modeling and SAXS analysis of liganded- and unliganded-PlzA revealed marked conformational changes that underlie its biphasic functionality. This structural plasticity likely enables PlzA to serve as a c-di-GMP biosensor that in its respective liganded and unliganded states promote vector- and host-adaptation by the Lyme disease spirochete.
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Affiliation(s)
- Ashley M. Groshong
- Department of Medicine, UConn Health, Farmington, Connecticut, United States of America
- Department of Pediatrics, UConn Health, Farmington, Connecticut, United States of America
| | - André A. Grassmann
- Department of Medicine, UConn Health, Farmington, Connecticut, United States of America
| | - Amit Luthra
- Department of Medicine, UConn Health, Farmington, Connecticut, United States of America
| | - Melissa A. McLain
- Department of Medicine, UConn Health, Farmington, Connecticut, United States of America
| | - Anthony A. Provatas
- Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, Connecticut, United States of America
| | - Justin D. Radolf
- Department of Medicine, UConn Health, Farmington, Connecticut, United States of America
- Department of Pediatrics, UConn Health, Farmington, Connecticut, United States of America
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, United States of America
- Department of Genetics and Genome Science, UConn Health, Farmington, Connecticut, United States of America
- Department of Immunology, UConn Health, Farmington, Connecticut, United States of America
| | - Melissa J. Caimano
- Department of Medicine, UConn Health, Farmington, Connecticut, United States of America
- Department of Pediatrics, UConn Health, Farmington, Connecticut, United States of America
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, United States of America
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13
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Wachter J, Martens C, Barbian K, Rego ROM, Rosa P. Epigenomic Landscape of Lyme Disease Spirochetes Reveals Novel Motifs. mBio 2021; 12:e0128821. [PMID: 34156261 PMCID: PMC8262957 DOI: 10.1128/mbio.01288-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 05/07/2021] [Indexed: 11/20/2022] Open
Abstract
Borrelia burgdorferi, the etiological agent of Lyme disease, persists in nature through an enzootic cycle consisting of a vertebrate host and an Ixodes tick vector. The sequence motifs modified by two well-characterized restriction/modification (R/M) loci of B. burgdorferi type strain B31 were recently described, but the methylation profiles of other Lyme disease Borrelia bacteria have not been characterized. Here, the methylomes of B. burgdorferi type strain B31 and 7 clonal derivatives, along with B. burgdorferi N40, B. burgdorferi 297, B. burgdorferi CA-11, B. afzelii PKo, B. afzelii BO23, and B. garinii PBr, were defined through PacBio single-molecule real-time (SMRT) sequencing. This analysis revealed 9 novel sequence motifs methylated by the plasmid-encoded restriction/modification enzymes of these Borrelia strains. Furthermore, while a previous analysis of B. burgdorferi B31 revealed an epigenetic impact of methylation on the global transcriptome, the current data contradict those findings; our analyses of wild-type B. burgdorferi B31 revealed no consistent differences in gene expression among isogenic derivatives lacking one or more restriction/modification enzymes. IMPORTANCE The principal causative agent of Lyme disease in humans in the United States is Borrelia burgdorferi, while B. burgdorferi, B. afzelii, and B. garinii, collectively members of the Borrelia burgdorferi sensu lato species complex, cause Lyme disease in Europe and Asia. Two plasmid-encoded restriction/modification systems have been shown to limit the genetic transformation of B. burgdorferi type strain B31 with foreign DNA, but little is known about the restriction/modification systems of other Lyme disease Borrelia bacteria. This paper describes the methylation motifs present on genomic DNAs of multiple B. burgdorferi, B. afzelii, and B. garinii strains. Contrary to a previous report, we did not find evidence for an epigenetic impact on gene expression by methylation. Knowledge of the motifs recognized and methylated by the restriction/modification enzymes of Lyme disease Borrelia will facilitate molecular genetic investigations of these important human pathogens. Additionally, the similar motifs methylated by orthologous restriction/modification systems of Lyme disease Borrelia bacteria and the presence of these motifs within recombinogenic loci suggest a biological role for these ubiquitous restriction/modification systems in horizontal gene transfer.
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Affiliation(s)
- Jenny Wachter
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Craig Martens
- Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Kent Barbian
- Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Ryan O. M. Rego
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Patricia Rosa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
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14
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Seshu J, Moy BE, Ingle TM. Transformation of Borrelia burgdorferi. Curr Protoc 2021; 1:e61. [PMID: 33661557 DOI: 10.1002/cpz1.61] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Transformation techniques used to genetically manipulate Borrelia burgdorferi, the agent of Lyme disease, play a critical role in generating mutants that facilitate analyses of the role of genes in the pathophysiology of this bacterium. A number of borrelial mutants have been successfully isolated and characterized since the first electrotransformation procedure was established 25 years ago (Samuels, 1995). This article is directed at additional considerations for transforming infectious B. burgdorferi to generate strains retaining the plasmid profile of the parental strain, enabling analysis of transformants for in vitro and in vivo phenotypes. These methods are built on previously published protocols and are intended to add steps and tips to enhance transformation efficiency and recovery of strains amenable for studies involving colonization, survival, and transmission of B. burgdorferi during the vector and vertebrate phases of infection. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Preparation of stock cultures, propagation of spirochetes, and analysis of plasmid profiles Basic Protocol 2: Preparation of plasmid and linear DNA templates for transformation Basic Protocol 3: Transformation of B. burgdorferi Basic Protocol 4: Antibiotic selection of borrelial transformants Basic Protocol 5: Isolation of borrelial transformants in agar overlays Basic Protocol 6: Complementation of mutant borrelial strains in cis or in trans.
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Affiliation(s)
- J Seshu
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, Texas
| | - Brian E Moy
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, Texas
| | - Taylor MacMackin Ingle
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, Texas
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15
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Ante VM, Farris LC, Saputra EP, Hall AJ, O'Bier NS, Oliva Chávez AS, Marconi RT, Lybecker MC, Hyde JA. The Borrelia burgdorferi Adenylate Cyclase, CyaB, Is Important for Virulence Factor Production and Mammalian Infection. Front Microbiol 2021; 12:676192. [PMID: 34113333 PMCID: PMC8186283 DOI: 10.3389/fmicb.2021.676192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 04/16/2021] [Indexed: 12/21/2022] Open
Abstract
Borrelia burgdorferi, the causative agent of Lyme disease, traverses through vastly distinct environments between the tick vector and the multiple phases of the mammalian infection that requires genetic adaptation for the progression of pathogenesis. Borrelial gene expression is highly responsive to changes in specific environmental signals that initiate the RpoS regulon for mammalian adaptation, but the mechanism(s) for direct detection of environmental cues has yet to be identified. Secondary messenger cyclic adenosine monophosphate (cAMP) produced by adenylate cyclase is responsive to environmental signals, such as carbon source and pH, in many bacterial pathogens to promote virulence by altering gene regulation. B. burgdorferi encodes a single non-toxin class IV adenylate cyclase (bb0723, cyaB). This study investigates cyaB expression along with its influence on borrelial virulence regulation and mammalian infectivity. Expression of cyaB was specifically induced with co-incubation of mammalian host cells that was not observed with cultivated tick cells suggesting that cyaB expression is influenced by cellular factor(s) unique to mammalian cell lines. The 3′ end of cyaB also encodes a small RNA, SR0623, in the same orientation that overlaps with bb0722. The differential processing of cyaB and SR0623 transcripts may alter the ability to influence function in the form of virulence determinant regulation and infectivity. Two independent cyaB deletion B31 strains were generated in 5A4-NP1 and ML23 backgrounds and complemented with the cyaB ORF alone that truncates SR0623, cyaB with intact SR0623, or cyaB with a mutagenized full-length SR0623 to evaluate the influence on transcriptional and posttranscriptional regulation of borrelial virulence factors and infectivity. In the absence of cyaB, the expression and production of ospC was significantly reduced, while the protein levels for BosR and DbpA were substantially lower than parental strains. Infectivity studies with both independent cyaB mutants demonstrated an attenuated phenotype with reduced colonization of tissues during early disseminated infection. This work suggests that B. burgdorferi utilizes cyaB and potentially cAMP as a regulatory pathway to modulate borrelial gene expression and protein production to promote borrelial virulence and dissemination in the mammalian host.
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Affiliation(s)
- Vanessa M Ante
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX, United States
| | - Lauren C Farris
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX, United States
| | - Elizabeth P Saputra
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX, United States
| | - Allie J Hall
- Department of Biology, University of Colorado at Colorado Springs, Colorado Springs, CO, United States
| | - Nathaniel S O'Bier
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, VA, United States
| | - Adela S Oliva Chávez
- Department of Entomology, Texas A&M University, College Station, TX, United States
| | - Richard T Marconi
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, VA, United States
| | - Meghan C Lybecker
- Department of Biology, University of Colorado at Colorado Springs, Colorado Springs, CO, United States
| | - Jenny A Hyde
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX, United States
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16
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Sato K, Kumagai Y, Sekizuka T, Kuroda M, Hayashi T, Takano A, Gaowa, Taylor KR, Ohnishi M, Kawabata H. Vitronectin binding protein, BOM1093, confers serum resistance on Borrelia miyamotoi. Sci Rep 2021; 11:5462. [PMID: 33750855 PMCID: PMC7943577 DOI: 10.1038/s41598-021-85069-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 02/23/2021] [Indexed: 11/13/2022] Open
Abstract
Borrelia miyamotoi, a member of the tick-borne relapsing fever spirochetes, shows a serum-resistant phenotype in vitro. This ability of B. miyamotoi may contribute to bacterial evasion of the host innate immune system. To investigate the molecular mechanism of serum-resistance, we constructed a membrane protein-encoding gene library of B. miyamotoi using Borrelia garinii strain HT59G, which shows a transformable and serum-susceptible phenotype. By screening the library, we found that bom1093 and bom1515 of B. miyamotoi provided a serum-resistant phenotype to the recipient B. garinii. These B. miyamotoi genes are predicted to encode P35-like antigen genes and are conserved among relapsing fever borreliae. Functional analysis revealed that BOM1093 bound to serum vitronectin and that the C-terminal region of BOM1093 was involved in the vitronectin-binding property. Importantly, the B. garinii transformant was not serum-resistant when the C terminus-truncated BOM1093 was expressed. We also observed that the depletion of vitronectin from human serum enhances the bactericidal activity of BOM1093 expressing B. garinii, and the survival rate of BOM1093 expressing B. garinii in vitronectin-depleted serum is enhanced by the addition of purified vitronectin. Our data suggests that B. miyamotoi utilize BOM1093-mediated binding to vitronectin as a mechanism of serum resistance.
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Affiliation(s)
- Kozue Sato
- Department of Bacteriology-I, National Institute of Infectious Disease, Toyama 1-23-1, Shinjuku, Tokyo, 162-8640, Japan
| | - Yumi Kumagai
- Department of Bacteriology-I, National Institute of Infectious Disease, Toyama 1-23-1, Shinjuku, Tokyo, 162-8640, Japan
- Department of Host Defense and Biochemical Research, School of Medicine, Juntendo University, Tokyo, 113-8421, Japan
| | - Tsuyoshi Sekizuka
- Pathogen Genomics Center, National Institute of Infectious Disease, Tokyo, 162-8640, Japan
| | - Makoto Kuroda
- Pathogen Genomics Center, National Institute of Infectious Disease, Tokyo, 162-8640, Japan
| | - Tetsuya Hayashi
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu University, Fukuoka, 819-0395, Japan
| | - Ai Takano
- Laboratory of Veterinary Epidemiology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, 753-8511, Japan
| | - Gaowa
- Inner Mongolia Key Laboratory of Tick-Borne Zoonotic Infectious Disease, Department of Medicine, College of Hetao, Bayannur, China
| | - Kyle R Taylor
- College of Veterinary Medicine, Washington State University, Pullman, USA
| | - Makoto Ohnishi
- Department of Bacteriology-I, National Institute of Infectious Disease, Toyama 1-23-1, Shinjuku, Tokyo, 162-8640, Japan
| | - Hiroki Kawabata
- Department of Bacteriology-I, National Institute of Infectious Disease, Toyama 1-23-1, Shinjuku, Tokyo, 162-8640, Japan.
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17
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Groshong AM, McLain MA, Radolf JD. Host-specific functional compartmentalization within the oligopeptide transporter during the Borrelia burgdorferi enzootic cycle. PLoS Pathog 2021; 17:e1009180. [PMID: 33428666 PMCID: PMC7822543 DOI: 10.1371/journal.ppat.1009180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 01/22/2021] [Accepted: 11/23/2020] [Indexed: 12/27/2022] Open
Abstract
Borrelia burgdorferi must acquire all of its amino acids (AAs) from its arthropod vector and vertebrate host. Previously, we determined that peptide uptake via the oligopeptide (Opp) ABC transporter is essential for spirochete viability in vitro and during infection. Our prior study also suggested that B. burgdorferi employs temporal regulation in concert with structural variation of oligopeptide-binding proteins (OppAs) to meet its AA requirements in each biological niche. Herein, we evaluated the contributions to the B. burgdorferi enzootic cycle of three of the spirochete's five OppAs (OppA1, OppA2, and OppA5). An oppA1 transposon (tn) mutant lysed in the hyperosmolar environment of the feeding tick, suggesting that OppA1 imports amino acids required for osmoprotection. The oppA2tn mutant displayed a profound defect in hematogenous dissemination in mice, yet persisted within skin while inducing only a minimal antibody response. These results, along with slightly decreased growth of the oppA2tn mutant within DMCs, suggest that OppA2 serves a minor nutritive role, while its dissemination defect points to an as yet uncharacterized signaling function. Previously, we identified a role for OppA5 in spirochete persistence within the mammalian host. We now show that the oppA5tn mutant displayed no defect during the tick phase of the cycle and could be tick-transmitted to naïve mice. Instead of working in tandem, however, OppA2 and OppA5 appear to function in a hierarchical manner; the ability of OppA5 to promote persistence relies upon the ability of OppA2 to facilitate dissemination. Structural homology models demonstrated variations within the binding pockets of OppA1, 2, and 5 indicative of different peptide repertoires. Rather than being redundant, B. burgdorferi's multiplicity of Opp binding proteins enables host-specific functional compartmentalization during the spirochete lifecycle.
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Affiliation(s)
- Ashley M. Groshong
- Department of Medicine, UConn Health, Farmington, Connecticut, United States of America
- Department of Pediatrics, UConn Health, Farmington, Connecticut, United States of America
- * E-mail:
| | - Melissa A. McLain
- Department of Medicine, UConn Health, Farmington, Connecticut, United States of America
| | - Justin D. Radolf
- Department of Medicine, UConn Health, Farmington, Connecticut, United States of America
- Department of Pediatrics, UConn Health, Farmington, Connecticut, United States of America
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, United States of America
- Department of Genetics and Genome Science, UConn Health, Farmington, Connecticut, United States of America
- Department of Immunology, UConn Health, Farmington, Connecticut, United States of America
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18
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DeHart TG, Kushelman MR, Hildreth SB, Helm RF, Jutras BL. The unusual cell wall of the Lyme disease spirochaete Borrelia burgdorferi is shaped by a tick sugar. Nat Microbiol 2021; 6:1583-1592. [PMID: 34819646 PMCID: PMC8612929 DOI: 10.1038/s41564-021-01003-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 10/20/2021] [Indexed: 01/10/2023]
Abstract
Peptidoglycan-a mesh sac of glycans that are linked by peptides-is the main component of bacterial cell walls. Peptidoglycan provides structural strength, protects cells from osmotic pressure and contributes to shape. All bacterial glycans are repeating disaccharides of N-acetylglucosamine (GlcNAc) β-(1-4)-linked to N-acetylmuramic acid (MurNAc). Borrelia burgdorferi, the tick-borne Lyme disease pathogen, produces glycan chains in which MurNAc is occasionally replaced with an unknown sugar. Nuclear magnetic resonance, liquid chromatography-mass spectroscopy and genetic analyses show that B. burgdorferi produces glycans that contain GlcNAc-GlcNAc. This unusual disaccharide is chitobiose, a component of its chitinous tick vector. Mutant bacteria that are auxotrophic for chitobiose have altered morphology, reduced motility and cell envelope defects that probably result from producing peptidoglycan that is stiffer than that in wild-type bacteria. We propose that the peptidoglycan of B. burgdorferi probably evolved by adaptation to obligate parasitization of a tick vector, resulting in a biophysical cell-wall alteration to withstand the atypical torque associated with twisting motility.
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Affiliation(s)
- Tanner G. DeHart
- grid.438526.e0000 0001 0694 4940Department of Biochemistry, Virginia Tech, Blacksburg, VA USA ,grid.438526.e0000 0001 0694 4940Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA USA
| | - Mara R. Kushelman
- grid.438526.e0000 0001 0694 4940Department of Biochemistry, Virginia Tech, Blacksburg, VA USA ,grid.438526.e0000 0001 0694 4940Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA USA
| | - Sherry B. Hildreth
- grid.438526.e0000 0001 0694 4940Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA USA
| | - Richard F. Helm
- grid.438526.e0000 0001 0694 4940Department of Biochemistry, Virginia Tech, Blacksburg, VA USA ,grid.438526.e0000 0001 0694 4940Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA USA
| | - Brandon L. Jutras
- grid.438526.e0000 0001 0694 4940Department of Biochemistry, Virginia Tech, Blacksburg, VA USA ,grid.438526.e0000 0001 0694 4940Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA USA ,grid.438526.e0000 0001 0694 4940Molecular and Cellular Biology, Virginia Tech, Blacksburg, VA USA ,grid.438526.e0000 0001 0694 4940Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA USA ,grid.438526.e0000 0001 0694 4940Center for Emerging, Zoonotic and Arthropod-borne Pathogens, Virginia Tech, Blacksburg, VA USA
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19
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Coburn J, Garcia B, Hu LT, Jewett MW, Kraiczy P, Norris SJ, Skare J. Lyme Disease Pathogenesis. Curr Issues Mol Biol 2020; 42:473-518. [PMID: 33353871 DOI: 10.21775/cimb.042.473] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Lyme disease Borrelia are obligately parasitic, tick- transmitted, invasive, persistent bacterial pathogens that cause disease in humans and non-reservoir vertebrates primarily through the induction of inflammation. During transmission from the infected tick, the bacteria undergo significant changes in gene expression, resulting in adaptation to the mammalian environment. The organisms multiply and spread locally and induce inflammatory responses that, in humans, result in clinical signs and symptoms. Borrelia virulence involves a multiplicity of mechanisms for dissemination and colonization of multiple tissues and evasion of host immune responses. Most of the tissue damage, which is seen in non-reservoir hosts, appears to result from host inflammatory reactions, despite the low numbers of bacteria in affected sites. This host response to the Lyme disease Borrelia can cause neurologic, cardiovascular, arthritic, and dermatologic manifestations during the disseminated and persistent stages of infection. The mechanisms by which a paucity of organisms (in comparison to many other infectious diseases) can cause varied and in some cases profound inflammation and symptoms remains mysterious but are the subjects of diverse ongoing investigations. In this review, we provide an overview of virulence mechanisms and determinants for which roles have been demonstrated in vivo, primarily in mouse models of infection.
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Affiliation(s)
- Jenifer Coburn
- Center For Infectious Disease Research, Medical College of Wisconsin, 8701 Watertown Plank Rd., TBRC C3980, Milwaukee, WI 53226, USA
| | - Brandon Garcia
- Department of Microbiology and Immunology, East Carolina University, Brody School of Medicine, Greenville, NC 27858, USA
| | - Linden T Hu
- Department of Molecular Biology and Microbiology, Vice Dean of Research, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111, USA
| | - Mollie W Jewett
- Immunity and Pathogenesis Division Head, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, 6900 Lake Nona Blvd. Orlando, FL 32827, USA
| | - Peter Kraiczy
- Institute of Medical Microbiology and Infection Control, University Hospital Frankfurt, Goethe University Frankfurt, Paul-Ehrlich-Str. 40, 60596 Frankfurt, Germany
| | - Steven J Norris
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, P.O. Box 20708, Houston, TX 77225, USA
| | - Jon Skare
- Professor and Associate Head, Texas A and M University, 8447 Riverside Pkwy, Bryan, TX 77807, USA
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20
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Abstract
Genetic studies in Borrelia require special consideration of the highly segmented genome, complex growth requirements and evolutionary distance of spirochetes from other genetically tractable bacteria. Despite these challenges, a robust molecular genetic toolbox has been constructed to investigate the biology and pathogenic potential of these important human pathogens. In this review we summarize the tools and techniques that are currently available for the genetic manipulation of Borrelia, including the relapsing fever spirochetes, viewing them in the context of their utility and shortcomings. Our primary objective is to help researchers discern what is feasible and what is not practical when thinking about potential genetic experiments in Borrelia. We have summarized published methods and highlighted their critical elements, but we are not providing detailed protocols. Although many advances have been made since B. burgdorferi was first transformed over 25 years ago, some standard genetic tools remain elusive for Borrelia. We mention these limitations and why they persist, if known. We hope to encourage investigators to explore what might be possible, in addition to optimizing what currently can be achieved, through genetic manipulation of Borrelia.
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Affiliation(s)
- Patricia A. Rosa
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St. Hamilton, MT 59840 USA
| | - Mollie W. Jewett
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, 6900 Lake Nona Blvd, Orlando, FL 32827 USA
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21
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Zhang Y, Chen T, Raghunandanan S, Xiang X, Yang J, Liu Q, Edmondson DG, Norris SJ, Yang XF, Lou Y. YebC regulates variable surface antigen VlsE expression and is required for host immune evasion in Borrelia burgdorferi. PLoS Pathog 2020; 16:e1008953. [PMID: 33048986 PMCID: PMC7584230 DOI: 10.1371/journal.ppat.1008953] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 10/23/2020] [Accepted: 09/02/2020] [Indexed: 02/08/2023] Open
Abstract
Borrelia burgdorferi, the Lyme disease pathogen causes persistent infection by evading the host immune response. Differential expression of the surface-exposed lipoprotein VlsE that undergoes antigenic variation is a key immune evasion strategy employed by B. burgdorferi. Most studies focused on the mechanism of VlsE antigen variation, but little is known about VlsE regulation and factor(s) that regulates differential vlsE expression. In this study, we investigated BB0025, a putative YebC family transcriptional regulator (and hence designated BB0025 as YebC of B. burgdorferi herein). We constructed yebC mutant and complemented strain in an infectious strain of B. burgdorferi. The yebC mutant could infect immunocompromised SCID mice but not immunocompetent mice, suggesting that YebC plays an important role in evading host adaptive immunity. RNA-seq analyses identified vlsE as one of the genes whose expression was most affected by YebC. Quantitative RT-PCR and Western blot analyses confirmed that vlsE expression was dependent on YebC. In vitro, YebC and VlsE were co-regulated in response to growth temperature. In mice, both yebC and vlsE were inversely expressed with ospC in response to the host adaptive immune response. Furthermore, EMSA proved that YebC directly binds to the vlsE promoter, suggesting a direct transcriptional control. These data demonstrate that YebC is a new regulator that modulates expression of vlsE and other genes important for spirochetal infection and immune evasion in the mammalian host.
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Affiliation(s)
- Yan Zhang
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- Optometry and Eye Hospital and School of Ophthalmology, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, China
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Tong Chen
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- Department of Pediatrics, Division of Medical Genetics, Duke University, Durham, North Carolina, United States of America
| | - Sajith Raghunandanan
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Xuwu Xiang
- Department of Anesthesiology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Jing Yang
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Qiang Liu
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Diane G. Edmondson
- Department of Pathology and Laboratory Medicine, UTHealth Medical School, Houston, Texas, United States of America
| | - Steven J. Norris
- Department of Pathology and Laboratory Medicine, UTHealth Medical School, Houston, Texas, United States of America
| | - X. Frank Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Yongliang Lou
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
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22
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Medina-Pérez DN, Wager B, Troy E, Gao L, Norris SJ, Lin T, Hu L, Hyde JA, Lybecker M, Skare JT. The intergenic small non-coding RNA ittA is required for optimal infectivity and tissue tropism in Borrelia burgdorferi. PLoS Pathog 2020; 16:e1008423. [PMID: 32365143 PMCID: PMC7224557 DOI: 10.1371/journal.ppat.1008423] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/14/2020] [Accepted: 04/01/2020] [Indexed: 12/15/2022] Open
Abstract
Post-transcriptional regulation via small regulatory RNAs (sRNAs) has been implicated in diverse regulatory processes in bacteria, including virulence. One class of sRNAs, termed trans-acting sRNAs, can affect the stability and/or the translational efficiency of regulated transcripts. In this study, we utilized a collaborative approach that employed data from infection with the Borrelia burgdorferi Tn library, coupled with Tn-seq, together with borrelial sRNA and total RNA transcriptomes, to identify an intergenic trans-acting sRNA, which we designate here as ittA for infectivity-associated and tissue-tropic sRNA locus A. The genetic inactivation of ittA resulted in a significant attenuation in infectivity, with decreased spirochetal load in ear, heart, skin and joint tissues. In addition, the ittA mutant did not disseminate to peripheral skin sites or heart tissue, suggesting a role for ittA in regulating a tissue-tropic response. RNA-Seq analysis determined that 19 transcripts were differentially expressed in the ittA mutant relative to its genetic parent, including vraA, bba66, ospD and oms28 (bba74). Subsequent proteomic analyses also showed a significant decrease of OspD and Oms28 (BBA74) proteins. To our knowledge this is the first documented intergenic sRNA that alters the infectivity potential of B. burgdorferi.
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Affiliation(s)
- Diana N. Medina-Pérez
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, Texas, United States of America
| | - Beau Wager
- Department of Molecular Biology and Microbiology, Tufts University, School of Medicine, Boston, Massachusetts, United States of America
| | - Erin Troy
- Department of Molecular Biology and Microbiology, Tufts University, School of Medicine, Boston, Massachusetts, United States of America
| | - Lihui Gao
- Department of Pathology and Laboratory Medicine, McGovern Medical School, University of Texas Health Science Center, Houston, Houston, Texas, United States of America
| | - Steven J. Norris
- Department of Pathology and Laboratory Medicine, McGovern Medical School, University of Texas Health Science Center, Houston, Houston, Texas, United States of America
| | - Tao Lin
- Department of Pathology and Laboratory Medicine, McGovern Medical School, University of Texas Health Science Center, Houston, Houston, Texas, United States of America
| | - Linden Hu
- Department of Molecular Biology and Microbiology, Tufts University, School of Medicine, Boston, Massachusetts, United States of America
| | - Jenny A. Hyde
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, Texas, United States of America
| | - Meghan Lybecker
- Department of Biology, University of Colorado at Colorado Springs, Colorado Springs, Colorado, United States of America
| | - Jon T. Skare
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, Texas, United States of America
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23
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Caimano MJ, Groshong AM, Belperron A, Mao J, Hawley KL, Luthra A, Graham DE, Earnhart CG, Marconi RT, Bockenstedt LK, Blevins JS, Radolf JD. The RpoS Gatekeeper in Borrelia burgdorferi: An Invariant Regulatory Scheme That Promotes Spirochete Persistence in Reservoir Hosts and Niche Diversity. Front Microbiol 2019; 10:1923. [PMID: 31507550 PMCID: PMC6719511 DOI: 10.3389/fmicb.2019.01923] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/05/2019] [Indexed: 11/28/2022] Open
Abstract
Maintenance of Borrelia burgdorferi within its enzootic cycle requires a complex regulatory pathway involving the alternative σ factors RpoN and RpoS and two ancillary trans-acting factors, BosR and Rrp2. Activation of this pathway occurs within ticks during the nymphal blood meal when RpoS, the effector σ factor, transcribes genes required for tick transmission and mammalian infection. RpoS also exerts a 'gatekeeper' function by repressing σ70-dependent tick phase genes (e.g., ospA, lp6.6). Herein, we undertook a broad examination of RpoS functionality throughout the enzootic cycle, beginning with modeling to confirm that this alternative σ factor is a 'genuine' RpoS homolog. Using a novel dual color reporter system, we established at the single spirochete level that ospA is expressed in nymphal midguts throughout transmission and is not downregulated until spirochetes have been transmitted to a naïve host. Although it is well established that rpoS/RpoS is expressed throughout infection, its requirement for persistent infection has not been demonstrated. Plasmid retention studies using a trans-complemented ΔrpoS mutant demonstrated that (i) RpoS is required for maximal fitness throughout the mammalian phase and (ii) RpoS represses tick phase genes until spirochetes are acquired by a naïve vector. By transposon mutant screening, we established that bba34/oppA5, the only OppA oligopeptide-binding protein controlled by RpoS, is a bona fide persistence gene. Lastly, comparison of the strain 297 and B31 RpoS DMC regulons identified two cohorts of RpoS-regulated genes. The first consists of highly conserved syntenic genes that are similarly regulated by RpoS in both strains and likely required for maintenance of B. burgdorferi sensu stricto strains in the wild. The second includes RpoS-regulated plasmid-encoded variable surface lipoproteins ospC, dbpA and members of the ospE/ospF/elp, mlp, revA, and Pfam54 paralogous gene families, all of which have evolved via inter- and intra-strain recombination. Thus, while the RpoN/RpoS pathway regulates a 'core' group of orthologous genes, diversity within RpoS regulons of different strains could be an important determinant of reservoir host range as well as spirochete virulence.
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Affiliation(s)
- Melissa J. Caimano
- Department of Medicine, UConn Health, Farmington, CT, United States,Department of Pediatrics, UConn Health, Farmington, CT, United States,Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, United States,*Correspondence: Melissa J. Caimano,
| | | | - Alexia Belperron
- Department of Internal Medicine, Section of Rheumatology, Allergy and Immunology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Jialing Mao
- Department of Internal Medicine, Section of Rheumatology, Allergy and Immunology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Kelly L. Hawley
- Department of Pediatrics, UConn Health, Farmington, CT, United States,Division of Infectious Diseases and Immunology, Connecticut Children’s Medical Center, Hartford, CT, United States
| | - Amit Luthra
- Department of Medicine, UConn Health, Farmington, CT, United States
| | - Danielle E. Graham
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Christopher G. Earnhart
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, VA, United States
| | - Richard T. Marconi
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, VA, United States
| | - Linda K. Bockenstedt
- Department of Internal Medicine, Section of Rheumatology, Allergy and Immunology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Jon S. Blevins
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Justin D. Radolf
- Department of Medicine, UConn Health, Farmington, CT, United States,Department of Pediatrics, UConn Health, Farmington, CT, United States,Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, United States,Department of Genetics and Genome Science, UConn Health, Farmington, CT, United States,Department of Immunology, UConn Health, Farmington, CT, United States
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24
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Jutras BL, Savage CR, Arnold WK, Lethbridge KG, Carroll DW, Tilly K, Bestor A, Zhu H, Seshu J, Zückert WR, Stewart PE, Rosa PA, Brissette CA, Stevenson B. The Lyme disease spirochete's BpuR DNA/RNA-binding protein is differentially expressed during the mammal-tick infectious cycle, which affects translation of the SodA superoxide dismutase. Mol Microbiol 2019; 112:973-991. [PMID: 31240776 PMCID: PMC6736767 DOI: 10.1111/mmi.14336] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2019] [Indexed: 12/24/2022]
Abstract
When the Lyme disease spirochete, Borrelia burgdorferi, transfers from a feeding tick into a human or other vertebrate host, the bacterium produces vertebrate‐specific proteins and represses factors needed for arthropod colonization. Previous studies determined that the B. burgdorferi BpuR protein binds to its own mRNA and autoregulates its translation, and also serves as co‐repressor of erp transcription. Here, we demonstrate that B. burgdorferi controls transcription of bpuR, expressing high levels of bpuR during tick colonization but significantly less during mammalian infection. The master regulator of chromosomal replication, DnaA, was found to bind specifically to a DNA sequence that overlaps the bpuR promoter. Cultured B. burgdorferi that were genetically manipulated to produce elevated levels of BpuR exhibited altered levels of several proteins, although BpuR did not impact mRNA levels. Among these was the SodA superoxide dismutase, which is essential for mammalian infection. BpuR bound to sodA mRNA in live B. burgdorferi, and a specific BpuR‐binding site was mapped 5′ of the sodA open reading frame. Recognition of posttranscriptional regulation of protein levels by BpuR adds another layer to our understanding of the B. burgdorferi regulome, and provides further evidence that bacterial protein levels do not always correlate directly with mRNA levels.
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Affiliation(s)
- Brandon L Jutras
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Christina R Savage
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, USA
| | - William K Arnold
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Kathryn G Lethbridge
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Dustin W Carroll
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Kit Tilly
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Aaron Bestor
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Haining Zhu
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Janakiram Seshu
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, USA
| | - Wolfram R Zückert
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Philip E Stewart
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Patricia A Rosa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Catherine A Brissette
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Brian Stevenson
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, USA.,Department of Entomology, University of Kentucky, Lexington, KY, USA
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25
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Abstract
The spirochetes Borrelia (Borreliella) burgdorferi and Borrelia hermsii, the etiologic agents of Lyme disease and relapsing fever, respectively, cycle in nature between an arthropod vector and a vertebrate host. They have extraordinarily unusual genomes that are highly segmented and predominantly linear. The genetic analyses of Lyme disease spirochetes have become increasingly more sophisticated, while the age of genetic investigation in the relapsing fever spirochetes is just dawning. Molecular tools available for B. burgdorferi and related species range from simple selectable markers and gene reporters to state-of-the-art inducible gene expression systems that function in the animal model and high-throughput mutagenesis methodologies, despite nearly overwhelming experimental obstacles. This armamentarium has empowered borreliologists to build a formidable genetic understanding of the cellular physiology of the spirochete and the molecular pathogenesis of Lyme disease.
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Affiliation(s)
- Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA.
| | - D Scott Samuels
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA.
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26
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Abstract
This chapter covers the progress made in the Leptospira field since the application of mutagenesis techniques and how they have allowed the study of virulence factors and, more generally, the biology of Leptospira. The last decade has seen advances in our ability to perform molecular genetic analysis of Leptospira. Major achievements include the generation of large collections of mutant strains and the construction of replicative plasmids, enabling complementation of mutations. However, there are still no practical tools for routine genetic manipulation of pathogenic Leptospira strains, slowing down advances in pathogenesis research. This review summarizes the status of the molecular genetic toolbox for Leptospira species and highlights new challenges in the nascent field of Leptospira genetics.
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Affiliation(s)
- Mathieu Picardeau
- Biology of Spirochetes Unit, Institut Pasteur, 28 Rue Du Docteur Roux, 75724, Paris Cedex 15, France.
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27
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Phelan JP, Kern A, Ramsey ME, Lundt ME, Sharma B, Lin T, Gao L, Norris SJ, Hyde JA, Skare JT, Hu LT. Genome-wide screen identifies novel genes required for Borrelia burgdorferi survival in its Ixodes tick vector. PLoS Pathog 2019; 15:e1007644. [PMID: 31086414 PMCID: PMC6516651 DOI: 10.1371/journal.ppat.1007644] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 02/15/2019] [Indexed: 12/25/2022] Open
Abstract
Borrelia burgdorferi, the causative agent of Lyme disease in humans, is maintained in a complex biphasic life cycle, which alternates between tick and vertebrate hosts. To successfully survive and complete its enzootic cycle, B. burgdorferi adapts to diverse hosts by regulating genes required for survival in specific environments. Here we describe the first ever use of transposon insertion sequencing (Tn-seq) to identify genes required for B. burgdorferi survival in its tick host. We found that insertions into 46 genes resulted in a complete loss of recovery of mutants from larval Ixodes ticks. Insertions in an additional 56 genes resulted in a >90% decrease in fitness. The screen identified both previously known and new genes important for larval tick survival. Almost half of the genes required for survival in the tick encode proteins of unknown function, while a significant portion (over 20%) encode membrane-associated proteins or lipoproteins. We validated the results of the screen for five Tn mutants by performing individual competition assays using mutant and complemented strains. To better understand the role of one of these genes in tick survival, we conducted mechanistic studies of bb0017, a gene previously shown to be required for resistance against oxidative stress. In this study we show that BB0017 affects the regulation of key borrelial virulence determinants. The application of Tn-seq to in vivo screening of B. burgdorferi in its natural vector is a powerful tool that can be used to address many different aspects of the host pathogen interaction. Borrelia burgdorferi, the causative agent of Lyme disease, must adjust to environmental changes as it moves between its tick and vertebrate hosts. We performed a screen of a B. burgdorferi transposon library using massively parallel sequencing (Tn-seq) to identify fitness defects involved in survival in its tick host. This screen accurately identified genes known to cause decreased fitness for tick survival and identified new genes involved in B. burgdorferi survival in ticks. All of the genes tested individually confirmed the Tn-seq results. One of the genes identified encodes a protein whose function was previously unknown that appears to be involved in regulating expression of proteins known to be involved in environmental adaptation. Tn-seq is a powerful tool for understanding vector-pathogen interactions and may reveal new opportunities for interrupting the infectious cycle of vector-borne diseases.
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Affiliation(s)
- James P. Phelan
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, United States of America
- * E-mail: (JPP); (STH)
| | - Aurelie Kern
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, United States of America
| | - Meghan E. Ramsey
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, United States of America
| | - Maureen E. Lundt
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, United States of America
| | - Bijaya Sharma
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, United States of America
| | - Tao Lin
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lihui Gao
- MD Anderson Cancer Center Thoracic & Cardiovascular Surgery, Houston, Texas, United States of America
| | - Steven J. Norris
- Department of Pathology and Laboratory Medicine, McGovern Medical School at UT Health, Houston, Texas, United States of America
| | - Jenny A. Hyde
- Department of Microbial Pathogenesis and Immunology, Texas A & M University Health Science Center, Bryan, Texas, United States of America
| | - Jon T. Skare
- Department of Microbial Pathogenesis and Immunology, Texas A & M University Health Science Center, Bryan, Texas, United States of America
| | - Linden T. Hu
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, United States of America
- * E-mail: (JPP); (STH)
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28
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Casselli T, Crowley MA, Highland MA, Tourand Y, Bankhead T. A small intergenic region of lp17 is required for evasion of adaptive immunity and induction of pathology by the Lyme disease spirochete. Cell Microbiol 2019; 21:e13029. [PMID: 30945408 DOI: 10.1111/cmi.13029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 03/07/2019] [Accepted: 03/30/2019] [Indexed: 01/15/2023]
Abstract
The causative agent of Lyme disease, Borrelia burgdorferi, harbours a single linear chromosome and upwards of 23 linear and circular plasmids. Only a minority of these plasmids, including linear plasmid 17, are maintained with near-absolute fidelity during extended in vitro passage, and characterisation of any putative virulence determinants they encode has only recently begun. In this work, a mutant lacking a ~4.7 kb fragment of lp17 was studied. Colonisation of murine tissues by this lp17 mutant was significantly impaired, as was the ability to induce carditis and arthritis. The deficiency in tissue colonisation was alleviated in severe combined immunodeficient (SCID) mice, implicating a role for this plasmid region in adaptive immune evasion. Through genetic complementation, the mutant phenotype could be fully attributed to a 317 bp intergenic region that corresponds to the discontinued bbd07 ORF and upstream sequence. The intergenic region was found to be transcriptionally active, and mutant spirochetes lacking this region exhibited an overall difference in the antigenic profile during infection of an immunocompetent murine host. Overall, this study is the first to provide evidence for the involvement of lp17 in colonisation of joint and heart tissues, along with the associated pathologies caused by the Lyme disease spirochete.
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Affiliation(s)
- Timothy Casselli
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Michael A Crowley
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Margaret A Highland
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA.,Animal Disease Research Unit, USDA Agricultural Research Service, Pullman, Washington, USA
| | - Yvonne Tourand
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Troy Bankhead
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
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29
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Takacs CN, Kloos ZA, Scott M, Rosa PA, Jacobs-Wagner C. Fluorescent Proteins, Promoters, and Selectable Markers for Applications in the Lyme Disease Spirochete Borrelia burgdorferi. Appl Environ Microbiol 2018; 84:e01824-18. [PMID: 30315081 PMCID: PMC6275353 DOI: 10.1128/aem.01824-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/08/2018] [Indexed: 11/30/2022] Open
Abstract
Lyme disease is the most widely reported vector-borne disease in the United States. Its incidence is rapidly increasing, and disease symptoms can be debilitating. The need to understand the biology of the disease agent, the spirochete Borrelia burgdorferi, is thus evermore pressing. Despite important advances in B. burgdorferi genetics, the array of molecular tools available for use in this organism remains limited, especially for cell biological studies. Here, we adapt a palette of bright and mostly monomeric fluorescent proteins for versatile use and multicolor imaging in B. burgdorferi We also characterize two novel antibiotic selection markers and establish the feasibility of their use in conjunction with extant markers. Last, we describe a set of promoters of low and intermediate strengths that allow fine-tuning of gene expression levels. These molecular tools complement and expand current experimental capabilities in B. burgdorferi, which will facilitate future investigation of this important human pathogen. To showcase the usefulness of these reagents, we used them to investigate the subcellular localization of BB0323, a B. burgdorferi lipoprotein essential for survival in the host and vector environments. We show that BB0323 accumulates at the cell poles and future division sites of B. burgdorferi cells, highlighting the complex subcellular organization of this spirochete.IMPORTANCE Genetic manipulation of the Lyme disease spirochete B. burgdorferi remains cumbersome, despite significant progress in the field. The scarcity of molecular reagents available for use in this pathogen has slowed research efforts to study its unusual biology. Of interest, B. burgdorferi displays complex cellular organization features that have yet to be understood. These include an unusual morphology and a highly fragmented genome, both of which are likely to play important roles in the bacterium's transmission, infectivity, and persistence. Here, we complement and expand the array of molecular tools available for use in B. burgdorferi by generating and characterizing multiple fluorescent proteins, antibiotic selection markers, and promoters of varied strengths. These tools will facilitate investigations in this important human pathogen, as exemplified by the polar and midcell localization of the cell envelope regulator BB0323, which we uncovered using these reagents.
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Affiliation(s)
- Constantin N Takacs
- Microbial Sciences Institute, Yale West Campus, West Haven, Connecticut, USA
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale West Campus, West Haven, Connecticut, USA
| | - Zachary A Kloos
- Microbial Sciences Institute, Yale West Campus, West Haven, Connecticut, USA
- Microbiology Program, Yale University, New Haven, Connecticut, USA
| | - Molly Scott
- Microbial Sciences Institute, Yale West Campus, West Haven, Connecticut, USA
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale West Campus, West Haven, Connecticut, USA
| | - Patricia A Rosa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Christine Jacobs-Wagner
- Microbial Sciences Institute, Yale West Campus, West Haven, Connecticut, USA
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale West Campus, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
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DNA Methylation by Restriction Modification Systems Affects the Global Transcriptome Profile in Borrelia burgdorferi. J Bacteriol 2018; 200:JB.00395-18. [PMID: 30249703 DOI: 10.1128/jb.00395-18] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 09/18/2018] [Indexed: 02/08/2023] Open
Abstract
Prokaryote restriction modification (RM) systems serve to protect bacteria from potentially detrimental foreign DNA. Recent evidence suggests that DNA methylation by the methyltransferase (MTase) components of RM systems can also have effects on transcriptome profiles. The type strain of the causative agent of Lyme disease, Borrelia burgdorferi B31, possesses two RM systems with N6-methyladenosine (m6A) MTase activity, which are encoded by the bbe02 gene located on linear plasmid lp25 and bbq67 on lp56. The specific recognition and/or methylation sequences had not been identified for either of these B. burgdorferi MTases, and it was not previously known whether these RM systems influence transcript levels. In the current study, single-molecule real-time sequencing was utilized to map genome-wide m6A sites and to identify consensus modified motifs in wild-type B. burgdorferi as well as MTase mutants lacking either the bbe02 gene alone or both bbe02 and bbq67 genes. Four novel conserved m6A motifs were identified and were fully attributable to the presence of specific MTases. Whole-genome transcriptome changes were observed in conjunction with the loss of MTase enzymes, indicating that DNA methylation by the RM systems has effects on gene expression. Genes with altered transcription in MTase mutants include those involved in vertebrate host colonization (e.g., rpoS regulon) and acquisition by/transmission from the tick vector (e.g., rrp1 and pdeB). The results of this study provide a comprehensive view of the DNA methylation pattern in B. burgdorferi, and the accompanying gene expression profiles add to the emerging body of research on RM systems and gene regulation in bacteria.IMPORTANCE Lyme disease is the most prevalent vector-borne disease in North America and is classified by the Centers for Disease Control and Prevention (CDC) as an emerging infectious disease with an expanding geographical area of occurrence. Previous studies have shown that the causative bacterium, Borrelia burgdorferi, methylates its genome using restriction modification systems that enable the distinction from foreign DNA. Although much research has focused on the regulation of gene expression in B. burgdorferi, the effect of DNA methylation on gene regulation has not been evaluated. The current study characterizes the patterns of DNA methylation by restriction modification systems in B. burgdorferi and evaluates the resulting effects on gene regulation in this important pathogen.
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Zhang JJ, Chen T, Yang Y, Du J, Li H, Troxell B, He M, Carrasco SE, Gomelsky M, Yang XF. Positive and Negative Regulation of Glycerol Utilization by the c-di-GMP Binding Protein PlzA in Borrelia burgdorferi. J Bacteriol 2018; 200:e00243-18. [PMID: 30181123 PMCID: PMC6199477 DOI: 10.1128/jb.00243-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/27/2018] [Indexed: 02/06/2023] Open
Abstract
Borrelia burgdorferi, the causative agent of Lyme disease, encounters two disparate host environments during its enzootic life cycle, Ixodes ticks and mammalian hosts. B. burgdorferi has a small genome that encodes a streamlined cyclic dimeric GMP (c-di-GMP) signaling system comprising a single diguanylate cyclase, Rrp1, and two phosphodiesterases. This system is essential for spirochete survival in ticks, in part because it controls the expression of the glp operon involved in glycerol utilization. In this study, we showed that a B. burgdorferi c-di-GMP receptor, PlzA, functions as both a positive and a negative regulator for glp expression. Deletion of plzA or mutation in plzA that impaired c-di-GMP binding abolished glp expression. On the other hand, overexpression of plzA resulted in glp repression, which could be rescued by simultaneous overexpression of rrp1. plzA overexpression in the rrp1 mutant, which is devoid of c-di-GMP, or overexpression of a plzA mutant incapable of c-di-GMP binding further enhanced glp repression. Combined results suggest that c-di-GMP-bound PlzA functions as a positive regulator, whereas ligand-free PlzA acts as a negative regulator for glp expression. Thus, PlzA of B. burgdorferi with a streamlined c-di-GMP signaling system not only controls multiple targets, as previously envisioned, but has also evolved different modes of action.IMPORTANCE The Lyme disease pathogen, Borrelia burgdorferi, has a simple cyclic dimeric GMP (c-di-GMP) signaling system essential for adaptation of the pathogen to the complicated tick environment. The c-di-GMP effector of B. burgdorferi, PlzA, has been shown to regulate multiple cellular processes, including motility, osmolality sensing, and nutrient utilization. The findings of this study demonstrate that PlzA not only controls multiple targets but also has different functional modalities, allowing it to act as both positive and negative regulator of the glp operon expression. This work highlights how bacteria with a small genome can compensate for the limited regulatory repertoire by increasing the complexity of targets and modes of action in their regulatory proteins.
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Affiliation(s)
- Jun-Jie Zhang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Environmental Microbiology Group, Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Tong Chen
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, School of Laboratory Medicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Youyun Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Jimei Du
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, School of Laboratory Medicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Hongxia Li
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Bryan Troxell
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Ming He
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Sebastian E Carrasco
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Mark Gomelsky
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming, USA
| | - X Frank Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Chen T, Xiang X, Xu H, Zhang X, Zhou B, Yang Y, Lou Y, Yang XF. LtpA, a CdnL-type CarD regulator, is important for the enzootic cycle of the Lyme disease pathogen. Emerg Microbes Infect 2018; 7:126. [PMID: 29985409 PMCID: PMC6037790 DOI: 10.1038/s41426-018-0122-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/31/2018] [Accepted: 06/04/2018] [Indexed: 01/12/2023]
Abstract
Little is known about how Borrelia burgdorferi, the Lyme disease pathogen, adapts and survives in the tick vector. We previously identified a bacterial CarD N-terminal-like (CdnL) protein, LtpA (BB0355), in B. burgdorferi that is preferably expressed at lower temperatures, which is a surrogate condition mimicking the tick portion of the enzootic cycle of B. burgdorferi. CdnL-family proteins, an emerging class of bacterial RNAP-interacting transcription factors, are essential for the viability of Mycobacterium tuberculosis and Myxococcus xanthus. Previous attempts to inactivate ltpA in B. burgdorferi have not been successful. In this study, we report the construction of a ltpA mutant in the infectious strain of B. burgdorferi, strain B31-5A4NP1. Unlike CdnL in M. tuberculosis and M. xanthus, LtpA is dispensable for the viability of B. burgdorferi. However, the ltpA mutant exhibits a reduced growth rate and a cold-sensitive phenotype. We demonstrate that LtpA positively regulates 16S rRNA expression, which contributes to the growth defects in the ltpA mutant. The ltpA mutant remains capable of infecting mice, albeit with delayed infection. Additionally, the ltpA mutant produces markedly reduced spirochetal loads in ticks and was not able to infect mice via tick infection. Overall, LtpA represents a novel regulator in the CdnL family that has an important role in the enzootic cycle of B. burgdorferi.
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Affiliation(s)
- Tong Chen
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, School of Laboratory Medicine, Wenzhou Medical University, 325000, Wenzhou, Zhejiang, China.,Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Xuwu Xiang
- Department of Anesthesiology, The First Affiliated Hospital, College of Medicine, Zhejiang University, 310003, Hangzhou, China
| | - Haijun Xu
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Agricultural Entomology, Institute of Insect Sciences, Zhejiang University, 310058, Hangzhou, China
| | - Xuechao Zhang
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Agricultural Entomology, Institute of Insect Sciences, Zhejiang University, 310058, Hangzhou, China
| | - Bibi Zhou
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, School of Laboratory Medicine, Wenzhou Medical University, 325000, Wenzhou, Zhejiang, China.,Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Youyun Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Yongliang Lou
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, School of Laboratory Medicine, Wenzhou Medical University, 325000, Wenzhou, Zhejiang, China.
| | - X Frank Yang
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, School of Laboratory Medicine, Wenzhou Medical University, 325000, Wenzhou, Zhejiang, China. .,Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
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Zhou B, Yang Y, Chen T, Lou Y, Yang XF. The oligopeptide ABC transporter OppA4 negatively regulates the virulence factor OspC production of the Lyme disease pathogen. Ticks Tick Borne Dis 2018; 9:1343-1349. [PMID: 29921537 DOI: 10.1016/j.ttbdis.2018.06.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 06/06/2018] [Accepted: 06/13/2018] [Indexed: 12/18/2022]
Abstract
Borrelia burgdorferi sensu lato, the agent of Lyme disease, exists in nature through a complex enzootic life cycle that involves both ticks and mammals. The B. burgdorferi genome encodes five Oligopeptide ABC transporters (Opp) that are predicted to be involve in transport of various nutrients. Previously, it was reported that OppA5 is important for the optimal production of OspC, a major virulence factor of B. burgdorferi. In this study, possible role of another Oligopeptide ABC transporter, OppA4 in ospC expression was investigated by construction of an oppA4 deletion mutant and the complemented strain. Inactivation of oppA4 resulted an increased production of OspC, suggesting that OppA4 has a negative impact on ospC expression. Expression of ospC is controlled by Rrp2-RpoN-RpoS, the central pathway essential for mammal infection. We showed that increased ospC expression in the oppA4 mutant was due to an increased rpoS expression. We then further investigated how OppA4 negatively regulates this pathway. Two regulators, BosR and BadR, are known to positively and negatively, respectively, regulate the Rrp2-RpoN-RpoS pathway. We found that deletion of oppA4 resulted in an increased level of BosR. Previous reports showed that bosR is mainly regulated at the post-transcriptional level by other factors. However, OppA4 appears to negatively regulate bosR expression at the transcriptional level. The finding of OppA4 involved in regulation of the Rrp2-RpoN-RpoS pathway further reinforces the importance of nutritional virulence to the enzootic cycle of B. burgdorferi.
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Affiliation(s)
- Bibi Zhou
- Zhejiang Provincial Key Laboratory of Medical Genetics, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China; Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Youyun Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Tong Chen
- Zhejiang Provincial Key Laboratory of Medical Genetics, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yongliang Lou
- Zhejiang Provincial Key Laboratory of Medical Genetics, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China.
| | - X Frank Yang
- Zhejiang Provincial Key Laboratory of Medical Genetics, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China; Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States.
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Abstract
Signature-tagged mutagenesis (STM) is a functional genomics approach to identify bacterial virulence determinants and virulence factors by simultaneously screening multiple mutants in a single host animal, and has been utilized extensively for the study of bacterial pathogenesis, host-pathogen interactions, and spirochete and tick biology. The signature-tagged transposon mutagenesis has been developed to investigate virulence determinants and pathogenesis of Borrelia burgdorferi. Mutants in genes important in virulence are identified by negative selection in which the mutants fail to colonize or disseminate in the animal host and tick vector. STM procedure combined with Luminex Flex®Map™ technology and next-generation sequencing (e.g., Tn-seq) are the powerful high-throughput tools for the determination of Borrelia burgdorferi virulence determinants. The assessment of multiple tissue sites and two DNA resources at two different time points using Luminex Flex®Map™ technology provides a robust data set. B. burgdorferi transposon mutant screening indicates that a high proportion of genes are the novel virulence determinants that are required for mouse and tick infection. In this protocol, an effective signature-tagged Himar1-based transposon suicide vector was developed and used to generate a sequence-defined library of nearly 4800 mutants in the infectious B. burgdorferi B31 clone. In STM, signature-tagged suicide vectors are constructed by inserting unique DNA sequences (tags) into the transposable elements. The signature-tagged transposon mutants are generated when transposon suicide vectors are transformed into an infectious B. burgdorferi clone, and the transposable element is transposed into the 5'-TA-3' sequence in the B. burgdorferi genome with the signature tag. The transposon library is created and consists of many sub-libraries, each sub-library has several hundreds of mutants with same tags. A group of mice or ticks are infected with a mixed population of mutants with different tags, after recovered from different tissues of infected mice and ticks, mutants from output pool and input pool are detected using high-throughput, semi-quantitative Luminex® FLEXMAP™ or next-generation sequencing (Tn-seq) technologies. Thus far, we have created a high-density, sequence-defined transposon library of over 6600 STM mutants for the efficient genome-wide investigation of genes and gene products required for wild-type pathogenesis, host-pathogen interactions, in vitro growth, in vivo survival, physiology, morphology, chemotaxis, motility, structure, metabolism, gene regulation, plasmid maintenance and replication, etc. The insertion sites of 4480 transposon mutants have been determined. About 800 predicted protein-encoding genes in the genome were disrupted in the STM transposon library. The infectivity and some functions of 800 mutants in 500 genes have been determined. Analysis of these transposon mutants has yielded valuable information regarding the genes and gene products important in the pathogenesis and biology of B. burgdorferi and its tick vectors.
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Williams SK, Weiner ZP, Gilmore RD. Human neuroglial cells internalize Borrelia burgdorferi by coiling phagocytosis mediated by Daam1. PLoS One 2018; 13:e0197413. [PMID: 29746581 PMCID: PMC5944952 DOI: 10.1371/journal.pone.0197413] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/01/2018] [Indexed: 11/18/2022] Open
Abstract
Borrelia burgdorferi, the agent of Lyme borreliosis, can elude hosts’ innate and adaptive immunity as part of the course of infection. The ability of B. burgdorferi to invade or be internalized by host cells in vitro has been proposed as a mechanism for the pathogen to evade immune responses or antimicrobials. We have previously shown that B. burgdorferi can be internalized by human neuroglial cells. In this study we demonstrate that these cells take up B. burgdorferi via coiling phagocytosis mediated by the formin, Daam1, a process similarly described for human macrophages. Following coincubation with glial cells, B. burgdorferi was enwrapped by Daam1-enriched coiling pseudopods. Coiling of B. burgdorferi was significantly reduced when neuroglial cells were pretreated with anti-Daam1 antibody indicating the requirement for Daam1 for borrelial phagocytosis. Confocal microscopy showed Daam1 colocalizing to the B. burgdorferi surface suggesting interaction with borrelial membrane protein(s). Using the yeast 2-hybrid system for identifying protein-protein binding, we found that the B. burgdorferi surface lipoprotein, BBA66, bound the FH2 subunit domain of Daam1. Recombinant proteins were used to validate binding by ELISA, pull-down, and co-immunoprecipitation. Evidence for native Daam1 and BBA66 interaction was suggested by colocalization of the proteins in the course of borrelial capture by the Daam1-enriched pseudopodia. Additionally, we found a striking reduction in coiling for a BBA66-deficient mutant strain compared to BBA66-expressing strains. These results show that coiling phagocytosis is a mechanism for borrelial internalization by neuroglial cells mediated by Daam1.
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Affiliation(s)
- Shanna K. Williams
- Bacterial Diseases Branch, Division of Vector Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | - Zachary P. Weiner
- Bacterial Diseases Branch, Division of Vector Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | - Robert D. Gilmore
- Bacterial Diseases Branch, Division of Vector Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
- * E-mail:
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Casjens SR, Di L, Akther S, Mongodin EF, Luft BJ, Schutzer SE, Fraser CM, Qiu WG. Primordial origin and diversification of plasmids in Lyme disease agent bacteria. BMC Genomics 2018; 19:218. [PMID: 29580205 PMCID: PMC5870499 DOI: 10.1186/s12864-018-4597-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 03/12/2018] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND With approximately one-third of their genomes consisting of linear and circular plasmids, the Lyme disease agent cluster of species has the most complex genomes among known bacteria. We report here a comparative analysis of plasmids in eleven Borreliella (also known as Borrelia burgdorferi sensu lato) species. RESULTS We sequenced the complete genomes of two B. afzelii, two B. garinii, and individual B. spielmanii, B. bissettiae, B. valaisiana and B. finlandensis isolates. These individual isolates carry between seven and sixteen plasmids, and together harbor 99 plasmids. We report here a comparative analysis of these plasmids, along with 70 additional Borreliella plasmids available in the public sequence databases. We identify only one new putative plasmid compatibility type (the 30th) among these 169 plasmid sequences, suggesting that all or nearly all such types have now been discovered. We find that the linear plasmids in the non-B. burgdorferi species have undergone the same kinds of apparently random, chaotic rearrangements mediated by non-homologous recombination that we previously discovered in B. burgdorferi. These rearrangements occurred independently in the different species lineages, and they, along with an expanded chromosomal phylogeny reported here, allow the identification of several whole plasmid transfer events among these species. Phylogenetic analyses of the plasmid partition genes show that a majority of the plasmid compatibility types arose early, most likely before separation of the Lyme agent Borreliella and relapsing fever Borrelia clades, and this, with occasional cross species plasmid transfers, has resulted in few if any species-specific or geographic region-specific Borreliella plasmid types. CONCLUSIONS The primordial origin and persistent maintenance of the Borreliella plasmid types support their functional indispensability as well as evolutionary roles in facilitating genome diversity. The improved resolution of Borreliella plasmid phylogeny based on conserved partition-gene clusters will lead to better determination of gene orthology which is essential for prediction of biological function, and it will provide a basis for inferring detailed evolutionary mechanisms of Borreliella genomic variability including homologous gene and plasmid exchanges as well as non-homologous rearrangements.
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Affiliation(s)
- Sherwood R. Casjens
- Division of Microbiology and Immunology, Pathology Department and Biology Department, University of Utah School of Medicine, Salt Lake City, UT USA
- Biology Department, University of Utah, Salt Lake City, UT USA
- Pathology Department, University of Utah School of Medicine, Room 2200K Emma Eccles Jones Medical Research Building, 15 North Medical Drive East, Salt Lake City, UT 84112 USA
| | - Lia Di
- Department of Biological Sciences and Center for Translational and Basic Research, Hunter College of the City University of New York, New York, NY USA
| | - Saymon Akther
- Department of Biology, The Graduate Center, City University of New York, New York, NY USA
| | - Emmanuel F. Mongodin
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD USA
| | - Benjamin J. Luft
- Department of Medicine, Health Science Center, Stony Brook University, Stony Brook, NY USA
| | - Steven E. Schutzer
- Department of Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ USA
| | - Claire M. Fraser
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD USA
| | - Wei-Gang Qiu
- Department of Biology, The Graduate Center, City University of New York, New York, NY USA
- Department of Biological Sciences and Center for Translational and Basic Research, Hunter College of the City University of New York, New York, NY USA
- Department of Physiology and Biophysics & Institute for Computational Biomedicine, Weil Cornell Medical College, New York, USA
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Abstract
The disciplines of Borrelia (Borreliella) burgdorferi microbiology and Lyme disease pathogenesis have come to depend on the genetic manipulation of the spirochete. Generating mutants in these recalcitrant bacteria, while not straightforward, is routinely accomplished in numerous laboratories, although there are several crucial caveats to consider. This chapter describes the design of basic molecular genetic experiments as well as the detailed methodologies to prepare and transform competent cells, select for and isolate transformants, and complement or genetically restore mutants.
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Affiliation(s)
- D Scott Samuels
- Division of Biological Sciences, University of Montana, Missoula, MT, USA.
| | - Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Laura S Hall
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
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Peptide Uptake Is Essential for Borrelia burgdorferi Viability and Involves Structural and Regulatory Complexity of its Oligopeptide Transporter. mBio 2017; 8:mBio.02047-17. [PMID: 29259089 PMCID: PMC5736914 DOI: 10.1128/mbio.02047-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Borrelia burgdorferi is an extreme amino acid (AA) auxotroph whose genome encodes few free AA transporters and an elaborate oligopeptide transport system (B. burgdorferi Opp [BbOpp]). BbOpp consists of five oligopeptide-binding proteins (OBPs), two heterodimeric permeases, and a heterodimeric nucleotide-binding domain (NBD). Homology modeling based on the crystal structure of liganded BbOppA4 revealed that each OBP likely binds a distinct range of peptides. Transcriptional analyses demonstrated that the OBPs are differentially and independently regulated whereas the permeases and NBDs are constitutively expressed. A conditional NBD mutant failed to divide in the absence of inducer and replicated in an IPTG (isopropyl-β-d-thiogalactopyranoside) concentration-dependent manner. NBD mutants grown without IPTG exhibited an elongated morphotype lacking division septa, often with flattening at the cell center due to the absence of flagellar filaments. Following cultivation in dialysis membrane chambers, NBD mutants recovered from rats not receiving IPTG also displayed an elongated morphotype. The NBD mutant was avirulent by needle inoculation, but infectivity was partially restored by oral administration of IPTG to infected mice. We conclude that peptides are a major source of AAs for B. burgdorferi both in vitro and in vivo and that peptide uptake is essential for regulation of morphogenesis, cell division, and virulence. Borrelia burgdorferi, the causative agent of Lyme disease, is an extreme amino acid (AA) auxotroph with a limited repertoire of annotated single-AA transporters. A major issue is how the spirochete meets its AA requirements as it transits between its arthropod vector and mammalian reservoir. While previous studies have confirmed that the B. burgdorferi oligopeptide transport (opp) system is capable of importing peptides, the importance of the system for viability and pathogenesis has not been established. Here, we evaluated the opp system structurally and transcriptionally to elucidate its ability to import a wide range of peptides during the spirochete’s enzootic cycle. Additionally, using a novel mutagenesis strategy to abrogate opp transporter function, we demonstrated that peptide uptake is essential for bacterial viability, morphogenesis, and infectivity. Our studies revealed a novel link between borrelial physiology and virulence and suggest that peptide uptake serves an intracellular signaling function regulating morphogenesis and division.
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Aslam B, Nisar MA, Khurshid M, Farooq Salamat MK. Immune escape strategies of Borrelia burgdorferi. Future Microbiol 2017; 12:1219-1237. [PMID: 28972415 DOI: 10.2217/fmb-2017-0013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The borrelial resurge demonstrates that Borrelia burgdorferi is a persistent health problem. This spirochete is responsible for a global public health concern called Lyme disease. B. burgdorferi faces diverse environmental conditions of its vector and host during its life cycle. To circumvent the host immune system is a prominent feature of B. burgdorferi. To date, numerous studies have reported on the various mechanisms used by this pathogen to evade the host defense mechanisms. This current review attempts to consolidate this information to describe the immunological and molecular methods used by B. burgdorferi for its survival.
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Affiliation(s)
- Bilal Aslam
- Department of Microbiology, Government College University, Faisalabad, Pakistan
| | - Muhammad Atif Nisar
- Department of Microbiology, Government College University, Faisalabad, Pakistan
| | - Mohsin Khurshid
- Department of Microbiology, Government College University, Faisalabad, Pakistan.,College of Allied Health Professionals, Directorate of Medical Sciences, Government College University, Faisalabad, Pakistan
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Two Distinct Mechanisms Govern RpoS-Mediated Repression of Tick-Phase Genes during Mammalian Host Adaptation by Borrelia burgdorferi, the Lyme Disease Spirochete. mBio 2017; 8:mBio.01204-17. [PMID: 28830947 PMCID: PMC5565969 DOI: 10.1128/mbio.01204-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The alternative sigma factor RpoS plays a key role modulating gene expression in Borrelia burgdorferi, the Lyme disease spirochete, by transcribing mammalian host-phase genes and repressing σ70-dependent genes required within the arthropod vector. To identify cis regulatory elements involved in RpoS-dependent repression, we analyzed green fluorescent protein (GFP) transcriptional reporters containing portions of the upstream regions of the prototypical tick-phase genes ospAB, the glp operon, and bba74. As RpoS-mediated repression occurs only following mammalian host adaptation, strains containing the reporters were grown in dialysis membrane chambers (DMCs) implanted into the peritoneal cavities of rats. Wild-type spirochetes harboring ospAB- and glp-gfp constructs containing only the minimal (−35/−10) σ70 promoter elements had significantly lower expression in DMCs relative to growth in vitro at 37°C; no reduction in expression occurred in a DMC-cultivated RpoS mutant harboring these constructs. In contrast, RpoS-mediated repression of bba74 required a stretch of DNA located between −165 and −82 relative to its transcriptional start site. Electrophoretic mobility shift assays employing extracts of DMC-cultivated B. burgdorferi produced a gel shift, whereas extracts from RpoS mutant spirochetes did not. Collectively, these data demonstrate that RpoS-mediated repression of tick-phase borrelial genes occurs by at least two distinct mechanisms. One (e.g., ospAB and the glp operon) involves primarily sequence elements near the core promoter, while the other (e.g., bba74) involves an RpoS-induced transacting repressor. Our results provide a genetic framework for further dissection of the essential “gatekeeper” role of RpoS throughout the B. burgdorferi enzootic cycle. Borrelia burgdorferi, the Lyme disease spirochete, modulates gene expression to adapt to the distinctive environments of its mammalian host and arthropod vector during its enzootic cycle. The alternative sigma factor RpoS has been referred to as a “gatekeeper” due to its central role in regulating the reciprocal expression of mammalian host- and tick-phase genes. While RpoS-dependent transcription has been studied extensively, little is known regarding the mechanism(s) of RpoS-mediated repression. We employed a combination of green fluorescent protein transcriptional reporters along with an in vivo model to define cis regulatory sequences responsible for RpoS-mediated repression of prototypical tick-phase genes. Repression of ospAB and the glp operon requires only sequences near their core promoters, whereas modulation of bba74 expression involves a putative RpoS-dependent repressor that binds upstream of the core promoter. Thus, Lyme disease spirochetes employ at least two different RpoS-dependent mechanisms to repress tick-phase genes within the mammal.
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A high-throughput genetic screen identifies previously uncharacterized Borrelia burgdorferi genes important for resistance against reactive oxygen and nitrogen species. PLoS Pathog 2017; 13:e1006225. [PMID: 28212410 PMCID: PMC5333916 DOI: 10.1371/journal.ppat.1006225] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 03/02/2017] [Accepted: 02/08/2017] [Indexed: 02/06/2023] Open
Abstract
Borrelia burgdorferi, the causative agent of Lyme disease in humans, is exposed to reactive oxygen and nitrogen species (ROS and RNS) in both the tick vector and vertebrate reservoir hosts. B. burgdorferi contains a limited repertoire of canonical oxidative stress response genes, suggesting that novel gene functions may be important for protection of B. burgdorferi against ROS or RNS exposure. Here, we use transposon insertion sequencing (Tn-seq) to conduct an unbiased search for genes involved in resistance to nitric oxide, hydrogen peroxide, and tertiary-butyl hydroperoxide in vitro. The screens identified 66 genes whose disruption resulted in increased susceptibility to at least one of the stressors. These genes include previously characterized mediators of ROS and RNS resistance (including components of the nucleotide excision repair pathway and a subunit of a riboflavin transporter), as well as novel putative resistance candidates. DNA repair mutants were among the most sensitive to RNS in the Tn-seq screen, and survival assays with individual Tn mutants confirmed that the putative ribonuclease BB0839 is involved in resistance to nitric oxide. In contrast, mutants lacking predicted inner membrane proteins or transporters were among the most sensitive to ROS, and the contribution of three such membrane proteins (BB0017, BB0164, and BB0202) to ROS sensitivity was confirmed using individual Tn mutants and complemented strains. Further analysis showed that levels of intracellular manganese are significantly reduced in the Tn::bb0164 mutant, identifying a novel role for BB0164 in B. burgdorferi manganese homeostasis. Infection of C57BL/6 and gp91phox-/- mice with a mini-library of 39 Tn mutants showed that many of the genes identified in the in vitro screens are required for infectivity in mice. Collectively, our data provide insight into how B. burgdorferi responds to ROS and RNS and suggests that this response is relevant to the in vivo success of the organism.
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Outer Membrane Proteins BB0405 and BB0406 Are Immunogenic, but Only BB0405 Is Required for Borrelia burgdorferi Infection. Infect Immun 2017; 85:IAI.00803-16. [PMID: 27920211 DOI: 10.1128/iai.00803-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 11/24/2016] [Indexed: 02/06/2023] Open
Abstract
We recently identified the Borrelia burgdorferi outer membrane protein (OMP) BB0406 and found that the gene encoding this OMP was cotranscribed with the gene encoding the OMP BB0405. Interestingly, BB0405 and BB0406 share 59% similarity and are grouped into the same B. burgdorferi paralogous gene family. Given their overall similarity, it is plausible that both OMPs have similar or overlapping functions in this pathogenic spirochete. BB0405 was recently shown to be required for mammalian infection despite the observations that BB0405 is poorly immunogenic and not recognized during mouse or human infection. BB0405 orthologs have also been shown to bind the complement regulator protein factor H. Therefore, to better elucidate the role of BB0405 and its paralog BB0406 during infection and in serum resistance, we examined both proteins in animal infection, factor H binding, and serum sensitivity assays. Our combined results suggest that BB0405- and BB0406-specific antibodies are borreliacidal and that both OMPs are immunogenic during nonhuman primate infection. Additionally, while BB0405 was found to be required for establishing mouse infection, BB0406 was not found to be essential for infectivity. In contrast to data from previous reports, however, neither OMP was found to bind human factor H or to be required for enhancing serum resistance of B. burgdorferi in vitro.
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Antibody Response to Lyme Disease Spirochetes in the Context of VlsE-Mediated Immune Evasion. Infect Immun 2016; 85:IAI.00890-16. [PMID: 27799330 DOI: 10.1128/iai.00890-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 10/20/2016] [Indexed: 12/31/2022] Open
Abstract
Lyme disease (LD), the most prevalent tick-borne illness in North America, is caused by Borrelia burgdorferi The long-term survival of B. burgdorferi spirochetes in the mammalian host is achieved though VlsE-mediated antigenic variation. It is mathematically predicted that a highly variable surface antigen prolongs bacterial infection sufficiently to exhaust the immune response directed toward invariant surface antigens. If the prediction is correct, it is expected that the antibody response to B. burgdorferi invariant antigens will become nonprotective as B. burgdorferi infection progresses. To test this assumption, changes in the protective efficacy of the immune response to B. burgdorferi surface antigens were monitored via a superinfection model over the course of 70 days. B. burgdorferi-infected mice were subjected to secondary challenge by heterologous B. burgdorferi at different time points postinfection (p.i.). When the infected mice were superinfected with a VlsE-deficient clone (ΔVlsE) at day 28 p.i., the active anti-B. burgdorferi immune response did not prevent ΔVlsE-induced spirochetemia. In contrast, most mice blocked culture-detectable spirochetemia induced by wild-type B. burgdorferi (WT), indicating that VlsE was likely the primary target of the antibody response. As the B. burgdorferi infection further progressed, however, reversed outcomes were observed. At day 70 p.i. the host immune response to non-VlsE antigens became sufficiently potent to clear spirochetemia induced by ΔVlsE and yet failed to prevent WT-induced spirochetemia. To test if any significant changes in the anti-B. burgdorferi antibody repertoire accounted for the observed outcomes, global profiles of antibody specificities were determined. However, comparison of mimotopes revealed no major difference between day 28 and day 70 antibody repertoires.
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Eggers CH, Gray CM, Preisig AM, Glenn DM, Pereira J, Ayers RW, Alshahrani M, Acabbo C, Becker MR, Bruenn KN, Cheung T, Jendras TM, Shepley AB, Moeller JT. Phage-mediated horizontal gene transfer of both prophage and heterologous DNA by ϕBB-1, a bacteriophage of Borrelia burgdorferi. Pathog Dis 2016; 74:ftw107. [PMID: 27811049 DOI: 10.1093/femspd/ftw107] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/25/2016] [Accepted: 10/28/2016] [Indexed: 11/13/2022] Open
Abstract
Horizontal gene transfer (HGT) in Borrelia burgdorferi, the Lyme disease agent, is likely mediated by bacteriophage. Studies of the B. burgdorferi phage, ϕBB-1 and its role in HGT have been hindered by the lack of an assay for readily characterizing phage-mediated DNA movement (transduction). Here we describe an in vitro assay in which a clone of B. burgdorferi strain CA-11.2A encoding kanamycin resistance on a ϕBB-1 prophage is co-cultured with different clones encoding gentamicin resistance on a shuttle vector; transduction is monitored by enumerating colonies selected in the presence of both kanamycin and gentamicin. When both clones used in the assay were derived from CA-11.2A, the frequency of transduction was 1.23 × 10-6 transductants per cell, and could be increased 5-fold by exposing the phage-producing strain to 5% ethanol. Transduction was also demonstrated between the CA-11.2A clone and clones of both high-passage B. burgdorferi strain B31 and low-passage, virulent B. burgdorferi strain 297, although with lower transduction frequencies. The transductant in the 297 background produced phage capable of transducing another B. burgdorferi clone: this is the first experimental demonstration of transduction from a clone of a virulent strain. In addition to prophage DNA, small Escherichia coli-derived shuttle vectors were also transduced between co-cultured B. burgdorferi strains, suggesting both a broad role for the phage in the HGT of heterologous DNA and a potential use of the phage as a molecular tool. These results enhance our understanding of phage-mediated transduction as a mechanism of HGT in the Lyme disease spirochetes. Furthermore, the reagents and techniques developed herein will facilitate future studies of phage-mediated HGT, especially within the tick vector and vertebrate host.
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Affiliation(s)
- Christian H Eggers
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Carlie M Gray
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Alexander M Preisig
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Danielle M Glenn
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Jessica Pereira
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Ryan W Ayers
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Mohammad Alshahrani
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Christopher Acabbo
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Maria R Becker
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Kimberly N Bruenn
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Timothy Cheung
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Taylor M Jendras
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Aron B Shepley
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - John T Moeller
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA
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Troy EB, Lin T, Gao L, Lazinski DW, Lundt M, Camilli A, Norris SJ, Hu LT. Global Tn-seq analysis of carbohydrate utilization and vertebrate infectivity of Borrelia burgdorferi. Mol Microbiol 2016; 101:1003-23. [PMID: 27279039 DOI: 10.1111/mmi.13437] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 06/07/2016] [Indexed: 02/05/2023]
Abstract
Borrelia burgdorferi maintains a complex life cycle between tick and vertebrate hosts. Although some genes have been identified as contributing to bacterial adaptation in the different hosts, the list is incomplete. In this manuscript, we report the first use of transposon mutagenesis combined with high-throughput sequencing (Tn-seq) in B. burgdorferi. We utilize the technique to investigate mechanisms of carbohydrate utilization in B. burgdorferi and the role of carbohydrate metabolism during mouse infection. We performed genetic fitness analyses to identify genes encoding factors contributing to growth on glucose, maltose, mannose, trehalose and N-acetyl-glucosamine. We obtained insight into the potential functions of proteins predicted to be involved in carbohydrate utilization and identified additional factors previously unrecognized as contributing to the metabolism of the tested carbohydrates. Strong phenotypes were observed for the putative carbohydrate phosphotransferase transporters BB0408 and BBB29 as well as the response regulator Rrp1. We further validated Tn-seq for use in mouse studies and were able to correctly identify known infectivity factors as well as additional transporters and genes on lp54 that may contribute to optimal mouse infection. As such, this study establishes Tn-seq as a powerful method for both in vitro and in vivo studies of B. burgdorferi.
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Affiliation(s)
- Erin B Troy
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA
| | - Tao Lin
- Department of Pathology and Laboratory Medicine, University of Texas Medical Center at Houston, Houston, TX
| | - Lihui Gao
- Department of Pathology and Laboratory Medicine, University of Texas Medical Center at Houston, Houston, TX
| | - David W Lazinski
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA
| | - Maureen Lundt
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA
| | - Andrew Camilli
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA.,Howard Hughes Medical Institute, Boston, MA
| | - Steven J Norris
- Department of Pathology and Laboratory Medicine, University of Texas Medical Center at Houston, Houston, TX.,Department of Microbiology and Molecular Genetics, University of Texas Medical Center at Houston, Houston, TX
| | - Linden T Hu
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA.
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Casselli T, Bankhead T. Use of in vivo Expression Technology for the Identification of Putative Host Adaptation Factors of the Lyme Disease Spirochete. J Mol Microbiol Biotechnol 2015; 25:349-61. [PMID: 26488479 DOI: 10.1159/000439305] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The causative agent of Lyme disease, Borrelia burgdorferi, is an obligate parasite that requires either a tick vector or a mammalian host for survival. Identification of the bacterial genes that are specifically expressed during infection of the mammalian host could provide targets for novel therapeutics and vaccines. In vivo expression technology (IVET) is a reporter-based promoter trap system that utilizes selectable markers to identify promoters of bacterial host-specific genes. Using previously characterized genes for in vivo and in vitro selection, this study utilized an IVET system that allows for selection of B. burgdorferi sequences that act as active promoters only during murine infection. This promoter trap system was able to successfully distinguish active promoter sequences both in vivo and in vitro from control sequences and a library of cloned B. burgdorferi genomic fragments. However, a bottleneck effect during the experimental mouse infection limited the utility for genome-wide promoter screening. Overall, IVET was demonstrated as a tool for the identification of in vivo-induced promoter elements of B. burgdorferi, and the observed infection bottleneck apparent using a polyclonal infection pool provides insight into the dynamics of experimental infection with B. burgdorferi.
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Affiliation(s)
- Timothy Casselli
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Wash., USA
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Long-term survival of Borrelia burgdorferi lacking the hibernation promotion factor homolog in the unfed tick vector. Infect Immun 2015; 83:4800-10. [PMID: 26438790 DOI: 10.1128/iai.00925-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/21/2015] [Indexed: 11/20/2022] Open
Abstract
Borrelia burgdorferi, a causative agent of Lyme borreliosis, is a zoonotic pathogen that survives in nutrient-limited environments within a tick, prior to transmission to its mammalian host. Survival under these prolonged nutrient-limited conditions is thought to be similar to survival during stationary phase, which is characterized by growth cessation and decreased protein production. Multiple ribosome-associated proteins are implicated in stationary-phase survival of Escherichia coli. These proteins include hibernation-promoting factor (HPF), which dimerizes ribosomes and prevents translation of mRNA. Bioinformatic analyses indicate that B. burgdorferi harbors an hpf homolog, the bb0449 gene. BB0449 protein secondary structure modeling also predicted HPF-like structure and function. However, BB0449 protein was not localized in the ribosome-associated protein fraction of in vitro-grown B. burgdorferi. In wild-type B. burgdorferi, bb0449 transcript and BB0449 protein levels are low during various growth phases. These results are inconsistent with patterns of synthesis of HPF-like proteins in other bacterial species. In addition, two independently derived bb0449 mutants successfully completed the mouse-tick infectious cycle, indicating that bb0449 is not required for prolonged survival in the nutrient-limited environment in the unfed tick or any other stage of infection by B. burgdorferi. We suggest either that BB0449 is associated with ribosomes under specific conditions not yet identified or that BB0449 of B. burgdorferi has a function other than ribosome conformation modulation.
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Borrelia burgdorferi elongation factor EF-Tu is an immunogenic protein during Lyme borreliosis. Emerg Microbes Infect 2015; 4:e54. [PMID: 26954993 PMCID: PMC5176084 DOI: 10.1038/emi.2015.54] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 07/17/2015] [Accepted: 07/21/2015] [Indexed: 12/22/2022]
Abstract
Borrelia burgdorferi, the etiological agent of Lyme disease, does not produce lipopolysaccharide but expresses a large number of lipoproteins on its cell surface. These outer membrane lipoproteins are highly immunogenic and have been used for serodiagnosis of Lyme disease. Recent studies have shown that highly conserved cytosolic proteins such as enolase and elongation factor Tu (EF-Tu) unexpectedly localized on the surface of bacteria including B. burgdorferi, and surface-localized enolase has shown to contribute to the enzootic cycle of B. burgdorferi. In this study, we studied the immunogenicity, surface localization, and function of B. burgdorferi EF-Tu. We found that EF-Tu is highly immunogenic in mice, and EF-Tu antibodies were readily detected in Lyme disease patients. On the other hand, active immunization studies showed that EF-Tu antibodies did not protect mice from infection when challenged with B. burgdorferi via either needle inoculation or tick bites. Borrelial mouse-tick cycle studies showed that EF-Tu antibodies also did not block B. burgdorferi migration and survival in ticks. Consistent with these findings, we found that EF-Tu primarily localizes in the protoplasmic cylinder of spirochetes and is not on the surface of B. burgdorferi. Taken together, our studies suggest that B. burgdorferi EF-Tu is not surfaced exposed, but it is highly immunogenic and is a potential serodiagnostic marker for Lyme borreliosis.
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BB0744 Affects Tissue Tropism and Spatial Distribution of Borrelia burgdorferi. Infect Immun 2015; 83:3693-703. [PMID: 26150534 DOI: 10.1128/iai.00828-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 06/29/2015] [Indexed: 12/18/2022] Open
Abstract
Borrelia burgdorferi, the etiologic agent of Lyme disease, produces a variety of proteins that promote survival and colonization in both the Ixodes species vector and various mammalian hosts. We initially identified BB0744 (also known as p83/100) by screening for B. burgdorferi strain B31 proteins that bind to α1β1 integrin and hypothesized that, given the presence of a signal peptide, BB0744 may be a surface-exposed protein. In contrast to this expectation, localization studies suggested that BB0744 resides in the periplasm. Despite its subsurface location, we were interested in testing whether BB0744 is required for borrelial pathogenesis. To this end, a bb0744 deletion was isolated in a B. burgdorferi strain B31 infectious background, complemented, and queried for the role of BB0744 following experimental infection. A combination of bioluminescent imaging, cultivation of infected tissues, and quantitative PCR (qPCR) demonstrated that Δbb0744 mutant B. burgdorferi bacteria were attenuated in the ability to colonize heart tissue, as well as skin locations distal to the site of infection. Furthermore, qPCR indicated a significantly reduced spirochetal load in distal skin and joint tissue infected with Δbb0744 mutant B. burgdorferi. Complementation with bb0744 restored infectivity, indicating that the defect seen in Δbb0744 mutant B. burgdorferi was due to the loss of BB0744. Taken together, these results suggest that BB0744 is necessary for tissue tropism, particularly in heart tissue, alters the ability of B. burgdorferi to disseminate efficiently, or both. Additional studies are warranted to address the mechanism employed by BB0744 that alters the pathogenic potential of B. burgdorferi.
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Chan K, Alter L, Barthold SW, Parveen N. Disruption of bbe02 by Insertion of a Luciferase Gene Increases Transformation Efficiency of Borrelia burgdorferi and Allows Live Imaging in Lyme Disease Susceptible C3H Mice. PLoS One 2015; 10:e0129532. [PMID: 26069970 PMCID: PMC4466376 DOI: 10.1371/journal.pone.0129532] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 05/11/2015] [Indexed: 12/25/2022] Open
Abstract
Lyme disease is the most prevalent tick-borne disease in North America and Europe. The causative agent, Borrelia burgdorferi persists in the white-footed mouse. Infection with B. burgdorferi can cause acute to persistent multisystemic Lyme disease in humans. Some disease manifestations are also exhibited in the mouse model of Lyme disease. Genetic manipulation of B. burgdorferi remains difficult. First, B. burgdorferi contains a large number of endogenous plasmids with unique sequences encoding unknown functions. The presence of these plasmids needs to be confirmed after each genetic manipulation. Second, the restriction modification defense systems, including that encoded by bbe02 gene lead to low transformation efficiency in B. burgdorferi. Therefore, studying the molecular basis of Lyme pathogenesis is a challenge. Furthermore, investigation of the role of a specific B. burgdorferi protein throughout infection requires a large number of mice, making it labor intensive and expensive. To overcome the problems associated with low transformation efficiency and to reduce the number of mice needed for experiments, we disrupted the bbe02 gene of a highly infectious and pathogenic B. burgdorferi strain, N40 D10/E9 through insertion of a firefly luciferase gene. The bbe02 mutant shows higher transformation efficiency and maintains luciferase activity throughout infection as detected by live imaging of mice. Infectivity and pathogenesis of this mutant were comparable to the wild-type N40 strain. This mutant will serve as an ideal parental strain to examine the roles of various B. burgdorferi proteins in Lyme pathogenesis in the mouse model in the future.
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Affiliation(s)
- Kamfai Chan
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, 07103, United States of America
| | - Laura Alter
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, 07103, United States of America
| | - Stephen W. Barthold
- Department of Pathology, Microbiology & Immunology, University of California School of Veterinary Medicine, Davis, CA, 95616, United States of America
| | - Nikhat Parveen
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, 07103, United States of America
- * E-mail:
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