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Foor SD, Brangulis K, Shakya AK, Rana VS, Bista S, Kitsou C, Ronzetti M, Alreja AB, Linden SB, Altieri AS, Baljinnyam B, Akopjana I, Nelson DC, Simeonov A, Herzberg O, Caimano MJ, Pal U. A unique borrelial protein facilitates microbial immune evasion. mBio 2023; 14:e0213523. [PMID: 37830812 PMCID: PMC10653885 DOI: 10.1128/mbio.02135-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 08/14/2023] [Indexed: 10/14/2023] Open
Abstract
IMPORTANCE Lyme disease is a major tick-borne infection caused by a bacterial pathogen called Borrelia burgdorferi, which is transmitted by ticks and affects hundreds of thousands of people every year. These bacterial pathogens are distinct from other genera of microbes because of their distinct features and ability to transmit a multi-system infection to a range of vertebrates, including humans. Progress in understanding the infection biology of Lyme disease, and thus advancements towards its prevention, are hindered by an incomplete understanding of the microbiology of B. burgdorferi, partly due to the occurrence of many unique borrelial proteins that are structurally unrelated to proteins of known functions yet are indispensable for pathogen survival. We herein report the use of diverse technologies to examine the structure and function of a unique B. burgdorferi protein, annotated as BB0238-an essential virulence determinant. We show that the protein is structurally organized into two distinct domains, is involved in multiplex protein-protein interactions, and facilitates tick-to-mouse pathogen transmission by aiding microbial evasion of early host cellular immunity. We believe that our findings will further enrich our understanding of the microbiology of B. burgdorferi, potentially impacting the future development of novel prevention strategies against a widespread tick-transmitted infection.
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Affiliation(s)
- Shelby D. Foor
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
| | - Kalvis Brangulis
- Latvian Biomedical Research and Study Centre, Riga, Latvia
- Department of Human Physiology and Biochemistry, Riga Stradins University, Riga, Latvia
| | - Anil K. Shakya
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland, USA
| | - Vipin S. Rana
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
| | - Sandhya Bista
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
| | - Chrysoula Kitsou
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
| | - Michael Ronzetti
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Adit B. Alreja
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland, USA
| | - Sara B. Linden
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland, USA
| | - Amanda S. Altieri
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland, USA
| | - Bolormaa Baljinnyam
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Inara Akopjana
- Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Daniel C. Nelson
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland, USA
| | - Anton Simeonov
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Osnat Herzberg
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland, USA
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, USA
| | - Melissa J. Caimano
- Departments of Medicine, Pediatrics, and Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
- Virginia-Maryland College of Veterinary Medicine, College Park, Maryland, USA
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Yang L, Zhang X, Chen W, Seña AC, Zheng H, Jiang Y, Zhao P, Chen R, Wang L, Ke W, Salazar JC, Parr JB, Tucker JD, Hawley KL, Caimano MJ, Hennelly CM, Aghakanian F, Zhang F, Chen JS, Moody MA, Radolf JD, Yang B. Early syphilis in Guangzhou, China: presentation, molecular detection of Treponema pallidum , and genomic sequences in clinical specimens and isolates obtained by rabbit infectivity testing. medRxiv 2023:2023.10.17.23297169. [PMID: 37905017 PMCID: PMC10614984 DOI: 10.1101/2023.10.17.23297169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Background The global resurgence of syphilis requires novel prevention strategies. Whole genome sequencing (WGS) of Treponema pallidum ( TPA ) using different specimen types is essential for vaccine development. Methods Patients with primary (PS) and secondary (SS) syphilis were recruited in Guangzhou, China. We collected ulcer exudates and blood from PS participants, and skin biopsies and blood from SS participants for TPA polA polymerase chain reaction (PCR); ulcer exudates and blood were also used to isolate TPA strains by rabbit infectivity testing (RIT). TPA WGS was performed on 52 ulcer exudates and biopsy specimens and 25 matched rabbit isolates. Results We enrolled 18 PS and 51 SS participants from December 2019 to March 2022. Among PS participants, TPA DNA was detected in 16 (89%) ulcer exudates and three (17%) blood specimens. Among SS participants, TPA DNA was detected in 50 (98%) skin biopsies and 27 (53%) blood specimens. TP A was isolated from 48 rabbits, with a 71% (12/17) success rate from ulcer exudates and 69% (36/52) from SS bloods. Twenty-three matched SS14 clade genomes were virtually identical, while two Nichols clade pairs had discordant tprK sequences. Forty-two of 52 unique TPA genomes clustered in an SS14 East Asia subgroup, while ten fell into two East Asian Nichols subgroups. Conclusions Our TPA detection rate was high from PS ulcer exudates and SS skin biopsies and over 50% from SS whole blood, with RIT isolation in over two-thirds of samples. Our results support the use of WGS from rabbit isolates to inform vaccine development. Summary We performed Treponema pallidum molecular detection and genome sequencing from multiple specimens collected from early syphilis patients and isolates obtained by rabbit inoculation. Our results support the use of whole genome sequencing from rabbit isolates to inform syphilis vaccine development.
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Ferguson MR, Delgado KN, McBride S, Orbe IC, La Vake CJ, Caimano MJ, Mendez Q, Moraes TF, Schryvers AB, Moody MA, Radolf JD, Weiner MP, Hawley KL. Use of Epivolve phage display to generate a monoclonal antibody with opsonic activity directed against a subdominant epitope on extracellular loop 4 of Treponema pallidum BamA (TP0326). Front Immunol 2023; 14:1222267. [PMID: 37675118 PMCID: PMC10478084 DOI: 10.3389/fimmu.2023.1222267] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Accepted: 07/19/2023] [Indexed: 09/08/2023] Open
Abstract
Introduction Syphilis, a sexually transmitted infection caused by the spirochete Treponema pallidum (Tp), is resurging globally. Tp's repertoire of outer membrane proteins (OMPs) includes BamA (β-barrel assembly machinery subunit A/TP0326), a bipartite protein consisting of a 16-stranded β-barrel with nine extracellular loops (ECLs) and five periplasmic POTRA (polypeptide transport-associated) domains. BamA ECL4 antisera promotes internalization of Tp by rabbit peritoneal macrophages. Methods Three overlapping BamA ECL4 peptides and a two-stage, phage display strategy, termed "Epivolve" (for epitope evolution) were employed to generate single-chain variable fragments (scFvs). Additionally, antisera generated by immunizing mice and rabbits with BamA ECL4 displayed by a Pyrococcus furiosus thioredoxin scaffold (PfTrxBamA/ECL4). MAbs and antisera reactivities were evaluated by immunoblotting and ELISA. A comparison of murine and rabbit opsonophagocytosis assays was conducted to evaluate the functional ability of the Abs (e.g., opsonization) and validate the mouse assay. Sera from Tp-infected mice (MSS) and rabbits (IRS) were evaluated for ECL4-specific Abs using PfTrxBamA/ECL4 and overlapping ECL4 peptides in immunoblotting and ELISA assays. Results Each of the five mAbs demonstrated reactivity by immunoblotting and ELISA to nanogram amounts of PfTrxBamA/ECL4. One mAb, containing a unique amino acid sequence in both the light and heavy chains, showed activity in the murine opsonophagocytosis assay. Mice and rabbits hyperimmunized with PfTrxBamA/ECL4 produced opsonic antisera that strongly recognized the ECL presented in a heterologous scaffold and overlapping ECL4 peptides, including S2. In contrast, Abs generated during Tp infection of mice and rabbits poorly recognized the peptides, indicating that S2 contains a subdominant epitope. Discussion Epivolve produced mAbs target subdominant opsonic epitopes in BamA ECL4, a top syphilis vaccine candidate. The murine opsonophagocytosis assay can serve as an alternative model to investigate the opsonic potential of vaccinogens. Detailed characterization of BamA ECL4-specific Abs provided a means to dissect Ab responses elicited by Tp infection.
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Affiliation(s)
- Mary R. Ferguson
- Department of Molecular Sciences, Abbratech, Branford, CT, United States
| | | | | | - Isabel C. Orbe
- Department of Pediatrics, UConn Health, Farmington, CT, United States
| | - Carson J. La Vake
- Department of Pediatrics, UConn Health, Farmington, CT, United States
| | - 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
| | - Qiana Mendez
- Department of Molecular Sciences, Abbratech, Branford, CT, United States
| | - Trevor F. Moraes
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Anthony B. Schryvers
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada
| | - M. Anthony Moody
- Duke Human Vaccine Institute, Durham, NC, United States
- Department of Pediatrics, Duke University Medical Center, Durham, NC, United States
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC, 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 Immunology, UConn Health, Farmington, CT, United States
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, United States
| | - Michael P. Weiner
- Department of Molecular Sciences, Abbratech, Branford, CT, United States
| | - Kelly L. Hawley
- Department of Medicine, UConn Health, Farmington, CT, United States
- Department of Pediatrics, UConn Health, Farmington, CT, United States
- Department of Immunology, UConn Health, Farmington, CT, United States
- Division of Infectious Diseases and Immunology, Connecticut Children’s, Hartford, CT, United States
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Seña AC, Matoga MM, Yang L, Lopez-Medina E, Aghakanian F, Chen JS, Bettin EB, Caimano MJ, Chen W, Garcia-Luna JA, Hennelly CM, Jiang Y, Juliano JJ, Pospíšilová P, Ramirez L, Šmajs D, Tucker JD, Cely FV, Zheng H, Hoffman IF, Yang B, Moody MA, Hawley KL, Salazar JC, Radolf JD, Parr JB. Clinical and genomic diversity of Treponema pallidum subsp. pallidum: A global, multi-center study of early syphilis to inform vaccine research. medRxiv 2023:2023.07.19.23291250. [PMID: 37546832 PMCID: PMC10402240 DOI: 10.1101/2023.07.19.23291250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Background The continuing increase in syphilis rates worldwide necessitates development of a vaccine with global efficacy. We conducted a multi-center, observational study to explore Treponema pallidum subsp. pallidum ( TPA ) molecular epidemiology essential for vaccine research by analyzing clinical data and specimens from early syphilis patients using whole-genome sequencing (WGS) and publicly available WGS data. Methods We enrolled patients with primary (PS), secondary (SS) or early latent (ELS) syphilis from clinics in China, Colombia, Malawi and the United States between November 2019 - May 2022. Inclusion criteria included age ≥18 years, and syphilis confirmation by direct detection methods and/or serological testing. TPA detection and WGS were conducted on lesion swabs, skin biopsies/scrapings, whole blood, and/or rabbit-passaged isolates. We compared our WGS data to publicly available genomes, and analysed TPA populations to identify mutations associated with lineage and geography. Findings We screened 2,820 patients and enrolled 233 participants - 77 (33%) with PS, 154 (66%) with SS, and two (1%) with ELS. Median age of participants was 28; 66% were cis -gender male, of which 43% reported identifying as "gay", "bisexual", or "other sexuality". Among all participants, 56 (24%) had HIV co-infection. WGS data from 113 participants demonstrated a predominance of SS14-lineage strains with geographic clustering. Phylogenomic analysis confirmed that Nichols-lineage strains are more genetically diverse than SS14-lineage strains and cluster into more distinct subclades. Differences in single nucleotide variants (SNVs) were evident by TPA lineage and geography. Mapping of highly differentiated SNVs to three-dimensional protein models demonstrated population-specific substitutions, some in outer membrane proteins (OMPs) of interest. Interpretation Our study involving participants from four countries substantiates the global diversity of TPA strains. Additional analyses to explore TPA OMP variability within strains will be vital for vaccine development and improved understanding of syphilis pathogenesis on a population level. Funding National Institutes of Health, Bill and Melinda Gates Foundation.
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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 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Coleman S, Unterhauser K, Rezaul K, Ledala N, Lesmes S, Caimano MJ, Zhou Y, Jackson E, Gratalo D, Driscoll MD, Matson AP. High-resolution microbiome analysis reveals exclusionary Klebsiella species competition in preterm infants at risk for necrotizing enterocolitis. Sci Rep 2023; 13:7893. [PMID: 37193703 DOI: 10.1038/s41598-023-34735-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 05/06/2023] [Indexed: 05/18/2023] Open
Abstract
Intestinal colonization with Klebsiella has been linked to necrotizing enterocolitis (NEC), but methods of analysis usually failed to discriminate Klebsiella species or strains. A novel ~ 2500-base amplicon (StrainID) that spans the 16S and 23S rRNA genes was used to generate amplicon sequence variant (ASV) fingerprints for Klebsiella oxytoca and Klebsiella pneumoniae species complexes (KoSC and KpSC, respectively) and co-occurring fecal bacterial strains from 10 preterm infants with NEC and 20 matched controls. Complementary approaches were used to identify cytotoxin-producing isolates of KoSC. Klebsiella species colonized most preterm infants, were more prevalent in NEC subjects versus controls, and replaced Escherichia in NEC subjects. Single KoSC or KpSC ASV fingerprinted strains dominated the gut microbiota, suggesting exclusionary Klebsiella competition for luminal resources. Enterococcus faecalis was co-dominant with KoSC but present infrequently with KpSC. Cytotoxin-producing KoSC members were identified in most NEC subjects and were less frequent in controls. Few Klebsiella strains were shared between subjects. We conclude that inter-species Klebsiella competition, within an environment of KoSC and E. faecalis cooperation, appears to be an important factor for the development of NEC. Preterm infants seem to acquire Klebsiella primarily through routes other than patient-to-patient transmission.
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Affiliation(s)
- Spencer Coleman
- Department of Pediatrics, UConn Health, Farmington, CT, USA
- University of Connecticut School of Medicine, 263 Farmington Avenue, Farmington, CT, 06030, USA
| | | | - Karim Rezaul
- Department of Pediatrics, UConn Health, Farmington, CT, USA
| | | | - Stephanie Lesmes
- Department of Research, Connecticut Children's Medical Center, Hartford, CT, USA
| | - Melissa J Caimano
- Department of Pediatrics, UConn Health, Farmington, CT, USA
- Department of Medicine, UConn Health, Farmington, CT, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, USA
| | - Yanjiao Zhou
- Department of Medicine, UConn Health, Farmington, CT, USA
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | | | | | | | - Adam P Matson
- Department of Pediatrics, UConn Health, Farmington, CT, USA.
- Division of Neonatology, Connecticut Children's Medical Center, Hartford, CT, USA.
- Department of Immunology, UConn Health, Farmington, CT, USA.
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7
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Grassmann AA, Tokarz R, Golino C, McLain MA, Groshong AM, Radolf JD, Caimano MJ. BosR and PlzA reciprocally regulate RpoS function to sustain Borrelia burgdorferi in ticks and mammals. J Clin Invest 2023; 133:e166710. [PMID: 36649080 PMCID: PMC9974103 DOI: 10.1172/jci166710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/10/2023] [Indexed: 01/18/2023] Open
Abstract
The RNA polymerase alternative σ factor RpoS in Borrelia burgdorferi (Bb), the Lyme disease pathogen, is responsible for programmatic-positive and -negative gene regulation essential for the spirochete's dual-host enzootic cycle. RpoS is expressed during tick-to-mammal transmission and throughout mammalian infection. Although the mammalian-phase RpoS regulon is well described, its counterpart during the transmission blood meal is unknown. Here, we used Bb-specific transcript enrichment by tick-borne disease capture sequencing (TBDCapSeq) to compare the transcriptomes of WT and ΔrpoS Bb in engorged nymphs and following mammalian host-adaptation within dialysis membrane chambers. TBDCapSeq revealed dramatic changes in the contours of the RpoS regulon within ticks and mammals and further confirmed that RpoS-mediated repression is specific to the mammalian-phase of Bb's enzootic cycle. We also provide evidence that RpoS-dependent gene regulation, including repression of tick-phase genes, is required for persistence in mice. Comparative transcriptomics of engineered Bb strains revealed that the Borrelia oxidative stress response regulator (BosR), a noncanonical Fur family member, and the cyclic diguanosine monophosphate (c-di-GMP) effector PlzA reciprocally regulate the function of RNA polymerase complexed with RpoS. BosR is required for RpoS-mediated transcription activation and repression in addition to its well-defined role promoting transcription of rpoS by the RNA polymerase alternative σ factor RpoN. During transmission, ligand-bound PlzA antagonizes RpoS-mediated repression, presumably acting through BosR.
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Affiliation(s)
| | - Rafal Tokarz
- Center for Infection and Immunity and
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, USA
| | - Caroline Golino
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
| | | | - Ashley M. Groshong
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics
| | - Justin D. Radolf
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics
- Department of Molecular Biology and Biophysics
- Department of Genetics and Genome Sciences, and
- Department of Immunology, UConn Health, Farmington, Connecticut, USA
| | - Melissa J. Caimano
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics
- Department of Molecular Biology and Biophysics
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Delgado KN, Montezuma-Rusca JM, Orbe IC, Caimano MJ, La Vake CJ, Luthra A, Hennelly CM, Nindo FN, Meyer JW, Jones LD, Parr JB, Salazar JC, Moody MA, Radolf JD, Hawley KL. Extracellular Loops of the Treponema pallidum FadL Orthologs TP0856 and TP0858 Elicit IgG Antibodies and IgG +-Specific B-Cells in the Rabbit Model of Experimental Syphilis. mBio 2022; 13:e0163922. [PMID: 35862766 PMCID: PMC9426418 DOI: 10.1128/mbio.01639-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 06/14/2022] [Indexed: 12/03/2022] Open
Abstract
The resurgence of syphilis in the new millennium has called attention to the importance of a vaccine for global containment strategies. Studies with immune rabbit serum (IRS) indicate that a syphilis vaccine should elicit antibodies (Abs) that promote opsonophagocytosis of treponemes by activated macrophages. The availability of three-dimensional models for Treponema pallidum's (Tp) repertoire of outer membrane proteins (OMPs) provides an architectural framework for identification of candidate vaccinogens with extracellular loops (ECLs) as the targets for protective Abs. Herein, we used Pyrococcus furiosus thioredoxin (PfTrx) as a scaffold to display Tp OMP ECLs to interrogate sera and peripheral blood mononuclear cells (PBMCs) from immune rabbits for ECL-specific Abs and B cells. We validated this approach using a PfTrx scaffold presenting ECL4 from BamA, a known opsonic target. Using scaffolds displaying ECLs of the FadL orthologs TP0856 and TP0858, we determined that ECL2 and ECL4 of both proteins are strongly antigenic. Comparison of ELISA and immunoblot results suggested that the PfTrx scaffolds present conformational and linear epitopes. We then used the FadL ECL2 and ECL4 PfTrx constructs as "hooks" to confirm the presence of ECL-specific B cells in PBMCs from immune rabbits. Our results pinpoint immunogenic ECLs of two newly discovered OMPs, while advancing the utility of the rabbit model for circumventing bottlenecks in vaccine development associated with large-scale production of folded OMPs. They also lay the groundwork for production of rabbit monoclonal Abs (MAbs) to characterize potentially protective ECL epitopes at the atomic level. IMPORTANCE Recent identification and structural modeling of Treponema pallidum's (Tp) repertoire of outer membrane proteins (OMPs) represent a critical breakthrough in the decades long quest for a syphilis vaccine. However, little is known about the antigenic nature of these β-barrel-forming OMPs and, more specifically, their surface exposed regions, the extracellular loops (ECLs). In this study, using Pyrococcus furiosus thioredoxin (PfTrx) as a scaffold to display Tp OMP ECLs, we interrogated immune rabbit sera and peripheral blood mononuclear cells for the presence of antibodies (Abs) and circulating rare antigen-specific B cells. Our results pinpoint immunogenic ECLs of two newly discovered OMPs, while advancing the utility of the rabbit model for surveying the entire Tp OMPeome for promising OMP vaccinogens. This work represents a major advancement toward characterizing potentially protective OMP ECLs and future vaccine studies. Additionally, this strategy could be applied to OMPs of nonspirochetal bacterial pathogens.
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Affiliation(s)
| | - Jairo M Montezuma-Rusca
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Division of Infectious Diseases, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
| | - Isabel C Orbe
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
| | - Melissa J Caimano
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Carson J La Vake
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
| | - Amit Luthra
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Christopher M Hennelly
- Division of Infectious Diseases, Department of Medicine, and Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Fredrick N Nindo
- Division of Infectious Diseases, Department of Medicine, and Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Jacob W Meyer
- Duke Human Vaccine Institute, Durham, North Carolina, USA
| | | | - Jonathan B Parr
- Division of Infectious Diseases, Department of Medicine, and Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Juan C Salazar
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Division of Infectious Diseases and Immunology, Connecticut Children's, Hartford, Connecticut, USA
- Department of Immunology, UConn Health, Farmington, Connecticut, USA
| | - M Anthony Moody
- Duke Human Vaccine Institute, Durham, North Carolina, USA
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
- Department of Immunology, Duke University Medical Center, Durham, North Carolina, USA
| | - Justin D Radolf
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
- Department of Immunology, UConn Health, Farmington, Connecticut, USA
- Department of Genetics and Genome Sciences, UConn Health, Farmington, Connecticut, USA
| | - Kelly L Hawley
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Division of Infectious Diseases and Immunology, Connecticut Children's, Hartford, Connecticut, USA
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9
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Grassmann AA, Zavala-Alvarado C, Bettin EB, Picardeau M, Benaroudj N, Caimano MJ. The FUR-like regulators PerRA and PerRB integrate a complex regulatory network that promotes mammalian host-adaptation and virulence of Leptospira interrogans. PLoS Pathog 2021; 17:e1009078. [PMID: 34855918 PMCID: PMC8638967 DOI: 10.1371/journal.ppat.1009078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/18/2021] [Indexed: 11/18/2022] Open
Abstract
Leptospira interrogans, the causative agent of most cases of human leptospirosis, must respond to myriad environmental signals during its free-living and pathogenic lifestyles. Previously, we compared L. interrogans cultivated in vitro and in vivo using a dialysis membrane chamber (DMC) peritoneal implant model. From these studies emerged the importance of genes encoding the Peroxide responsive regulators PerRA and PerRB. First described in in Bacillus subtilis, PerRs are widespread in Gram-negative and -positive bacteria, where regulate the expression of gene products involved in detoxification of reactive oxygen species and virulence. Using perRA and perRB single and double mutants, we establish that L. interrogans requires at least one functional PerR for infectivity and renal colonization in a reservoir host. Our finding that the perRA/B double mutant survives at wild-type levels in DMCs is noteworthy as it demonstrates that the loss of virulence is not due to a metabolic lesion (i.e., metal starvation) but instead reflects dysregulation of virulence-related gene products. Comparative RNA-Seq analyses of perRA, perRB and perRA/B mutants cultivated within DMCs identified 106 genes that are dysregulated in the double mutant, including ligA, ligB and lvrA/B sensory histidine kinases. Decreased expression of LigA and LigB in the perRA/B mutant was not due to loss of LvrAB signaling. The majority of genes in the perRA and perRB single and double mutant DMC regulons were differentially expressed only in vivo, highlighting the importance of host signals for regulating gene expression in L. interrogans. Importantly, the PerRA, PerRB and PerRA/B DMC regulons each contain multiple genes related to environmental sensing and/or transcriptional regulation. Collectively, our data suggest that PerRA and PerRB are part of a complex regulatory network that promotes host adaptation by L. interrogans within mammals.
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Affiliation(s)
- André A. Grassmann
- Department of Medicine, University of Connecticut Health, Farmington, Connecticut, United States of America
| | - Crispin Zavala-Alvarado
- Unité de Biologie des Spirochètes, Department of Microbiology, Institut Pasteur, Paris, France
- Université de Paris, Sorbonne Paris Cité, Communauté d’universités et d’établissements (COMUE), Bio Sorbonne Paris Cité (BioSPC), Paris, France
| | - Everton B. Bettin
- Department of Medicine, University of Connecticut Health, Farmington, Connecticut, United States of America
- Programa de Pós-Graduação em Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sol, Brazil
| | - Mathieu Picardeau
- Unité de Biologie des Spirochètes, Department of Microbiology, Institut Pasteur, Paris, France
| | - Nadia Benaroudj
- Unité de Biologie des Spirochètes, Department of Microbiology, Institut Pasteur, Paris, France
| | - Melissa J. Caimano
- Department of Medicine, University of Connecticut Health, Farmington, Connecticut, United States of America
- Department of Pediatrics, University of Connecticut Health, Farmington, Connecticut, United States of America
- Department of Molecular Biology and Biophysics, University of Connecticut Health, Farmington, Connecticut, United States of America
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10
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Craft DL, Korza G, Zhang Y, Frindert J, Jäschke A, Caimano MJ, Setlow P. Analysis of 5'-NAD capping of mRNAs in dormant spores of Bacillus subtilis. FEMS Microbiol Lett 2021; 367:5895323. [PMID: 32821945 DOI: 10.1093/femsle/fnaa143] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 08/18/2020] [Indexed: 12/24/2022] Open
Abstract
Spores of Gram-positive bacteria contain 10s-1000s of different mRNAs. However, Bacillus subtilis spores contain only ∼ 50 mRNAs at > 1 molecule/spore, almost all transcribed only in the developing spore and encoding spore proteins. However, some spore mRNAs could be stabilized to ensure they are intact in dormant spores, perhaps to direct synthesis of proteins essential for spores' conversion to a growing cell in germinated spore outgrowth. Recent work shows that some growing B. subtilis cell mRNAs contain a 5'-NAD cap. Since this cap may stabilize mRNA in vivo, its presence on spore mRNAs would suggest that maintaining some intact spore mRNAs is important, perhaps because they have a translational role in outgrowth. However, significant levels of only a few abundant spore mRNAs had a 5'-NAD cap, and these were not the most stable spore mRNAs and had likely been fragmented. Even higher levels of 5'-NAD-capping were found on a few low abundance spore mRNAs, but these mRNAs were present in only small percentages of spores, and had again been fragmented. The new data are thus consistent with spore mRNAs serving only as a reservoir of ribonucleotides in outgrowth.
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Affiliation(s)
- D Levi Craft
- Department of Molecular Biology and Biophysics, UConn Health, 263 Farmington Avenue, Farmington, CT 06030-3305, USA
| | - George Korza
- Department of Molecular Biology and Biophysics, UConn Health, 263 Farmington Avenue, Farmington, CT 06030-3305, USA
| | - Yaqing Zhang
- Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld, Heidelberg University, 69120, Heidelberg, Germany
| | - Jens Frindert
- Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld, Heidelberg University, 69120, Heidelberg, Germany
| | - Andres Jäschke
- Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld, Heidelberg University, 69120, Heidelberg, Germany
| | - Melissa J Caimano
- Department of Molecular Biology and Biophysics, UConn Health, 263 Farmington Avenue, Farmington, CT 06030-3305, USA.,Department of Medicine, UConn Health, Farmington, CT 06030-3305, USA
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, UConn Health, 263 Farmington Avenue, Farmington, CT 06030-3305, USA
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11
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Hawley KL, Montezuma-Rusca JM, Delgado KN, Singh N, Uversky VN, Caimano MJ, Radolf JD, Luthra A. Structural Modeling of the Treponema pallidum Outer Membrane Protein Repertoire: a Road Map for Deconvolution of Syphilis Pathogenesis and Development of a Syphilis Vaccine. J Bacteriol 2021; 203:e0008221. [PMID: 33972353 PMCID: PMC8407342 DOI: 10.1128/jb.00082-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/27/2021] [Indexed: 01/11/2023] Open
Abstract
Treponema pallidum, an obligate human pathogen, has an outer membrane (OM) whose physical properties, ultrastructure, and composition differ markedly from those of phylogenetically distant Gram-negative bacteria. We developed structural models for the outer membrane protein (OMP) repertoire (OMPeome) of T. pallidum Nichols using solved Gram-negative structures, computational tools, and small-angle X-ray scattering (SAXS) of selected recombinant periplasmic domains. The T. pallidum "OMPeome" harbors two "stand-alone" proteins (BamA and LptD) involved in OM biogenesis and four paralogous families involved in the influx/efflux of small molecules: 8-stranded β-barrels, long-chain-fatty-acid transporters (FadLs), OM factors (OMFs) for efflux pumps, and T. pallidum repeat proteins (Tprs). BamA (TP0326), the central component of a β-barrel assembly machine (BAM)/translocation and assembly module (TAM) hybrid, possesses a highly flexible polypeptide-transport-associated (POTRA) 1-5 arm predicted to interact with TamB (TP0325). TP0515, an LptD ortholog, contains a novel, unstructured C-terminal domain that models inside the β-barrel. T. pallidum has four 8-stranded β-barrels, each containing positively charged extracellular loops that could contribute to pathogenesis. Three of five FadL-like orthologs have a novel α-helical, presumptively periplasmic C-terminal extension. SAXS and structural modeling further supported the bipartite membrane topology and tridomain architecture of full-length members of the Tpr family. T. pallidum's two efflux pumps presumably extrude noxious small molecules via four coexpressed OMFs with variably charged tunnels. For BamA, LptD, and OMFs, we modeled the molecular machines that deliver their substrates into the OM or external milieu. The spirochete's extended families of OM transporters collectively confer a broad capacity for nutrient uptake. The models also furnish a structural road map for vaccine development. IMPORTANCE The unusual outer membrane (OM) of T. pallidum, the syphilis spirochete, is the ultrastructural basis for its well-recognized capacity for invasiveness, immune evasion, and persistence. In recent years, we have made considerable progress in identifying T. pallidum's repertoire of OMPs. Here, we developed three-dimensional (3D) models for the T. pallidum Nichols OMPeome using structural modeling, bioinformatics, and solution scattering. The OM contains three families of OMP transporters, an OMP family involved in the extrusion of noxious molecules, and two "stand-alone" proteins involved in OM biogenesis. This work represents a major advance toward elucidating host-pathogen interactions during syphilis; understanding how T. pallidum, an extreme auxotroph, obtains a wide array of biomolecules from its obligate human host; and developing a vaccine with global efficacy.
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Affiliation(s)
- Kelly L. Hawley
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Division of Infectious Diseases and Immunology, Connecticut Children’s, Hartford, Connecticut, USA
| | - Jairo M. Montezuma-Rusca
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Division of Infectious Diseases, UConn Health, Farmington, Connecticut, USA
| | | | - Navreeta Singh
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
| | - Vladimir N. Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Melissa J. Caimano
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Justin D. Radolf
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
- Department of Genetics and Genome Sciences, UConn Health, Farmington, Connecticut, USA
- Department of Immunology, UConn Health, Farmington, Connecticut, USA
| | - Amit Luthra
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, 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] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 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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Abstract
In order to sustain its zoonotic lifecycle, leptospires must adapt to growth within the host milieu. Signals encountered within the mammal also trigger regulatory programs required by Leptospira for the expression of virulence-related gene products. The complex transcriptional, antigenic, and physiological changes leptospires undergo within the mammal are collectively referred to as "host adaptation." In this chapter, we describe the procedures for the generation of host-adapted Leptospira spp. by cultivation within dialysis membrane chambers (DMCs) implanted in rat peritoneal cavities. In this model, Leptospira spp. diluted in EMJH medium are sequestered within sterile dialysis membrane tubing closed at both ends. The chamber then is surgically implanted within the peritoneal cavity of a rat and incubated for 7-10 days. During this period, leptospires are exposed to many, if not all, of the physiological and nutritional cues required for host adaptation while at the same time protected from clearance by host innate and adaptive immune defenses.
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Affiliation(s)
| | - Melissa J Caimano
- Departments of Medicine, Pediatrics, and Molecular Biology and Biophysics, University of Connecticut Health, Farmington, CT, USA.
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14
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Samuels DS, Lybecker MC, Yang XF, Ouyang Z, Bourret TJ, Boyle WK, Stevenson B, Drecktrah D, Caimano MJ. Gene Regulation and Transcriptomics. Curr Issues Mol Biol 2020; 42:223-266. [PMID: 33300497 DOI: 10.21775/cimb.042.223] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Borrelia (Borreliella) burgdorferi, along with closely related species, is the etiologic agent of Lyme disease. The spirochete subsists in an enzootic cycle that encompasses acquisition from a vertebrate host to a tick vector and transmission from a tick vector to a vertebrate host. To adapt to its environment and persist in each phase of its enzootic cycle, B. burgdorferi wields three systems to regulate the expression of genes: the RpoN-RpoS alternative sigma factor cascade, the Hk1/Rrp1 two-component system and its product c-di-GMP, and the stringent response mediated by RelBbu and DksA. These regulatory systems respond to enzootic phase-specific signals and are controlled or fine- tuned by transcription factors, including BosR and BadR, as well as small RNAs, including DsrABb and Bb6S RNA. In addition, several other DNA-binding and RNA-binding proteins have been identified, although their functions have not all been defined. Global changes in gene expression revealed by high-throughput transcriptomic studies have elucidated various regulons, albeit technical obstacles have mostly limited this experimental approach to cultivated spirochetes. Regardless, we know that the spirochete, which carries a relatively small genome, regulates the expression of a considerable number of genes required for the transitions between the tick vector and the vertebrate host as well as the adaptation to each.
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Affiliation(s)
- D Scott Samuels
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Meghan C Lybecker
- Department of Biology, University of Colorado, Colorado Springs, CO 80918, USA
| | - X Frank Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Zhiming Ouyang
- Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Travis J Bourret
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE, 68105 USA
| | - William K Boyle
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE, 68105 USA
| | - Brian Stevenson
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky School of Medicine, Lexington, KY 40536, USA
| | - Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Melissa J Caimano
- Departments of Medicine, Pediatrics, and Molecular Biology and Biophysics, UConn Health, Farmington, CT, USA
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15
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Luthra A, Montezuma-Rusca JM, La Vake CJ, LeDoyt M, Delgado KN, Davenport TC, Fiel-Gan M, Caimano MJ, Radolf JD, Hawley KL. Evidence that immunization with TP0751, a bipartite Treponema pallidum lipoprotein with an intrinsically disordered region and lipocalin fold, fails to protect in the rabbit model of experimental syphilis. PLoS Pathog 2020; 16:e1008871. [PMID: 32936831 PMCID: PMC7521688 DOI: 10.1371/journal.ppat.1008871] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 09/28/2020] [Accepted: 08/10/2020] [Indexed: 12/18/2022] Open
Abstract
Deconvolution of syphilis pathogenesis and selection of candidate syphilis vaccinogens requires detailed knowledge of the molecular architecture of the Treponema pallidum outer membrane (OM). The T. pallidum OM contains a low density of integral OM proteins, while the spirochete's many lipoprotein immunogens are periplasmic. TP0751, a lipoprotein with a lipocalin fold, is reportedly a surface-exposed protease/adhesin and protective antigen. The rapid expansion of calycin/lipocalin structures in the RCSB PDB database prompted a comprehensive reassessment of TP0751. Small angle X-ray scattering analysis of full-length protein revealed a bipartite topology consisting of an N-terminal, intrinsically disordered region (IDR) and the previously characterized C-terminal lipocalin domain. A DALI server query using the lipocalin domain yielded 97 hits, 52 belonging to the calycin superfamily, including 15 bacterial lipocalins, but no Gram-negative surface proteins. Surprisingly, Tpp17 (TP0435) was identified as a structural ortholog of TP0751. In silico docking predicted that TP0751 can bind diverse ligands along the rim of its eight-stranded β-barrel; high affinity binding of one predicted ligand, heme, to the lipocalin domain was demonstrated. qRT-PCR and immunoblotting revealed very low expression of TP0751 compared to other T. pallidum lipoproteins. Immunoblot analysis of immune rabbit serum failed to detect TP0751 antibodies, while only one of five patients with secondary syphilis mounted a discernible TP0751-specific antibody response. In opsonophagocytosis assays, neither TP0751 nor Tpp17 antibodies promoted uptake of T. pallidum by rabbit peritoneal macrophages. Rabbits immunized with intact, full-length TP0751 showed no protection against local or disseminated infection following intradermal challenge with T. pallidum. Our data argue that, like other lipoprotein lipocalins in dual-membrane bacteria, TP0751 is periplasmic and binds small molecules, and we propose that its IDR facilitates ligand binding by and offloading from the lipocalin domain. The inability of TP0751 to elicit opsonic or protective antibodies is consistent with a subsurface location.
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Affiliation(s)
- Amit Luthra
- Department of Medicine, UConn Health, Farmington, United States of America
| | - Jairo M. Montezuma-Rusca
- Department of Medicine, UConn Health, Farmington, United States of America
- Division of Infectious Diseases, UConn Health, Farmington, United States of America
- Department of Pediatrics, UConn Health, Farmington, United States of America
| | - Carson J. La Vake
- Department of Pediatrics, UConn Health, Farmington, United States of America
| | - Morgan LeDoyt
- Department of Medicine, UConn Health, Farmington, United States of America
| | | | | | - Mary Fiel-Gan
- Department of Pathology, Hartford Hospital, Hartford, United States of America
| | - Melissa J. Caimano
- Department of Medicine, UConn Health, Farmington, United States of America
- Department of Pediatrics, UConn Health, Farmington, United States of America
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, United States of America
| | - Justin D. Radolf
- Department of Medicine, UConn Health, Farmington, United States of America
- Department of Pediatrics, UConn Health, Farmington, United States of America
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, United States of America
- Department of Genetics and Genome Sciences, UConn Health, Farmington, United States of America
- Department of Immunology, UConn Health, Farmington, United States of America
| | - Kelly L. Hawley
- Department of Pediatrics, UConn Health, Farmington, United States of America
- Division of Infectious Diseases and Immunology, Connecticut Children’s, Hartford, United States of America
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16
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Chen W, Šmajs D, Hu Y, Ke W, Pospíšilová P, Hawley KL, Caimano MJ, Radolf JD, Sena A, Tucker JD, Yang B, Juliano JJ, Zheng H, Parr JB. Analysis of Treponema pallidum Strains From China Using Improved Methods for Whole-Genome Sequencing From Primary Syphilis Chancres. J Infect Dis 2020; 223:848-853. [PMID: 32710788 DOI: 10.1093/infdis/jiaa449] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/20/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Whole-genome sequencing (WGS) of Treponema pallidum subspecies pallidum (TPA) has been constrained by the lack of in vitro cultivation methods for isolating spirochetes from patient samples. METHODS We built upon recently developed enrichment methods to sequence TPA directly from primary syphilis chancre swabs collected in Guangzhou, China. RESULTS By combining parallel, pooled whole-genome amplification with hybrid selection, we generated high-quality genomes from 4 of 8 chancre-swab samples and 2 of 2 rabbit-passaged isolates, all subjected to challenging storage conditions. CONCLUSIONS This approach enabled the first WGS of Chinese samples without rabbit passage and provided insights into TPA genetic diversity in China.
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Affiliation(s)
- Wentao Chen
- Dermatology Hospital, Southern Medical University, Guangzhou, China
| | - David Šmajs
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Yongfei Hu
- Dermatology Hospital, Southern Medical University, Guangzhou, China
| | - Wujian Ke
- Dermatology Hospital, Southern Medical University, Guangzhou, China
| | - Petra Pospíšilová
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Kelly L Hawley
- Division of Infectious Diseases and Department of Pediatrics, Connecticut Children's Medical Center, Hartford, Connecticut, USA
| | - Melissa J Caimano
- Departments of Medicine, Pediatrics, and Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Justin D Radolf
- Departments of Medicine, Pediatrics, and Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA.,Departments of Genetics and Genome Sciences, and Immunology, UConn Health, Farmington, Connecticut, USA
| | - Arlene Sena
- Division of Infectious Diseases, Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Joseph D Tucker
- Division of Infectious Diseases, Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA.,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Bin Yang
- Dermatology Hospital, Southern Medical University, Guangzhou, China
| | - Jonathan J Juliano
- Division of Infectious Diseases, Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA.,Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA.,Curriculum in Genetics and Molecular Biology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Heping Zheng
- Dermatology Hospital, Southern Medical University, Guangzhou, China
| | - Jonathan B Parr
- Division of Infectious Diseases, Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA.,Curriculum in Genetics and Molecular Biology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
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17
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Souza JGS, Bertolini M, Thompson A, Mansfield JM, Grassmann AA, Maas K, Caimano MJ, Barao VAR, Vickerman MM, Dongari-Bagtzoglou A. Role of glucosyltransferase R in biofilm interactions between Streptococcus oralis and Candida albicans. ISME J 2020; 14:1207-1222. [PMID: 32042100 PMCID: PMC7174356 DOI: 10.1038/s41396-020-0608-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 01/08/2020] [Accepted: 01/30/2020] [Indexed: 02/08/2023]
Abstract
Streptococcal glucosyltransferases (Gtf) synthesize α-glucan exopolymers which contribute to biofilm matrix. Streptococcus oralis interacts with the opportunistic pathogen Candida albicans to form hypervirulent biofilms. S. oralis 34 has a single gtf gene (gtfR). However, the role of gtfR in single and mixed species biofilms with C. albicans has never been examined. A gtfR deletion mutant, purified GtfR, and recombinant GtfR glucan-binding domain were tested in single and mixed biofilms on different substrata in vitro. A mouse oral infection model was also used. We found that in single species biofilms growing with sucrose on abiotic surfaces S. oralis gtfR increased biofilm matrix, but not bacterial biomass. In biofilms with C. albicans, S. oralis encoding gtfR showed increased bacterial biomass on all surfaces. C. albicans had a positive effect on α-glucan synthesis, and α-glucans increased C. albicans accretion on abiotic surfaces. In single and mixed infection of mice receiving sucrose S. oralis gtfR enhanced mucosal burdens. However, sucrose had a negative impact on C. albicans burdens and reduced S. oralis burdens in co-infected mice. Our data provide new insights on the GtfR-mediated interactions between the two organisms and the influence of biofilm substratum and the mucosal environment on these interactions.
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Affiliation(s)
- João Gabriel Silva Souza
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT, USA
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, São Paulo, Brazil
| | - Martinna Bertolini
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT, USA
| | - Angela Thompson
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT, USA
| | - Jillian M Mansfield
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY, USA
| | - André Alex Grassmann
- Departments of Medicine, Pediatrics and Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| | - Kendra Maas
- Microbial Analysis, Resources, and Services Core, University of Connecticut, Storrs, CT, USA
| | - Melissa J Caimano
- Departments of Medicine, Pediatrics and Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| | - Valentim Adelino Ricardo Barao
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, São Paulo, Brazil
| | - M Margaret Vickerman
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY, USA.
| | - Anna Dongari-Bagtzoglou
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT, USA.
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18
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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: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [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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19
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Lindberg TP, Caimano MJ, Hagadorn JI, Bennett EM, Maas K, Brownell EA, Matson AP. Preterm infant gut microbial patterns related to the development of necrotizing enterocolitis. J Matern Fetal Neonatal Med 2018; 33:349-358. [PMID: 29909714 DOI: 10.1080/14767058.2018.1490719] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Objectives: To define gut microbial patterns in preterm infants with and without necrotizing enterocolitis (NEC) and to characterize clinical factors related to the composition of the preterm intestinal microbiome.Methods: Fecal samples were collected at one-week intervals from infants with gestational ages <30 weeks at a single level IV neonatal intensive care unit. Using 16S rRNA gene sequencing, the composition and diversity of microbiota were determined in samples collected from five NEC infants and five matched controls. Hierarchical linear regression was used to identify clinical factors related to microbial diversity and specific bacterial signatures.Results: Low levels of diversity were demonstrated in samples obtained from all preterm infants and antibiotic exposure further decreased diversity among both NEC cases and controls. Fecal microbial composition differed between NEC cases and controls, with a greater abundance of Proteobacteria and bacteria belonging to the class Gammaproteobacteria among NEC infants. Control infants demonstrated a greater abundance of bacteria belonging to the phylum Firmicutes.Conclusion: These findings indicate that an association exists between intestinal Proteobacteria and NEC, and strengthens the notion that an overly exuberant response to Gram-negative products, particularly lipopolysaccharide, in the preterm intestine is involved in NEC pathogenesis. Cumulative exposure to antibiotics corresponded to a reduction in microbial diversity in both NEC cases and controls.
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Affiliation(s)
- Tristan P Lindberg
- Division of Neonatology, Connecticut Children's Medical Center, Hartford, CT, USA.,University of Connecticut School of Medicine, Farmington, CT, USA
| | | | - James I Hagadorn
- Division of Neonatology, Connecticut Children's Medical Center, Hartford, CT, USA.,University of Connecticut School of Medicine, Farmington, CT, USA
| | - Erin M Bennett
- Division of Research, Connecticut Children's Medical Center, Hartford, CT, USA
| | | | - Elizabeth A Brownell
- Division of Neonatology, Connecticut Children's Medical Center, Hartford, CT, USA.,University of Connecticut School of Medicine, Farmington, CT, USA.,Division of Research, Connecticut Children's Medical Center, Hartford, CT, USA
| | - Adam P Matson
- Division of Neonatology, Connecticut Children's Medical Center, Hartford, CT, USA.,University of Connecticut School of Medicine, Farmington, CT, USA
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20
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Kumar S, Caimano MJ, Anand A, Dey A, Hawley KL, LeDoyt ME, La Vake CJ, Cruz AR, Ramirez LG, Paštěková L, Bezsonova I, Šmajs D, Salazar JC, Radolf JD. Sequence Variation of Rare Outer Membrane Protein β-Barrel Domains in Clinical Strains Provides Insights into the Evolution of Treponema pallidum subsp. pallidum, the Syphilis Spirochete. mBio 2018; 9:e01006-18. [PMID: 29895642 PMCID: PMC6016234 DOI: 10.1128/mbio.01006-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 05/10/2018] [Indexed: 02/07/2023] Open
Abstract
In recent years, considerable progress has been made in topologically and functionally characterizing integral outer membrane proteins (OMPs) of Treponema pallidum subspecies pallidum, the syphilis spirochete, and identifying its surface-exposed β-barrel domains. Extracellular loops in OMPs of Gram-negative bacteria are known to be highly variable. We examined the sequence diversity of β-barrel-encoding regions of tprC, tprD, and bamA in 31 specimens from Cali, Colombia; San Francisco, California; and the Czech Republic and compared them to allelic variants in the 41 reference genomes in the NCBI database. To establish a phylogenetic framework, we used T. pallidum 0548 (tp0548) genotyping and tp0558 sequences to assign strains to the Nichols or SS14 clades. We found that (i) β-barrels in clinical strains could be grouped according to allelic variants in T. pallidum subsp. pallidum reference genomes; (ii) for all three OMP loci, clinical strains within the Nichols or SS14 clades often harbored β-barrel variants that differed from the Nichols and SS14 reference strains; and (iii) OMP variable regions often reside in predicted extracellular loops containing B-cell epitopes. On the basis of structural models, nonconservative amino acid substitutions in predicted transmembrane β-strands of T. pallidum repeat C (TprC) and TprD2 could give rise to functional differences in their porin channels. OMP profiles of some clinical strains were mosaics of different reference strains and did not correlate with results from enhanced molecular typing. Our observations suggest that human host selection pressures drive T. pallidum subsp. pallidum OMP diversity and that genetic exchange contributes to the evolutionary biology of T. pallidum subsp. pallidum They also set the stage for topology-based analysis of antibody responses to OMPs and help frame strategies for syphilis vaccine development.IMPORTANCE Despite recent progress characterizing outer membrane proteins (OMPs) of Treponema pallidum, little is known about how their surface-exposed, β-barrel-forming domains vary among strains circulating within high-risk populations. In this study, sequences for the β-barrel-encoding regions of three OMP loci, tprC, tprD, and bamA, in T. pallidum subsp. pallidum isolates from a large number of patient specimens from geographically disparate sites were examined. Structural models predict that sequence variation within β-barrel domains occurs predominantly within predicted extracellular loops. Amino acid substitutions in predicted transmembrane strands that could potentially affect porin channel function were also noted. Our findings suggest that selection pressures exerted within human populations drive T. pallidum subsp. pallidum OMP diversity and that recombination at OMP loci contributes to the evolutionary biology of syphilis spirochetes. These results also set the stage for topology-based analysis of antibody responses that promote clearance of T. pallidum subsp. pallidum and frame strategies for vaccine development based upon conserved OMP extracellular loops.
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Affiliation(s)
- Sanjiv Kumar
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
| | - Melissa J Caimano
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Arvind Anand
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
| | - Abhishek Dey
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
| | - Kelly L Hawley
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Division of Pediatric Infectious Diseases, Connecticut Children's Medical Center, Hartford, Connecticut, USA
| | - Morgan E LeDoyt
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
| | - Carson J La Vake
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
| | - Adriana R Cruz
- Centro Internacional de Entrenamiento e Investigaciones Medicas (CIDEIM), Cali, Colombia
| | - Lady G Ramirez
- Centro Internacional de Entrenamiento e Investigaciones Medicas (CIDEIM), Cali, Colombia
| | - Lenka Paštěková
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Irina Bezsonova
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - David Šmajs
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Juan C Salazar
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Division of Pediatric Infectious Diseases, Connecticut Children's Medical Center, Hartford, Connecticut, USA
- Centro Internacional de Entrenamiento e Investigaciones Medicas (CIDEIM), Cali, Colombia
- Department of Immunology, UConn Health, Farmington, Connecticut, USA
| | - Justin D Radolf
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
- Department of Immunology, UConn Health, Farmington, Connecticut, USA
- Department of Genetic and Genome Sciences, UConn Health, Farmington, Connecticut, USA
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21
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Abstract
The transmission, survival, and virulence of Borrelia burgdorferi depend upon the spirochete's ability to modulate its transcriptome as it cycles between its arthropod vector and reservoir host. This complex adaptive process is collectively referred to as "host-adaptation." The paucibacillary nature of borrelial infections precludes the detailed analysis of host adaptation within infected mammalian tissues. To circumvent this limitation, we (J Clin Invest 101:2240-2250, 1998) developed a model system whereby spirochetes are cultivated within dialysis membrane chambers (DMCs) surgically implanted within the peritoneal cavity of a rat. Spirochetes within DMCs are exposed to many, if not all, of the environmental signals and physiological cues required for mammalian host adaptation but are protected from clearance by the host's immune system.
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Affiliation(s)
- Melissa J Caimano
- Department of Medicine, UConn Health, 263 Farmington Ave., Farmington, CT, 06030-3715, USA.
- Department of Pediatrics, UConn Health, 263 Farmington Ave., Farmington, CT, 06030-3715, USA.
- Department of Molecular Biology and Biophysics, UConn Health, 263 Farmington Ave., Farmington, CT, 06030-3715, USA.
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22
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Hawley KL, Cruz AR, Benjamin SJ, La Vake CJ, Cervantes JL, LeDoyt M, Ramirez LG, Mandich D, Fiel-Gan M, Caimano MJ, Radolf JD, Salazar JC. IFNγ Enhances CD64-Potentiated Phagocytosis of Treponema pallidum Opsonized with Human Syphilitic Serum by Human Macrophages. Front Immunol 2017; 8:1227. [PMID: 29051759 PMCID: PMC5633599 DOI: 10.3389/fimmu.2017.01227] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 09/15/2017] [Indexed: 12/23/2022] Open
Abstract
Syphilis is a multi-stage, sexually transmitted disease caused by the spirochete Treponema pallidum (Tp). Considered broadly, syphilis can be conceptualized as a dualistic process in which spirochete-driven inflammation, the cause of clinical manifestations, coexists to varying extents with bacterial persistence. Inflammation is elicited in the tissues, along with the persistence of spirochetes to keep driving a robust immune response while evading host defenses; this duality is best exemplified during the florid, disseminated stage called secondary syphilis (SS). SS lesions typically contain copious amounts of spirochetes along with a mixed cellular infiltrate consisting of CD4+ T cells, CD8+ T cells, NK cells, plasma cells, and macrophages. In the rabbit model, Tp are cleared by macrophages via antibody-mediated opsonophagocytosis. Previously, we demonstrated that human syphilitic serum (HSS) promotes efficient uptake of Tp by human monocytes and that opsonophagocytosis of Tp markedly enhances cytokine production. Herein, we used monocyte-derived macrophages to study Tp–macrophage interactions ex vivo. In the absence of HSS, monocyte-derived macrophages internalized low numbers of Tp and secreted little cytokine (e.g., TNF). By contrast, these same macrophages internalized large numbers of unopsonized Borrelia burgdorferi and secreted robust levels of cytokines. Maturation of macrophages with M-CSF and IFNγ resulted in a macrophage phenotype with increased expression of HLA-DR, CD14, inducible nitric oxide synthase, TLR2, TLR8, and the Fcγ receptors (FcγR) CD64 and CD16, even in the absence of LPS. Importantly, IFNγ-polarized macrophages resulted in a statistically significant increase in opsonophagocytosis of Tp accompanied by enhanced production of cytokines, macrophage activation markers (CD40, CD80), TLRs (TLR2, TLR7, TLR8), chemokines (CCL19, CXCL10, CXCL11), and TH1-promoting cytokines (IL-12, IL-15). Finally, the blockade of FcγRs, primarily CD64, significantly diminished spirochetal uptake and proinflammatory cytokine secretion by IFNγ-stimulated macrophages. Our ex vivo studies demonstrate the importance of CD64-potentiated uptake of opsonized Tp and suggest that IFNγ-activated macrophages have an important role in the context of early syphilis. Our study results also provide an ex vivo surrogate system for use in future syphilis vaccine studies.
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Affiliation(s)
- Kelly L Hawley
- Department of Pediatrics, UConn Health, Farmington, CT, United States.,Division of Infectious Diseases, Connecticut Children's Medical Center, Hartford, CT, United States
| | - Adriana R Cruz
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
| | - Sarah J Benjamin
- Department of Pediatrics, UConn Health, Farmington, CT, United States.,Division of Infectious Diseases, Connecticut Children's Medical Center, Hartford, CT, United States.,Department of Immunology, UConn Health, Farmington, CT, United States
| | - Carson J La Vake
- Department of Pediatrics, UConn Health, Farmington, CT, United States
| | - Jorge L Cervantes
- Department of Pediatrics, UConn Health, Farmington, CT, United States.,Division of Infectious Diseases, Connecticut Children's Medical Center, Hartford, CT, United States
| | - Morgan LeDoyt
- Department of Medicine, UConn Health, Farmington, CT, United States
| | - Lady G Ramirez
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
| | - Daniza Mandich
- Department of Pathology, Hartford Hospital, Hartford, CT, United States
| | - Mary Fiel-Gan
- Department of Pathology, Hartford Hospital, Hartford, CT, United States
| | | | - Justin D Radolf
- Department of Pediatrics, UConn Health, Farmington, CT, United States.,Division of Infectious Diseases, Connecticut Children's Medical Center, Hartford, CT, United States.,Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia.,Department of Immunology, UConn Health, Farmington, CT, United States.,Department of Medicine, UConn Health, Farmington, CT, United States.,Department of Genetics and Developmental Biology, UConn Health, Farmington, CT, United States
| | - Juan C Salazar
- Department of Pediatrics, UConn Health, Farmington, CT, United States.,Division of Infectious Diseases, Connecticut Children's Medical Center, Hartford, CT, United States.,Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia.,Department of Immunology, UConn Health, Farmington, CT, United States
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23
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Nally JE, Grassmann AA, Planchon S, Sergeant K, Renaut J, Seshu J, McBride AJ, Caimano MJ. Pathogenic Leptospires Modulate Protein Expression and Post-translational Modifications in Response to Mammalian Host Signals. Front Cell Infect Microbiol 2017; 7:362. [PMID: 28848720 PMCID: PMC5553009 DOI: 10.3389/fcimb.2017.00362] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 07/26/2017] [Indexed: 12/24/2022] Open
Abstract
Pathogenic species of Leptospira cause leptospirosis, a bacterial zoonotic disease with a global distribution affecting over one million people annually. Reservoir hosts of leptospirosis, including rodents, dogs, and cattle, exhibit little to no signs of disease but shed large numbers of organisms in their urine. Transmission occurs when mucosal surfaces or abraded skin come into contact with infected urine or urine-contaminated water or soil. Whilst little is known about how Leptospira adapt to and persist within a reservoir host, in vitro studies suggest that leptospires alter their transcriptomic and proteomic profiles in response to environmental signals encountered during mammalian infection. We applied the dialysis membrane chamber (DMC) peritoneal implant model to compare the whole cell proteome of in vivo derived leptospires with that of leptospires cultivated in vitro at 30°C and 37°C by 2-dimensional difference in-gel electrophoresis (2-D DIGE). Of 1,735 protein spots aligned across 9 2-D DIGE gels, 202 protein spots were differentially expressed (p < 0.05, fold change >1.25 or < −1.25) across all three conditions. Differentially expressed proteins were excised for identification by mass spectrometry. Data are available via ProteomeXchange with identifier PXD006995. The greatest differences were detected when DMC-cultivated leptospires were compared with IV30- or IV37-cultivated leptospires, including the increased expression of multiple isoforms of Loa22, a known virulence factor. Unexpectedly, 20 protein isoforms of LipL32 and 7 isoforms of LipL41 were uniformly identified by DIGE as differentially expressed, suggesting that unique post-translational modifications (PTMs) are operative in response to mammalian host conditions. To test this hypothesis, a rat model of persistent renal colonization was used to isolate leptospires directly from the urine of experimentally infected rats. Comparison of urinary derived leptospires to IV30 leptospires by 2-D immunoblotting confirmed that modification of proteins with trimethyllysine and acetyllysine occurs to a different degree in response to mammalian host signals encountered during persistent renal colonization. These results provide novel insights into differential protein and PTMs present in response to mammalian host signals which can be used to further define the unique equilibrium that exists between pathogenic leptospires and their reservoir host of infection.
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Affiliation(s)
- Jarlath E Nally
- Infectious Bacterial Diseases Research, National Animal Disease Center, United States Department of Agriculture, Agricultural Research ServiceAmes, IA, United States
| | - Andre A Grassmann
- Biotechnology Unit, Technological Development Center, Federal University of PelotasPelotas, Brazil.,Departments of Medicine, Pediatrics, and Molecular Biology and Biophysics, University of Connecticut Health CenterFarmington, CT, United States
| | - Sébastien Planchon
- Environmental Research and Innovation Department, Luxembourg Institute of Science and TechnologyBelvaux, Luxembourg
| | - Kjell Sergeant
- Environmental Research and Innovation Department, Luxembourg Institute of Science and TechnologyBelvaux, Luxembourg
| | - Jenny Renaut
- Environmental Research and Innovation Department, Luxembourg Institute of Science and TechnologyBelvaux, Luxembourg
| | - Janakiram Seshu
- Department of Biology, University of Texas San AntoniaSan Antonia, TX, United States
| | - Alan J McBride
- Biotechnology Unit, Technological Development Center, Federal University of PelotasPelotas, Brazil.,Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Ministry of HealthSalvador, Brazil
| | - Melissa J Caimano
- Departments of Medicine, Pediatrics, and Molecular Biology and Biophysics, University of Connecticut Health CenterFarmington, CT, United States
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24
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Abstract
Human milk-associated microbes are among the first to colonize the infant gut and may help to shape both short- and long-term infant health outcomes. We performed a systematic review to characterize the microbiota of human milk. Relevant primary studies were identified through a comprehensive search of PubMed (January 1, 1964, to June 31, 2015). Included studies were conducted among healthy mothers, were written in English, identified bacteria in human milk, used culture-independent methods, and reported primary results at the genus level. Twelve studies satisfied inclusion criteria. All varied in geographic location and human milk collection/storage/analytic methods. Streptococcus was identified in human milk samples in 11 studies (91.6%) and Staphylococcus in 10 (83.3%); both were predominant genera in 6 (50%). Eight of the 12 studies used conventional ribosomal RNA (rRNA) polymerase chain reaction (PCR), of which 7 (87.5%) identified Streptococcus and 6 (80%) identified Staphylococcus as present. Of these 8 studies, 2 (25%) identified Streptococcus and Staphylococcus as predominant genera. Four of the 12 studies used next-generation sequencing (NGS), all of which identified Streptococcus and Staphylococcus as present and predominant genera. Relative to conventional rRNA PCR, NGS is a more sensitive method to identify/quantify bacterial genera in human milk, suggesting the predominance of Streptococcus and Staphylococcus may be underestimated in studies using older methods. These genera, Streptococcus and Staphylococcus, may be universally predominant in human milk, regardless of differences in geographic location or analytic methods. Primary studies designed to evaluate the effect of these 2 genera on short- and long-term infant outcomes are warranted.
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Affiliation(s)
- John L Fitzstevens
- 1 Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, USA
| | - Kelsey C Smith
- 2 Connecticut Human Milk Research Center, Connecticut Children's Medical Center, Hartford, Connecticut, USA.,3 Division of Neonatology, Connecticut Children's Medical Center, Hartford, Connecticut, USA
| | - James I Hagadorn
- 2 Connecticut Human Milk Research Center, Connecticut Children's Medical Center, Hartford, Connecticut, USA.,3 Division of Neonatology, Connecticut Children's Medical Center, Hartford, Connecticut, USA.,4 Department of Pediatrics, University of Connecticut School of Medicine, Farmington, Connecticut, USA
| | - Melissa J Caimano
- 5 Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA.,6 Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Adam P Matson
- 3 Division of Neonatology, Connecticut Children's Medical Center, Hartford, Connecticut, USA.,4 Department of Pediatrics, University of Connecticut School of Medicine, Farmington, Connecticut, USA.,7 Department of Immunology, University of Connecticut School of Medicine, Farmington, Connecticut, USA
| | - Elizabeth A Brownell
- 2 Connecticut Human Milk Research Center, Connecticut Children's Medical Center, Hartford, Connecticut, USA.,3 Division of Neonatology, Connecticut Children's Medical Center, Hartford, Connecticut, USA.,4 Department of Pediatrics, University of Connecticut School of Medicine, Farmington, Connecticut, USA
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25
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Caimano MJ, Drecktrah D, Kung F, Samuels DS. Interaction of the Lyme disease spirochete with its tick vector. Cell Microbiol 2016; 18:919-27. [PMID: 27147446 DOI: 10.1111/cmi.12609] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 04/27/2016] [Accepted: 05/03/2016] [Indexed: 01/01/2023]
Abstract
Borrelia burgdorferi, the causative agent of Lyme disease (along with closely related genospecies), is in the deeply branching spirochete phylum. The bacterium is maintained in nature in an enzootic cycle that involves transmission from a tick vector to a vertebrate host and acquisition from a vertebrate host to a tick vector. During its arthropod sojourn, B. burgdorferi faces a variety of stresses, including nutrient deprivation. Here, we review some of the spirochetal factors that promote persistence, maintenance and dissemination of B. burgdorferi in the tick, and then focus on the utilization of available carbohydrates as well as the exquisite regulatory systems invoked to adapt to the austere environment between blood meals and to signal species transitions as the bacteria traverse their enzootic cycle. The spirochetes shift their source of carbon and energy from glucose in the vertebrate to glycerol in the tick. Regulation of survival under limiting nutrients requires the classic stringent response in which RelBbu controls the levels of the alarmones guanosine tetraphosphate and guanosine pentaphosphate (collectively termed (p)ppGpp), while regulation at the tick-vertebrate interface as well as regulation of protective responses to the blood meal require the two-component system Hk1/Rrp1 to activate production of the second messenger cyclic-dimeric-GMP (c-di-GMP).
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Affiliation(s)
- Melissa J Caimano
- Departments of Medicine, Pediatrics, and Molecular Biology and Biophysics, UConn Health, Farmington, CT, USA
| | - Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Faith Kung
- Department of Veterinary Medicine, University of Maryland-College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, USA
| | - D Scott Samuels
- Division of Biological Sciences, University of Montana, Missoula, MT, USA.,Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT, USA
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Gulia-Nuss M, Nuss AB, Meyer JM, Sonenshine DE, Roe RM, Waterhouse RM, Sattelle DB, de la Fuente J, Ribeiro JM, Megy K, Thimmapuram J, Miller JR, Walenz BP, Koren S, Hostetler JB, Thiagarajan M, Joardar VS, Hannick LI, Bidwell S, Hammond MP, Young S, Zeng Q, Abrudan JL, Almeida FC, Ayllón N, Bhide K, Bissinger BW, Bonzon-Kulichenko E, Buckingham SD, Caffrey DR, Caimano MJ, Croset V, Driscoll T, Gilbert D, Gillespie JJ, Giraldo-Calderón GI, Grabowski JM, Jiang D, Khalil SMS, Kim D, Kocan KM, Koči J, Kuhn RJ, Kurtti TJ, Lees K, Lang EG, Kennedy RC, Kwon H, Perera R, Qi Y, Radolf JD, Sakamoto JM, Sánchez-Gracia A, Severo MS, Silverman N, Šimo L, Tojo M, Tornador C, Van Zee JP, Vázquez J, Vieira FG, Villar M, Wespiser AR, Yang Y, Zhu J, Arensburger P, Pietrantonio PV, Barker SC, Shao R, Zdobnov EM, Hauser F, Grimmelikhuijzen CJP, Park Y, Rozas J, Benton R, Pedra JHF, Nelson DR, Unger MF, Tubio JMC, Tu Z, Robertson HM, Shumway M, Sutton G, Wortman JR, Lawson D, Wikel SK, Nene VM, Fraser CM, Collins FH, Birren B, Nelson KE, Caler E, Hill CA. Genomic insights into the Ixodes scapularis tick vector of Lyme disease. Nat Commun 2016; 7:10507. [PMID: 26856261 PMCID: PMC4748124 DOI: 10.1038/ncomms10507] [Citation(s) in RCA: 328] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 12/12/2015] [Indexed: 01/06/2023] Open
Abstract
Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retro-transposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing ∼57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick-host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host 'questing', prolonged feeding, cuticle synthesis, blood meal concentration, novel methods of haemoglobin digestion, haem detoxification, vitellogenesis and prolonged off-host survival. We identify proteins associated with the agent of human granulocytic anaplasmosis, an emerging disease, and the encephalitis-causing Langat virus, and a population structure correlated to life-history traits and transmission of the Lyme disease agent.
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Affiliation(s)
- Monika Gulia-Nuss
- Department of Entomology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Andrew B. Nuss
- Department of Entomology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Jason M. Meyer
- Department of Entomology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Daniel E. Sonenshine
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginina 23529, USA
| | - R. Michael Roe
- Department of Entomology, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Robert M. Waterhouse
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva 1211, Switzerland
- Swiss Institute of Bioinformatics, Geneva 1211, Switzerland
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - David B. Sattelle
- Centre for Respiratory Biology, UCL Respiratory Department, Division of Medicine, University College London, Rayne Building, 5 University Street, London WC1E 6JF, UK
| | - José de la Fuente
- SaBio, Instituto de Investigación en Recursos Cinegéticos, IREC-CSIC-UCLM-JCCM, Ronda de Toledo sn, Ciudad Real 13005, Spain
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, 250 McElroy Hall, Stillwater, Oklahama 74078, USA
| | - Jose M. Ribeiro
- Laboratory of Malaria and Vector Research, NIAID, Rockville, Maryland 20852, USA
| | - Karine Megy
- VectorBase/EMBL-EBI, Wellcome Trust Genome Campus, Cambridge CB10 1SD, UK
| | - Jyothi Thimmapuram
- Bioinformatics Core, Purdue University, West Lafayette, Indiana 47907, USA
| | | | | | - Sergey Koren
- J. Craig Venter Institute, Rockville, Maryland 20850, USA
| | | | | | | | | | - Shelby Bidwell
- J. Craig Venter Institute, Rockville, Maryland 20850, USA
| | - Martin P. Hammond
- VectorBase/EMBL-EBI, Wellcome Trust Genome Campus, Cambridge CB10 1SD, UK
| | - Sarah Young
- Genome Sequencing and Analysis Program, Broad Institute, Cambridge, Massachusetts 02142, USA
| | - Qiandong Zeng
- Genome Sequencing and Analysis Program, Broad Institute, Cambridge, Massachusetts 02142, USA
| | - Jenica L. Abrudan
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Francisca C. Almeida
- Departament de Genètica & Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona E-08028, Spain
| | - Nieves Ayllón
- SaBio, Instituto de Investigación en Recursos Cinegéticos, IREC-CSIC-UCLM-JCCM, Ronda de Toledo sn, Ciudad Real 13005, Spain
| | - Ketaki Bhide
- Bioinformatics Core, Purdue University, West Lafayette, Indiana 47907, USA
| | - Brooke W. Bissinger
- Department of Entomology, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Elena Bonzon-Kulichenko
- Vascular Physiopathology, Centro Nacional de Investigaciones Cardiovasculares, Madrid 28029, Spain
| | - Steven D. Buckingham
- Centre for Respiratory Biology, UCL Respiratory Department, Division of Medicine, University College London, Rayne Building, 5 University Street, London WC1E 6JF, UK
| | - Daniel R. Caffrey
- Department of Medicine, Division of Infectious Diseases, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Melissa J. Caimano
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Vincent Croset
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne CH-1015, Switzerland
| | - Timothy Driscoll
- Genetics, Bioinformatics, and Computational Biology Program, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, Virginia 24061, USA
| | - Don Gilbert
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
| | - Joseph J. Gillespie
- Genetics, Bioinformatics, and Computational Biology Program, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, Virginia 24061, USA
| | - Gloria I. Giraldo-Calderón
- Department of Entomology, Purdue University, West Lafayette, Indiana 47907, USA
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Jeffrey M. Grabowski
- Department of Entomology, Purdue University, West Lafayette, Indiana 47907, USA
- Department Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, Indiana 47907, USA
| | - David Jiang
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, USA
| | - Sayed M. S. Khalil
- Department of Microbial Molecular Biology, Agricultural Genetic Engineering Research Institute, Giza 12619, Egypt
| | - Donghun Kim
- Department of Entomology, Texas A&M University, College Station, Texas 77843, USA
| | - Katherine M. Kocan
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, 250 McElroy Hall, Stillwater, Oklahama 74078, USA
| | - Juraj Koči
- Department of Entomology, Kansas State University, Manhattan, Kansas 66506, USA
| | - Richard J. Kuhn
- Department Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Timothy J. Kurtti
- Department of Entomology, University of Minnesota, St Paul, Minnesota 55108, USA
| | - Kristin Lees
- Department of Neurosystems, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Emma G. Lang
- Department of Entomology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Ryan C. Kennedy
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94143, USA
| | - Hyeogsun Kwon
- Department of Entomology, Texas A&M University, College Station, Texas 77843, USA
| | - Rushika Perera
- Department Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Yumin Qi
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, USA
| | - Justin D. Radolf
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Joyce M. Sakamoto
- Department of Entomology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Alejandro Sánchez-Gracia
- Departament de Genètica & Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona E-08028, Spain
| | - Maiara S. Severo
- Department of Entomology, Center for Disease Vector Research, University of California, Riverside, California 92506, USA
| | - Neal Silverman
- Department of Medicine, Division of Infectious Diseases, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Ladislav Šimo
- Department of Entomology, Kansas State University, Manhattan, Kansas 66506, USA
| | - Marta Tojo
- Department of Pathology, Cambridge Genomic Services, University of Cambridge, Cambridge CB2 1QP, UK
- Department of Physiology, School of Medicine-CIMUS-Instituto de Investigaciones Sanitarias, University of Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Cristian Tornador
- Department of Experimental and Health Sciences, Universidad Pompeu Fabra, Barcelona 08003, Spain
| | - Janice P. Van Zee
- Department of Entomology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Jesús Vázquez
- Vascular Physiopathology, Centro Nacional de Investigaciones Cardiovasculares, Madrid 28029, Spain
| | - Filipe G. Vieira
- Departament de Genètica & Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona E-08028, Spain
| | - Margarita Villar
- SaBio, Instituto de Investigación en Recursos Cinegéticos, IREC-CSIC-UCLM-JCCM, Ronda de Toledo sn, Ciudad Real 13005, Spain
| | - Adam R. Wespiser
- Department of Medicine, Division of Infectious Diseases, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Yunlong Yang
- Department of Entomology, Texas A&M University, College Station, Texas 77843, USA
| | - Jiwei Zhu
- Department of Entomology, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Peter Arensburger
- Department of Biological Sciences, California State Polytechnic University, Pomona, California 91768, USA
| | | | - Stephen C. Barker
- Parasitology Section, School of Chemistry & Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Renfu Shao
- GeneCology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore, Queensland 4556, Australia
| | - Evgeny M. Zdobnov
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva 1211, Switzerland
- Swiss Institute of Bioinformatics, Geneva 1211, Switzerland
| | - Frank Hauser
- Department of Biology, Center for Functional and Comparative Insect Genomics, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Cornelis J. P. Grimmelikhuijzen
- Department of Biology, Center for Functional and Comparative Insect Genomics, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Yoonseong Park
- Department of Entomology, Kansas State University, Manhattan, Kansas 66506, USA
| | - Julio Rozas
- Departament de Genètica & Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona E-08028, Spain
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne CH-1015, Switzerland
| | - Joao H. F. Pedra
- Department of Entomology, Center for Disease Vector Research, University of California, Riverside, California 92506, USA
| | - David R. Nelson
- Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
| | - Maria F. Unger
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Jose M. C. Tubio
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton CB10 1SA, UK
- Department of Biochemistry, Genetics and Immunology, University of Vigo, Vigo 36310, Spain
| | - Zhijian Tu
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, USA
| | - Hugh M. Robertson
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Martin Shumway
- J. Craig Venter Institute, Rockville, Maryland 20850, USA
| | - Granger Sutton
- J. Craig Venter Institute, Rockville, Maryland 20850, USA
| | | | - Daniel Lawson
- VectorBase/EMBL-EBI, Wellcome Trust Genome Campus, Cambridge CB10 1SD, UK
| | - Stephen K. Wikel
- Department of Medical Sciences, Frank H. Netter MD School of Medicine at Quinnipiac University, Hamden, Connecticut 06518, USA
| | | | - Claire M. Fraser
- Institute for Genome Sciences, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA
| | - Frank H. Collins
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Bruce Birren
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | | | - Elisabet Caler
- J. Craig Venter Institute, Rockville, Maryland 20850, USA
| | - Catherine A. Hill
- Department of Entomology, Purdue University, West Lafayette, Indiana 47907, USA
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Grassmann AA, McBride AJA, Nally JE, Caimano MJ. Generation of Mammalian Host-adapted Leptospira interrogans by Cultivation in Peritoneal Dialysis Membrane Chamber Implantation in Rats. Bio Protoc 2015; 5:e1536. [PMID: 26258158 DOI: 10.21769/bioprotoc.1536] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Leptospira interrogans can infect a myriad of mammalian hosts, including humans (Bharti et al., 2003; Ko et al., 2009). Following acquisition by a suitable host, leptospires disseminate via the bloodstream to multiple tissues, including the kidneys, where they adhere to and colonize the proximal convoluted renal tubules (Athanazio et al., 2008). Infected hosts shed large number of spirochetes in their urine and the leptospires can survive in different environmental conditions before transmission to another host. Differential gene expression by Leptospira spp. permits adaption to these new conditions. Here we describe a protocol for the cultivation of Leptospira interrogans within Dialysis Membrane Chambers (DMCs) implanted into the peritoneal cavities of Sprague-Dawley rats (Caimano et al., 2014). This technique was originally developed to study mammalian adaption by the Lyme disease spirochete, Borrelia burgdorferi (Akins et al., 1998; Caimano, 2005). The small pore size (8,000 MWCO) of the dialysis membrane tubing used for this procedure permits access to host nutrients but excludes host antibodies and immune effector cells. Given the physiological and environmental similarities between DMCs and the proximal convoluted renal tubule, we reasoned that the DMC model would be suitable for studying in vivo gene expression by L. interrogans. In a 20 to 30 min procedure, DMCs containing virulent leptospires are surgically-implanted into the rat peritoneal cavity. Nine to 11 days post-implantation, DMCs are explanted and organisms recovered. Typically, a single DMC yields ~109 mammalian host-adapted leptospires (Caimano et al., 2014). In addition to providing a facile system for studying the transcriptional and physiologic changes pathogenic L. interrogans undergo within the mammal, the DMC model also provides a rationale basis for selecting new targets for mutagenesis and the identification of novel virulence determinants. Caution: Leptospira interrogans is a BSL-2 level pathogen and known to be excreted in the urine of infected animals. Animals should be handled and disposed of using recommended Animal Biosafety Levels (ABSL) for infectious agents using vertebrate animal guidelines. Note: All protocols using live animals must conform to governmental regulations regarding the care and use of laboratory animals. The success of this protocol is dependent on the proper use of aseptic techniques during all stages of both dialysis membrane chamber preparation and animal surgery.
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Affiliation(s)
- André Alex Grassmann
- Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brasil ; Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Alan John Alexander McBride
- Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brasil
| | - Jarlath E Nally
- Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, Iowa
| | - Melissa J Caimano
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, USA ; Department of Pediatrics, University of Connecticut Health Center, Farmington, Connecticut, USA ; Department of Molecular Biology & Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA
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28
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Iyer R, Caimano MJ, Luthra A, Axline D, Corona A, Iacobas DA, Radolf JD, Schwartz I. Stage-specific global alterations in the transcriptomes of Lyme disease spirochetes during tick feeding and following mammalian host adaptation. Mol Microbiol 2014; 95:509-38. [PMID: 25425211 DOI: 10.1111/mmi.12882] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2014] [Indexed: 12/31/2022]
Abstract
Borrelia burgdorferi, the agent of Lyme disease, is maintained in nature within an enzootic cycle involving a mammalian reservoir and an Ixodes sp. tick vector. The transmission, survival and pathogenic potential of B. burgdorferi depend on the bacterium's ability to modulate its transcriptome as it transits between vector and reservoir host. Herein, we employed an amplification-microarray approach to define the B. burgdorferi transcriptomes in fed larvae, fed nymphs and in mammalian host-adapted organisms cultivated in dialysis membrane chambers. The results show clearly that spirochetes exhibit unique expression profiles during each tick stage and during cultivation within the mammal; importantly, none of these profiles resembles that exhibited by in vitro grown organisms. Profound shifts in transcript levels were observed for genes encoding known or predicted lipoproteins as well as proteins involved in nutrient uptake, carbon utilization and lipid synthesis. Stage-specific expression patterns of chemotaxis-associated genes also were noted, suggesting that the composition and interactivities of the chemotaxis machinery components vary considerably in the feeding tick and mammal. The results as a whole make clear that environmental sensing by B. burgdorferi directly or indirectly drives an extensive and tightly integrated modulation of cell envelope constituents, chemotaxis/motility machinery, intermediary metabolism and cellular physiology. These findings provide the necessary transcriptional framework for delineating B. burgdorferi regulatory pathways throughout the enzootic cycle as well as defining the contribution(s) of individual genes to spirochete survival in nature and virulence in humans.
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Affiliation(s)
- Radha Iyer
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, USA
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29
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Ristow LC, Miller HE, Padmore LJ, Chettri R, Salzman N, Caimano MJ, Rosa PA, Coburn J. The β₃-integrin ligand of Borrelia burgdorferi is critical for infection of mice but not ticks. Mol Microbiol 2012; 85:1105-18. [PMID: 22758390 DOI: 10.1111/j.1365-2958.2012.08160.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
P66 is a Borrelia burgdorferi surface protein with β₃ integrin binding and channel forming activities. In this study, the role of P66 in mammalian and tick infection was examined. B. burgdorferiΔp66 strains were not infectious in wild-type, TLR2⁻/⁻- or MyD88⁻/⁻-deficient mice. Strains with p66 restored to the chromosome restored near wild-type infectivity, while complementation with p66 on a shuttle vector did not restore infectivity. Δp66 mutants are cleared quickly from the site of inoculation, but analyses of cytokine expression and cellular infiltrates at the site of inoculation did not reveal a specific mechanism of clearance. The defect in these mutants cannot be attributed to nutrient limitation or an inability to adapt to the host environment in vivo as Δp66 bacteria were able to survive as well as wild type in dialysis membrane chambers in the rat peritoneum. Δp66 bacteria were able to survive in ticks through the larva to nymph moult, but were non-infectious in mice when delivered by tick bite. Independent lines of evidence do not support any increased susceptibility of the Δp66 strains to factors in mammalian blood. This study is the first to define a B. burgdorferi adhesin as essential for mammalian, but not tick infection.
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Affiliation(s)
- Laura C Ristow
- Graduate Program in Microbiology, Immunology, and Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI, USA
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Dunham-Ems SM, Caimano MJ, Eggers CH, Radolf JD. Borrelia burgdorferi requires the alternative sigma factor RpoS for dissemination within the vector during tick-to-mammal transmission. PLoS Pathog 2012; 8:e1002532. [PMID: 22359504 PMCID: PMC3280991 DOI: 10.1371/journal.ppat.1002532] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 12/28/2011] [Indexed: 11/18/2022] Open
Abstract
While the roles of rpoSBb and RpoS-dependent genes have been studied extensively within the mammal, the contribution of the RpoS regulon to the tick-phase of the Borrelia burgdorferi enzootic cycle has not been examined. Herein, we demonstrate that RpoS-dependent gene expression is prerequisite for the transmission of spirochetes by feeding nymphs. RpoS-deficient organisms are confined to the midgut lumen where they transform into an unusual morphotype (round bodies) during the later stages of the blood meal. We show that round body formation is rapidly reversible, and in vitro appears to be attributable, in part, to reduced levels of Coenzyme A disulfide reductase, which among other functions, provides NAD+ for glycolysis. Our data suggest that spirochetes default to an RpoS-independent program for round body formation upon sensing that the energetics for transmission are unfavorable. Lyme disease, caused by the spirochetal pathogen Borrelia burgdorferi, is the most prevalent arthropod-borne infection in the United States. In order to maintain itself in nature, B. burgdorferi must cycle between its arthropod vector, Ixodes ticks, and a mammalian reservoir, usually a small rodent. Previous studies have demonstrated that the alternative sigma factor RpoS is essential for B. burgdorferi to infect a mammalian host, whereas a role within the tick has never been examined. In this study, we determined that one or more RpoS-dependent genes are required for B. burgdorferi to disseminate through the tick. Using a combination of microscopy techniques, we show that RpoS-deficient organisms are confined to the lumen of the tick midgut during nymphal feeding where they form round bodies, while wild-type spirochetes remain elongated and traverse the midgut to enter the hemolymph and salivary glands en route to the mammalian host.
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Affiliation(s)
- Star M. Dunham-Ems
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Melissa J. Caimano
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Christian H. Eggers
- Department of Biomedical Sciences, Quinnipiac University, Hamden, Connecticut, United States of America
| | - Justin D. Radolf
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America
- Department of Pediatrics, University of Connecticut Health Center, Farmington, Connecticut, United States of America
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut, United States of America
- Department of Immunology, University of Connecticut Health Center, Farmington, Connecticut, United States of America
- * E-mail:
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31
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Abstract
In little more than 30 years, Lyme disease, which is caused by the spirochaete Borrelia burgdorferi, has risen from relative obscurity to become a global public health problem and a prototype of an emerging infection. During this period, there has been an extraordinary accumulation of knowledge on the phylogenetic diversity, molecular biology, genetics and host interactions of B. burgdorferi. In this Review, we integrate this large body of information into a cohesive picture of the molecular and cellular events that transpire as Lyme disease spirochaetes transit between their arthropod and vertebrate hosts during the enzootic cycle.
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Affiliation(s)
- Justin D Radolf
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut 06030, USA.
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32
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Luthra A, Zhu G, Desrosiers DC, Eggers CH, Mulay V, Anand A, McArthur FA, Romano FB, Caimano MJ, Heuck AP, Malkowski MG, Radolf JD. The transition from closed to open conformation of Treponema pallidum outer membrane-associated lipoprotein TP0453 involves membrane sensing and integration by two amphipathic helices. J Biol Chem 2011; 286:41656-41668. [PMID: 21965687 PMCID: PMC3308875 DOI: 10.1074/jbc.m111.305284] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 09/26/2011] [Indexed: 11/06/2022] Open
Abstract
The molecular architecture and composition of the outer membrane (OM) of Treponema pallidum (Tp), the noncultivable agent of venereal syphilis, differ considerably from those of typical Gram-negative bacteria. Several years ago we described TP0453, the only lipoprotein associated with the inner leaflet of the Tp OM. Whereas polypeptides of other treponemal lipoproteins are hydrophilic, non-lipidated TP0453 can integrate into membranes, a property attributed to its multiple amphipathic helices (AHs). Furthermore, membrane integration of the TP0453 polypeptide was found to increase membrane permeability, suggesting the molecule functions in a porin-like manner. To better understand the mechanism of membrane integration of TP0453 and its physiological role in Tp OM biogenesis, we solved its crystal structure and used mutagenesis to identify membrane insertion elements. The crystal structure of TP0453 consists of an α/β/α-fold and includes five stably folded AHs. In high concentrations of detergent, TP0453 transitions from a closed to open conformation by lateral movement of two groups of AHs, exposing a large hydrophobic cavity. Triton X-114 phase partitioning, liposome floatation assay, and bis-1-anilino-8-naphthalenesulfonate binding revealed that two adjacent AHs are critical for membrane sensing/integration. Using terbium-dipicolinic acid complex-loaded large unilamellar vesicles, we found that TP0453 increased efflux of fluorophore only at acidic pH. Gel filtration and cross-linking experiments demonstrated that one AH critical for membrane sensing/insertion also forms a dimeric interface. Based on structural dynamics and comparison with Mycobacterium tuberculosis lipoproteins LprG and LppX, we propose that TP0453 functions as a carrier of lipids, glycolipids, and/or derivatives during OM biogenesis.
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Affiliation(s)
- Amit Luthra
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut 06030
| | - Guangyu Zhu
- Hauptman-Woodward Medical Research Institute and Department of Structural Biology, State University of New York, Buffalo, New York 14203
| | - Daniel C Desrosiers
- Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut 06536
| | - Christian H Eggers
- Departments of Biomedical Sciences, Quinnipiac University, Hamden, Connecticut 06518
| | - Vishwaroop Mulay
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut 06030
| | - Arvind Anand
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut 06030
| | - Fiona A McArthur
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut 06030
| | - Fabian B Romano
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Melissa J Caimano
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut 06030
| | - Alejandro P Heuck
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003; Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Michael G Malkowski
- Hauptman-Woodward Medical Research Institute and Department of Structural Biology, State University of New York, Buffalo, New York 14203
| | - Justin D Radolf
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut 06030; Department of Pediatrics, University of Connecticut Health Center, Farmington, Connecticut 06030; Departments of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut 06030; Department of Immunology, University of Connecticut Health Center, Farmington, Connecticut 06030.
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Eggers CH, Caimano MJ, Malizia RA, Kariu T, Cusack B, Desrosiers DC, Hazlett KRO, Claiborne A, Pal U, Radolf JD. The coenzyme A disulphide reductase of Borrelia burgdorferi is important for rapid growth throughout the enzootic cycle and essential for infection of the mammalian host. Mol Microbiol 2011; 82:679-97. [PMID: 21923763 DOI: 10.1111/j.1365-2958.2011.07845.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
In a microarray analysis of the RpoS regulon in mammalian host-adapted Borrelia burgdorferi, bb0728 (cdr) was found to be dually transcribed by the sigma factors σ(70) and RpoS. The cdr gene encodes a coenzyme A disulphide reductase (CoADR) that reduces CoA-disulphides to CoA in an NADH-dependent manner. Based on the abundance of CoA in B. burgdorferi and the biochemistry of the enzyme, CoADR has been proposed to play a role in the spirochaete's response to reactive oxygen species. To better understand the physiologic function(s) of BbCoADR, we generated a B. burgdorferi mutant in which the cdr gene was disrupted. RT-PCR and 5'-RACE analysis revealed that cdr and bb0729 are co-transcribed from a single transcriptional start site upstream of the bb0729 coding sequence; a shuttle vector containing the bb0729-cdr operon and upstream promoter element was used to complement the cdr mutant. Although the mutant was no more sensitive to hydrogen peroxide than its parent, it did exhibit increased sensitivity to high concentrations of t-butyl-hydroperoxide, an oxidizing compound that damages spirochetal membranes. Characterization of the mutant during standard (15% oxygen, 6% CO(2)) and anaerobic (< 1% O(2) , 9-13% CO(2)) cultivation at 37°C revealed a growth defect under both conditions that was particularly striking during anaerobiosis. The mutant was avirulent by needle inoculation and showed decreased survival in feeding nymphs, but displayed no survival defect in unfed flat nymphs. Based on these results, we propose that BbCoADR is necessary to maintain optimal redox ratios for CoA/CoA-disulphide and NAD(+) /NADH during periods of rapid replication throughout the enzootic cycle, to support thiol-disulphide homeostasis, and to indirectly protect the spirochaete against peroxide-mediated membrane damage; one or more of these functions are essential for infection of the mammalian host by B. burgdorferi.
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Affiliation(s)
- Christian H Eggers
- Department of Biomedical Sciences, Quinnipiac University, Hamden, CT 06518, USA.
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Pappas CJ, Iyer R, Petzke MM, Caimano MJ, Radolf JD, Schwartz I. Borrelia burgdorferi requires glycerol for maximum fitness during the tick phase of the enzootic cycle. PLoS Pathog 2011; 7:e1002102. [PMID: 21750672 PMCID: PMC3131272 DOI: 10.1371/journal.ppat.1002102] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 04/18/2011] [Indexed: 12/02/2022] Open
Abstract
Borrelia burgdorferi, the spirochetal agent of Lyme disease, is a vector-borne pathogen that cycles between a mammalian host and tick vector. This complex life cycle requires that the spirochete modulate its gene expression program to facilitate growth and maintenance in these diverse milieus. B. burgdorferi contains an operon that is predicted to encode proteins that would mediate the uptake and conversion of glycerol to dihydroxyacetone phosphate. Previous studies indicated that expression of the operon is elevated at 23°C and is repressed in the presence of the alternative sigma factor RpoS, suggesting that glycerol utilization may play an important role during the tick phase. This possibility was further explored in the current study by expression analysis and mutagenesis of glpD, a gene predicted to encode glycerol 3-phosphate dehydrogenase. Transcript levels for glpD were significantly lower in mouse joints relative to their levels in ticks. Expression of GlpD protein was repressed in an RpoS-dependent manner during growth of spirochetes within dialysis membrane chambers implanted in rat peritoneal cavities. In medium supplemented with glycerol as the principal carbohydrate, wild-type B. burgdorferi grew to a significantly higher cell density than glpD mutant spirochetes during growth in vitro at 25°C. glpD mutant spirochetes were fully infectious in mice by either needle or tick inoculation. In contrast, glpD mutants grew to significantly lower densities than wild-type B. burgdorferi in nymphal ticks and displayed a replication defect in feeding nymphs. The findings suggest that B. burgdorferi undergoes a switch in carbohydrate utilization during the mammal to tick transition. Further, the results demonstrate that the ability to utilize glycerol as a carbohydrate source for glycolysis during the tick phase of the infectious cycle is critical for maximal B. burgdorferi fitness. Borrelia burgdorferi is the vector-borne pathogen that causes Lyme disease. It has a complex life cycle that involves growth in a tick vector and a mammalian host — two diverse environments that present B. burgdorferi with alternative carbohydrate sources for support of growth. Previous studies suggested that glycerol may be an important nutrient in the tick vector. Here we show that genes predicted to be involved in glycerol metabolism have significantly elevated expression during all tick stages. Repression of expression in the mammalian host is dependent on the alternative sigma factor, RpoS. A mutant that cannot convert glycerol into dihydroxyacetone phosphate to support glycolysis was able to infect mice. In contrast, the mutant was present at significantly lower levels in nymphal ticks, its replication was delayed during nymphal feeding and longer feeding times were required for transmission from nymph to mouse. The results demonstrate that the ability to utilize glycerol as a carbohydrate source for glycolysis during the tick phase of the infectious cycle is critical for maximal B. burgdorferi fitness.
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Affiliation(s)
- Christopher J. Pappas
- Department of Microbiology and Immunology, New York Medical College, Valhalla, New York, United States of America
| | - Radha Iyer
- Department of Microbiology and Immunology, New York Medical College, Valhalla, New York, United States of America
| | - Mary M. Petzke
- Department of Microbiology and Immunology, New York Medical College, Valhalla, New York, United States of America
| | - Melissa J. Caimano
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Justin D. Radolf
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut, United States of America
- Department of Pediatrics, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Ira Schwartz
- Department of Microbiology and Immunology, New York Medical College, Valhalla, New York, United States of America
- * E-mail:
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Desrosiers DC, Anand A, Luthra A, Dunham-Ems SM, LeDoyt M, Cummings MAD, Eshghi A, Cameron CE, Cruz AR, Salazar JC, Caimano MJ, Radolf JD. TP0326, a Treponema pallidum β-barrel assembly machinery A (BamA) orthologue and rare outer membrane protein. Mol Microbiol 2011; 80:1496-515. [PMID: 21488980 DOI: 10.1111/j.1365-2958.2011.07662.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Definitive identification of Treponema pallidum rare outer membrane proteins (OMPs) has long eluded researchers. TP0326, the sole protein in T. pallidum with sequence homology to a Gram-negative OMP, belongs to the BamA family of proteins essential for OM biogenesis. Structural modelling predicted that five polypeptide transport-associated (POTRA) domains comprise the N-terminus of TP0326, while the C-terminus forms an 18-stranded amphipathic β-barrel. Circular dichroism, heat modifiability by SDS-PAGE, Triton X-114 phase partitioning and liposome incorporation supported these topological predictions and confirmed that the β-barrel is responsible for the native protein's amphiphilicity. Expression analyses revealed that native TP0326 is expressed at low abundance, while a protease-surface accessibility assay confirmed surface exposure. Size-exclusion chromatography and blue native polyacrylamide gel electrophoresis revealed a modular Bam complex in T. pallidum larger than that of Escherichia coli. Non-orthologous ancillary factors and self-association of TP0326 via its β-barrel may both contribute to the Bam complex. T. pallidum-infected rabbits mount a vigorous antibody response to both POTRA and β-barrel portions of TP0326, whereas humans with secondary syphilis respond predominantly to POTRA. The syphilis spirochaete appears to have devised a stratagem for harnessing the Bam pathway while satisfying its need to limit surface antigenicity.
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Affiliation(s)
- Daniel C Desrosiers
- Department of Medicine, University of Connecticut Health Center, Farmington, CT 06040, USA
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Balic A, Aguila HL, Caimano MJ, Francone VP, Mina M. Characterization of stem and progenitor cells in the dental pulp of erupted and unerupted murine molars. Bone 2010; 46:1639-51. [PMID: 20193787 PMCID: PMC2881695 DOI: 10.1016/j.bone.2010.02.019] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 02/12/2010] [Accepted: 02/18/2010] [Indexed: 12/15/2022]
Abstract
In the past few years there have been significant advances in the identification of putative stem cells also referred to as "mesenchymal stem cells" (MSC) in dental tissues including the dental pulp. It is thought that MSC in dental pulp share certain similarities with MSC isolated from other tissues. However, cells in dental pulp are still poorly characterized. This study focused on the characterization of progenitor and stem cells in dental pulps of erupted and unerupted mice molars. Our study showed that dental pulps from unerupted molars contain a significant number of cells expressing CD90+/CD45-, CD117+/CD45-, Sca-1+/CD45- and little if any CD45+ cells. Our in vitro functional studies showed that dental pulp cells from unerupted molars displayed extensive osteo-dentinogenic potential but were unable to differentiate into chondrocytes and adipocytes. Dental pulps from erupted molars displayed a reduced number of cells, contained a higher percentage of CD45+ and a lower percentage of cells expressing CD90+/CD45-, CD117+/CD45- as compared to unerupted molars. In vitro functional assays demonstrated the ability of a small fraction of cells to differentiate into odontoblasts, osteoblasts, adipocytes and chondrocytes. There was a significant reduction in the osteo-dentinogenic potential of the pulp cells derived from erupted molars compared to unerupted molars. Furthermore, the adipogenic and chondrogenic differentiation of pulp cells from erupted molars was dependent on a long induction period and were infrequent. Based on these findings we propose that the dental pulp of the erupted molars contain a small population of multipotent cells, whereas the dental pulp of the unerupted molars does not contain multipotent cells but is enriched in osteo-dentinogenic progenitors engaged in the formation of coronal and radicular odontoblasts.
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Affiliation(s)
- Anamaria Balic
- Department of Craniofacial Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT
| | - H. Leonardo Aguila
- Department of Immunology, School of Medicine, University of Connecticut Health Center, Farmington, CT
| | - Melissa J. Caimano
- Department of Medicine, School of Medicine, University of Connecticut Health Center, Farmington, CT
| | - Victor P. Francone
- Department of Neuroscience, School of Medicine, University of Connecticut Health Center, Farmington, CT
| | - Mina Mina
- Department of Craniofacial Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT
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Dunham-Ems SM, Caimano MJ, Pal U, Wolgemuth CW, Eggers CH, Balic A, Radolf JD. Live imaging reveals a biphasic mode of dissemination of Borrelia burgdorferi within ticks. J Clin Invest 2009; 119:3652-65. [PMID: 19920352 DOI: 10.1172/jci39401] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Accepted: 09/30/2009] [Indexed: 01/17/2023] Open
Abstract
Lyme disease is caused by transmission of the spirochete Borrelia burgdorferi from ticks to humans. Although much is known about B. burgdorferi replication, the routes and mechanisms by which it disseminates within the tick remain unclear. To better understand this process, we imaged live, infectious B. burgdorferi expressing a stably integrated, constitutively expressed GFP reporter. Using isolated tick midguts and salivary glands, we observed B. burgdorferi progress through the feeding tick via what we believe to be a novel, biphasic mode of dissemination. In the first phase, replicating spirochetes, positioned at varying depths throughout the midgut at the onset of feeding, formed networks of nonmotile organisms that advanced toward the basolateral surface of the epithelium while adhering to differentiating, hypertrophying, and detaching epithelial cells. In the second phase of dissemination, the nonmotile spirochetes transitioned into motile organisms that penetrated the basement membrane and entered the hemocoel, then migrated to and entered the salivary glands. We designated the first phase of dissemination "adherence-mediated migration" and provided evidence that it involves the inhibition of spirochete motility by one or more diffusible factors elaborated by the feeding tick midgut. Our studies, which we believe are the first to relate the transmission dynamics of spirochetes to the complex morphological and developmental changes that the midgut and salivary glands undergo during engorgement, challenge the conventional viewpoint that dissemination of Lyme disease-causing spirochetes within ticks is exclusively motility driven.
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Affiliation(s)
- Star M Dunham-Ems
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, USA
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38
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Salazar JC, Duhnam-Ems S, La Vake C, Cruz AR, Moore MW, Caimano MJ, Velez-Climent L, Shupe J, Krueger W, Radolf JD. Activation of human monocytes by live Borrelia burgdorferi generates TLR2-dependent and -independent responses which include induction of IFN-beta. PLoS Pathog 2009; 5:e1000444. [PMID: 19461888 PMCID: PMC2679197 DOI: 10.1371/journal.ppat.1000444] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Accepted: 04/24/2009] [Indexed: 11/19/2022] Open
Abstract
It is widely believed that innate immune responses to Borrelia burgdorferi (Bb) are primarily triggered by the spirochete's outer membrane lipoproteins signaling through cell surface TLR1/2. We recently challenged this notion by demonstrating that phagocytosis of live Bb by peripheral blood mononuclear cells (PBMCs) elicited greater production of proinflammatory cytokines than did equivalent bacterial lysates. Using whole genome microarrays, we show herein that, compared to lysates, live spirochetes elicited a more intense and much broader transcriptional response involving genes associated with diverse cellular processes; among these were IFN-β and a number of interferon-stimulated genes (ISGs), which are not known to result from TLR2 signaling. Using isolated monocytes, we demonstrated that cell activation signals elicited by live Bb result from cell surface interactions and uptake and degradation of organisms within phagosomes. As with PBCMs, live Bb induced markedly greater transcription and secretion of TNF-α, IL-6, IL-10 and IL-1β in monocytes than did lysates. Secreted IL-18, which, like IL-1β, also requires cleavage by activated caspase-1, was generated only in response to live Bb. Pro-inflammatory cytokine production by TLR2-deficient murine macrophages was only moderately diminished in response to live Bb but was drastically impaired against lysates; TLR2 deficiency had no significant effect on uptake and degradation of spirochetes. As with PBMCs, live Bb was a much more potent inducer of IFN-β and ISGs in isolated monocytes than were lysates or a synthetic TLR2 agonist. Collectively, our results indicate that the enhanced innate immune responses of monocytes following phagocytosis of live Bb have both TLR2-dependent and -independent components and that the latter induce transcription of type I IFNs and ISGs. Lyme disease is a tick-borne infectious disorder caused by the spirochetal pathogen Borrelia burgdorferi (Bb). Innate immune responses to Bb are thought to be triggered by the spirochete's outer membrane lipoproteins signaling through cell surface toll-like receptors (TLR1/2). Using a whole genome microarray technique, we showed that live spirochetes elicited a more intense and broader immune response in human peripheral blood mononuclear cells (PBMCs) than could be explained simply by TLR1/2 cell surface stimulation. Of particular interest, live Bb also uniquely induced transcription of type I interferons. In similarly stimulated isolated human monocytes, live Bb generated a greater production of pro- and anti-inflammatory cytokines (TNF-α, IL-6, IL-10 and IL-1β), as well as interferon-β (IFN-β). Secreted IL-18, which like IL-1β requires cytosolic cleavage of its inactive form by activated caspase-1, was generated only in response to live Bb. The cytosolic responses occurred despite evidence that phagocytosed spirochetes were rapidly degraded in phagosomal vacuoles, and unable to escape unscathed into the cell cytosol. We conclude that the innate immune signals generated in human monocytes by phagocytosed spirochetes allow the host to control the bacterium through a number of non-exclusive pathways, that are both TLR2-dependent and -independent, and include a type I interferon response.
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Affiliation(s)
- Juan C. Salazar
- Connecticut Children's Medical Center, Division of Pediatric Infectious Diseases, Hartford, Connecticut, United States of America
- Department of Pediatrics, University of Connecticut Health Center, Farmington, Connecticut, United States of America
- * E-mail:
| | - Star Duhnam-Ems
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Carson La Vake
- Department of Pediatrics, University of Connecticut Health Center, Farmington, Connecticut, United States of America
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Adriana R. Cruz
- Centro Internacional de Entrenamiento e Investigaciones Medicas, Cali, Colombia
| | - Meagan W. Moore
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Melissa J. Caimano
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Leonor Velez-Climent
- Connecticut Children's Medical Center, Division of Pediatric Infectious Diseases, Hartford, Connecticut, United States of America
- Department of Pediatrics, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Jonathan Shupe
- Department of Pediatrics, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Winfried Krueger
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Justin D. Radolf
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut, United States of America
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Abstract
Borrelia burgdorferi must adapt physiologically to two markedly different host milieus and efficiently transit between its mammalian host and arthropod vector during tick feeding. Differential production of lipoproteins is essential for spirochaetes to survive, multiply and migrate within both hosts. Outer-surface protein C (OspC), which is induced during the blood meal, is critical for transmission of Lyme disease spirochaetes by nymphal ticks. Its biological function is poorly understood, however, despite the fact that its crystal structure has been solved. Evidence has accumulated that OspC blocks clearance of spirochaetes following inoculation in skin, and it is thought to do so by facilitating evasion of innate immunity. The study by Liang and co-workers in this edition of Molecular Microbiology extends this work by showing that OspC prevents early elimination and promotes dissemination. Surprisingly, they also show that unrelated borrelial outer-surface lipoproteins can replace these functions in an ospC mutant. They propose that an abundance of lipoprotein(s) is needed to stabilize the borrelial outer membrane against innate defences. This provocative work clearly runs counter to prevailing orthodoxies of bacterial pathogenesis. It also points the way towards future studies that will clarify the 'partially specific' roles of this enigmatic molecule in Lyme disease pathogenesis.
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Affiliation(s)
- Justin D Radolf
- Department of Medicine, University of Connecticut Health Center, Farmington, CT 06030-3715, USA.
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Caimano MJ, Iyer R, Eggers CH, Gonzalez C, Morton EA, Gilbert MA, Schwartz I, Radolf JD. Analysis of the RpoS regulon in Borrelia burgdorferi in response to mammalian host signals provides insight into RpoS function during the enzootic cycle. Mol Microbiol 2007; 65:1193-217. [PMID: 17645733 PMCID: PMC2967192 DOI: 10.1111/j.1365-2958.2007.05860.x] [Citation(s) in RCA: 210] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Borrelia burgdorferi (Bb) adapts to its arthropod and mammalian hosts by altering its transcriptional and antigenic profiles in response to environmental signals associated with each of these milieus. In studies presented here, we provide evidence to suggest that mammalian host signals are important for modulating and maintaining both the positive and negative aspects of mammalian host adaptation mediated by the alternative sigma factor RpoS in Bb. Although considerable overlap was observed between genes induced by RpoS during growth within the mammalian host and following temperature-shift, comparative microarray analyses demonstrated unequivocally that RpoS-mediated repression requires mammalian host-specific signals. A substantial portion of the in vivo RpoS regulon was uniquely upregulated within dialysis membrane chambers, further underscoring the importance of host-derived environmental stimuli for differential gene expression in Bb. Expression profiling of genes within the RpoS regulon by quantitative reverse transcription polymerase chain reaction (qRT-PCR) revealed a level of complexity to RpoS-dependent gene regulation beyond that observed by microarray, including a broad range of expression levels and the presence of genes whose expression is only partially dependent on RpoS. Analysis of Bb-infected ticks by qRT-PCR established that expression of rpoS is induced during the nymphal blood meal but not within unfed nymphs or engorged larvae. Together, these data have led us to postulate that RpoS acts as a gatekeeper for the reciprocal regulation of genes involved in the establishment of infection within the mammalian host and the maintenance of spirochetes within the arthropod vector.
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Affiliation(s)
- Melissa J Caimano
- Department of Medicine, University of Connecticut Health Center, Farmington, CT 06030, USA.
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Mulay V, Caimano MJ, Liveris D, Desrosiers DC, Radolf JD, Schwartz I. Borrelia burgdorferi BBA74, a periplasmic protein associated with the outer membrane, lacks porin-like properties. J Bacteriol 2006; 189:2063-8. [PMID: 17189354 PMCID: PMC1855751 DOI: 10.1128/jb.01239-06] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The outer membrane of Borrelia burgdorferi, the causative agent of Lyme disease, contains very few integral membrane proteins, in contrast to other gram-negative bacteria. BBA74, a Borrelia burgdorferi plasmid-encoded protein, was proposed to be an integral outer membrane protein with putative porin function and designated as a 28-kDa outer membrane-spanning porin (Oms28). In this study, the biophysical properties of BBA74 and its subcellular localization were investigated. BBA74 is posttranslationally modified by signal peptidase I cleavage to a mature 25-kDa protein. The secondary structure of BBA74 as determined by circular dichroism spectroscopy consists of at least 78% alpha-helix with little beta-sheet structure. BBA74 in intact B. burgdorferi cells was insensitive to proteinase K digestion, and indirect immunofluorescence microscopy showed that BBA74 was not exposed on the cell surface. Triton X-114 extraction of outer membrane vesicle preparations indicated that BBA74 is not an integral membrane protein. Taken together, the data indicate that BBA74 is a periplasmic, outer membrane-associated protein that lacks properties typically associated with porins.
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Affiliation(s)
- Vishwaroop Mulay
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
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42
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Eggers CH, Caimano MJ, Radolf JD. Sigma factor selectivity in Borrelia burgdorferi: RpoS recognition of the ospE/ospF/elp promoters is dependent on the sequence of the -10 region. Mol Microbiol 2006; 59:1859-75. [PMID: 16553889 DOI: 10.1111/j.1365-2958.2006.05066.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Members of the ospE/ospF/elp lipoprotein gene families of Borrelia burgdorferi, the Lyme disease agent, are transcriptionally upregulated in response to the influx of blood into the midgut of an infected tick. We recently have demonstrated that despite the high degree of similarity between the promoters of the ospF (P(ospF)) and ospE (P(ospE)) genes of B. burgdorferi strain 297, the differential expression of ospF is RpoS-dependent, while ospE is controlled by sigma(70). Herein we used wild-type and RpoS-deficient strains of B. burgdorferi and Escherichia coli to analyse transcriptional reporters consisting of a green fluorescent protein (gfp) gene fused to P(ospF), P(ospE), or two hybrid promoters in which the -10 regions of P(ospF) and P(ospE) were switched [P(ospF ) ((E - 10)) and P(ospE) ((F - 10)) respectively]. We found that the P(ospF)-10 region is both necessary and sufficient for RpoS-dependent recognition in B. burgdorferi, while sigma(70) specificity for P(ospE) is dependent on elements outside of the -10 region. In E. coli, sigma factor selectivity for these promoters was much more permissive, with expression of each being primarily due to sigma(70). Alignment of the sequences upstream of each of the ospE/ospF/elp genes from B. burgdorferi strains 297 and B31 revealed that two B31 ospF paralogues [erpK (BBM38) and erpL (BBO39)] have -10 regions virtually identical to that of P(ospF). Correspondingly, expression of gfp reporters based on the erpK and erpL promoters was RpoS-dependent. Thus, the sequence of the P(ospF)-10 region appears to serve as a motif for RpoS recognition, the first described for any B. burgdorferi promoter. Taken together, our data support the notion that B. burgdorferi utilizes sequence differences at the -10 region as one mechanism for maintaining the transcriptional integrity of RpoS-dependent and -independent genes activated at the onset of tick feeding.
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Affiliation(s)
- Christian H Eggers
- Department of Medicine, University of Connecticut Health Center, Farmington, 06030, USA.
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Caimano MJ, Eggers CH, Gonzalez CA, Radolf JD. Alternate sigma factor RpoS is required for the in vivo-specific repression of Borrelia burgdorferi plasmid lp54-borne ospA and lp6.6 genes. J Bacteriol 2005; 187:7845-52. [PMID: 16267308 PMCID: PMC1280317 DOI: 10.1128/jb.187.22.7845-7852.2005] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
While numerous positively regulated loci have been characterized during the enzootic cycle of Borrelia burgdorferi, very little is known about the mechanism(s) involved in the repression of borrelial loci either during tick feeding or within the mammalian host. Here, we report that the alternative sigma factor RpoS is required for the in vivo-specific repression of at least two RpoD-dependent B. burgdorferi loci, ospA and lp6.6. The downregulation of ospA and Ip6.6 appears to require either a repressor molecule whose expression is RpoS dependent or an accessory factor which enables RpoS to directly interact with the ospA and Ip6.6 promoter elements, thereby blocking transcription by RpoD. The central role for RpoS during the earliest stages of host adaptation suggests that tick feeding imparts signals to spirochetes that trigger the RpoS-dependent repression, as well as expression, of in vivo-specific virulence factors critical for the tick-to-mammalian host transition.
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Affiliation(s)
- Melissa J Caimano
- Department of Medicine, University of Connecticut Health Center, Farmington, 06030-3715, USA.
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Abstract
In order to be sustained within its enzootic cycle, B. burgdorferi must adapt to two strikingly different environments, the arthropod vector and the mammalian host. The ability to rapidly adapt to environmental changes is therefore presumed to be central to spirochete survival and pathogenic programs. Indeed, it has now been well established that tick feeding initiates extensive changes in both gene expression and protein composition, collectively referred to as "host adaptation," a process that is thought to continue throughout infection. The paucibacillary nature of borrelial infections, however, has hampered our ability to study this bacterium in vivo. To circumvent this limitation, an animal model was developed for obtaining sufficient numbers of organisms to directly examine differential gene expression and antigenic composition of B. burgdorferi within the context of the mammalian host. The DMC model allows for a direct comparison of host-adapted B. burgdorferi and their in vitro-cultivated counterparts.
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Affiliation(s)
- Melissa J Caimano
- University of Connecticut Health Center, Farmington, Connecticut, USA
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Benhnia MREI, Wroblewski D, Akhtar MN, Patel RA, Lavezzi W, Gangloff SC, Goyert SM, Caimano MJ, Radolf JD, Sellati TJ. Signaling through CD14 attenuates the inflammatory response to Borrelia burgdorferi, the agent of Lyme disease. J Immunol 2005; 174:1539-48. [PMID: 15661914 DOI: 10.4049/jimmunol.174.3.1539] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Lyme disease is a chronic inflammatory disorder caused by the spirochetal bacterium, Borrelia burgdorferi. In vitro evidence suggests that binding of spirochetal lipoproteins to CD14, a pattern recognition receptor expressed on monocytes/macrophages and polymorphonuclear cells, is a critical requirement for cellular activation and the subsequent release of proinflammatory cytokines that most likely contribute to symptomatology and clinical manifestations. To test the validity of this notion, we assessed the impact of CD14 deficiency on Lyme disease in C3H/HeN mice. Contrary to an anticipated diminution in pathology, CD14(-/-) mice exhibited more severe and persistent inflammation than did CD14(+/+) mice. This disparity reflects altered gene regulation within immune cells that may engender the higher bacterial burden and serum cytokine levels observed in CD14(-/-) mice. Comparing their in vitro stimulatory activity, live spirochetes, but not lysed organisms, were a potent CD14-independent stimulus of cytokine production, triggering an exaggerated response by CD14(-/-) macrophages. Collectively, our in vivo and in vitro findings support the provocative notion that: 1) pattern recognition by CD14 is entirely dispensable for elaboration of an inflammatory response to B. burgdorferi, and 2) CD14-independent signaling pathways are inherently more destructive than CD14-dependent pathways. Continued study of CD14-independent signaling pathways may provide mechanistic insight into the inflammatory processes that underlie development of chronic inflammation.
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Caimano MJ, Eggers CH, Hazlett KRO, Radolf JD. RpoS is not central to the general stress response in Borrelia burgdorferi but does control expression of one or more essential virulence determinants. Infect Immun 2004; 72:6433-45. [PMID: 15501774 PMCID: PMC523033 DOI: 10.1128/iai.72.11.6433-6445.2004] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Borrelia burgdorferi, the Lyme disease spirochete, undergoes dramatic changes in antigenic composition as it cycles between its arthropod and mammalian hosts. A growing body of evidence suggests that these changes reflect, at least in part, the need for spirochetes to adapt to the physiological stresses imposed by abrupt changes in environmental conditions and nutrient availability. In many microorganisms, global responses are mediated by master regulators such as alternative sigma factors, with Escherichia coli RpoS (sigmaS) serving as a prototype. The importance of this transcriptional activator in other bacteria, coupled with the report by Hubner et al. (A. Hubner, X. Yang, D. M. Nolen, T. G. Popova, F. C. Cabello, and M. V. Norgard, Proc. Natl. Acad. Sci. USA 98:12724-12729, 2001) demonstrating that the borrelial RpoS ortholog controls expression of OspC and decorin-binding protein A (DbpA), prompted us to examine more closely the roles of RpoS-dependent and -independent differential gene expression in physiological adaptation by the Lyme disease spirochete. We observed that B. burgdorferi rpoS (rpoSBb) was induced following temperature shift and transcript levels were further enhanced by reduced pH (pH 6.8). Using quantitative real-time reverse transcription-PCR (RT-PCR), we demonstrated that, in contrast to its ortholog (rpoSEc) in Escherichia coli, rpoSBb was expressed at significant levels in B. burgdorferi throughout all phases of growth following temperature shift. By comparing a B. burgdorferi strain 297 rpoSBb mutant to its wild-type counterpart, we determined that RpoSBb was not required for survival following exposure to a wide range of environmental stresses (i.e., temperature shift, serum starvation, increased osmolality, reactive oxygen intermediates, and increased or reduced oxygen tension), although the mutant was more sensitive to extremes of pH. While B. burgdorferi strains lacking RpoS were able to survive within intraperitoneal dialysis membrane chambers at a level equivalent to that of the wild type, they were avirulent in mice. Lastly, RT-PCR analysis of the ospE-ospF-elp paralogous lipoprotein families complements earlier findings that many temperature-inducible borrelial loci are controlled in an RpoSBb-independent manner. Together, these data point to fundamental differences between the role(s) of RpoS in B. burgdorferi and that in E. coli. Rather than functioning as a master regulator, RpoSBb appears to serve as a stress-responsive activator of a subset of virulence determinants that, together with the RpoS-independent, differentially expressed regulon, encompass the spirochete's genetic programs required for mammalian host adaptation.
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Affiliation(s)
- Melissa J Caimano
- Center for Microbial Pathogenesis, University of Connecticut Health Center, 263 Farmington Ave., Farmington 06030-3710, USA.
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Abstract
Borrelia burgdorferi, the causative agent of Lyme disease, encodes an RpoS ortholog (RpoS(Bb)) that controls the temperature-inducible differential expression of at least some of the spirochete's lipoprotein genes, including ospC and dbpBA. To begin to dissect the determinants of RpoS(Bb) recognition of, and selectivity for, its dependent promoters, we linked a green fluorescent protein reporter to the promoter regions of several B. burgdorferi genes with well-characterized expression patterns. Consistent with the expression patterns of the native genes/proteins in B. burgdorferi strain 297, we found that expression of the ospC, dbpBA, and ospF reporters in the spirochete was RpoS(Bb) dependent, while the ospE and flaB reporters were RpoS(Bb) independent. To compare promoter recognition by RpoS(Bb) with that of the prototype RpoS (RpoS(Ec)), we also introduced our panel of constructs into Escherichia coli. In this surrogate, maximal expression from the ospC, dbpBA, and ospF promoters clearly required RpoS, although in the absence of RpoS(Ec) the ospF promoter was weakly recognized by another E. coli sigma factor. Furthermore, RpoS(Bb) under the control of an inducible promoter was able to complement an E. coli rpoS mutant, although RpoS(Ec) and RpoS(Bb) each initiated greater activity from their own dependent promoters than they did from those of the heterologous sigma factor. Genetic analysis of the ospC promoter demonstrated that (i) the T(-14) in the presumptive -10 region plays an important role in sigma factor recognition in both organisms but is not as critical for transcriptional initiation by RpoS(Bb) as it is for RpoS(Ec); (ii) the nucleotide at the -15 position determines RpoS or sigma(70) selectivity in E. coli but does not serve the same function in B. burgdorferi; and (iii) the 110-bp region upstream of the core promoter is not required for RpoS(Ec)- or RpoS(Bb)-dependent activity in E. coli but is required for maximal expression from this promoter in B. burgdorferi. Taken together, the results of our studies suggest that the B. burgdorferi and E. coli RpoS proteins are able to catalyze transcription from RpoS-dependent promoters of either organism, but at least some of the nucleotide elements involved in transcriptional initiation and sigma factor selection in B. burgdorferi play a different role than has been described for E. coli.
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Affiliation(s)
- Christian H Eggers
- Center for Microbial Pathogenesis, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3710, USA.
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Grimm D, Eggers CH, Caimano MJ, Tilly K, Stewart PE, Elias AF, Radolf JD, Rosa PA. Experimental assessment of the roles of linear plasmids lp25 and lp28-1 of Borrelia burgdorferi throughout the infectious cycle. Infect Immun 2004; 72:5938-46. [PMID: 15385497 PMCID: PMC517563 DOI: 10.1128/iai.72.10.5938-5946.2004] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2004] [Revised: 05/19/2004] [Accepted: 07/16/2004] [Indexed: 11/20/2022] Open
Abstract
Borrelia burgdorferi, which causes Lyme disease in humans, has an unusual genome composed of a linear chromosome and up to 21 extrachromosomal elements. Experimental data suggest that two of these elements, linear plasmids lp25 and lp28-1, play essential roles for infectivity in mice. In this study, we prove the essential natures of these two plasmids by selectively displacing lp25 or lp28-1 in an infectious wild-type clone with incompatible shuttle vectors derived from the native plasmids, rendering the respective transformants noninfectious to mice. Conversely, restoration of plasmid lp25 or lp28-1 in noninfectious clones that naturally lack the corresponding plasmid reestablished infectivity in mice. This approach establishes the ability to manipulate the plasmid content of strains by eliminating or introducing entire plasmids in B. burgdorferi and will be valuable in assessing the roles of plasmids even in unsequenced B. burgdorferi strains.
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Affiliation(s)
- Dorothee Grimm
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, USA
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Blevins JS, Revel AT, Caimano MJ, Yang XF, Richardson JA, Hagman KE, Norgard MV. The luxS gene is not required for Borrelia burgdorferi tick colonization, transmission to a mammalian host, or induction of disease. Infect Immun 2004; 72:4864-7. [PMID: 15271949 PMCID: PMC470628 DOI: 10.1128/iai.72.8.4864-4867.2004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
luxS mutants of Borrelia burgdorferi strain 297 naturally colonized their arthropod (Ixodes scapularis) vector, were maintained in ticks throughout the molting process (larvae to nymphs), were tick transmitted to uninfected mice, and elicited histopathology in mice indistinguishable from that induced by wild-type B. burgdorferi.
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Affiliation(s)
- Jon S Blevins
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, 75390, USA
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Liang FT, Caimano MJ, Radolf JD, Fikrig E. Borrelia burgdorferi outer surface protein (osp) B expression independent of ospA. Microb Pathog 2004; 37:35-40. [PMID: 15194158 DOI: 10.1016/j.micpath.2004.02.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2003] [Revised: 02/27/2004] [Accepted: 02/29/2004] [Indexed: 11/21/2022]
Abstract
The outer surface proteins (Osp) A and B are two important lipoproteins of Borrelia burgdorferi, the Lyme disease spirochete. Extensive in vitro studies indicate that ospB shares a common promoter with ospA and thus these two lipoprotein genes are coordinately transcribed. We show here that B. burgdorferi expresses ospB at much higher levels than ospA during experimental murine infection. The ratio of ospA and ospB mRNA transcripts was 3.5:1 in tick-adapted spirochetes while B. burgdorferi matched every ospA mRNA with up to 70 ospB transcripts during murine infection. This was consistent with the analysis of antibody responses to the two lipoproteins, which showed a more frequent OspB response than OspA during chronic murine infection.
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MESH Headings
- Animals
- Antibodies, Bacterial/blood
- Antigens, Bacterial/biosynthesis
- Antigens, Bacterial/genetics
- Antigens, Bacterial/immunology
- Antigens, Surface/biosynthesis
- Antigens, Surface/genetics
- Antigens, Surface/immunology
- Bacterial Outer Membrane Proteins/biosynthesis
- Bacterial Outer Membrane Proteins/genetics
- Bacterial Outer Membrane Proteins/immunology
- Bacterial Vaccines
- Borrelia burgdorferi/genetics
- Borrelia burgdorferi/growth & development
- Borrelia burgdorferi/immunology
- Borrelia burgdorferi/metabolism
- Disease Models, Animal
- Gene Expression Regulation, Bacterial
- Lipoproteins/biosynthesis
- Lipoproteins/genetics
- Lipoproteins/immunology
- Lyme Disease/microbiology
- Mice
- Mice, Inbred BALB C
- Mice, SCID
- Promoter Regions, Genetic
- RNA, Bacterial/analysis
- RNA, Bacterial/isolation & purification
- RNA, Messenger/analysis
- RNA, Messenger/isolation & purification
- Ticks/microbiology
- Transcription, Genetic
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Affiliation(s)
- Fang Ting Liang
- Section of Rheumatology, Department of Internal Medicine, Yale University School of Medicine, 300 Cedar Street, New Haven, CT 06520-8031, USA
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