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Rogovskyy AS, Casselli T, Tourand Y, Jones CR, Owen JP, Mason KL, Scoles GA, Bankhead T. Evaluation of the Importance of VlsE Antigenic Variation for the Enzootic Cycle of Borrelia burgdorferi. PLoS One 2015; 10:e0124268. [PMID: 25893989 PMCID: PMC4404307 DOI: 10.1371/journal.pone.0124268] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 03/11/2015] [Indexed: 11/30/2022] Open
Abstract
Efficient acquisition and transmission of Borrelia burgdorferi by the tick vector, and the ability to persistently infect both vector and host, are important elements for the life cycle of the Lyme disease pathogen. Previous work has provided strong evidence implicating the significance of the vls locus for B. burgdorferi persistence. However, studies involving vls mutant clones have thus far only utilized in vitro-grown or host-adapted spirochetes and laboratory strains of mice. Additionally, the effects of vls mutation on tick acquisition and transmission has not yet been tested. Thus, the importance of VlsE antigenic variation for persistent infection of the natural reservoir host, and for the B. burgdorferi enzootic life cycle in general, has not been examined to date. In the current work, Ixodes scapularis and Peromyscus maniculatus were infected with different vls mutant clones to study the importance of the vls locus for the enzootic cycle of the Lyme disease pathogen. The findings highlight the significance of the vls system for long-term infection of the natural reservoir host, and show that VlsE antigenic variability is advantageous for efficient tick acquisition of B. burgdorferi from the mammalian reservoir. The data also indicate that the adaptation state of infecting spirochetes influences B. burgdorferi avoidance from host antibodies, which may be in part due to its respective VlsE expression levels. Overall, the current findings provide the most direct evidence on the importance of VlsE for the enzootic cycle of Lyme disease spirochetes, and underscore the significance of VlsE antigenic variation for maintaining B. burgdorferi in nature.
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Affiliation(s)
- Artem S. Rogovskyy
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, United States of America
| | - Timothy Casselli
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, United States of America
| | - Yvonne Tourand
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, United States of America
| | - Cami R. Jones
- Department of Entomology, Washington State University, Pullman, Washington, United States of America
| | - Jeb P. Owen
- Department of Entomology, Washington State University, Pullman, Washington, United States of America
| | - Kathleen L. Mason
- Animal Disease Research Unit, USDA-ARS, Washington State University, Pullman, Washington, United States of America
| | - Glen A. Scoles
- Animal Disease Research Unit, USDA-ARS, Washington State University, Pullman, Washington, United States of America
| | - Troy Bankhead
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, United States of America
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
- * E-mail:
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Stewart PE, Wang X, Bueschel DM, Clifton DR, Grimm D, Tilly K, Carroll JA, Weis JJ, Rosa PA. Delineating the requirement for the Borrelia burgdorferi virulence factor OspC in the mammalian host. Infect Immun 2006; 74:3547-53. [PMID: 16714587 PMCID: PMC1479289 DOI: 10.1128/iai.00158-06] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously demonstrated that outer surface protein C (OspC) of Borrelia burgdorferi is essential for establishing mammalian infection. However, the role of OspC in mammalian infection is unknown. Here, we report experiments designed to distinguish between two models of OspC function in the mammalian host: (i) OspC fulfills an essential physiological role for growth and host adaptation or (ii) OspC provides a protective role for evasion of components of the innate immune response. We found that a B. burgdorferi ospC mutant, previously demonstrated to be noninfectious in both immunocompetent and SCID mice, could survive in the relatively immune-privileged environment of dialysis membrane chambers implanted within the peritoneum of a rat. The ospC mutant also adapts to the mammalian environment, as determined by the protein profiles of the chamber-cultivated spirochetes. Therefore, OspC does not appear to provide a physiological function for the survival of B. burgdorferi within the mammalian host. The second model, evasion of the innate immune system, was tested by assessing the infectivity of the ospC mutant in mice deficient for myeloid differentiation protein 88 (MyD88). Recent studies have shown that B. burgdorferi is prevented from reaching high cell numbers in the mammalian host by MyD88-dependent signaling pathways. The ospC mutant was incapable of infecting MyD88-deficient mice, suggesting that the role of OspC cannot be related solely to evasion of MyD88-mediated innate immunity. These results reiterate the importance of OspC in mammalian infection and eliminate simple models of function for this enigmatic protein.
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Affiliation(s)
- Philip E Stewart
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, NIAID, NIH, 903 South 4th St., Hamilton, MT 59840, USA.
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Caimano MJ. Cultivation of Borrelia burgdorferi in dialysis membrane chambers in rat peritonea. CURRENT PROTOCOLS IN MICROBIOLOGY 2005; Chapter 12:Unit 12C.3. [PMID: 18770553 DOI: 10.1002/9780471729259.mc12c03s00] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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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Rosa PA, Tilly K, Stewart PE. The burgeoning molecular genetics of the Lyme disease spirochaete. Nat Rev Microbiol 2005; 3:129-43. [PMID: 15685224 DOI: 10.1038/nrmicro1086] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Lyme disease is the most commonly reported vector-borne disease in North America and Europe, yet we know little about which components of the causative agent, Borrelia burgdorferi, are critical for infection or virulence. Molecular genetics has provided a powerful means by which to address these topics in other bacterial pathogens. Certain features of B. burgdorferi have hampered the development of an effective system of genetic analysis, but basic tools are now available and their application has begun to provide information about the identities and roles of key bacterial components in both the tick vector and the mammalian host. Increased genetic analysis of B. burgdorferi should advance our understanding of the infectious cycle and the pathogenesis of Lyme disease.
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Affiliation(s)
- Patricia A Rosa
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th Street, Hamilton, Montana 59840, USA.
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Anguita J, Hedrick MN, Fikrig E. Adaptation of Borrelia burgdorferi in the tick and the mammalian host. FEMS Microbiol Rev 2003; 27:493-504. [PMID: 14550942 DOI: 10.1016/s0168-6445(03)00036-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Borrelia burgdorferi, the causative agent of Lyme disease, shows a great ability to adapt to different environments, including the arthropod vector, and the mammalian host. The success of these microorganisms to survive in nature and complete their enzootic cycle depends on the regulation of genes that are essential to their survival in the different environments. This review describes the current knowledge of gene expression by B. burgdorferi in the tick and the mammalian host. The functions of the differentially regulated gene products as well as the factors that influence their expression are discussed. A thorough understanding of the changes in gene expression and the function of the differentially expressed antigens during the life cycle of the spirochete will allow a better control of this prevalent infection and the design of new, second generation vaccines to prevent infection with the spirochete.
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Affiliation(s)
- Juan Anguita
- Department of Biology, University of North Carolina at Charlotte, Charlotte, NC, USA
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Brooks CS, Hefty PS, Jolliff SE, Akins DR. Global analysis of Borrelia burgdorferi genes regulated by mammalian host-specific signals. Infect Immun 2003; 71:3371-83. [PMID: 12761121 PMCID: PMC155701 DOI: 10.1128/iai.71.6.3371-3383.2003] [Citation(s) in RCA: 211] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2003] [Revised: 02/20/2003] [Accepted: 03/18/2003] [Indexed: 11/20/2022] Open
Abstract
Lyme disease is a tick-borne infection that can lead to chronic, debilitating problems if not recognized or treated appropriately. Borrelia burgdorferi, the causative agent of Lyme disease, is maintained in nature by a complex enzootic cycle involving Ixodes ticks and mammalian hosts. Many previous studies support the notion that B. burgdorferi differentially expresses numerous genes and proteins to help it adapt to growth in the mammalian host. In this regard, several studies have utilized a dialysis membrane chamber (DMC) cultivation system to generate "mammalian host-adapted" spirochetes for the identification of genes selectively expressed during mammalian infection. Here, we have exploited the DMC cultivation system in conjunction with microarray technology to examine the global changes in gene expression that occur in the mammalian host. To identify genes regulated by only mammal-specific signals and not by temperature, borrelial microarrays were hybridized with cDNA generated either from organisms temperature shifted in vitro from 23 degrees C to 37 degrees C or from organisms cultivated by using the DMC model system. Statistical analyses of the combined data sets revealed that 125 genes were expressed at significantly different levels in the mammalian host, with almost equivalent numbers of genes being up- or down-regulated by B. burgdorferi within DMCs compared to those undergoing temperature shift. Interestingly, during DMC cultivation, the vast majority of genes identified on the plasmids were down-regulated (79%), while the differentially expressed chromosomal genes were almost entirely up-regulated (93%). Global analysis of the upstream promoter regions of differentially expressed genes revealed that several share a common motif that may be important in transcriptional regulation during mammalian infection. Among genes with known or putative functions, the cell envelope category, which includes outer membrane proteins, was found to contain the most differentially expressed genes. The combined findings have generated a subset of genes that can now be further characterized to help define their role or roles with regard to B. burgdorferi virulence and Lyme disease pathogenesis.
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Affiliation(s)
- Chad S Brooks
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City 73104, USA
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Akins DR, Bourell KW, Caimano MJ, Norgard MV, Radolf JD. A new animal model for studying Lyme disease spirochetes in a mammalian host-adapted state. J Clin Invest 1998; 101:2240-50. [PMID: 9593780 PMCID: PMC508812 DOI: 10.1172/jci2325] [Citation(s) in RCA: 199] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
There is now substantial evidence that Borrelia burgdorferi, the Lyme disease spirochete, undergoes major alterations in antigenic composition as it cycles between its arthropod and mammalian hosts. In this report, we cultivated B. burgdorferi 297 within dialysis membrane chambers implanted into the peritoneal cavities of rats to induce antigenic changes similar to those which occur during mammalian infection. Chamber-grown spirochetes, which remained fully virulent, did not express either outer surface protein A or Lp6.6, lipoproteins known to be downregulated after mammalian infection. However, they did, express p21, a well characterized outer surface protein E homologue, which is selectively expressed during infection. SDS-PAGE, two-dimensional gel electrophoresis, and immunoblot analysis revealed that chamber-grown borreliae also expressed uncharacterized proteins not expressed by in vitro-cultivated spirochetes; reactivity with sera from mice chronically infected with B. burgdorferi 297 confirmed that many of these novel proteins are selectively expressed during experimental murine infection. Finally, we used differential display RT-PCR to identify transcripts of other differentially expressed B. burgdorferi genes. One gene (2.9-7lpB) identified with this technique belongs to a family of genes located on homologous 32- and 18-kb circular plasmids. The lipoprotein encoded by 2.9-7lpB was shown to be selectively expressed by chamber-grown spirochetes and by spirochetes during experimental infection. Cultivation of B. burgdorferi in rat peritoneal implants represents a novel system for studying Lyme disease spirochetes in a mammalian host-adapted state.
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Affiliation(s)
- D R Akins
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA
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Jonsson M, Sven B. Transcriptional and translational regulation of the expression of the major outer surface proteins in Lyme disease Borrelia strains. MICROBIOLOGY (READING, ENGLAND) 1995; 141 ( Pt 6):1321-1329. [PMID: 7545508 DOI: 10.1099/13500872-141-6-1321] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The major outer surface proteins of Lyme disease spirochaetes are differentially expressed in different isolates. Borrelia afzelii strain F1 expresses none, or very low amounts, of the OspA and OspB proteins. To elucidate the mechanisms that control the expression of these abundant surface proteins the ospAB operon of B. afzelii F1 was cloned, sequenced and compared to the previously sequenced ospAB operon of B. afzelii ACAI and Borrelia burgdorferi B31. The two B. afzelii strains showed almost 100% identity at the DNA level, although Coomassie-stained gels and Western blot analyses showed significant variation in the Osp protein content. Transcriptional analysis revealed that the amount of ospAB mRNA produced in B. afzelii F1 varies more than the amount of protein, suggesting that the expression of OspA and OspB proteins is regulated at both the transcriptional and the translational level. Furthermore, the inverse relationship between the transcription of ospC and the ospAB operon could indicate coregulation of these separately encoded operons.
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MESH Headings
- Antigens, Bacterial
- Antigens, Surface/biosynthesis
- Antigens, Surface/genetics
- Bacterial Outer Membrane Proteins/biosynthesis
- Bacterial Outer Membrane Proteins/genetics
- Bacterial Vaccines
- Base Sequence
- Borrelia/classification
- Borrelia/genetics
- Borrelia/metabolism
- Borrelia burgdorferi Group/genetics
- Borrelia burgdorferi Group/metabolism
- Cloning, Molecular
- Escherichia coli
- Gene Expression Regulation, Bacterial
- Lipoproteins
- Lyme Disease/microbiology
- Molecular Sequence Data
- Operon
- Protein Biosynthesis
- RNA, Bacterial/biosynthesis
- RNA, Bacterial/genetics
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Sequence Alignment
- Sequence Homology, Nucleic Acid
- Species Specificity
- Transcription, Genetic
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Affiliation(s)
- Maria Jonsson
- Department of Microbiology, University of Umea,S-901 87 Umeå,Sweden
| | - Bergström Sven
- Department of Microbiology, University of Umea,S-901 87 Umeå,Sweden
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