1
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Kumar D, Downs LP, Embers M, Flynt AS, Karim S. Identification of microRNAs in the Lyme Disease Vector Ixodes scapularis. Int J Mol Sci 2022; 23:5565. [PMID: 35628370 PMCID: PMC9141961 DOI: 10.3390/ijms23105565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/05/2022] [Accepted: 05/10/2022] [Indexed: 02/01/2023] Open
Abstract
MicroRNAs (miRNAs) are a class of small non-coding RNAs involved in many biological processes, including the immune pathways that control bacterial, parasitic, and viral infections. Pathogens probably modify host miRNAs to facilitate successful infection, so they might be useful targets for vaccination strategies. There are few data on differentially expressed miRNAs in the black-legged tick Ixodes scapularis after infection with Borrelia burgdorferi, the causative agent of Lyme disease in the United States. Small RNA sequencing and qRT-PCR analysis were used to identify and validate differentially expressed I. scapularis salivary miRNAs. Small RNA-seq yielded 133,465,828 (≥18 nucleotides) and 163,852,135 (≥18 nucleotides) small RNA reads from Borrelia-infected and uninfected salivary glands for downstream analysis using the miRDeep2 algorithm. As such, 254 miRNAs were identified across all datasets, 25 of which were high confidence and 51 low confidence known miRNAs. Further, 23 miRNAs were differentially expressed in uninfected and infected salivary glands: 11 were upregulated and 12 were downregulated upon pathogen infection. Gene ontology and network analysis of target genes of differentially expressed miRNAs predicted roles in metabolic, cellular, development, cellular component biogenesis, and biological regulation processes. Several Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, including sphingolipid metabolism; valine, leucine and isoleucine degradation; lipid transport and metabolism; exosome biogenesis and secretion; and phosphate-containing compound metabolic processes, were predicted as targets of differentially expressed miRNAs. A qRT-PCR assay was utilized to validate the differential expression of miRNAs. This study provides new insights into the miRNAs expressed in I. scapularis salivary glands and paves the way for their functional manipulation to prevent or treat B. burgdorferi infection.
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Affiliation(s)
- Deepak Kumar
- Center for Molecular and Cellular Biosciences, University of Southern Mississippi, Hattiesburg, MS 39406, USA; (D.K.); (A.S.F.)
- School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS 39406, USA;
| | - Latoyia P. Downs
- School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS 39406, USA;
| | - Monica Embers
- Division of Immunology, Tulane National Primate Research Center, Covington, LA 70433, USA;
| | - Alex Sutton Flynt
- Center for Molecular and Cellular Biosciences, University of Southern Mississippi, Hattiesburg, MS 39406, USA; (D.K.); (A.S.F.)
- School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS 39406, USA;
| | - Shahid Karim
- Center for Molecular and Cellular Biosciences, University of Southern Mississippi, Hattiesburg, MS 39406, USA; (D.K.); (A.S.F.)
- School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS 39406, USA;
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2
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Park JM, Oliva Chávez AS, Shaw DK. Ticks: More Than Just a Pathogen Delivery Service. Front Cell Infect Microbiol 2021; 11:739419. [PMID: 34540723 PMCID: PMC8440996 DOI: 10.3389/fcimb.2021.739419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 08/11/2021] [Indexed: 12/17/2022] Open
Affiliation(s)
- Jason M Park
- Program in Vector-Borne Disease, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, United States
| | - Adela S Oliva Chávez
- Department of Entomology, Texas A&M University, College Station, TX, United States
| | - Dana K Shaw
- Program in Vector-Borne Disease, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, United States
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3
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Pal U, Kitsou C, Drecktrah D, Yaş ÖB, Fikrig E. Interactions Between Ticks and Lyme Disease Spirochetes. Curr Issues Mol Biol 2020; 42:113-144. [PMID: 33289683 DOI: 10.21775/cimb.042.113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Borrelia burgdorferi sensu lato causes Lyme borreliosis in a variety of animals and humans. These atypical bacterial pathogens are maintained in a complex enzootic life cycle that primarily involves a vertebrate host and Ixodes spp. ticks. In the Northeastern United States, I. scapularis is the main vector, while wild rodents serve as the mammalian reservoir host. As B. burgdorferi is transmitted only by I. scapularis and closely related ticks, the spirochete-tick interactions are thought to be highly specific. Various borrelial and arthropod proteins that directly or indirectly contribute to the natural cycle of B. burgdorferi infection have been identified. Discrete molecular interactions between spirochetes and tick components also have been discovered, which often play critical roles in pathogen persistence and transmission by the arthropod vector. This review will focus on the past discoveries and future challenges that are relevant to our understanding of the molecular interactions between B. burgdorferi and Ixodes ticks. This information will not only impact scientific advancements in the research of tick- transmitted infections but will also contribute to the development of novel preventive measures that interfere with the B. burgdorferi life cycle.
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Affiliation(s)
- Utpal Pal
- Department of Veterinary Medicine, University of Maryland, 8075 Greenmead Drive, College Park, MD 20742, USA
| | - Chrysoula Kitsou
- Department of Veterinary Medicine, University of Maryland, 8075 Greenmead Drive, College Park, MD 20742, USA
| | - Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Özlem Büyüktanir Yaş
- Department of Microbiology and Clinical Microbiology, Faculty of Medicine, Istinye University, Zeytinburnu, İstanbul, 34010, Turkey
| | - Erol Fikrig
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
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4
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Gupta A, Arora G, Rosen CE, Kloos Z, Cao Y, Cerny J, Sajid A, Hoornstra D, Golovchenko M, Rudenko N, Munderloh U, Hovius JW, Booth CJ, Jacobs-Wagner C, Palm NW, Ring AM, Fikrig E. A human secretome library screen reveals a role for Peptidoglycan Recognition Protein 1 in Lyme borreliosis. PLoS Pathog 2020; 16:e1009030. [PMID: 33175909 PMCID: PMC7657531 DOI: 10.1371/journal.ppat.1009030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 10/02/2020] [Indexed: 02/07/2023] Open
Abstract
Lyme disease, the most common vector-borne illness in North America, is caused by the spirochete Borrelia burgdorferi. Infection begins in the skin following a tick bite and can spread to the hearts, joints, nervous system, and other organs. Diverse host responses influence the level of B. burgdorferi infection in mice and humans. Using a systems biology approach, we examined potential molecular interactions between human extracellular and secreted proteins and B. burgdorferi. A yeast display library expressing 1031 human extracellular proteins was probed against 36 isolates of B. burgdorferi sensu lato. We found that human Peptidoglycan Recognition Protein 1 (PGLYRP1) interacted with the vast majority of B. burgdorferi isolates. In subsequent experiments, we demonstrated that recombinant PGLYRP1 interacts with purified B. burgdorferi peptidoglycan and exhibits borreliacidal activity, suggesting that vertebrate hosts may use PGLYRP1 to identify B. burgdorferi. We examined B. burgdorferi infection in mice lacking PGLYRP1 and observed an increased spirochete burden in the heart and joints, along with splenomegaly. Mice lacking PGLYRP1 also showed signs of immune dysregulation, including lower serum IgG levels and higher levels of IFNγ, CXCL9, and CXCL10.Taken together, our findings suggest that PGLYRP1 plays a role in the host’s response to B. burgdorferi and further demonstrate the utility of expansive yeast display screening in capturing biologically relevant interactions between spirochetes and their hosts. Lyme disease is the most common vector-borne illness in North America and is caused by the spirochete Borrelia burgdorferi. The disease starts with a tick bite that leads to a skin rash and inflammation in other organs of the body, such as hearts and joints. B. burgdorferi uses many strategies to evade detection and persist in the human host. It is important to have efficient methods to be able to identify the various components of the immune system that interact with B. burgdorferi to better understand the disease process, but few currently exist. In this study, we used a novel yeast display screening assay of over 1,000 human immune proteins probed against several isolates of Borrelia to uncover biologically relevant interactions for the Lyme disease pathogen. We identified Peptidoglycan Recognition Protein 1 (PGLYRP1), an innate immune protein important in defense against bacteria, as a major candidate from this screen. We validated the interaction of PGLYRP1 with Borrelia and were able to use PGLYRP1-deficient mice as a model to understand the role of this protein in Lyme disease pathogenesis. Our study demonstrates the potential implications of yeast screens in uncovering important host-pathogen interactions.
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Affiliation(s)
- Akash Gupta
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Gunjan Arora
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Connor E. Rosen
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Zachary Kloos
- Microbiology Program, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Yongguo Cao
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Clinical Veterinary Medicine, and Key Laboratory for Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Jiri Cerny
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Faculty of Tropical AgriSciences, Czech University of Life Sciences in Prague, Prague, Czech Republic
| | - Andaleeb Sajid
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Dieuwertje Hoornstra
- Amsterdam UMC, University of Amsterdam, Center for Experimental and Molecular Medicine, Amsterdam Infection and Immunity, Amsterdam, Netherlands
| | - Maryna Golovchenko
- Biology Centre, Institute of Parasitology Czech Academy of Sciences, Buweiss, Czech Republic
| | - Natalie Rudenko
- Biology Centre, Institute of Parasitology Czech Academy of Sciences, Buweiss, Czech Republic
| | - Ulrike Munderloh
- Department of Entomology, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Joppe W. Hovius
- Amsterdam UMC, University of Amsterdam, Center for Experimental and Molecular Medicine, Amsterdam Infection and Immunity, Amsterdam, Netherlands
| | - Carmen J. Booth
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Christine Jacobs-Wagner
- Department of Biology, Stanford University, Stanford, California, United States of America
- ChEM-H Institute, Stanford University, Stanford, California, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Noah W. Palm
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
- * E-mail: (NWP); (AMR); (EF)
| | - Aaron M. Ring
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
- * E-mail: (NWP); (AMR); (EF)
| | - Erol Fikrig
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
- * E-mail: (NWP); (AMR); (EF)
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5
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Rudenko N, Golovchenko M, Kybicova K, Vancova M. Metamorphoses of Lyme disease spirochetes: phenomenon of Borrelia persisters. Parasit Vectors 2019; 12:237. [PMID: 31097026 PMCID: PMC6521364 DOI: 10.1186/s13071-019-3495-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/09/2019] [Indexed: 12/22/2022] Open
Abstract
The survival of spirochetes from the Borrelia burgdorferi (sensu lato) complex in a hostile environment is achieved by the regulation of differential gene expression in response to changes in temperature, salts, nutrient content, acidity fluctuation, multiple host or vector dependent factors, and leads to the formation of dormant subpopulations of cells. From the other side, alterations in the level of gene expression in response to antibiotic pressure leads to the establishment of a persisters subpopulation. Both subpopulations represent the cells in different physiological states. "Dormancy" and "persistence" do share some similarities, e.g. both represent cells with low metabolic activity that can exist for extended periods without replication, both constitute populations with different gene expression profiles and both differ significantly from replicating forms of spirochetes. Persisters are elusive, present in low numbers, morphologically heterogeneous, multi-drug-tolerant cells that can change with the environment. The definition of "persisters" substituted the originally-used term "survivors", referring to the small bacterial population of Staphylococcus that survived killing by penicillin. The phenomenon of persisters is present in almost all bacterial species; however, the reasons why Borrelia persisters form are poorly understood. Persisters can adopt varying sizes and shapes, changing from well-known forms to altered morphologies. They are capable of forming round bodies, L-form bacteria, microcolonies or biofilms-like aggregates, which remarkably change the response of Borrelia to hostile environments. Persisters remain viable despite aggressive antibiotic challenge and are able to reversibly convert into motile forms in a favorable growth environment. Persisters are present in significant numbers in biofilms, which has led to the explanation of biofilm tolerance to antibiotics. Considering that biofilms are associated with numerous chronic diseases through their resilient presence in the human body, it is not surprising that interest in persisting cells has consequently accelerated. Certain diseases caused by pathogenic bacteria (e.g. tuberculosis, syphilis or leprosy) are commonly chronic in nature and often recur despite antibiotic treatment. Three decades of basic and clinical research have not yet provided a definite answer to the question: is there a connection between persisting spirochetes and recurrence of Lyme disease in patients?
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Affiliation(s)
- Natalie Rudenko
- Biology Centre CAS, Institute of Parasitology, Branisovska 31, 37005 Ceske Budejovice, Czech Republic
| | - Maryna Golovchenko
- Biology Centre CAS, Institute of Parasitology, Branisovska 31, 37005 Ceske Budejovice, Czech Republic
| | - Katerina Kybicova
- National Institute of Public Health, Srobarova 48, 100 42 Prague 10, Czech Republic
| | - Marie Vancova
- Biology Centre CAS, Institute of Parasitology, Branisovska 31, 37005 Ceske Budejovice, Czech Republic
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6
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Vechtova P, Sterbova J, Sterba J, Vancova M, Rego ROM, Selinger M, Strnad M, Golovchenko M, Rudenko N, Grubhoffer L. A bite so sweet: the glycobiology interface of tick-host-pathogen interactions. Parasit Vectors 2018; 11:594. [PMID: 30428923 PMCID: PMC6236881 DOI: 10.1186/s13071-018-3062-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 08/14/2018] [Indexed: 11/10/2022] Open
Abstract
Vector-borne diseases constitute 17% of all infectious diseases in the world; among the blood-feeding arthropods, ticks transmit the highest number of pathogens. Understanding the interactions between the tick vector, the mammalian host and the pathogens circulating between them is the basis for the successful development of vaccines against ticks or the tick-transmitted pathogens as well as for the development of specific treatments against tick-borne infections. A lot of effort has been put into transcriptomic and proteomic analyses; however, the protein-carbohydrate interactions and the overall glycobiology of ticks and tick-borne pathogens has not been given the importance or priority deserved. Novel (bio)analytical techniques and their availability have immensely increased the possibilities in glycobiology research and thus novel information in the glycobiology of ticks and tick-borne pathogens is being generated at a faster pace each year. This review brings a comprehensive summary of the knowledge on both the glycosylated proteins and the glycan-binding proteins of the ticks as well as the tick-transmitted pathogens, with emphasis on the interactions allowing the infection of both the ticks and the hosts by various bacteria and tick-borne encephalitis virus.
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Affiliation(s)
- Pavlina Vechtova
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, CZ-37005, České Budějovice, Czech Republic. .,Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005, České Budějovice, Czech Republic.
| | - Jarmila Sterbova
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, CZ-37005, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005, České Budějovice, Czech Republic
| | - Jan Sterba
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, CZ-37005, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005, České Budějovice, Czech Republic
| | - Marie Vancova
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, CZ-37005, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005, České Budějovice, Czech Republic
| | - Ryan O M Rego
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, CZ-37005, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005, České Budějovice, Czech Republic
| | - Martin Selinger
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, CZ-37005, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005, České Budějovice, Czech Republic
| | - Martin Strnad
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, CZ-37005, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005, České Budějovice, Czech Republic
| | - Maryna Golovchenko
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, CZ-37005, České Budějovice, Czech Republic
| | - Nataliia Rudenko
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, CZ-37005, České Budějovice, Czech Republic
| | - Libor Grubhoffer
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, CZ-37005, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005, České Budějovice, Czech Republic
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7
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Borrelia burgdorferi surface protein Lmp1 facilitates pathogen dissemination through ticks as studied by an artificial membrane feeding system. Sci Rep 2018; 8:1910. [PMID: 29382879 PMCID: PMC5790009 DOI: 10.1038/s41598-018-20208-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 01/15/2018] [Indexed: 12/17/2022] Open
Abstract
In its natural infection cycle, the pathogen of Lyme borreliosis transits between a tick vector and a mammalian host. As relatively a minor fraction of spirochetes transits between the host and the vector precluding their reliable detection at early infection, artificial membrane feeders emerged as useful tools to study roles of spirochete proteins in pathogen entry, persistence, and exit through ticks. Here we report the development of a modified membrane feeder to study the role of a Borrelia burgdorferi surface protein called Lmp1 in spirochete transitions between the murine host and ticks. We show that our membrane feeder supports the blood meal engorgement process where ticks can acquire spirochetes from the feeder containing extremely low levels of pathogens (102 cells/ml of blood). Our data revealed that in comparison to wild-type spirochetes, lmp1 deletion mutants are significantly impaired for acquisition in naïve ticks as well as transmission from infected ticks. Taking together, our data suggest that Lmp1 plays an essential role in spirochete transitions between hosts and the vector. These studies also underscore the usefulness of artificial membrane feeding system as a valuable tool to study the role of B. burgdorferi gene-products in pathogen persistence in and passage through vector ticks.
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8
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Glatz M, Means T, Haas J, Steere AC, Müllegger RR. Characterization of the early local immune response to Ixodes ricinus tick bites in human skin. Exp Dermatol 2017; 26:263-269. [PMID: 27623398 DOI: 10.1111/exd.13207] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2016] [Indexed: 12/30/2022]
Abstract
Little is known about the immunomodulation by tick saliva during a natural tick bite in human skin, the site of the tick-host interaction. We examined the expression of chemokines, cytokines and leucocyte markers on the mRNA levels and histopathologic changes in human skin biopsies of tick bites (n=37) compared to unaffected skin (n=9). Early tick-bite skin lesions (<24 hours of tick attachment) were characterized by a predominance of macrophages and dendritic cells, elevated mRNA levels of macrophage chemoattractants (CCL2, CCL3, CCL4) and neutrophil chemoattractants (CXCL1, CXCL8), of the pro-inflammatory cytokine, IL-1β, and the anti-inflammatory cytokine, IL-5. In contrast, the numbers of lymphocytes and mRNA levels of lymphocyte cell markers (CD4, CD8, CD19), lymphocyte chemoattractants (CXCL9, CXCL10, CXCL11, CXCL13, CCL1, CCL22), dendritic cell chemoattractants (CCL20), and other pro- (IL-6, IL-12p40, IFN-γ, TNF-α) and anti-inflammatory cytokines (IL-4, IL-10, TGF-β) did not differ from normal skin. With longer tick attachment (>24 hours), the numbers of innate immune cells and mediators (not significantly) declined, whereas the numbers of lymphocytes (not significantly) increased. Natural tick bites by Ixodes ricinus ticks initially elicit a strong local innate immune response in human skin. Beyond 24 hours of tick attachment, this response usually becomes less, perhaps because of immunomodulation by tick saliva.
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Affiliation(s)
- Martin Glatz
- Division of Rheumatology Allergy and Immunology, Center for Immunology and Inflammatory Diseases, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA.,Allergy Unit, Department of Dermatology, University and University Hospital of Zurich, Zurich, Switzerland
| | - Terry Means
- Division of Rheumatology Allergy and Immunology, Center for Immunology and Inflammatory Diseases, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
| | - Josef Haas
- Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria
| | - Allen C Steere
- Division of Rheumatology Allergy and Immunology, Center for Immunology and Inflammatory Diseases, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
| | - Robert R Müllegger
- Department of Dermatology, State Hospital Wiener Neustadt, Wiener Neustadt, Austria.,Department of Dermatology, Medical University of Graz, Graz, Austria
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9
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Spirochetal motility and chemotaxis in the natural enzootic cycle and development of Lyme disease. Curr Opin Microbiol 2015; 28:106-13. [PMID: 26519910 DOI: 10.1016/j.mib.2015.09.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 09/07/2015] [Indexed: 11/21/2022]
Abstract
Two-thirds of all bacterial genomes sequenced to-date possess an organelle for locomotion, referred to as flagella, periplasmic flagella or type IV pili. These genomes may also contain a chemotaxis-signaling system which governs flagellar rotation, thus leading a coordinated function for motility. Motility and chemotaxis are often crucial for infection or disease process caused by pathogenic bacteria. Although motility-associated genes are well-characterized in some organisms, the highly orchestrated synthesis, regulation, and assembly of periplasmic flagella in spirochetes are just being delineated. Recent advances were fostered by development of unique genetic manipulations in spirochetes coupled with cutting-edge imaging techniques. These contemporary advances in understanding the role of spirochetal motility and chemotaxis in host persistence and disease development are highlighted in this review.
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10
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Absence of sodA Increases the Levels of Oxidation of Key Metabolic Determinants of Borrelia burgdorferi. PLoS One 2015; 10:e0136707. [PMID: 26322513 PMCID: PMC4556403 DOI: 10.1371/journal.pone.0136707] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 08/07/2015] [Indexed: 11/20/2022] Open
Abstract
Borrelia burgdorferi, the causative agent of Lyme disease, alters its gene expression in response to environmental signals unique to its tick vector or vertebrate hosts. B. burgdorferi carries one superoxide dismutase gene (sodA) capable of controlling intracellular superoxide levels. Previously, sodA was shown to be essential for infection of B. burgdorferi in the C3H/HeN model of Lyme disease. We employed two-dimensional electrophoresis (2-DE) and immunoblot analysis with antibodies specific to carbonylated proteins to identify targets that were differentially oxidized in the soluble fractions of the sodA mutant compared to its isogenic parental control strain following treatment with an endogenous superoxide generator, methyl viologen (MV, paraquat). HPLC-ESI-MS/MS analysis of oxidized proteins revealed that several proteins of the glycolytic pathway (BB0057, BB0020, BB0348) exhibited increased carbonylation in the sodA mutant treated with MV. Levels of ATP and NAD/NADH were reduced in the sodA mutant compared with the parental strain following treatment with MV and could be attributed to increased levels of oxidation of proteins of the glycolytic pathway. In addition, a chaperone, HtpG (BB0560), and outer surface protein A (OspA, BBA15) were also observed to be oxidized in the sodA mutant. Immunoblot analysis revealed reduced levels of Outer surface protein C (OspC), Decorin binding protein A (DbpA), fibronectin binding protein (BBK32), RpoS and BosR in the sodA mutant compared to the control strains. Viable sodA mutant spirochetes could not be recovered from both gp91/phox-⁄- and iNOS deficient mice while borrelial DNA was detected in multiple tissues samples from infected mice at significantly lower levels compared to the parental strain. Taken together, these observations indicate that the increased oxidation of select borrelial determinants and reduced levels of critical pathogenesis-associated lipoproteins contribute to the in vivo deficit of the sodA mutant in the mouse model of Lyme disease. This study, utilizing the sodA mutant, has provided insights into adaptive capabilities critical for survival of B. burgdorferi in its hosts.
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11
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Yang X, Lin YP, Heselpoth RD, Buyuktanir O, Qin J, Kung F, Nelson DC, Leong JM, Pal U. Middle region of the Borrelia burgdorferi surface-located protein 1 (Lmp1) interacts with host chondroitin-6-sulfate and independently facilitates infection. Cell Microbiol 2015; 18:97-110. [PMID: 26247174 DOI: 10.1111/cmi.12487] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Revised: 06/23/2015] [Accepted: 07/10/2015] [Indexed: 11/29/2022]
Abstract
Borrelia burgdorferi surface-located membrane protein 1, also known as Lmp1, has been shown to play critical roles in pathogen evasion of host-acquired immune defences, thereby facilitating persistent infection. Lmp1 possesses three regions representing potentially discrete domains: Lmp1N, Lmp1M and Lmp1C. Because of its insignificant homology to known proteins, how Lmp1 or its specific regions contribute to microbial biology and infection remains enigmatic. Here, we show that distinct from Lmp1N and Lmp1C, Lmp1M is composed of at least 70% alpha helices and completely lacks recognizable beta sheets. The region binds to host glycosaminoglycan chondroitin-6-sulfate molecules and facilitates mammalian cell attachment, suggesting an adhesin function of Lmp1M. Phenotypic analysis of the Lmp1-deficient mutant engineered to produce Lmp1M on the microbial surface suggests that Lmp1M can independently support B. burgdorferi infectivity in murine hosts. Further exploration of functions of Lmp1 distinct regions will shed new light on the intriguing biology and infectivity of spirochetes and help develop novel interventions to combat Lyme disease.
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Affiliation(s)
- Xiuli Yang
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, 20742, USA
| | - Yi-Pin Lin
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA, 02111, USA
| | - Ryan D Heselpoth
- Institute for Bioscience and Biotechnology Research, University of Maryland, 9600 Gudelsky Drive, Rockville, MD, 20850, USA
| | - Ozlem Buyuktanir
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, 20742, USA
| | - Jinhong Qin
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, 20742, USA
| | - Faith Kung
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, 20742, USA
| | - Daniel C Nelson
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, 20742, USA.,Institute for Bioscience and Biotechnology Research, University of Maryland, 9600 Gudelsky Drive, Rockville, MD, 20850, USA
| | - John M Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA, 02111, USA
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, 20742, USA
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12
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Motor rotation is essential for the formation of the periplasmic flagellar ribbon, cellular morphology, and Borrelia burgdorferi persistence within Ixodes scapularis tick and murine hosts. Infect Immun 2015; 83:1765-77. [PMID: 25690096 DOI: 10.1128/iai.03097-14] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 02/05/2015] [Indexed: 12/13/2022] Open
Abstract
Borrelia burgdorferi must migrate within and between its arthropod and mammalian hosts in order to complete its natural enzootic cycle. During tick feeding, the spirochete transmits from the tick to the host dermis, eventually colonizing and persisting within multiple, distant tissues. This dissemination modality suggests that flagellar motor rotation and, by extension, motility are crucial for infection. We recently reported that a nonmotile flaB mutant that lacks periplasmic flagella is rod shaped and unable to infect mice by needle or tick bite. However, those studies could not differentiate whether motor rotation or merely the possession of the periplasmic flagella was crucial for cellular morphology and host persistence. Here, we constructed and characterized a motB mutant that is nonmotile but retains its periplasmic flagella. Even though ΔmotB bacteria assembled flagella, part of the mutant cell is rod shaped. Cryoelectron tomography revealed that the flagellar ribbons are distorted in the mutant cells, indicating that motor rotation is essential for spirochetal flat-wave morphology. The ΔmotB cells are unable to infect mice, survive in the vector, or migrate out of the tick. Coinfection studies determined that the presence of these nonmotile ΔmotB cells has no effect on the clearance of wild-type spirochetes during murine infection and vice versa. Together, our data demonstrate that while flagellar motor rotation is necessary for spirochetal morphology and motility, the periplasmic flagella display no additional properties related to immune clearance and persistence within relevant hosts.
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13
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Vaumourin E, Gasqui P, Buffet JP, Chapuis JL, Pisanu B, Ferquel E, Vayssier-Taussat M, Vourc'h G. A probabilistic model in cross-sectional studies for identifying interactions between two persistent vector-borne pathogens in reservoir populations. PLoS One 2013; 8:e66167. [PMID: 23840418 PMCID: PMC3688727 DOI: 10.1371/journal.pone.0066167] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 05/03/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND In natural populations, individuals are infected more often by several pathogens than by just one. In such a context, pathogens can interact. This interaction could modify the probability of infection by subsequent pathogens. Identifying when pathogen associations correspond to biological interactions is a challenge in cross-sectional studies where the sequence of infection cannot be demonstrated. METHODOLOGY/PRINCIPAL FINDINGS Here we modelled the probability of an individual being infected by one and then another pathogen, using a probabilistic model and maximum likelihood statistics. Our model was developed to apply to cross-sectional data, vector-borne and persistent pathogens, and to take into account confounding factors. Our modelling approach was more powerful than the commonly used Chi-square test of independence. Our model was applied to detect potential interaction between Borrelia afzelii and Bartonella spp. that infected a bank vole population at 11% and 57% respectively. No interaction was identified. CONCLUSIONS/SIGNIFICANCE The modelling approach we proposed is powerful and can identify the direction of potential interaction. Such an approach can be adapted to other types of pathogens, such as non-persistents. The model can be used to identify when co-occurrence patterns correspond to pathogen interactions, which will contribute to understanding how organism communities are assembled and structured. In the long term, the model's capacity to better identify pathogen interactions will improve understanding of infectious risk.
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Affiliation(s)
- Elise Vaumourin
- INRA, UR346 Epidémiologie Animale, Saint Genès Champanelle, France.
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14
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Kung F, Anguita J, Pal U. Borrelia burgdorferi and tick proteins supporting pathogen persistence in the vector. Future Microbiol 2013; 8:41-56. [PMID: 23252492 DOI: 10.2217/fmb.12.121] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Borrelia burgdorferi, a pathogen transmitted by Ixodes ticks, is responsible for a prevalent illness known as Lyme disease, and a vaccine for human use is unavailable. Recently, genome sequences of several B. burgdorferi strains and Ixodes scapularis ticks have been determined. In addition, remarkable progress has been made in developing molecular genetic tools to study the pathogen and vector, including their intricate relationship. These developments are helping unravel the mechanisms by which Lyme disease pathogens survive in a complex enzootic infection cycle. Notable discoveries have already contributed to understanding the spirochete gene regulation accounting for the temporal and spatial expression of B. burgdorferi genes during distinct phases of the lifecycle. A number of pathogen and vector gene products have also been identified that contribute to microbial virulence and/or persistence. These research directions will enrich our knowledge of vector-borne infections and contribute towards the development of preventative strategies against Lyme disease.
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Affiliation(s)
- Faith Kung
- Department of Veterinary Medicine & Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA
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15
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BB0172, a Borrelia burgdorferi outer membrane protein that binds integrin α3β1. J Bacteriol 2013; 195:3320-30. [PMID: 23687274 DOI: 10.1128/jb.00187-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Lyme disease is a multisystemic disorder caused by Borrelia burgdorferi infection. Upon infection, some B. burgdorferi genes are upregulated, including members of the microbial surface components recognizing adhesive matrix molecule (MSCRAMM) protein family, which facilitate B. burgdorferi adherence to extracellular matrix components of the host. Comparative genome analysis has revealed a new family of B. burgdorferi proteins containing the von Willebrand factor A (vWFA) domain. In the present study, we characterized the expression and membrane association of the vWFA domain-containing protein BB0172 by using in vitro transcription/translation systems in the presence of microsomal membranes and with detergent phase separation assays. Our results showed evidence of BB0172 localization in the outer membrane, the orientation of the vWFA domain to the extracellular environment, and its function as a metal ion-dependent integrin-binding protein. This is the first report of a borrelial adhesin with a metal ion-dependent adhesion site (MIDAS) motif that is similar to those observed in eukaryotic integrins and has a similar function.
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16
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Miller CL, Karna SLR, Seshu J. Borrelia host adaptation Regulator (BadR) regulates rpoS to modulate host adaptation and virulence factors in Borrelia burgdorferi. Mol Microbiol 2013; 88:105-24. [PMID: 23387366 DOI: 10.1111/mmi.12171] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2013] [Indexed: 11/27/2022]
Abstract
The RpoS transcription factor of Borrelia burgdorferi is a 'gatekeeper' because it activates genes required for spirochaetes to transition from tick to vertebrate hosts. However, it remains unknown how RpoS becomes repressed to allow the spirochaetes to transition back from the vertebrate host to the tick vector. Here we show that a putative carbohydrate-responsive regulatory protein, designated BadR (Borrelia host adaptation Regulator), is a transcriptional repressor of rpoS. BadR levels are elevated in B. burgdorferi cultures grown under in vitro conditions mimicking unfed-ticks and badR-deficient strains are defective for growth under these same conditions. Microarray and immunoblot analyses of badR-deficient strains showed upregulation of rpoS and other factors important for virulence in vertebrate hosts, as well as downregulation of putative tick-specific determinants (e.g. linear plasmid 28-4 genes). DNA-binding assays revealed BadR binds to upstream regions of rpoS. Site-directed mutations in BadR and the presence of phosphorylated sugars affected BadR's binding to the rpoS promoters. badR-deficient B. burgdorferi were unable to colonize mice. Several putative tick-specific targets have been identified. Our study identified a novel regulator, BadR, and provides a link between nutritional environmental cues utilized by spirochaetes to adaptation to disparate conditions found in the tick and vertebrate hosts.
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Affiliation(s)
- Christine L Miller
- South Texas Center for Emerging Infectious Diseases, Center for Excellence in Infection Genomics and Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, USA
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17
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Patramool S, Choumet V, Surasombatpattana P, Sabatier L, Thomas F, Thongrungkiat S, Rabilloud T, Boulanger N, Biron DG, Missé D. Update on the proteomics of major arthropod vectors of human and animal pathogens. Proteomics 2012; 12:3510-23. [DOI: 10.1002/pmic.201200300] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 09/13/2012] [Accepted: 10/02/2012] [Indexed: 12/12/2022]
Affiliation(s)
| | - Valérie Choumet
- Unité de Génétique Moléculaire des Bunyavirus; Institut Pasteur; Paris; France
| | | | - Laurence Sabatier
- Département des Sciences Analytiques Institut Pluridisciplinaire Hubert Curien; Strasbourg; France
| | - Frédéric Thomas
- Laboratoire MIVEGEC; UMR CNRS 5290/IRD 224/UM1; Montpellier; France
| | - Supatra Thongrungkiat
- Department of Medical Entomology; Faculty of Tropical Medicine; Mahidol University; Bangkok; Thailand
| | - Thierry Rabilloud
- CNRS UMR 5249; Chemistry and Biology of Metals; CEA; Grenoble; France
| | - Nathalie Boulanger
- EA4438 Physiopathologie et médecine translationnelle; Faculté de Pharmacie; Illkirch; France
| | - David G. Biron
- CNRS UMR 6023; Laboratoire Microorganismes: Génome et Environnement; Aubière; France
| | - Dorothée Missé
- Laboratoire MIVEGEC; UMR CNRS 5290/IRD 224/UM1; Montpellier; France
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18
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Ullmann AJ, Dolan MC, Sackal CA, Fikrig E, Piesman J, Zeidner NS. Immunization with adenoviral-vectored tick salivary gland proteins (SALPs) in a murine model of Lyme borreliosis. Ticks Tick Borne Dis 2012; 4:160-3. [PMID: 23141105 DOI: 10.1016/j.ttbdis.2012.08.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 08/14/2012] [Accepted: 08/21/2012] [Indexed: 10/27/2022]
Abstract
Prior exposure of vertebrate hosts to tick salivary proteins can induce specific immunity to tick infestation, as well as affording protection against tick-transmitted Borrelia burgdorferi infection in the mammalian host. Vaccination using an adenovirus expression system to deliver 4 tick salivary proteins (Ad-Salps) derived from Ixodes scapularis, Salp15, Salp25A, Salp25D, and Isac, was explored. Results indicate that vaccination with tick salivary proteins in an adenoviral vector can be used to modulate a Th1 response in the host and partially control spirochete load in immunized mice after infected tick challenge.
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Affiliation(s)
- A J Ullmann
- Centers for Disease Control and Prevention, Division of Vector-Borne Diseases, Bacterial Disease Branch, 3156 Rampart Road, Fort Collins, CO 80521, USA.
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19
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Microarray analyses of inflammation response of human dermal fibroblasts to different strains of Borrelia burgdorferi sensu stricto. PLoS One 2012; 7:e40046. [PMID: 22768217 PMCID: PMC3386942 DOI: 10.1371/journal.pone.0040046] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 05/31/2012] [Indexed: 11/19/2022] Open
Abstract
In Lyme borreliosis, the skin is the key site of bacterial inoculation by the infected tick, and of cutaneous manifestations, erythema migrans and acrodermatitis chronica atrophicans. We explored the role of fibroblasts, the resident cells of the dermis, in the development of the disease. Using microarray experiments, we compared the inflammation of fibroblasts induced by three strains of Borrelia burgdorferi sensu stricto isolated from different environments and stages of Lyme disease: N40 (tick), Pbre (erythema migrans) and 1408 (acrodermatitis chronica atrophicans). The three strains exhibited a similar profile of inflammation with strong induction of chemokines (CXCL1 and IL-8) and IL-6 cytokine mainly involved in the chemoattraction of immune cells. Molecules such as TNF-alpha and NF-κB factors, metalloproteinases (MMP-1, -3 and -12) and superoxide dismutase (SOD2), also described in inflammatory and cellular events, were up-regulated. In addition, we showed that tick salivary gland extracts induce a cytotoxic effect on fibroblasts and that OspC, essential in the transmission of Borrelia to the vertebrate host, was not responsible for the secretion of inflammatory molecules by fibroblasts. Tick saliva components could facilitate the early transmission of the disease to the site of injury creating a feeding pit. Later in the development of the disease, Borrelia would intensively multiply in the skin and further disseminate to distant organs.
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20
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Yang X, Promnares K, Qin J, He M, Shroder DY, Kariu T, Wang Y, Pal U. Characterization of multiprotein complexes of the Borrelia burgdorferi outer membrane vesicles. J Proteome Res 2011; 10:4556-66. [PMID: 21875077 DOI: 10.1021/pr200395b] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Among bacterial cell envelopes, the Borrelia burgdorferi outer membrane (OM) is structurally unique in that the identities of many protein complexes remain unknown; however, their characterization is the first step toward our understanding of membrane protein interactions and potential functions. Here, we used two-dimensional blue native/SDS-PAGE/mass spectrometric analysis for a global characterization of protein-protein interactions as well as to identify protein complexes in OM vesicles isolated from multiple infectious sensu stricto isolates of B. burgdorferi. Although we uncovered the existence of at least 10 distinct OM complexes harboring several unique subunits, the complexome is dominated by the frequent occurrence of a limited diversity of membrane proteins, most notably P13, outer surface protein (Osp) A, -B, -C, and -D and Lp6.6. The occurrence of these complexes and specificity of subunit interaction were further supported by independent two-dimensional immunoblotting and coimmunoprecipitation assays as well as by mutagenesis studies, where targeted depletion of a subunit member (P66) selectively abolished a specific complex. Although a comparable profile of the OM complexome was detected in two major infectious isolates, such as B31 and 297, certain complexes are likely to occur in an isolate-specific manner. Further assessment of protein complexes in multiple Osp-deficient isolates showed loss of several protein complexes but revealed the existence of additional complex/subunits that are undetectable in wild-type cells. Together, these observations uncovered borrelial antigens involved in membrane protein interactions. The study also suggests that the assembly process of OM complexes is specific and that the core or stabilizing subunits vary between complexes. Further characterization of these protein complexes including elucidation of their biological significance may shed new light on the mechanism of pathogen persistence and the development of preventative measures against the infection.
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Affiliation(s)
- Xiuli Yang
- Department of Veterinary Medicine, University of Maryland , College Park and Virginia-Maryland Regional College of Veterinary Medicine, United States
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21
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Oligopeptide permease A5 modulates vertebrate host-specific adaptation of Borrelia burgdorferi. Infect Immun 2011; 79:3407-20. [PMID: 21628523 DOI: 10.1128/iai.05234-11] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Borrelia burgdorferi, the agent of Lyme disease, undergoes rapid adaptive gene expression in response to signals unique to its arthropod vector or vertebrate hosts. Among the upregulated genes under vertebrate host conditions is one of the five annotated homologs of oligopeptide permease A (OppA5, BBA34). A mutant lacking oppA5 was constructed in an lp25-deficient isolate of B. burgdorferi strain B31, and the minimal regions of infectivity were restored via a shuttle vector pBBE22 with or without an intact copy of bba34. Immunoblot analysis of the bba34 mutant revealed a reduction in the levels of RpoS, BosR, and CsrA(Bb) with a concomitant reduction in the levels of OspC, DbpA, BBK32, and BBA64. There were no changes in the levels of OspA, NapA, P66, and three other OppA orthologs. Quantitative transcriptional analysis correlated with the changes in the protein levels. However, the bba34 mutant displayed comparable infectivities in the C3H/HeN mice and the wild-type strain, despite the reduction in several pathogenesis-related proteins. Supplementation of the growth medium with increased levels of select components, notably sodium acetate and sodium bicarbonate, restored the levels of several proteins in the bba34 mutant to wild-type levels. We speculate that the transport of acetate appears to contribute to the accumulation of key metabolites, like acetyl phosphate, that facilitate the adaptation of B. burgdorferi to the vertebrate host by the activation of the Rrp2-RpoN-RpoS pathway. These studies underscore the importance of solute transport to host-specific adaptation of B. burgdorferi.
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Abstract
Lyme disease is the most common tick-borne disease in the United States and Europe. Increased awareness of the clinical manifestations of the disease is needed to improve detection and treatment. In the acute and late stages, Lyme disease may be difficult to distinguish from other disease processes. The epidemiology and pathophysiology of Lyme disease are directly related to the Borrelia burgdorferi spirochete and its effects on the integumentary, neurologic, cardiac, and musculoskeletal systems. Lyme arthritis is a common clinical manifestation of Lyme disease and should be considered in the evaluation of patients with monoarticular or pauciarticular joint complaints in a geographic area in which Lyme disease is endemic. Management of Lyme arthritis involves eradication of the spirochete with antibiotics. Generally, the prognosis is excellent. Arthroscopic synovectomy is reserved for refractory cases that do not respond to antibiotics.
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James FM, Engiles JB, Beech J. Meningitis, cranial neuritis, and radiculoneuritis associated with Borrelia burgdorferi infection in a horse. J Am Vet Med Assoc 2010; 237:1180-5. [PMID: 21073390 DOI: 10.2460/javma.237.10.1180] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
CASE DESCRIPTION A 12-year-old Thoroughbred was examined because of signs of depression, neck stiffness, and poor performance. CLINICAL FINDINGS Physical examination revealed that the horse was dull, appeared depressed, was reluctant to raise its neck and head above a horizontal plane, and had a temperature of 38.5°C (101.3°F). No radiographic or scintigraphic abnormalities of the neck were found; however, high plasma fibrinogen concentration and relative lymphopenia were identified and the horse was seropositive for antibodies against Borrelia burgdorferi. Analysis of CSF revealed neutrophilic inflammation, and results of a PCR assay of CSF for B burgdorferi DNA were positive. Immunologic testing revealed severe B-cell lymphopenia and a low serum IgM concentration consistent with common variable immunodeficiency. TREATMENT AND OUTCOME The horse responded well to do×ycycline treatment (10 mg/kg [4.5 mg/lb], PO, q 12 h for 60 days) and returned to normal exercise. However, 60 days after treatment was discontinued, the horse again developed a stiff neck and rapidly progressive neurologic deficits, including severe ataxia and vestibular deficits. The horse's condition deteriorated rapidly despite IV oxytetracycline treatment, and the horse was euthanatized. Postmortem examination revealed leptomeningitis, lymphohistiocytic leptomeningeal vasculitis, cranial neuritis, and peripheral radiculoneuritis with Wallerian degeneration; findings were consistent with a diagnosis of neuroborreliosis. CLINICAL RELEVANCE Nervous system infection with B burgdorferi should be considered in horses with evidence of meningitis and high or equivocal serum anti-B burgdorferi antibody titers. Evaluation of immune function is recommended in adult horses evaluated because of primary bacterial meningitis.
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Affiliation(s)
- Frances M James
- Department of Clinical Studies, University of Pennsylvania, PA 19348, USA.
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Abstract
Tick saliva has potent immunomodulatory properties. In arthropod-borne diseases, this effect is largely used by microorganisms to increase their pathogenicity and to evade host immune responses. We show that in Lyme borreliosis, tick salivary gland extract and a tick saliva protein, Salp15, inhibit in vitro keratinocyte inflammation induced by Borrelia burgdorferi sensu stricto or by the major outer surface lipoprotein of Borrelia, OspC. Chemokines (interleukin-8 [IL-8] and monocyte chemoattractant protein 1 [MCP-1]) and several antimicrobial peptides (defensins, cathelicidin, psoriasin, and RNase 7) were downregulated. Interestingly, antimicrobial peptides (AMPs) transiently inhibited bacterial motility but did not kill the organisms when tested in vitro. We conclude that tick saliva affects the chemotactic properties of chemokines and AMPs on immune cells and has an antialarmin effect on human primary keratinocytes. Alarmins are mediators that mobilize and activate antigen-presenting cells. Inhibition of cutaneous innate immunity and of the migration of immune cells to the site of the tick bite ensures a favorable environment for Borrelia. The bacterium can then multiply locally and, subsequently, disseminate to the target organs, including joints, heart, and the central nervous system.
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25
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Dai J, Wang P, Adusumilli S, Booth CJ, Narasimhan S, Anguita J, Fikrig E. Antibodies against a tick protein, Salp15, protect mice from the Lyme disease agent. Cell Host Microbe 2010; 6:482-92. [PMID: 19917502 DOI: 10.1016/j.chom.2009.10.006] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Revised: 08/31/2009] [Accepted: 10/09/2009] [Indexed: 11/24/2022]
Abstract
Traditionally, vaccines directly target a pathogen or microbial toxin. Lyme disease, caused by Borrelia burgdorferi, is a tick-borne illness for which a human vaccine is not currently available. B. burgdorferi binds a tick salivary protein, Salp15, during transmission from the vector, and this interaction facilitates infection of mice. We now show that Salp15 antiserum significantly protected mice from B. burgdorferi infection. Salp15 antiserum also markedly enhanced the protective capacity of antibodies against B. burgdorferi antigens, such as OspA or OspC. Mice actively immunized with Salp15 were also significantly protected from tick-borne Borrelia. In vitro assays showed that Salp15 antiserum increased the clearance of Salp15-coated B. burgdorferi by phagocytes, suggesting a mechanism of action. Vaccination with a vector molecule that a microbe requires for infection of the mammalian host suggests a new strategy for the prevention of Lyme disease, and this paradigm may be applicable to numerous arthropod-borne pathogens of medical importance.
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Affiliation(s)
- Jianfeng Dai
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
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26
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Evans R, Mavin S, McDonagh S, Chatterton JMW, Milner R, Ho-Yen DO. More specific bands in the IgG western blot in sera from Scottish patients with suspected Lyme borreliosis. J Clin Pathol 2010; 63:719-21. [DOI: 10.1136/jcp.2010.076307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AimsTo identify further Western blot bands that may be specific in the diagnosis of Lyme borreliosis.MethodsThe Borrelia burgdorferi antibody profiles of 270 western blot positive patients and 241 western blot negative patients from 2008 were examined.Results27 different non-specific bands were detected in both groups. Six of 27 (22%) of the non-specific bands were detected significantly more in the western blot positive patients compared to the western blot negative patients (20 kDa, p<0.0001; 28 kDa, p<0.002; 36 kDa, p<0.002; 37 kDa, p<0.007; 48 kDa, p<0.023; 56 kDa, p<0.028; two-tailed F test).ConclusionResults suggest that the 20, 28 and 48 kDa bands should be regarded as specific.
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27
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McKay G, Gill I, Chauhan S. Lyme disease: an unusual case of peripheral nerve palsy. THE JOURNAL OF BONE AND JOINT SURGERY. BRITISH VOLUME 2010; 92:713-715. [PMID: 20436011 DOI: 10.1302/0301-620x.92b5.23345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Lyme disease is a vector-borne multisystem inflammatory disease caused by the spirochete Borrelia burgdorferi sensu lato. This disease is frequently seen in North America and to a lesser degree in Europe. However, its presence in England is uncommon and we present a case in which the patient developed a palsy of the common peroneal nerve.
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Affiliation(s)
- G McKay
- Trauma and Orthopaedic Department Royal Sussex County Hospital, BSUH NHS Trust, Eastern Road, Brighton, N2 5BE, UK
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Rhodes RG, Atoyan JA, Nelson DR. The chitobiose transporter, chbC, is required for chitin utilization in Borrelia burgdorferi. BMC Microbiol 2010; 10:21. [PMID: 20102636 PMCID: PMC2845121 DOI: 10.1186/1471-2180-10-21] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Accepted: 01/26/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The bacterium Borrelia burgdorferi, the causative agent of Lyme disease, is a limited-genome organism that must obtain many of its biochemical building blocks, including N-acetylglucosamine (GlcNAc), from its tick or vertebrate host. GlcNAc can be imported into the cell as a monomer or dimer (chitobiose), and the annotation for several B. burgdorferi genes suggests that this organism may be able to degrade and utilize chitin, a polymer of GlcNAc. We investigated the ability of B. burgdorferi to utilize chitin in the absence of free GlcNAc, and we attempted to identify genes involved in the process. We also examined the role of RpoS, one of two alternative sigma factors present in B. burgdorferi, in the regulation of chitin utilization. RESULTS Using fluorescent chitinase substrates, we demonstrated an inherent chitinase activity in rabbit serum, a component of the B. burgdorferi growth medium (BSK-II). After inactivating this activity by boiling, we showed that wild-type cells can utilize chitotriose, chitohexose or coarse chitin flakes in the presence of boiled serum and in the absence of free GlcNAc. Further, we replaced the serum component of BSK-II with a lipid extract and still observed growth on chitin substrates without free GlcNAc. In an attempt to knockout B. burgdorferi chitinase activity, we generated mutations in two genes (bb0002 and bb0620) predicted to encode enzymes that could potentially cleave the beta-(1,4)-glycosidic linkages found in chitin. While these mutations had no effect on the ability to utilize chitin, a mutation in the gene encoding the chitobiose transporter (bbb04, chbC) did block utilization of chitin substrates by B. burgdorferi. Finally, we provide evidence that chitin utilization in an rpoS mutant is delayed compared to wild-type cells, indicating that RpoS may be involved in the regulation of chitin degradation by this organism. CONCLUSIONS The data collected in this study demonstrate that B. burgdorferi can utilize chitin as a source of GlcNAc in the absence of free GlcNAc, and suggest that chitin is cleaved into dimers before being imported across the cytoplasmic membrane via the chitobiose transporter. In addition, our data suggest that the enzyme(s) involved in chitin degradation are at least partially regulated by the alternative sigma factor RpoS.
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Affiliation(s)
- Ryan G Rhodes
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI 02881, USA
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Abstract
Borrelia burgdorferi encodes a novel DNA-binding protein in the Fur/PerR family of transcriptional regulators termed BosR (BB0647). This issue of Molecular Microbiology contains two molecular genetic studies that help to clarify the function of BB0647 and resolve longstanding controversies. Loss of BB0647 appears to have a pronounced effect on borrelial gene expression and, in one study, caused significant in vitro growth defects. BB0647 was also found to be essential for infection of the mammalian host but not the tick vector. Both Ouyang et al. and Hyde et al. also demonstrate, quite unexpectedly, that BB0647 is required for induction of RpoS, an alternative sigma factor that controls a cadre of B. burgdorferi genes, most notably ospC, which enable the spirochetes to establish mammalian infection following tick inoculation. There are still many unanswered questions regarding the precise physiological role of BB0647, the most important of which relate to its homologues Fur and PerR: to what extent does it regulate either the response to oxidative stress and/or transition metal uptake? The mechanism(s) whereby BB0647 interfaces with the Rrp2-RpoN-RpoS pathway also remains to be discerned. However, these two seminal papers establish BB0647 (BosR) as a central player in the molecular biology and physiology of B. burgdorferi as well as the pathogenesis of Lyme disease.
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Affiliation(s)
- D Scott Samuels
- Division of Biological Sciences and Center for Biomolecular Structure and Dynamics, The University of Montana, Missoula, MT 59812-4824, USA.
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Ovat A, Muindi F, Fagan C, Brouner M, Hansell E, Dvořák J, Sojka D, Kopáček P, McKerrow JH, Caffrey CR, Powers JC. Aza-Peptidyl Michael Acceptor and Epoxide Inhibitors—Potent and Selective Inhibitors of Schistosoma mansoni and Ixodes ricinus Legumains (Asparaginyl Endopeptidases). J Med Chem 2009; 52:7192-210. [DOI: 10.1021/jm900849h] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Asli Ovat
- School of Chemistry and Biochemistry, and the Petit Institute for Bioscience and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - Fanuel Muindi
- School of Chemistry and Biochemistry, and the Petit Institute for Bioscience and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - Crystal Fagan
- School of Chemistry and Biochemistry, and the Petit Institute for Bioscience and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - Michelle Brouner
- School of Chemistry and Biochemistry, and the Petit Institute for Bioscience and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - Elizabeth Hansell
- Sandler Center for Basic Research in Parasitic Diseases, California Institute for Quantitative Biosciences, University of California, San Francisco, California 94158
| | - Jan Dvořák
- Sandler Center for Basic Research in Parasitic Diseases, California Institute for Quantitative Biosciences, University of California, San Francisco, California 94158
| | - Daniel Sojka
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, České Budějovice, CZ-370 05, Czech Republic
| | - Petr Kopáček
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, České Budějovice, CZ-370 05, Czech Republic
| | - James H. McKerrow
- Sandler Center for Basic Research in Parasitic Diseases, California Institute for Quantitative Biosciences, University of California, San Francisco, California 94158
| | - Conor R. Caffrey
- Sandler Center for Basic Research in Parasitic Diseases, California Institute for Quantitative Biosciences, University of California, San Francisco, California 94158
| | - James C. Powers
- School of Chemistry and Biochemistry, and the Petit Institute for Bioscience and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
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Marchal CM, Luft BJ, Yang X, Sibilia J, Jaulhac B, Boulanger NM. Defensin Is Suppressed by Tick Salivary Gland Extract During the In Vitro Interaction of Resident Skin Cells with Borrelia burgdorferi. J Invest Dermatol 2009; 129:2515-7. [DOI: 10.1038/jid.2009.73] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Overexpression of CsrA (BB0184) alters the morphology and antigen profiles of Borrelia burgdorferi. Infect Immun 2009; 77:5149-62. [PMID: 19737901 DOI: 10.1128/iai.00673-09] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Borrelia burgdorferi, the agent of Lyme disease, alters its gene expression in response to highly disparate environmental signals encountered in its hosts. Among the relatively few regulators of adaptive gene expression present in the borrelial genome is an open reading frame (ORF), BB0184, annotated as CsrA (carbon storage regulator A). CsrA, in several bacterial species, has been characterized as a small RNA binding protein that functions as a global regulator affecting mRNA stability or levels of translation of multiple ORFs. Consistent with known functions of CsrA, overexpression of CsrA from B. burgdorferi (CsrABb) in Escherichia coli resulted in reduced accumulation of glycogen. We determined that csrABb is part of the flgK motility operon and that the synthesis of CsrABb was increased when B. burgdorferi was propagated under fed-tick conditions. Overexpression of CsrABb in B. burgdorferi strain B31 (ML23, lp25-negative clonal isolate) resulted in a clone, designated ES25, which exhibited alterations in colony morphology and a significant reduction in the levels of FlaB. Several lipoproteins previously characterized as playing a role in infectivity were also altered in ES25. Real-time reverse transcription-PCR analysis of RNA revealed significant differences in the transcriptional levels of ospC in ES25, while there were no such differences in the levels of other transcripts, suggesting posttranscriptional regulation of expression of these latter genes. These observations indicate that CsrABb plays a role in the regulation of expression of pathophysiological determinants of B. burgdorferi, and further characterization of CsrABb will help in better understanding of the regulators of gene expression in B. burgdorferi.
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Promnares K, Kumar M, Shroder DY, Zhang X, Anderson JF, Pal U. Borrelia burgdorferi small lipoprotein Lp6.6 is a member of multiple protein complexes in the outer membrane and facilitates pathogen transmission from ticks to mice. Mol Microbiol 2009; 74:112-125. [PMID: 19703109 PMCID: PMC2754595 DOI: 10.1111/j.1365-2958.2009.06853.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Borrelia burgdorferi lipoprotein Lp6.6 is a differentially produced spirochete antigen. An assessment of lp6.6 expression covering representative stages of the infectious cycle of spirochetes demonstrates that the gene is solely expressed during pathogen persistence in ticks. Deletion of lp6.6 in infectious B. burgdorferi did not influence in vitro growth, or its ability to persist and induce inflammation in mice, migrate to larval or nymphal ticks or survive through the larval-nymphal molt. However, Lp6.6-deficient spirochetes displayed significant impairment in their ability to transmit from infected ticks to naïve mice, which was restored upon genetic complementation of the mutant with a wild-type copy of lp6.6, establishing that Lp6.6 plays a role in pathogen transmission from ticks to mammals. Lp6.6 is a subsurface, yet highly abundant, outer membrane antigen. Two-dimensional blue native/SDS-PAGE coupled with liquid chromatography-mass spectrometry (LC-MS/MS) analysis and protein cross-linking studies independently shows that Lp6.6 exists in multiple protein complexes in the outer membrane. We speculate that the function of Lp6.6 is connected to the physiological processes of these membrane complexes. Further characterization of differentially produced membrane antigens and associated protein complexes will likely aid in our understanding of the molecular details of B. burgdorferi persistence and transmission through a complex enzootic cycle.
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Affiliation(s)
- Kamoltip Promnares
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA.Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD 20742, USA.Department of Entomology, Connecticut Agricultural Experiment Station, New Haven, CT 06504, USA
| | - Manish Kumar
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA.Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD 20742, USA.Department of Entomology, Connecticut Agricultural Experiment Station, New Haven, CT 06504, USA
| | - Deborah Y Shroder
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA.Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD 20742, USA.Department of Entomology, Connecticut Agricultural Experiment Station, New Haven, CT 06504, USA
| | - Xinyue Zhang
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA.Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD 20742, USA.Department of Entomology, Connecticut Agricultural Experiment Station, New Haven, CT 06504, USA
| | - John F Anderson
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA.Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD 20742, USA.Department of Entomology, Connecticut Agricultural Experiment Station, New Haven, CT 06504, USA
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA.Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD 20742, USA.Department of Entomology, Connecticut Agricultural Experiment Station, New Haven, CT 06504, USA
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Abstract
One century after the first description of rickettsiae as human pathogens, the rickettsiosis remained poorly understood diseases. These microorganisms are indeed characterized by a strictly intracellular location which has, for long, prohibited their detailed study. Within the last ten years, the completion of the genome sequences of several strains allowed gaining a better knowledge about the molecular mechanisms involved in rickettsia pathogenicity. Here, we summarized available data concerning the critical steps of rickettsia-host cell interactions that should contribute to tissue injury and diseases, that is, adhesion, phagosomal escape, motility, and intracellular survival of the bacteria.
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Affiliation(s)
- Premanand Balraj
- Unité des Rickettsies, URMITE IRD-CNRS 6236, Faculté de Médecine, Marseille, France
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35
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Rhodes RG, Coy W, Nelson DR. Chitobiose utilization in Borrelia burgdorferi is dually regulated by RpoD and RpoS. BMC Microbiol 2009; 9:108. [PMID: 19473539 PMCID: PMC2700276 DOI: 10.1186/1471-2180-9-108] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Accepted: 05/27/2009] [Indexed: 12/03/2022] Open
Abstract
Background Borrelia burgdorferi has limited biosynthetic capabilities and must scavenge N-acetylglucosamine (GlcNAc), an essential component of the microbial cell wall, from the surrounding environment. Spirochetes cultured in the absence of free GlcNAc exhibit biphasic growth; however, addition of chitobiose (a dimer of GlcNAc) substitutes for free GlcNAc resulting in a single exponential phase. We evaluated the effect of RpoS and RpoN, the only alternative sigma factors in B. burgdorferi, on biphasic growth and chitobiose utilization in the absence of free GlcNAc. In addition, we investigated the source of GlcNAc in the second exponential phase. Results By comparing the growth of wild-type cells to insertional mutants for rpoS and rpoN we determined that RpoS, but not RpoN, partially regulates both biphasic growth and chitobiose utilization. The rpoS mutant, cultured in the absence of free GlcNAc, exhibited a significant delay in the ability to initiate a second exponential phase compared to the wild type and rpoS complemented mutant. Expression analysis of chbC, which encodes the membrane-spanning protein of the chitobiose phosphotransferase system, suggests the delay is due to the inability of the rpoS mutant to up regulate chbC. Furthermore, supplementing GlcNAc starved cultures with high concentrations (75 or 150 μM) of chitobiose resulted in biphasic growth of the rpoS mutant compared to a single exponential phase for the wild type and rpoS complemented mutant. In contrast, growth of the rpoN mutant under all conditions was similar to the wild type. 5' Rapid amplification of cDNA ends (5' RACE) revealed the transcriptional start site for chbC to be 42 bp upstream of the translational start site. Analysis of the chbC promoter region revealed homology to previously described RpoD and RpoS B. burgdorferi promoters. We also determined that yeastolate, a component of the growth medium (BSK-II), is not essential for second exponential phase growth. Conclusion Together these results suggest that RpoD and RpoS, but not RpoN, regulate biphasic growth and chitobiose utilization in B. burgdorferi by regulating the expression of the chitobiose transporter (chbC). The data also demonstrate that the second exponential phase observed in wild-type cells in the absence of free GlcNAc is not due to free chitobiose or GlcNAc oligomers present in the medium.
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Affiliation(s)
- Ryan G Rhodes
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI 02881, USA.
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36
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Tsao JI. Reviewing molecular adaptations of Lyme borreliosis spirochetes in the context of reproductive fitness in natural transmission cycles. Vet Res 2009; 40:36. [PMID: 19368764 PMCID: PMC2701186 DOI: 10.1051/vetres/2009019] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 04/15/2009] [Indexed: 02/04/2023] Open
Abstract
Lyme borreliosis (LB) is caused by a group of pathogenic spirochetes – most often Borrelia burgdorferi, B. afzelii, and B. garinii – that are vectored by hard ticks in the Ixodes ricinus-persulcatus complex, which feed on a variety of mammals, birds, and lizards. Although LB is one of the best-studied vector-borne zoonoses, the annual incidence in North America and Europe leads other vector-borne diseases and continues to increase. What factors make the LB system so successful, and how can researchers hope to reduce disease risk – either through vaccinating humans or reducing the risk of contacting infected ticks in nature? Discoveries of molecular interactions involved in the transmission of LB spirochetes have accelerated recently, revealing complex interactions among the spirochete-tick-vertebrate triad. These interactions involve multiple, and often redundant, pathways that reflect the evolution of general and specific mechanisms by which the spirochetes survive and reproduce. Previous reviews have focused on the molecular interactions or population biology of the system. Here molecular interactions among the LB spirochete, its vector, and vertebrate hosts are reviewed in the context of natural maintenance cycles, which represent the ecological and evolutionary contexts that shape these interactions. This holistic system approach may help researchers develop additional testable hypotheses about transmission processes, interpret laboratory results, and guide development of future LB control measures and management.
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Affiliation(s)
- Jean I Tsao
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48864, USA.
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37
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Borrelia burgdorferi bba74 is expressed exclusively during tick feeding and is regulated by both arthropod- and mammalian host-specific signals. J Bacteriol 2009; 191:2783-94. [PMID: 19218390 DOI: 10.1128/jb.01802-08] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although BBA74 initially was described as a 28-kDa virulence-associated outer-membrane-spanning protein with porin-like function, subsequent studies revealed that it is periplasmic and downregulated in mammalian host-adapted spirochetes. To further elucidate the role of this protein in the Borrelia burgdorferi tick-mammal cycle, we conducted a thorough examination of its expression profile in comparison with the profiles of three well-characterized, differentially expressed borrelial genes (ospA, ospC, and ospE) and their proteins. In vitro, transcripts for bba74 were expressed at 23 degrees C and further enhanced by a temperature shift (37 degrees C), whereas BBA74 protein diminished at elevated temperatures; in contrast, neither transcript nor protein was expressed by spirochetes grown in dialysis membrane chambers (DMCs). Primer extension of wild-type B. burgdorferi grown in vitro, in conjunction with expression analysis of DMC-cultivated wild-type and rpoS mutant spirochetes, revealed that, like ospA, bba74 is transcribed by sigma(70) and is subject to RpoS-mediated repression within the mammalian host. A series of experiments utilizing wild-type and rpoS mutant spirochetes was conducted to determine the transcriptional and translational profiles of bba74 during the tick-mouse cycle. Results from these studies revealed (i) that bba74 is transcribed by sigma(70) exclusively during the larval and nymphal blood meals and (ii) that transcription of bba74 is bracketed by RpoS-independent and -dependent forms of repression that are induced by arthropod- and mammalian host-specific signals, respectively. Although loss of BBA74 does not impair the ability of B. burgdorferi to complete its infectious life cycle, the temporal compartmentalization of this gene's transcription suggests that BBA74 facilitates fitness of the spirochete within a narrow window of its tick phase. A reexamination of the paradigm for reciprocal regulation of ospA and ospC, performed herein, revealed that the heterogeneous expression of OspA and OspC displayed by spirochete populations during the nymphal blood meal results from the intricate sequence of transcriptional and translational changes that ensue as B. burgdorferi transitions between its arthropod vector and mammalian host.
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38
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Ouyang Z, Blevins JS, Norgard MV. Transcriptional interplay among the regulators Rrp2, RpoN and RpoS in Borrelia burgdorferi. MICROBIOLOGY-SGM 2008; 154:2641-2658. [PMID: 18757798 DOI: 10.1099/mic.0.2008/019992-0] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The RpoN-RpoS alternative sigma factor pathway is essential for key adaptive responses by Borrelia burgdorferi, particularly those involved in the infection of a mammalian host. A putative response regulator, Rrp2, is ostensibly required for activation of the RpoN-dependent transcription of rpoS. However, questions remain regarding the extent to which the three major constituents of this pathway (Rrp2, RpoN and RpoS) act interdependently. To assess the functional interplay between Rrp2, RpoN and RpoS, we employed microarray analyses to compare gene expression levels in rrp2, rpoN and rpoS mutants of parental strain 297. We identified 98 genes that were similarly regulated by Rrp2, RpoN and RpoS, and an additional 47 genes were determined to be likely regulated by this pathway. The substantial overlap between genes regulated by RpoS and RpoN provides compelling evidence that these two alternative sigma factors form a congruous pathway and that RpoN regulates B. burgdorferi gene expression through RpoS. Although several known B. burgdorferi virulence determinants were regulated by the RpoN-RpoS pathway, a defined function has yet to be ascribed to most of the genes substantially regulated by Rrp2, RpoN and RpoS.
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Affiliation(s)
- Zhiming Ouyang
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jon S Blevins
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Michael V Norgard
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Deletion of BBA64, BBA65, and BBA66 loci does not alter the infectivity of Borrelia burgdorferi in the murine model of Lyme disease. Infect Immun 2008; 76:5274-84. [PMID: 18765733 DOI: 10.1128/iai.00803-08] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Borrelia burgdorferi, the causative agent of Lyme disease, alters its gene expression in response to highly disparate environmental signals encountered in its tick vector versus vertebrate hosts. Whole-genome transcriptional profile analysis of B. burgdorferi, propagated in vitro under mammalian-host-specific conditions, revealed significant upregulation of several linear plasmid 54 (lp54)-encoded open reading frames (ORFs). Among these ORFs, BBA64, BBA65, and BBA66 have been shown to be upregulated in response to multiple mammalian-host-specific signals. Recently, we determined that there was no significant difference in the ability of BBA64(-) mutant to infect C3H/HeN mice compared to its isogenic control strains, suggesting that B. burgdorferi might utilize multiple, functionally related determinants to establish infection. We further generated BBA65(-) and BBA66(-) single mutants in a noninfectious, lp25(-) clonal isolate of B. burgdorferi strain B31 (ML23) and complemented them with the minimal region of lp25 (BBE22) required for restoring the infectivity. In addition, we generated a BBA64(-) BBA65(-) BBA66(-) triple mutant using an infectious, clonal isolate of B. burgdorferi strain B31 (5A11) that has all of the infection-associated plasmids. There were no significant differences in the ability to isolate viable spirochetes from different tissues of C3H/HeN mice infected via intradermal needle inoculation with either the individual single mutants or the triple mutant compared to their respective isogenic parental strains at days 21 and 62 postinfection. These observations suggest that B. burgdorferi can establish infection in the absence of expression of BBA64, BBA65, and BBA66 in the murine model of Lyme disease.
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40
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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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Williamson HR, Benbow ME, Nguyen KD, Beachboard DC, Kimbirauskas RK, McIntosh MD, Quaye C, Ampadu EO, Boakye D, Merritt RW, Small PLC. Distribution of Mycobacterium ulcerans in buruli ulcer endemic and non-endemic aquatic sites in Ghana. PLoS Negl Trop Dis 2008; 2:e205. [PMID: 18365034 PMCID: PMC2268743 DOI: 10.1371/journal.pntd.0000205] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Accepted: 01/31/2008] [Indexed: 10/29/2022] Open
Abstract
Mycobacterium ulcerans, the causative agent of Buruli ulcer, is an emerging environmental bacterium in Australia and West Africa. The primary risk factor associated with Buruli ulcer is proximity to slow moving water. Environmental constraints for disease are shown by the absence of infection in arid regions of infected countries. A particularly mysterious aspect of Buruli ulcer is the fact that endemic and non-endemic villages may be only a few kilometers apart within the same watershed. Recent studies suggest that aquatic invertebrate species may serve as reservoirs for M. ulcerans, although transmission pathways remain unknown. Systematic studies of the distribution of M. ulcerans in the environment using standard ecological methods have not been reported. Here we present results from the first study based on random sampling of endemic and non-endemic sites. In this study PCR-based methods, along with biofilm collections, have been used to map the presence of M. ulcerans within 26 aquatic sites in Ghana. Results suggest that M. ulcerans is present in both endemic and non-endemic sites and that variable number tandem repeat (VNTR) profiling can be used to follow chains of transmission from the environment to humans. Our results suggesting that the distribution of M. ulcerans is far broader than the distribution of human disease is characteristic of environmental pathogens. These findings imply that focal demography, along with patterns of human water contact, may play a major role in transmission of Buruli ulcer.
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Pal U, Dai J, Li X, Neelakanta G, Luo P, Kumar M, Wang P, Yang X, Anderson JF, Fikrig E. A differential role for BB0365 in the persistence of Borrelia burgdorferi in mice and ticks. J Infect Dis 2008; 197:148-55. [PMID: 18171298 DOI: 10.1086/523764] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Borrelia burgdorferi, the etiologic agent of Lyme disease, persists in both an arthropod vector and vertebrate hosts, usually wild rodents. Analysis of the B. burgdorferi transcriptome in vivo indicates that the bb0365 gene is markedly induced as spirochetes enter the feeding ticks from infected mice. To understand the importance of the bb0365 gene product in the spirochete life cycle, we inactivated this gene in an infectious isolate of B. burgdorferi B31. BB0365-deficient spirochetes were fully pathogenic in mice and survived in diverse murine tissues. When naive ticks engorged on spirochete-infected mice, the B. burgdorferi bb0365 mutant entered ticks but had a markedly decreased survival rate compared with wild type B. burgdorferi. BB0365 therefore is not necessary for B. burgdorferi persistence in the vertebrate host but is required for survival of the Lyme disease agent within the feeding arthropod vector, and strategies for interfering with this gene may potentially interrupt the B. burgdorferi life cycle.
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Affiliation(s)
- Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA.
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43
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Abstract
The alternative sigma factor RpoS (sigma38 or sigmaS) plays a central role in the reciprocal regulation of the virulence-associated major outer surface proteins OspC and OspA in Borrelia burgdorferi, the Lyme disease spirochete. Temperature is one of the key environmental signals controlling RpoS, but the molecular mechanism by which the signal is transduced remains unknown. Herein, we identify and describe a small non-coding RNA, DsrABb, that regulates the temperature-induced increase in RpoS. A novel 5' end of the rpoS mRNA was identified and DsrABb has the potential to extensively base-pair with the upstream region of this rpoS transcript. We demonstrate that B. burgdorferi strains lacking DsrABb do not upregulate RpoS and OspC in response to an increase in temperature, but do regulate RpoS and OspC in response to changes in pH and cell density. Analyses of the rpoS and ospC steady-state mRNA levels in the dsrABb mutant indicate that DsrABb regulates RpoS post-transcriptionally. The 5' and 3' ends of DsrABb were mapped, demonstrating that at least four species exist with sizes ranging from 213 to 352 nucleotides. We hypothesize that DsrABb binds to the upstream region of the rpoS mRNA and stimulates translation by releasing the Shine-Dalgarno sequence and start site from a stable secondary structure. Therefore, we postulate that DsrABb is a molecular thermometer regulating RpoS in Borrelia burgdorferi.
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MESH Headings
- 5' Untranslated Regions/biosynthesis
- 5' Untranslated Regions/genetics
- 5' Untranslated Regions/metabolism
- Antigens, Bacterial/biosynthesis
- Antigens, Bacterial/genetics
- Bacterial Outer Membrane Proteins/biosynthesis
- Bacterial Outer Membrane Proteins/genetics
- Bacterial Proteins/biosynthesis
- Bacterial Proteins/genetics
- Base Pairing
- Base Sequence
- Blotting, Northern
- Blotting, Western
- Borrelia burgdorferi/genetics
- Borrelia burgdorferi/physiology
- Gene Expression Regulation, Bacterial/physiology
- Genetic Complementation Test
- Hydrogen-Ion Concentration
- Models, Biological
- Models, Molecular
- Molecular Sequence Data
- Nucleic Acid Conformation
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Untranslated/metabolism
- RNA, Untranslated/physiology
- Sequence Deletion
- Sigma Factor/biosynthesis
- Sigma Factor/genetics
- Temperature
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Affiliation(s)
- Meghan C Lybecker
- Division of Biological Sciences, The University of Montana, Missoula, MT 59812-4824, USA
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44
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Zipfel PF, Würzner R, Skerka C. Complement evasion of pathogens: common strategies are shared by diverse organisms. Mol Immunol 2007; 44:3850-7. [PMID: 17768102 DOI: 10.1016/j.molimm.2007.06.149] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2007] [Indexed: 01/24/2023]
Abstract
Infectious diseases represent a major health problem. Based on the limited efficacy of existing drugs and vaccines and the increasing antibiotic resistance new strategies are needed to fight infectious diseases. A better understanding of pathogen-host interaction is one important aspect to identify new virulence factors and antimicrobial and anti-inflammatory compounds utilized by pathogens represent an additional source for effective anti-inflammatory compounds. Complement forms a major defense line against invading microbes, and pathogens have learned during evolution to breach this defense line. The characterization of how pathogens evade complement attack is a rapidly developing field of current research. Pathogens mimic host surfaces and bind host complement regulators. Similarly pathogens utilize a number of complement inhibitory molecules which help to evade complement attack and which display anti-inflammatory activity. The molecular identification of these molecules, as well as the functional characterization of their roles at the pathogen-host interface is an important and emerging field of infection biology. In addition, pathogens utilize multiple sets of such regulators as redundancy and multiplicity is important for immune and complement evasion. Here we summarize the current scenarios of this emerging field which identifies multiple virulence factors and complement evasion strategies, but which at the same time reveals common mechanisms for immune and complement defense.
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Affiliation(s)
- Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Beutenbergstrasse 11a, D-07745 Jena, Germany.
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45
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Role of the BBA64 locus of Borrelia burgdorferi in early stages of infectivity in a murine model of Lyme disease. Infect Immun 2007; 76:391-402. [PMID: 17984202 DOI: 10.1128/iai.01118-07] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Borrelia burgdorferi, the causative agent of Lyme disease, undergoes rapid adaptive gene expression in response to environmental signals encountered during different stages of its life cycle in the arthropod vector or the mammalian host. Among all the plasmid-encoded genes of B. burgdorferi, several linear plasmid 54 (lp54)-encoded open reading frames (ORFs) exhibit the greatest differential expression in response to mammalian host-specific temperature, pH, and other uncharacterized signals. These ORFs include members of the paralogous gene family 54 (pgf 54), such as BBA64, BBA65, and BBA66, present on lp54. In an attempt to correlate transcriptional up-regulation of these pgf 54 members to their role in infectivity, we inactivated BBA64 and characterized the phenotype of this mutant both in vitro and in vivo. There were no major differences in the protein profiles between the BBA64 mutant and the control strains, while immunoblot analysis indicated that inactivation of BBA64 resulted in increased levels of BBA65. Moreover, there was no significant difference in the ability of the BBA64 mutant to infect C3H/HeN mice compared to that of its parental or complemented control strains as determined by culturing of viable spirochetes from infected tissues. However, enumeration of spirochetes using quantitative real-time PCR revealed tissue-specific differences, suggesting a minimal role for BBA64 in the survival of B. burgdorferi in select tissues. Infectivity analysis of the BBA64 mutant suggests that B. burgdorferi may utilize multiple determinants to establish infection in mammalian hosts.
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46
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Gilbert MA, Morton EA, Bundle SF, Samuels DS. Artificial regulation of ospC expression in Borrelia burgdorferi. Mol Microbiol 2007; 63:1259-73. [PMID: 17257307 DOI: 10.1111/j.1365-2958.2007.05593.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Outer surface lipoprotein (Osp) C is a virulence factor required for transmission of the Lyme disease agent, Borrelia burgdorferi. We have constructed an inducible promoter system to study the function and regulation of OspC by integrating regulatory elements from the Escherichia coli lac operon into the B. burgdorferi genome. An inducible promoter (flacp) was constructed by inserting a synthetic lac operator sequence between the transcriptional start site and the ribosomal binding site of the B. burgdorferi flgB promoter; flacp was then used to replace the native ospC and rpoS promoters in B. burgdorferi derivatives that constitutively express the E. coli Lac repressor protein (LacI). In vitro, the expression of ospC and rpoS from flacp was dependent on the inducer isopropyl beta-D-thiogalactopyranoside and was unaffected by temperature or pH, conditions commonly used to mimic different aspects of the B. burgdorferi life cycle. Our results suggest that OspC is essential immediately upon injection into a mouse and OspC expression must be maintained during the early stages of infection. In addition, the mouse infectivity experiment indicates that this system can be used to regulate B. burgdorferi genes in vivo, within the context of an experimental tick-mouse infectious cycle. RpoS is an alternative sigma factor that is required for ospC transcription. However, the role of other temperature-dependent factors has not previously been addressed. Our results with the inducible rpoS strain demonstrate that RpoS alone is sufficient to activate OspC expression, even at 23 degrees C. This is the first functional inducible promoter system developed for use in B. burgdorferi and, for the first time, will provide researchers with the ability to artificially regulate the expression of genes in this pathogenic spirochaete.
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Affiliation(s)
- Michael A Gilbert
- Division of Biological Sciences, The University of Montana, Missoula, MT 59812-4824, USA
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