Interactions of the Treponema pallidum adhesin Tp0751 with the human vascular endothelium

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dc.contributor.authorLithgow, Karen V.
dc.contributor.supervisorCameron, Caroline E.
dc.date.accessioned2019-07-30T17:02:12Z
dc.date.copyright2019en_US
dc.date.issued2019-07-30
dc.degree.departmentDepartment of Biochemistry and Microbiologyen_US
dc.degree.levelDoctor of Philosophy Ph.D.en_US
dc.description.abstractTreponema pallidum ssp. pallidum is the causative agent of syphilis, a sexually transmitted infection characterized by multi-stage disease and diverse clinical manifestations. Treponema pallidum undergoes rapid vascular dissemination to penetrate tissue, placental, and blood-brain barriers and gain access to distant tissue and organ sites. The rapidity and extent of T. pallidum dissemination is well documented, but the molecular mechanisms that underlie this process have yet to be fully elucidated. Tp0751 is a T. pallidum adhesin that interacts with vascular factors and mediates adherence to endothelial cells under shear flow. This dissertation explores the molecular interactions and functional outcomes of Tp0751-mediated vascular endothelium adhesion. The findings presented herein demonstrate that recombinant Tp0751 adheres to human macrovascular and microvascular endothelial cells, including cerebral brain endothelial cells. This interaction is confirmed using live T. pallidum, where spirochete- endothelial cells interactions are disrupted with Tp0751-specific antiserum. Further, the 67 kDa laminin receptor (LamR) is identified as an endothelial receptor using affinity chromatography coupled with mass spectrometry to isolate and identify Tp0751-interacting proteins from endothelial cells membrane extracts. Notably, LamR is a brain endothelial cell receptor for other neurotropic invasive pathogens. Evaluation of endothelial intercellular junctions reveals that recombinant Tp0751 and live T. pallidum disrupt junctional architecture. However, transwell solute flux assays reveal that Tp0751 and T. pallidum do not alter endothelial barrier integrity. The transendothelial migration of T. pallidum can be partially abrogated with an endocytosis inhibitor, implying a transcellular route for barrier traversal. However, a subpopulation of T. pallidum localizes to intercellular junctions, indicating paracellular traversal may also be employed. These findings enhance our understanding of the mechanics of T. pallidum attachment to endothelial cells and suggest that T. pallidum may use both paracellular and transcellular mechanisms to traverse the vascular endothelium without altering barrier permeability. A more complete understanding of this process will facilitate vaccine development for syphilis.en_US
dc.description.embargo2020-06-18
dc.description.scholarlevelGraduateen_US
dc.identifier.bibliographicCitationParker, M. L., S. Houston, H. Petrosova, K. V. Lithgow, R. Hof, C. Wetherell, W. C. Kao, Y. P. Lin, T. J. Moriarty, R. Ebady, C. E. Cameron, and M. J. Boulanger. 2016. 'The Structure of Treponema pallidum Tp0751 (Pallilysin) Reveals a Non-canonical Lipocalin Fold That Mediates Adhesion to Extracellular Matrix Components and Interactions with Host Cells', PLoS Pathog, 12: e1005919.en_US
dc.identifier.bibliographicCitationKao, W. A., H. Petrosova, R. Ebady, K. V. Lithgow, P. Rojas, Y. Zhang, Y. E. Kim, Y. R. Kim, T. Odisho, N. Gupta, A. Moter, C. E. Cameron, and T. J. Moriarty. 2017. 'Identification of Tp0751 (Pallilysin) as a Treponema pallidum Vascular Adhesin by Heterologous Expression in the Lyme disease Spirochete', Sci Rep, 7: 1538.en_US
dc.identifier.urihttp://hdl.handle.net/1828/10995
dc.languageEnglisheng
dc.language.isoenen_US
dc.rightsAvailable to the World Wide Weben_US
dc.subjectsyphilisen_US
dc.subjectTreponema pallidumen_US
dc.subjectmicrobiologyen_US
dc.subjectvascular disseminationen_US
dc.subjectsexually transmitted infectionen_US
dc.subjectpathogenesisen_US
dc.subjectvascular adhesinen_US
dc.titleInteractions of the Treponema pallidum adhesin Tp0751 with the human vascular endotheliumen_US
dc.typeThesisen_US

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