title: Intravital Imaging of Vascular Transmigration by the Lyme Spirochete: Requirement for the Integrin Binding Residues of the B. burgdorferi P66 Protein.
abstract: Vascular extravasation, a key step in systemic infection by hematogenous microbial pathogens, is poorly understood, but has been postulated to encompass features similar to vascular transmigration by leukocytes. The Lyme disease spirochete can cause a variety of clinical manifestations, including arthritis, upon hematogenous dissemination. This pathogen encodes numerous surface adhesive proteins (adhesins) that may promote extravasation, but none have yet been implicated in this process. In this work we report the novel use of intravital microscopy of the peripheral knee vasculature to study transmigration of the Lyme spirochete in living Cd1d-/-mice. In the absence of iNKT cells, major immune modulators in the mouse joint, spirochetes that have extravasated into joint-proximal tissue remain in the local milieu and can be enumerated accurately. We show that BBK32, a fibronectin and glycosaminoglycan adhesin of B. burgdorferi involved in early steps of endothelial adhesion, is not required for extravasation from the peripheral knee vasculature. In contrast, almost no transmigration occurs in the absence of P66, an outer membrane protein that has porin and integrin adhesin functions. Importantly, P66 mutants specifically defective in integrin binding were incapable of promoting extravasation. P66 itself does not promote detectable microvascular interactions, suggesting that vascular adhesion of B. burgdorferi mediated by other adhesins, sets the stage for P66-integrin interactions leading to transmigration. Although integrin-binding proteins with diverse functions are encoded by a variety of bacterial pathogens, P66 is the first to have a documented and direct role in vascular transmigration. The emerging picture of vascular escape by the Lyme spirochete shows similarities, but distinct differences from leukocyte transmigration.
authors.affiliation: Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada.|Department of Microbiology, Immunology & Infectious Diseases, University of Calgary, Calgary, Alberta, Canada.|Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Devender
authors.initials: D
authors.lastname: Kumar
authors.affiliation: Graduate Program in Microbiology, Immunology, and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America.|Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Ristow
authors.affiliation: Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada.|Department of Microbiology, Immunology & Infectious Diseases, University of Calgary, Calgary, Alberta, Canada.|Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Meiqing
authors.initials: M
authors.lastname: Shi
authors.affiliation: Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada.|Department of Microbiology, Immunology & Infectious Diseases, University of Calgary, Calgary, Alberta, Canada.|Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Mukherjee
authors.affiliation: Graduate Program in Microbiology, Immunology, and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America.|Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Caine
authors.affiliation: Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada.|Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Woo-Yong
authors.initials: WY
authors.lastname: Lee
authors.affiliation: Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada.|Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Kubes
authors.affiliation: Graduate Program in Microbiology, Immunology, and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America.|Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America.|Division of Infectious Diseases, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, Unites States of America.
authors.forename: Jenifer
authors.initials: J
authors.lastname: Coburn
authors.affiliation: Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada.|Department of Microbiology, Immunology & Infectious Diseases, University of Calgary, Calgary, Alberta, Canada.|Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada.
authors.forename: George
authors.initials: G
authors.lastname: Chaconas
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D025065:Borrelia burgdorferi / Q000472:pathogenicity*; D004195:Disease Models, Animal; D054884:Host-Pathogen Interactions / Q000502:physiology; D000069416:Intravital Microscopy; D008193:Lyme Disease / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D018272:Porins / Q000378:metabolism*; D057705:Transendothelial and Transepithelial Migration / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; C107893:Oms66 protein, Borrelia; D018272:Porins