Lyme disease is the most prevalent tick-borne disease in the USA and affects the heart, joints, skin, musculoskeletal and nervous systems. Recently, the reported cases in the USA have increased to e20,000 per year. The causative agent, Borrelia burgdorferi, often persists in the face of a strong immune response and can result in incapacitating chronic disease manifestations, such as arthritis or neuroborreliosis. My long-term goal is to describe the host-bacterial interactions essential for establishment of the bacterial infection and consequently Lyme disease. Colonization of various tissues by many microbial pathogens requires attachment to cells or extracellular matrix (ECM). Glycosaminoglycans (GAGs) are carbohydrate units of proteoglycans, which are ubiquitously expressed ECM components on mammalian cells. Our extensive studies show that GAG-binding is a major adherence mechanism of B. burgdorferi. Indeed, we have shown that B. burgdorferi produces several GAG- binding adhesins, including, (i) DbpA and DbpB, (ii) Borrelia GAG-binding Protein (Bgp), and (iii) BBK32. Consistent with the multiplicity of GAG-binding adhesins, mutants lacking one or two documented adhesins of Lyme spirochetes retain some degree of infectivity. B. burgdorferi dbpA-dbpB double deletion mutants, generated in a variety of strain backgrounds, our B. burgdorferi bgp mutants, and bbk32 mutants remain infectious in immunocompetent mice. At least first three of these exhibit colonization defect. Bgp also exhibits 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase activity. However, it is not known if the colonization defect of the bgp mutant is related to its GAG-binding activity, its nucleosidase activity, or both. To determine if the defect in colonization by a bgp mutant is related to its GAG-binding, its enzymatic activity, or both, and whether Bgp displays partial functional redundancy with other GAG-binding adhesins, the following aims will be pursued. (1). Delineate the GAG-binding and MTA/SAH nucleosidase activities of Bgp. (2). Define the activity of Bgp required for colonization during infection. (3). Assess the functional redundancy of Bgp with other GAG-binding adhesins during colonization. Significance. We first recognized Bgp as a multifunctional surface protein, observed its role in tissue colonization during mouse infection, and determined it to be a target of novel drugs. This study will genetically delineate two activities of Bgp to assess if one or both activities are required during infection. We will also determine if defect in Bgp and DbpA-DbpB production is additive or each contribute to the tissue- specific colonization by B. burgdorferi. Such an understanding of the spirochete-GAG interactions involving Bgp, DbpA and DbpB, on Lyme pathogenesis and of the role of Bgp as a metabolic enzyme could help design better diagnostic tests and facilitate the development of novel treatment strategies, especially for the later stages of Lyme disease.

Public Health Relevance

Glycosamioglycan-mediated adherence of Lyme spirochetes to various mammalian cells appears to be a critical initial step during infection and also plays an important contribution in tissue colonization. Bgp is a GAG-binding adhesin that also exhibits 5'-methylthioadenosine/S-adenosylhomocysteine (MTA/SAH) nucleosidase activity. We will evaluate importance of these two activities of Bgp for infection in the mouse model and determine if Bgp-DbpA and DbpB are the major GAG-binding proteins required for B. burgdorferi pathogenesis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
6R01AI089921-03
Application #
8493982
Study Section
Bacterial Pathogenesis Study Section (BACP)
Program Officer
Breen, Joseph J
Project Start
2011-07-01
Project End
2016-06-30
Budget Start
2013-07-01
Budget End
2014-06-30
Support Year
3
Fiscal Year
2013
Total Cost
$336,285
Indirect Cost
$124,785
Name
Rutgers University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
078795851
City
Newark
State
NJ
Country
United States
Zip Code
07103
Chan, Kamfai; Casjens, Sherwood; Parveen, Nikhat (2012) Detection of established virulence genes and plasmids to differentiate Borrelia burgdorferi strains. Infect Immun 80:1519-29