OspC's Pivotal Role in Lyme Disease Infection and Transmission

Abstract

The Olathe North MSOE Center for BioMolecular Modeling SMART Team used 3‐D modeling and printing technology to examine structure‐function of OspC. Lyme disease is a tick‐borne illness caused by the spirochetal bacterium Borrelia burgdorferi. It is the most commonly occurring vector‐borne disease in the United States and if not treated, Lyme disease can cause carditis, arthritis and neurological symptoms. The surface of B. burgdorferi is covered by surface lipoproteins. One of them is the outer surface lipoprotein C (OspC). The ospC gene is located on a plasmid and expressed by the bacteria during their transmission from ticks to warm‐blooded hosts. OspC is critical for colonization of the host and begins to be synthesized by the bacteria when the blood and its nutrients enters the tick's midgut upon a tick bite. The presence of OspC promotes the movement of B. burgdorferi from the midgut to the salivary glands, allowing the bacteria to be injected with the tick saliva into the host. The tick salivary protein Salp15 binds to portions of OspC and interferes with the initial host immune response, which allows the bacteria to spread to different tissues. OspC also binds plasminogen which is activated by host to the protease plasmin. The resulting coat of plasmin breaks down host tissues and offers the bacteria a pathway to disseminate further. The OspC protein is a homodimer consisting of a bundle of multiple alpha helices as well as a single beta‐pleated sheet. A region facing away from the bacterial membrane is negatively charged and may bind positively charged host ligands. This feature is unique to OspC variants that are known to cause invasive human disease. The precise biological function of OspC is unclear and its relationship between OspC variant and pathogenicity is not well understood. To further study this, mutations within, e.g,, the above mentioned negatively charged region may affect the bacteria's ability bind Salp15 or plasminogen and thus disrupt the overall effectiveness of Borrelia burgdorferi to be transmitted and cause disease.Support or Funding InformationOlathe North High School SMART TeamSponsor: Chris ElniffMentor: Dr. Wolfram Zückert, PhD, Microbiology, Molecular Genetics and Immunology, University of Kansas Medical CenterThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.