Hypercholesterolemia and Lyme disease. The goal of this project is to determine the effects of hyperlipidemia in the pathogenicity and persistency of Borrelia burgdorferi in the host. At present, little is known regarding the effects of hypercholesterolmia levels or the accumulation of fat in tissues targeted by B. burgdorferi in Lyme disease patients. In a recent study, we showed that elevated levels of serum cholesterol, achieved with a short term high fat diet in cholesterol-transport deficient mice resulted in increased arthritis as well as increased number of spirochetes in the joints. These results alerted us to the possibility that hyperlipidemias could be a comorbidity factor for Lyme disease.
Characterization of lipid rafts in Borrelia burgdoferi.
Lipid rafts are microdomains present in the membrane of eukaryotic organisms and bacterial pathogens. They are characterized by having tightly packed lipids and a subset of specific proteins. Lipid rafts are associated with a variety of important biological processes including signaling and lateral sorting of proteins. We have analyzed the lipid constituents present in the outer and inner membranes of Borrelia and we have found that both membranes have cholesterol and cholesterol glycolipids. Fluorescence anisotropy and FRET showed that lipids from both membranes can form rafts but have different abilities to do so. The analysis of the biochemically-defined proteome of lipid rafts from the inner and outer membranes suggest that are implicated in different biological processes.
Uptake and use of cholesterol by Borrelia burgdoferi
Tick microbiome and tick borne pathogens. Tick-borne pathogens not only face a harsh environment in the tick (i.e., lack of nutrients, tick immune system) but also encounter other bacteria including other tick-borne pathogens as well as members of the tick microbiome. Little is know regarding the interactions among bacteria in the midgut and whether this affects the tick’s fitness and shapes the ability of pathogens to colonize the tick midgut.