Defining the role of sphingolipids on Porphyromonas gingivalis outer membrane vesicle uptake and elicited inflammation

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ABSTRACT The proposed work outlined in the training plan for this NRSA Individual Predoctoral Fellowships to Promote Diversity in Health-Related Research (F31) Award will support fourth year pre-doctoral candidate Zavier Eure throughout his graduate program at University of Florida. Mr. Eure has displayed phenomenal excellence in his academics and his learning of new lab techniques while being in the UF BMS program and currently supported by the Oral Biology Department R90/T90 Training Grant. The research and training plan for Mr. Eure will provide him a repertoire of skills needed to matriculate to the next level of his pre-doctoral training and also opportunities to further advance his career and professional development. Being awarded this F31 will offer Mr. Eure the ability to achieve his long-term goal of becoming a leader in science and provide a significant contribution to the field of biomedical research. Periodontal disease is a highly prevalent chronic inflammatory disease affecting up to 42% of adults in the US over the age of 30. Periodontal disease is orchestrated by various microorganisms that make up the subgingival microbiota. In susceptible individuals, dysbiosis of the subgingival microbiota promotes a dysregulated inflammation that causes an irreversible destruction of the soft and hard tissues supporting the teeth. Porphyromonas gingivalis (Pg) is an oral bacterium commonly associated with the microbial dysbiosis leading to periodontal disease. Pg is referred to as a pathobiont because its known to manipulate the host inflammatory milieu to facilitate disease states, however Pg can also remain in the oral cavity during healthy states. The various mechanisms behind how Pg contributes to the changing inflammatory milieu is yet to be identified. Our lab has discovered Pg sphingolipids (SLs) limit host inflammation and host cell SL transfer via outer membrane vesicles is a potential transport mechanism for Pg. The mechanism of OMV uptake by host cells is known to impact elicited inflammation and OMV composition (SL+ or SL-) plays an important role in the route for OMV uptake. Myeloid differentiation factor 88 (MyD88) is also known to be involved in the innate immune sensing of Pg OMVs and has been found to be a target for immunomodulation by Pg. I hypothesize Pg SLs facilitates an OMV uptake mechanism that limits inflammation and that SLs promote an immunomodulatory mechanism linked to targeting of MyD88. I plan to use the THP-1 human cell line and primary human macrophages to characterize the uptake mechanism of SL-containing Pg OMVs (Aim 1) and to determine the role of MyD88 in Pg SL-mediated immunomodulation (Aim 2).