Mechanisms of cannabinoid-resistance among oral spirochetes

PROJECT SUMMARY Periodontitis, a microbial-driven, destructive disease of the tissues surrounding the teeth, occurs in approximately 50% of the population and is associated with several debilitating systemic conditions, including vascular and lung diseases, diabetes mellitus, pre-term birth, specific cancers and Alzheimer’s disease. Patients who smoke marijuana have increased susceptibility to periodontitis. Indeed, the most recent epidemiological evidence suggests that marijuana both exacerbates the severity of disease and induces periodontal disease at a significantly younger age than is normal. One key predisposing mechanism is likely to be the induction of a disease-related dysbiotic plaque by cannabis. Based on a preliminary study of the oral microbiome of cannabis users and non-users, we have shown that – unlike many oral bacteria – Treponema putidum and multiple strains of Treponema denticola are resistant to physiological and supraphysiological doses of the primary anti-microbial phytocannabinoids (CBN, CBD, THC). We have also identified CBD-regulated genes involved in transcriptional regulation and toxin control that help explain such resistance in the T. denticola type strain, ATCC 35405. We now plan to extend these studies by (Aim 1) identifying further phytocannabinoid resistant oral spirochetes; delineating their individual responses to phytocannabinoid-induced stress; and generating the first oral spirochete pantranscriptome in the context of the spirochetal pangenome. Thus, we will identify species-specific and global, pan- spirochetal CBD-related resistance and virulence traits. In Aim 2 we will generate mutants (and complemented strains) in ubiquitously CBD-regulated genes and assess their cannabinoid-related fitness thus facilitating future, in depth comparative fitness and other mechanistic studies at the R01 level.