Abstract 430: Development of a Gut-microbe Targeted Non-lethal Therapeutic to Inhibit Thrombosis Potential Without Enhanced Bleeding

Abstract

Recent clinical and animal studies show trimethylamine-N-oxide (TMAO), a microbiota-dependent metabolite derived from trimethylamine (TMA)-containing nutrients abundant in a Western diet, both promotes platelet hyperresponsiveness and thrombosis potential and is predictive of incident atherothrombotic event risks in large-scale clinical investigations. Utilizing a mechanism-based inhibitor approach targeting a major gut microbial enzyme (CutC/D) in the TMAO meta-organismal pathway, we developed choline analogues with cryptic reactive moieties that upon interaction with the microbial TMA generating enzyme, display potent, time-dependent and irreversible inhibition without affecting commensal microbial viability. In animal models, a single oral dose of mechanism-based microbial choline TMA lyase inhibitor significantly reduced (> 95% inhibition, p < 0.0001) plasma TMAO levels over a sustained period of time (up to 3 days), while limiting systemic exposure in the host. This was achieved by the selective accumulation of inhibitor at the site of action, within intestinal microbes, to millimolar levels, a concentration over a million-fold higher than needed for therapeutic effect. In animal models, inhibition of microbial TMA generation was shown to rescue diet-induced platelet hyperresponsiveness and enhanced thrombosis potential, both without increasing enhanced bleeding risk and observable toxicity. The present studies reveal mechanism-based inhibition of microbial TMA lyase activity as a therapeutic target for reducing thrombosis potential, a critical adverse complication in heart disease. They also suggest mechanism-based inhibitors designed to concomitantly accumulate within the gut microbe may serve as a generalizable approach for the selective targeting of microbial catabolic enzymes linked to host diseases, while limiting systemic exposure in the host.