Discovery of a Highly Potent and Selective Small-Molecule Inhibitor of <i>In Vivo</i> Anaerobic Choline Metabolism by Human Gut Bacteria

Trimethylamine (TMA) Lyase is an enzyme expressed in human gut bacteria that plays a pivotal role in the formation of trimethylamine oxide (TMAO), a metabolite implicated in the development of heart failure. Here, we describe a strategy to design covalent inhibitors targeting the active site thiyl radical involved in the catalytic cycle of the enzyme under anaerobic conditions. This strategy led to the discovery of <b>7</b>, a previously unreported highly potent and selective inhibitor of TMA Lyase. When dosed orally to rats, <b>7</b> shows a significant reduction of circulating TMAO levels and, importantly, demonstrates inhibition of TMAO generated from a human microbiome when profiled in a human fecal mouse transplant model.