Fragment-Based Development of Small Molecule Inhibitors Targeting Mycobacterium tuberculosis Cholesterol Metabolism

Tuberculosis is the deadliest infectious disease in history and new drugs are urgently required to combat multidrug-resistant (MDR) strains of Mycobacterium tuberculosis (Mtb). Here, we exploit the relience of Mtb on host-derived cholesterol to develop a novel class of antitubercular compounds that target Mtb CYP125 and CYP142; the enzymes that catalyze the first step of cholesterol metabolism. A combination of fragment screening and structure-based drug design was used to identify a hit compound and guide synthetic optimization of a dual CYP125/142 ligand 5m (K_D 40-160 nM), which potently inhibits enzyme activity in vitro (K_I < 100 nM), and the growth of Mtb in extracellular (MIC₉₉ 0.4-1.5 μM) and intracellular assays (IC₅₀ 1.7 μM). The structural data and lead compounds reported here will help study Mtb cholesterol metabolism and guide the development of novel antibiotics to combat MDR Mtb.