Discovery of Novel Indole-Based Allosteric Highly Potent ATX Inhibitors with Great In Vivo Efficacy in a Mouse Lung Fibrosis Model

Autotaxin (ATX) is the dominant catalytic enzyme accounting for the lipid mediator lysophosphatidic acid (LPA) through hydrolysis of lysophosphatidylcholine (LPC). There is great interest in developing nonacidic ATX inhibitors with a specific binding mode to serve as potential in vivo effective therapeutic tools. Herein, dating from a high-throughput screening (HTS) product Indole-1 (740 nM), a dedicated optimization campaign was implemented through derivatizing the -COOH group to versatile linkers that well-bridged the indole skeleton and the hydrophobic pocket binding groups. Ultimately, it was established that the coexistence of a carbamate linker and -OH-group-containing amines could generally furnish excellent indole-based ATX inhibitors with even below 1 nM in vitro activities. Two optimal entities were advanced to a bleomycin-induced mice pulmonary fibrosis model, which exerted promising efficacy in alleviating the damaged lung texture caused by bleomycin exposure. The novel carbamate-containing indole-based ATX inhibitors with a concrete binding mode may contribute to the identification of potential therapeutic agents to intervene in fibrotic diseases.