Light-Controlled Modulation of 15-Lipoxygenase-1 Regulates Intestinal Inflammatory Signaling.

Photopharmacology offers powerful opportunities for the spatiotemporal control of biological processes, yet the rational design of photoswitchable enzyme inhibitors remains challenging. Here, we report a target-guided strategy for the development of diazo-based photoswitchable inhibitors of human 15-lipoxygenase-1 (15-LOX-1), a key enzyme in inflammatory signaling, ferroptosis, and cancer. Guided by the structural features of known ligands, we developed three complementary photoswitch classes: reversible azobenzenes (ABs), azo-heteroarenes (HAs), and covalent azo-bis-alkynes (BAs). These compounds exhibit efficient E/Z photoisomerization and high bistability, supported by single-crystal x-ray diffraction and density functional theory calculations. Enzymatic inhibitory and kinetic studies revealed distinct activity and selectivity profiles within the tested substrates/isoenzyme: AB and HA derivatives function as E-ON/Z-OFF inhibitors, whereas BA derivatives display Z-ON/E-OFF behavior, enabling programmable light-controlled modulation. We validated 15-LOX-1 as a therapeutic target in cellular and in vivo mouse models of colonic inflammation, where inhibition suppressed IL-8 expression. Finally, using our reversible and covalent photoswitches, we demonstrate photoisomer-dependent suppression of IL-8. Beyond 15-LOX-1, this work establishes a generalizable framework for the rational development of selective photoswitchable inhibitors with tunable biological outcomes.