Design, synthesis and biological evaluation of marine phidianidine-inspired derivatives against oxidized ldl-induced endothelial injury by activating Nrf2 anti-oxidation pathway

Inhibition of oxidized low-density lipoprotein (oxLDL)-induced vascular endothelial cell (VEC) injury is one of the effective strategies for treating atherosclerosis. In the present study, a series of novel marine phidianidine-inspired indole-1,2,4-oxadiazoles was designed, synthesized, and evaluated for their effects against oxLDL-induced injury in VECs. Among them, compound D-6, displaying the most effective protective activity, was found to inhibit oxLDL-induced apoptosis and the expression of ICAM-1 and VCAM-1 in VECs. Mechanistic studies showed that D-6 could trigger Nrf2 nuclear translocation, subsequently resulting in increased expression of Nrf2 target gene HO-1. Meanwhile, D-6 suppressed the increase of ROS level and nuclear translocation of NF-κB induced by oxLDL. Importantly, Nrf2 knockdown attenuated the inhibition effects of D-6 on oxLDL-induced apoptosis, ROS production and NF-κB nuclear translocation. Collectively, our studies demonstrated that compound D-6 protected against oxLDL-induced endothelial injury by activating Nrf2/HO-1 anti-oxidation pathway.