ROS-responsive nanoparticles for oral delivery of luteolin and targeted therapy of ulcerative colitis by regulating pathological microenvironment

Oxidative stress, caused by excessive production of reactive oxygen species (ROS), plays a crucial role in the occurrence and development of ulcerative colitis (UC). We developed ROS-responsive nanoparticles (NPs) as an efficacious nanomedicine against UC with oral administration. The NPs were fabricated with a D-alpha-tocopherol polyethylene glycol succinate-b-poly(beta-thioester) copolymer (TPGS-PBTE) for ROS cleavage via the colitis targeted delivery of luteolin (LUT), a natural flavonoid with good anti-inflammation and radical-scavenging activity. Owing to the thioether bond in the polymer main chain, the TPGS-PBTE NPs exhibited an ROS-responsive size change and drug release, which benefited the ROS-scavenging and selective accumulation of LUT in the inflamed colon. In a dextran sulfate sodium-induced acute colitis murine model, LUT@TPGS-PBTE NPs alleviated body weight loss, colon length shortening, and damage to the colonic tissues due to the suppression of ROS and proinflammatory cytokines (e.g., IL-17A, IL-6, interferon-gamma, tumor necrosis factor-alpha), as well as upregulation of glutathione and anti-inflammatory factors (e.g., IL-10, IL-4). More importantly, LUT@TPGS-PBTE NPs regulated the inflammatory microenvironment by modulating the T helper (Th)1/Th2 and Th17/regulatory T cell (Treg) balance (i.e., increased numbers of Tregs and Th2 cells and decreased numbers of Th1 and Th17 cells), thus resolving inflammation and accelerating the healing of the intestinal mucosa. Additionally, the LUT@TPGS-PBTE NPs formulation enabled the reduction of the effective dose of LUT and showed excellent biosafety in the mouse model, demonstrating its potential as a targeted UC therapeutic oral preparation.

Automated summary

This study developed ROS-responsive nanoparticles for targeted therapy of ulcerative colitis (UC). The nanoparticles showed selective accumulation in the inflamed colon, effectively scavenged reactive oxygen species (ROS), and exerted anti-inflammatory effects. In a UC mouse model, the nanoparticles alleviated symptoms, regulated the inflammatory microenvironment, and accelerated intestinal mucosal healing.