Enzyme/ROS dual-sensitive nanoplatform with on-demand Celastrol release capacity for enhanced ulcerative colitis therapy by ROS scavenging, microbiota rebalancing, inflammation alleviating.

Background: The oral administration of drugs for treating ulcerative colitis (UC) is hindered by several factors, including inadequate gastrointestinal stability, insufficient accumulation in colonic lesions, and uncontrolled drug release. Methods: A multiple sensitive nano-delivery system comprising β-cyclodextrin (CD) and 4-(hydroxymethyl)phenylboronic acid (PAPE) with enzyme/reactive oxygen species (ROS) sensitivity was developed to load celastrol (Cel) as a comprehensive treatment for UC. Results: Owing to the positive charge in the site of inflamed colonic mucosa, the negatively charged nanomedicine (Cel/NPs) could efficiently accumulate. Expectedly, Cel/NPs showed excellent localization ability to colon in vitro and in vivo tests. The elevated concentration of ROS and intestinal enzymes in the colon microenvironment quickly break the CD, resulting in Cel release partially to rebalance microbiota and recover the intestinal barrier. The accompanying cellular internalization of residual Cel/NPs, along with the high concentration of cellular ROS to trigger Cel burst release, could decrease the expression of inflammatory cytokines, inhibit colonic cell apoptosis, promote the macrophage polarization, scavenge ROS, and regulate the TLR4/NF-κB signaling pathway, which certified that Cel/NPs possessed a notably anti-UC therapy outcome. Conclusions: We provide a promising strategy for addressing UC symptoms via an enzyme/ROS-sensitive oral platform capable of releasing drugs on demand. [ABSTRACT FROM AUTHOR]