Fab'-bearing siRNA TNF?-loaded nanoparticles targeted to colonic macrophages offer an effective therapy for experimental colitis.
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ABSTRACT: Patients suffering from inflammatory bowel disease (IBD) are currently treated by systemic drugs that can have significant side effects. Thus, it would be highly desirable to target TNF? siRNA (a therapeutic molecule) to the inflamed tissue. Here, we demonstrate that TNF? siRNA can be efficiently loaded into nanoparticles (NPs) made of poly (lactic acid) poly (ethylene glycol) block copolymer (PLA-PEG), and that grafting of the Fab' portion of the F4/80 Ab (Fab'-bearing) onto the NP surface via maleimide/thiol group-mediated covalent bonding improves the macrophage (MP)-targeting kinetics of the NPs to RAW264.7 cells in vitro. Direct binding was shown between MPs and the Fab'-bearing NPs. Next, we orally administered hydrogel (chitosan/alginate)-encapsulated Fab'-bearing TNF?-siRNA-loaded NPs to 3% dextran sodium sulfate (DSS)-treated mice and investigated the therapeutic effect on colitis. In vivo, the release of TNF?-siRNA-loaded NPs into the mouse colon attenuated colitis more efficiently when the NPs were covered with Fab'-bearing, compared to uncovered NPs. All DSS-induced parameters of colonic inflammation (e.g., weight loss, myeloperoxidase activity, and I?b? accumulation) were more attenuated Fab'-bearing NPs loaded with TNF? siRNA than without the Fab'-bearing. Grafting the Fab'-bearing onto the NPs improved the kinetics of endocytosis as well as the MP-targeting ability, as indicated by flow cytometry. Collectively, our results show that Fab'-bearing PLA-PEG NPs are powerful and efficient nanosized tools for delivering siRNAs into colonic macrophages.
SUBMITTER: Laroui H
PROVIDER: S-EPMC4100604 | biostudies-literature | 2014 Jul
REPOSITORIES: biostudies-literature
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