Rapamycin-Gliadin Composite Nanoparticles Enhance Hepato-Splenic Dialogue for Gluten Tolerance in Celiac Disease

Background Celiac disease (CeD) is an autoimmune disorder triggered by gluten, with gliadin as the primary antigen. Therapies targeting gliadin to induce antigen-specific immune tolerance are of significant interest. This study investigates the therapeutic potential of a novel rapamycin-gliadin composite nanoparticle (PLN-GR) in enhancing Kupffer cell-mediated hepato-splenic dialogue to promote gluten tolerance in CeD. Methods Rapamycin-gliadin composite nanoparticles were synthesized using a precipitation self-assembly method and characterized for size, zeta potential, and cellular uptake. A CeD delayed-type hypersensitivity (DTH) mouse model was employed to evaluate the immunomodulatory effects of PLN-GR. Cellular biodistribution, immune phenotyping, and metabolic assessments were conducted to elucidate the nanoparticles' mechanism of action. Results Rapamycin-gliadin composite nanoparticles effectively targeted the liver and were internalized by Kupffer cells, inducing a tolerogenic phenotype. In vivo treatment with PLN-GR ameliorated systemic and intestinal inflammation in the CeD DTH mouse model, evidenced by reduced paw swelling and intestinal histopathology. The nanoparticles induced a metabolic shift from glycolysis to oxidative phosphorylation in macrophages, associated with increased itaconate production. This metabolic reprogramming was linked to an increase in PD-L1+ tolerogenic dendritic cells and a decrease in Th1 cell counts in the spleen. Conclusion The study demonstrates that rapamycin-gliadin nanoparticles can induce antigen-specific tolerance in CeD by modulating hepatic and splenic immune responses. The findings suggest a potential therapeutic strategy for CeD by enhancing immunometabolic reprogramming and inter-organ communication.