Harnessing Kupffer Cell Metabolic Rewiring: Rapamycin-Gliadin Nanoparticle as a Pivotal Strategy for Immune Tolerance in Celiac Disease

Celiac disease (CeD), triggered by gliadin exposure, necessitates therapeutic strategies that establish an antigen-specific immune tolerance. This study explores the therapeutic efficacy and mechanism of rapamycin-gliadin composite nanoparticles (PLN-GR) for CeD treatment. In vivo analyses demonstrated the efficient uptake of PLN-GR by antigen-presenting cells (APCs), particularly Kupffer cells and splenic dendritic cells (DCs), driving their tolerogenic phenotypic transformation. In a murine CeD model, PLN-GR administration significantly enhanced gluten tolerance and mitigated intestinal inflammation, as indicated by reduced paw edema and improved histopathological parameters. Mechanistically, PLN-GR induced macrophage metabolic reprogramming from glycolysis to Oxidative Phosphorylation, concomitant with elevated serum itaconate levels. This metabolic shift potentiated interorgan immunoregulatory crosstalk, expanding PD-L1⁺ tolerogenic splenic DCs while suppressing pathogenic Th1 cell populations. Bone marrow-derived macrophages (BMDMs) from Acod1^-/- mice (deficient in itaconate synthesis) failed to induce DC tolerance upon PLN-GR treatment. However, supplementation with the itaconate derivative 4-octyl itaconate (4-OI) restored PD-L1 expression in DC2.4 cells in vitro, revealing that itaconate induces and stabilizes the tolerant DC phenotype. These findings underscore PLN-GR as a novel nanotherapeutic platform for CeD, achieving gliadin-specific tolerance through hepatic-splenic immunometabolic reprogramming and itaconate-dependent PD-L1 regulation, thereby offering a translatable strategy for autoimmune disease management.