Inhibition of cGAS in dendritic cells suppresses maturation and prolongs allograft survival in mice

Cyclic GMP-AMP synthase (cGAS) is critical for dendritic cell (DC) maturation. This study investigates how cGAS suppression in DCs influences graft immune tolerance. Bioinformatics analysis assessed cGAS involvement in transplant immunity. Immature DCs were transduced with an adenoviral vector to knockdown cGAS and divided into three groups: cGAS-shRNA-DCs, EGFP-DCs and PBS (control). These were administered intravenously before transplantation to establish a mouse model. Graft survival and histopathology were evaluated. Splenic T cell subsets were analyzed by flow cytometry. After lipopolysaccharide stimulation, MHC-II and co-stimulatory molecule expression, antigen uptake, and T cell proliferation were measured in three groups. Cytokine levels in supernatants were quantified. Western blotting was used to explore the mechanism of cGAS in DC maturation. Bioinformatics revealed elevated cGAS expression in allografts. cGAS-shRNA-DCs showed reduced MHC-II and co-stimulatory molecule expression, enhanced phagocytosis, and decreased T cell activation. IFN-γ, IL-1β, TNF-α, and IL-6 levels were lower, while IL-10 was higher. Mice receiving cGAS-shRNA-DCs exhibited prolonged graft survival and improved function. Flow cytometry showed increased regulatory T cells and reduced Th1 and Th17 cells. WB indicated that cGAS regulates DC maturation via NF-κB signaling. In conclusion, suppressing cGAS in DCs inhibits their maturation, thereby enhancing graft survival.