Macrophage anti-viral responses to diabetogenic Coxsackie virus infections are mediated by free radicals (BA6P.134)

Abstract

Abstract Reactive oxygen species (ROS) induces Type-1 diabetes (T1D) by directly killing pancreatic β-cells, triggering pro-inflammatory cytokine production, and promoting autoreactive T cell maturation. We hypothesize that free radical synthesis in T1D can synergize and enhance autoimmune responses in T1D onset and progression. Free radicals can be identified by immuno-spin trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and utilizing a DMPO-specific antibody to detect DMPO-radical adducts. We previously reported a delay in spontaneous T1D onset in Non-obese diabetic (NOD) mice impaired in NADPH Oxidase (NOX)-derived superoxide synthesis (NOD.Ncf1m1J). Bone marrow-derived macrophages (BM-Mϕ) from NOD.Ncf1m1J mice infected with Coxsackie virus CB3 strain displayed a significant decrease (p<0.0001) in fluorescence intensity of DMPO adducts at 4, 6,12 and 24 hours post-infection concomitant with a decrease (p=0.0027) in STAT1 phosphorylation compared to NOD BM-Mϕ. CB3 infected-NOD.Ncf1m1J BM-Mϕ also exhibited a decrease in Tnfa (p=0.0037) and Ifih1 (p=0.002) mRNA accumulation in contrast with NOD BM-Mϕ. These findings suggest that anti-viral responses in NOD.Ncf1m1J BM-Mϕ are redox-regulated and were compromised by ROS-deficiency. Our results further illustrate the importance of NOX-derived superoxide in modulating autoimmune responses in T1D. Future studies will utilize immuno-spin trapping to visualize the interface between free radicals and immune cells during T1D progression.