Host-derived mannose glycans trigger a pathogenic?6 T cell/IL-17a axis in autoimmunity

Autoimmune diseases are life-threatening disorders that cause increasing disability over time. Systemic lupus erythematosus (SLE) and other autoimmune diseases arise when immune stimuli override mechanisms of selftolerance. Accumulating evidence has demonstrated that protein glycosylation is substantially altered in autoimmune disease development, but the mechanisms by which glycans trigger these autoreactive immune responses are still largely unclear. In this study, we found that presence of microbial-associated mannose structures at the surface of the kidney triggers the recognition of DC-SIGN-expressing gamma 6 T cells, inducing a pathogenic interleukin-17a (IL-17a)-mediated autoimmune response. Mice lacking Mgat5, which have a higher abundance of mannose structures in the kidney, displayed increased gamma 6 T cell infiltration into the kidney that was associated with spontaneous development of lupus in older mice. N-acetylglucosamine supplementation, which promoted biosynthesis of tolerogenic branched N-glycans in the kidney, was found to inhibit gamma 6 T cell infiltration and control disease development. Together, this work reveals a mannose-gamma 6 T cell-IL-17a axis in SLE immunopathogenesis and highlights glycometabolic reprogramming as a therapeutic strategy for autoimmune disease treatment.

Automated summary

Autoimmune diseases, such as systemic lupus erythematosus (SLE), are life-threatening disorders that progressively cause disability. This study found that the presence of microbial-associated mannose structures on the kidney surface triggers a pathogenic autoimmune response mediated by IL-17a, induced by DC-SIGN-expressing gamma 6 T cells. Mice lacking Mgat5, which have more mannose structures in the kidney, displayed spontaneous development of lupus with increased infiltration of gamma 6 T cells. N-acetylglucosamine supplementation inhibited gamma 6 T cell infiltration and controlled disease development, highlighting glycometabolic reprogramming as a potential therapeutic strategy for autoimmune diseases.