Nanogel-based delivery of mycophenolic acid ameliorates systemic lupus erythematosus in mice

The ability to selectively inactivate immune cells with immunosuppressants is a much sought-after modality for the treatment of systemic lupus erythematosus and autoimmunity in general. Here, we designed and tested a novel nanogel drug delivery vehicle for the immunosuppressant mycophenolic acid (MPA). Treatment with MPA-loaded nanogels increased the median survival time (MST) of lupus-prone NZB/W F1 mice by 3 months with prophylactic use (MST was 50 weeks versus 38 weeks without treatment), and by 2 months when administered after the development of severe renal damage (MST after proteinuria onset was 12.5 weeks versus 4 weeks without treatment). Equivalent and greater doses of MPA administered in buffer were not efficacious. Nanogels had enhanced biodistribution to organs and association with immune cells. CD4-targeted nanogels yielded similar therapeutic results compared with nontargeted formulations, with protection from glomerulonephritis and decreases in IFN-gamma-positive CD4 T cells. DCs that internalized nanogels helped mediate immunosuppression, as they had reduced production of inflammatory cytokines such as IFN-gamma and IL-12. Our results demonstrate efficacy of nanogel-based lupus therapy and implicate a mechanism by which immunosuppression is enhanced, in part, by the targeting of antigen-presenting cells.