Abstract
Inflammation induced by autoreactive CD4+ T lymphocytes is a major factor in the pathogenesis of multiple sclerosis (MS). Immunosuppressive drugs, such as FTY720, are subsequently developed to prevent the migration of CD4+ T lymphocytes to the central nervous system (CNS). However, these immunosuppressive drugs have limited accumulation in lymph nodes (LNs), resulting in poor efficacy. Here, this work develops a nanoplatform for delivering immunosuppressive drugs to LNs for durable MS treatment. Human CD47 peptide and L-selectin targeting aptamer are modified on the nanoparticles encapsulated with FTY720 (clnFTY) for self-passivation and the targeting of L-selectin on lymphocytes, a homing receptor for T-cells entering LNs. Using this natural process, clnFTY nanoparticles efficiently deliver FTY720 to LNs and delay disease progression in experimental autoimmune encephalomyelitis (EAE) mice following a single dose treatment over a 42-day observational period. Considering the daily dosing requirement of FTY720, this strategy greatly improves its therapeutic efficiency. The ability of clnFTY nanoparticles to target lymphocytes, reduce sphingosine-1-phosphate receptor 1 (S1PR1) expression, and suppress inflammatory cytokines release are demonstrated in clinical blood samples from MS patients. Taken together, this study demonstrates that targeted LNs delivery may greatly extend the treatment cycle of immunosuppressive drugs for durable MS treatment.