Flt3 inhibition alleviates chronic kidney disease by suppressing CD103+ dendritic cell-mediated T cell activation.

BACKGROUND: Chronic kidney disease (CKD) is a global public health problem, which lacks effective treatment. Previously, we have shown that CD103+ dendritic cells (DCs) are pathogenic in adriamycin nephropathy (AN), a model of human focal segmental glomerulosclerosis (FSGS). Fms-like tyrosine kinase 3 (Flt3) is a receptor that is expressed with high specificity on tissue resident CD103+ DCs. METHODS: To test the effect on CD103+ DCs and kidney injury of inhibition of Flt3, we used a selective Flt3 inhibitor (AC220) to treat mice with AN. RESULTS: Human CD141+ DCs, homologous to murine CD103+ DCs, were significantly increased in patients with FSGS. The number of kidney CD103+ DCs, but not CD103- DCs or plasmacytoid DCs, was significantly decreased in AN mice after AC220 administration. Treatment with AC220 significantly improved kidney function and reduced kidney injury and fibrosis in AN mice. AC220-treated AN mice had decreased levels of inflammatory cytokines and chemokines, tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, CCL2 and CCL5 and reduced kidney infiltration of CD4 T cells and CD8 T cells. The protective effect of AC220 was associated with its suppression of CD103+ DCs-mediated CD8 T cell proliferation and activation in AN mice. CONCLUSION: Flt3 inhibitor AC220 effectively reduced kidney injury in AN mice, suggesting that this inhibitor might be a useful pharmaceutical agent to treat CKD.