Interleukin-7 stimulation inhibits nephrin activation and induces podocyte injury.

The glomerular podocytes control filtration barrier permeability in the kidney, and their disturbance underlies the pathogenesis of idiopathic nephrotic syndrome (INS), a kidney disease that predominantly occurs in children. In this study, we found that the interleukin-7 receptor (IL-7R) was induced in the glomeruli of adriamycin (ADR)-induced mouse nephropathy, a rodent model of nephrotic syndrome. In addition, IL-7R was also induced by ADR in mouse podocytes cultured in vitro. Functionally, we discovered that IL-7R activation through the stimulation of recombinant IL-7 induced apoptosis of podocytes, and moreover, IL-7 stimulation inhibited nephrin activation and caused actin cytoskeleton disorganization, indicating that IL-7 stimulation induces podocyte injury. Furthermore, IL-7 stimulation impaired the filtration barrier function of podocyte monolayer. Together, these results identify IL-7 and its receptor IL-7R as potential regulators of podocyte function, which might offer a novel therapeutic target in the treatment of INS.