WT1 and glomerulosclerosis: The mechanisms of sirolimus-associated glomerular injury are not yet fully delineated, but podocyte injury and glomerulosclerosis may be related to reduction of VEGF synthesis, AKT1 phosphorylation and expression of the transcription factor WT1 (required for maintaining podocyte integrity), the slit-diaphragm protein nephrin, and the cytoskeletal adaptor protein Nck, along with altered actin formation, leading to reduced podocyte adhesion and motility [57–59].