Cadherin and catenin staining in podocytes in development and puromycin aminonucleoside nephrosis

Podocytes have been shown to express classical cadherins in the early stage of glomerulogenesis, but it remains unclear whether podocytes in normal and pathological conditions express cadherins in the adult stage. To address this question, rat podocytes in the neonate, the adult and in puromycin aminonucleoside (PAN) nephrosis were examined by immunofluorescence microscopy using antibodies against alpha- and beta-catenins and anti-pan-cadherin antibody, and by immunoelectron microscopy using anti-alpha-catenin antibody. In the neonate, all the antibodies reacted with the junctional complex of podocytes in the S-shaped body stage. The staining disappeared during the capillary loop stage, when foot processes and slit diaphragms are formed. In the adult, podocytes were not stained with any of the antibodies, whereas distinct staining with the antibodies was detected in endothelial cells and mesangial cells in the glomerulus. These findings were identical in kidneys of PAN nephrosis; podocytes did not show any significant staining. These results indicate that the composition of intercellular junction molecules of podocytes in the adult is different from that of immature podocytes even under the pathological condition.