Redistribution of integrins in tubular epithelial cells during diabetic glycogen nephrosis

Background/Aims: Even though many aspects of glycogen nephrosis in diabetes have already been studied, adhesion interactions between the glycogen-accumulating clear cells and the tubular basement membranes have not been addressed. As integrins play key roles in cell-to-matrix interactions, we investigated the expression and distribution of alpha(3)-, alpha(V)-, beta(1)- and beta(3)-integrin subunits in renal tissues from streptozotocin-induced hyperglycemic rats ( 3 months old) and their age-matched controls as well as from streptozotocin-injected normoglycemic animals. Methods: The levels and distribution of integrins were studied by immunocytochemistry and Western blot analysis. Results: Immunoblotting analysis of fractions enriched in glycogen-accumulating clear cells demonstrated enhanced expression of alpha(3), alpha(V) and beta(1) subunits while expression of 3 did not differ from controls. The most striking cytochemical result was the redistribution of the alpha(3)-, alpha(V)-, and the beta(1)-integrin subunits to the apical plasma membrane of these cells. This was found by light and electron microscopy. Conclusion: Our results suggest that the altered expression and distribution of integrins in clear cells of diabetic animals must have defined roles in the development of the renal tubulopathy. Copyright (C) 2004 S. Karger AG, Basel.