BETA-1 INTEGRINS IN THE NORMAL HUMAN GLOMERULAR CAPILLARY WALL - AN IMMUNOELECTRON MICROSCOPY STUDY

The localization of the alpha(2), alpha(3) and alpha(6) subunits of th e beta(1) integrin family on different cells of the glomerular capilla ry wall and on juxtacapillary mesangium was investigated using an immu noelectron microscopic technique on freshly harvested normal human glo meruli. alpha(2) beta(1), alpha(3) beta(1) and alpha(6) beta(1) were w eakly expressed on both luminal and abluminal surfaces of glomerular e ndothelial cells; alpha(2) beta(1) and alpha(3) beta(1) were also foun d on the mesangium of the juxtacapillary areas. alpha(3) beta(1) was r egularly present in great density on the basal and lateral surface of podocyte foot processes, confirming alpha(3) beta(1) as the unique bet a(1) integrin on glomerular epithelial cells. None of these integrins was strictly polarized along the glomerular basement membrane, thus su ggesting, in agreement with recent literature, that these molecules pe rform other biological functions in addition to adhesivity.