Fig. 3.

CsA suppresses β3 integrin activation, but not its cell surface expression. Double immunofluorescence staining for active β3 integrin (red) and the podocyte marker synaptopodin (synpo, green) in glomeruli from NTX rats (a) and LPS mice (b) treated with or without CsA, as evaluated by confocal microscopy. AP5 antibody was used to detect active β3 integrin since the binding ability of AP5 to active β3 integrin has been tested [4, 24]. AP5 labeling was strongly induced in podocytes form untreated NTX rats (a) or LPS mice (b). When treated with CsA, NTX rats (a) or LPS mice (b) showed a substantial reduction of AP5 labeling in podocytes. However, the total expression of β3 integrin (red) remained unchanged in glomeruli from NTX rats (c) and LPS mice (d) treated with or without CsA. (e) Flow cytometry for the AP5 antibody binding to cultured differentiated podocytes showed a high activated β3 integrin population after LPS treatment. CsA (0.25–1 μg/ml) reduced the activation of β3 integrin (p<0.01). However, the total expression of β3 integrin protein (f) and mRNA (g) was unresponsive to LPS or CsA treatment (p>0.05). All values are expressed as the means±SD. *p<0.01 versus podocytes treated with LPS only