FIGURE 8.

Intercellular interactions between preconditioned and non-preconditioned NRK cells prevent SG formation after hypertonic shock in non-preconditioned cells. A, GFP-YB1-transfected NRK cells were loaded onto layers of control or preconditioned NRK cells. Preconditioned cells were returned to isotonic conditions just before the addition of transfected cells. After 4 h, to let the transfected cells incorporate the cell layers, cells were exposed to hypertonic shock (720 mosmol/kg for 45 min) and fixed. GFP fluorescence was used to distinguish transfected cells and anti-YB-1 immunostaining for the detection of SGs in all cells. Isolated transfected cells (control) or transfected cells that had incorporated a non-preconditioned monolayer of cells displayed typical SGs. On the other hand, for transfected cells incorporated into a preconditioned layer, cell-cell interactions led to the inhibition of SG assembly. Scale bar, 10 μm. B, conditions were the same as A with a preconditioned cell layer. Transfected cells not yet fully incorporated in the monolayer of cells or when treated with oleamide, a gap junction inhibitor (50 μm for the 4 h required for transfected cells to incorporate the cell monolayer), displayed large SGs, whereas the assembly of SGs was inhibited in the preconditioned cell monolayer. Scale bar, 10 μm. C, statistical analysis of the SG areas after the treatments indicated in A and B. Results are the means ±S.D.