Figure 6.

PI Intake but Not Early Calcium Signal Is Mediated by Membrane Pores

(A) Impermeant intracellular molecules impose an osmotic gradient after pore opening that leads to net influx of water molecules and cell lysis.

(B) PEGs can prevent this effect if their size is large enough to not cross the membrane through the pores.

(C) Calcium flux and PI intake in NIH 3T3 cells treated with TSZ in the presence or absence of PEG 8000. Scale bar, 50 μm.

(D) Kinetics of calcium flux,

(E and F) Change in cell shape (E) and PI intake (F) in NIH 3T3 cells in the presence of PEGs of different sizes.

(G) PI and Fluo-4/Ca-positive NIH 3T3 cells after TZ induction in the presence or not of PEG 8000.

(H) Kinetics of PI intake in individual NIH 3T3 cells. 20 individual cells were selected, and the fluorescence intensity of the PI was recorded every 5 s. Values were normalized taking as 100% the maximum of the fluorescence obtained per cell.

(I) Time lapse of PI intake, calcium flux, and membrane breakdown. Scale bar, 10 μm.

(J) FD10 influx in NIH 3T3 cells after treatment with TSZ. First-line scale bar, 20 μm, second-, third-, and fourth-line scale bars, 10 μm.

(K–M) Kinetics of PI influx in L929 cells treated with (K) TZ, (L) PZ (IFN primed), or (M) LZ in the presence or not of PEGs.

Results show the mean and the SD from at least three independent experiments. Error bars represent SD from the measurements. Lines correspond to the best fitting of the data.