Video 2.
Sub-lethal induction of pyroptosis on a single-cell level. Time-lapse fluorescence confocal microscopy showing HaCaT cells stably expressing optoCaspase-1 (red) that were transiently stimulated with the low dose of blue light at 3 min and left to recover for 1 h, after which a second round of 10 times more intensive light stimulation was performed. Inset (left) shows a cell displaying a sub-lethal membrane damage (as judged by the acquisition of low-intensity DRAQ7 staining, blue) after the first pulse. The cell transitions into “full” pyroptosis (gain of strong DRAQ7 signal, loss of cytosolic mCherry and membrane blebbing) after the second pulse of illumination. Scale bar, 20 µm.