Figure 1.

Rescue of UV-treated PC12 cells in cocultures. (a) The level of cell death of UV-treated cells decreased in coculture condition. CTB-labelled PC12 cells were treated with UV light and grown in monoculture or in coculture with untreated cells for 24 h. The percentage of dead cells was quantified by staining with annexin V-AF488. UV-treated cells were also incubated for 24 h in the presence of 80 μM Z-VAD-FMK or in conditioned medium from untreated cells as indicated. (b) TNTs (arrows) were formed between CTG-labelled (CTG, green) and -unlabelled cells in control and UV treatment conditions but not in the presence of 350 nM cytoB (UV+cytoB). The cocultures were stained with WGA-AF594 (WGA, red) and imaged by confocal microscope. Scale bars, 20 μm. (c) Three hundred and fifty nanomolar cytoB abolished the formation of TNTs. The number of TNT between CTG-labelled cells (green circles), CTG-unlabelled cells (white circles) or CTG-labelled and -unlabelled cells were counted in the conditions as in (b). (d) Three hundred and fifty nanomolar cytoB inhibited the rescue effect. CTB-labelled cells treated with UV were cocultured with untreated cells (unlabelled) in the absence or presence of 350 nM cytoB for 24 h. The percentage of dead cells in both cell populations was quantified. NS, not significant; *P<0.05; **P<0.01