X Wang and H-H Gerdes
It has previously been shown that cells have the ability to transfer mitochondria through the formation of tunnelling nanotubes (TNTs), which can extend from one cell to another. The authors use UV light to promote apoptosis in a culture of pheochromocytoma 12 cells, and show that cell death can be rescued through coculture with healthy cells. They show that after cytochrome-c release, but before caspase-3 activation, stressed cells extend microtubules out to healthy cells. The healthy cells then donate healthy mitochondria to the stressed cells, causing a reduction in cell death. Inhibition of TNT formation almost eliminates the ability of healthy cells in coculture to rescue cell death.