MSC mitochondria (red) approach damaged cells (blue), whose division (bottom) indicates aerobic rescue.
PROCKOP/NAS
Prockop's group stumbled across this remarkable ability while studying bone marrow stem cells (MSCs), which were particularly social in culture, often touching each other and then backing off. Small numbers of MSCs can repair some damaged heart cells, whose main defect is usually a loss of mitochondrial activity. The authors thus wondered whether the contact behavior allowed MSCs to transfer mitochondria. “It was a way out-there hypothesis,” says Prockop, “that we wouldn't have mentioned to anyone had the experiment not worked out.”
To test their “out-there” idea, the group damaged the mitochondrial genome (mtDNA) of a transformed epithelial cell line using ethidium bromide and then looked for...
