Cells are swapping their mitochondria. What does this mean for our health?

Summary

There’s unexpected movement in the world of cell biology — specifically, with the energy factories known as mitochondria.Ever since they were discovered in the mid-nineteenth century, mitochondria have been known as organelles that reside inside cells. But that textbook picture now seems to be wrong. An explosion of research is challenging mitochondria’s long-standing image as exclusively cellular organelles. “They may be a multicellular organelle,” says Jonathan Brestoff, an immunologist who studies metabolism at Washington University in St. Louis, Missouri. In other words, the supposedly static energy factories now seem to be expert travellers, skipping from one cell to another on demand.Cancer cells ‘poison’ the immune system with tainted mitochondriaThis ‘mitochondrial transfer’ has been observed in a wide variety of cells and in organisms as diverse as yeast, molluscs and rodents. “It’s really exciting to see,” says Jeffrey Spees, a stem-cell biologist at the University of Vermont in Burlington.It’s not yet clear why mitochondria are so mobile. Some studies have hinted that cells donate their mitochondria to their neighbours during times of need. In cellular emergencies, newly arrived mitochondria might kick-start tissue repair, fire up the immune system or rescue distressed cells from death. Other research suggests that mitochondrial transfer can be a lethal weapon that cancer cells deploy to gain an advantage.But what this means for human health is still a mystery. Researchers haven’t yet captured the process inside the human body and so don’t know for sure if it happens in people, says Daniel Davis, an immunologist at Imperial College London. “We don’t have the technology yet to witness this happening,” he says.That fact hasn’t stopped researchers from exploring how to leverage mitochondrial transfer to treat a variety of diseases, including cancer and stroke.A borrowed bacteriumOver the past three decades, research has revealed that mitochondria are much mo...