Image: Martin Picard
Mitochondria have shelflike internal membrane folds called cristae. Picard’s research group observed that when mitochondria touch, their cristae can line up on either side of the membrane.
During his doctoral research on the ties between aging and mitochondria, Martin Picard frequently saw micrographs of those energy-producing organelles. Yet it wasn’t until fairly late in his graduate work that he first watched sped-up video of mitochondria moving inside live human cells, and the sight came as a revelation.
Tagged with fluorescent dye, the mitochondria were neon squiggles crawling through the soupy interior of the cells — stretching and contracting, fusing together and splitting up again, sidling up to one another and parting ways. Their apparent eagerness to network reminded Picard of the social exchanges among complex creatures like fish and ants. “They just look a little more primitive,” he said.
Now, after years of work in his own laboratory and others that has underscored the importance of those dynamic mitochondrial interactions, he is pressing that comparison more literally. Recently, in Neuroscience & Biobehavioral Reviews, Picard, a mitochondrial psychobiologist at Columbia University, and the neuroscientist Carmen Sandi of the Swiss Federal Institute of Technology Lausanne argued that mitochondria need to be understood as the first known social organelles.
As evidence, they cite a long line of discoveries showing that mitochondria are surprisingly interdependent and that their functions go far beyond their familiar role as cellular powerhouses: Mitochondria also make certain types of hormones, help drive immune responses, and shape the developmental fate of cells. To these diverse ends, like ants in a colony, mitochondria divide up tasks, form groups, synchronize activities and respond to both their environment and each other. A “social lens,” Picard and Sandi wrote, may be essential not only for explaining the behavior of individual mitochondria, but for revealing the mitochondrial collectives that influence human health.
Despite some reservations about the label “social,” other scientists generally agree that understanding the bustling signaling networks that mitochondria establish within and between cells could help unlock secrets about health and disease. “If we understand how the mitochondria are acting together, and we learn how to manipulate it,” said James Eberwine, a molecular neurobiologist at the University of Pennsylvania, “we’re going to gain so much more insight into biology.”
Read the whole story in Quanta Magazine