As white blood cells die, they send out signals to fellow leukocytes nearby—possibly to alert them that they’ve been attacked by a pathogen, and are in the throes of death.
Using time-lapse microscopy, scientists at La Trobe University were able to film this process for the first time. In the past, most of what they’d gleaned about white blood cell death (called apoptosis) came from observing cells that had already died. Now, experts have a window into the specific stages that guide leukocyte death; from that information, cell biologists may be able to infer more about how pathogens annihilate cells and spread disease. The team also learned that the nature of white blood cell death is far from what we thought it was.
Here’s Melissa Davy, writing for The Guardian:
Until now, scientists believed cells died and fell apart in a random process. The time-lapse “video”, however, shows their death is highly controlled and deliberate. The findings were published in the prestigious international medical journal, Nature Communications, on Monday.
Cell biologist Georgia Atkin-Smith was co-leader of the team to capture the process, which she said shows cell death comprised three stages; bulging, exploding and breaking apart.
“So when the cell starts to die it forms these lumps which push outwards and when the cell then explodes, it shoots out long ‘beaded’ protrusions which look like a necklace, which then breaks apart into individual ‘beads’,” she said.
These protrusions have been deemed “beaded apoptopodia.” The team believes that some molecules in the beads may contain a chemical warning that, when eaten by a live cell, can tip off other white blood cells around that a pathogen—a virus or infection—is looming close by.
Watch this white blood cell die and shoot out a 'beads-on-a-string' membrane structure:
Atkin-Smith and her team have discovered drugs—notably, sertraline (an antidepressant)—that can manipulate this process, so the hope is that they’ll be able to modify the body’s healing mechanisms as a result of this work. And someday, that could lead to dramatic changes in the way we build up the body’s defenses against external threats.
Photo credit: La Trobe University