“It was a very evident, active signal” that strongly resembled a neuron’s self-generated electrical spikes, Yu says. These bursts were faster than chemical messengers but much slower than neurons’ signals; they lasted seconds instead of milliseconds and rippled across at least a dozen other epithelial cells. It is unclear how the epithelial cells produced the signals, but the researchers found that these cells could fire only in the presence of calcium ions. Neuron signaling is also known to rely on ions, including calcium, sodium and potassium; the ions’ electrical charge provides the signature voltage spike.
The new observations “show that maybe there’s longer-range communication” among epithelial cells to coordinate healing, Foxman says. Understanding exactly how these cells respond to damage could reveal why the process sometimes goes wrong. “When you get a cut, sometimes it heals perfectly,” she says, but other times the process leaves a scar—and scars on an internal organ’s epithelium can sometimes lead to chronic health conditions. “That’s what I’m excited about,” Foxman adds. “Whenever you find a new pathway, you could study and potentially use [it] to develop a new treatment.”
It’s still not certain what role this signaling plays in living organisms or what other cells do when they receive a signal, says Sarah Najjar, who studies gut epithelial cells at New York University. “What is downstream of this electrical activity?” she wonders. Does it influence neurons? Yu next plans to study whether these two types of cells interact. “I want to know how the high-pitched signals [of neurons] are translated” for epithelial cells tuned to lower-pitch signals, and vice versa, she says. “It’s a study coming from our curiosity.” {read}