Researchers in Germany report a major finding in the field of neuroscience that could have important ramifications in new pain therapies targeting Schwann cells in the skin. Classical understanding of the nervous system dictates that neurons detect and transmit sensory data to and from the brain. The neuroglia is the support system that protects, insulates, and provides nutrients to neurons. Schwann cells are a type of neuroglia that maintain and protect neurons in the peripheral nervous system, including those directly under the skin.
If questioned, most scientists would agree that sensory detection happens exclusively by neurons in the peripheral nervous system, including in the Meissner’s corpuscles. However, recent studies have identified nociceptive (pain sensing) functions in some Schwann cells. Scientists had previously thought that sensory neurons alone were responsible for detecting sensory information, such as touch and vibrations, under the skin. However, it turns out that Schwann cells also play a vital role in sensory touch perception, according to researchers who published a study, “Sensory Schwann cells set perceptual thresholds for touch and selectively regulate mechanical nociception” in Nature Communications this week.
“We were surprised at the extent to which the Schwann cells participate in stimulus detection,” said Gary Lewin, PhD, head of the molecular physiology of somatic sensation lab at the Max Delbrück Center. The study’s international team conducted experiments in mice using optogenetics. Mice were bred with Schwann cells that were modified to turn on and off when exposed to different wavelengths of light. These mice were trained to sense and identify tiny vibrations with their paws, so when they were exposed to different lights, turning off Schwann cells, scientists could determine if the mice were sensing the vibrations. When Schwann cell function returned, so did the mice’s ability to detect vibrations.
The team was further able to identify differences in sensory input from Schwann cells using optogenetics, revealing that mechanical stimuli, including vibrations, were detected by the cells but temperature stimuli were not. “It may be that polymodal nociceptors, which react to mechanical, thermal, and chemical stimuli, only function properly with the help of Schwann cells,” said Lewin.
“The Schwann cells just below the surface of the skin are easily accessible to therapeutic agents,” said Lewin. “This makes them an attractive target for tackling the problem right at the root.” These results further confirm the diverse function of Schwann cells and have opened up many more avenues of research for understanding the intricacies of the nervous system. Further continued research will aid in developing more effective treatments and interventions for pain management, bringing us closer to addressing touch and pain disorders with greater precision and efficacy.
