Genes turn on, and genes turn off. Again and again, the genes that together comprise the human genome receive electrical signals that can direct when they should be active—and when they should be dormant. This intricate pattern of signals is a part of what guides an embryonic stem cell to grow and mature into any one of the many types of cells that make up the human body.
These electrical signals that guide cell growth have long been described as molecular ‘switches.’ But now, scientists at Tufts University have decoded these electrical signals—and discovered that they are far more complex than we had ever imagined.
Reporting in today’s issue of the Journal of Neuroscience, lead author Michael Levin and his Tufts research team have mapped the electrical signals transmitted between cells during development, and found that not only do these signals direct when a gene should be switched on, they also carry their own set of instructions, crucial to cellular development. Using the example of brain formation, Levin explained in today’s news release:
“We’ve found that cells communicate, even across long distances in the embryo, using bioelectrical signals, and they use this information to know where to form a brain and how big that brain should be. The signals are not just necessary for normal development; they are instructive.”
Instead of a molecular switchboard, an analogy that some have used to describe these bioelectrical signals, Levin likened the system to a computer. The signals themselves act like software programs, delivering instructions and information between cells at precisely the right time—even cells at great distance from one another.
Using tadpole embryos as a model, the team identified that the pattern of changes in voltage levels between cell membranes, called cellular resting potential, is the source of these bioelectrical signals, which are crucial to cellular development.
Specifically, the team mapped the changing voltage levels in embryonic stem cells in regards to the formation of the brain. In addition to discovering that these bioelectric signals instruct the formation of organs such as the brain, their discovery also hints at how scientists could manipulate these signals to repair tissues or organs that have been damaged—or even to grow new, healthy tissues.
“This latest research also demonstrated molecular techniques for ‘hijacking’ this bioelectric communication to force the body to make new brain tissue at other locations and to fix genetic defects that cause brain malformation,” Levin explained. “This means we may be able to induce growth of new brain tissue to address birth defects or injury, which is very exciting for regenerative medicine.”
In addition, the authors argue that modifying the bioelectrical signals to generate tissue—rather than modifying the genes themselves—may reduce the risk of adverse effects that may crop up by modifying genes directly.
While it’s early days for this work, Levin and his team foresee ways to apply this knowledge directly to medicine, for example by developing electricity-modulating drugs—which they call ‘electroceuticals’—that can repair damaged or defective tissue, and induce tissue growth.