How Wounds Heal: Secrets to Healing Discovered in Zebrafish

When we hurt ourselves with scrapes and cuts, our bodies quickly respond to start the healing process. A crucial part of this wound healing includes the migration of nearby skin cells toward the center of the wound. Yet exactly how these cells "know" which way to migrate has long puzzled scientists. Now, researchers have discovered a signaling system that plays a huge role in wound healing and reveals further insights into the process of recovery.

In order to look a bit closer at the process of healing, the researchers conducted a study using zebrafish skin cells. These cells migrate much faster than human cells--mainly because they have to.

"Fish have to heal quickly," said Mark Messerli, one of the researchers, in a news release. "They are surrounded by microbes and fungi in the water. They are constantly losing scales, which generates a wound. So the wound has to be healed in the epidermis first and then a new scale has to be built. Fish skin cells (keratinocytes) migrate five times faster at room temperature than mammalian cells do at 37 degrees C. So it is very easy to track and follow their migratory paths in a short period of time."

At the start of the study, the researchers examined calcium signaling at the single-cell level, which is who this signaling has been looked at for decades. But how do these single cells actually "see" injury? The researchers used advanced microscopy to monitor cellular calcium signals and molecular analysis to identify membrane proteins that caused increases in cellular calcium migration. By the end, the researchers found they were looking at the calcium signals not just in single cells but in sheets of cells that surround wounds. In addition, the scientists found that TRPV1, the ion channel that is also activated in hot peppers, is necessary for migration.

"The periphery of the wound itself appears to form a graded calcium signal that could direct migration and growth toward the center of the wound," said Messerli. "This is what we are looking at now."

The findings reveal a little bit more about how exactly wounds heal. In addition, they could be important for encouraging the healing process and developing new treatments in the future.

The findings are published in the Journal of Cell Science.