Wounds are healed by themselves, but some fail to heal and become chronic. A team of international researchers led from Karolinska Institutet, have discovered the role of microRNAs in regulating skin wound healing. The discovery could lead to therapeutic possibilities for the treatment of chronic wounds.
About 0.2 to 1 percent of the population in the developed countries are affected by chronic wounds. As of today, treatments focus on ways to clear infections. But there is an important need to have direct impact on the wound healing process, which led the researchers to find therapeutic targets for chronic wounds.
Would healing is a complex process. In the inflammatory phase, damaged and dead cells, bacteria and debris are cleared out by immune cells. In the following proliferative phase, skin cells multiply to grow as new tissue. The transition between these two regulatory point determines the outcome of healing process.
MicroRNAs, or miRNAs, are short pieces of genetic code that are involved in a range of diseases.
"There is very little known about the expression and function of miRNAs in human skin wounds, but we have previously shown that miRNAs play important roles in the regulation of the cells in the outermost layer of the skin, also called keratinocytes", says Dr. Ning Xu Landén, principal investigator at the department of medicine, Solna, Karolinska Institutet.
The researchers collected skin biopsies from the edge of wounds, and looked for changes in miRNA expression during the healing process. They found miR-132, its expression increased during the inflammatory phase and then peaked again in the proliferative phase.
In the inflammatory phase, miR-132 caused less immune cells to move to the wound, whereas a lack of miR-132 meant more immune cells and hence increased inflammation. During the proliferative phase, miR-132 promoted keratinocyte growth, while a lack of miR-132 decreased cell growth and wounds took longer to heal.
"Our results show that miR-132 is important during the transition from the inflammatory to the proliferative phase and therefore acts as a critical regulator of skin wound healing. Due to its pro-healing capacity, miR-132 may be an attractive therapeutic target for chronic skin wounds. Our goal is to develop a microRNA-based treatment to promote healing,"said Xu Landén.
The study is published in the Journal of Clinical Investigation.