New research has identified a potential way to reverse graying hair and treat skin pigment disorders. By studying stem cells in mice, scientists at NYU Langone Medical Center in New York City have found the molecular pathways responsible for creating the color of skin and hair.
Their findings, published April 28 in Cell Reports, could one day lead to cosmetic treatments that restore graying locks to more youthful colors such as brown, blond and red. The research may also be useful for developing drug candidates for people with vitiligo, a disease that causes skin to lose its color and leads to blotchy white patches. Vitiligo—which affects 2 million to 5 million people in the U.S. and 50 million people worldwide, according to the National Vitiligo Foundation—also causes pigment loss in mucous membranes of the mouth, nose and eyes.
The researchers conducted a series of experiments on stem cells, all part of the same study to investigate the biological process at work in pigmentation. They found that a certain signaling pathway—known as Edn/EdnrB—interacts with other pathways, in particular the Wnt signaling pathways, which in turn causes the proliferation of melanocyte, stem cells involved in the earliest stage of skin and hair pigmentation. In previous research, these pathways have been identified for their role in controlling blood vessel development. They’re also partially responsible for cell growth and division. But this is the first time that these specific signaling processes have been linked to hair and skin color.
As part of their investigation, the researchers bred mice that were EdnrB pathway–deficient and discovered that their fur grayed prematurely. Later experiments involved doing the opposite: engineering the mice to amp up the function of the same pathway, which led to a 15-fold increase in melanocyte production, which caused hyperpigmentation in the mice. The researchers made small wounds on the animals and noticed the skin was much darker when it began to heal. This suggests creating a drug that targets this pathway may eventually lead to better ways to treat the discoloration that occurs around scars.
In one experiment that may have an impact on the cosmetics industry, the team of researchers blocked the Wnt signaling in mice, which slowed melanocyte growth and resulted in unpigmented gray hair. This finding suggests that targeting the Wnt pathway may be one way to reverse gray hair.
The industry has long sought alternatives to hair color in a bottle. Many people are allergic to the dyes and cosmetics currently on the market. Those who do regularly turn to dye bemoan the time and money it requires and also the damage it causes to hair. But science appears to be on the way to identifying potential solutions simply by gaining a better understanding of the biology behind the graying process.
In March, Nature Communications published findings from a different study, led by researchers at University College London, who identified the primary gene responsible for gray hair. That gene is tasked with regulating and producing melanin, the pigment that gives hair color. And scientists could potentially develop drugs that target particular pathways linked to the gene.