The immune system might have something to do with why people’s hair turns gray when dealing with stress or illness, a new study says.
Melanocytes are the cells that make up melanin and give hair its color, Newsweek reports. Specialized stem cells add melanocytes to new follicles when hair falls out, and when these stem cells don’t work, hair loses its color.
Scientists at the National Institutes of Health and the University of Alabama, Birmingham, set out to examine this process and its relationship with the body’s immune system, doing so on mice.
The human immune system forms the line of defense against viruses and bacteria, triggering cells under attack from foreign objects to produce signaling molecules called interferons. Interferons dictate to other cells when to turn on the gene expression that keeps viruses from replicating, and prompting immune effector cells to protect the body.
The authors of the study looked at how the immune system’s response to attacks affects the MITF protein, which in turn helps melanocytes function. They discovered that when MITF has no control over interferon responses in melanocyte stem cells, hair can become gray. In addition, mice that are genetically predisposed to having gray hair developed this response when the immune activity was turned on artificially.
Further studies are needed to understand what causes these reactions, and see if the same things happen in people, too.
Melissa Harris, the lead author of the study and assistant professor at the department of biology at UAB, said, “Genomic tools allow us to assess how all of the genes within our genome change their expression under different conditions, and sometimes they change in ways that we don’t anticipate.” She added,
We are interested in genes that affect how our stem cells are maintained over time. We like to study gray hair because it’s an easy read-out of melanocyte stem cell dysfunction.
The researchers hope this can offer a better understanding into diseases that affect pigmentation, such as vitiligo, which destroys pigment cells.
The study was published in PLOS Biology.