Posted on May 14, 2018, 1 p.m.
Loss of hair pigmentation, going gray, has been associated with activation of innate immune system and viral infection, in response to serious illness or chronic stress. Researchers claim to have been able to discover connections between genes which contribute to hair colour and genes which notify bodies of pathogenic infection, as published in the journal PLOS Biology.
The innate immune system kicks into high gear when the body is under attack from bacteria or infection. All cells have ability to detect foreign invaders and respond by producing signaling interferon molecules to signal other cells to take action via turning on gene expression which inhibits viral replication, increasing host defenses, and activates immune effector cells.
Connection between the innate immune system and hair pigmentation came a bit of a surprise, but genomic tools allow access to how genes within the genome change expression under different conditions often show changes in ways that are not always anticipated. Interest in genes which affect stem cells over time is important, gray hair is an easy read out of melanocyte stem cell dysfunction. Melanocyte stem cells produce the melanocytes which are required for making and depositing pigment into hair shafts.
Transcription factor MITF has a role in regulating melanocytes many functions, and it was found that MITF also serves to keep melanocytes interferon responses in check; if the control of the interferon response was lost in melanocyte stem cells the result is hair graying. Should innate immune signalling become artificially activated increased numbers of gray hair were also observed to be produced by the researchers.
Findings suggests that genes which control pigment in skin and hair also work to control the innate immune system, which may help to enhance understandings of gray hair, and with conditions such as Vitiligo. Why mice predisposed to gray hair were more susceptible to dysregulation of innate immune signalling was not answered, studies will continue to investigate and address the question.
Materials provided by PLOS.
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Melissa L. Harris, Temesgen D. Fufa, Joseph W. Palmer, Sandeep S. Joshi, Denise M. Larson, Arturo Incao, Derek E. Gildea, Niraj S. Trivedi, Autumne N. Lee, Chi-Ping Day, Helen T. Michael, Thomas J. Hornyak, Glenn Merlino, William J. Pavan. A direct link between MITF, innate immunity, and hair graying. PLOS Biology, 2018; 16 (5): e2003648 DOI: 10.1371/journal.pbio.2003648