Nature: heavyweight! Reveal the mechanism of hair whitening caused by stress! Over activation of sympathetic nerve leads to exhaustion of pigment regeneration stem cells

January 27, 2020 / BIOON / - -- Marie Antoinette's hair turned white overnight when she was arrested during the French Revolution In recent history, John McCain was seriously wounded as a prisoner of war during the Vietnam War, and his hair lost color For a long time, anecdotes have linked stress experiences to hair bleaching Now, in a new study, researchers from Harvard University and other research institutions in the United States have for the first time found out exactly how this process works: stress activates nerves that are part of a fight or flight response, which then regenerates stem cells from pigment in hair follicles Cell) caused permanent damage The findings raise scientists' awareness of how stress affects the body The related research results were published online in the journal Nature on January 22, 2020, and the title of the paper is "hyperactivation of sympathetic nerves drives completion of melanicite stem cells" The corresponding author is Dr Ya Chieh Hsu, associate professor of stem cell and regenerative biology, Harvard University Picture from nature, 2020, DOI: 10.1038/s41586-020-1935-3 "Everyone has anecdotes about how stress affects their bodies, especially on their skin and hair - the only two types of tissue we can see from the outside," Hsu said We want to understand if this association is right, and if so, how stress can lead to changes in multiple organizations Besides hair pigmentation, an easy to touch and easy to handle process, we really want to know if stress really causes hair to turn white " To narrow down the culprit, given that stress affects the whole body, these researchers must first determine which body system is responsible for linking stress to hair color They first hypothesized that stress would lead to an immune attack on pigment producing cells But when mice lacking immune cells showed white hair, they turned to a hormone called cortisol But this is another dead end "Stress always increases cortisol levels in the body, so we think cortisol may play a role," Hsu said But surprisingly, when we remove the adrenals from mice so that they can't produce cortisol like hormones, their hair still turns white under pressure " After systematically eliminating the possibilities, the researchers focused on the sympathetic nervous system responsible for the body's fight or flight response The sympathetic nerve extends to every hair follicle on the skin The researchers found that stress causes the nerves to release the chemical noradrenaline, which is absorbed by nearby pigment generating stem cells Permanent damage in hair follicles, some stem cells act as a reservoir of pigment producing cells When hair regenerates, some stem cells turn into pigment producing cells that discolor the hair The researchers found that norepinephrine from the sympathetic nervous system causes these stem cells to over activate All of these stem cells turn into pigment producing cells, which prematurely deplete the stem cell repository "When we started looking at this, I thought stress was bad for the body, but we found that the bad effects of stress were beyond my imagination," Hsu said A few days later, all pigment derived stem cells were lost Once they're gone, you can't color them anymore The damage is permanent " The findings highlight the negative effects of an evolutionary response that was originally protective, the researchers said "Acute stress, especially fight or escape response, has traditionally been considered beneficial to animal survival," said Bing Zhang, the first author of the paper and a postdoctoral researcher at Harvard University However, in this case, acute stress can lead to permanent depletion of some stem cells " To answer a basic question about the relationship between stress and hair whitening, these researchers started from the whole body reaction, gradually narrowed down to various organ systems, cell-cell interactions, and finally molecular dynamics This process requires a variety of research tools, including methods to manipulate organ, nerve and cell receptors "In order to go from the highest level to the lowest level of detail, we work with many scientists in many disciplines to use a combination of different methods to solve a very basic biological problem," Zhang said The collaborators included Isaac Chiu, an assistant professor of immunology at Harvard Medical School, who studied the interaction between the nervous system and the immune system "We know that peripheral neurons can effectively regulate organ function, blood vessels and immune responses, but we don't know much about how they regulate stem cells," Chiu said Through this study, we now know that neurons can control stem cells and their functions, and can explain how they interact at the cellular and molecular levels, thereby linking stress to hair bleaching " These findings help to elucidate the broad effects of stress on various organs and tissues This understanding will pave the way for new research that seeks to change or stop the destructive effects of stress "By accurately understanding how stress affects pigment regeneration stem cells, we have laid the foundation for understanding how stress affects other tissues and organs of the body," Hsu said Understanding how our tissues change under stress is a key first step toward the ultimate treatment that can prevent or reverse the harmful effects of stress We still have a lot to learn in this field " (bio Com) reference: 1 Bing Zhang et al Hyperactivation of symbolic energies drives completion of melanicite stem cells Nature, 2020, DOI: 10.1038/s41586-020-1935-3 2 Solving a biological puzzle: how stress causes gray hair https://mediaexpress.com/news/2020-01-biological-puzzle-stress-gray-hair.html 3.how the stress of fight or flight turns hair white https://www.nature.com/articles/d41586-019-03949-8