Genotoxic stress, namely anything that damages the genetic code of life DNA, causes a malfunction of the cells ultimately responsible for hair colour.
Going grey can be distinguished.
The stress sets off a chain of reactions involving specialised cells called melanocyte stem cells, their work on mice in Cell journal reveals.
Similar mechanisms appear to be at work in humans too, they say.
The findings could help explain why people with Ataxia telangiectasia, a rare, neurodegenerative syndrome caused by a mutation in a gene called ATM, go grey prematurely.
In their study, Dr Emi Nishimura and colleagues found the ATM "caretaker" gene serves as a checks and measures system to stop melanocyte stem cells going awry.
It is the job of these cells within the hair follicles to make the mature pigment-producing melanocytes that give hair its youthful colour.
Damaged DNA
Researchers have already traced greying to the gradual dying off of the stem cells.
But this is not the only way the stem cells are depleted.
They also progressively make errors, turning or differentiating into fully committed pigment cells in the wrong place within the hair follicle, where they are useless for colouring hair.
And the latest work on mice shows irreparable DNA damage, as caused by ultraviolet light and ionising radiation, is responsible.
Dr Nishimura of Kanazawa University said: "Once stem cells are damaged irreversibly, the damaged stem cells need to be eliminated to maintain the quality of the stem cell pool.
"We found that excessive genotoxic stress triggers differentiation of melanocyte stem cells."
But others believe going grey is caused by a massive build up of hydrogen peroxide due to wear and tear of our hair follicles.
The hydrogen peroxide ends up blocking the normal production of melanin, an team of European scientists recently reported in the FASEB scientific journal, published by the Federation of the American Societies for Experimental Biology. [rc]
© BBC MMIX
June 12, 2009
JAPAN: Experts close to roots of greying
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LONDON, England / BBC News / Health / June 12, 2009
The grey hairs that develop with age really are signs of stress, at least of the cellular kind, say scientists.
Genotoxic stress, namely anything that damages the genetic code of life DNA, causes a malfunction of the cells ultimately responsible for hair colour.
Going grey can be distinguished.
The stress sets off a chain of reactions involving specialised cells called melanocyte stem cells, their work on mice in Cell journal reveals.
Similar mechanisms appear to be at work in humans too, they say.
The findings could help explain why people with Ataxia telangiectasia, a rare, neurodegenerative syndrome caused by a mutation in a gene called ATM, go grey prematurely.
In their study, Dr Emi Nishimura and colleagues found the ATM "caretaker" gene serves as a checks and measures system to stop melanocyte stem cells going awry.
It is the job of these cells within the hair follicles to make the mature pigment-producing melanocytes that give hair its youthful colour.
Damaged DNA
Researchers have already traced greying to the gradual dying off of the stem cells.
But this is not the only way the stem cells are depleted.
They also progressively make errors, turning or differentiating into fully committed pigment cells in the wrong place within the hair follicle, where they are useless for colouring hair.
And the latest work on mice shows irreparable DNA damage, as caused by ultraviolet light and ionising radiation, is responsible.
Dr Nishimura of Kanazawa University said: "Once stem cells are damaged irreversibly, the damaged stem cells need to be eliminated to maintain the quality of the stem cell pool.
"We found that excessive genotoxic stress triggers differentiation of melanocyte stem cells."
But others believe going grey is caused by a massive build up of hydrogen peroxide due to wear and tear of our hair follicles.
The hydrogen peroxide ends up blocking the normal production of melanin, an team of European scientists recently reported in the FASEB scientific journal, published by the Federation of the American Societies for Experimental Biology. [rc]
© BBC MMIX
Genotoxic stress, namely anything that damages the genetic code of life DNA, causes a malfunction of the cells ultimately responsible for hair colour.
Going grey can be distinguished.
The stress sets off a chain of reactions involving specialised cells called melanocyte stem cells, their work on mice in Cell journal reveals.
Similar mechanisms appear to be at work in humans too, they say.
The findings could help explain why people with Ataxia telangiectasia, a rare, neurodegenerative syndrome caused by a mutation in a gene called ATM, go grey prematurely.
In their study, Dr Emi Nishimura and colleagues found the ATM "caretaker" gene serves as a checks and measures system to stop melanocyte stem cells going awry.
It is the job of these cells within the hair follicles to make the mature pigment-producing melanocytes that give hair its youthful colour.
Damaged DNA
Researchers have already traced greying to the gradual dying off of the stem cells.
But this is not the only way the stem cells are depleted.
They also progressively make errors, turning or differentiating into fully committed pigment cells in the wrong place within the hair follicle, where they are useless for colouring hair.
And the latest work on mice shows irreparable DNA damage, as caused by ultraviolet light and ionising radiation, is responsible.
Dr Nishimura of Kanazawa University said: "Once stem cells are damaged irreversibly, the damaged stem cells need to be eliminated to maintain the quality of the stem cell pool.
"We found that excessive genotoxic stress triggers differentiation of melanocyte stem cells."
But others believe going grey is caused by a massive build up of hydrogen peroxide due to wear and tear of our hair follicles.
The hydrogen peroxide ends up blocking the normal production of melanin, an team of European scientists recently reported in the FASEB scientific journal, published by the Federation of the American Societies for Experimental Biology. [rc]
© BBC MMIX
