Shuttling genes into hair follicles can alter hair colour, scientists have shown for the first time. The experiments on mice also suggest genetic modification treatments for hair loss will be possible in future.

Closer to reality is the prospect of restoring colour to greying hair. But it will be some years before the pioneering work that has given mice shocks of gaudy green hair reaches the salon.

“They’re punk mice, you could say,” jokes Robert Hoffman, head of the team which developed the mice with green hair at AntiCancer, a Californian biotech company based in San Diego.

But he warns that the breakthrough is very much a first step, and that genes to treat baldness cannot be delivered in the same way until someone identifies them. Candidates include the genes that suppress the overproduction of the “superandrogen”, dihydrotestosterone. This hormone is also implicated in acne, which in theory could also be helped by the new approach.


Skin slivers

The genes transferred into the mice’s hair follicles make a fluorescent protein from jellyfish, which glows green in blue light. To load the jellyfish genes, Hoffman grew small sheets of mouse skin. After softening up the tissue with an enzyme called collagenase, he dunked the skin slivers in a solution containing an adenovirus similar to the one that causes colds.

The viruses had already been loaded with copies of the jellyfish gene. Hoffman had also removed the genes that that enable the virus to replicate, so that it would load its genetic cargo into mouse cells without replicating itself.

Within hours, Hoffman peered down the microscope and could see blobs of the green protein appearing in hair follicles, the sources of each new shaft of hair. In the treated skin slivers, 80 per cent of the growing hairs were now green.

And when he grafted the slivers onto mice lacking hair of their own, the transplanted hair continued developing normally in every way, except that it was green under blue light.

Pigment production

GM treatments to restore hair colour would need to increase the amount of the pigment melanin. Changing hair colour would mean switching the form of melanin produced. Black hair results from eumelanin, while red and brown hair owe their hue to a lighter form, called pheomelanin.

But no-one yet knows the molecular secret of blonde hair. “It’s one thing to restore pigment formation to a greying follicle, but quite another to modify the pigment,” says Hoffman. “So it’s not yet a replacement for the peroxide blonde.”

Once hair colour genes are discovered, it might be possible for people treated with them to switch them on and off whenever they want with hair creams that activate or turn off the genes.

Next, Hoffman plans experiments in albino mice. These lack the gene for tyrosinase, an enzyme that regulates the production of melanin, to see if pigment production can be restored by loading the missing gene.

Journal reference: Proceedings of the National Academy of Sciences (DOI: /10.1073/pnas.192453799)