Skin and new hair
Stem cells isolated from the skin have the power to self-renew when cultured in the laboratory.
In a major breakthrough, researchers from the Howard Hughes Medical Institute have demonstrated that stem cells isolated from the skin of mice have the power to self-renew when cultured in the laboratory, as well as to differentiate into skin and functioning hair follicles when grafted onto mice.
The researchers led by Elaine Fuchs and colleagues at The Rockefeller University isolated stem cells from a structure called the bulge, located within each hair follicle by fusing antibodies to characteristic cell surface molecules.
The scientists' analyses of the biochemical characteristics of the isolated mouse stem cells revealed that the bulge contained two distinct populations of stem cells. While the "basal" cells, are active during early development but` the "suprabasal" cells appear only after the first hair generation cycle.
Both types of cells, even after being cultured, produced hair follicles when grafted onto the skin of a strain of hairless mice.
"Previously, researchers have done similar transplant experiments with dissected parts of the hair follicle. And, while they've had evidence that hair follicle structures were forming, they didn't see generation of hair. In contrast, in our experiments, we saw quite a density of hairs, in some cases at a density that's very similar to that of normal mouse fur," Fuchs said.
She added that the stem cells they isolated showed a molecular signature of gene activity that demonstrates their "stemness" that represents the beginning of a broader effort to compare the genes activated in many stem cell types, to understand the factors that control their proliferation and differentiation.
"The information that we have now on the 'stemness' genes is allowing us to narrow in on some of the similarities among stem cells of the body," she added.