The research, published in the December 15 issue of the journal Nature, was performed by a group of prominent stem-cell researchers from the Keck School of Medicine of the University of Southern California.
"What we found is that feather stem cells are distributed in a ring configuration around the inner wall of the vase-shaped feather follicle. This is different from hair stem cells, which are located in a bulge outside the follicle," explains Cheng-Ming Chuong, M.D., Ph.D., professor of pathology at the Keck School and principal investigator on this study.
Feather stem cells are of interest to scientists because of their profound regenerative abilities. A bird in nature molts twice a year. With more than 20,000 feathers on the average bird, Chuong notes, that means there are a lot of active, ongoing regenerative events in an adult bird.
Chuong and his USC colleagues identified epithelial stem cells within a chicken-feather follicle by giving the chickens water containing a non-radioactive label that was then incorporated and retained only in the putative epithelial stem cells. They showed that these cells were pluripotent-retaining the ability to differentiate into many different cell types-by taking the purported stem cells from quail-feather follicles and transplanting them into a chicken host. (Quail cells can be differentiated from chicken cells by cellular markers.) This demonstrated that only the labeled cells were pluripotent.
These stem cells, the researchers found, are well protected in the follicular base of each individual feather follicle. As they proliferate and differentiate, their progeny is displaced upward to create a feather. When the bird molts, the quill of the feath
Contact: Jon Weiner
University of Southern California