|Staining of slow-cycling sweat gland cells |
(green) with the protein laminin (red) and
the fluorescent stain
DAPI (blue) (Image by Yvonne Leung)
Kobielak and his colleagues used a system to make all of the sweat gland cells in a mouse easy to spot: labeling them with green fluorescent protein (GFP), which is visible under ultraviolet light.
Over time, the GFP became dimmer as it was diluted among dividing sweat gland cells. After four weeks, the only cells that remained fluorescent were the ones that did not divide or divided very slowly -- a known property among stem cells of certain tissues, including the hair follicle and cornea. Therefore, these slow-dividing, fluorescent cells in the sweat gland's coiled lower region were likely also stem cells.
Then, Yvonne Leung, first author of the study, tested whether these fluorescent cells could do what stem cells do best, to differentiate into multiple cell types. To their surprise, these glowing cells generated not only sweat glands, but also hair follicles when placed in the skin of a mouse without GFP.
The researchers also determined that under certain conditions, the sweat gland stem cells could heal skin wounds and regenerate all layers of the epidermis.
"That was a big surprise for us that those very quiescent sweat gland stem cells maintain multilineage plasticity -- participating not only in their own regeneration, but also in the regeneration of hair follicles and skin after injury," said Kobielak, assistant professor of pathology at the Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research at USC.
The study offers exciting new possibilities for developing future stem cell-based treatments for skin and sweat gland-related conditions, slike hyperhidrosis or hypohidrosis (excessive or insufficient sweating). It could also lay the foundation for creating fully functional skin, containing both sweat glands and hair follicles for people who have suffered severe burnings.
1) Yvonne Leung, Eve Kandyba, Yi-Bu Chen, Seth Ruffins,Krzysztof Kobielak (2013). Label Retaining Cells (LRCs) with Myoepithelial Characteristic from the Proximal Acinar Region Define Stem Cells in the Sweat Gland Plos One DOI: 10.1371/journal.pone.0074174