Our hair is pretty amazing—it protects and warms us, senses touch, and provides us with countless ways to show our style (or lack of).  Next time you look at your hair in the mirror, consider thanking it for the nifty ability of hair follicle stem cells to help injured skin heal.

Hair follicles are the tiny organs that grow our hair.  They are regenerated throughout our lives thanks to several populations of stem cells that reside in the hair follicle.  These hair follicle stem cells are also able to migrate to wounded skin in order to help regenerate and heal the area.   This ability is quite handy—when the skin in a hairy area is injured, it heals faster and more efficiently than a wound on hairless skin.  Recently, a research group illuminated the importance of a protein called Lhx2 in the repair of injured skin by hair follicle stem cells.  Lhx2 is a transcription factor, meaning it binds to DNA and affects how genes are turned on or off, and is known to function in organ development and stem cell activity.  In their recent report, Mardaryev and colleagues found Lhx2 in hair follicle stem cells.  When nearby skin is injured, Lhx2 ensures that hair follicle stem cells function in skin regeneration, while at the same time inhibiting the pathway that would normally allow the stem cells to grow hair instead.  Images above show a hair follicle following an injury to the skin.  Lhx2 (magenta) levels increase in the hair follicle by the third and fifth day after injury (middle and right images).  In addition, most of the dividing cells (green) are also Lhx2-containing cells, highlighting the importance of Lhx2 in the proliferation of cells required for the skin to heal. 

For a more scientifically detailed description of this image, check out my post on The Node, the community forum for and by developmental biologists.