Growth factor responsible for triggering hair follicle generation during wound healing identified

June 2, 2013
Researchers in the Perelman School of Medicine at the University of Pennsylvania have determined the role of a key growth factor, found in skin cells of limited quantities in humans, that helps hair follicles form and regenerate during the wound healing process. This growth factor, Fgf9, is initially secreted from gamma delta T cells, an unconventional, rare subset of T cells involved in the immune response. Once released, Fgf9 serves as the catalyst for a signal sent via the dermal Wnt pathway. The signal prompts further expression of Fgf9 in structural cells called fibroblasts, and adds to the generation of new hair follicles. Researchers believe that this growth factor could be used therapeutically for people with various hair and scalp disorders. The study appears in an advance online publication of Nature Medicine. Credit: George Cotsarelis and Elsa Treffeisen/Penn Medicine

Researchers in the Perelman School of Medicine at the University of Pennsylvania have determined the role of a key growth factor, found in skin cells of limited quantities in humans, which helps hair follicles form and regenerate during the wound healing process. When this growth factor, called Fgf9, was overexpressed in a mouse model, there was a two- to three-fold increase in the number of new hair follicles produced. Researchers believe that this growth factor could be used therapeutically for people with various hair and scalp disorders. The study appears in an advance online publication of Nature Medicine.

"The findings help explain why humans don't regenerate their hair after wounding," said senior author George Cotsarelis, MD, professor and chair of Dermatology. "The study also points us to a way to treat wounds and grow hair."

Following up on earlier work, which showed that increased signaling from the doubled the number of new hair follicles, the Penn team looked further upstream in the pathway and identified an important cascade of signals that prompt further expression, as well as perpetuate and amplify signals sent during a crucial phase of hair-follicle regeneration.

Fgf9 is initially secreted from gamma delta , an unconventional, rare subset of T cells involved in the immune response. Once released, Fgf9 serves as the catalyst for a signal sent via the dermal Wnt pathway. The signal prompts further expression of Fgf9 in structural cells called fibroblasts, and adds to the generation of new hair follicles.

When a wound occurs in an adult person, hair follicle growth is blocked and the skin heals with a scar. However, hair does regenerate to a great extent in the wound-healing process in mice. The team compared how the process works in adult mice versus humans. Humans have low numbers of gamma delta T cells in their skin compared to mice, and this may explain why scars but does not regenerate hair follicles.

In , the amount of Fgf9 secreted modulates hair-follicle regeneration after wounding. When Fgf9 was reduced, there was a decrease in wound-induced hair follicle growth. Conversely, when Fgf9 was increased, there was a two- to three-fold increase in the number of new hair follicles, equal to the amount seen in the mice expressing Wnt. Importantly, when the investigators added Fgf9 back to the wounds that do not normally regenerate, FGF9 triggered the molecular cascade of events necessary for skin and hair regeneration; thus, leaving the door open for using Fgf9 to treat wounds and hair loss in people.

The Penn team suggests that, given the differences in skin development and regeneration in response to wounding, treatments intended to compensate for the lack of Fgf9 may be most effective if timed with a wounding response. "Testing activators of Fgf9 or Wnt pathways during the wound healing process may be warranted," they stated.

Explore further: New research provides clues on why hair turns gray

More information: Fgf9 from dermal gd T cells induces hair follicle neogenesis after wounding, Nature Medicine, DOI: 10.1038/nm.3181

Related Stories

New research provides clues on why hair turns gray

June 14, 2011
A new study by researchers at NYU Langone Medical Center has shown that, for the first time, Wnt signaling, already known to control many biological processes, between hair follicles and melanocyte stem cells can dictate ...

Bioluminescence imaging lights up stem cell therapy for hair growth

June 11, 2012
Finding a way to restore hair growth after substantial hair loss is something of an obsession worldwide. Investigators at the Society of Nuclear Medicine's 2012 Annual Meeting presented how stem cell research for the development ...

A Viagra follow-up? Drug used to treat glaucoma actually grows human hair

October 26, 2012
If you're balding and want your hair to grow back, then here is some good news. A new research report appearing online in The FASEB Journal shows how the FDA-approved glaucoma drug, bimatoprost, causes human hair to regrow. ...

Recommended for you

Make way for hemoglobin

August 18, 2017
Every cell in the body, whether skin or muscle or brain, starts out as a generic cell that acquires its unique characteristics after undergoing a process of specialization. Nowhere is this process more dramatic than it is ...

Bio-inspired materials give boost to regenerative medicine

August 18, 2017
What if one day, we could teach our bodies to self-heal like a lizard's tail, and make severe injury or disease no more threatening than a paper cut?

Are stem cells the link between bacteria and cancer?

August 17, 2017
Gastric carcinoma is one of the most common causes of cancer-related deaths, primarily because most patients present at an advanced stage of the disease. The main cause of this cancer is the bacterium Helicobacter pylori, ...

Two-step process leads to cell immortalization and cancer

August 17, 2017
A mutation that helps make cells immortal is critical to the development of a tumor, but new research at the University of California, Berkeley suggests that becoming immortal is a more complicated process than originally ...

Female mouse embryos actively remove male reproductive systems

August 17, 2017
A protein called COUP-TFII determines whether a mouse embryo develops a male reproductive tract, according to researchers at the National Institutes of Health and their colleagues at Baylor College of Medicine, Houston. The ...

New Pathology Atlas maps genes in cancer to accelerate progress in personalized medicine

August 17, 2017
A new Pathology Atlas is launched today with an analysis of all human genes in all major cancers showing the consequence of their corresponding protein levels for overall patient survival. The difference in expression patterns ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.