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.
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
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 Wnt pathway 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 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.
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 human skin scars but does not regenerate hair follicles.
In adult mice, 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.
The study was funded by the National Institutes of Health (R01AR46837, P30AR057217, RO1AR055309, R01HL105732, T32AR007465), the Edwin and Fannie Gray Hall Center for Human Appearance at Penn Medicine, and The Dermatology Foundation.
Additional collaborators on the research include co-lead authors Denise Gay and Ohsang Kwon, Zhikun Zhang, Michelle Spata, Maksim V Plikus, Phillip D. Holler, Zaixin Yang, Elsa Treffeisen, Arben Nace, X Zhang, Sheena Baratono and Sarah E. Millar from Penn's Department of Dermatology, along with collaborators from New York University Langone Medical Center (Mayumi Ito), Seoul National University College of Medicine, Chungnam National University in Daejeon, Korea, Texas A&M University Health Science Center, and Washington University School of Medicine.
Cotsarelis, Ito and Kwon are listed as inventors on patent applications related to hair-follicle neogenesis, Wnt and FGF9, which are owned by the University of Pennsylvania. Cotsarelis also serves on the scientific advisory board and has equity in Follica, a start-up company that has licensed related patents from the University of Pennsylvania starting in 2007. Cotsarelis was also a co-founder of Follica.
Penn Medicine is one of the world's leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System, which together form a $4.3 billion enterprise.
The Perelman School of Medicine has been ranked among the top five medical schools in the United States for the past 16 years, according to U.S. News & World Report's survey of research-oriented medical schools. The School is consistently among the nation's top recipients of funding from the National Institutes of Health, with $398 million awarded in the 2012 fiscal year.
The University of Pennsylvania Health System's patient care facilities include: The Hospital of the University of Pennsylvania -- recognized as one of the nation's top "Honor Roll" hospitals by U.S. News & World Report; Penn Presbyterian Medical Center; and Pennsylvania Hospital — the nation's first hospital, founded in 1751. Penn Medicine also includes additional patient care facilities and services throughout the Philadelphia region.
Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2012, Penn Medicine provided $827 million to benefit our community.
Kim Menard | EurekAlert!
Biofilm discovery suggests new way to prevent dangerous infections
23.05.2017 | University of Texas at Austin
Another reason to exercise: Burning bone fat -- a key to better bone health
19.05.2017 | University of North Carolina Health Care
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy