Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New research clarifies how stem cells get activated to produce new hair

03.03.2016

Adult stem cells provide the body with a reservoir from which damaged or used up tissues can be replenished. In organs like the intestines and skin, which need constant rejuvenating, these stem cells are dividing frequently. But in other body structures, including the hair follicles, they are held in a quiescent state--one in which they don't reproduce until they receive signals from their surroundings that it's time to regenerate.

It makes intuitive sense that stem cells, being such a valuable resource, would be used sparingly. Yet scientists have limited understanding of how their quiescence is regulated, and are even unsure of its precise biological function. In a study published recently in PNAS, Elaine Fuchs, Rebecca C. Lancefield Professor and head of the Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, and Kenneth Lay, a graduate student in her lab, report on new insights into the biological signals that make hair follicle stem cells oscillate between states of quiescence and regenerative activity.


Hair follicle stem cells lacking the protein FOXC1 can only retain one old bulge in their hair follicles, while normal stem cells can keep up to four.

Credit: The Laboratory of Mammalian Cell Biology and Development at Rockefeller University/PNAS

"In an earlier study, my lab showed that when mice age, the old fat in their skin produces higher levels of a secreted signal, called BMP," Fuchs says. "This signal acts as a molecular brake on the hair follicle stem cells, causing them to spend much longer times in quiescence."

In the present study, Lay identified a stem cell gene that is activated by BMP signaling, and showed that when this gene is missing, the stem cells grow hairs with dramatically shorter intervals. "We thought initially that the key to hair growth might be the fountain of youth," Fuchs says, "but the mice's hair coat surprisingly thinned and greyed precociously."

More growth and fewer bulges

Usually the stem cells then create a new bulge along with the new hair, while ensuring that the old bulge and the old hair stay put in the hair follicle. Only the new bulge can make another new hair, but the old bulge is kept in place to maintain a thick and lush coat. In mice, hair follicles can accumulate up to four of these bulges.

When Lay and Fuchs created mice that lack FOXC1--by disabling or "knocking out" the gene that produces this protein--they observed that the animals' hair follicle stem cells spent more time growing hairs and less time in quiescence. Over the course of nine months, while hair follicles from normal mice grew four new hairs, those from the FOXC1 knockout mice had already made new hairs seven times. "The knockout stem cells enter an overactive state in which they can't establish quiescence adequately," explains Lay.

The researchers also found that in the absence of FOXC1, hair follicles always had only one hair despite having made new hairs seven times. This is because these hair follicles could not retain their old bulges, though they generated a new bulge without a problem. As the stem cells started proliferating more, they became less able to stick together. As a result, their old bulges did not stay properly tethered to the hair follicle when the newly growing hair pushed past it. And since the bulge emits quiescence signals, its loss activated the remaining stem cells even faster.

Going grey and going bald

While the hair follicle stem cells of FOXC1-deficient mice produce hairs at a relatively breakneck pace, this profligate growth seems to wear them out. Older knockout mice had sparser, greyer coats, and they could not regenerate their fur as quickly as their normal age-matched or younger peers. A similar phenomenon has been described in mouse hematopoietic stem cells, which give rise to blood cells--those stem cells that are more active in young animals appear to become exhausted as the animals grow older.

"Hair follicle stem cells influence the behavior of melanocyte stem cells, which co-inhabit the bulge niche," explains Fuchs. "Thus, when the numbers of hair follicle stem cells declined with age, so too did the numbers of melanocyte stem cells, resulting in premature greying of whatever hairs were left." Not much is known about naturally occurring hair loss with age, but these balding knockout mice may provide a model to study it.

Media Contact

Katherine Fenz
kfenz@rockefeller.edu
212-327-7913

 @rockefelleruniv

http://www.rockefeller.edu 

Katherine Fenz | EurekAlert!

More articles from Life Sciences:

nachricht Zap! Graphene is bad news for bacteria
23.05.2017 | Rice University

nachricht Discovery of an alga's 'dictionary of genes' could lead to advances in biofuels, medicine
23.05.2017 | University of California - Los Angeles

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Turmoil in sluggish electrons’ existence

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...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

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...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Scientists propose synestia, a new type of planetary object

23.05.2017 | Physics and Astronomy

Zap! Graphene is bad news for bacteria

23.05.2017 | Life Sciences

Medical gamma-ray camera is now palm-sized

23.05.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>