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Hair
tomorrow?
It’s likely
that many of the 30 million balding men in the United States—roughly
40 percent of those over age 35—would do just about anything
for a bad-hair day. Providing a strand of hope for these men, Chicago
researchers have discovered a way to stimulate the growthof hair
follicles. One day, their technique may safely reverse balding.
Ordinarily,
hair-follicle formation is a once-in-a-lifetime event, occurring
as the fetus develops in the womb. A lack of understanding of how
hair follicles form has been a major block to the development of
new and improved hair-loss therapies.
Now—led by Elaine Fuchs, the Amgen professor in the departments
of molecular genetics and cell biology—a research team from
the University’s Howard Hughes Medical Institute has made hair
follicles form in the mature skin cells of mice. The team’s
findings, reported in the November 25 issue of Cell, indicate that
the molecule beta-catenin, along with its associated partner proteins,
may be the long-sought messenger that instructs embryonic cells
to become hair follicles.
“This
is exciting because current treatments for baldness only work if
there are living follicles left, or if the patient undergoes hair
transplant surgery,” explains Fuchs. “Our research shows
that new follicles can be created from adult skin cells if certain
molecular players are induced to act.”
Most of the
embryonic cells have the capability to become a variety of cells.
They ultimately become a particular type of cell based on tiny differences
in the concentration of a few chemicals and molecules in their immediate
vicinity. While beta-catenin is used at all times to hold skin cells
together, before birth it can also accumulate at higher levels in
some skin cells and interact with another molecule called LEF-1.
When LEF-1 and beta-catenin join together in the same skin cell,
that cell becomes a hair follicle.
The team made
this discovery not in a quest for a cure for baldness, but while
conducting research into the general biology of how skin proteins
work. When they pursued the special function of beta-catenin, they
realized its potential clinical applications.
Postdoctoral fellow Uri Gat worked with graduate student Ramanuj
DasGupta and senior research specialist Linda Degenstein, AB’77,
to genetically engineer adult mice that produced an endless supply
of beta-catenin in their skin, causing their skin cells to revert
to embryonic cells capable of hair-follicle formation. “It
is amazing,” says Fuchs, “that this single genetic change
can cause an adult epidermal cell to become more like a fetal skin
cell, able to be either an epidermal or a hair-follicle cell.”
Fuchs cautions
that hair-follicle formation will require more study before hair
growth can be induced without unwanted side effects. Like many growth-promoting
factors, she explains, unchecked levels of beta-catenin can lead
to the development of tumors. In the engineered mice, benign tumors
grew in hair follicles as a result of excess beta-catenin—normal
mouse skin cells destroy beta-catenin that is not immediately used.
“This is a case of too much of a good thing leading to a bad
thing,” she says.
If researchers
can find a way to induce beta-catenin in skin cells just until new
follicles have formed and then turn it off, Fuchs suggests, tumor
formation may be prevented while hair follicles are still allowed
to develop—offering a potentially more effective option for
reversing baldness than topical hair-growth medications or hair
transplantation.—Sharon Parmet
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