A team led by Keck Medicine of the University of Southern California (USC) researchers found a possible pathway toward curing male pattern baldness and understanding regenerative properties in organs by plucking 200 hairs in a specific pattern and density, inducing up to 1,200 replacement hairs to grow in a mouse.
The study, published in the April 9 edition of the peer-reviewed journal Cell, showed that hair follicles plucked in certain configurations signal distress by releasing inflammatory proteins, which recruit immune cells to rush to the site of the injury. These immune cells then secrete signaling molecules such as tumor necrosis factor alpha (TNF-α), which, at a certain concentration, communicate to both plucked and un-plucked follicles that it’s time to grow hair.
“The work leads to potential new targets for treating alopecia, a form of hair loss,” said Cheng-Ming Chuong, PhD, corresponding author on the research and professor of pathology at the Keck School of Medicine of USC. “It is a good example of how basic research can lead to a work with potential translational value.”
The research was led by first author and visiting scholar Chih-Chiang Chen, PhD, assistant professor of pathology at Yang Ming University, Taiwan. As a dermatologist, Chen knew that hair follicle injury affects its adjacent environment. The Chuong lab had already established that this environment can influence hair regeneration. Based on this combined knowledge, they reasoned that they might be able to use the environment to activate more follicles.
To test the concept, Chen devised a strategy to pluck 200 hair follicles, one by one, in different configurations on the back of a mouse. When plucking the hairs in a low-density pattern from an area exceeding 6 millimeters in diameter, no hairs regenerated. However, higher-density plucking from circular areas with diameters between 3 and 5 millimeters triggered the regeneration of between 450 and 1,300 hairs, including ones outside of the plucked region.
Working with Arthur D. Lander, MD, PhD, professor of developmental and cell biology at the University of California, Irvine, the team showed that this regenerative process relies on the principle of “quorum sensing,” which defines how a system responds to stimuli that affect some, but not all, members. In this case, quorum sensing underlies how the hair follicle system responds to the plucking of some, but not all, hairs.
“The implication of the work is that parallel processes may also exist in the physiological or pathogenic processes of other organs, although they are not as easily observed as hair regeneration,” said Chuong.
In addition to these latest findings, the journal Science recently selected Chuong’s work on how the regulation of feather follicle stem cells contributed to the evolution of feathered dinosaurs into modern birds as one of the Top 10 breakthroughs of 2014. Chuong was also inducted as a fellow of the American Association for the Advancement of Science (AAAS) in February 2015.
Additional coauthors on the Cell paper are Ting Xin Jiang and Randall B. Widelitz from USC; Lei Wang from The Fourth Military Medical University, China; Maksim V. Plikus, Raul Ramos, Christian F. Guerrero-Juarez from University of California, Irvine; Philip J. Murray from University of Dundee, Scotland; Michael W. Hughes from National Cheng Kong University, Taiwan; Oscar K. Lee from National Yang-Ming University and Veterans General Hospital, Taiwan; and Songtao Shi from the University of Pennsylvania.
Research funding came from the National Institute of Arthritis and Musculoskeletal and Skin Diseases (RO1-AR42177, R01-AR067273, AR47364 and AR60306); NSC (100-2314-B-075-044 and 101-2314-B-075-008-MY3); the Taipei Veterans General Hospital (VN103-12, V103C-010, V102B-009 and R-1100403); the National Institutes for Health (R01DE17449); an Edward Mallinckrodt Jr. Foundation grant; a California Institute for Regenerative Medicine (CIRM) training grant (TG2-01152); the National Science Foundation Graduate Research Fellowship Program (DGE-1321846); and the Top Notch University plan of Cheng Kong University, Taiwan.