Although bald is attractive to many people, those who actually have lost all their hair may be secretly hoping for a scientific breakthrough... or miracle. Good news: New research has identified a molecular pathway that, when activated, prompts hair growth from dormant hair follicles and, when blocked, prevents the growth of unwanted hair. "While more research is needed to improve our understanding of this pathway… if delivered in a limited, safe and controlled way, agents that activate Wnt signaling might be used to promote hair growth in dormant hair follicles in conditions such as male pattern baldness," said Sarah Millar, professor of dermatology and of cell and developmental biology at the University of Pennsylvania, in a press release.
What exactly is Wnt signaling?
Signal transduction pathways, no matter how complicated, follow the same general sequence of events. First, signaling molecules (ligands) bind to receptor proteins on the surface of the cell, causing a transformation of the receptor protein. Next, a second messenger, one that is able to pass through the cell membrane, transfers information to the cell's interior. In turn, this elicits a physiological response after which the signal may be terminated.
At the cellular level, all developmental processes — whether they result in a newborn baby or a worm — are controlled by the cooperative actions of different signal transduction pathways. Throughout development processes, Wnt signaling is required to choreograph complex cell behaviors. For example, the transfer of cellular information along this particular transduction pathway controls cell proliferation, stem cell maintenance, cell fate decisions, organized cell movements, and the establishment of tissue polarity. When functioning improperly, Wnt signaling has been implicated in cancer and degenerative disease; at the same time, Wnt signaling is complex and often less predictable than originally believed and for these reasons it has become the subject of much research.
For a recent study conducted at the University of Pennsylvania, then, the team of researchers focused their examination on Wnt proteins, which activate signaling via a secondary messenger, the molecule beta-catenin. When the researchers disrupted Wnt signaling in an animal model with an inhibitor, they observed that hair growth was prevented though stem cells were maintained within the dormant hair follicles. When they removed the inhibitor, the Wnt/beta-catenin pathway resumed normal function, the stem cells were activated, and hair growth was restored. Surprisingly, the team also discovered that the Wnt/beta-catenin pathway was also active in non-hairy regions, such as on the palms of hands and the tongue, as well as between hair follicles on the surface of the skin.
“Our results suggest that therapeutics capable of decreasing levels of Wnt/beta-catenin signaling in the skin could potentially be used to block growth of unwanted hair, and/or to treat certain skin tumors,” Millar explained in a press release. In other words, scientists should soon be looking to manipulate the Wnt/beta-catenin signaling pathway when designing new drugs to treat skin cancer, unwanted hair growth, and even hair loss. Soon those who do not aspire to looking like a skinhead may soon have a new option in their cosmetic arsenal.
Source: Choi YS, Zhang Y, Xu M, et al. Distinct Functions for Wnt/Beta-Catenin in Hair Follicle Stem Cell Proliferation and Survival and Interfollicular Epidermal Homeostasis. Cell Stem Cell. 2013.