Human hair follicle and scalp skin organ culture: highly clinically relevant models for testing hair care products

Hair Follicle Chemosensation: TRPM5 Signaling Is Required for Anagen Maintenance.

In News, Press Releases by Anja Borrosch

Being able to sense and process environmental cues is among the most fundamental requirements of life and thus not only restricted to the specialized cells that we use to smell and taste. In fact, a team of scientists from Monasterium Laboratory, the University of Miami (USA) and the University of Manchester (UK) has recently discovered that our hair follicles, the mini-organs that produce hair, can “smell” via olfactory receptors and thereby regulate their own growth (Cheret et al. Nat Commun 2018). Following up this innovative line of research, Monasterium Laboratory has led the search for additional chemosensory receptors with similar functions and has just reported their latest discovery in this ongoing quest to elucidate the chemosensation biology of hair growth: our scalp hair follicles can even “smell” pheromones contained in some perfumes and then get growth-stimulated by these (Mardaryev et al. J Invest Dermatol 2021).

This discovery is quite exciting for several reasons.

First, it has long been disputed whether pheromones have any function at all in human life, as opposed to insects and other mammals. This new work suggests that they sure do, but possibly not only (or not even…?) in their popularly known main function of attracting partners of the other sex.

Second, the Monasterium Laboratory team could identify both, two well-defined cosmetic agents that exert hair growth-stimulating effect (but which had never been suspected to promote human hair growth!) and the underlying chemosensory receptor responsible for mediating this pheromone effect. This receptor, called TRPM5, is a member of the family of Transient Receptor Potential (TRP) ion channels that sense and integrate many diverse physical and chemical stimuli and translate these into changes in cell function, such as stimulation of human hair growth in the current case. This was quite unexpected as the stimulation of other TRP channels the team had investigated before worked as a molecular brake on hair growth.

Third, and this is where things get even more fascinating, when the scientists experimentally counteracted the signalling through this chemoreceptor the growth of organ-cultured scalp hair follicles was inhibited. This begs the intriguing question: what are hair follicles smelling on a daily basis in human skin and in real life via their TRMP5 channels – surely not pheromones? The Monasterium team does not have a definitive answer yet, but knowing that this channel is also stimulated by several other agents besides pheromones, this speculates that certain metabolites produced in the hair follicle itself, possibly including some that are released from the unusually rich populations of different bacteria and fungi that happily live in our hair follicles without causing any trouble in healthy skin, might be among the natural ligands that stimulate this putative “pheromone receptor”.

Together with their previous research on olfactory receptors, this new pioneering research of Monasterium Laboratory opens the door to a fascinating future world of “chemosensation cosmetics”: using cleverly chosen cosmetic ingredients, which tickle the right, ancient chemosensory receptors that appeared during evolution millions of years before any hairy mammals roamed the earth, is a promising, novel, and well-tolerated strategy to manage both, distressing hair loss and unwanted hair growth – without having to administer drugs.

Reference:

Mardaryev A, van Lessen M, Alam M, Jimenez Acosta F, Bíró T, Paus R.
J Invest Dermatol. 2021 Mar 24:S0022-202X(21)01012-5. doi: 10.1016/j.jid.2021.02.747

(Interested companies that would like to discuss cooperation and licensing opportunities at this hair follicle chemosensation research frontier are invited to contact Monasterium Laboratory’s Head of Innovation, Prof. Tamas Biro: t.biro@monasteriumlab.com.)

Über den Autor

Anja Borrosch