Imperial College London researchers find hair follicles have an unique system to sense touch, launching neurotransmitters in response. This might shed light on inflammatory skin problem like eczema.
Scientists from Imperial College London have uncovered a covert mechanism within hair follicles that allow us to feel touch.
Before this discovery, it was commonly thought that touch was sensed solely through nerve endings in the skin and around hair follicles. This current research study exposes that cells inside the hair follicles– the entities enveloping the hair strand– can also sense touch in cell cultures.
The researchers also found that these hair roots cells launch the neurotransmitters histamine and serotonin in response to touch– findings that might assist us in the future to understand histamines function in inflammatory skin illness like eczema.
The Unexpected Role of Hair Follicles
Lead author of the paper Dr Claire Higgins, from Imperials Department of Bioengineering, said: “This is a surprising finding as we dont yet understand why hair follicle cells have this role in processing light touch. Since the hair follicle includes lots of sensory nerve endings, we now desire to determine if the hair roots is triggering particular kinds of sensory nerves for a unknown but distinct mechanism.”
A Touchy Subject
We feel touch utilizing a number of mechanisms: sensory nerve endings in the skin detect touch and send signals to the brain; highly innervated hair roots find the motion of hair fibers; and sensory nerves known as C-LTMRs, that are only found in hairy skin, procedure emotional, or feel-good touch.
Now, researchers might have uncovered a brand-new procedure in hair follicles. To perform the study, the researchers evaluated single-cell RNA sequencing information of human skin and hair roots and discovered that hair roots cells included a greater portion of touch-sensitive receptors than equivalent cells in the skin..
They developed co-cultures of human hair follicle cells and sensory nerves, then mechanically promoted the hair follicle cells, discovering that this caused activation of the surrounding sensory nerves.
Neurotransmitters in Touch Perception.
They then decided to examine how the hair follicle cells indicated to the sensory nerves. They adapted a technique understood as quick scan cyclic voltammetry to evaluate cells in culture and found that the hair follicle cells were launching the neurotransmitters serotonin and histamine in reaction to touch.
When they blocked the receptor for these neurotransmitters on the sensory neurons, the neurons no longer responded to the hair roots cell stimulation. When they blocked synaptic vesicle production by hair follicle cells, they were no longer able to indicate to the sensory nerves.
They for that reason concluded that in reaction to touch, hair roots cells release that trigger close-by sensory nerve cells.
The researchers also performed the very same explores cells from the skin rather of the hair roots. The cells reacted to light touch by releasing histamine, but they didnt release serotonin.
Dr Higgins said: “This is interesting as histamine in the skin contributes to inflammatory skin conditions such as eczema, and it has constantly been presumed that immune cells launch all the histamine. Our work uncovers a brand-new role for skin cells in the release of histamine, with prospective applications for eczema research.”.
Looking Forward.
The researchers note that the research study was carried out in cell cultures, and will require to be reproduced in living organisms to validate the findings. If the hair follicle is activating particular types of sensory nerves, the scientists also desire to figure out. Considering that C-LTMRs are only present within hairy skin, they are interested to see if the hair roots has a special mechanism to indicate to these nerves that we have yet to uncover.
Reference: “Mechanical stimulation of human hair roots external root sheath cultures triggers surrounding sensory nerve cells” by Julià Agramunt, Brenna Parke, Sergio Mena, Victor Ubels, Francisco Jimenez, Greg Williams, Anna DY Rhodes, Summik Limbu, Melissa Hexter, Leigh Knight, Parastoo Hashemi, Andriy S. Kozlov and Claire A. Higgins, 27 October 2023, Science Advances.DOI: 10.1126/ sciadv.adh3273.
This work was funded by Engineering and Physical Research Council (EPSRC, part of UKRI), Proctor & & Gamble, Wellcome Trust, and Biotechnology and Biological Sciences Research Council (BBSRC, part of UKRI).