Scientists identify sensor underlying mechanical itch

Good news! This could be a breakthrough!

"Scientists at Scripps Research have identified a protein in sensory nerves that works as a key detector of itch—specifically the “mechanical” itch stimulus of crawling insects, wool fibers, or other irritating objects that touch the skin.

The discovery, published June 22, 2022, in Nature, is the first identification of a sensor for mechanical itch rather than chemically-triggered itch. It could lead to better treatments for itch conditions such as eczema and psoriasis. ...
PIEZO1’s role in mechanical itch was unexpected. Patapoutian won a share of last year’s Nobel Prize for Medicine or Physiology for his lab’s pioneering research on PIEZO1 and its sister-protein PIEZO2. These unique, propeller-shaped “mechanosensor” ion channels are embedded in the outer membranes of many cell types. They become activated when mechanically distorted, opening their ion channels and triggering various downstream events. Since 2010, Patapoutian and colleagues have shown that PIEZO2 is a key mechanosensor for light touch, the feeling of the positioning of the body and limbs, and the urge to urinate—all via nerves in various tissues and organs. By contrast, the researchers have found that PIEZO1 has a variety of non-sensory roles throughout the body, for example in blood vessels and red blood cells. ...
By contrast, mice lacking PIEZO1 in their sensory neurons scratched themselves far less when stimulated on the skin with filaments that normally would trigger strong itch sensations. The researchers also showed that a PIEZO1-blocking compound alleviates scratching behaviors in mice with the equivalent of eczema. ..."

From the abstract:

"Itch triggers scratching, a behavioural defence mechanism that aids in the removal of harmful irritants and parasites. ... Mechanical itch can be triggered by light sensations such as wool fibres or a crawling insect. In contrast to chemical itch pathways, which have been extensively studied, the mechanisms that underlie the transduction of mechanical itch are largely unknown. Here we show that the mechanically activated ion channel PIEZO1 is selectively expressed by itch-specific sensory neurons and is required for their mechanically activated currents. Loss of PIEZO1 function in peripheral neurons greatly reduces mechanically evoked scratching behaviours and both acute and chronic itch-evoked sensitization. Finally, mice expressing a gain-of-function Piezo1 allele exhibit enhanced mechanical itch behaviours. Our studies reveal the polymodal nature of itch sensory neurons and identify a role for PIEZO1 in the sensation of itch."

Scripps Research scientists identify sensor underlying mechanical itch | Scripps Research Finding could lead to better drug treatments for chronic itch conditions, like eczema [or psoriasis]

PIEZO1 transduces mechanical itch in mice (open access)

Fig. 1: PIEZO1 is expressed in mouse and human putative itch receptors.