Epidermal cells sculpt sensory nerve endings through actomyosin contractility

Peripheral sensory neurons extend into the skin to discern various stimuli, including mechanical, thermal, and noxious sensations. In the epidermis, nerve fibers end nearby tight junctions to prevent contact with the external environment. While epidermal maturation orchestrates tight junction formation, its influence on nerve terminal organization remains unclear.

A recent study reveals that activating Notch, an essential driver of epidermal maturation, leads to almost total removal of epidermal nerve connections. This effect primarily stems from enhanced contractility within the epidermis, rather than disrupted differentiation. Inducing epidermal contractility caused nerve fibers to be removed in a specific spatial pattern, while returning contractility to normal restored this loss.

Actomyosin contractility is most intense in the granular regions of the epidermis, where tight junctions exist and nerve fibers terminate. Blocking nonmuscle myosin II permitted nerve fibers to grow beyond their usual termination site, resulting in heightened sensitivity to touch. In summary, these results illustrate that epidermal contractility shapes sensory nerve endings by precisely trimming their locations, thereby defining a mechanical barrier that limits the growth of neurons.