Piezo2 expression in corneal afferent neurons.

Area of Science:

• Neuroscience
• Sensory Biology
• Molecular Physiology

Background:

• Piezo channels are a novel class of mechanically sensitive ion channels.
• Corneal afferent neurons have well-defined sensory modalities.
• Understanding Piezo channel function in the cornea is crucial for pain research.

Purpose of the Study:

• To investigate Piezo channel expression in guinea pig corneal sensory neurons.
• To determine if Piezo2 is expressed in specific neuronal subtypes within the cornea.
• To test the hypothesis that Piezo2-expressing neurons are distinct from polymodal nociceptors and cold-sensing neurons.

Main Methods:

• Retrograde tracing to identify corneal afferent neurons.
• Double-label in situ hybridization and immunohistochemistry to assess molecular profiles.
• Analysis of Piezo2, CGRP, NF200, and TRPM8 expression in trigeminal ganglion and corneal neurons.

Main Results:

• Piezo2 was detected in approximately 26% of trigeminal ganglion neurons and 30% of corneal afferent neurons.
• Piezo2-expressing corneal afferent neurons were predominantly medium- to large-sized, NF200-IR, and non-CGRP-IR.
• No co-expression of Piezo2 and TRPM8 was observed, indicating Piezo2 is not in cold-sensing neurons.

Conclusions:

• Piezo2 is expressed in a distinct subpopulation of corneal afferent neurons.
• These neurons are unlikely to be polymodal nociceptors or cold-sensing neurons.
• Piezo2 is a strong candidate for transducing noxious mechanical stimuli in the cornea.