Lighting Up Mechanosensation: dyeing to see PIEZO2

Abstract

Sensory neurons gather information about mechanical forces from both the environment and internal organs to regulate physiology. PIEZO2 is a mechanosensory ion channel critical for touch, proprioception and bladder stretch sensation, yet its broad expression in sensory neurons and elsewhere suggests it may have undiscovered physiological roles. To fully understand mechanosensory physiology, we must know where and when PIEZO2-expressing neurons detect force. The fluorescent styryl dye FM 1-43 was shown to permeate several ion channels in cell culture and label sensory neurons. Surprisingly, we find that the vast majority of FM 1-43 somatosensory neuron labeling in vivo is dependent on PIEZO2-activity within nerve endings. We illustrate the potential of FM 1-43 by using it to identify novel Piezo2-expressing urethral neurons that are engaged by urination. These data reveal that FM 1-43 is a functional probe for mechanosensitivity via PIEZO2 activation in vivo and will facilitate the characterization of known and novel mechanosensory processes.