Involvement of sensory neuron-TRPV4 in acute and chronic itch behaviors

Itch, particularly chronic itch, negatively impacts patients physical, social, and psychological well-being, leading to deterioration in their quality of life. Limited understanding of itch mechanisms hinders the development of effective antipruritic treatments.TRPV4, a multimodally activated nonselective cation channel, has been detected in sensory neurons of dorsal root and trigeminal ganglion (DRG, TG) and skin cells (e.g. keratinocytes, mast cells, and macrophages). Recent evidence from experimental and clinical relevant studies has implicated that TRPV4 in skin cells plays an important role in both acute and chronic itch. In contrast, little is known whether TRPV4 in sensory neurons directly contributes to scratching behaviors. Here we used sensory neuron-Trpv4 conditional knockout (cKO) mice to address this question. Our results showed that TRPV4 in sensory neurons contributes to scratching behavior evoked by histaminergic (histamine and 48/80) and partial histaminergic (5-HT), but not non-histaminergic (SLIGRL and CQ) pruritogens. Moreover, we observed that TRPV4 in sensory neurons is required for dry skin, but not allergic contact dermatitis, -associated chronic itch. These findings suggest that neuronal-TRPV4 might be specific for some forms of acute and chronic itch.