Journal club 26. 07. 10

A specialized population of hair afferents dedicated to transmitting mechanical itch

Neuron  2026 Jun 4:S0896-6273(26)00409-5. doi: 10.1016/j.neuron.2026.05.017.

Mahar Fatima,1,9 Hankyu Lee,1,9 Hwayeon Cha,1,9 Chia Chun Hor,1 Feng Wang,2 Jingyi Liu,1 Jonathan Damblon,2 Wenwen Zhang,3 Katie Qu,1 Yumena Nagai,1 Abbey Dinh,1 Ziyan Wu,1 Ranveer Ajimal,1 Ailin Emily Xiong,1 Madeleine Chai,1 Alyssa Asmar,1 Wei Cai,3,6 Xiaowei Zhou,1 Anuraag Balaji,4 Haili Pan,1,7 Lorraine Horwitz,1 Lam C. Tsoi,4 Hongzhen Hu,5 X. Z. Shawn Xu,3,8 Yves De Koninck,2 and Bo Duan1,10,

*Correspondence: bduan@umich.edu

SUMMARY
Hairs serve as sensory structures that are crucial for perceiving environmental cues through interactions with
sensory endings. Depigmented and demedullated atypical hairs exhibit a limited distribution on mammalian
skin and have not been extensively studied. In this study, we identify a specific type of hair, termed vellus-like
hairs (VLHs), which are enriched in the postauricular region and on the hindpaws of mice. These hairs are
innervated by Aβ low-threshold mechanoreceptors (LTMRs) that co-express Toll-like receptor 5 and Calbindin1
(TLR5Calb1). Genetic ablation or silencing of these hair afferents eliminated mechanical itch generated by
gentle VLH stroking or indentation under both physiological and pathological conditions. Conversely, optogenetic
activation of TLR5Calb1 hair afferents evoked itch behaviors. Mechanosensitive Piezo2 channels in
TLR5Calb1 Aβ-LTMRs function as key mechanotransducers for mechanical itch signaling. Our study sheds
light on the previously poorly understood somatosensory physiology of unique hairs, emphasizing the significant
role of TLR5Calb1 Aβ-LTMRs in itch transmission.