Patch-seq of mouse DRG neurons reveals candidate genes for specific mechanosensory functions

Thibaud Parpaite, Lucie Brosse, Nina Se´ journe´ , Amandine Laur, Yasmine Mechioukhi, Patrick Delmas, Bertrand Coste

Abstract

A variety of mechanosensory neurons are involved in touch, proprioception, and pain. Many molecular components of the mechanotransduction machinery subserving these sensory modalities remain to be discovered. Here, we combine recordings of mechanosensitive (MS) currents in mechanosensory neurons with single-cell RNA sequencing. Transcriptional profiles are mapped onto previously identified sensory neuron types to identify cell-type correlates between datasets. Correlation of current signatures with single-cell transcriptomes provides a one-to-one correspondence between mechanoelectric properties and transcriptomically defined neuronal populations. Moreover, a gene-expression differential comparison provides a set of candidate genes for mechanotransduction complexes. Piezo2 is expectedly found to be enriched in rapidly adapting MS current-expressing neurons, whereas Tmem120a and Tmem150c, thought to mediate slowtype MS currents, are uniformly expressed in all mechanosensory neuron subtypes. Further knockdown experiments disqualify them as mediating MS currents in sensory neurons. This dataset constitutes an open resource to explore further the cell-type-specific determinants of mechanosensory properties.

Presenter: Hye In Kim

miRNA-203b-3p induces acute and chronic pruritus via 5-HTR2B and TRPV4

Francesco De Logu, Roberto Maglie, Mustafa Titiz, Giulio Poli, Lorenzo Landini, Matilde Marini, Daniel Souza Monteiro de Araujo, Gaetano De Siena, Marco Montini, Daniela Almeida Cabrini, Michel Fleith Otuki, Priscila Lúcia Pawloski, Emiliano Antiga, Tiziano Tuccinardi, João Batista Calixto, Pierangelo Geppetti, Romina Nassini, Eunice André

Abstract

Growing evidence indicates that transient receptor potential (TRP) channels contribute to different forms of pruritus. However, the endogenous mediators that cause itch via TRP channels signaling are poorly understood. Herein, we show that genetic deletion or pharmacological antagonism of TRP vanilloid 4 (TRPV4) attenuated itch in a mouse model of psoriasis induced by topical application of imiquimod. Human psoriatic lesions showed increased expression of several miRNAs, including the miR-203b-3p, which induced a Ca²⁺ response in rodent dorsal root ganglion neurons and scratching behavior in mice via serotonin receptor 2B (5-HTR2B) activation and the protein kinase C-dependent phosphorylation of TRPV4. Computer simulation revealed that the miR-203b-3p core sequence (GUUAAGAA) that causes 5-HTR2B/TRPV4-dependent itch, targets the extracellular side of 5-HTR2B by interacting with a portion of the receptor pocket consistent with its activation. Overall, we reveal the unconventional pathophysiological role of an extracellular miRNA that can behave as an itch promoter via 5-HTR2B and TRPV4.

Keywords: itch; miRNA; neurons; scratching behavior; skin diseases.

Scutellarein attenuates atopic dermatitis by selectively inhibiting transient receptor potential vanilloid 3 channels

Yujing Wang1 | Liaoxi Tan1 Shan Jiang1 | Younan Ren1 Khalid N. M. Abdelazeem4 | Zhengyu Cao1

| Kejun Jiao1 | Chu Xue1 | Qinglian Tang1 | | Hao Chen2 | Tarek Mohamed Abd El-Aziz3 |

Ye Yu5 | Fang Zhao1 | Michael X. Zhu6 |
1State Key Laboratory of Natural Medicines and Department of TCM Pharmacology, School of Traditional Chinese Pharmacy, China Pharmaceutical University,

Nanjing, China
2Institute of Dermatology, Chinese Academy of Medical Sciences & Peking Union Medical College, Nanjing, China
3Zoology Department, Faculty of Science, Minia University, El-Minia, Egypt
4Radiation Biology Research Department, National Centre for Radiation Research and Technology, Atomic Energy Authority, Cairo, Egypt
5Department of Basic Medicine, School of Basic Medicine and Clinic Pharmacy, China Pharmaceutical University, Nanjing, China
6Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas, USA

Background and Purpose: Atopic dermatitis (AD) is one of the most common chronic inflammatory cutaneous diseases with unmet clinical needs. As a common ingredient found in several medicinal herbs with efficacy on cutaneous inflammatory diseases, Scutellarein (Scu) has been shown to possess anti-inflammatory and anti-proliferative activities. We aimed to evaluate the therapeutic efficacy of Scu against AD and its underlying molecular mechanism.

Experimental Approach: Efficacy of Scu on AD was evaluated in 2,4-dinitrofluorobenzene (DNFB) and carvacrol-induced dermatitis mouse models. Cytokine mRNA and serum IgE levels were examined using qPCR and ELISA, respec- tively. Voltage clamp recordings were used to measure currents mediated by tran- sient receptor potential (TRP) channels. In silico docking, site-direct mutagenesis, and covalent modification were used to explore the binding pocket of Scu on TRPV3.

Key Results: Subcutaneous administration of Scu efficaciously suppresses DNFB and carvacrol-induced pruritus, epidermal hyperplasia and skin inflammation in wild type mice but has no additional benefit in Trpv3 knockout mice in the carvacrol model. Scu is a potent and selective TRPV3 channel allosteric negative modulator with an appar- ent affinity of 1.18 μM. Molecular docking coupled with site-direct mutagenesis and covalent modification of incorporated cysteine residues demonstrate that Scu targets the cavity formed between the pore helix and transmembrane helix S6. Moreover, Scu attenuates endogenous TRPV3 activity in human keratinocytes and inhibits carvacrol-induced proliferative and proinflammatory responses.

Conclusion and Implications: Collectively, these data demonstrate that Scu amelio- rates carvacrol-induced skin inflammation by directly inhibiting TRPV3, and TRPV3 represents a viable therapeutic target for AD treatment.

KEYWORDS

atopic dermatitis, keratinocytes, scutellarein, TRPV3

PIEZO1 transduces mechanical itch in mice

Rose Z Hill ¹, Meaghan C Loud ¹, Adrienne E Dubin ², Brooke Peet ¹, Ardem Patapoutian ³

¹Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, USA.

²Department of Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, USA.

³Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, USA. ardem@scripps.edu.

Abstract

Itch triggers scratching, a behavioural defence mechanism that aids in the removal of harmful irritants and parasites¹. Chemical itch is triggered by many endogenous and exogenous cues, such as pro-inflammatory histamine, which is released during an allergic reaction¹. Mechanical itch can be triggered by light sensations such as wool fibres or a crawling insect². In contrast to chemical itch pathways, which have been extensively studied, the mechanisms that underlie the transduction of mechanical itch are largely unknown. Here we show that the mechanically activated ion channel PIEZO1 (ref. ³) is selectively expressed by itch-specific sensory neurons and is required for their mechanically activated currents. Loss of PIEZO1 function in peripheral neurons greatly reduces mechanically evoked scratching behaviours and both acute and chronic itch-evoked sensitization. Finally, mice expressing a gain-of-function Piezo1 allele⁴ exhibit enhanced mechanical itch behaviours. Our studies reveal the polymodal nature of itch sensory neurons and identify a role for PIEZO1 in the sensation of itch.

https://www.nature.com/articles/s41586-022-04860-5#additional-information

Presenter: Hyein Kim