Therapeutic inhibition of keratinocyte TRPV3 sensory channel by local anesthetic dyclonine

Abstract

The multimodal sensory channel transient receptor potential vanilloid-3 (TRPV3) is expressed in epidermal keratinocytes and implicated in chronic pruritus, allergy, and inflammation-related skin disorders. Gain-of-function mutations of TRPV3 cause hair growth disorders in mice and Olmsted Syndrome in human. We here report that mouse and human TRPV3 channel is targeted by the clinical medication dyclonine that exerts a potent inhibitory effect. Accordingly, dyclonine rescued cell death caused by gain-of-function TRPV3 mutations and suppressed pruritus symptoms in vivo in mouse model. At the single-channel level, dyclonine inhibited TRPV3 open probability but not the unitary conductance. By molecular simulations and mutagenesis, we further uncovered key residues in TRPV3 pore region that could toggle the inhibitory efficiency of dyclonine. The functional and mechanistic insights obtained on dyclonine-TRPV3 interaction will help to conceive updated therapeutics for skin inflammation.

Molecular determinants for the chemical activation of the warmth-sensitive TRPV3 channel by the natural monoterpenoid carvacrol

“…Heat at 42 °C activates TRPV3 with a unitary conductance at 146 ± 7 pS (36,37). Chemical activation of TRPV3 by 2-APB in the presence or absence of TRPV3 inhibitor dyclonine also reveals a different unitary conductance of 179.2 ± 5.5 pS and 163.6 ± 6.4 pS, respectively (38). In this study, our single-channel recordings of TRPV3 activation by carvacrol and 2-APB at voltages ranging from -80 mV to +80 mV show a unitary conductance of 182.0 ± 6.4 pS and 173.2 ± 5.3 pS, respectively.…”

“…Multimodal TRPV3 exhibits different unitary conductances in response to chemical or heat stimulation (36)(37)(38). Heat at 42 °C activates TRPV3 with a unitary conductance at 146 ± 7 pS (36,37).…”

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

“…Scu may jam the movement of pore helix and S6 required for channel opening (Deng et al, 2020; Shimada et al, 2020) and thereby inhibit the TRPV3 channel activity. The same pocket has also been suggested to be critical for the inhibitory action of dyclonine (Liu et al, 2021) and 2,6‐dimethoxy‐ N ‐(4‐(4‐[trifluoromethyl] phenyl)oxazol‐2‐yl)benzamide (Zhang et al, 2021), suggesting it being a functional “hotspot” to channel gating and allosteric negative modulation of TRPV3. This common binding pocket differs from the two cavities bound by osthole, which are formed by the S1‐S4 bundle and the TRP helix as well as the nexus of the linker domain and pre‐S1 and TRP helices of TRPV3 (Deng et al, 2020; Singh et al, 2018; Zubcevic & Borschel, 2019).…”

In vitro models for investigating itch

“…Following stimulation, some ion channels and receptors provide an immediate readout (e.g., changes in [Ca 2+ ] following TRP channel activation), and thus transfected cells of non-neuronal origin provide a straightforward method for investigating ion channel or receptor function and running screening assays of potential antagonists. For example, as discussed previously, TRPV3 is implicated in pruritus and its expression in HEK293T cells has provided a successful means for identifying inhibitors, such as the oral anesthetic dyclonine (found in throat sprays and lozenges), and the tropical plant-based acridone citrusinine-II ( Han et al, 2021 ; Liu et al, 2021 ). Other cell lines naturally express itch related receptors, for example, HaCaT cells endogenously express PAR2 ( Castex-Rizzi et al, 2014 ).…”