Yalan Han1,2, Anna Luo1,2, Peter Muiruri Kamau1,2,3, Pitchayakarn Takomthong4, Jingmei Hu5, Chantana Boonyarat4, Lei Luo1, Ren Lai1,3,6. 1. Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Kunming, China. 2. University of Chinese Academy of Sciences, Beijing, China. 3. Sino-African Joint Research Center, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China. 4. Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, Thailand. 5. College of Life Sciences, Nanjing Agricultural University, Nanjing, China. 6. KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, National Resource Center for Non-Human Primates, Kunming Primate Research Center and National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Institute of Zoology, Kunming, China.
Abstract
BACKGROUND AND PURPOSE: Itching is the most frequent pathology in dermatology that has significant impacts on people's mental health and social life. Transient receptor potential vanilloid 3 (TRPV3) channel is a promising target for treating pruritus. However, few selecetive and potent antagonists have been reported. This study was designed to identify selective TRPV3 antagonist and elucidate its anti-pruritus pharmacology. EXPERIMENTAL APPROACH: FlexStation and calcium fluorescence imaging were conducted to track the functional compounds. Whole-cell patch clamp was used to record itch-related ion channel currents. Homologous recombination and site-directed mutagenesis were employed to construct TRPV3 channel chimeras and point mutations for exploring pharmacological mechanism. Mouse models were used for in vivo anti-pruritus assay. KEY RESULTS: An acridone alkaloid (citrusinine-II) was purified and characterized from Atalantia monophylla. It directly interacts with Y564 within S4 helix of TRPV3 to selectively inhibit the channel with a half maximal inhibitory concentration (IC50 ) of 12.43 μM. Citrusinine-II showed potential efficacy to attenuate both chronic and acute itch. Intradermal administration of citrusinine-II (143 ng/skin site) nearly completely inhibited itch behaviours. It also shows significant analgesic effects. Little side effects of the compound are observed. CONCLUSION AND IMPLICATIONS: By acting as a selective and potent inhibitor of TRPV3 channel, citrusinine-II shows valuable therapeutic effects in pruritus animal models and is a promising candidate drug and/or lead molecule for the development of anti-pruritus drugs.
BACKGROUND AND PURPOSE: Itching is the most frequent pathology in dermatology that has significant impacts on people's mental health and social life. Transient receptor potential vanilloid 3 (TRPV3) channel is a promising target for treating pruritus. However, few selecetive and potent antagonists have been reported. This study was designed to identify selective TRPV3 antagonist and elucidate its anti-pruritus pharmacology. EXPERIMENTAL APPROACH: FlexStation and calcium fluorescence imaging were conducted to track the functional compounds. Whole-cell patch clamp was used to record itch-related ion channel currents. Homologous recombination and site-directed mutagenesis were employed to construct TRPV3 channel chimeras and point mutations for exploring pharmacological mechanism. Mouse models were used for in vivo anti-pruritus assay. KEY RESULTS: An acridone alkaloid (citrusinine-II) was purified and characterized from Atalantia monophylla. It directly interacts with Y564 within S4 helix of TRPV3 to selectively inhibit the channel with a half maximal inhibitory concentration (IC50 ) of 12.43 μM. Citrusinine-II showed potential efficacy to attenuate both chronic and acute itch. Intradermal administration of citrusinine-II (143 ng/skin site) nearly completely inhibited itch behaviours. It also shows significant analgesic effects. Little side effects of the compound are observed. CONCLUSION AND IMPLICATIONS: By acting as a selective and potent inhibitor of TRPV3 channel, citrusinine-II shows valuable therapeutic effects in pruritus animal models and is a promising candidate drug and/or lead molecule for the development of anti-pruritus drugs.