Optopharmacological control of TRPC channels by coumarin-caged lipids is associated with a phototoxic membrane effect

作     者：Oleksandra Tiapko Bernadett Bacsa Gema Guedes de la Cruz Toma Glasnov Klaus Groschner 

作者机构：Institute of BiophysicsMedical University of GrazBio Tech Med-GrazHarrachgasse 21Graz 8010Austria Institute of ChemistryUniversity of GrazNAWI GrazBio Tech Med-GrazHeinrichstrasse 28Graz 8010Austria 

出 版 物：《Science China(Life Sciences)》 (中国科学（生命科学英文版）)

年 卷 期：2016年第59卷第8期

页      面：802-810页

核心收录：

学科分类：0710[理学-生物学] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 07[理学] 071009[理学-细胞生物学] 09[农学] 0901[农学-作物学] 090102[农学-作物遗传育种] 

基　　金：supported by the Austrian Science Fund(FWFW 1226-B18) 

主　　题：caged diacylglycerols TRPC channels Ca2+ signaling optopharmacology 

摘      要：Photouncaging of second messengers has been successfully employed to gain mechanistic insight of cellular signaling path- ways. One of the most enigmatic processes of ion channel regulation is lipid recognition and lipid-gating of TRPC channels, which represents pivotal mechanisms of cellular Ca2＋ homeostasis. Recently, optopharmacological tools including caged lipid mediators became available, enabling an unprecedented level of temporal and spatial control of the activating lipid species within a cellular environment. Here we tested a commonly used caged ligand approach for suitability to investigate TRPC sig- naling at the level of membrane conductance and cellular Ca2＋ handling. We report a specific photouncaging artifact that is triggered by the cage structure coumarin at UV illumination. Electrophysiological characterization identified a light-dependent membrane effect of coumarin. UV light （340 nm） as used for photouncaging, initiated a membrane conductance specifically in the presence of coumarin as low as 30 pmol L-1 concentrations. This conductance masked the TRPC3 conductance evoked by photouncaging, while TRPC-mediated cellular Ca2＋ responses were largely preserved. The observed light-induced membrane effects of the released caging moiety may well interfere with certain cellular functions, and prompt caution in using couma- fin-caged second messengers in cellular studies.