温度敏感TRP离子通道异源组装的分子机制及功能研究

As polymodal receptors, temperature-sensitive transient receptor potential (TRP) ion channels can detect a variety of environmental stimuli. It is generally hypothesized that heteromeric assembly of temperature-sensitive TRP channels underlines the molecular basis of fine-tuning of temperature sensation and chemical activation. Our proposed study aims to investigate the heteromeric assembly between temperature-sensitive TRP channels and the functional properties of heteromaric channels. Our recent studies demonstrated that co-expression of TRPV1 and TRPV3 subunits yielded heteromeric channels with distinct temperature sensitivity, activation threshold and heat-induced sensitization. This new finding suggests that the heteromeric assembly may play an important role in sensitive-detecting of temperature and fine-tuning of temperature sensation. Moreover, our prelimilary data showed that TRPV3 and TRPV4 can bind with each other in vitro and co-expression of TRPV3 and TRPV4 subunits yielded heteromeric channels with intermediate single-channel conductance. Accordingly, this project is to explore the heteromeric assembly between temperature-sensitive TRP channels and clarify the temperature activation properties and pharmacology of the heteromeric channels. This project attempts to reveal the heteromerization between temperature-sensitive TRP channels and investigate the molecular mechanisms of temperature sensation. Hopefully, this project will provide new ideas for exploring the mechanisms of fine-tuning of temperature sensation and diversity of TRP channel function.

温度敏感TRP离子通道作为一种多觉型感受器能够感受多种外界因素的刺激，离子通道亚基间的异源组装促使通道功能多样性，异聚体的形成使机体更敏感地探测内、外界环境细微的变化。因此，探讨温度敏感TRP离子通道的异源组装对阐释其功能多样性及其精细调控温度感觉的分子机理具有重要意义。我们前期研究证实TRPV1/3亚基间的异源组装及异聚体的特定温度激活特性，提示温度敏感TRP离子通道的异源组装在温度连续感受及精细调控过程中扮演着重要的角色。另外，TRPV3/4在体外相互结合，电生理记录到介于两同聚体间的单通道电导，提示TRPV3/4间的异源组装，然而，TRPV3/4异聚体的温度激活特性和药理学特性有待进一步阐明。本项目拟在已有实验基础上对温度敏感TRP离子通道的异源组装及其功能特性进行深入研究，以期探讨其感受温度的机理，为温度感觉精细调控及温度敏感TRP离子通道功能多样性的分子机理提供解释。

温度敏感TRP离子通道作为一种多觉型感受器能够感受多种外界因素的刺激，温度敏感TRP离子通道间的异源组装很可能能够解释温度感觉精细调控及TRP离子通道功能多样性的分子机理。本项目主要探讨了温度敏感TRPV3和TRPV4离子通道间的异源组装及组装后的异聚体通道的电学、温度激活及药理学特性等。本项目研究显示TRPV3和TRPV4能够共表达于HEK293细胞，免疫共沉淀结果显示表达于HEK293细胞及小鼠皮肤组织中的TRPV3和TRPV4蛋白间均具有较强的相互作用；电生理结果显示TRPV3和TRPV4共组装后显示出介于两同聚体通道间的单通道电导，异聚体通道对TRPV3通道的激动剂2-APB敏感性降低，同时异聚体通道温度阈值也介于TRPV3和TRPV4同聚体通道之间，说明温度敏感TRP离子通道异源组装后显示出特定的温度激活特性及药理学特性，很可能是温度连续感受及精细调控的分子机理；另外，我们的结果还显示TRPV3和TRPV4间的异源组装主要由C端介导。本项目的研究揭示了温度敏感TRPV3和TRPV4离子通道间存在异源组装，且呈现出不同于TRPV3及TRPV4同聚体通道的功能特性，为温度感觉精细调控及温度敏感TRP离子通道功能多样性的分子机理提供解释。