TRPV1 SUMO/deSUMO修饰调控膜转运及其在痛觉调控中的作用

TRPV1 sensitization is associated with its phosphorylation and plays a key regulator of pain perception, but the underlying cellular mechanism has remained unclear. Our preliminary study has shown that TRPV1 undergoes SUMO modification and is deSUMOylated by SENP1. TRPV1 SUMO alters its surface expression and promotes its phosphorylation. Deletions of SENP1 in DRG neurons lead to hyper-sumoylation of the proteins within the tissues and exhibit exaggerated inflammatory thermal hyperalgesia induced by carrageenan. Based on our published work and extensive preliminary data, our hypothesis is that TRPV1 SUMO/deSUMO regulates its trafficking and participates in the inflammation-induced hyperalgesia via a possible interplay between phosphorylation and sumoylation of TRPV1. Our aims are to: 1. Define how TRPV1 SUMO/deSUMO regulates the biophysical properties of the channels. 2. Determine how TRPV1 SUMO/deSUMO modulates its trafficking. 3. Characterise the functional crosstalk and complex interplay between different TRPV1 PTMs. 4. Elucidate the molecular and cellular mechanisms of the TRPV1 SUMO/deSUMO on the inflammation-induced hyperalgesia. The expected result of this project will provide clear mechanistic insight into how TRPV1 SUMO/deSUMO regulates its gating, membrane trafficking, the interplay between TRPV1 PTMs and is involving changes in nociceptive signaling events and lead to enhanced pain sensations (hyperalgesia). The project will not only advance our knowledge on the underlying mechanism of inflammatory hyperalgesia, but also help us identify potential targets for pain treatment.

TRPV1磷酸化调控通道敏化，从而在痛觉感受中作为重要的调控因子，但是其细胞分子机制却不清楚。预实验结果表明，TRPV1可被SUMO修饰并受SENP1调控。TRPV1 SUMO修饰改变其膜表达和促进其磷酸化。DRG神经元敲除SENP1基因，TRPV1 SUMO化增高，小鼠表现为痛敏增强的表型。据此,提出科学假说：TRPV1 SUMO/deSUMO修饰调控其膜转运，通过其与磷酸化修饰相互作用参与痛敏的调控。科学问题包括：1. 确定TRPV1 SUMO/deSUMO调控通道的门控和调节；2. 确定TRPV1 SUMO/deSUMO调控其膜转运机制；3. 明确TRPV1 PTMs间的相互作用；4. TRPV1 SUMO/deSUMO调控痛敏的分子基础。阐明SUMO/deSUMO在门控、膜转运和PTMs间的相互作用及其在痛觉敏化中的作用和机制，对于揭示和理解其在痛敏调控的作用具有理论价值。

TRPV1磷酸化调控通道敏化，从而在痛觉感受中作为重要的调控因子，但是其细胞分子机制却不清楚。我们的研究发现：1) 背根神经节初级感觉神经元SUMO1以及SENP1蛋白（去SUMO化修饰蛋白酶）表达丰富；2) TRPV1 通道能够被SUMO 修饰，并且SUMO修饰发生于K822 位点；3) TRPV1 SUMO修饰提高对温度的敏感性，但不影响电压，酸和激动剂的敏感性；4) TRPV1 通道SUMO修饰促进TRPV1 的上膜过程，并且促进其磷酸化，但是其与TRPV1的糖基化无关；5) DRG 神经元SENP1 基因条件性敲除小鼠，表现为痛敏增强的表型。为了进一步探索PKCε在热痛敏化中的作用, 研究PKCε 与TRPV1 SUMO修饰在炎性疼痛中的相互作用及其机制：1）发现PKCε能够发生SUMO化修饰并鉴定其SUMO修饰的位点；2）发现PKCε磷酸化修饰是为其自身SUMO化修饰的先决条件,即SUMO化修饰依赖其磷酸化修饰的调控机制；3）发现PKCεSUMO修饰能够增强PKCε稳定性、活性及其与底物蛋白TRPV1的结合化；4）发现PKCεSUMO修饰缺失可降低小鼠急/慢性炎症热痛反应。阐明SUMO/deSUMO在门控、膜转运和PTMs间的相互作用及其在痛觉敏化中的作用和机制，对于揭示和理解其在痛敏调控的作用具有理论价值。