PI3K/Akt信号通路和HCN通道参与慢性疼痛的信号机制研究

Chronic pain is a significant public health and economic problem in the worldwide. However, many critical steps in this pain pathogenesis are not fully understood. Recent results demonstrate that hyperpolarization-activated and cyclic nucleotide-gated cation (HCN) channels play a central role both in inflammatory and neuropathic pain. Besides, PI3K/Akt signaling pathway is also involved in inflammatory and neuropathic pain, both through the periphery and the central nervous mechanism. We are particularly interested in understanding the interaction mechanisms between HCN channels and PI3K/Akt signaling pathway. Using molecular biology, patch clamping, western blot and immunofluorescence, we try to understand ⑴ the PI3K/Akt signaling on trafficking and gating mechanism on HCN channels; ⑵ effect of PI3K/Akt to different biophysical properties of HCN channels (HCN1~HCN4); ⑶ how effect of PI3K/Akt on HCN channels involved in pain sensitization. The successful implementation of this project will first reveal the influence of PI3K/Akt signaling on HCN channels function, more importantly, this study will help to further understand the molecular mechanisms in pain pathogenesis, so provide both experimental and theoretical basis for future pain treatment.

慢性疼痛严重影响着人民群众的身心健康，是全球性的公共卫生与经济问题。慢性疼痛的发病原因复杂，分子机制尚不清晰。近年来研究表明超极化激活环核苷酸门控阳离子（HCN）通道和PI3K/Akt信号通路在炎性痛和神经病理痛中均扮演重要角色。本项目拟探索二者之间的相互作用及分子机制，包括采用分子生物学、全细胞膜片钳、Western blot及免疫荧光等方法在异源表达系统和背根神经节神经元中研究PI3K/Akt对HCN通道的调控作用。我们将系统评价PI3K/Akt对HCN通道上膜转运和门控的调节，研究PI3K/Akt对HCN通道不同亚型的功能影响，并探索PI3K/Akt对HCN通道的调节与疼痛发生的相关性。本项目的成功实施，将首次揭示PI3K/Akt对HCN通道的功能影响，更重要得是，该研究将帮助我们进一步理解疼痛发生发展的分子机制，为今后疾病治疗提供实验和理论基础。

近年来研究表明HCN通道和PI3K/Akt信号通路在炎性痛和神经病理痛中均扮演重要作用，本项目主要探索了PI3K信号通路对HCN通道功能的调控。研究通过过表达PI3K或激活IGF1R信号通路等方法调控胞内PI3K信号通路，结合免疫荧光和电生理学实验，发现PI3K显著调控HCN通道功能，表现为通道上膜量、电流密度和电压敏感性的改变。而PIP2（PI3K上游重要磷脂分子）对HCN通道的调控微弱；因此，PI3K可能主要通过下游信号调控HCN通道功能。该研究另外发现卡维地洛是一个HCN通道的负性门控调节剂，该发现可解释卡维地洛在治疗心衰方面优越于其他β受体阻滞剂的机制。另外，该项目发现了系列HCN通道抑制剂，结构新颖，抑制效果强于已上市的药物HCN抑制剂Ivabradine。