外周感觉神经元电压门控氢离子通道Hv1调控炎性疼痛的机制研究

电压门控氢离子通道Hv1是电压门控离子通道超家族的一员。当细胞去极化时，Hv1通道的激活可快速将胞内氢离子运送至胞外。既往研究发现，Hv1在免疫类细胞中表达，并通过调控胞内氢离子稳态参与NADPH氧化酶（NOX）依赖的活性氧（ROS）生成。然而，Hv1在外周感觉神经系统中的表达和功能均未知。我们前期研究意外发现，Hv1在背根神经节巨噬细胞中低表达却在感觉神经元上高表达，并在炎性疼痛模型下进一步大幅上调。功能性研究发现Hv1介导外周感觉神经元上的外向氢离子电流，并且药理抑制Hv1可快速缓解疼痛。Hv1敲除鼠的疼痛敏感性也显著低于对照鼠。本项目中，申请人拟采用新近获得的原创Hv1特异性抑制剂，结合基因敲除鼠、电生理和疼痛神经行为学等技术，深入探究外周感觉神经元上的Hv1通过调控ROS生成及ROS下游分子路径SHP-1-PI3K/Akt参与炎性疼痛发生发展的作用与机制。

Hv1 is a voltage-gated H+ channel belonging to the voltage-gated ion channel superfamily. Upon membrane depolarization, Hv1 rapidly removes H+ from the cytoplasm to the extracellular space. Previous studies suggested that Hv1 is expressed in immune cells and is involved in NADPH oxidase-dependent generation of reactive oxygen species (ROS) via the regulation of intracellular H+ homeostasis. However, the expression and function of Hv1 in the peripheral sensory nervous system remains unknown. Our pilot study found that, in the dorsal root ganglion, Hv1 was found lowly expressed in macrophages but unexpectedly highly expressed in sensory neurons, which was further largely up-regulated upon inflammation. Functional study identified outward H+ currents mediated by Hv1 and rapid analgesic effect by pharmacologically inhibiting Hv1 in mice under inflammatory pain. The pain sensitivity of Hv1 Knockout mice was significantly lower than that in the control mice. By using newly in-house developed selective Hv1 inhibitor, knockout mice, electrophysiology and behavioral tests, this proposal aims to explore the molecular mechanism for neuronal Hv1 in inflammatory pain which likely involves in ROS generation and its downstream SHP-1-PI3K/Akt signaling pathway.