Role of Nociceptor Primary Cilia in Inflammatory and Neuropathic Pain

初级纤毛是从几乎所有的细胞表面突出的短毛状结构。 脊椎动物的身体。在神经系统中，纤毛对发育和功能都至关重要。 神经元，包括脊髓、大脑皮层、海马体、黑质纹状体系统，以及 小脑。背根神经节(DRG)的感觉神经元构成单一的初级 纤毛位于胞体后不久，在胚胎发育中并迁移到背根节. 然而，对初级纤毛可能具有的潜在功能知之甚少。 成熟的背根节神经元。最近在果蝇和老鼠身上的研究表明刺猬扮演了一个角色 伤害性敏感化中的信号传递。在哺乳动物中，刺猬途径展示了一种 依赖初级纤毛进行信号转导。这项研究提案试图测试 DRG伤害性神经元表达的初级纤毛调节伤害性感受的假说 从外周到达的信号，从而在正常情况下调制伤害性信号 生理状态和病理生理状态。在具体目标1中，我们将 研究初级纤毛在痛阈值和炎性和慢性炎症模型中的重要性。 大鼠和小鼠模型中的神经病理性疼痛。在具体目标2中，我们将测试 Hedghog信号在调节PIPN的阈值、炎症和慢性疼痛状态中的作用 我们将研究Hedgehog信号对DRG神经元初级纤毛的依赖性。 目的2检验Hedgehog信号在两者中介导痛敏的假说。 炎症和PIPN疼痛状态。在大鼠中靶向初级纤毛特异性鞭毛内的siRNA 转运蛋白(IFT)基因将通过鞘内注射的方式注入腰背根节。SiRNA- 这些基因的介导性敲除会导致初级睫毛功能的丧失。在……里面 小鼠，表达整合到NaV1.8基因座中的Cre重组酶的敲入线应 作为一种工具，特异性地消除伤害性神经元中的IFT基因Ift88。 PIPN和Hedgehog信号通路的药理学和siRNA修饰 基因敲除和野生型大鼠，以及功能丧失和功能获得突变的小鼠 应使用初级纤毛和刺猬信号。这个项目的意义在于 我们将阐明Hedgehog作为一种新的信号转导途径来改变慢性粒细胞白血病 疼痛状态，以及疼痛作用的部位，即初级纤毛。纤毛和纤毛 Hedgehog通路提供了多个可用药的靶点，这些靶点可能被证明是适合翻译成 疼痛治疗的新疗法。

Primary cilia are short hair-like structures protruding from the surface of almost all cells in the vertebrate body. In the nervous system, cilia are critical for both the development and the function of neurons, including in spinal cord, cerebral cortex, hippocampus, the nigrostriatal system, and the cerebellum. Sensory neurons of the dorsal root ganglia (DRG) elaborate a single primary cilium at their soma shortly after they are born in embryogenesis and migrate into the DRG. However, nothing is known about potential functions that primary cilia may have in the function of mature DRG neurons. Recent work in the fruit fly and in the rat have shown a role for Hedgehog signaling in nociceptive sensitization. In mammals, the Hedgehog pathway demonstrates a dependence upon primary cilia for signal transduction. This research proposal seeks to test the hypothesis that primary cilia expressed by nociceptive neurons of the DRG modulate nociceptive signals arriving from the periphery and thereby modulate nociceptive signaling under normal physiological conditions and during pathophysiological states. In Specific Aim 1 we shall investigate the importance of primary cilia in pain thresholds and in models of inflammatory and neuropathic pain in both rat and mouse models. In Specific Aim 2 we shall test the role of Hedghog signalling in the modulation of threshold, inflammatory, and chronic pain states in PIPN, and we shall examine the dependence of Hedgehog signalling upon primary cilia of DRG neurons. Aim 2 examines the hypothesis that Hedgehog signaling mediates hyperalgesia in both inflammatory and PIPN pain states. In the rat, siRNA targeting primary cilium-specific intraflagellar transport (IFT) genes will be administered to lumbar DRGs through intrathecal injection. siRNA- mediated knockdown of these genes specifically leads to a loss of the primary ciliary function. In the mouse, knock-in lines expressing a Cre recombinase integrated into the NaV1.8 locus shall be used as a tool to specifically eliminate the IFT gene Ift88 in nociceptive neurons. Pharmacological and siRNA-based modification of PIPN and Hedgehog signaling in both knockdown and wildtype rats, as well as loss-of-function and gain-of-function mouse mutants in primary cilia and in Hedgehog signaling, shall be employed. The significance of this project is that we shall elucidate Hedgehog as a new signal transduction pathway for the modification of chronic pain states, and also the locus at which it acts, the primary cilium. Both the cilium and the Hedgehog pathway offer multiple druggable targets that may prove amenable for translation into novel therapeutics for pain therapy.