Molecular, cellular, anatomical and neurobiological investigation of melanopsin-expressing corneal innervation, and its role in pain and photophobia

项目概要/摘要： 角膜疼痛是检测损伤或损害的重要机制，导致对角膜的保护性反应。 尽可能减少损伤（撕裂以清除异物），促进愈合并保护眼表 需要清晰的视野。当适应不良时，角膜疼痛会使人虚弱，从而限制日常功能， 大大降低生活质量，并造成重大的经济负担。有相当多的理解 疼痛感知的分子和细胞基础对机械，化学和 热刺激，但角膜损伤后光影响疼痛（光异常性疼痛）的能力不佳 明白越来越多的证据表明光异常性疼痛使用表达黑素蛋白的三叉神经节 感觉神经元除了经典的视网膜通路，这些相同的三叉神经节神经元 有助于角膜机械敏感性。在这项建议中，关于这类人如何 三叉神经神经元在正常和疾病的致敏病理生理状态下对角膜疼痛起作用 将讨论角膜表面损伤/干眼病、过敏性眼病和偏头痛的模型。 初步数据显示，黑视蛋白在C纤维（热和化学）和Ad（压力）中表达。 感觉小鼠和人类三叉神经元，其中一些共表达CGRP。这些黑视素- 表达神经元有助于正常和病理生理性角膜机械和光敏感性 条件下，并可以响应光离体。最后，视神经不是行为测量所必需的。 三叉神经致敏模型中的光敏感性。因此，含有黑视蛋白的角膜上皮细胞 三叉神经元的功能是通过直接调节角膜的机械敏感性和光敏感性 有助于角膜神经支配，并使用神经肽调节角膜环境以产生疼痛 将测试感知和敏感度。目的1探讨成人和发育期角膜神经支配的特点 在缺乏黑视蛋白表达的三叉神经元的小鼠中， 小鼠的角膜机械敏感性降低。目的2评价黑视素表达能力 角膜神经通过改变代表性神经肽的分泌来改变机械和光敏感性， 正常和敏感角膜对光的反应。目的3将评估哪些三叉神经节神经元（C- Ad的纤维）在角膜疾病、损伤或致敏模型中有助于机械和光敏感性。 预期的结果将阐明分子，细胞，解剖和神经生物学机制， 正常和病理生理状态下的角膜神经支配、疼痛和光异常性疼痛。

Project Summary/Abstract: Corneal pain is an important mechanism to detect injury or damage, leading to protective responses to limit injury if possible (tearing to remove a foreign object), initiate healing and protect the ocular surface required for clear vision. When maladaptive, corneal pain can be so debilitating as to limit daily function, dramatically reduce quality of life, and cause significant economic burden. There is considerable understanding of the molecular and cellular underpinnings of pain perception in response to mechanical, chemical and thermal stimuli, but the ability of light to influence pain (photoallodynia) after corneal injury is not well understood. Accumulating evidence suggests photoallodynia uses melanopsin-expressing trigeminal ganglia sensory neurons in addition to the classic retinal pathways, and that these same trigeminal ganglia neurons contribute to corneal mechanical sensitivity. In this proposal, the knowledge gap concerning how this class of trigeminal neurons contribute to corneal pain in normal and sensitized pathophysiological states in disease models of corneal surface injury/dry eye disease, allergic eye disease and migraine will be addressed. Preliminary data shows that melanopsin is expressed in both C-fiber (thermal and chemical) and Ad (pressure) sensing mouse and human trigeminal neurons, some of which co-express CGRP. These melanopsin- expressing neurons contribute to corneal mechanical and light sensitivity in normal and pathophysiological conditions, and can respond to light ex vivo. Finally, the optic nerve is not required for behavioral measures of light sensitivity in a model of trigeminal sensitization. Thus the hypothesis that melanopsin-containing corneal trigeminal neurons function to modulate corneal mechanical sensitivity and light sensitivity by directly contributing to corneal innervation, and use neuropeptides to modulate the corneal milieu to effect pain perception and sensitization will be tested. Aim 1 will evaluate corneal innervation in adult and developmental stages in mice lacking melanopsin-expressing trigeminal neurons to identify the mechanism by which these mice have decreased corneal mechanical sensitivity. Aim 2 will evaluate the ability of melanopsin-expressing corneal nerves to alter mechanical and light sensitivity by altering secretion of a representative neuropeptide in normal and sensitized corneas in response to light. Aim 3 will evaluate which trigeminal ganglia neurons (C- fiber of Ad) contribute to mechanical and light sensitivity in models of corneal disease, injury or sensitization. The expected outcomes will elucidate molecular, cellular, anatomical and neurobiological mechanisms of corneal innervation, pain and photoallodynia in normal and pathophysiological states.