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

项目摘要/摘要： 角膜疼痛是检测损伤或损害的重要机制，导致保护性反应 尽可能限制损伤(撕裂以取出异物)，开始愈合并保护眼表 需要有清晰的视野。当适应不良时，角膜疼痛可能会使人虚弱，从而限制日常功能， 极大地降低了生活质量，造成了重大的经济负担。人们有相当大的理解 痛觉的分子和细胞基础对机械、化学和 热刺激，但光影响角膜损伤后疼痛(光敏)的能力不佳 明白了。越来越多的证据表明，光过敏使用表达黑素的三叉神经节 感觉神经元除了经典的视网膜通路外，还有这些三叉神经节神经元 对角膜机械敏感有贡献。在这项提案中，关于这一类人如何 三叉神经细胞在正常和致敏的疾病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，黑素在C纤维(热纤维和化学纤维)和Ad纤维(压力纤维)中都有表达。 感知鼠和人的三叉神经细胞，其中一些共同表达CGRP。这些黑色素- 正常和病理生理状态下表达的神经元与角膜机械和光敏有关 条件，并能在体外对光做出反应。最后，视神经不是行为测量所必需的。 三叉神经敏化模型中的光敏感性。因此，假设含有黑色素的角膜 三叉神经细胞直接调节角膜机械敏感度和光敏感度 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。目标1将评估成人和发育中的角膜神经支配 在缺乏黑素表达的三叉神经细胞中的阶段以确定这些机制 小鼠的角膜机械敏感性降低。目的2将评估黑素的表达能力 角膜神经通过改变一种具有代表性的神经肽的分泌来改变机械和光敏感性 对光有反应的正常和敏感型角膜。目标3将评估哪些三叉神经节神经元(C- 在角膜疾病、损伤或敏化的模型中，Ad的纤维有助于机械和光敏。 预期的结果将阐明分子、细胞、解剖学和神经生物学机制。 正常和病理生理状态下的角膜神经支配、疼痛和光过敏。

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.