Corneal wound healing and nerve regeneration

摘要 角膜神经对角膜健康和保护眼睛免受外界因素的影响非常重要。他们是 主要是伤害性反应，编码对机械刺激、温度和/或疼痛的不适和疼痛 化学刺激。疾病、感染和眼科手术都会损害角膜神经，并长期存在 其后果包括疼痛、干眼、反复侵蚀、浑浊甚至失明。然而，目前还没有 一旦发生纤维化，对神经功能障碍的有效临床治疗。我们之前的工作使我们能够更好地 了解人和猫大创面中肌成纤维细胞分化的控制因素 眼角膜。这项工作还导致观察到伤口肌成纤维细胞和 再生的角膜神经。用抗纤维化药物对伤口进行预处理可以缓解这一问题， 但在大多数意外损伤或感染的情况下，患者出现在肌成纤维细胞分化/纤维化之后 已经发生了。因此，问题不再是预防纤维化，而是克服接触抑制 神经和持续性肌成纤维细胞之间的联系。我们最近发现PPARg配体曲格列酮 在体外和体内刺激轴突生长并导致肌成纤维细胞去分化。重要的是 这些效应可以通过一种不使用PPARg并以线粒体为靶点的化合物在体外模拟 丙酮酸载体(MPC)。与最近的文献一起，我们的试点数据构成了批判性测试的强有力的前提 假设抑制MPC可能促进再生神经和神经的代谢重建 活化的肌成纤维细胞克服角膜损伤后期固有的神经再支配障碍 纤维化症。为了验证这一假设，我们将：目标1，确定代谢变化，通过抑制 线粒体丙酮酸转运促进外周感觉神经元突起生长 创伤环境；目标2，评估是相似还是不同的机制(如目标1)是去分化的基础 目的3，比较不同线粒体调节剂对角膜成纤维细胞的相对作用。 克服肌成纤维细胞对角膜神经再生的抑制作用。从根本上说，拟议的 研究将确定MPC活性是否是克服纤维化和/或其相关的轴突抑制的关键 外延生长。我们将通过基因组操作确认角膜成纤维细胞和 外周感觉神经元，确定靶向如何影响线粒体功能，并识别信号 在调节这些效应所必需的新陈代谢重排的下游。因为货币政策委员会从来没有 在周围创伤的背景下进行研究，我们的结果可能揭示其新的、广泛相关的方面 功能。最终，这项拟议的研究旨在揭开可能发挥作用的新的分子机制 在大的、已建立的、纤维性伤口中发挥重要的、迄今未被探索的作用。对这些机制的定义如下 如果我们要开发新的疗法来治疗成熟的角膜创伤，那么就有必要这样做 促进最佳神经再生，确保角膜长期健康和透明。

Abstract Corneal nerves are important for cornea health, and for protecting the eye from outside elements. They are mostly nociceptive, coding discomfort and pain in response to mechanical stimulation, temperature and/or chemical stimulation. Disease, infection and ocular surgery all damage corneal nerves, with long-term consequences in terms of pain, dry eye, recurrent erosions, opacity and even blindness. Yet, there are no effective clinical therapies for nerve dysfunction once fibrosis has occurred. Our prior work allowed us to better understand factors that control myofibroblast differentiation in the large wounds generated in human and cat corneas. This work also led to the observation of a nefarious interaction between wound myofibroblasts and regenerating corneal nerves. Pre-treating the wound area with anti-fibrotic agents can mitigate this problem, but in most cases of accidental injury or infection, patients present after myofibroblast differentiation/fibrosis have occurred. The issue then is no longer preventing fibrosis, but rather overcoming the contact inhibition between nerves and persistent myofibroblasts. We recently found that the PPARg ligand Troglitazone stimulates neurite outgrowth and causes myofibroblasts de-differentiation in vitro and in vivo. Importantly, these effects can be mimicked in vitro by a compound that spares PPARg and targets the mitochondrial pyruvate carrier (MPC). Together with recent literature, our pilot data form a strong premise for critically testing the hypothesis that inhibiting the MPC may facilitate metabolic remodeling in both regenerating nerves and activated myofibroblasts to overcome the blocked reinnervation inherent in later stages of post-injury corneal fibrosis. To test this hypothesis, we will: Aim 1, identify metabolic changes through which inhibiting mitochondrial pyruvate transport promotes neurite outgrowth of peripheral sensory neurons in a simulated wound environment; Aim 2, assess if similar or different mechanisms (as in Aim 1) underlie de-differentiation of corneal myofibroblasts; and Aim 3, contrast the relative efficacy of different mitochondrial modulators for overcoming myofibroblasts’ inhibition on corneal nerve regeneration in vivo. Fundamentally, the proposed research will ascertain if MPC activity is key to overcoming fibrosis and/or its associated inhibition of neurite outgrowth. We will confirm target specificity through genome manipulation in both corneal fibroblasts and peripheral sensory neurons, determine how targeting impacts mitochondrial function, and identify signals downstream of metabolic rewiring that are necessary to mediate these effects. Since the MPC has never been studied in the context of peripheral wounding, our results could unveil new, broadly-relevant aspects of its function. Ultimately, the proposed research aims to unravel novel molecular mechanisms that may play a substantial, hitherto unexplored role in large, established, fibrotic wounds. Defining these mechanisms is necessary if we are to develop new therapies for the treatment of mature corneal wounds with an eye to promoting optimal nerve regeneration and ensuring long-term corneal health and clarity.