Lipid Mediators in Corneal Nerve Regeneration

描述(申请人提供)：角膜手术，包括屈光手术，是最常见的矫正视力的手术之一。据估计，全世界有超过1700万人接受了某种类型的角膜手术。角膜上密密麻麻地分布着感觉神经，对角膜上皮起营养作用。这些神经的损伤会导致并发症，如角膜知觉减退和干眼，以及伤口愈合降低(2-4)，从而导致透明度和视力的丧失。鉴于这一问题的频率和重要性，本研究项目致力于通过对损伤后脂质细胞信号机制在促进这些手术后受损的角膜神经再生中所起的作用的创新性理解来降低术后并发症的发生率。我们将明确色素上皮衍生因子(PEDF)和二十二碳六酸(DHA)治疗促进角膜神经再生的机制。我们的中心假设是PEDF激活了一个脂质细胞信号机制，刺激12/15脂氧合(12/15-LOX)，增加神经保护素D1(NPD1)和花生四烯酸(AA)衍生信使的合成，参与角膜上皮细胞的神经保护和神经再生，并降低干眼的发生率。我们预测，NPD1调节角膜损伤后的细胞生存信号，是神经再生的主要介导者。我们将使用体内角膜手术动物模型来验证这一假设，该模型包括遗传模型(12/15-LOX基因敲除小鼠)、体内感官测量和共聚焦显微镜、液相色谱-质谱脂组学分析以及细胞和分子方法。我们的具体目标是检验以下假设：(1)角膜手术后PEDF增加，并刺激12/15-LOX的表达，进而合成NPD1和AA衍生介质；(2)12/15-LOX产品选择性地诱导角膜损伤后的神经再生；(3)NPD1作为角膜上皮细胞的神经保护剂，可以更好地促进伤口愈合，降低角膜手术后干眼的发生率。我们的研究针对的是与理解和治疗角膜神经损伤引起的并发症相关的神经再生机制。我们的创新方法确定了神经营养性角膜炎和屈光手术后干眼的潜在治疗药物。公共卫生相关性：该项目提出的研究重点是促进角膜手术后受损的角膜神经的再生，通过对损伤后脂质细胞信号机制所起作用的创新性理解来减少术后并发症的发生率。建议的研究目标是神经再生的机制，与理解和治疗角膜神经损伤引起的并发症有关。我们的新方法将定义神经营养性角膜炎和屈光手术后干眼的潜在治疗剂，为如何修复或预防这些程序造成的损伤提供新的见解。

DESCRIPTION (provided by applicant): Corneal surgery, including refractive surgery, is one of the most frequent procedures used to correct vision (1). It is estimated that more than 17 million people worldwide have had some type of corneal surgery. The cornea is densely innervated with sensory nerves that exert a trophic influence on the corneal epithelium. Damage to these nerves leads to complications such as corneal hypoesthesia and dry eye as well as decreased wound healing (2-4), which results in loss of transparency and vision. Given the frequency and significance of this problem, this research project focuses on decreasing the incidence of postoperative complications by providing innovative understanding of the role lipid cell signaling mechanisms play after injury in enhancing the regeneration of corneal nerves damaged after these procedures. We will define the mechanism by which treatment with pigment epithelial derived factor (PEDF) and docosahexanoic acid (DHA) increase the regeneration of corneal nerves. Our central hypothesis is that PEDF activates a lipid cell signaling mechanism that stimulates 12/15 lipoxygeneases (12/15-LOX), increasing the synthesis of neuroprotectin D1 (NPD1) and arachidonic acid (AA) derived messengers involved in neuroprotection of corneal epithelial cells and nerve regeneration, and decreasing the incidence of dry eye. We predict that NPD1 modulates cell survival signaling after corneal injury and is the main mediator of nerve regeneration. We will test the hypothesis using an in vivo corneal surgery animal model including a genetic model (12/15-LOX knockout mice); in vivo esthesiometry and confocal microscopy; liquid chromatography-mass spectrometry lipidomic analysis; and cellular and molecular approaches. Our specific aims are to test the hypothesis that: (1) PEDF increases after corneal surgery and stimulates the expression of 12/15-LOX, which in turn synthesizes NPD1 and AA derived mediators; (2) 12/15-LOX products selectively induce neurogenesis after corneal injury; (3) NPD1 acts as a neuroprotective agent in corneal epithelial cells, allowing for better wound healing and decreasing the incidence of dry eye after corneal surgery. Our studies target mechanisms of neuroregeneration relevant for the understanding and treatment of complications generated by corneal nerve damage. Our innovative approach defines potential therapeutic agents for neurotrophic keratitis and dry eye after refractive surgery. PUBLIC HEALTH RELEVANCE: The research proposed in this project focuses on enhancing the regeneration of corneal nerves damaged after corneal surgery procedures to decrease the incidence of postoperative complications by providing innovative understanding of the role lipid cell signaling mechanisms play after injury. The proposed studies target mechanisms of neuroregeneration relevant to understanding and treating complications generated by corneal nerve damage. Our novel approach will define potential therapeutic agents for neurotrophic keratitis and dry eye after refractive surgery, yielding new insights into how injuries stemming from these procedures can be repaired or prevented.