DNA Repair Mechanisms and Circadian Clock Disruption in the Cornea

项目摘要 每年约有42,000名美国人需要角膜移植，全世界 可供移植的角膜短缺。角膜是眼睛最外层的透明保护层。它 形成眼睛的第一道屏障，因此它暴露在环境中。角膜保护内部 在进入眼睛的光线到达视网膜之前，它将进入眼睛的光线聚焦到晶状体上。这个 眼睛和皮肤是暴露在太阳下的器官，因此容易受到太阳紫外线的DNA损伤 辐射，眼皮肿瘤占所有皮肤癌的5%-10%。与皮肤不同，健康的角膜缺乏 血管，它是免疫豁免的场所。眼部损伤或感染可导致角膜 如果不治疗可能导致失明的炎症。急性日光照射可引起角膜光性角膜炎 而长期暴露在阳光下会导致角膜晒伤，这可能会因炎症而导致视力丧失 以及疤痕、肿瘤或感染。已知小鼠昼夜节律紊乱会导致慢性角膜 发炎。最近的发现表明，昼夜节律的改变对角膜上皮细胞有影响。 维修和保养。了解环境暴露的后果，如太阳中波紫外线 辐射和环境对生物钟的破坏，如角膜修复过程中的时差条件 将阐明影响角膜DNA修复和炎症的潜在分子机制 在人类身上。在人类和小鼠中，核苷酸切除修复(NER)可以消除UVB造成的遗传损伤。 因此，防止UVB暴露和确保有效的NER能力对于维护 基因组稳定性、组织更新和预防角膜肿瘤。我们的中心假设是 由于昼夜节律的破坏，角膜中的DNA修复受到破坏，从而导致 发炎的过程。我们的研究使用了野生型SKH1无毛小鼠和昼夜节律紊乱的PER1/2基因 SKH1基因缺陷小鼠模型和模拟慢性时差反应的野生型小鼠。在目标1a中，我们将确定 紫外线照射对野生型SKH1无毛小鼠角膜DNA修复和炎症的影响。在……里面 Aim1b，我们将描述昼夜节律紊乱如何调节DNA修复机制和 在母基金中建议的使用SKH1无毛小鼠的小鼠角膜炎症途径。这个 这些研究的结果将提供对DNA修复和炎症过程的机械性洞察 发生在角膜及其对昼夜节律紊乱的依赖性，并最终将导致 改进的眼科治疗。

Project Summary Approximately 42,000 Americans each year are in the need of a corneal transplant, with worldwide shortage of corneas for transplantation. The cornea is the transparent outermost protective layer of the eye. It forms the first barrier of the eye, and as such it is exposed to the environment. The cornea protects the internal structures of the eye and it focuses the light entering the eye on the lens before the light reaches the retina. The eyes and skin are the organs exposed to the sun and are therefore susceptible to DNA damage by solar UVB radiation, with eyelid tumors making up 5-10% of all skin cancers. Unlike the skin, a healthy cornea is devoid of blood vessels and it is a site of immune privilege. Injuries or infections of the eye can result in corneal inflammation that may lead to blindness if left untreated. Acute sun exposure can cause corneal photokeratitis while chronic exposure to the sun causes corneal sunburn, which can lead to vision loss due to inflammation and scarring, neoplasia or infection. Circadian disruption in mice is known to result in chronic corneal inflammation. Recent findings have shown that change in circadian rhythm has implications in corneal epithelial repair and maintenance. Understanding the consequences of environmental exposures such as solar UVB radiation and environmental disruption of the circadian clock such as jetlag conditions on corneal repair process would shed light on the underlying molecular mechanisms that influence corneal DNA repair and inflammation in humans. In humans and mice, nucleotide excision repair (NER) removes genetic damage caused by UVB. Therefore, protection from UVB exposure and ensuring efficient NER capacity are critical for maintenance of genomic stability, tissue renewal and for the prevention of neoplasia of the cornea. Our central hypothesis is that DNA repair in the cornea is undermined by the disruption of circadian rhythm, thus resulting in dysregulation of the inflammatory processes. Our study uses wildtype SKH1 hairless mice and circadian-disrupted Per1/2 genes defective SKH1 genetic mouse model and chronic jetlag simulated wildtype mice. In Aim 1a, we will determine the impact of UVB exposure on DNA repair and inflammation on wildtype SKH1 hairless mouse corneas. In Aim1b, we will characterize how circadian rhythm disruption would regulate DNA repair mechanisms and inflammatory pathways in mouse corneas using SKH1 hairless mice as proposed in the parent grant. The outcomes from these studies would provide mechanistic insight into the DNA repair and inflammatory processes occurring in the cornea and their dependency on circadian rhythm disruptions and will eventually lead to improved ocular therapies.