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， 移植用角膜短缺。角膜是眼睛最外层的透明保护层。它 形成眼睛的第一屏障，因此它暴露于环境中。角膜保护内部 在进入眼睛的光线到达视网膜之前，它将光线聚焦在透镜上。的 眼睛和皮肤是暴露在阳光下的器官，因此容易受到太阳UVB的DNA损伤 眼睑肿瘤占所有皮肤癌的5 - 10%。与皮肤不同，健康的角膜缺乏 它是一个免疫豁免的场所。眼睛的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，这可能会导致视力下降，由于炎症 和疤痕、瘤形成或感染。已知小鼠的昼夜节律紊乱会导致慢性角膜炎。 炎症最近的研究结果表明，昼夜节律的变化对角膜上皮有影响 维修和保养。了解太阳UVB等环境暴露的后果 辐射和环境对生物钟的干扰，如时差对角膜修复过程的影响 将揭示影响角膜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引起的遗传损伤。 因此，保护免受UVB照射和确保有效的NER容量对于维持 基因组稳定性、组织更新和预防角膜瘤形成。我们的核心假设是， 角膜中的DNA修复被昼夜节律的破坏破坏，从而导致角膜中的DNA修复的失调。 炎症过程。我们的研究使用野生型SKH1无毛小鼠和昼夜节律破坏的Per1/2基因 SKH 1缺陷型遗传小鼠模型和慢性时差模拟野生型小鼠。在目标1a中，我们将确定 UVB暴露对野生型SKH1无毛小鼠角膜的DNA修复和炎症的影响。在 目的1b，我们将描述昼夜节律破坏如何调节DNA修复机制， 在小鼠角膜中使用SKH 1无毛小鼠的炎症途径，如在母基金中提出的。的 这些研究的结果将提供对DNA修复和炎症过程的机制性见解， 发生在角膜和他们的依赖昼夜节律中断，并最终导致 改善眼部治疗。

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.