Role of Anti-aging Klotho Gene on Adaptation to Oxidative Stress

描述(申请人提供)：Klotho最初被鉴定为抗衰老基因，但Klotho蛋白具有包括抗氧化在内的多种作用。低氧导致线粒体活性氧自由基(ROS)泄漏，可作为肺泡生长、重塑和细胞寿命的生理信号。相反，高氧会产生过量的ROS，导致肺泡退化，类似于肺气肿。因此，低氧和高氧都会对肺造成氧化应激。有趣的是，Klotho缺乏症会导致寿命短、生长迟缓、动脉粥样硬化、器官退化和肺气肿的过早衰老综合征。Klotho缺失(KL-/-)纯合子小鼠在年轻时死亡，并出现广泛的异常。杂合子小鼠(KL)患上肺气肿，但其他方面都是正常的。目前尚不清楚产生过量Klotho蛋白(TG-KL)的转基因小鼠是否受到氧化损伤的保护。我们假设，肺的生长和衰老代表了由一组共同的基因调节的氧化应激适应光谱中的不同终点，Klotho处于这些途径的中心阶段。目的是探讨Klotho对出生后暴露于不同氧气压力下的动物的肺生长和功能的影响。我将确定氧化应激对Klotho基因缺乏或过表达小鼠肺结构和功能的影响，并验证Klotho缺乏损害低氧诱导的肺生长并加速高氧诱导的肺损伤，而Klotho过表达促进低氧诱导的肺生长并减轻高氧诱导的肺损伤的假说。转基因小鼠和相匹配的对照组将暴露在13、21或40%的氧气中3wk，随后测量肺功能、超微结构和氧化损伤的生物标志物。最后，我将在体外测试Klotho对肺上皮细胞对氧化损伤反应能力的直接影响。这些研究扩大了我的训练范围和科学探索。Kuro-o博士和Moe博士一直在研究Klotho对衰老和疾病在多个器官中的相互作用的代谢影响。他们开始对肺感兴趣，因为它是KL小鼠中唯一表现出基线异常的器官。我将在莫博士的实验室里负责Klotho工作组的肺部部分。我将把我作为一名生物工程师在博士培训中学到的东西应用到这个新模型中。我将在一个新的环境中，除了生理学之外，我还将更加重视细胞和分子生物学。这些结果将促进我们对肺生长和衰老之间联系的基本机制的理解，为操纵Klotho生产是促进肺生长还是防止退化提供新的见解，并为探索Klotho蛋白的潜在用途奠定基础，可能通过吸入传递来促进肺生长或减轻慢性肺部疾病治疗中的破坏。由于Klotho缺乏症也存在于人类中，Klotho疗法正在被深入研究，这个课题具有广泛的生物学和临床意义，将是我开始生物医学研究生涯的理想平台。 与公共健康相关：Klotho是一种抗衰老蛋白质，具有多种作用，包括抗氧化作用。我的目标是了解Klotho如何调节暴露在不同氧气水平下的肺结构和功能的适应。研究将使用不产生Klotho的转基因小鼠来研究Klotho缺乏的肺是否更容易受到氧化损伤，产生过量Klotho的转基因小鼠的肺是否受到氧化损伤的保护，以及Klotho是否在细胞培养模型中直接调节肺细胞抵抗氧化损伤的能力。这些研究将建立在我博士培训的优势之上，并扩展我的技术和智力技能。这些结果有助于我们了解调节肺生长和衰老的机制，并探索Klotho在保护或治疗慢性肺部疾病方面的潜在用途。由于Klotho缺乏症存在于人类，这一主题具有直接和广泛的生物学和临床意义。

DESCRIPTION (provided by applicant): Klotho was first identified as an anti-aging gene but Klotho protein has multiple effects including anti-oxidation. Hypoxia induces mitochondrial leak of reactive O2 species (ROS), which can serve as physiologic signals for alveolar growth and remodeling and cell longevity. Conversely, hyperoxia produces excess ROS that induce alveolar degeneration resembling emphysema. Hence, both hypoxia and hyperoxia impose oxidative stress on the lung. Interestingly Klotho deficiency causes a premature aging syndrome with short lifespan, growth retardation, atherosclerosis, organ degeneration and pulmonary emphysema. Mice homozygous for Klotho deletion (KL-/-) die at a young age with widespread abnormalities. Heterozygous mice (KL) develop pulmonary emphysema but are otherwise normal. It is not known if transgenic mice producing excess Klotho protein (Tg-KL) are protected from oxidative damage. We postulate that growth and aging of the lung represent different ends in the spectrum of adaptation to oxidative stress regulated by a shared set of genes, and that Klotho is at the center stage of these pathways. The Aim is to explore the role of Klotho on lung growth and function in animals exposed to different O2 tensions during postnatal life. I will determine the effects of oxidative stress on lung structure and function in mice bearing deficiency or overexpression of the Klotho gene, and test the hypothesis that Klotho deficiency impairs hypoxia-induced lung growth and accelerates hyperoxia- induced lung damage while Klotho overexpression augments hypoxia-induced lung growth and mitigates hyperoxia-induced lung damage. Genetically modified mice and matched controls will be exposed to 13, 21 or 40% O2 for 3 wk, followed by measurement of lung function, ultrastructure, and biomarkers of oxidative damage. Finally, I will test the direct effects of Klotho on the ability of lung epithelial cells to react to oxidative insult in vitro. These studies expand the scope of my training as well as the scientific quest. Drs. Kuro-o and Moe have been investigating the metabolic effects of Klotho on the interaction of aging and disease in multiple organs. They became interested in the lung since it is the only organ in the KL mice that exhibits baseline abnormalities. I will take on the pulmonary part of this Klotho working group in Dr. Moe's laboratory. I will apply what I have learned in my doctorate training as a bioengineer to this new model. I will be in a new environment with greater emphasis on cell and molecular biology in addition to physiology. The results will advance our understanding of fundamental mechanisms that link lung growth and aging, offer new insight into whether manipulation of Klotho production enhances lung growth or protects against degeneration, and lay the foundation for exploring potential uses of Klotho protein, perhaps by inhalational delivery, to augment lung growth or mitigate destruction in the treatment of chronic lung disease. Since Klotho deficiency also exists in humans and Klotho therapy is being intensely studied, this topic has broad biologic and clinical relevance and will be an ideal platform to launch my career as a biomedical researcher. PUBLIC HEALTH RELEVANCE: Klotho is an anti-aging protein with multiple effects including anti-oxidative actions. My goal is to understand how Klotho modulates the adaptation in lung structure and function induced by exposure to different oxygen levels. Studies will examine whether Klotho-deficient lungs are more susceptible to oxidative damage using transgenic mice that do not produce Klotho, whether the lungs from transgenic mice producing excess Klotho are protected from oxidative damage, and whether Klotho directly modulates the ability of lung cells to resist oxidative damage in a cell culture model. The studies will build on the strengths of my doctoral training and expand my technical and intellectual skills. The results help us understand the mechanisms that regulate lung growth and aging, and explore a potential use of Klotho in the protection or treatment of chronic lung diseases. Since Klotho deficiency exists in humans, this topic has immediate and broad biologic and clinical relevance.