Klotho regulation and aging

描述（由申请人提供）：我们的研究重点是研究年龄抑制蛋白Klotho是如何随着大脑的衰老而调节的。当Klotho表达被消除时，小鼠发育正常，但在4月龄时衰老至死亡。这种快速恶化伴随着一种与老年人（认知障碍、动脉粥样硬化、异位钙化、肺气肿、骨质疏松、皮肤萎缩和脱发、胸腺退化、不育症和骨密度下降）相似的表型。在小鼠体内消除Klotho会导致与氧化应激增加有关的认知障碍。相比之下，过表达Klotho的转基因小鼠的寿命延长了30%，并具有抗氧化应激能力。我们的研究小组发现，Klotho在衰老的非人灵长类动物、大鼠和小鼠大脑中下调。这些发现使我们假设Klotho在大脑功能中很重要，随着年龄的增长，它的下调可能是氧化应激的结果，如果防止氧化应激，可以改善神经退行性疾病。这项工作提出，研究Klotho启动子和3'UTR随年龄的调节以及氧化损伤对Klotho启动子随年龄的影响。我们将确定Klotho启动子的高GC含量是否使其成为与年龄相关的下调的目标，因为氧化应激会随着时间的推移而累积损伤。这将通过比较Klotho启动子的氧化状态和其他基因的氧化状态来完成，无论是在体外还是在年老恒河猴大脑的死后样本中。我们还将研究结合并诱导Klotho启动子激活的转录因子。Klotho启动子不包含转录起始的经典元件。了解哪些因素对Klotho转录重要，可能有助于揭示导致Klotho激活的信号通路以及Klotho在正常细胞中的作用。最后，我们将确定Klotho是否受microRNAs （miR）的调节，以及miR在大脑中如何随着年龄的增长而变化。MiR结合并调节mRNA的翻译，MiR是否以及如何影响Klotho加工尚不清楚。同样，了解调控Klotho的过程将使我们更好地了解影响Klotho的过程以及Klotho在细胞功能中更广泛的作用。这项工作的结果将增加抗衰老基因Klotho的新知识，并阐明氧化损伤如何选择性下调特定基因的可能机制。

DESCRIPTION (provided by applicant): The focus of our study is to examine how the age suppressor protein, Klotho, is regulated with aging in the brain. When Klotho expression is eliminated, mice develop normally, but age to death by 4 months of age. This rapid deterioration is accompanied with a phenotype not unlike what is observed in aged humans (cognitive impairment, atherosclerosis, ectopic calcification, emphysema, osteoporosis, skin atrophy and hair loss, thymic involution, infertility and decreased bone mineral density). Elimination of Klotho in mice causes cognitive impairment that is associated with increased oxidative stress. In contrast, Klotho overexpressing transgenic mice live longer by up to 30% and are resistant to oxidative stress. Our group found that Klotho is downregulated in the aging non-human primate, rat and mouse brains Together, these have lead us to hypothesize that Klotho is important in brain function and its downregulation with age may be the result of oxidative stress which, if prevented, could ameliorate decline into neurodegenerative disease. The work proposed, examines regulation of the Klotho promoter and 3'UTR with age and the effect of oxidative damage to the Klotho promoter with age. We will determine whether the high GC content of the Klotho promoter makes it a target for age-related downregulation because of damage that accumulates over time because of oxidative stress. This will be done by comparing the oxidation state of the Klotho promoter to that of other genes both in vitro and in post mortem samples from aged rhesus monkey brain. We will also work to characterize the transcription factors that bind and induce activation of the Klotho promoter. The Klotho promoter does not contain the classical elements for transcription initiation. Understanding what factors are important for Klotho transcription may shed light on signaling pathways leading to Klotho activation and the role of Klotho in the normal cell. Last, we will determine whether Klotho is regulated by microRNAs (miR) and how miR change in the brain with age. MiR bind and regulate translation of mRNA and nothing is known about whether and how miR affect Klotho processing. Again, understanding the processes that regulate Klotho will enable us to have a better understanding of the processes that affect Klotho and Klotho's wider role in cellular function. The results of this work will add new knowledge on both the anti-aging gene Klotho and elucidate a possible mechanism for how oxidative damage selectively downregulates specific genes. PUBLIC HEALTH RELEVANCE: With a rapidly aging population, increases in age related disorders are anticipated to rise to unprecedented levels in the next 50 years. Understanding the regulation of genes known to effect and be affected by the aging process is critical to developing novel therapies for a range of disorders. The aging suppressor protein, Klotho is decreased in the brain with age and may be a target for therapeutic development against neurodegenerative disorders.