mTOR-mediated Signaling Pathway in Aging of the Retinal Pigment Epithelium

描述(由申请者提供)：申请者研究计划的长期目标是探索老年性黄斑变性(AMD)病因的分子机制，并开发新的靶向治疗策略。这笔K99/R00赠款将促进申请者过渡到范德比尔特眼科研究所的独立研究员，该研究所拥有丰富的科学合作环境，并培育初级科学家的职业发展。AMD是美国老年人失明的主要原因。大多数AMD患者患有萎缩性(干性)型疾病，目前只有有限的治疗选择。萎缩性AMD可能是由于基因/环境相互作用导致视网膜色素上皮(RPE)进行性退化所致。老龄化是AMD最明确的环境风险因素。我们推测，哺乳动物靶标雷帕霉素(MTOR)介导的信号通路在控制RPE衰老过程中发挥关键作用。最近的文献数据表明，mTOR在整合各种环境信号并将它们与改变的组织功能和生物体的寿命联系起来方面发挥着关键作用，这一假说得到了支持。在我们的初步研究中，我们发现雷帕霉素在体外逆转了原代人RPE细胞的衰老表型。为了进一步检验我们的假设，我们在这一应用中提出了三个具体目标。目的1是确定衰老过程如何调节RPE中的mTOR通路。目的2是通过调节自噬的潜在机制来确定调节mTOR信号如何影响RPE的体外老化。目的3是利用在视网膜形成AMD样表型的SOD1基因敲除小鼠，确定mTOR是否在体内调节RPE的老化。在指导阶段，申请人将在指导委员会的监督下进行拟议的实验，指导委员会由具有AMD病因和发病机制(Paul Sternberg博士)、视网膜神经变性动物模型(David Calkins博士)和mTOR/自噬(Lu Bo博士)专业知识的导师组成。委员会成员将定期开会，监督研究进展，并帮助申请者推动其职业生涯走向独立。R00阶段的研究将在与AMD相关的动物模型中测试mTOR抑制剂的潜在治疗效果。这些研究的结果将为RPE和视网膜的老化和与年龄相关的退化提供新的机制信息。 与公共健康相关：该项目致力于描述一种新的信号转导途径，它可能控制视网膜的衰老过程，并有助于老年性黄斑变性(AMD)。这些研究的结果可能会转化为治疗萎缩型AMD的新方法。

DESCRIPTION (provided by applicant): The long term goal of the Applicant's research program is to explore the molecular mechanisms underlying the etiology of age-related macular degeneration (AMD) and develop novel target-based therapeutic strategies. This K99/R00 grant will facilitate the transition for the Applicant to become an independent investigator at the Vanderbilt Eye Institute, which has a rich environment of scientific collaboration and nurturing career development of junior scientists. AMD is the leading cause of blindness in elderly Americans. The majority of AMD patients has atrophic (dry) form of the disease and has only limited treatment options at the present time. Atrophic AMD is likely resulted from gene/environmental interaction causing progressive degeneration of the retinal pigment epithelium (RPE). Aging is the most well defined environmental risk factor of AMD. We hypothesize that the mammalian target of rapamycin (mTOR)-mediated signaling pathway plays key roles in controlling the aging process of the RPE. The hypothesis is supported by recent literature data suggesting that mTOR plays key roles in integrating various environmental signals and linking them to altered tissue function and organism's life span. In our preliminary studies, we found that rapamycin reversed the senescent phenotype of primary human RPE cells in vitro. To further test our hypothesis, we have proposed three specific aims in this application. Aim 1 is to determine how the aging process regulates mTOR pathways in the RPE. Aim 2 is to determine how modulating the mTOR signaling affects RPE aging in vitro by a potential mechanism of regulating autophagy. Aim 3 is to determine whether mTOR regulates aging of the RPE in vivo using SOD1 knockout mice which develop AMD-like phenotype in the retina. During the mentored phase, the Applicant will conduct the proposed experiments under the supervision of a mentoring committee, which is consisted of mentors with expertise in AMD etiology and pathogenesis (Dr. Paul Sternberg), animal models of neurodegeneration in the retina (Dr. David Calkins) and mTOR/autophagy (Dr. Lu Bo). Members of the committee will meet regularly, monitor the research progress and assist the Applicant to advance her career towards independence. Research at the R00 phase will test the potential therapeutic effects of mTOR inhibitors in an animal model relevant to AMD. Results from these studies will provide novel mechanistic information on aging and age-related degeneration of the RPE and retina. PUBLIC HEALTH RELEVANCE: This project focuses on characterizing a novel signal transduction pathway which may control the aging process of the retina and contribute to age-related macular degeneration (AMD). Results from the studies can potentially be translated into new therapeutic approaches for treating the atrophic form of AMD.