Highly Conserved 4E-BP Dependent Secreted Proteins from Human and Fly Skeletal Mu

描述(申请人提供)：老龄化本身是许多慢性疾病的头号风险因素，包括心血管疾病、2型糖尿病和神经退行性疾病。衰老的一个生理特征是骨质疏松症，即骨骼肌块逐渐减少，从而失去功能。虽然衰老和肌肉质量下降之间的联系存在于许多物种中，但肌肉质量下降或防止肌肉功能下降的机制尚未完全阐明。同样，许多过程或环境调节剂，如饮食限制(DR)，可以防止衰老过程，从酵母到无脊椎动物模型到脊椎动物模型都是保守的，这表明了共同的分子、生化和生理机制。因此，模式生物，如黑腹果蝇，具有复杂的身体规划，相对较短的寿命，强大的遗传工具，以及明确的衰老表型，是适合 衰老新机制的发现。一种明确的衰老途径是雷帕霉素(TOR)途径的靶点，对TOR途径的调节已被证明可以延长酵母、蠕虫、苍蝇甚至小鼠的寿命。我们和其他人最近发现，TOR下游靶点真核细胞翻译起始因子4E结合蛋白(4E-BP)的肌肉特异性调节具有非自主效应，可以改变脂肪体中的寿命和甘油三酯代谢。一种潜在的机制是通过肌肉分泌具有旁分泌和内分泌作用的蛋白质的能力。我们假设DR/4E-BP在一定程度上通过骨骼肌分泌的蛋白(肌动蛋白)调节其对健康的益处，这种蛋白质具有组织特异性和整个机体的益处。我们还假设4E-BP对肌肉的影响在无脊椎动物和哺乳动物之间是保守的。为了寻找在肌肉中分泌的4E-BP的保守靶点，我们建议利用人的肌肉细胞来确定骨骼肌中依赖4E-BP的分泌蛋白。候选蛋白质的清单将与现有的关于苍蝇胸肌翻译的4E-BP依赖的mRNAs差异的数据进行比较。人和蝇结合的方法将导致高度保守的4E-BP依赖的分泌蛋白的鉴定。一旦鉴定出这些蛋白质，它们将在苍蝇骨骼肌中进行系统的基因操作，以确定它们是否足以和/或必要地促进DR/4E-BP对健康的益处。此外，我们还将检查肌肉中靶标的操纵是否足以改变脂肪体的表型，以及阻断靶标可能的作用机制是否充分或必要 DR/4E-BP对健康范围有好处。总之，我们相信这是一种创新的翻译方法，应该能够洞察高度保守的生物机制，这些机制在衰老和与年龄相关的慢性疾病中很重要。此外，已确定的特定蛋白质可能具有预防/治疗一些与年龄相关的疾病的治疗潜力。

DESCRIPTION (provided by applicant): Aging itself is the number one risk factor for a number of chronic diseases, including cardiovascular disease, type 2 diabetes, and neurodegenerative diseases. One physiological hallmark of aging is sarcopenia or the gradual loss of skeletal muscle mass and therefore functions. While the link between aging and muscle mass loss exists across many species, the mechanism by which muscle mass loss or prevention of declining muscle function have not been completely elucidated. Similarly, many of the processes or environmental modifiers, such as dietary restriction (DR), which can protect against the aging process, are conserved from yeast to invertebrate model to vertebrate models, suggesting common molecular, biochemical, and physiological mechanisms. Thus, model organisms, such as the Drosophila Melanogaster, with complex body plans, relatively short life span, powerful genetic tools, and well defined aging phenotypes are ideally situated for the discovery of new mechanisms of aging. One well defined aging pathway is the target of rapamycin (TOR) pathway, modulation of which has been shown to extend lifespan in yeast, worms, flies and even mice. We and others have recently found that muscle specific modulation of eukaryotic translation initiation factor 4E binding protein (4E-BP), a downstream target of TOR has non-autonomous effects that can alter lifespan and triglyceride metabolism in the fat body. One potential mechanism is through the ability of muscle to secrete proteins with paracrine and endocrine actions. We hypothesize that DR/4E-BP mediate their benefits on healthspan in part through skeletal muscle secreted proteins (myokines) that have tissue specific and whole organism benefits. We also hypothesize that effects of 4E-BP on muscle are conserved between invertebrates and mammals. In order to find conserved targets of 4E-BP that are secreted in the muscle, we propose to use human muscle cells to determine the 4E-BP dependent secreted proteins from skeletal muscle. The list of candidate proteins will be compared with existing data on the 4E-BP dependent differences in translated mRNAs from fly thorax muscle. The combination of human and fly approach should lead to identification of high conserved 4E-BP dependent secreted proteins. Once these proteins have been identified they will be systemically genetically manipulated in fly skeletal muscle to determine whether they are sufficient and/or necessary for the DR/4E-BP benefits on healthspan. In additional we will examine whether manipulation of the targets in muscle is sufficient to alter fat body phenotype and whether blocking of the likely mechanism of action of the target is sufficient or necessary for the DR/4E-BP benefits on healthspan. Together we believe this is an innovative translational approach that should provide insight into highly conserved biological mechanisms important in aging and age-related chronic diseases. Furthermore, specific proteins identified may have therapeutic potential to prevent/treat a number of age related diseases.