Defining the Impact of Lipid Synthesis and Turnover on Aging in C. elegans

项目摘要/摘要 细胞膜不是简单的屏障，适当的膜成分对于 确保膜的正常功能。事实上，由于膜成分改变而导致的功能障碍 已在多种疾病中观察到，包括癌症、神经退行性疾病和与年龄有关的疾病 疾病。已知膜的组成影响其关键性能，包括渗透性， 曲率和流动性；然而，影响这些成分的脂肪加工途径和调节器 变化尚未确定。这在很大程度上是因为在体内研究膜 动力学一直受到限制，因为它们需要高水平的同位素浓缩才能获得分辨率 需要对膜脂进行详细分析。在范吉尔斯特实验室，我开发了稳定的同位素浓缩 线虫中的策略，允许将饮食中的碳量化为动物的脂肪酸。 这些同位素加料策略提供了磷脂通量分析所需的浓缩水平 膜动力学。在这项建议中，我将把这些稳定同位素示踪方法的范围扩大到 用气体法测定膜中酰链和磷脂头基团的转化率和合成 色质联用(GC/MS)和液质联用(LC/MS)， 分别进行了分析。在这样做的过程中，我希望定义许多影响膜成分及其 应对压力的能力，并最终有助于全面了解膜生物学和 动力学。 膜成分最显著的影响之一是老化，磷脂开始 含有更多的饱和脂肪酸，最终使膜更加坚硬和 对它们的功能产生负面影响。例如，老化膜中增加的饱和指数可以 影响扩散特性、转运蛋白功能、囊泡融合，甚至信号传导。进步者 随着年龄的增长，饱和脂肪在细胞膜中的积累被认为是导致 衰老和衰老相关的功能障碍。线虫的遗传工具将使我们能够确定亲缘关系 膜周转率对幼年和老年动物整体膜组成的贡献。目标是 这项建议的目的是定义影响膜老化的遗传调节器和途径，并在 因此，有助于理解膜生物学如何影响衰老过程。

PROJECT SUMMARY/ABSTRACT Cellular membranes are not simple barriers, and the appropriate membrane composition is essential to ensure proper function of the membrane. In fact, dysfunction as a result of altered membrane composition has been observed in a wide range of diseases including cancers, neurodegenerative and age-related diseases. The composition of the membrane is known to impact its key properties including permeability, curvature, and fluidity; however, the lipid processing pathways and regulators that affect these composition changes have not yet been identified. This is largely due to the fact that in vivo studies of membrane dynamics have been limited, because they require high levels of isotope enrichment to obtain the resolution required to analyze membrane lipids in detail. In the Van Gilst lab, I developed stable isotope enrichment strategies in C. elegans that allow for the quantification of dietary carbon into the fatty acids of the animal. These isotope feeding strategies provide the enrichment levels required for flux analysis of phospholipid membrane dynamics. In this proposal, I will expand the scope of these stable isotope tracer methods to assay the turnover and synthesis of the acyl chains and phospholipid head groups in membranes via gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectometry (LC/MS), respectively. In doing so, I hope to define many of the pathways that impact membrane composition and its ability to respond to stress and ultimately contribute to the overall understanding of membrane biology and dynamics. One of the most dramatic impacts of membrane composition is in aging, where the phospholipids begin to contain drastically more saturated fatty acids, ultimately making the membranes much more rigid and negatively impacting their function. As examples, the increased saturation index in the aged membrane can affect diffusion properties, transporter function, vesicle fusion, and even signaling. The progressive accumulation of saturated fat in the membranes over aging has been theorized as a major contributor to aging and aging-related dysfunction. The genetic tools of C. elegans will allow us to determine the relative contribution of membrane turnover on the overall membrane composition in young and old animals. The goal of this proposal is to define the genetic regulators and pathways that influence membrane aging and, in doing so, contribute to the understanding of how membrane biology impacts the aging process.