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

项目总结/摘要 细胞膜不是简单的屏障，适当的膜组成对于 确保膜的正常功能。事实上，由于细胞膜成分的改变而导致的功能障碍 已经在广泛的疾病中观察到，包括癌症、神经退行性疾病和与年龄相关的疾病。 疾病已知膜的组成影响其关键性质，包括渗透性， 曲率和流动性;然而，影响这些组成的脂质加工途径和调节剂 尚未确定变化。这在很大程度上是由于膜的体内研究 动力学是有限的，因为它们需要高水平的同位素浓缩来获得分辨率 需要详细分析膜脂。在货车葛兰实验室，我开发了稳定同位素浓缩技术 战略在C。这是一种能够将食物中的碳定量转化为动物脂肪酸的方法。 这些同位素补料策略提供了磷脂通量分析所需的富集水平 膜动力学在本提案中，我将扩大这些稳定同位素示踪方法的范围， 通过气体分析膜中酰基链和磷脂头基的周转和合成 色谱/质谱（GC/MS）和液相色谱/质谱（LC/MS）， 分别在这样做的过程中，我希望能够确定许多影响膜组成及其 应对压力的能力，并最终有助于对膜生物学的全面了解， 动力学 膜组成最显著的影响之一是在老化中，其中磷脂开始 含有更多的饱和脂肪酸，最终使膜更加坚硬， 对其功能产生负面影响。例如，老化膜中增加的饱和指数可以 影响扩散性质、转运蛋白功能、囊泡融合，甚至信号传导。逐步 随着年龄的增长，饱和脂肪在膜中的积累已经被理论认为是 衰老和与衰老相关的功能障碍。C. elegans将允许我们确定相对 在年轻和年老的动物中，膜更新对整体膜组成的贡献。目标 这项建议的一个重要目的是确定影响膜衰老的遗传调节因子和途径， 因此，有助于了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.