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

描述（由申请人提供）：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至关重要。事实上，在包括癌症、神经退行性疾病和与年龄相关的疾病在内的广泛疾病中已经观察到由于膜组成改变而导致的功能障碍。已知膜的组成会影响其关键特性，包括渗透性、曲率和流动性;然而，尚未确定影响这些组成变化的脂质加工途径和调节剂。这在很大程度上是由于膜动力学的体内研究受到限制，因为它们需要高水平的同位素富集以获得详细分析膜脂质所需的分辨率。在货车实验室，我开发了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。这些同位素进料策略提供了磷脂膜动力学通量分析所需的富集水平。在本提案中，我将扩大这些稳定同位素示踪方法的范围，分别通过气相色谱/质谱（GC/MS）和液相色谱/质谱（LC/MS）分析膜中酰基链和磷脂头基的周转和合成。在这样做的过程中，我希望定义许多影响膜组成及其对压力反应能力的途径，并最终有助于对膜生物学和动力学的全面理解。膜组成的最显著影响之一是在老化中，其中磷脂开始含有急剧增加的饱和脂肪酸，最终使膜更加坚硬并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。随着年龄的增长，膜中饱和脂肪的进行性积累已经被理论认为是衰老和衰老相关功能障碍的主要原因。C. elegans将使我们能够确定膜更新对年轻和老年动物整体膜组成的相对贡献。该提案的目标是定义影响膜衰老的遗传调节因子和途径，并在此过程中有助于了解膜生物学如何影响衰老过程。 公共卫生相关性：膜的磷脂组成对膜正常发挥功能的能力具有显著影响，并且改变的膜组成与包括癌症、神经退行性疾病和年龄相关疾病在内的多种疾病相关。然而，负责膜组成的异常变化的机制尚未确定。在这里，我将进行一个在体研究膜动力学和维护在C。elegans来定义调节膜组成的途径以及这些途径在衰老过程中如何改变。

DESCRIPTION (provided by applicant): 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. PUBLIC HEALTH RELEVANCE: The phospholipid composition of the membrane has a dramatic impact on the membrane's ability to function properly, and altered membrane composition has been associated with a wide array of diseases including cancers, neurodegenerative and age-related diseases. However, the mechanisms that are responsible for the aberrant changes in membrane composition have not yet been identified. Here, I will perform an in vivo study of membrane dynamics and maintenance in C. elegans to define the pathways that regulate membrane composition and how those pathways are altered during aging.