Fundamental Studies on the Regulation and Interaction of Ceramides in Cellular Senescence and Cell Death

哺乳动物细胞产生多种具有不同功能的脂质。作为生物膜的主要成分，脂质形成屏障，定义细胞及其内部隔室的边界。脂质还在细胞分裂和程序性死亡等重要细胞过程中发挥着重要作用。这些功能可以依赖于单个脂质类型的细胞定位和与它们相互作用的其他生物分子，以及它们的细胞位置。在此背景下，该项目将应用生化、化学生物学和分析方法来研究特定脂质组（神经酰胺）在细胞衰老中的作用，细胞衰老是一个由细胞分裂停止定义的过程。这些结果有望揭示细胞衰老中调节脂质功能的新的基本生化机制，并对更广泛地理解神经酰胺在生物过程中的作用具有重要意义。结果也应该推广到其他细胞类型。此外，该项目将在教育领域培养具有全球竞争力的劳动力，包括STEM领域代表性不足群体的学生和教师参与研究和科学探究。已有研究表明神经酰胺参与细胞凋亡和复制性衰老。复制性衰老是细胞达到其增殖能力时发生的细胞周期停滞状态。它是与机体老化和伤口愈合相关的基本细胞过程，不同于细胞凋亡。神经酰胺的促凋亡活性已被充分研究；然而，神经酰胺如何在复制性衰老中起作用仍然未知。本研究的目的是阐明神经酰胺在复制性衰老中产生、细胞定位和功能的生化机制。为了实现这一目标，将鉴定与神经酰胺相互作用的蛋白质，研究这些相互作用的功能后果，并确定衰老过程中调节神经酰胺水平的生化机制。该项目将使用比较衰老细胞系模型的实验设计来研究神经酰胺参与复制性衰老的具体机制。此外，该研究首次整合了多种成像、脂质组学和基于微动的方法，全面解决了衰老过程中细胞器水平神经酰胺的调控、运输和蛋白质相互作用。从这个项目中获得的知识将为研究细胞位置对细胞中脂质种类功能的影响的新研究打开大门。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Mammalian cells produce many types of lipids with different functions. As major components of biological membranes, lipids form barriers that define boundaries for cells and their internal compartments. Lipids also participate in distinct roles that signal essential cellular processes, such as cell division and programmed cell death. These functions can depend on the cellular localization of individual lipid types and other biological molecules with which they interact, as well as their cellular locale. Within this context, this project will apply biochemical, chemical biological, and analytical approaches to investigate the role of a specific lipid group (ceramides) in cellular senescence, a process that is defined by the cessation of cell division. The outcomes are expected to reveal novel fundamental biochemical mechanisms that regulate lipid function in cellular senescence and to have important implications for broader understanding of the role of ceramides in biological processes. The results should also be generalizable to other cell types. In addition, the project will provide for training of a globally competitive workforce across the educational spectrum, including participation of students from groups underrepresented in STEM and teachers in research and scientific inquiry.Previous studies showed that ceramides are involved in apoptosis and replicative senescence. Replicative senescence is a state of cell cycle arrest that occurs when cells reach their proliferative capacity. It is a fundamental cellular process linked to organismal aging and wound healing, distinct from apoptosis. The pro-apoptotic activity of ceramides is well-studied; however, how ceramides function in replicative senescence remains unknown. The goal of this proposal is to elucidate the biochemical mechanisms that regulate the production, cellular localization, and function of ceramides in replicative senescence. To achieve this goal, proteins that interact with ceramides will be identified, the functional consequences of these interactions will be investigated, and biochemical mechanisms that regulate ceramide levels in senescence will be determined. The project will use an experimental design comparing senescent cell line models to investigate specific mechanisms by which ceramides are involved in replicative senescence. Further, for the first time, the study integrates multiple imaging, lipidomics, and perturbation-based methods to comprehensively resolve the regulation, trafficking, and protein interactions of ceramides at the organelle level during senescence. The knowledge obtained from this project will open the door to novel studies investigating the impact of cellular locale on the function of lipid species in cells.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.