Determining the Roles of Sphingolipids in Phagocytosis

确定鞘脂在吞噬作用中的作用

• 批准号: 10301556
• 负责人: Fikadu G. Tafesse
• 金额: $ 25.12万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-16 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10301556
• 关键词: Actins; Anabolism; Apoptotic; Autoimmune Diseases; Biological; Biological Process; Biophysics; Biosensor; CRISPR/Cas technology; Candida albicans; Catabolism; Cell Line; Cell membrane; Cell physiology; Cell surface; Cells; Cellular biology; Ceramide glucosyltransferase; Ceramides; Complex; Cytosol; Data; Defect; Degradation Pathway; Dendritic Cells; Disease; Enzymes; Event; Glucosylceramides; Glycosphingolipids; Goals; Homeostasis; Immunoglobulin G; Impairment; Infection; Ingestion; Innate Immune Response; Innate Immune System; Invaded; Knowledge; Lipids; Mammalian Cell; Mediating; Membrane; Metabolic; Microbe; Modification; Molecular; Mus; Mycobacterium tuberculosis; Natural Immunity; Particulate; Pathology; Pathway interactions; Phagocytes; Phagocytosis; Phagosomes; Phenotype; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Play; Predisposition; Process; Production; Proteins; Reporting; Research; Role; Salmonella; Signal Transduction; Solid; Specificity; Sphingolipids; Sphingomyelins; Sphingosine; Structure; Synapses; System; Therapeutic; Time; Tissues; Vertebral column; Work; Zymosan; analog; base; cell type; chemical genetics; depolymerization; frontier; genetic approach; in vivo; inhibitor/antagonist; innate immune function; insight; macrophage; microbial; novel; particle; pathogen; physical property; polymerization; receptor; receptor mediated endocytosis; recruit; spatiotemporal; sphingomyelin synthase; tool; uptake

PROJECT SUMMARY Phagocytosis is a conserved cellular process that is essential for innate immune responses, tissue homeostasis and is associated with various pathologies, including microbial susceptibility and autoimmune disorders. Although phagocytosis was first described more than a century ago, most of the molecular mechanisms that govern the different stages of phagocytosis, especially the lipid-protein interaction events, are poorly understood. Studies have shown that phagocytosis involves complex membrane reorganization that requires extensive remodeling of lipids at the cell surface. However, the roles of lipids, such as sphingolipids (SPLs) in phagocytosis, remain mostly unknown. We hypothesize that both structural and bioactive SPLs are critical determinant factors in phagocytosis where they are involved in signaling at the phagocytic synapse and/or help form the biophysical structure of the phagosome through recruiting proteins to the newly formed phagosomes. We recently found that the biosynthesis of sphingomyelin (SM), one of the major SPLs in mammalian cells, is critical for phagocytosis. Whether SM itself or its biosynthetic byproducts are essential for this process is unknown. In this application, we plan to characterize the exact lipid species required for phagocytosis. To this end, we will take chemical and genetic approaches to disrupt SM catabolism at multiple points along its degradative pathway in order to examine the roles of distinct SM-derived lipid species during phagocytosis. To gain insight into the mechanism by which these lipids play roles in this process, we also plan to determine the localization, metabolic conversions, and interacting partners of SPLs during phagocytosis. For this, we will employ the recently reported genetically encoded SM biosensor as well as our novel multi- functional SPL precursor analogs. These tools will allow us to examine the subcellular localization of SPLs in a time- and space-dependent manner. Our functional probes will enable us to identify SPL interacting proteins during the different stages of phagocytosis. An understanding of how these class of lipids enables phagocytosis will reveal insights into this fundamental cellular process and help develop therapeutic strategies to pathologies related to phagocytic disorders. 8

项目概要 吞噬作用是一种保守的细胞过程，对于先天免疫反应、组织 体内平衡并与各种病理相关，包括微生物敏感性和自身免疫 失调。尽管吞噬作用在一个多世纪前首次被描述，但大多数分子 控制吞噬作用不同阶段的机制，特别是脂质-蛋白质相互作用事件，是 不太了解。研究表明，吞噬作用涉及复杂的膜重组， 需要对细胞表面的脂质进行广泛的重塑。然而，脂质（例如鞘脂）的作用 （SPL）在吞噬作用中的作用，仍然大多未知。我们假设结构 SPL 和生物活性 SPL 都是 吞噬作用的关键决定因素，它们参与吞噬突触的信号传导 和/或通过将蛋白质招募到新形成的吞噬体中来帮助形成吞噬体的生物物理结构 吞噬体。我们最近发现鞘磷脂（SM）的生物合成，鞘磷脂是生物体内主要的 SPL 之一。 哺乳动物细胞，对于吞噬作用至关重要。 SM 本身或其生物合成副产物对于 这个过程是未知的。在此应用中，我们计划表征所需的确切脂质种类 吞噬作用。为此，我们将采取化学和遗传方法来多方面破坏 SM 分解代谢。 沿着其降解途径的点，以检查不同 SM 衍生脂质种类在过程中的作用 吞噬作用。为了深入了解这些脂质在此过程中发挥作用的机制，我们还计划 确定吞噬过程中 SPL 的定位、代谢转化和相互作用伙伴。为了 为此，我们将采用最近报道的基因编码 SM 生物传感器以及我们的新型多 功能性 SPL 前体类似物。这些工具将使我们能够检查 SPL 的亚细胞定位 时间和空间相关的方式。我们的功能探针将使我们能够识别 SPL 相互作用蛋白 在吞噬作用的不同阶段。了解此类脂质如何实现 吞噬作用将揭示这一基本细胞过程的见解并有助于制定治疗策略 与吞噬细胞疾病相关的病理。 8