Sphingolipid Metabolism in Drosophila Development

果蝇发育中的鞘脂代谢

• 批准号: 8215761
• 负责人: JULIE D SABA
• 金额: $ 33.37万
• 依托单位: CHILDREN'S HOSPITAL & RES CTR AT OAKLAND
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8215761
• 关键词: Actins; Address; Adult; Animal Model; Apoptosis; Atrophic; Autophagocytosis; Bacterial Infections; Biochemical; Biochemistry; Biological; Biological Models; Biology; Cardiomyopathies; Catabolism; Cell Line; Cell Proliferation; Cell Survival; Cell model; Cells; Cellular Stress Response; Cellular biology; Chemicals; Chest; Complex; Defect; Development; Differentiation and Growth; Disease; Drosophila genus; Drosophila melanogaster; Dynamin; Dystroglycan; Endocytosis; Engineering; Enzymes; Eukaryota; Event; Evolution; Extracellular Matrix; Family; Gene Expression; Gene Targeting; Genetic; Goals; Grant; Growth; Growth and Development function; Homeostasis; Hybrids; Inflammation; Inherited; Injury; Insulin Resistance; Investigation; Knockout Mice; Lipids; Lyase; Maintenance; Malignant Neoplasms; Medical; Membrane; Membrane Biology; Membrane Fusion; Membrane Proteins; Metabolic syndrome; Metabolism; Molecular; Molecular Target; Mus; Muscle; Muscle Cells; Muscle Development; Muscle Fibers; Muscular Atrophy; Muscular Dystrophies; Musculoskeletal Diseases; Myoblasts; Myogenin; Myopathy; Myosin Heavy Chains; Natural regeneration; Neurodegenerative Disorders; Organ; PI3K/AKT; Pathology; Pathway interactions; Pattern; Phenocopy; Phenotype; Phosphorylation; Physiological; Play; Process; Production; Protein Biosynthesis; Protein-Lysine 6-Oxidase; Proteins; Proto-Oncogene Proteins c-akt; Research; Rodent Model; Role; SPHK1 enzyme; Sarcolemma; Signal Transduction; Signaling Molecule; Signaling Protein; Skeletal Muscle; Sphinganine-1-phosphate aldolase; Sphingolipids; Sphingosine-1-Phosphate Receptor; Striated Muscles; System; Testing; Time; Tissues; Translations; Vertebral column; Virus Diseases; Wasting Syndrome; Work; age related; base; cancer therapy; embryo tissue; enzyme activity; experience; fly; frailty; gene therapy; human disease; immune function; migration; muscle regeneration; muscular dystrophy mouse model; mutant; novel; pre-clinical; prevent; protein expression; public health relevance; response; satellite cell; sphingosine 1-phosphate; sphingosine kinase; sphingosine-1-phosphate lyase

DESCRIPTION (provided by applicant): Sphingolipids are a conserved family of lipids built upon a sphingoid base backbone. Sphingolipids serve structural membrane functions, whereas their metabolism produces signaling molecules involved in regulating mammalian development, immune function, inflammation and cellular stress responses. Studies supported by this grant have explored the role of sphingolipids in the model organism Drosophila melanogaster. These studies have resulted in the chemical characterization of Drosophila sphingoid bases and the identification of novel endogenous Drosophila sphingolipids with potent growth-inhibitory activity. Further, we have shown that Sply mutants lacking expression of Drosophila sphingosine-1-phosphate (S1P) lyase (SPL), which is responsible for the final step of sphingolipid degradation, accumulate sphingolipid intermediates and develop a progressive myopathy in the thoracic muscles needed to power flight. The Sply myopathy is corrected by reducing sphingolipid production, indicating sphingolipid intermediates play a causative role. We have observed that mutants in key membrane proteins such as dynamin and dystroglycan phenocopy the Sply myopathy. We have also conducted cell-based investigations that suggest that Sply/SPL is required for normal AKT signaling, protein translation, myoblast fusion, myoblast gene expression and control of autophagy. Many of these interactions have been corroborated in murine C2C12 cells, indicating that SPL plays a conserved role in myoblast survival, fusion and differentiation. We have also found that sphingosine kinase and S1P lyase are dynamically upregulated during murine muscle regeneration, leading to a transient peak in S1P levels in regenerating muscle. These collective observations have led us to propose our central hypothesis, which states that SPL plays a critical role in muscle biology, development and homeostasis. The specific aims of our proposal are, thus: 1) To define the role of SPL in muscle cell biology; 2) To dissect the role of SPL in muscle development; and 3) To establish the role of SPL in muscle atrophy and regeneration. Our long-term goals are to exploit Drosophila to elucidate the role of sphingolipids in biology, membrane function, and tissue homeostasis and to define the relevance of these findings to human disease. Due to species-specific structural differences in sphingolipids and the lack of S1P receptors in lower eukaryotes, we do not expect the two systems to be equivalent. Thus, our goals are to compare the biochemical and molecular events associated with SPL loss in Drosophila and murine cell and animal models, with the intent of developing a comprehensive understanding of how SPL functions in the context of muscle tissue and how its function may have been modified throughout evolution. These studies should be readily achieved by our team, which has extensive experience in sphingolipid biochemistry, Drosophila genetics, and the genetics and pathology of MD. PUBLIC HEALTH RELEVANCE: The studies proposed in this application will elucidate mechanisms by which sphingolipids influence key processes involved in muscle development and regeneration, including myogenic gene expression, membrane fusion, satellite cell activation, muscle membrane structure and extracellular matrix processing. Our research plan includes studies to specifically address the translational relevance of S1P metabolism in mammalian muscle injury, atrophy and regeneration using preclinical rodent models. The information gained from this work is therefore relevant to muscle-wasting syndromes, age-related frailty, inherited muscular dystrophies and related musculoskeletal disorders arising from defects of extracellular matrix remodeling. Skeletal muscle is also a prime target organ for gene therapy, since engineered myoblasts can be made to fuse with mature muscle, generating a stable hybrid organ within the adult. Thus, our studies of myoblast fusion may be relevant to an array of disorders potentially treatable by genetic therapy. Our proposed studies will also characterize how sphingolipids interact with the PI3K/AKT pathway, a key membrane-localized signaling hub that regulates cell survival, protein synthesis, and autophagy and gene expression. Our main focus is on how sphingolipids influence this pathway in muscle. However, understanding endogenous regulators of the AKT pathway is relevant to the vastly important medical problem of insulin- resistance and metabolic syndrome, whereas devising new pharmacological agents to inhibit PI3K/AKT signaling is a major objective in the treatment of cancer. Excessive autophagy underlies many human disease states including neurodegenerative diseases, cardiomyopathies, cancer, programmed cell death, and bacterial and viral infections. Thus, our research plan has potentially broad translational significance.

描述（由申请人提供）：鞘脂是建立在鞘脂碱骨架上的保守脂质家族。鞘脂具有结构膜功能，而它们的代谢产生参与调节哺乳动物发育、免疫功能、炎症和细胞应激反应的信号分子。该基金支持的研究探索了鞘脂在模式生物果蝇中的作用。这些研究导致果蝇鞘氨醇碱的化学表征和鉴定新的内源性果蝇鞘脂具有强效的生长抑制活性。此外，我们已经表明，缺乏果蝇鞘氨醇-1-磷酸（S1 P）裂解酶（SPL），这是负责鞘脂降解的最后一步表达的Sply突变体，积累鞘脂中间体，并在动力飞行所需的胸肌中发展为进行性肌病。Sply肌病通过减少鞘脂产生而得到纠正，表明鞘脂中间体起致病作用。我们已经观察到关键膜蛋白如发动蛋白和肌营养不良蛋白聚糖的突变体与Sply肌病表型相似。我们还进行了基于细胞的研究，表明Sply/SPL是正常AKT信号传导、蛋白质翻译、成肌细胞融合、成肌细胞基因表达和自噬控制所必需的。其中许多相互作用已在小鼠C2 C12细胞中得到证实，表明SPL在成肌细胞存活、融合和分化中发挥保守作用。我们还发现鞘氨醇激酶和S1 P裂解酶在小鼠肌肉再生过程中动态上调，导致再生肌肉中S1 P水平的瞬时峰值。这些集体观察使我们提出了我们的中心假设，即SPL在肌肉生物学，发育和稳态中起着关键作用。因此，我们建议的具体目标是：1）定义SPL在肌肉细胞生物学中的作用; 2）剖析SPL在肌肉发育中的作用; 3）建立SPL在肌肉萎缩和再生中的作用。我们的长期目标是利用果蝇阐明鞘脂在生物学、膜功能和组织稳态中的作用，并确定这些发现与人类疾病的相关性。由于鞘脂的物种特异性结构差异和低等真核生物中缺乏S1 P受体，我们不期望这两个系统是等同的。因此，我们的目标是比较果蝇和小鼠细胞和动物模型中SPL损失相关的生化和分子事件，目的是全面了解SPL在肌肉组织中的功能以及其功能在整个进化过程中如何被修改。我们的团队在鞘脂生物化学、果蝇遗传学以及MD的遗传学和病理学方面具有丰富的经验，这些研究应该很容易完成。 公共卫生相关性：本申请中提出的研究将阐明鞘脂影响肌肉发育和再生中涉及的关键过程的机制，包括生肌基因表达、膜融合、卫星细胞活化、肌肉膜结构和细胞外基质加工。我们的研究计划包括使用临床前啮齿动物模型专门研究哺乳动物肌肉损伤，萎缩和再生中S1 P代谢的翻译相关性。因此，从这项工作中获得的信息与肌肉萎缩综合征、年龄相关性虚弱、遗传性肌营养不良症和由细胞外基质重塑缺陷引起的相关肌肉骨骼疾病有关。骨骼肌也是基因治疗的主要靶器官，因为工程化的成肌细胞可以与成熟的肌肉融合，在成人体内产生稳定的杂交器官。因此，我们对成肌细胞融合的研究可能与一系列可能通过遗传疗法治疗的疾病有关。我们提出的研究还将描述鞘脂如何与PI 3 K/AKT通路相互作用，PI 3 K/AKT通路是一个关键的膜定位信号枢纽，调节细胞存活，蛋白质合成，自噬和基因表达。我们主要关注鞘脂如何影响肌肉中的这一途径。然而，理解AKT途径的内源性调节剂与胰岛素抗性和代谢综合征的非常重要的医学问题相关，而设计新的药理学试剂来抑制PI 3 K/AKT信号传导是癌症治疗的主要目标。过度的自噬是许多人类疾病状态的基础，包括神经退行性疾病、心肌病、癌症、程序性细胞死亡以及细菌和病毒感染。因此，我们的研究计划具有潜在的广泛的翻译意义。