Sphingolipid Biology And Disease

鞘脂生物学与疾病

• 批准号: 7153394
• 负责人: RICHARD L. PROIA
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7153394
• 关键词: Gaucher' s disease; Niemann Pick disease; Sandhoff disease; Tay Sachs disease; cell surface receptors; enzyme deficiency; gangliosidosis; glycosphingolipids; human tissue; laboratory mouse; lipid metabolism; neural degeneration; pathologic process; receptor coupling; sphingolipidosis; sphingolipids; sphingosine

Sphingolipids are key mediators and regulators of cell signaling pathways. Our studies have focused on the actions of two classes of sphingolipids represented by glycosphingolipids (GSLs) and sphingosine-1-phosphate (S1P). Our work is aimed at defining the normal functions of these sphingolipids and understanding their roles in disease processes. GSLs are found in the outer leaflet of the plasma membrane and are concentrated in specialized signaling structures. They are particularly abundant in neuronal cells in the form of gangliosides (sialic acid containing GSLs). Through genetic disruption of genes that encode synthetic enzymes for GSLs, we have created a series of mice that express limited glycosphingolipid structures. We are using these mice to discover the functions of GSLs. When the cellular machinery responsible for GSL degradation is defective, GSL storage diseases result in which profound neurodegeneration occurs. Examples are Tay-Sachs, Sandhoff and Gaucher diseases. S1P is a signaling molecule that is crucial for the regulation of several diverse cellular events, including cell survival, growth, differentiation and calcium mobilization. Recently, numerous studies on S1P have demonstrated its importance in the development of the cardiovascular system and immunity through a family of G protein-coupled receptors (GPCRs), designated S1P1-5. 1. We have shown that S1P also plays a key role in neural development, probably mediated by the S1P1 receptor. We found that simultaneous disruption of the two known sphingosine kinase genes in mice results in a deficiency of S1P, which disturbed angiogenesis and caused neural tube closure defects, followed by embryonic lethality. Dramatic increases in apoptosis and decreases in mitosis were seen in the developing nervous systems of these mutant embryos. Thus, S1P joins a growing list of signaling molecules, such as vascular endothelial growth factor, which regulate the functionally intertwined pathways of angiogenesis and neurogenesis. Our findings not only provide new biological insights into S1P signaling, but also suggest that exploitation of this pathway could lead to the development of novel therapeutic approaches for neurological disease. 2. We have now established a Ugcg allele in mice flanked by loxP sites (floxed). When cre recombinase was expressed in the nervous system under the Nestin promoter, the floxed gene underwent recombination, resulting in a substantial reduction of Ugcg expression and of glycosphingolipid ganglio-series levels. The mice lacking Ugcg in the nervous system show a striking loss of Purkinje cells and abnormal neurologic behavior. The floxed Ugcg allele will facilitate the analysis of the function of glycosphingolipids in normal physiology and in diseases such as diabetes and cancer.

鞘脂是细胞信号传导途径的关键介质和调节剂。我们的研究集中在两类鞘脂的作用，代表鞘糖脂（GSL）和鞘氨醇-1-磷酸（S1 P）。我们的工作旨在定义这些鞘脂的正常功能，并了解它们在疾病过程中的作用。 GSL存在于质膜的外小叶中，并集中在专门的信号结构中。它们以神经节苷脂（含唾液酸的GSL）的形式在神经元细胞中特别丰富。通过对编码GSL合成酶的基因进行遗传破坏，我们创造了一系列表达有限鞘糖脂结构的小鼠。我们正在使用这些小鼠来发现GSL的功能。当负责GSL降解的细胞机制有缺陷时，GSL储存疾病导致发生严重的神经变性。例如Tay-Sachs病、Sandhoff病和Gaucher病。 S1 P是一种信号分子，对于调节多种不同的细胞事件至关重要，包括细胞存活、生长、分化和钙动员。近年来，大量研究表明，S1 P在心血管系统和免疫系统的发展中起着重要作用，它通过一个G蛋白偶联受体（GPCRs）家族，命名为S1 P1 -5。 1.我们已经表明，S1 P在神经发育中也起着关键作用，可能由S1 P1受体介导。我们发现，在小鼠中同时破坏两种已知的鞘氨醇激酶基因会导致S1 P缺乏，这会干扰血管生成并导致神经管闭合缺陷，随后导致胚胎死亡。在这些突变胚胎的神经系统发育中，细胞凋亡急剧增加，有丝分裂减少。因此，S1 P加入了越来越多的信号分子，如血管内皮生长因子，调节血管生成和神经发生的功能交织的途径。我们的研究结果不仅为S1 P信号转导提供了新的生物学见解，而且还表明，利用这一途径可能会导致神经系统疾病新的治疗方法的发展。 2.我们现在已经在小鼠中建立了侧接loxP位点（floxed）的Ugcg等位基因。当Cre重组酶在Nestin启动子下的神经系统中表达时，floxed基因进行重组，导致Ugcg表达和鞘糖脂神经节系列水平的大幅降低。神经系统中缺乏Ugcg的小鼠表现出明显的浦肯野细胞损失和异常的神经行为。floxed的Ugcg等位基因将有助于分析鞘糖脂在正常生理学和疾病如糖尿病和癌症中的功能。