Effect of hypercholesteremia on lipid raft-mediated T cell activation

高胆固醇血症对脂筏介导的 T 细胞活化的影响

• 批准号: 14570279
• 负责人: KOSUGI Atsushi
• 金额: $ 2.24万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14570279/
• 关键词: T cells; lipid raft; cholesterol; hypercholesteremia; ganglioside GM1; sphingolipid; Raft

Lipid rafts are highly enriched in cholesterol and sphingolipids (glycosphingolipids (GSLs) and sphingomyelin (SM)). Among these lipid components, cholesterol has a critical function for maintaining raft structure. Cholesterol depletion from cell membranes using drugs, such as methyl-13-cyclodextrin (MβCD), generally results in disruption of raft-mediated cellular functions. Thus, despite some concerns about side effects of the drug on signaling events, this experimental approach has been widely used to verify the importance of cholesterol in raft organization and function.In contrast to many studies manipulating the cholesterol level in lipid rafts, reports that address a role for sphingolipids in raft function are scarce. A previous study demonstrated that reduction of SM levels in Chinese hamster ovary (CHO) mutant cells induced decreased distribution of cholesterol in lipid rafts. Moreover, it was reported that addition of exogenous gangliosides to the culture of Madin-Darby canine … More kidney (MDCK) cells or CHO-K1 cells displaced glycosylphosphatidylinositol (GPI)-anchored proteins from lipid microdomains. All these studies suggested that changes in sphingolipid contents alter raft lipid and protein constituents. However, none of these studies contributed to our understanding of any functional change in membrane rafts by the manipulation of sphingolipid levels. Although an effect of GSL deficiency on functional raft formation has been suggested, whether sphingolipids are essential for raft-mediated signal transduction remains to be addressed. In the present study, we investig ated a role for sphingolipids in raft organization and function in lymphocytes, focusing particularly on a role for GSLs by the usage of a specific GSL synthesis inhibitor, D-PDMP. We demonstrated that the expression state of GPI-anchored proteins is affected by reduction of GSL levels. Further, our results showed that a reduced level of GSLs in membrane rafts modulates signaling through GPI-anchored proteins, but not through the TCR. By comparing the effect of D-PDMP with that of MMCD, we also identified that GSL and cholesterol depletion have distinctly different influences on GPI-anchored proteins in lipid rafts. Less

脂筏富含胆固醇和鞘磷脂(糖鞘脂(GSLS)和鞘磷脂(SM))。在这些脂质成分中，胆固醇对维持RAFT结构起着至关重要的作用。使用甲基-13-环糊精(M-βCD)等药物去除细胞膜上的胆固醇通常会导致RAFT介导的细胞功能中断。因此，尽管药物对信号事件的副作用有一些担忧，但这一实验方法已被广泛用于验证胆固醇在RAFT组织和功能中的重要性。与许多操纵脂筏中胆固醇水平的研究相比，涉及鞘磷脂在RAFT功能中作用的报道很少。先前的研究表明，中国仓鼠卵巢(CHO)突变细胞中SM水平的降低导致胆固醇在脂筏中的分布减少。此外，据报道，在马丁达比犬…的培养中添加外源性神经节苷脂更多的肾脏(MDCK)细胞或CHO-K1细胞取代了脂质微域中的糖基磷脂酰肌醇(GPI)锚定蛋白。所有这些研究表明，鞘脂含量的变化改变了RAFT的脂肪和蛋白质成分。然而，这些研究都没有帮助我们理解通过调节鞘磷脂水平来改变膜筏的任何功能。尽管GSL缺乏对功能性RAFT的形成有影响，但鞘磷脂是否是RAFT介导的信号转导所必需的仍有待研究。在本研究中，我们研究了鞘磷脂在淋巴细胞RAFT组织和功能中的作用，特别是通过使用特定的GSL合成抑制剂D-PDMP对GSLS的作用。我们证明了GPI锚定蛋白的表达状态受到GSL水平降低的影响。此外，我们的结果表明，膜筏中GSLS水平的降低通过GPI锚定蛋白调节信号，而不是通过TCR。通过比较D-PDMP和MMCD的作用，我们还发现GSL和胆固醇消耗对脂筏中GPI锚定蛋白的影响明显不同。较少

项目成果

Inoue H, Miyaji M, Kosugi A, Nagafuku M, Okazaki T, Mimori T, Amakawa R, Fukuhara S, Domae N, Bloom ET, Umehara H: "Lipid rafts as the signaling scaffold for NK cell activation : Tyrosine phosphorylation and association of LAT with PI 3-kinase and PLC-γ f

Inoue H、Miyaji M、Kosugi A、Nagafuku M、Okazaki T、Mimori T、Amakawa R、Fukuhara S、Domae N、Bloom ET、Umehara H：“脂筏作为 NK 细胞激活的信号支架：酪氨酸磷酸化和关联LAT 与 PI 3-激酶和 PLC-γ f

Nagafuku M, Kabayama K, Oka D, Kato A, Tani-Ichi S, Shimada Y, Ohno-Iwashita Y, Yamazaki S, Saito T, Iwabuchi K, Haxnaoka T, Inokuchi JI, Kosugi A: "Reduction of glycosphingolipid levels in lipid rafts affects the expression state and function of glycosyl

Nagafuku M、Kabayama K、Oka D、Kato A、Tani-Ichi S、Shimada Y、Ohno-Iwashita Y、Yamazaki S、Saito T、Iwabuchi K、Haxnaoka T、Inokuchi JI、Kosugi A：“降低脂质中的糖鞘脂水平

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Matsuno Y. et al.: "Nonviral gene gun mediated transfer into the beating heart"ASAIO J.. 49. 641-644 (2003)

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