The role of plasma membrane type sialidase gene Neu3 on the pathogenesis of type 2 diabetes mellitusin Japanese.

质膜型唾液酸酶基因 Neu3 在日本 2 型糖尿病发病机制中的作用

• 批准号: 14370333
• 负责人: SUZUKI Susumu
• 金额: $ 9.02万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 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-14370333/
• 关键词: Diabetes; Ganglioside; Sialidase; Insulin resistance; Transgenic mice; Knockout mice; Insulin receptor; Insulin receptor substrate 1; タンスジェニックマウス

Gangliosides are a family of sialic acid-containing glycosphingolipids present in the cell surface membranes. Several lines of evidence suggest their important functional roles in regulating a wide range of biological processes including cell growth, cell differentiation, and transmembrane signaling. Plasma membrane-associated sialidase (Neu3) is a key enzyme for ganglioside hydrolysis, thereby playing crucial roles in regulation of cell surface functions.We have investigated effects of overexpression in transgenic mice by using the human NEU3 cDNA. We demonstrated that mice overexpressing the human NEU3 develop diabetic phenotype associated with hyperinsulinemia, islet hyperplasia, and increased beta-cell mass. As compared with the wild type, insulin-stimulated phosphorylation of the insulin receptor (IR) and insulin receptor substrate I was significantly reduced, and activities of phosphatidylinositol 3-kinase and glycogen synthase were low in transgenic muscle. IR phosphorylation wa … More s already attenuated in the younger mice before manifestation of cemia. Transient transfection of NEU3 into 3T3-L1 adipocytes and L6 myocytes caused a significant decrease in IR signaling. In response to insulin, NEU3 was found to undergo tyrosine phosphorylation and subsequent association with the Grb2 protein, thus being activated and causing negative regulation of insulin signaling. In fact, accumulation of GM1 and GM2, the possible sialidase products in transgenic tissues, caused inhibition of IR phosphorylation in vitro, and blocking of association with Grb2 resulted in reversion of impaired insulin signaling in L6 cells. The data indicate that NEU3 indeed participates in the control of insulin signaling, probably via modulation of gangliosides and interaction with Grb2, and that the mice can serve as a valuable model for human insulin-resistant diabetes.We also investigate the possible contribution of single nucleotide polymorphisms (SNPs) in NEU3 to the development of type 2 diabetes. We surveyed SNPs in the NEU3 gene in 298 Japanese subjects with type 2 diabetes mellitus and two control Japanese populations : one consisting of 148 elderly subjects who met stringent criteria for being non-diabetic including age above 60 years and no evidence of diabetes (HbA1c<5.6%), and another 308 subjects with normal glucose tolerance (NGT). We identified eight SNPs with and five SNPs without amino acid substitutions in their coding regions. The allele frequency of one of SNPs was significantly higher in type 2 diabetic patients than in both elderly normal and NGT subjects, whereas the allele frequency of other SNPs was essentially identical in these three groups. Furthermore, in the NGT subjects, the SNP was associated with a significantly lower insulin sensitivity index on oral glucose tolerance test. These results strongly suggest that, in Japanese, the SNP in the NEU32 gene is associated with the development of type 2 diabetes, via reduced insulin signaling. Less

神经节苷脂是存在于细胞表面膜中的一类含唾液酸的鞘糖脂。多项证据表明它们在调节广泛的生物过程（包括细胞生长、细胞分化和跨膜信号传导）方面发挥着重要的功能作用。质膜相关唾液酸酶 (Neu3) 是神经节苷脂水解的关键酶，因此在细胞表面功能的调节中发挥着至关重要的作用。我们利用人 NEU3 cDNA 研究了转基因小鼠中过度表达的影响。我们证明，过度表达人类 NEU3 的小鼠会出现与高胰岛素血症、胰岛增生和 β 细胞质量增加相关的糖尿病表型。与野生型相比，转基因肌肉中胰岛素刺激的胰岛素受体（IR）和胰岛素受体底物I的磷酸化显着降低，并且磷脂酰肌醇3-激酶和糖原合成酶的活性较低。在出现 cemia 之前，年轻小鼠的 IR 磷酸化已经减弱。将 NEU3 瞬时转染至 3T3-L1 脂肪细胞和 L6 肌细胞中导致 IR 信号显着减少。为了响应胰岛素，NEU3 发生酪氨酸磷酸化，随后与 Grb2 蛋白结合，从而被激活并导致胰岛素信号传导的负调节。事实上，GM1和GM2（转基因组织中可能的唾液酸酶产物）的积累在体外引起IR磷酸化的抑制，并且阻断与Grb2的结合导致L6细胞中受损的胰岛素信号的逆转。数据表明，NEU3 确实参与了胰岛素信号传导的控制，可能是通过神经节苷脂的调节以及与 Grb2 的相互作用，并且小鼠可以作为人类胰岛素抵抗糖尿病的有价值的模型。我们还研究了 NEU3 中的单核苷酸多态性 (SNP) 对 2 型糖尿病的发展的可能贡献。我们调查了 298 名患有 2 型糖尿病的日本受试者和两个对照日本人群的 NEU3 基因中的 S​​NP：其中一组由 148 名符合非糖尿病严格标准的老年受试者组成，包括年龄超过 60 岁且没有糖尿病证据 (HbA1c<5.6%)，另外 308 名具有正常糖耐量 (NGT) 的受试者。我们鉴定了 8 个编码区有氨基酸取代的 SNP 和 5 个没有氨基酸取代的 SNP。 2 型糖尿病患者中其中一种 SNP 的等位基因频率显着高于老年正常受试者和 NGT 受试者，而其他 SNP 的等位基因频率在这三组中基本相同。此外，在 NGT 受试者中，SNP 与口服葡萄糖耐量试验中胰岛素敏感性指数显着降低相关。这些结果强烈表明，在日语中，NEU32 基因中的 S​​NP 通过减少胰岛素信号传导与 2 型糖尿病的发生相关。较少的

项目成果

Sasaki A, Hata K, Suzuki S, et al.: "Overexpression of plasma membrane-associated sialidase attenuates insulin signaling in transgenic mice"J Biol Chem. 278. 27896-27902 (2003)

Sasaki A、Hata K、Suzuki S 等人：“质膜相关唾液酸酶的过度表达会减弱转基因小鼠中的胰岛素信号”J Biol Chem。

Suzuki S, Oka Y, Kadowaki T, Kanatsuka A, et al.: "Clinical features of diabetes mellitus with the mitochondrial DNA 3243 (A-G) mutation in Japan"Diabetes Research Clinical Practice. 59・3. 207-217 (2003)

Suzuki S、Oka Y、Kadowaki T、Kanatsuka A 等：“日本线粒体 DNA 3243 (A-G) 突变的糖尿病的临床特征”糖尿病研究临床实践 59·3 (2003)。

Suzuki Y, Suzuki S, Hinokio Y, Taniyama M, Atsumi Y, et al.: "Multiple Tumors in Mitochondrial Diabetes Associated with tRNA Leu(UUR) Mutation at Position 3264"Diabetes Care. 26(in press). (2003)

Suzuki Y、Suzuki S、Hinokio Y、Taniyama M、Atsumi Y 等人：“与 3264 位 tRNA Leu (UUR) 突变相关的线粒体糖尿病中的多发肿瘤”糖尿病护理。

Wenyi Z, Suzuki S, Hirai M, Hinokio Y, Tanizawa Y, et al.: "Role of Urotensin II Gene in Genetic Susceptibility to Type 2 Diabetes Mellitus in Japanese"Diabetologia. 47(in press). (2003)

Wenyi Z、Suzuki S、Hirai M、Hinokio Y、Tanizawa Y 等：“尾加压素 II 基因在日本 2 型糖尿病遗传易感性中的作用”糖尿病学。

Sasaki A, Hata K, Suzuki S, et al.: "Overexpression of plasma membrane-associated sialidase attenuates insulin signaling in transgenic mice."J Biol Chem. 278. 27896-27902 (2003)

Sasaki A、Hata K、Suzuki S 等人：“质膜相关唾液酸酶的过度表达会减弱转基因小鼠中的胰岛素信号传导。”J Biol Chem。