Development of a novel animal model to investigate the role of cholesterol metabolism in the development and differentiation

开发一种新型动物模型来研究胆固醇代谢在发育和分化中的作用

• 批准号: 10557104
• 负责人: ISHIBASHI Shun
• 金额: $ 8.7万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10557104/
• 关键词: Development; Cholesterol; Squalene synthase; Gene targeting; Knockout mouse; Hedgehog; Farneso1; Neural tube defect; 発生分化; HMGCoA還元酵素; スクアレン合成酵素; ノックアウアトマウス; ターゲティング; ES細胞; キメラマウス

Squalene synthase (SS) catalyzes the reductive head-to-head condensation of two molecules of farnesyl diphosphate (FPP) to form squalene, the first specific intermediate in the cholesterol biosynthetic pathway. We used gene targeting to knock out the mouse SS gene. The mice heterozygous for the mutation (SS+/-) were apparently normal. SS+/- mice showed 60% reduction in the hepatic mRNA levels of SS compared to SS+/+mice. Consistently, the SS enzymatic activities were reduced by 50% in the liver and testis. Nevertheless, the hepatic cholesterol synthesis was not different between SS+/- and SS+/+ mice and plasma lipoprotein profiles were not different irrespective of the presence of the LDL receptor, indicating that SS is not a rate-limiting enzyme in the cholesterol biosynthetic pathway. The mice homozygous for the disrupted SS gene (SS-/-) were embryonic lethal around midgestation. E9.5-10.5 SS-/- embryos exhibited severe growth retardation and defective neural tube closure. The lethal phenotype was not rescued by supplementing the dams either with dietary squalene or cholesterol. We speculate that cholesterol is required for the development, particularly, of nervous system, and that the chorioallantoic circulatory system is not mature enough to supply the rapidly growing embryos with maternal cholesterol at this developmental stage.

小鳞合酶（SS）催化了两种法尼磷酸盐（FPP）的两个分子的还原性头对头凝结，形成了Speralene，这是胆固醇生物合成途径中的第一个特异性中间体。我们使用基因靶向来淘汰小鼠SS基因。突变（SS +/-）的杂合小鼠显然是正常的。 SS +/-小鼠与SS+/+小鼠相比，SS的肝mRNA水平降低了60％。一致地，在肝脏和睾丸中，SS酶活性减少了50％。然而，SS +/-和SS+/+小鼠之间的肝胆固醇合成并不差异，而血浆脂蛋白曲线概况无关，无论LDL受体的存在如何，这表明SS不是胆固醇生物合理途径的速率限制酶。纯合SS基因（SS - / - ）纯合的小鼠在中间寄生周围是胚胎致死的。 E9.5-10.5 SS - / - 胚胎表现出严重的生长迟缓和有缺陷的神经管闭合。致命的表型未通过补充饮食中的小甲烯或胆固醇来挽救致命的表型。我们推测，尤其是神经系统的发育需要胆固醇，而绒毛膜循环系统还不够成熟，无法在此发育阶段向母体胆固醇提供快速生长的胚胎。

项目成果

Gotoda T, Iizuka Y, Kato N, Osuga J, Bihoreau MT, Murakami T, Yamori Y, Shimano H, Ishibashi S. Yamada N.: "Absence of Cd36 mutation in the original spontaneously hypertensive rats with insulin resistance."Nat. Genet.. 22. 226-228 (1999)

Gotoda T、Iizuka Y、Kato N、Osuga J、Bihoreau MT、Murakami T、Yamori Y、Shimano H、Ishibashi S. Yamada N.：“具有胰岛素抵抗的原始自发性高血压大鼠中不存在 Cd36 突变。”Nat。

Shimano H, Ishibashi S, et al.: "Sterol regulatory element-binding protein-1 as a key transcription factor for nutritional induction of lipogenic enzyme genes"J. Biol. Chem.. 274. 35832-35839 (1999)

Shimano H，Ishibashi S，等人：“甾醇调节元件结合蛋白-1作为脂肪生成酶基因营养诱导的关键转录因子”J。

Yuan X, Ishibashi S, Hatakeyama S, Saito M, Nakayama J, Nikaido R, Haruyama T, Watanabe Y, Iwata H, Iida M, Sugimura H, Yamada N, Ishikawa F.: "The presence of telomeric G-strand tails in the telomerase catalytic subunit TERT knockout mice."Genes Cells. 4

Yuan X, Ishibashi S, Hatakeyama S, Saito M, Nakayama J, Nikaido R, Haruyama T, Watanabe Y, Iwata H, Iida M, Sugimura H, Yamada N, Ishikawa F.：“端粒 G 链尾部的存在

Gotoda T,Ishibashi S,et al.: "Absence of Cd36 mutation in the original spontaneously hypertensive rats with insulin resistanse"Nat.Genet.. 22. 226-228 (1999)

Gotoda T，Ishibashi S，et al.：“具有胰岛素抵抗的原始自发性高血压大鼠中不存在 Cd36 突变”Nat.Genet.. 22. 226-228 (1999)

Gotoda T, Ishibashi S, et al.: "Absence of Cd36 mutation in the original spontaneously hypertensive rats with insulin resistance"Nat. Genet.. 22. 226-8 (1999)

Gotoda T、Ishibashi S 等人：“具有胰岛素抵抗的原始自发性高血压大鼠中不存在 Cd36 突变”Nat。