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.

角鲨烯合酶（SS）催化两个分子的法呢基二磷酸（FPP）的还原性头对头缩合以形成角鲨烯，角鲨烯是胆固醇生物合成途径中的第一个特异性中间体。我们使用基因靶向敲除小鼠SS基因。突变杂合子（SS+/-）小鼠明显正常。与SS+/+小鼠相比，SS+/-小鼠显示SS的肝脏mRNA水平降低60%。肝脏和睾丸中SS酶活性降低50%。然而，SS+/-和SS+/+小鼠之间的肝脏胆固醇合成没有差异，并且无论是否存在LDL受体，血浆脂蛋白谱都没有差异，表明SS不是胆固醇生物合成途径中的限速酶。SS基因纯合子小鼠（SS-/-）在妊娠中期左右是胚胎致死的。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。通过向母鼠补充膳食角鲨烯或胆固醇，致死表型没有得到挽救。我们推测，胆固醇是必需的发展，特别是神经系统，和绒毛尿囊循环系统是不够成熟，以提供快速增长的胚胎与母体胆固醇在这个发展阶段。

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 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。

Tozawa R, Ishibashi S, Osuga J, Yagyu H, Oka T, Chen Z, Ohashi K, Perrey S, Shionoiri F, Yahagi N, Harada K, Gotoda T, Yazaki Y, Yamada: "Embryonic Lethality and Defective Neural Tube Closure in Mice Lacking Squalene Synthase"J. Biol. Chem.. 274. 30843-30

Tozawa R、Ishibashi S、Osuga J、Yagyu H、Oka T、Chen Z、Ohashi K、Perrey S、Shionoiri F、Yahagi N、Harada K、Gotoda T、Yazaki Y、Yamada：“胚胎致死性和有缺陷的神经管闭合