Role of Cholesterol Biosynthesis in Development

胆固醇生物合成在发育中的作用

• 批准号: 9767244
• 负责人: SHAILENDRA BHANUBHAI PATEL
• 金额: $ 11.76万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9767244
• 关键词: 7-dehydrocholesterol reductase; Address; Affect; Alleles; Basic Science; Biochemical; Birth; Brain; Cholesterol Homeostasis; Clinical; Clinical Sciences; Collaborations; Congenital Abnormality; Defect; Desmosterol; Development; Dorsal; Dysmorphology; Embryo; Embryology; Embryonic Development; Enzymes; Face; Genes; Genetic; Goals; Human; Hydroxysteroids; Lead; Membrane Microdomains; Metabolism; Molecular; Mus; Mutation; Neuraxis; Oxidoreductase; Pathway interactions; Perinatal mortality demographics; Phenotype; Positioning Attribute; Proteins; Proteome; Research Personnel; Role; Squalene; Sterols; Structural Congenital Anomalies; Structure; Syndrome; Telencephalon; Tissues; brain tissue; cholesterol biosynthesis; craniofacial; craniofacial tissue; enzyme biosynthesis; experimental study; interdisciplinary approach; interest; malformation; mutant; myelination; nervous system development; neurogenesis; novel; postnatal; prevent; skeletal; tool

Genetic defects in the cholesterol bio-synthesis pathway lead to a spectrum of human dysmorphology syndromes with a key common theme of altered craniofacial, skeletal and central nervous system (CNS) development. A deep mechanistic understanding of how these malformations arise will require a multi- disciplinary approach. As part of this R03 to “establish basic science-clinical collaborations to understand structural birth defects,” we will merge the expertise of three teams at the interface of genetics, embryology and sterol metabolism. We will combine clinical acumen and biochemical expertise with molecular embryology to synergistically approach the question of how sterol metabolism defects lead to brain and craniofacial birth defects. We will focus specifically on three enzymes in the post-squalene portion of the cholesterol biosynthesis pathway: hydroxysteroid (17-beta) dehydrogenase 7 (Hsd17b7), 24-dehydrocholesterol reductase (Dhcr24) and 7-dehydrocholesterol reductase (Dhcr7). These are neighboring enzymes in the latter portion of the pathway, but have very different phenotypes when ablated. The rationale for this proposal is that the molecular basis for these structural birth defects in mouse and humans has not been fully elucidated. Furthermore, detailed analysis of the mouse CNS phenotypes after birth has been prevented by perinatal death of the null mutants. Our central hypothesis is that the differing phenotypes within the spectrum of cholesterol metabolism errors occur because defects at different steps of the pathway lead to the accumulation of different sterol intermediates and/or altered lipid raft composition, which then affect embryonic development differently. We have collected and generated 5 mouse alleles (Hsd17b7rudolph, Dhcr24null, Dhcr7null, Dhcr24flox, Dhcr7flox and) to specifically address this hypothesis in this exploratory proposal. In addition, we propose to generate new tools to further develop our overarching hypothesis. We propose to address this hypothesis with two specific aims: (1). Analysis of sterols and lipid rafts in developing brains and faces upon loss of Hsd17b7, Dhcr24, and Dhcr7. (2). Determine the consequences for loss of cholesterol biosynthesis genes Hsd17b7, Dhcr24, and Dhcr7 in the cortex. The experiments in this proposal will accomplish two goals: (1) We will substantially increase our understanding of the effects of loss of three crucial cholesterol biosynthesis enzymes on CNS development. These preliminary studies and the novel Hsd17b7 allele will position us to address even more mechanistic hypotheses about the role of these enzymes, and sterol metabolism more broadly, in congenital structural brain defects, (2) We will establish an effective and demonstrable collaboration between an embryologist, a clinician researcher and an expert in sterol analysis with a shared interest in the role of sterol metabolism in structural birth defects. !

胆固醇生物合成途径中的遗传缺陷导致人类畸形学频谱 具有改变颅面，骨骼和中枢神经系统（CNS）的关键常见主题的综合症 发展。对这些畸形将如何需要多种畸形的深刻理解 纪律方法。作为此R03的一部分 结构性先天缺陷，”我们将在遗传学界面上合并三支团队的专业知识 和固醇代谢。我们将结合临床敏锐度和生化专业知识与分子胚胎学 为了协同解决立体代谢缺陷如何导致大脑和颅面出生的问题 缺陷。我们将专门针对胆固醇后平方的三种酶 生物合成途径：羟基固醇（17-β）脱氢酶7（HSD17B7），24-脱氢胆固醇 还原酶（DHCR24）和7-脱氢胆固醇降低酶（DHCR7）。这些是后者的相邻酶 路径的一部分，但在消融时具有非常不同的表型。该提议的理由是 小鼠和人类这些结构性先天缺陷的分子基础尚未完全阐明。 此外，围产期预防了小鼠CNS表型的详细分析 无效突变体的死亡。我们的中心假设是，在频谱中的分化表型 发生胆固醇代谢错误是因为途径不同步骤的缺陷导致 不同立体声中间体和/或改变脂质筏的组合物的积累，这会影响 胚胎发育的不同。我们已经收集并生成了5个小鼠等位基因（HSD17B7Rudolph， DHCR24NULL，DHCR7NULL，DHCR24FLOX，DHCR7FLOX和）在此探索性中专门解决了这一假设 提议。此外，我们建议生成新的工具，以进一步发展我们的总体假设。我们 提议以两个具体的目的解决这一假设：（1）。立体声和脂质筏的分析 损失HSD17B7，DHCR24和DHCR7的大脑和面部。 （2）。确定损失的后果 皮质中的胆固醇生物合成基因HSD17B7，DHCR24和DHCR7。该提案中的实验 将实现两个目标：（1）我们将大大提高我们对三个损失影响的理解 CNS发育中关键的胆固醇生物合成酶。这些初步研究和小说 HSD17B7等位基因将使我们定位以解决有关这些作用的更多机械假设 酶和固醇代谢更广泛，在先天性结构性脑缺陷中，（2）我们将建立一个 胚胎学家，临床研究人员和专家 固醇分析对固醇代谢在结构出生缺陷中的作用具有共同的兴趣。 呢