Regulation of cell fate and function by sterol homeostasis

项目总结 胆固醇动态平衡的丧失与许多神经发育和神经退行性疾病有关 胆固醇介导的影响的确切机制尚不清楚。在继承时 已知胆固醇合成酶中的突变会导致神经发育缺陷， 这些生化缺陷导致的细胞表型背后的机制在很大程度上仍不清楚 在细胞和功能层面。因此，研究描绘了胆固醇代谢在 神经发育和功能可能会对我们对潜在共同疾病的理解产生重大影响 疾病的发病机制。显示胆固醇生化缺陷的干细胞模型 合成途径代表了一种新的生物学模型来研究异常的甾醇水平和 导致细胞和功能缺陷的信号事件。使用诱导多能干细胞(IPSC)模型 最近，我们展示了DHCR7和SC5D突变，发现了固醇生物合成的独特调节作用 在介导Wnt/β-连环蛋白信号转导的蛋白质之间的功能相互作用。在这项建议中，我们将 检验胆固醇合成缺陷在干细胞水平上抑制正常神经发育的假设 通过抑制蛋白质之间的相互作用，将分化模式转变为神经细胞类型 在抑制突触功能的同时减少神经胶质细胞的损失。该项目的目标1将利用基因组测序和 人类IPSC衍生物和啮齿动物模型的功能研究，以确定胆固醇稳态缺陷 规范神经规范和功能。目标2将把改变的胆固醇的细胞效应联系起来 蛋白质-脂类生化分析中蛋白质-蛋白质相互作用中断的动态平衡 体内细胞模型还将定义动力学、特异性和下游信号事件 是由胆固醇缺陷引起的。这些实验将极大地促进我们对 胆固醇及其相关信号在调节神经发育和神经元功能中的作用 阐明常见神经学中胆固醇稳态变化的机制基础 疾病。

PROJECT SUMMARY Loss of cholesterol homeostasis has been associated with a host of neurodevelopmental and neurodegenerative disorders, though the precise mechanisms underlying cholesterol-mediated effects are unclear. While inherited mutations within cholesterol synthetic enzymes are known to induce neurodevelopmental deficits, the mechanisms behind cellular phenotypes resulting from these biochemical deficits remain largely undefined at the cellular and functional level. Therefore, studies delineating the role of cholesterol metabolism in neurodevelopment and function could have a significant impact on our understanding of potential common mechanisms of disease pathogenesis. Stem cell models exhibiting biochemical defects in the cholesterol synthetic pathway represent a novel biological model to study interactions between abnormal sterol levels and signaling events leading to cellular and functional deficits. Using induced pluripotent stem cell (iPSC) models exhibiting DHCR7 and SC5D mutations, we recently uncovered a unique regulatory role for sterol biosynthesis in the functional interactions between proteins mediating Wnt/β-catenin signaling. Within this proposal, we will test the hypothesis that defects in cholesterol synthesis inhibit normal neurodevelopment at the stem cell level through inhibition of protein-protein interactions, shifting differentiation patterns toward neuronal cell types at the expense of glial cells while inhibiting synaptic function. Aim 1 of this project will utilize genomic sequencing and functional studies in human iPSC derivatives and rodent models to define how defects in cholesterol homeostasis regulate neural specification and function. Aim 2 will correlate the cellular effects of altered cholesterol homeostasis with disrupted protein-protein interactions through biochemical analyses of protein-lipid interactions., In vivo cellular models will also define the kinetics, specificity, and downstream signaling events resulting from cholesterol defects. These experiments will significantly advance our understanding of the role of cholesterol and associated signaling in regulating neurodevelopment and neuronal function, while potentially elucidating the mechanistic underpinnings of cholesterol homeostatic changes in common neurological diseases.