Mechanisms of folate action during nervous system development

项目总结 神经管缺陷(NTD)是人类胎儿最常见的严重出生缺陷之一， 新生儿在美国的总发病率为1/1000，估计为300,000或更多 全球每年都有新生儿出生。NTDS是由于胎儿早期神经管关闭失败所致 发展。遗传和环境因素的结合似乎调节了神经的形成。 管子。值得注意的是，怀孕期间补充叶酸预防NTDS的机制尚不清楚。我们最近 已发表的研究表明，叶酸受体1(Folr1)是叶酸摄取系统之一，定位于根尖 非洲爪哇神经板表面及神经板细胞在神经过程中所必需的根尖收缩 折叠板。此外，我们还发现Folr1与粘着连接成分C-钙粘素和β-1相互作用。 连环蛋白提示叶酸信号可能调节神经管过程中神经板细胞-细胞间的黏附 队形。我们的总体研究目标是阐明神经的细胞和分子机制。 管子编队。我们将检验叶酸参与神经细胞形状变化的假设 在神经形成过程中，通过招募其受体并触发一条新的动态信号通路来进行。这个 第一个具体目标将在于确定叶酸/Folr1促进神经的分子机制 神经管形成过程中板状细胞顶端收缩。我们将确定Folr1的分子机制 调节神经管形成所必需的细胞黏附重塑。在第二个具体目标中，我们将 发现叶酸/Folr1招募的信号通路是神经板细胞顶端所必需的 收缩和神经管形成。我们将通过泛素化途径的得失来探讨泛素化途径。 函数方法和上位性实验。我们将评估叶酸在细胞黏附分子和 表达荧光标记蛋白或细胞报告蛋白的活体成像胚胎的细胞骨架动力学 神经管形成过程中的黏附和细胞骨架成分。我们将使用最先进的方法 包括免疫沉淀物的蛋白质组学、超分辨显微镜、细胞骨架和细胞的报告 黏附动力学和光遗传方法来操纵信号通路。虽然叶酸强化 一直是一项高效的公共卫生措施，在减少非传染性疾病方面缺乏基于机制的认识 NTD预防的问题引发了人们对以下问题的普遍担忧 补充。最佳叶酸补充剂、危险人群和叶酸不敏感型NTDS的治疗 有待完全阐明分子和细胞机制的未解决的临床方面 叶酸在神经管形成中的潜在作用。

Project summary Neural tube defects (NTDs) are among the most common serious birth defects diagnosed in human fetuses and newborns with a combined incidence of ~1/1,000 in the United States and an estimated of 300,000 or more newborns worldwide each year. NTDs result from the failure of neural tube closure during the early fetal development. A combination of genetic and environmental factors appears to regulate the formation of the neural tube. Notably, folate supplementation during pregnancy prevents NTDs by unclear mechanisms. Our recently published study demonstrates that folate receptor 1 (Folr1), one of folate uptake systems, localizes to the apical surface of Xenopus laevis neural plate and is necessary for neural plate cell apical constriction during neural plate folding. Moreover, we find that Folr1 interacts with adherens junction components, C-cadherin and β- catenin suggesting that folate signaling might regulate neural plate cell-cell adhesion during neural tube formation. Our overall research goal is to elucidate the cellular and molecular mechanisms underlying neural tube formation. We will test the hypothesis that folate participates in the changes in cell shape that neural cells undergo during neurulation by recruiting its receptor and triggering a novel and dynamic signaling pathway. The first specific aim will consist in determining the molecular mechanisms underlying folate/Folr1 promotion of neural plate cell apical constriction during neural tube formation. We will identify the molecular mechanisms of Folr1 regulation of cell adhesion remodeling necessary for neural tube formation. In the second specific aim we will discover the signaling pathways recruited by folate/Folr1 that are necessary for neural plate cell apical constriction and neural tube formation. We will interrogate the ubiquitination pathway through gain and loss of function approaches and epistasis experiments. We will assess the role of folate in cell adhesion molecule and cytoskeletal dynamics by live imaging embryos expressing fluorescently tagged proteins or reporters of cell adhesion and cytoskeletal components during neural tube formation. We will use state-of-the-art methodologies including proteomics of immunoprecipitates, super resolution microscopy, reporters of cytoskeletal and cell adhesion dynamics and optogenetic approaches to manipulate signaling pathways. Although folate fortification has been a highly effective public health measure in reducing NTDs, the lack of mechanism-based understanding of NTD prevention leads to general concerns regarding unintended consequences resulting from supplementation. Optimal folate supplementation, risk groups and treatment of folate-insensitive NTDs are some of the unsolved clinical aspects awaiting for the full elucidation of the molecular and cellular mechanisms underlying folate action in neural tube formation.