Primary cilia number and function in the neural tube in a mouse model of FASD

摘要 在美国，胎儿酒精谱系障碍(FASD)每年影响高达5%的新生儿，并导致终生 身体和行为障碍。神经形成期酒精暴露(~人类怀孕4周， 怀孕8-10天)，与面部和大脑，特别是腹侧的扩大有关 中线结构(如隔膜、脑垂体、脑室)和以后生活中的神经功能变化。这一扩张 与Joubert‘s等纤毛遗传性疾病中观察到的中枢神经系统和头面部异常相似 综合症。纤毛病是初级纤毛缺陷的结果，初级纤毛是一种静止的感觉细胞器，对 Sonic hedgehog(Shh)信号转导与发育过程中的细胞增殖。纤毛功能障碍 一些纤毛病变导致Shh过度激活，导致观察到的中枢神经系统异常。以前的工作 已经提出纤毛相关马达蛋白的突变导致纤毛病变的表型，并与 乙醇能使大脑更宽广(未发表的数据)。在这个方案中，我们使用了一个特征良好的小鼠模型 FASD的一项研究，以验证在神经形成过程中酒精暴露可导致大鼠短暂性纤毛病变的假说。 胚胎，导致纤毛病和FASD具有相同的表型。目标1分析初级纤毛数量 神经形成期酒精暴露后神经管的形态变化。AIM 2调查了 通过检测纤毛相关基因表达的变化来探讨这些纤毛缺陷的机制。最后，目标3 通过分析神经形成期酒精暴露是否改变纤毛的稳定性和功能 微管蛋白翻译后修饰和Shh通路信号转导。初步数据表明，乙醇- 暴露的胚胎改变了关键的纤毛发生基因的表达，并增加了纤毛的数量 神经管。更多的纤毛会导致Shh信号上调和细胞异常增殖， 导致观察到的中枢神经系统异常。重要的是，这些实验将提供证据支持 神经管中初级纤毛数量和功能的变化是乙醇通过的一种新途径 暴露于空气中会导致FASD症状。

Abstract Fetal Alcohol Spectrum Disorders (FASD) affects up to 5% of births in the US each year and results in life-long physical and behavioral impairments. Neurulation-stage ethanol exposure (~ 4th week of pregnancy in humans, gestational days 8-10 in mice), is associated with a widening of the face and brain, particularly the ventral midline structures (e.g. septum, pituitary, ventricles), and neurofunctional changes later in life. This expansion is similar to the CNS and craniofacial abnormalities observed in ciliopathic genetic disorders such as Joubert’s syndrome. Ciliopathies are a consequence of defects in primary cilia, immotile sensory organelles critical for sonic hedgehog (Shh) pathway transduction and cell proliferation during development. Cilia dysfunction in some ciliopathies results in an overactivation of Shh, leading to the observed CNS anomalies. Previous work has suggested that mutations in cilia-associated motor proteins lead to ciliopathic phenotypes and interact with ethanol to cause wider brains (unpublished data). In this proposal, we use a well-characterized mouse model of FASD to test the hypothesis that ethanol exposure during neurulation induces a “transient” ciliopathy in the embryo, leading to the shared phenotype between ciliopathies and FASD. Aim 1 analyzes primary cilia number and morphology in the neural tube following neurulation-stage ethanol exposure. Aim 2 investigates the mechanisms of these ciliary defects by examining cilia-related gene expression changes. Finally, Aim 3 examines whether neurulation-stage ethanol exposure alters cilia stability and function through analysis of tubulin post-translational modifications and Shh pathway signaling. Preliminary data suggest that ethanol- exposed embryos have altered expression of key ciliogenesis genes and an increased number of cilia in the neural tube. Presence of more cilia would lead to upregulated Shh signaling and abnormal cell proliferation, causing the observed CNS abnormalities. Importantly, these experiments will provide evidence supporting alterations to primary cilia number and function in the neural tube as a novel pathway through which ethanol exposure causes symptoms of FASD.