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

摘要 胎儿酒精谱系障碍（FASD）每年影响美国多达5%的新生儿，并导致终身 身体和行为障碍。神经形成阶段乙醇暴露（人类妊娠约第4周， 小鼠妊娠8 - 10天），与面部和大脑，特别是腹侧 中线结构（例如隔膜、垂体、心室）和生命后期的神经功能变化。这种扩张 类似于在纤毛病遗传性疾病中观察到的CNS和颅面异常， 综合征纤毛病是初级纤毛缺陷的结果，初级纤毛是对 音刺猬（Shh）通路转导和细胞增殖在发育过程中。纤毛功能障碍 某些纤毛病导致Shh的过度激活，导致观察到的CNS异常。以前的工作 提出纤毛相关运动蛋白的突变导致纤毛病表型，并与 乙醇导致大脑变宽（未发表的数据）。在这个提议中，我们使用了一个特征良好的小鼠模型， 的FASD测试的假设，乙醇暴露在神经形成诱导一个"短暂的"纤毛病变， 胚胎，导致纤毛病变和FASD之间的共享表型。目的1分析初级纤毛数 和神经管中的形态学。目标2调查了 这些睫状体缺陷的机制，通过检查纤毛相关基因表达的变化。第三，目标 通过分析神经元形成期乙醇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通路信号传导。初步数据显示乙醇- 暴露的胚胎改变了关键纤毛发生基因的表达， 神经管更多纤毛的存在将导致Shh信号传导上调和异常细胞增殖， 导致观察到的CNS异常。重要的是，这些实验将提供证据支持 改变初级纤毛的数量和功能的神经管作为一种新的途径，通过乙醇 暴露会导致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in cilia-associated motor proteins lead to ciliopathic phenotypes and interact with ethanol to cause wider brains (unpublished data).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.