Stable Zebrafish Models of Autism Spectrum Disorder

描述（由申请人提供）：据估计，自闭症谱系障碍（ASD）目前影响全球1-2.6%的儿童，这表明ASD患病率急剧上升，仅美国每年的成本就计算为1260亿美元（2012年）。由于已知的治疗方法随着诊断年龄的增加而不那么有效，因此解决ASD病因学的突出问题是研究的优先事项。然而，在更常见的哺乳动物模型中，胚胎阶段是不可接近的，因此胚胎发生在我们对ASD病因学的理解中存在重大差距。为了解决这一差距，我们建议生成斑马鱼ASD模型，以明确关注已知导致ASD的突变胚胎的功能后果。而不是调查通常用于定义ASD的社会行为，我们专注于神经解剖学和生理学的内部表型（内表型）。根据这一策略，我们从吗啉敲除实验的初步数据表明，当两个不同的ASD连锁基因SHANK 3和SYNGAP 1中的任何一个在斑马鱼中被敲除时，都有共同的表型。常见的表型包括发育迟缓和类似痴呆的行为。在两种吗啡肽模型中，抑制性GABA能神经元的数量显著减少，这可能解释了这些类似于吗啡肽的行为。发育迟缓、癫痫发作和GABA能信号标志物减少也是ASD患者的特征。为了跟进这些初步研究，我们建议产生稳定的斑马鱼shank 3和syngap 1基因敲除。通过建立和分析稳定的突变株系的GABA能脑回路的发展，我们的目标是确定GABA缺陷的发展机制。从长远来看，这些斑马鱼ASD模型也可以作为发现治疗靶点和环境风险因素的基础。

DESCRIPTION (provided by applicant): Autism Spectrum Disorders (ASDs) are currently estimated to impact 1-2.6% of children world-wide, representing a steep rise in ASD prevalence with annual costs to the United States alone calculated at $126 billion (2012). Because known therapies are less effective with increasing age of diagnosis, addressing outstanding questions about ASD etiology is a research priority. In the more common mammalian models however, embryonic stages are inaccessible therefore embryogenesis presents a major gap in our understanding of ASD etiology. To address this gap, we propose to generate zebrafish ASD models to focus explicitly on functional consequences in embryos of mutations known to cause ASD. Rather than investigate social behaviors typically used to define ASD, we focus on internal phenotypes (endophenotypes) of neuroanatomy and physiology. Following this strategy, our preliminary data from morpholino knockdown experiments demonstrate common phenotypes when either of two distinct ASD-linked genes, SHANK3 and SYNGAP1, is knocked down in zebrafish. Common phenotypes include developmental delay and seizure-like behaviors. These seizure-like behaviors are likely explained by dramatic reductions in the numbers of inhibitory GABAergic neurons in both morphant models. Developmental delay, seizures, and reduced markers of GABAergic signaling are also characteristic of individuals with ASD. To follow up on these preliminary studies we propose to generate stable gene knock-outs of zebrafish shank3 and syngap1. By creating and analyzing stable mutant lines with respect to the development of GABAergic brain circuits, our goal is to determine the developmental mechanisms that underlie GABA deficits. In the long-term, these zebrafish ASD models can also serve as the basis for the discovery of therapeutic targets and environmental risk factors.