Autism spectrum disorder (ASD) is currently estimated to affect more than 1% of the world population. For people with ASD, gastrointestinal (GI) distress is a commonly reported but a poorly understood co-occurring symptom. Here, we investigate the physiological basis for GI distress in ASD by studying gut function in a zebrafish model of Phelan-McDermid syndrome (PMS), a condition caused by mutations in the SHANK3 gene. To generate a zebrafish model of PMS, we used CRISPR/Cas9 to introduce clinically related C-terminal frameshift mutations in shank3a and shank3b zebrafish paralogues (shank3abΔC). Because PMS is caused by SHANK3 haploinsufficiency, we assessed the digestive tract (DT) structure and function in zebrafish shank3abΔC+/− heterozygotes. Human SHANK3 mRNA was then used to rescue DT phenotypes in larval zebrafish. Significantly slower rates of DT peristaltic contractions (p < 0.001) with correspondingly prolonged passage time (p < 0.004) occurred in shank3abΔC+/− mutants. Rescue injections of mRNA encoding the longest human SHANK3 isoform into shank3abΔC+/− mutants produced larvae with intestinal bulb emptying similar to wild type (WT), but still deficits in posterior intestinal motility. Serotonin-positive enteroendocrine cells (EECs) were significantly reduced in both shank3abΔC+/− and shank3abΔC−/− mutants (p < 0.05) while enteric neuron counts and overall structure of the DT epithelium, including goblet cell number, were unaffected in shank3abΔC+/− larvae. Our data and rescue experiments support mutations in SHANK3 as causal for GI transit and motility abnormalities. Reductions in serotonin-positive EECs and serotonin-filled ENS boutons suggest an endocrine/neural component to this dysmotility. This is the first study to date demonstrating DT dysmotility in a zebrafish single gene mutant model of ASD.

中文翻译：

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肠运动障碍在斑马鱼（斑马鱼）shank3a; shank3b孤独症的突变体模型

据估计，自闭症谱系障碍（ASD）影响世界人口的1％以上。对于自闭症患者，胃肠道（GI）困扰是一种普遍报道的症状，但鲜为人知。在这里，我们通过研究PHENLAN-McDermid综合征（PMS）的斑马鱼模型中的肠道功能来研究ASD中GI窘迫的生理学基础，该模型是由SHANK3基因突变引起的。为了生成PMS的斑马鱼模型，我们使用CRISPR / Cas9在shank3a和shank3b斑马鱼仿生动物（shank3abΔC）中引入了临床相关的C末端移码突变。因为PMS是由SHANK3单倍体不足引起的，所以我们评估了斑马鱼shank3abΔC+/-杂合子的消化道（DT）结构和功能。然后将人SHANK3 mRNA用于拯救幼虫斑马鱼中的DT表型。在shank3abΔC+/-突变体中，DT蠕动收缩的速率显着降低（p <0.001），且传代时间延长（p <0.004）。向shank3abΔC+/-突变体中急救注射编码最长人类SHANK3同工型的mRNA产生的幼虫，其肠道球茎排空类似于野生型（WT），但后肠蠕动仍然不足。shank3abΔC+/-和shank3abΔC-/-突变体中血清素阳性肠内分泌细胞（EEC）均显着减少（p <0.05），而shank3abΔC+/-的肠神经元计数和DT上皮的整体结构，包括杯状细胞数，均不受影响。幼虫。我们的数据和抢救实验支持SHANK3突变是胃肠道转运和运动异常的原因。血清素阳性EEC和填充血清素ENS的boutons减少表明这种运动障碍的内分泌/神经成分。迄今为止，这是首次证明斑马鱼ASD斑马鱼单基因突变体模型中的DT功能障碍。