芳香族 L-胺基酸脫羧酵素在腦發育與運動功能佔有重要角色

Aromatic L-amino Acid Decarboxylase (AADC) is Crucial for Brain Development and Motor Functions

史德芬(De-Fen Shih)

指導教授 ： 李士傑

國立臺灣大學/生命科學院/生命科學系/博士(2016年)

https://doi.org/10.6342/NTU201610163

摘要

芳香族 L-氨基酸脫羧酶（AADC）缺乏症是一種罕見的兒童神經代謝性疾病。由於缺乏動物模型的參考，其致病機理目前所知甚少。本文主旨為產生AADC缺乏症的斑馬魚模型，以供未來研究AADC相關病理機制之用。原位雜交分析中顯示AADC基因在受精36小時後的斑馬魚胚胎中腦部的骨骺(epiphysis), 藍斑核(locus coeruleus), 間腦兒茶酚胺聚集(dipencephalic catecholaminergic clusters，DC), and 中縫核(raphe nuclei)有特別高的表現。使用AADC抑製劑NSD-1015或反股嗎?（Morphlino, MO）會降低腦容量和抑制身體長度生長。在AADC MO-注射的胚胎的大腦裡也發現細胞凋亡增加與DC部位的神經減少的現象。隨著注射劑量的增加，類癲癇放電也越來越高。就運動部分，AADC MO-注射後胚胎的觸摸反應不太敏感，並減少了游泳活動; 但這個情形是可以同時注射AADC質體改善之。總之，在斑馬魚胚胎中，抑制AADC表現會使腦變小，增加腦中細胞凋亡，並降低活動能力。此等症狀相當類似人類AADC，因此斑馬魚當可用為研究AADC缺乏症的發病機制的動物模式。

關鍵字

AADC缺乏症 ； 多巴胺 ； 斑馬魚 ； 嗎?

並列摘要

Aromatic L-amino acid decarboxylase (AADC) deficiency is a rare pediatric neuro-metabolic disease in children. Due to the lack of an animal model, its pathogenetic mechanism is poorly understood. To study the role of AADC in brain development, a zebrafish model of AADC deficiency was generated. Whole-mount in situ hybridization analysis showed that the aadc gene was specifically expressed in the epiphysis, locus coeruleus, dipencephalic catecholaminergic (DC) clusters, and raphe nuclei of 36-h post-fertilization (hpf) zebrafish embryos. Inhibition of AADC by the inhibitor NSD-1015 or anti-sense morpholino (MO) led to a reduction brain volume and body length. There was an increased apoptosis occurrence in the brain and a loss of DC cluster neurons in AADC morphants (aadc MO-injected embryos). Seizure-like activity was also detected in AADC morphants in a dose-dependent manner. The AADC morphants were less sensitive in touch response and had a reduced swimming activity, and these phenotypes were rescued by injection of aadc plasmids. In conclusion, inhibition of AADC may reduce brain size, increase apoptosis, and reduce motor function in zebrafish. Zebrafish can be a useful model for investigating the pathogenetic mechanisms of AADC deficiency in children.

並列關鍵字

AADC deficiency ； dopamine ； zebrafish ； morpholino

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