HUMAN ARGINASE AND ARGINASE DEFICIENCY

该提案的重点是研究和开发人类辅酶I（AI）缺乏症和高维生素血症的小鼠基因敲除模型，高维生素血症是一种导致神经和智力退化并导致智力迟钝的疾病。该模型将用于阐明人类两种精氨酸酶基因（AI和AII）的功能、调节和进化，并阐明AI缺乏的病理学和病理生理学。长期目标是设计策略以在这些患者中替代乙酰胆碱酯酶或以其他方式减轻高乙酰胆碱血症的影响。这些将包括基因治疗和诱导AII或“自体酶替代疗法”。本实验对AI缺陷型高氨血症小鼠进行保护性治疗后的生化、分子生物学、病理学等方面的研究。所采用的方法包括：血浆和组织氨基酸测量;酶测定;免疫沉淀;免疫组织化学;原位杂交;动物行为测试;和组织培养。研究将测试两种不同的假设，高胆固醇血症的神经损伤，过量的一氧化氮（NO）的生产和增加的神经递质，谷氨酸和/或γ氨基丁酸（GABA）的合成。AI和AII敲除动物将用于探索这两种酶在炎症细胞、前列腺功能和肾脏生物化学中的作用。在不同组织中表达一种或另一种转基因将在这些研究中发挥重要作用。该项目利用独特的模型，在一个有利的时间，在一个理想的环境和理想的合作者，研究导致智力迟钝的代谢疾病的影响，并通过基因操作治疗。这些研究的结果应提供与大量此类疾病相关的信息。

This proposal focuses on the study and exploitation of the mouse knockout model for human arginase I (AI) deficiency and hyperargininemia, a condition which causes neurological and intellectual deterioration and which results in mental retardation. The model will be used to elucidate the function, regulation and evolution of the two arginase genes in man (AI and AII) and to elucidate the pathology and pathophysiology of AI deficiency. The long term goal is to devise strategies to replace arginase in these patients or otherwise mitigate the impact of the hyperargininemia. These will include gene therapy and induction of AII or "autoenzyme replacement therapy". The biochemistry, molecular biology, pathology of the AI-deficient hyperarginemic mouse after protecting it from hyperammonemia will be studied. Approaches used include: plasma and tissue amino acid measurement; enzyme assay; immunoprecipitation; immunohistochemistry; in situ hybridization; animal behavioral testing; and tissue culture. Studies will test two distinct hypotheses for the neurological damage in hyperargininemia, excess nitric oxide (NO) production and increased synthesis of the neurotransmitters, glutamate and/or gamma aminobutyric acid (GABA). The AI and AII knockout animals will e used to explore the role of the two arginases in inflammatory cells, prostate function and kidney biochemistry. Expression of one or the other arginase transgenes in different tissues will play a prominent role in these studies. This project exploits unique models, at a propitious time, in an ideal environment and with ideal collaborators, to study the effects of a metabolic disease that causes mental retardation, and its treatment by gene manipulation. Results from these studies should provide relevant to a larger number of disorders of this type.