Development of Molecular Therapy for Carbamoyl Phosphate Synthetase Deficiency

 描述：尿素循环是哺乳动物解氨的主要途径。氨基甲酰磷酸合成酶1(CPS1)缺乏症是一种毁灭性的疾病。在人类中，这种酶缺乏的临床特征是周期性的高氨血症，导致进行性智力障碍和高死亡可能性。本研究旨在建立一种新的氨基甲酰磷酸合成酶缺乏症动物模型，并利用病毒载体建立基于基因的氨基甲酰磷酸合成酶缺乏症的纠正方法。初步数据：我们的研究小组：1)正在开发一种条件性CPS1缺陷基因敲除小鼠；以及2)新生给药后，来自重组辅助性腺病毒载体和腺相关病毒载体的转基因在细胞内和分泌蛋白紊乱导致遗传纠正(血友病A和精氨酸酶缺乏)的动物中均有短期和长期表达。在目标1中，我们将描述一种新的条件基因敲除小鼠的氨基甲酰磷酸合成酶I缺乏症模型，这将有助于开发这种疾病的治疗方法；在目标2中，我们将开发新的基因治疗载体作为CPS1缺乏症的基因替换策略。这些研究将为开发CPS1缺乏症的基因纠正方法提供重要的新工具，并提供一个小动物模型来研究近端尿素循环障碍中高氨血症以外的脑损伤机制。

 DESCRIPTION: The urea cycle is the major pathway for detoxification of ammonia in mammals. Carbamoyl phosphate synthetase 1 (CPS1) deficiency is a devastating condition. In humans, deficiency of this enzyme is characterized clinically by periodic episodes of hyperammonemia resulting in progressive mental impairment and a high likelihood of death. This proposal is to characterize a new animal model of the disorder and develop methods for gene-based correction of carbamoyl phosphate synthetase deficiency with viral vectors. Preliminary data: Our research group has: 1) been developing a conditional CPS1-deficient knockout mouse; and 2) demonstrated short-term and long-term expression of transgenes from both recombinant helper-dependent adenoviral vectors and adeno-associated viral vectors after neonatal administration in animals with disorders of intracellular and secreted proteins of the liver resulting in genetic correction (hemophilia A and arginase deficiency). In Aim 1, we will characterize a novel conditional knockout mouse model of carbamoyl phosphate synthetase I deficiency that will be useful for developing therapies for this disorder; and in Aim 2, we will develop novel gene therapy vectors as gene replacement strategies for CPS1 deficiency. These studies will provide important new tools to develop methods for gene correction of CPS1 deficiency and provide a small animal model to study the mechanism of brain injury beyond that of hyperammonemia in proximal urea cycle disorders.