SOMATIC CELL GENE THERAPY AND NITROGEN FLUX IN UREA CYCLE PATIENTS

尿素循环患者的体细胞基因治疗和氮通量

• 批准号: 6108499
• 负责人: Brendan Lee
• 金额: $ 12.73万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-11 至 1999-09-10
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6108499
• 关键词: arginosuccinate synthetase deficiency; clinical research; cow; disease /disorder model; gene expression; gene mutation; gene therapy; genetic transduction; genotype; human subject; inborn urea cycle disorder; mental retardation; nitrogen metabolism; nonhuman therapy evaluation; transfection /expression vector; urea; urea cycle

The group of inborn errors of hepatic metabolism continue to be a prominent cause of mental retardation because of ineffective treatment strategies. Gene replacement therapy offers the theoretic advantage of correcting the basic protein deficiency. However, progress in hepatocyte directed gene therapy has been limited by questions involving pathophysiologic processes, choice of promoter and vector delivery system, route of delivery, host immune clearance, duration of expression, availability or small and large animal disease models, and quantitative measures of clinical efficacy. The three parts of this proposal attempt to address some of these issues using the group of urea cycle defects a model system. The first goal is to better understand the pathophysiologic disturbances in patients with urea cycle defects by correlating genotype and clinical severity with in vivo measurement of nitrogen flux and ureagenesis, while also developing a quantitative measure for future in vivo gene therapeutic interventions in both animal and humans. Flux through the urea cycle pathway will be measured by quantifying the conversion of [15/N-amide]glutamine to [15/N] urea. This flux will be correlated with genetic status (homozygosity, heterozygosity, hemizygosity), nature of mutation (null versus hypomorphic), and clinical severity (neonatal versus later presentation) in affected patients, heterozygous family members, and normal controls. In the second part of the study, the relative safety and efficacy of first generation (E1a deleted) and second generation (E1a/E2a deleted and all coding sequence deleted) adenovirus vectors will be determined after intravenous (i.v.) delivery in animals. In addition, potential avenues permitting long term transgene expression will be investigated. The efficacy of transient immunosuppression for the readministration of viral vectors will be evaluated, and the potential use of mariner transposon elements in mediating transgene integration in a host mammalian genome will be studied. In the third part, the urea cycle disorders, specifically murine and bovine models of citrullinemia, will be used a model systems in applying these basic findings to a clinical setting. The efficacy of the hybrid, ubiquitously active, CAG and liver-specific human albumin promoters will be compared in vivo. These data will form the preclinical basis for designing phase I clinical trials involving gene therapy in urea cycle patients. These results together will also be more generally applicable to other inborn errors of hepatocyte metabolism and to the production of extracellular products by hepatocytes. Early and long term biochemical correction would be expected to greatly decrease the great neurologic morbidity associated with these conditions.

先天性肝代谢缺陷组仍是一个值得关注的问题。 精神发育迟滞的突出原因是治疗无效 战略布局基因替代疗法提供了理论上的优势， 纠正碱性蛋白质缺乏。然而，肝细胞的进展 定向基因治疗受到一些问题的限制， 病理生理过程，启动子和载体递送系统的选择， 递送途径，宿主免疫清除，表达持续时间， 可用性或小型和大型动物疾病模型，以及定量 临床疗效指标。本提案的三个部分试图 使用尿素循环缺陷组模型解决其中的一些问题 系统第一个目标是更好地理解病理生理学 尿素循环缺陷患者的相关基因型紊乱 和临床严重程度，体内测量氮通量， 尿素生成，同时也为未来的发展制定了定量措施， 在动物和人类中的体内基因治疗干预。通量 将通过量化尿素循环途径来测量 [15/N-酰胺]谷氨酰胺转化为[15/N]尿素。这一通量将是 与遗传状态（纯合性，杂合性， 半合子）、突变性质（无效与亚纯型）和临床 受影响患者的严重程度（新生儿与后期表现）， 杂合子家族成员和正常对照。第二部分 研究中，第一代（E1 a）的相对安全性和有效性 缺失）和第二代（E1 a/E2 a缺失和所有编码序列 缺失的）腺病毒载体将在静脉内（i. v.） 在动物中分娩。此外，潜在的途径，允许长期 将研究转基因表达。瞬态的功效 用于病毒载体再给药的免疫抑制将是 评估，和水手转座子元件的潜在用途， 介导宿主哺乳动物基因组中的转基因整合将是 研究了在第三部分，尿素循环障碍，特别是小鼠， 和牛瓜氨酸血症模型，将被用作模型系统， 将这些基本发现应用于临床环境。的功效 杂合、普遍活性、CAG和肝特异性人白蛋白 将在体内比较启动子。这些数据将形成临床前 设计涉及尿素基因治疗的I期临床试验的基础 循环病人这些结果加在一起也将更普遍 适用于肝细胞代谢的其他先天性缺陷， 肝细胞产生细胞外产物。早期和长期 生物化学校正将有望大大减少 与这些病症相关的神经系统疾病。