Augmented Phenylalanine Clearance by Muscles as Novel Therapy for Phenylketonuria

肌肉增强苯丙氨酸清除率作为苯丙酮尿症的新疗法

基本信息

批准号：
8011166
负责人：
Cary O. Harding
金额：
$ 32.52万
依托单位：
OREGON HEALTH & SCIENCE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-01-15 至 2013-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8011166
关键词：
6-pyruvoyltetrahydropterin synthase Adverse effects Ally Amino Acids Animal Model Attenuated Birth Blood Blood Circulation Body Weight Breeding Classical phenylketonuria Complementary DNA Development Disease Early treatment Elements Enzymes Functional disorder Future GTP Cyclohydrolase Goals Hindlimb Human Hydroxylation Hyperphenylalaninaemias Inborn Errors of Metabolism Inborn Genetic Diseases Inherited Injection of therapeutic agent Intramuscular Injections Intravenous Journals Lead Learning Limb structure Liver Manuscripts Measures Mediating Metabolic Diseases Metabolism Methods Modeling Modification Molecular Mus Muscle Mutation Neonatal Screening Neurologic Pathology Pathway interactions Phenotype Phenylalanine Phenylalanine Ammonia-Lyase Phenylalanine Hydroxylase Phenylalanine Metabolism Pathway Phenylketonurias Proteins Pterins Publications Recombinant adeno-associated virus (rAAV)Recombinants Research Personnel Safety Serotyping Skeletal Muscle System Techniques Testing Tissues Transcriptional Regulation Transgenes Transgenic Mice Vascular blood supply Veins Virus Yeasts alternative treatment cofactor disease phenotype enzyme deficiency fatty acid metabolism gene therapy immunogenic mouse model novel novel therapeutic intervention organic acid plasmid DNA promoter public health relevance research study restoration success synthetic enzyme tandem mass spectrometry tetrahydrobiopterin therapeutic gene uptake vector

项目摘要

DESCRIPTION (provided by applicant): The overall goal of this project is to explore muscle-directed gene therapy as an alternative treatment for inborn errors of metabolism (IEM) detected by newborn screening. More specifically, the investigators will focus their efforts upon phenylalanine hydroxylase (PAH)-deficient Pahenu2 mice, a model of human phenylketonuria (PKU), and will evaluate expression of a phenylalanine (Phe) metabolizing system in muscle as a potential novel therapeutic approach to this disorder. For many IEM, disease pathology is due to effects of a circulating toxic metabolite rather than any direct tissue-specific effect from the enzyme deficiency. For example, PAH is primarily expressed in liver, but the pathology associated with PKU is entirely due to effects of circulating Phe; the liver itself is unaffected by PAH deficiency. Any treatment that achieves permanent reduction of blood Phe will effectively ameliorate the PKU phenotype. The investigators' hypothesized that expression of a robust Phe-metabolizing system in skeletal muscle will augment normal anabolic Phe uptake in muscle, effectively metabolize circulating Phe and correct hyperphenylalaninemia. They will explore two different Phe-metabolizing systems: coordinate expression in muscle of PAH along with the enzymes GTP cyclohydrolase 1 (GTPCH) and 6-pyruvoyltetrahydropterin synthase (PTPS), both elements of the tetrahydrobiopterin (BH4) synthetic pathway, to provide the BH4 cofactor necessary to support Phe hydroxylation or expression of phenylalanine ammonia lyase (PAL), a Phe-metabolizing enzyme that does not require any external cofactors. In Specific Aim 1, the investigators will employ standard germline modification methods to develop transgenic mice that express a Phe metabolizing system throughout all skeletal muscle. These mice will be bred to Pahenu2 mice to yield progeny that lack liver PAH activity but express the Phe metabolizing system in muscle. Phe clearance will be assessed in these progeny. In Specific Aim 2, they will separately employ either recombinant adenoassociated virus serotype 1 vectors (rAAV2/1) or naked plasmid DNA vectors delivered by hydrodynamic limb vein injection to induce expression of a Phe metabolizing system directly in hindlimb muscles of Pahenu2 mice. It is proposed that muscle expression of PAH along with elements of the BH4 synthetic pathway or of PAL alone will lead to correction of hyperphenylalaninemia in Pahenu2 mice. PUBLIC HEALTH RELEVANCE: The overall goal of this project is to develop novel gene therapy approach for the treatment of inherited metabolic disorders that are detected at birth through newborn screening. The investigators will delineate muscle gene therapy as a new treatment approach to inherited metabolic disorders, and will focus specifically upon a mouse model of the human disorder phenylketonuria (PKU), one of the most common metabolic diseases.

描述（由申请人提供）：该项目的总体目标是探索肌肉定向基因疗法作为新生儿筛查检测到的先天性代谢错误（IEM）的替代疗法。更具体地说，研究人员将把精力集中在苯丙氨酸羟化酶（PAH）缺陷的 Pahenu2 小鼠（一种人苯丙酮尿症（PKU）模型）上，并将评估肌肉中苯丙氨酸（Phe）代谢系统的表达，作为一种潜在的新型治疗方法。这种紊乱。对于许多 IEM 来说，疾病病理是由于循环有毒代谢物的影响，而不是酶缺乏造成的任何直接的组织特异性影响。例如，PAH主要在肝脏中表达，但与PKU相关的病理完全是由于循环Phe的影响；肝脏本身不受 PAH 缺乏的影响。任何实现血液 Phe 永久减少的治疗都将有效改善 PKU 表型。研究人员假设，骨骼肌中强大的 Phe 代谢系统的表达将增强肌肉中正常合成代谢 Phe 的摄取，有效代谢循环 Phe 并纠正高苯丙氨酸血症。他们将探索两种不同的 Phe 代谢系统：PAH 与 GTP 环化水解酶 1 (GTPCH) 和 6-丙酮酰四氢蝶呤合酶 (PTPS)（四氢生物蝶呤 (BH4) 合成途径的两个元件）在肌肉中协调表达，以提供 BH4支持 Phe 羟基化或苯丙氨酸解氨酶 (PAL) 表达所必需的辅助因子，不需要任何外部辅因子的苯丙氨酸代谢酶。在具体目标 1 中，研究人员将采用标准种系修饰方法来开发在所有骨骼肌中表达 Phe 代谢系统的转基因小鼠。这些小鼠将与 Pahenu2 小鼠交配，产生缺乏肝脏 PAH 活性但在肌肉中表达 Phe 代谢系统的后代。将在这些后代中评估 Phe 清除率。在具体目标 2 中，他们将分别采用重组腺相关病毒血清型 1 载体 (rAAV2/1) 或通过流体动力肢体静脉注射递送的裸质粒 DNA 载体，直接在 Pahenu2 小鼠后肢肌肉中诱导 Phe 代谢系统的表达。有人提出，PAH 与 BH4 合成途径的元件或单独的 PAL 的肌肉表达将导致 Pahenu2 小鼠的高苯丙氨酸血症得到纠正。公共健康相关性：该项目的总体目标是开发新的基因治疗方法，用于治疗出生时通过新生儿筛查检测到的遗传性代谢紊乱。研究人员将肌肉基因疗法描述为遗传性代谢性疾病的一种新治疗方法，并将特别关注人类苯丙酮尿症（PKU）（最常见的代谢性疾病之一）的小鼠模型。