Engineering a Supplemental Phenylalanine Metabolic Pathway to Prevent mPKU

设计补充苯丙氨酸代谢途径来预防 mPKU

• 批准号: 7898820
• 负责人: STEPHEN K. HUNTER
• 金额: $ 17.91万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7898820
• 关键词: Affect; Age; Brain; Cardiac; Cell Line; Cells; Characteristics; Child; Cognitive; Defect; Development; Diet; Encapsulated; Engineering; Enzymes; Face; Fertility; Fetus; Generations; Growth; Immune system; Individual; Intake; Lead; Life; Maternal Phenylketonuria; Mental Retardation; Metabolic; Metabolic Pathway; Microspheres; Morphology; Mus; Mutate; Neonatal Screening; Partner in relationship; Pathway interactions; Patients; Persons; Phenylalanine; Phenylalanine Hydroxylase; Pregnancy; Pregnant Women; Process; Psyche structure; Seizures; Staging; Syndrome; Taste Perception; Time; Woman; compliance behavior; dietary restriction; dietary supplements; fetal; genetically modified cells; implantation; inhibitor/antagonist; mouse model; prevent; pup

DESCRIPTION (provided by applicant): The Hunter lab proposes to develop genetically modified cells to overproduce Phenylalanine Hydroxylase (PAH). This enzyme is frequently mutated and completely or partially inactive in persons with phenylketonuria (PKU). Without this enzyme, high levels of phenylalanine and its metabolites build up and through an unknown pathway lead to profound and irreversible mental retardation, seizures, and reduced growth. The current therapy is nutritional supplements and dietary restriction limiting the intake of phenylalanine. Although difficult, this therapy is recommended for the life of the individual. While the combination of newborn screening and dietary therapy has been extremely successful in preventing severe mental retardation in PKU patients, several inadequacies exist. Some treated children still suffer mild cognitive defects. Main inhibitors of patient compliance include the foul taste, expense, and restrictiveness of the diet. Because the diet is very limited and distasteful, many pregnant women with PKU cannot tolerate it and consequently cannot control their phenylalanine levels. The consequence is termed maternal PKU syndrome. Maternal PKU syndrome has only emerged within the last 15-20 years as the first generation of women to receive dietary treatment as children reach child-bearing age. These women have normal fertility. However, prior to the dietary therapy, most PKU patients had profound cognitive problems and did not reproduce. In maternal PKU syndrome, the child does not necessarily suffer from the metabolic error. Instead, the maternal PKU has teratogenic effects on the fetus. Maternal PKU affects the fetal brain, growth, facial morphology, and cardiac development. The objective of this proposal is to develop and evaluate cell lines for their ability to over-express PAH and to process phenylalanine. These cells will then be encapsulated within polymeric microspheres. The microspheres isolate these cells from the immune system. Encapsulated cells will be injected intraperitoneally into PKU model mice. Mice will be evaluated for changes in their ability to metabolize phenylalanine before and after implantation. In addition, mice will be mated and the physical and mental characteristics of the pups will be evaluated. Furthermore, mice will be injected at different time points during pregnancy to evaluate the effects of "boosting" the phenylalanine metabolic pathway with the encapsulated cells at different stages of pregnancy on the pups.

描述（由申请人提供）： 亨特实验室提议开发转基因细胞来过量生产苯丙氨酸羟化酶（PAH）。这种酶在苯丙酮尿症 (PKU) 患者中经常发生突变，并且完全或部分失活。如果没有这种酶，高水平的苯丙氨酸及其代谢物就会积聚，并通过未知的途径导致严重且不可逆转的智力迟钝、癫痫发作和生长迟缓。目前的治疗方法是营养补充剂和饮食限制，限制苯丙氨酸的摄入。尽管困难，但建议患者终生使用这种疗法。虽然新生儿筛查和饮食治疗相结合在预防 PKU 患者严重精神发育迟滞方面非常成功，但仍存在一些不足之处。一些接受治疗的儿童仍然存在轻度认知缺陷。影响患者依从性的主要因素包括难闻的味道、费用和饮食限制。由于饮食非常有限且令人厌恶，许多患有PKU的孕妇无法耐受，因此无法控制苯丙氨酸水平。其后果被称为母亲 PKU 综合征。 母亲 PKU 综合征是在过去 15-20 年内才出现的，是第一代在孩子达到育龄时接受饮食治疗的女性。这些妇女具有正常的生育能力。然而，在饮食治疗之前，大多数 PKU 患者都存在严重的认知问题，并且无法生育。患有 PKU 综合征的母亲，孩子不一定会出现代谢错误。相反，母体 PKU 对胎儿有致畸作用。 母体 PKU 会影响胎儿的大脑、生长、面部形态和心脏发育。 该提案的目的是开发和评估细胞系过度表达 PAH 和加工苯丙氨酸的能力。然后这些细胞将被封装在聚合物微球内。微球将这些细胞与免疫系统隔离。将封装的细胞腹膜内注射到 PKU 模型小鼠中。将评估小鼠在植入前后代谢苯丙氨酸的能力的变化。此外，还将对小鼠进行交配，并对幼崽的身体和心理特征进行评估。此外，将在小鼠怀孕期间的不同时间点进行注射，以评估封装细胞在怀孕不同阶段“促进”苯丙氨酸代谢途径对幼仔的影响。