Suppression of the Idua-W402X mutation in an MPS I-H mouse

描述（由申请人提供）： 粘多糖沉积症（MRS）是一类广泛的遗传性疾病，其特征在于各种组织的溶酶体内糖胺聚糖（GAG）的过度积累。在这些疾病中，MPS I-H是由α-L-艾杜糖醛酸酶（由IDUA基因编码）缺乏引起的常染色体隐性溶酶体贮积病的最严重形式，其参与溶酶体内GAG的降解。最近的研究已经表明，某些氨基糖苷类和其它药理学试剂具有抑制引起许多遗传疾病的终止突变的能力[综述参见Keeling和Bedwell，Current Pharmacogenomics 3：259-269，（2005）]。与这些先前的结果一致，我们发现氨基糖苷类庆大霉素可以抑制IDUA Q70 X和W 402 X过早终止突变（由约70%的MPS I-H患者携带），并恢复足够的α-L-艾杜糖醛酸酶活性以使来自MPS I-H患者的培养的原代成纤维细胞中的GAG水平正常化[Keeling et al.，Human Molecular Genetics 10：291-299（2001）]。为了进一步探索这种新的治疗方法，我们最近成功地构建了一种/c/tya-W 402 X基因敲入小鼠，其中在MPS I-H患者中发现的/DLW-W 402 X过早终止突变被引入小鼠Idua基因的相应位置。这种新的小鼠模型将使我们能够测试以下假设：抑制过早终止突变和/或无义介导的mRNA衰减（NMD）可以恢复足够的α-L-艾杜糖醛酸酶活性，以纠正体内MPS I-H的疾病表现。为了检验这一假设并进一步开发和评估这种治疗策略的效用，我们提出了以下具体目标：具体目标#1：表征与纯合/dt/a-W 402 X小鼠相关的表型。具体目标#2：确定抑制过早终止突变的化合物是否可以在纯合Idua-1 N4 Q2 X小鼠中恢复显著的a-L-艾杜糖醛酸酶活性。具体目标#3：检查NMD和/dua-W 402 X突变抑制之间的关系。

DESCRIPTION (provided by applicant): The mucopolysaccharidosis (MRS) diseases are a broad class of genetic disorders characterized by the excessive accumulation of glycosaminoglycans (GAGs) within the lysosomes of various tissues. Among these disorders, MPS I-H is the most severe form of an autosomal recessive lysosomal storage disease caused by a deficiency of a-L-iduronidase (encoded by the IDUA gene), which participates in the degradation of GAGs within the lysosome. Recent studies have shown that certain aminoglycosides and other pharmacological agents have the ability to suppress stop mutations that cause a number of genetic diseases [For review, see Keeling and Bedwell, Current Pharmacogenomics 3: 259-269, (2005)]. Consistent with these previous results, we found that the aminoglycoside gentamicin can suppress the IDUA Q70X and W402X premature stop mutations (carried by ~70% of MPS I-H patients) and restore enough a-L-iduronidase activity to normalize GAG levels in cultured primary fibroblasts derived from an MPS I-H patient [Keeling et al., Human Molecular Genetics 10: 291-299 (2001)]. To further explore this novel therapeutic treatment, we recently succeeded in constructing an /c/tya-W402X knock-in mouse in which the /DLW-W402X premature stop mutation found in MPS I-H patients was introduced into the corresponding position in the mouse Idua gene. This new mouse model will allow us to test the hypothesis that the suppression of premature stop mutations and/or nonsense-mediated mRNA decay (NMD) can restore enough a-L-iduronidase activity to correct the disease manifestations of MPS I-H in vivo. To test this hypothesis and further develop and evaluate the utility of this treatment strategy, we propose the following specific aims: Specific Aim #1: Characterize the phenotype associated with a homozygous /dt/a-W402X mouse. Specific Aim #2: Determine whether compounds that suppress premature stop mutations can restore significant a-L-iduronidase activity in a homozygous ldua-\N4Q2X mouse. Specific Aim #3: Examine the relationship between NMD and suppression of the /dua-W402X mutation.