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

描述(由申请人提供)： 粘多糖症(MRS)是一类广泛的遗传性疾病，其特征是糖胺聚糖(GAG)在各种组织的溶酶体中过度积聚。在这些疾病中，MPS I-H是最严重的常染色体隐性遗传性溶酶体储存病，由IDUA基因编码的α-L艾杜糖苷酶缺乏引起，该酶参与溶酶体内GAG的降解。最近的研究表明，某些氨基糖苷类药物和其他药理制剂有能力抑制导致一系列遗传病的STOP突变[参见Keling和Bedwell，当代药物基因组学3：259-269，(2005)]。与以前的结果一致，我们发现氨基糖苷庆大霉素可以抑制IDUA Q70X和W402X过早停止突变(约70%的MPS I-H患者携带)，并恢复足够的a-L艾杜糖酸酶活性以使MPS I-H患者来源的培养的原代成纤维细胞GAG水平正常化[基林等，人类分子遗传学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/c/tya-W402X敲入小鼠，将在MPS I-H患者中发现的/DLW-W402X过早停止突变引入到小鼠IDUA基因的相应位置。这一新的小鼠模型将使我们能够检验这样的假设，即抑制过早停止突变和/或无意义介导的信使核糖核酸衰变可以恢复足够的a-L艾杜糖酸酶活性，以纠正MPS I-H在体内的疾病表现。为了验证这一假设，并进一步开发和评估这一治疗策略的实用性，我们提出了以下特定目标：特定目标#1：鉴定与纯合子/dt/a-W402X小鼠相关的表型。具体目标#2：确定抑制过早停止突变的化合物是否可以在纯合子LDUA-N4Q2X小鼠中恢复显著的a-L艾杜糖苷酶活性。具体目标#3：研究NMD与抑制/DUA-W402X突变之间的关系。

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.