Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy.
Mol Ther. 2012 Dec;20(12):2201-11. doi: 10.1038/mt.2012.152. Epub 2012 Sep 18.
Pompe disease (PD) is a metabolic myopathy due to the deficiency of the lysosomal enzyme α-glucosidase (GAA). The only approved treatment for this disorder, enzyme replacement with recombinant human GAA (rhGAA), has shown limited therapeutic efficacy in some PD patients. Pharmacological chaperone therapy (PCT), either alone or in combination with enzyme replacement, has been proposed as an alternative therapeutic strategy. However, the chaperones identified so far also are active site-directed molecules and potential inhibitors of target enzymes. We demonstrated that N-acetylcysteine (NAC) is a novel allosteric chaperone for GAA. NAC improved the stability of rhGAA as a function of pH and temperature without disrupting its catalytic activity. A computational analysis of NAC-GAA interactions confirmed that NAC does not interact with GAA catalytic domain. NAC enhanced the residual activity of mutated GAA in cultured PD fibroblasts and in COS7 cells overexpressing mutated GAA. NAC also enhanced rhGAA efficacy in PD fibroblasts. In cells incubated with NAC and rhGAA, GAA activities were 3.7-8.7-fold higher than those obtained in cells treated with rhGAA alone. In a PD mouse model the combination of NAC and rhGAA resulted in better correction of enzyme activity in liver, heart, diaphragm and gastrocnemia, compared to rhGAA alone.
庞贝病（PD）是一种由于溶酶体酶α-葡萄糖苷酶（GAA）缺乏引起的代谢性肌病。目前唯一被批准用于治疗这种疾病的方法是用重组人 GAA（rhGAA）进行酶替代治疗，但在一些 PD 患者中，该方法的治疗效果有限。单独使用或与酶替代治疗联合使用的药理学伴侣治疗（PCT）已被提议作为一种替代治疗策略。然而，迄今为止鉴定的伴侣也是活性位点定向分子，并且是靶酶的潜在抑制剂。我们证明 N-乙酰半胱氨酸（NAC）是 GAA 的一种新型别构伴侣。NAC 提高了 rhGAA 的稳定性，这是 pH 和温度的函数，而不会破坏其催化活性。对 NAC-GAA 相互作用的计算分析证实，NAC 不与 GAA 催化结构域相互作用。NAC 增强了培养的 PD 成纤维细胞和过表达突变 GAA 的 COS7 细胞中突变 GAA 的残余活性。NAC 还增强了 rhGAA 在 PD 成纤维细胞中的疗效。在用 NAC 和 rhGAA 孵育的细胞中，GAA 活性比单独用 rhGAA 处理的细胞高 3.7-8.7 倍。在 PD 小鼠模型中，与单独使用 rhGAA 相比，NAC 和 rhGAA 的组合导致肝脏、心脏、膈肌和腓肠肌中的酶活性得到更好的纠正。
