Abnormal mannose-6-phosphate receptor trafficking impairs recombinant alpha-glucosidase uptake in Pompe disease fibroblasts.
Abnormal mannose-6-phosphate receptor trafficking impairs recombinant alpha-glucosidase uptake in Pompe disease fibroblasts.
复制标题
DOI：
10.1186/1755-8417-1-6
复制
发表时间：
2008-12-01
期刊：
影响因子：
--
通讯作者：
Parenti, Giancarlo
中科院分区：
文献类型：
--
作者：
Cardone, Monica;Porto, Caterina;Parenti, Giancarlo
背景：庞贝氏症（PD）是一种由α-葡萄糖苷酶（GAA）缺乏引起的代谢性肌病，以全身性糖原累积为特征。异质性GAA基因突变导致广泛的表型变异，从严重的经典婴儿表现到较温和的中间和晚发型形式。酶替代疗法（ERT）与重组人GAA（rhGAA），唯一的治疗方法可用于PD，有趣的是，不同的PD患者显示不同的疗效。为了研究ERT的可变反应的机制，我们研究了PD成纤维细胞的细胞形态，介导rhGAA摄取的阳离子非依赖性甘露糖-6-磷酸受体（CI-MPR）的分布和运输，以及rhGAA摄取本身。电子显微镜分析显示多泡体的积累和高尔基体的扩张，LC 3的免疫定位和蛋白质印迹分析显示自噬的激活。免疫荧光分析显示PD成纤维细胞中CI-MPR的细胞内分布异常，与LC 3的共定位增加，质膜上受体的可用性降低。CI-MPR从质膜到trans-Golgi网络的再循环也受损。所有这些异常在重度和中度PD成纤维细胞中更为突出，与疾病严重程度相关。在严重和中间PD细胞rhGAA的摄取和加工效率较低，纠正GAA活性reduced.CONCLUSION：这些结果表明，中断CI-MPR贩运的作用在可变的响应ERT在PD和ERT的疗效和优化的治疗方案的影响。
BACKGROUND: Pompe disease (PD) is a metabolic myopathy caused by alpha-glucosidase (GAA) deficiency and characterized by generalized glycogen storage. Heterogeneous GAA gene mutations result in wide phenotypic variability, ranging from the severe classic infantile presentation to the milder intermediate and late-onset forms. Enzyme replacement therapy (ERT) with recombinant human GAA (rhGAA), the only treatment available for PD, intriguingly shows variable efficacy in different PD patients. To investigate the mechanisms underlying the variable response to ERT, we studied cell morphology of PD fibroblasts, the distribution and trafficking of the cation-independent mannose-6-phosphate receptor (CI-MPR) that mediates rhGAA uptake, and rhGAA uptake itself.RESULTS: We observed abnormalities of cell morphology in PD cells. Electron microscopy analysis showed accumulation of multivesicular bodies and expansion of the Golgi apparatus, and immunolocalization and western blot analysis of LC3 showed activation of autophagy. Immunofluorescence analysis showed abnormal intracellular distribution of CI-MPR in PD fibroblasts, increased co-localization with LC3 and reduced availability of the receptor at the plasma membrane. The recycling of CI-MPR from the plasma membrane to the trans-Golgi network was also impaired. All these abnormalities were more prominent in severe and intermediate PD fibroblasts, correlating with disease severity. In severe and intermediate PD cells rhGAA uptake and processing were less efficient and correction of GAA activity was reduced.CONCLUSION: These results indicate a role for disrupted CI-MPR trafficking in the variable response to ERT in PD and have implications for ERT efficacy and optimization of treatment protocols.