Dysfunction of endocytic and autophagic pathways in a lysosomal storage disease
Dysfunction of endocytic and autophagic pathways in a lysosomal storage disease
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DOI：
10.1002/ana.20807
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发表时间：
2006-04-01
影响因子：
11.2
通讯作者：
Raben, N
中科院分区：
文献类型：
--
作者：
Fukuda, T;Ewan, L;Raben, N
目的了解Pompe病骨骼肌破坏和酶替代治疗抵抗的机制。Pompe病是一种溶酶体酸性α-葡萄糖苷酶(GAA)缺乏，糖原主要积聚在溶酶体中，主要分布在心肌和骨骼肌。方法：我们分析了GAA缺陷的成肌细胞和从野生型、未经处理和酶替代治疗的GAA基因敲除小鼠分离的单一I型和11型肌纤维中溶酶体降解途径的区段。结果。对GAA基因敲除小鼠成肌细胞的研究表明，内吞/自噬途径的囊泡急剧膨胀，过度拥挤的细胞中的囊泡运动减少，晚期内小体/溶酶体的子集存在酸化缺陷。通过共聚焦显微镜对分离的肌肉纤维的分析表明，在I型和II型肌纤维中，溶酶体糖原积累的后果是显著不同的。只有对治疗最具抵抗力的II型纤维含有跨越整个纤维长度的大片自噬积聚。解释：大量增加的自噬堆积可能是骨骼肌损伤的原因，并阻止替代酶向溶酶体的有效运输。
Objective To understand the mechanisms of skeletal muscle destruction and resistance to enzyme replacement therapy in Pompe disease, a deficiency of lysosomal acid a-glucosidase (GAA), in which glycogen accumulates in lysosomes primarily in cardiac and skeletal muscles. Methods: We have analyzed compartments of the lysosomal degradative pathway in GAA-deficient myoblasts and single type I and type 11 muscle fibers isolated from wild-type, untreated, and enzyme replacement therapy-treated GAA knock-out mice. Results. Studies in myoblasts from GAA knock-out mice showed a dramatic expansion of vesicles of the endocytic/autophagic pathways, decreased vesicular movement in overcrowded cells, and an acidification defect in a subset of late endosomes/lysosomes. Analysis by confocal microscopy of isolated muscle fibers demonstrated that the consequences of the lysosomal glycogen accumulation are strikingly different in type I and II muscle fibers. Only type II fibers, which are the most resistant to therapy, contain large regions of autophagic buildup that span the entire length of the fibers. Interpretation The vastly increased autophagic buildup may be responsible for skeletal muscle damage and prevent efficient trafficking of replacement enzyme to lysosomes.