Altered lipid content inhibits autophagic vesicular fusion
Altered lipid content inhibits autophagic vesicular fusion
复制标题
DOI：
10.1096/fj.09-144519
复制
发表时间：
2010-08-01
期刊：
影响因子：
4.8
通讯作者：
Cuervo, Ana Maria
中科院分区：
文献类型：
--
作者：
Koga, Hiroshi;Kaushik, Susmita;Cuervo, Ana Maria
自噬/溶酶体系统包括各种囊泡室，经历动态融合事件。然而，调节这些相互作用的特征和因素在很大程度上仍然是未知的。为了深入了解控制溶酶体融合事件的特性，我们使用从小鼠肝脏分离的不同溶酶体/自噬室建立了体外融合实验。我们发现自噬体/溶酶体融合是一个温度依赖的过程（融合增量为0.2 +/- 0.01%/℃），需要ATP （1-3 mM）、GTP （1-2 mM）、Ca2+ (0.2-2 mM)和酸性溶酶体pH （pH 5.2）。此外，膜脂组成的变化，无论是在体外用25毫米甲基- β -环糊精处理，还是在体内用高脂肪饮食刺激动物（脂肪中卡路里含量为60%），都会使自噬体/溶酶体融合减少，其减少程度是未处理部分或正常饮食动物的70%。这些发现揭示了脂质在自噬融合中的新作用，并为暴露于慢性脂质挑战时观察到的大自噬率降低提供了机制。因此，细胞内脂质含量的变化（即代谢紊乱）可能对巨噬的融合步骤产生显著影响，并影响细胞内蛋白水解途径的整体活性。-Koga， H, Kaushik， S, Cuervo， A. M.脂质含量改变抑制自噬泡融合。中国生物医学工程学报，2009,32(4):559 - 564（2010）。www.fasebj.org
The autophagic/lysosomal system includes a variety of vesicular compartments that undergo dynamic fusion events. However, the characteristics and factors modulating these interactions remain, for the most part, unknown. To gain insights on the properties that govern lysosomal fusion events, we have established an in vitro fusion assay using different lysosomal/autophagic compartments isolated from mouse liver. We have found that autophagosome/lysosome fusion is a temperaturedependent process (fusion increment of 0.2 +/- 0.01%/degrees C), which requires ATP (1-3 mM), GTP (1-2 mM), Ca2+ (0.2-2 mM), and an acidic lysosomal pH (pH 5.2). Furthermore, changes in membrane lipid composition, induced either in vitro, by treatment with 25 mM methyl-beta-cyclodextrin, or in vivo, by subjecting animals to a high-fat-diet challenge (60% kcal in fat) reduce autophagosome/lysosome fusion up to 70% of that observed in untreated fractions or from animals under a normal regular diet. These findings reveal a novel role for lipids in autophagic fusion and provide a mechanism for the reduced macroautophagic rates observed during exposure to a chronic lipid challenge. Changes in the intracellular lipid content (i.e., metabolic disorders) may thus have pronounced effects on the fusion step of macroautophagy and affect the overall activity of this intracellular proteolytic pathway.-Koga, H., Kaushik, S., Cuervo, A. M. Altered lipid content inhibits autophagic vesicular fusion. FASEB J. 24, 3052-3065 (2010). www.fasebj.org