Metallothionein-3 Regulates Lysosomal Function in Cultured Astrocytes Under Both Normal and Oxidative Conditions
Metallothionein-3 Regulates Lysosomal Function in Cultured Astrocytes Under Both Normal and Oxidative Conditions
复制标题
DOI：
10.1002/glia.20998
复制
发表时间：
2010-08-01
期刊：
影响因子：
6.2
通讯作者：
Koh, Jae-Young
中科院分区：
文献类型：
--
作者：
Lee, Sook-Jeong;Park, Mi-Ha;Koh, Jae-Young
细胞锌在氧化应激下神经元和星形胶质细胞的溶酶体变化和细胞死亡中起关键作用。在这里，使用缺乏金属硫蛋白-3（MT3）的星形胶质细胞，一种大脑中不稳定锌的潜在来源，我们研究了MT3在氧化应激反应中的作用。H2 O2诱导野生型（WT）星形胶质细胞中不稳定锌的大量增加，但刺激MT3无效星形胶质细胞仅适度上升。此外，H2 O2诱导的溶酶体膜透化（LMP）和细胞死亡在MT3-null星形胶质细胞中被显著减弱。Lamp 1（溶酶体相关膜蛋白1）和Lamp 2的表达和糖基化在MT3缺失的星形胶质细胞中增加，并且几种溶酶体酶的活性显著降低，表明MT3对溶酶体组分的影响。与MT3-null细胞中的溶酶体功能障碍一致，LC 3-II（微管相关蛋白1轻链3）（早期自噬的标志物）的水平在WT星形胶质细胞中通过氧化应激增加，但在MT3-null细胞中没有。Lamp 1，LC 3和组织蛋白酶-D的类似变化诱导的溶酶体抑制剂巴弗洛霉素A1，氯喹，莫能菌素，表明溶酶体功能障碍可能位于上游的MT3-null星形胶质细胞中观察到的变化。与这一想法一致，胆固醇和脂褐质的溶酶体积累在MT3缺失的星形胶质细胞中增加。与MT3缺失细胞中观察到的结果相似，通过siRNA敲低MT3抑制了锌和LMP的氧化应激诱导的增加。这些结果表明，MT3可能在培养的星形胶质细胞的正常溶酶体功能中发挥关键作用。(C)2010年威利-利斯。Inc.
Cellular zinc plays a key role in lysosomal change and cell death in neurons and astrocytes under oxidative stress. Here, using astrocytes lacking metallothionein-3 (MT3), a potential source of labile zinc in the brain, we studied the role of MT3 in oxidative stress responses. H2O2 induced a large increase in labile zinc in wild-type (WT) astrocytes, but stimulated only a modest rise in MT3-null astrocytes. In addition, H2O2-induced lysosomal membrane permeabilization (LMP) and cell death were comparably attenuated in MT3-null astrocytes. Expression and glycosylation of Lamp1 (lysosome-associated membrane protein 1) and Lamp2 were increased in MT3-null astrocytes, and the activities of several lysosomal enzymes were significantly reduced, indicating an effect of MT3 on lysosomal components. Consistent with lysosomal dysfunction in MT3-null cells, the level of LC3-II (microtubule-associated protein 1 light chain 3), a marker of early autophagy, was increased by oxidative stress in WT astrocytes, but not in MT3-null cells. Similar changes in Lamp1, LC3, and cathepsin-D were induced by the lysosomal inhibitors bafilomycin A1, chloroquine, and monensin, indicating that lysosomal dysfunction may lie upstream of changes observed in MT3-null astrocytes. Consistent with this idea, lysosomal accumulation of cholesterol and lipofuscin were augmented in MT3-null astrocytes. Similar to the results seen in MT3-null cells, MT3 knockdown by siRNA inhibited oxidative stress-induced increases in zinc and LMP. These results indicate that MT3 may play a key role in normal lysosomal function in cultured astrocytes. (C) 2010 Wiley-Liss. Inc.