Streptozotocin-induced β-cell death is independent of its inhibition of O-GlcNAcase in pancreatic Min6 cells
Streptozotocin-induced β-cell death is independent of its inhibition of O-GlcNAcase in pancreatic Min6 cells
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DOI：
10.1006/abbi.2000.2094
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发表时间：
2000-11-15
影响因子：
3.9
通讯作者：
Hart, GW
中科院分区：
文献类型：
--
作者：
Gao, Y;Parker, GJ;Hart, GW
向实验动物注射链脲佐菌素(STZ)选择性地导致大量的β细胞死亡。这种特定毒性的机制还不完全清楚。最近，人们发现O-连接的N-乙酰氨基葡萄糖(O-GlcNAc)富含在β细胞中，有人提出STZ的毒性可能是由于它抑制中性O-GlcNAcase的活性，O-GlcNAc是从胞浆蛋白中去除O-GlcNAc的酶(K，Liu ct al，2000，Proc)。纳特·阿卡德。SCI。美国97,2820-2825)，为了进一步确定O-GlcNA-Case在β细胞死亡中的作用，我们在胰腺Min6细胞中使用了一种有效和特异的O-GlcNAcase抑制剂PUGNAc和STZ。STZ和PUGNAc对细胞内蛋白的O-GlcNAc水平均升高至相似水平。STZ在8h内使细胞蛋白质合成减少66.0%，在18h内杀死80.9%的细胞，并减少胰岛素的分泌。STZ，而不是PUGNAc，也引起了基因组DNA的断裂，这表明一些细胞正在经历凋亡。延长PUGNAc处理时间(72 H)可维持较高的细胞内O-GlcNAc水平，但不会造成明显的细胞损伤。此外，STZ的毒性可以被聚腺苷二磷酸核糖聚合酶抑制剂3-氨基苯甲酰胺很大程度上逆转。这些数据有力地表明，STZ诱导的β细胞死亡不是由细胞内O-GlcNAc水平升高引起的，而是可能与多聚(ADP-核糖)聚合酶有关。(C)2000年学术出版社。
Streptozotocin (STZ) injection into experimental animals selectively causes massive beta -cell death. The mechanism of this specific toxicity is not fully understood. Recently, it has been discovered that O-linked N-acetylglucosamine (O-GlcNAc) is enriched in the beta -cells, it has been proposed that STZ toxicity may be due to its inhibition of neutral O-GlcNAcase activity, the enzyme that removes O-GlcNAc from cytosolic proteins (K, Liu ct al., 2000, Proc. Natl Acad. Sci. USA 97, 2820-2825), To further ascertain the role of O-GlcNA-case in beta -cell death, we have used PUGNAc, a potent and specific O-GlcNAcase inhibitor, together with STZ in pancreatic Min6 cells. Both STZ and PUGNAc increased O-GlcNAc to similar levels on intracellular proteins. STZ, but not PUGNAc, decreased cellular protein synthesis by 66.0% within 8 h, killed 80.9% of the cells within 18 h, and decreased insulin secretion. STZ, but not PUGNAc, also caused genomic DNA fragmentation, suggesting that some of the cells were undergoing apoptosis. Prolonged treatment with PUGNAc (72 h) maintained high intracellular O-GlcNAc levels, but did not result in any apparent cell damage. Furthermore, the toxicity of STZ can be largely reversed by 3-aminobenzamide, a poly(ADP-ribose) polymerase inhibitor. These data strongly indicate that STZ-induced beta -cell death is not caused by elevated intracellular O-GlcNAc levels, but instead likely involves poly(ADP-ribose) polymerase in the mechanism. (C) 2000 Academic Press.