Glutamine enhances heat shock protein 70 expression via increased hexosamine biosynthetic pathway activity
Glutamine enhances heat shock protein 70 expression via increased hexosamine biosynthetic pathway activity
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DOI：
10.1152/ajpcell.00240.2009
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发表时间：
2009-12-01
影响因子：
5.5
通讯作者：
Wischmeyer, Paul E.
中科院分区：
文献类型：
--
作者：
Hamiel, Christine R.;Pinto, Shanti;Wischmeyer, Paul E.
哈米尔CR，平托S，Hau A，Wischmeyer PE.谷氨酰胺通过增加己糖胺生物合成途径活性增强热休克蛋白70表达。美国生理学杂志细胞生理学297：C1509-C1519，2009年。首次发表于2009年9月23日; doi：10.1152/ajpcell.00240.2009。谷氨酰胺（GLN）通过增强热休克蛋白70（HSP70）在损伤后的细胞保护中起关键作用。GLN增强HSP 70的途径尚不清楚。GLN是己糖胺生物合成途径（HBP）的关键底物，已显示其诱导HSP 70。我们试图探索HBP在GLN介导的HSP70表达中的作用。在小鼠胚胎成纤维细胞中使用化学抑制剂和关键HBP酶的小干扰（si）RNA敲低来确定HBP对HSP70表达的影响。O-糖基化，核转位，热休克因子-1（HSF-1）和Sp1的转录激活进行了评估，使用免疫沉淀，蛋白质印迹和荧光素酶测定。HSP70表达水平通过ELISA和Western blotting评估。GLN在热应激（HS）前后增强HBP活性。HBP酶的化学抑制降低GLN介导的HSP70表达。HBP关键酶UDP-N-乙酰葡糖胺（GlcNAc）的特异性siRNA靶向：多肽-O-β-乙酰葡糖胺转移酶（OGT）阻断GLN介导的HSP70表达，并减弱GLN介导的HS后细胞保护作用。HBP的化学和siRNA衰减阻断了GLN诱导的Sp1和HSF-1的核转位，这是最大HSP70表达的关键。最后，免疫沉淀显示HSF-1是O-糖基化的，GLN增强了这种作用。这些结果表明，通过HBP代谢GLN增强HSP 70表达。这种作用似乎是通过O-糖基化，核转位，转录激活Sp1和HSF-1介导的。这是一个重要的机制描述的途径，似乎负责GLN介导的HSP70的表达。
Hamiel CR, Pinto S, Hau A, Wischmeyer PE. Glutamine enhances heat shock protein 70 expression via increased hexosamine biosynthetic pathway activity. Am J Physiol Cell Physiol 297: C1509-C1519, 2009. First published September 23, 2009; doi:10.1152/ajpcell.00240.2009.-Glutamine (GLN) plays a key role in cellular protection following injury via enhancement of heat shock protein 70 (HSP70). The pathway by which GLN enhances HSP70 is unknown. GLN is a key substrate for the hexosamine biosynthetic pathway (HBP), which has been shown to induce HSP70. We sought to explore the role of the HBP in GLN-mediated HSP70 expression. Both chemical inhibitors and small interfering (si) RNA knockdown of key HBP enzymes were used in mouse embryonic fibroblast cells to determine the effects of the HBP on HSP70 expression. The O-glycosylation, nuclear translocation, and transcriptional activation of heat shock factor-1 (HSF-1) and Sp1 were evaluated using immunoprecipitation, Western blotting, and luciferase assays. HSP70 expression levels were evaluated via ELISA and Western blotting. GLN augmented HBP activity before and after heat stress (HS). Chemical inhibition of HBP enzymes reduced GLN-mediated HSP70 expression. Specific siRNA targeting of the key HBP enzyme UDP-N-acetylglucosamine (GlcNAc): polypeptide-O-beta-acetylglucosaminyltransferase (OGT) blocked GLN-mediated HSP70 expression and attenuated GLN-mediated cellular protection post-HS. Chemical and siRNA attenuation of the HBP blocked GLN-induced nuclear translocation of Sp1 and HSF-1, which are key to maximal HSP70 expression. Finally, immunoprecipitation revealed HSF-1 was O-glycosylated, and GLN enhanced this effect. These results suggest that metabolism of GLN via the HBP enhances HSP70 expression. This effect appears to be mediated via O-glycosylation, nuclear translocation, and transcriptional activation of Sp1 and HSF-1. This is an important mechanistic description of a pathway that appears responsible for GLN-mediated HSP70 expression.