Up‐regulation of the pentose phosphate pathway and HIF‐1α expression during neural progenitor cell induction following glutamate treatment in rat ex vivo retina
Up‐regulation of the pentose phosphate pathway and HIF‐1α expression during neural progenitor cell induction following glutamate treatment in rat ex vivo retina
复制标题
大鼠离体视网膜谷氨酸处理后神经祖细胞诱导过程中戊糖磷酸途径和 HIF-1α 表达的上调
DOI：
10.1002/cbin.11212
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发表时间：
2019
影响因子：
3.9
通讯作者：
Kimura Kazuhiro
中科院分区：
文献类型：
--
作者：
Tokuda Kazuhiro;Baron Byron;Yamashiro Chiemi;Kuramitsu Yasuhiro;Kitagawa Takao;Kobayashi Masaaki;Sonoda Koh‐Hei;Kimura Kazuhiro
代谢状态影响神经干/祖细胞的调节。磷酸戊糖途径（PPP）是一种与糖酵解平行运作的替代代谢途径，不仅为生物合成反应提供关键中间体，而且还控制神经干/祖细胞的命运。我们以前已经表明，谷氨酸的应用导致诱导的神经祖细胞在成熟的离体大鼠视网膜。在这项研究中，我们调查了谷氨酸治疗视网膜后PPP的调节是否会改变。免疫印迹分析显示，葡萄糖-6-磷酸脱氢酶（G6 PD）（PPP的限速酶）以及6-磷酸葡萄糖酸脱氢酶（6PGD）（该途径中的另一种酶）的量在谷氨酸处理的视网膜中增加。与这两种酶产生还原的烟酰胺腺嘌呤二核苷酸磷酸（NADPH）的事实一致，与未处理的视网膜相比，处理的视网膜中的NAPDH的量显著更高。我们还发现，在谷氨酸处理的视网膜中，DNA合成以及脂肪酸合成酶（FATCH）的表达均显著增加。此外，缺氧诱导因子1-α（HIF-1α），PPP酶的正转录调节因子，在信使RNA（mRNA）和蛋白质水平上均上调。最后，我们发现了HIF-1α与丙酮酸激酶（PKM 2）的M2同工酶的相互作用，这种相互作用已被证明有助于糖酵解控制中的正反馈回路。因此，我们的研究结果表明，特定的PPP代谢变化发生在神经前体细胞诱导的过程中，在成熟的大鼠视网膜。
The metabolic state influences the regulation of neural stem/progenitor cells. The pentose phosphate pathway (PPP), an alternative metabolic pathway that operates parallel to glycolysis, not only provides key intermediates for biosynthetic reactions but also controls the fate of neural stem/progenitor cells. We have previously shown that glutamate application leads to the induction of neural progenitor cells in mature ex vivo rat retina. In this study, we investigated whether regulation of the PPP might be changed following glutamate treatment of the retina. Immunoblot analysis revealed that the amount of glucose‐6‐phosphate dehydrogenase (G6PD), the rate‐limiting enzyme of the PPP as well as that of 6‐phosphogluconate dehydrogenase (6PGD), another enzyme in this pathway, increased in the glutamate‐treated retina. Consistent with the fact that both these enzymes generate reduced nicotinamide adenine dinucleotide phosphate (NADPH), the amount of NAPDH in the treated retina was significantly higher compared with that in the untreated retina. We also found that both DNA synthesis as well as the expression of fatty acid synthase (FASN) increased significantly in the glutamate‐treated retina. Furthermore, hypoxia‐inducible factor 1‐α (HIF‐1α), a positive transcriptional regulator of PPP enzymes, was up‐regulated at both messenger RNA (mRNA) and protein levels. Finally, we found the interaction of HIF‐1α with the M2 isozyme of pyruvate kinase (PKM2), with this interaction having been shown to contribute to a positive feedback loop in the control of glycolysis. Our results thus show that specific metabolic change in the PPP occurs in the process of neural progenitor cell induction in the mature rat retina.