Park Hyoung Sook, Kim Ji Hye, Sun Bo Kyung, Song Sun U, Suh Wonhee, Sung Jong-Hyuk
Department of Pharmaceutics and Institute of Pharmaceutical Science, College of Pharmacy, Yonsei University, Incheon 21983, Republic of Korea.
Translational Research Center, Inha University School of Medicine, Incheon 22332, Republic of Korea.
Mol Med Rep. 2016 Nov;14(5):4706-4714. doi: 10.3892/mmr.2016.5796. Epub 2016 Oct 5.
It has previously been demonstrated that hypoxia has diverse stimulatory effects on adipose‑derived stem cells (ASCs), however, metabolic responses under hypoxia remain to be elucidated. Thus, the present study aimed to investigate the glucose uptake and metabolism of ASCs under hypoxic conditions, and to identify the underlying molecular mechanisms. ASCs were cultured in 1% oxygen, and experiments were conducted in vitro. As determined by proteomic analysis and western blotting, GAPDH and enolase 1 (ENO1) expression were upregulated under hypoxia. In addition, lactate production was significantly increased, and mRNA levels of glycolytic enzymes, including GAPDH, ENO1, hexokinase 2 (HK2), and lactate dehydrogenase α (LDHα) were upregulated. Hypoxia‑inducible factor 1‑α (HIF‑1α) expression was increased as demonstrated by western blotting, and a pharmacological inhibitor of HIF‑1α significantly attenuated hypoxia‑induced lactate production and expression of glycolytic enzymes. It was also observed that hypoxia significantly increased glucose uptake in ASCs, and glucose transporter (GLUT)1 and GLUT3 expression were upregulated under hypoxia. Pharmacological inhibition of the HIF‑1α signaling pathways also attenuated hypoxia‑induced GLUT1 and GLUT3 expression. These results collectively indicate that hypoxia increases glucose uptake via GLUT1 and GLUT3 upregulation, and induces lactate production of ASCs via GAPDH, ENO1, HK2, and LDHα. Furthermore, HIF‑1α is involved in glucose uptake and metabolism of ASCs.
此前已有研究表明，缺氧对脂肪来源干细胞（ASC）具有多种刺激作用，然而，缺氧条件下的代谢反应仍有待阐明。因此，本研究旨在探究缺氧条件下ASC的葡萄糖摄取和代谢情况，并确定其潜在的分子机制。将ASC在1%氧气条件下培养，并进行体外实验。通过蛋白质组学分析和蛋白质印迹法测定，缺氧条件下甘油醛-3-磷酸脱氢酶（GAPDH）和烯醇化酶1（ENO1）的表达上调。此外，乳酸生成显著增加，包括GAPDH、ENO1、己糖激酶2（HK2）和乳酸脱氢酶α（LDHα）在内的糖酵解酶的mRNA水平上调。蛋白质印迹法显示缺氧诱导因子1-α（HIF-1α）表达增加，HIF-1α的药理学抑制剂显著减弱了缺氧诱导的乳酸生成和糖酵解酶的表达。还观察到缺氧显著增加了ASC的葡萄糖摄取，缺氧条件下葡萄糖转运蛋白（GLUT）1和GLUT3的表达上调。HIF-1α信号通路的药理学抑制也减弱了缺氧诱导的GLUT1和GLUT3表达。这些结果共同表明，缺氧通过上调GLUT1和GLUT3增加葡萄糖摄取，并通过GAPDH、ENO1、HK2和LDHα诱导ASC产生乳酸。此外，HIF-1α参与了ASC的葡萄糖摄取和代谢。
