Effect of hypoxia on 2-deoxyglucose uptake and cell cycle regulatory protein expression of mouse embryonic stem cells: involvement of Ca2+ /PKC, MAPKs and HIF-1alpha.
This study investigated the signal molecules linking the alteration in 2-dexoyglucose (2-DG) uptake and DNA synthesis in mouse embryonic stem (ES) cells under hypoxia. Hypoxia increased the 2-DG uptake and GLUT-1 protein expression level while the undifferentiated state of ES cells and cell viability were not affected by the hypoxia (1 - 48h). Subsequently, [(3)H] thymidine incorporation was significantly increased at 12 hours of hypoxic exposure. Hypoxia increased the Ca(2+) uptake and PKC beta (I), epsilon, and zeta translocation from the cytosol to the membrane fraction. Moreover, hypoxia increased the level of p44/42 mitogen-activated protein kinases (MAPKs) phosphorylation and hypoxia inducible factor-1alpha (HIF-1alpha) in a time-dependent manner. On the other hand, inhibition of these pathways blocked the hypoxia-induced increase in the 2-DG uptake and GLUT-1 protein expression level. Under hypoxia, cell cycle regulatory protein expression [cyclin D1, cyclin E, cyclin-dependent kinase (CDK) 2, and CDK 4] were increased in a time-dependent manner, which were blocked by PD 98059. pRB protein was also increased in a time-dependent manner. In conclusion, under hypoxia, there might be a parallel relationship between the expression of GLUT1 and DNA synthesis, which is mediated by the Ca(2+) /PKC, MAPK, and the HIF-1alpha signal pathways in mouse ES cells.
Lee
Sang Hun
SH
Department of Veterinary Physiology, Biotherapy Human Resources Center, College of Veterinary Medicine, Chonnam National University, Gwangju, Korea.
Heo
Jung Sun
JS
Han
Ho Jae
HJ
D000199:Actins; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D018929:Cell Culture Techniques; D004247:DNA / Q000096:biosynthesis; D003847:Deoxyglucose / Q000378:metabolism*; D053595:Embryonic Stem Cells; D004791:Enzyme Inhibitors; D005786:Gene Expression Regulation; D051272:Glucose Transporter Type 1 / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000037:antagonists & inhibitors / Q000378:metabolism; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*
D000199:Actins; D004791:Enzyme Inhibitors; D051272:Glucose Transporter Type 1; C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C495678:Slc2a1 protein, mouse; D004247:DNA; D003847:Deoxyglucose; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D002118:Calcium