title: 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.
abstract: 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.
authors.affiliation: Department of Veterinary Physiology, Biotherapy Human Resources Center, College of Veterinary Medicine, Chonnam National University, Gwangju, Korea.
authors.forename: Sang Hun
authors.initials: SH
authors.lastname: Lee
authors.forename: Jung Sun
authors.initials: JS
authors.lastname: Heo
authors.forename: Ho Jae
authors.initials: HJ
authors.lastname: Han
mesh_terms: 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*
chemical_list: 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