title: GLUT3 and PKM2 regulate OCT4 expression and support the hypoxic culture of human embryonic stem cells.
abstract: Human embryonic stem cells (hESCs) have the capacity to differentiate into all cell types and thus have great potential for regenerative medicine. hESCs cultured at low oxygen tensions are more pluripotent and display an increased glycolytic rate but how this is regulated is unknown. This study therefore aimed to investigate the regulation of glucose metabolism in hESCs and whether this might impact OCT4 expression. In contrast to the glucose transporter GLUT1, GLUT3 was regulated by environmental oxygen and localised to hESC membranes. Silencing GLUT3 caused a reduction in glucose uptake and lactate production as well as OCT4 expression. GLUT3 and OCT4 expression were correlated suggesting that hESC self-renewal is regulated by the rate of glucose uptake. Surprisingly, PKM2, a rate limiting enzyme of glycolysis displayed a nuclear localisation in hESCs and silencing PKM2 did not alter glucose metabolism suggesting a role other than as a glycolytic enzyme. PKM2 expression was increased in hESCs cultured at 5% oxygen compared to 20% oxygen and silencing PKM2 reduced OCT4 expression highlighting a transcriptional role for PKM2 in hESCs. Together, these data demonstrate two separate mechanisms by which genes regulating glucose uptake and metabolism are involved in the hypoxic support of pluripotency in hESCs.
authors.affiliation: Centre for Human Development, Stem Cells &Regeneration, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK.|Human Development and Health Academic Unit, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK.
authors.forename: David R
authors.initials: DR
authors.lastname: Christensen
authors.affiliation: Human Development and Health Academic Unit, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK.|NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK.
authors.forename: Philip C
authors.initials: PC
authors.lastname: Calder
authors.affiliation: Centre for Human Development, Stem Cells &Regeneration, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK.|Human Development and Health Academic Unit, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK.
authors.forename: Franchesca D
authors.initials: FD
authors.lastname: Houghton
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism*; D015687:Cell Hypoxia / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D020868:Gene Silencing / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D051272:Glucose Transporter Type 1 / Q000378:metabolism; D051274:Glucose Transporter Type 3 / Q000378:metabolism*; D000066449:Human Embryonic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D050814:Octamer Transcription Factor-3 / Q000235:genetics* / Q000378:metabolism; D010100:Oxygen / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects; D013963:Thyroid Hormones / Q000378:metabolism*; D000097810:Thyroid Hormone-Binding Proteins
chemical_list: D002352:Carrier Proteins; D005947:Glucose; D051272:Glucose Transporter Type 1; D051274:Glucose Transporter Type 3; D019344:Lactic Acid; D008565:Membrane Proteins; D050814:Octamer Transcription Factor-3; D010100:Oxygen; D013963:Thyroid Hormones; D000097810:Thyroid Hormone-Binding Proteins; C494173:POU5F1 protein, human; C495677:SLC2A1 protein, human; C495687:SLC2A3 protein, human