title: Differential regulation of GLUT1 activity in human corneal limbal epithelial cells and fibroblasts.
abstract: The corneal epithelial tissue is a layer of rapidly growing cells that are highly glycolytic and express GLUT1 as the major glucose transporter. It has been shown that GLUT1 in L929 fibroblast cells and other cell lines can be acutely activated by a variety agents. However, the acute regulation of glucose uptake in corneal cells has not been systematically investigated. Therefore, we examined glucose uptake in an immortalized human corneal-limbal epithelial (HCLE) cell line and compared it to glucose uptake in L929 fibroblast cells, a cell line where glucose uptake has been well characterized. We report that the expression of GLUT1 in HCLE cells is 6.6-fold higher than in L929 fibroblast cells, but the HCLE cells have a 25-fold higher basal rate of glucose uptake. Treatment with agents that interfere with mitochondrial metabolism, such as sodium azide and berberine, activate glucose uptake in L929 cells over 3-fold, but have no effect on glucose uptake HCLE cells. Also, agents known to react with thiols, such cinnamaldehyde, phenylarsine oxide and nitroxyl stimulate glucose uptake in L929 cells 3-4-fold, but actually inhibit glucose uptake in HCLE cells. These data suggest that in the fast growing HCLE cells, GLUT1 is expressed at a higher concentration and is already highly activated at basal conditions. These data support a model for the acute activation of GLUT1 that suggests that the activity of GLUT1 is enhanced by the formation of an internal disulfide bond within GLUT1 itself.
authors.affiliation: Department of Chemistry and Biochemistry, Calvin College, 3201 Burton SE, Grand Rapids, MI 49546, USA.
authors.forename: David P
authors.initials: DP
authors.lastname: Kuipers
authors.forename: Jared P
authors.initials: JP
authors.lastname: Scripture
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Gunnink
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Salie
authors.forename: Mark P
authors.initials: MP
authors.lastname: Schotanus
authors.forename: John L
authors.initials: JL
authors.lastname: Ubels
authors.forename: Larry L
authors.initials: LL
authors.lastname: Louters
mesh_terms: D000171:Acrolein / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001152:Arsenicals / Q000494:pharmacology; D001599:Berberine / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002460:Cell Line; D004220:Disulfides / Q000737:chemistry; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D005947:Glucose / Q000378:metabolism*; D051272:Glucose Transporter Type 1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D016850:Limbus Corneae / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D009589:Nitrogen Oxides / Q000494:pharmacology; D009928:Organ Specificity; D019810:Sodium Azide / Q000494:pharmacology
chemical_list: D001152:Arsenicals; D004220:Disulfides; D051272:Glucose Transporter Type 1; D009589:Nitrogen Oxides; C495677:SLC2A1 protein, human; C495678:Slc2a1 protein, mouse; C029341:oxophenylarsine; D001599:Berberine; D000171:Acrolein; D019810:Sodium Azide; C039900:nitroxyl; D005947:Glucose; C012843:cinnamaldehyde