Title

Acute Modulation of Sugar Transport in Brain Capillary Endothelial Cell Cultures during Activation of the Metabolic Stress Pathway

Student Author(s)

Anthony J. Cura

GSBS Program

Biochemistry & Molecular Pharmacology

UMMS Affiliation

Department of Biochemistry and Molecular Pharmacology

Date

5-14-2010

Document Type

Article

Medical Subject Headings

Adenosine Triphosphate; Animals; Base Sequence; Brain; Capillaries; Carbohydrate Metabolism; Cell Line; Cytochalasin B; DNA Primers; Endothelium, Vascular; Mice; Oxidative Stress; Phosphorylation; Reverse Transcriptase Polymerase Chain Reaction

Disciplines

Biochemistry, Biophysics, and Structural Biology | Life Sciences | Medicine and Health Sciences

Abstract

GLUT1-catalyzed equilibrative sugar transport across the mammalian blood-brain barrier is stimulated during acute and chronic metabolic stress; however, the mechanism of acute transport regulation is unknown. We have examined acute sugar transport regulation in the murine brain microvasculature endothelial cell line bEnd.3. Acute cellular metabolic stress was induced by glucose depletion, by potassium cyanide, or by carbonyl cyanide p-trifluoromethoxyphenylhydrazone, which reduce or deplete intracellular ATP within 15 min. This results in a 1.7-7-fold increase in V(max) for zero-trans 3-O-methylglucose uptake (sugar uptake into sugar-free cells) and a 3-10-fold increase in V(max) for equilibrium exchange transport (intracellular [sugar] = extracellular [sugar]). GLUT1, GLUT8, and GLUT9 mRNAs are detected in bEnd.3 cells where GLUT1 mRNA levels are 33-fold greater than levels of GLUT8 or GLUT9 mRNA. Neither GLUT1 mRNA nor total protein levels are affected by acute metabolic stress. Cell surface biotinylation reveals that plasma membrane GLUT1 levels are increased 2-3-fold by metabolic depletion, although cell surface Na(+),K(+)-ATPase levels remain unaffected by ATP depletion. Treatment with the AMP-activated kinase agonist, AICAR, increases V(max) for net 3-O-methylglucose uptake by 2-fold. Glucose depletion and treatment with potassium cyanide, carbonyl cyanide p-trifluoromethoxyphenylhydrazone, and AICAR also increase AMP-dependent kinase phosphorylation in bEnd.3 cells. These results suggest that metabolic stress rapidly stimulates blood-brain barrier endothelial cell sugar transport by acute up-regulation of plasma membrane GLUT1 levels, possibly involving AMP-activated kinase activity.

Rights and Permissions

Citation: J Biol Chem. 2010 May 14;285(20):15430-9. Epub 2010 Mar 15. Link to article on publisher's website

Related Resources

Link to article in PubMed

PubMed ID

20231288