Expression of conventional and novel glucose transporters, GLUT1, -9, -10, and -12, in vascular smooth muscle cells

Am J Physiol Cell Physiol. 2013 Mar;304(6):C574-89. doi: 10.1152/ajpcell.00275.2012. Epub 2013 Jan 9.

Abstract

Intimal hyperplasia is characterized by exaggerated proliferation of vascular smooth muscle cells (VSMCs). Enhanced VSMC growth is dependent on increased glucose uptake and metabolism. Facilitative glucose transporters (GLUTs) are comprised of conventional GLUT isoforms (GLUT1-5) and novel GLUT isoforms (GLUT6-14). Previous studies demonstrate that GLUT1 overexpression or GLUT10 downregulation contribute to phenotypic changes in VSMCs. To date, the expression profile of all 14 GLUT isoforms has not been fully examined in VSMCs. Using the proliferative and differentiated phenotypes of human aortic VSMCs, the present study has determined the relative abundance of GLUT1-14 mRNAs by quantitative real-time PCR analysis. Twelve GLUT mRNAs excluding GLUT7 and GLUT14 were detectable in VSMCs. In the proliferative phenotype, the relative abundance of key GLUT mRNAs was GLUT1 (∼43%)>GLUT10 (∼26%)>GLUT9 (∼13%)>GLUT12 (∼4%), whereas in the differentiated phenotype the relative abundance was GLUT10 (∼28%)>GLUT1 (∼25%)>GLUT12 (∼20%)>GLUT9 (∼14%), together constituting 86-87% of total GLUT transcripts. To confirm the expression of key GLUT proteins, immunoblot and immunocytochemical analyses were performed using GLUT isoform-specific primary antibodies. The protein bands characteristic of GLUT1, -9, -10, and -12 were detected in VSMCs in parallel with respective positive controls. In particular, GLUT1 protein expression showed different molecular forms representative of altered glycosylation. While GLUT1 protein displayed a predominant distribution in the plasma membrane, GLUT9, -10, and -12 proteins were mostly distributed in the intracellular compartments. The present study provides the first direct evidence for GLUT9 and GLUT12 expression in VSMCs in conjunction with the previously identified GLUT1 and GLUT10.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aorta / metabolism
  • Cell Differentiation
  • Cell Proliferation
  • Glucose Transport Proteins, Facilitative / genetics
  • Glucose Transport Proteins, Facilitative / metabolism*
  • Glucose Transporter Type 1 / genetics
  • Glucose Transporter Type 1 / metabolism*
  • Humans
  • Muscle, Smooth, Vascular / cytology
  • Muscle, Smooth, Vascular / metabolism*
  • Phenotype
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism

Substances

  • Glucose Transport Proteins, Facilitative
  • Glucose Transporter Type 1
  • Protein Isoforms
  • SLC2A1 protein, human
  • SLC2A10 protein, human
  • SLC2A12 protein, human
  • SLC2A9 protein, human