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Biochim Biophys Acta. 2003 Apr 15;1626(1-3):10-8.

HIF-2alpha regulates glyceraldehyde-3-phosphate dehydrogenase expression in endothelial cells.

Author information

1
Department of Medicine, Section of Pulmonary and Critical Care, University of Wisconsin Medical School, 2590 Medical Sciences Center, 1300 University Avenue, Madison, WI 53706, USA. kkg@medicine.wisc.edu <kkg@medicine.wisc.edu>

Abstract

Endothelial cells (EC) express both hypoxia inducible factor-1alpha (HIF-1alpha) and -2alpha (HIF-2alpha), yet their roles in the EC hypoxic response are unclear. Hypoxia upregulates the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in EC through a 5' hypoxic regulatory element (HRE). We compared the upregulation of GAPDH in human lung microvascular EC to that in hep3B cells, another cell type known to express both HIF-1alpha and HIF-2alpha. GAPDH mRNA increased to a lesser extent in hypoxic hep3B cells than in EC, yet upregulation occurred through the same HRE that was active in EC. HIF-1alpha protein induction in response to hypoxia was similar in both cell types. In contrast, HIF-2alpha protein levels were upregulated to a greater extent and for a longer period of time by hypoxia in EC than in hep3B cells. Correspondingly, electrophoretic mobility supershift assays showed that, in EC, there was preferential binding of HIF-2alpha to the GAPDH HRE while, in hep3B cells, there was binding of both HIF-1alpha and HIF-2alpha. The preferential binding of HIF-2alpha to the GAPDH HRE in EC may account for their higher level of induction of GAPDH. These findings suggest that cell-specific patterns of HIF-1alpha and HIF-2alpha expression lead to cell-specific gene upregulation during hypoxia.

PMID:
12697324
DOI:
10.1016/s0167-4781(03)00049-6
[Indexed for MEDLINE]

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