Hypoxia-inducible factor-1alpha and -2alpha additively promote endothelial vasculogenic properties.
OBJECTIVE
While both play a role in the transcriptional response of hypoxic endothelial cells (ECs), hypoxia-inducible factor-1alpha (HIF-1alpha) and HIF-2alpha differ in their transactivation sites, pointing at potentially different target genes. We studied the discrete and common effects of HIF-1alpha and HIF-2alpha on the cytokine expression and vasculogenic properties of ECs.


RESULTS
H5V and bovine aortic ECs were transfected to express HIF-1alpha, HIF-2alpha or both. Overexpression of HIF-1alpha or HIF-2alpha and, to a greater extent, cotransfection of HIF-1alpha and HIF-2alpha resulted in EC activation, as revealed by analysis of the adhesion capacities and adhesion molecule surface expression of ECs. From the paracrine aspect, conditioned medium from HIF-expressing ECs was found to promote the migration and tube formation capacity of wild-type ECs, mostly following HIF-1alpha and HIF-2alpha coexpression. Antibody arrays revealed altered expression of multiple cytokines, pointing at consistent additive effects of HIF-1alpha and HIF-2alpha on angiogenic protein expression. Finally, HIF-1alpha and HIF-2alpha additively promoted vessel formation in vivo, as demonstrated by a Matrigel angiogenesis assay.


CONCLUSIONS
Our results further clarify the functional roles of HIF-1alpha and HIF-2alpha in ECs and for the first time demonstrate a common contribution of HIF-1alpha and HIF-2alpha to vasculogenesis.
Ben-Shoshan
Jeremy
J
Department of Cardiology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
Maysel-Auslender
Sofia
S
Luboshits
Galia
G
Barshack
Iris
I
Polak-Charcon
Sylvie
S
Tzahor
Eldad
E
Keren
Gad
G
George
Jacob
J
D042501:Angiogenic Proteins / Q000378:metabolism; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000378:metabolism; D015687:Cell Hypoxia; D002465:Cell Movement; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D042783:Endothelial Cells / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic; D019899:Paracrine Communication; D014162:Transfection; D000099162:Endothelial PAS Domain-Containing Protein 1
D042501:Angiogenic Proteins; D051792:Basic Helix-Loop-Helix Proteins; D015815:Cell Adhesion Molecules; D017077:Culture Media, Conditioned; D016207:Cytokines; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D000099162:Endothelial PAS Domain-Containing Protein 1; C497442:HIF1A protein, human