TY - JOUR
T1 - Concerted inhibition of HIF-1α and -2α expression markedly suppresses angiogenesis in cultured RPE cells
AU - Nakajima, Takeshi
AU - Nakajima, Emi
AU - Shearer, Thomas R.
AU - Azuma, Mitsuyoshi
N1 - Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2013/11
Y1 - 2013/11
N2 - HIF-1α is known to play an important role in the induction of VEGF by hypoxia in retinal pigment epithelial (RPE) cells. However, the involvement of the other isoform, HIF-2α, in RPE cells remains unclear. Thus, the purpose of present study was to clarify the role of HIF-2α during induction of angiogenic genes in hypoxic RPE cells. When human RPE cells (ARPE-19) were cultured under hypoxic conditions, HIF-1α and HIF-2α proteins increased. This induced an increase in mRNA for VEGF, causing secretion of VEGF protein into the medium. This conditioned medium induced tube formation in human vascular endothelial cells (HUVEC). The increased expression of mRNA for VEGF in hypoxic RPE cells was partially inhibited by HIF-1α siRNA, but not by HIF-2α siRNA. However, co-transfection of HIF-1α siRNA and HIF-2α siRNA augmented downregulation of VEGF mRNA and protein in hypoxic RPE cells and inhibited formation of tube-like structures in HUVEC. GeneChip and PCR array analyses revealed that not only VEGF, but also expression of other angiogenic genes were synergistically downregulated by co-transfection of hypoxic RPE cells with HIF-1α and HIF-2α siRNAs. These findings suggest an important compensatory role for the HIF-2α isoform in the regulation of angiogenic gene expression. Thus, suppression of angiogenic genes for HIF-1α and HIF-2α may be a possible therapeutic strategy against retinal angiogenesis in Age-related macular degeneration (ARMD).
AB - HIF-1α is known to play an important role in the induction of VEGF by hypoxia in retinal pigment epithelial (RPE) cells. However, the involvement of the other isoform, HIF-2α, in RPE cells remains unclear. Thus, the purpose of present study was to clarify the role of HIF-2α during induction of angiogenic genes in hypoxic RPE cells. When human RPE cells (ARPE-19) were cultured under hypoxic conditions, HIF-1α and HIF-2α proteins increased. This induced an increase in mRNA for VEGF, causing secretion of VEGF protein into the medium. This conditioned medium induced tube formation in human vascular endothelial cells (HUVEC). The increased expression of mRNA for VEGF in hypoxic RPE cells was partially inhibited by HIF-1α siRNA, but not by HIF-2α siRNA. However, co-transfection of HIF-1α siRNA and HIF-2α siRNA augmented downregulation of VEGF mRNA and protein in hypoxic RPE cells and inhibited formation of tube-like structures in HUVEC. GeneChip and PCR array analyses revealed that not only VEGF, but also expression of other angiogenic genes were synergistically downregulated by co-transfection of hypoxic RPE cells with HIF-1α and HIF-2α siRNAs. These findings suggest an important compensatory role for the HIF-2α isoform in the regulation of angiogenic gene expression. Thus, suppression of angiogenic genes for HIF-1α and HIF-2α may be a possible therapeutic strategy against retinal angiogenesis in Age-related macular degeneration (ARMD).
KW - Age-related macular degeneration
KW - Hypoxia
KW - Hypoxia-inducible factor-1α and -2α
KW - Retinal pigment epithelial cells
KW - Vascular endothelial growth factor
UR - http://www.scopus.com/inward/record.url?scp=84885418780&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84885418780&partnerID=8YFLogxK
U2 - 10.1007/s11010-013-1760-1
DO - 10.1007/s11010-013-1760-1
M3 - Article
C2 - 23873332
AN - SCOPUS:84885418780
SN - 0300-8177
VL - 383
SP - 113
EP - 122
JO - Molecular and Cellular Biochemistry
JF - Molecular and Cellular Biochemistry
IS - 1-2
ER -