当前位置： SCI文献检索 > Advances in Experimental Medicine and Biology期刊下所有文献 > High glucose activates ChREBP-mediated HIF-1α and VEGF expression in human RPE cells under normoxia.

High glucose activates ChREBP-mediated HIF-1α and VEGF expression in human RPE cells under normoxia.

Abstract：

OBJECTIVE:Because retina-damaging angiogenesis is controlled by vascular endothelial growth factor (VEGF) and people with higher glucose intakes are more susceptible to retinal complications that may be due to increased VEGF, it is crucial to elucidate relations between glucose exposure and VEGF expression. We aimed to determine if a carbohydrate response element binding protein (ChREBP) plays a role in the transcriptional up-regulation of hypoxia-inducible factor-1α (HIF-1α) and the downstream VEGF expression in retinal pigment epithelial (RPE) cells exposed to high glucose under normoxic conditions. METHODS:ARPE19 cells were exposed to 5.6, 11, 17, 25 and 30 mM glucose for 48 h in serum-free culture media under normoxic (21 % O2) conditions. Protein and mRNA expression of indicated genes were determined by immunoblot analyses and real-time RT-PCR, respectively. An enzyme-linked immunosorbent assay (ELISA) was used to detect the concentrations of VEGF in the media. Immunofluorescence (IF) and chromatin immunoprecipitation (ChIP) for ChREBP were used to demonstrate nuclear translocation and HIF-1α gene promoter association, respectively. RESULTS:Immunoblot analyses showed that HIF-1α levels were positively related to levels of glucose exposure between 5.6-25 mM in the RPE cells, indicating the induction and stabilization of HIF-1α by elevated glucose under normoxic conditions. Human lens epithelial cells and HeLa cells did not respond to high glucose, implying that this phenomenon is cell type-specific. Real-time RT-PCR for HIF-1α and VEGF and ELISA for VEGF indicated that high glucose is associated with elevated production of HIF-1α-induced VEGF, an established inducer of neovascularization, in the RPE cells. IF analyses showed that, although ChREBP was expressed under both low (5.6 mM) and high (25 mM) glucose conditions, it appeared more in the nuclear region than in the cytosol of the RPE cells after the high glucose treatment. ChIP analyses suggested a HIF-1α gene promoter association with ChREBP under the high glucose condition. These results imply that RPE cells use cytosolic ChREBP as a glucose sensor to up-regulate HIF-1α expression. CONCLUSION:These results suggest a high glucose-induced, ChREBP-mediated, and normoxic HIF-1α activation that may be partially responsible for neovascularization in both diabetic and age-related retinopathy.

journal_name

Adv Exp Med Biol

journal_title

Advances in experimental medicine and biology

authors

Chang ML,Chiu CJ,Shang F,Taylor A

doi

10.1007/978-1-4614-3209-8_77

subject

Has Abstract

pub_date

2014-01-01 00:00:00

pages

609-21

eissn

0065-2598

issn

2214-8019

journal_volume

801

pub_type

杂志文章

在线工具

High glucose activates ChREBP-mediated HIF-1α and VEGF expression in human RPE cells under normoxia.