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Toshiaki Abe, Aya Katsuyama, Shinji Yamada, Yuki Katsukura, Zhaleh Nezhad, Nobuhiro Nagai; A non-histone nuclear protein enhances VEGF expression and choroidal neovascularization. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5793.
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© ARVO (1962-2015); The Authors (2016-present)
VEGF is one of the main factors that induces angiogenesis and anti-VEGF therapy has introduced for clinic in good results, such as in patients with AMD. The complicated mechanism of the pathophysiology to enhance the VEGF expression, however, is still waited to be determined. We planned to elucidate the forcing factors to enhance the VEGF expression using retinal pigment epithelial cells (RPE) and genetically modified mice model.
RPE cells with or without hypoxia-responsive element flanked EGFP vector were treated by prolonged low oxygen (2% O2; OD) or low oxygen with glucose deprivation (OGD) using RPE cell line (ARPE). Liquid chromatography/mass spectrometry/mass spectrometry was performed between OD and OGD using nuclear extracts. Fluorescein photography, western blotting, real-time PCR, ELISA, cell viability and RNA inhibiting experiments were performed. HMGN1tm1/tm1 was also used for choroidal neovascular (CNV) experiments.
VEGF expression in OGD was exponentially increased when compared to that of OD. LC-MS/MS, western blotting, ELISA and real-time PCR showed that high mobility group (HMG) proteins, especially HMGN1 was suspected to be one of the molecules to enhance VEGF expression in those condition. Phosphorylation but not acetylation of HMGN1 was observed to be increased in OGD. siRNA for HMGN1 but not other HMG-siRNA suppressed the VEGF expression and increased the cell viability of ARPE. The siRNA did not influence the EGFP expression. Statistically significant decrease of VEGF expression was observed in HMGtm/tm in RPE-choroid extracts when we perfomed laser treatments. Statistically significant decrease of the size of laser-induced CNV in the HMGN1tm1/tm1 was observed when compared to that of wild mice.
HMGN1, as one of the epigenetic modulator, may play a role in the generation of CNV through VEGF expression.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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