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Title:
Autophagy Promotes the Expression of Vascular Endothelial Growth Factor in Human Retinal Pigment Epithelium Cells
Authors:  Xinhong Chai, B.S., Xia Li, M.D., Mengyang Kang, B.S., Xiaoye Wang, B.S., and Junhui Du, M.D.
  Objective: To investigate the effects of autophagy on vascular endothelial growth factor (VEGF) expression in human retinal pigment epithelial cells (RPE-19) under the condition of hypoxia in vitro.
Study Design:
RPE-19 cells were divided into 3 groups: control group, hypoxia group (the final concentration of CoCl2 in the medium was 125 μmol/L), and autophagy inhibitor group (cells were pretreated with 3-methyladenine for 12 hours and then cultured with 125 μmol/L CoCl2). After 24 hours, enzyme-linked immunosorbent assay (ELISA) and western blotting were used to detect the expression levels of VEGF. The expression of autophagy correlation protein Beclin 1, LC3 (LC3-II/LC3-I ratio), and p62 were examined by western blotting. Then, we increased autophagy level using rapamycin to detect its effect on VEGF in the condition of normal oxygen culture (cells were pre-treated by 500 nM rapamycin for 12 hours); the expression level of VEGF was detected by the above method.
Results:
Compared with the control group, expres-sion of VEGF, Beclin-1, and LC3II/I protein were increased while p62 was decreased under hypoxia. VEGF protein expression and secretion were decreased in the autophagy inhibitor group. Furthermore, we found that rapamycin also promoted the expression and secretion of VEGF protein.
Conclusion:
Autophagy promoted the expression of VEGF in RPE-19 cells. Targeting autophagy is expected to upregulate VEGF levels in RPE cells.
Keywords:  autophagy; Beclin-1; choroidal neovascularization; hypoxia; hypoxia in vitro; intraocular neovascularization; neovascularization; ophthalmic diseases; retinal pigment epithelial; VEGF; vascular endothelial growth factor; vision loss
   
   
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