Apelin-13 regulates proliferation, migration and survival of retinal Müller cells under hypoxia
2013
Lu, Qiang | Jiang, Yan-rong | Qian, Jing | Tao, Yong
AIMS: To investigate the effect of apelin-13 and the antagonist of apelin receptor (F13A) on retinal Müller cells in vitro. METHODS: Localization of apelin-13, GFAP and VEGF of Müller cells was detected by immunofluorescence. The effects of apelin-13 and F13A on cell function were assessed by MTT, spreading assay, apoptosis and Boyden chamber assay in vitro. Additionally, the mRNA and protein of apelin-13, GFAP and VEGF in cultured Müller cells were measured by real-time PCR and western blot. RESULTS: Under hypoxia, strong positive staining of apelin-13 was observed and particularly evident in the cytosol and around the nucleus. Exposure of Müller cells to hypoxia led to a progressive increase in mRNA (p<0.01) and protein levels of apelin-13 (p<0.01), with a maximal 2.5-fold and 2-fold stimulation at 4h respectively, compared with normoxic controls. Treated with 0.1, 1, 10 and 100ng/ml apelin-13, the protein level of GFAP (p<0.01) and VEGF (p<0.01) increased significantly in Müller cells in a dose-dependent manner after 24h. Compared with the untreated cells, 10ng/ml apelin-13 significantly promoted Müller cells migration (p<0.01). Annexin/PI staining showed that apelin-13 can downregulate cell apoptosis with 30% to the most (p<0.05). On the contrary, 20ng/ml F13A-treated Müller cells spread less than the control cells, with significantly lower number of migrated cells and significantly higher rate of apoptosis. CONCLUSIONS: The results of this study showed that apelin-13 modulated the proliferation, migration, spreading, survival of Müller cells and the expressions of GFAP and VEGF.
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