Involvement of p38 MAP kinase in ET–1 Mediated Apoptosis of Retinal Ganglion Cells.

Abstract

Abstract: : Purpose: Previous studies from our laboratory have shown ET–1 treatment promotes apoptosis of cultured rat retinal ganglion cells. The purpose of this study was to determine if p38 MAP kinase is involved in ET–1 mediated apoptosis of retinal ganglion cells. Methods: Virally transformed rat retinal ganglion cells (RGC5) were treated with 100nM ET–1 for 5, 10 and 15 min. Activation of p38 MAP Kinase was determined by immunoblotting using anti phospho p38 antibody. p38 MAP kinase assay was carried out using ATF–2 as substrate in the presence of γ ³²P. In addition, the kinase assay samples were separated by SDS /PAGE (10%) and radioactivity incorporated into ATF2 was detected by autoradiography. Results: An increase in p38 phosphorylation was observed following ET–1 (100nM) treatment for 5 min in RGC5 cells, which was restored to near control levels by 10 min. A corresponding increase in ATF–2 phosphorylation at 5 min was observed.The autradiography results of ATF–2 showed a similar increase in phosphorylation of ATF2 after ET–1 treatment for 5 min. Conclusions:Activation of p38 MAP Kinase in RGC5 cells following treatment with ET–1 (100nM) may contribute to ET–1 mediated apoptosis in RGC5 cells.

Keywords: apoptosis/cell death • ganglion cells • signal transduction