Subtoxic levels hydrogen peroxide-induced production of interleukin-6 by retinal pigment epithelial cells

作者：Wu Wen Chuan; Hu Dan Ning^*; Gao Hua Xin; Chen Min; Wang Dawei; Rosen Richard; McCormick Steven A

来源：Molecular Vision, 2010, 16(200-02): 1864-1873.

Purpose: To study the effect of subtoxic levels of hydrogen peroxide (H(2)O(2)) on the expression and release of interleukin-6 (IL-6) by cultured retinal pigment epithelial (RPE) cells and to explore the relevant signal pathways.
Methods: Cultured human RPE cells were stimulated with various subtoxic concentrations of H(2)O(2) for different periods. Conditioned medium and cells were collected. IL-6 in the medium and IL-6 mRNA in the collected cells were measured using an IL-6 enzyme-linked immunosorbent assay kit and reverse transcriptase polymerase chain reaction, respectively. Nuclear factor-kappaB (NF-kappa B) in nuclear extracts and phosphorylated p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinases (JNK) in cells cultured with and without H(2)O(2) were measured by NF-kappa B and MAPK enzyme-linked immunosorbent assay kits. Inhibitors of p38 (SB203580), ERK (UO1026), JNK (SP600125), and NF-kappa B (BAY11-7082) were added to the cultures before the addition of H(2)O(2) to test their effects.
Results: Subtoxic levels of H(2)O(2) (100 mu M and less) increased the IL-6 mRNA level and the release of IL-6 protein by the cultured human RPE cells in a dose-and time-dependent manner. This was accompanied by an increase of NF-kappa B in nuclear extracts and phosphorylated p38 MAPK, ERK, and JNK in cell lysates, particularly in the p38 and NF-kappa B. The NF-kappa B inhibitor decreased the H(2)O(2)-induced expression of IL-6. The p38 inhibitor, but not the ERK or JNK inhibitor, completely abolished H(2)O(2)-induced expression of IL-6 by RPE cells. The p38 inhibitor also abolished the increase of NF-kappa B in nuclear extracts in cells treated with H(2)O(2).
Conclusions: H(2)O(2) stimulated the production of IL-6, a key factor in the modulation of immune responses, inflammatory processes, and the occurrence of autoimmune diseases, which recently has been documented to be increased in age-related macular degeneration (AMD). This may be a molecular linkage for the oxidative stress and inflammatory/autoimmune reactions in AMD and may provide a novel target for the treatment of AMD.

• 出版日期2010-9-12