IL-1β induces IL-6 production in retinal Müller cells predominantly through the activation of p38 MAPK/NF-κB signaling pathway.

Abstract

IL-6 plays an important role in various inflammatory ocular diseases, including diabetic retinopathy. Müller cells are the major source of inflammatory mediators, including IL-6, in the retina. However, the mechanism of regulating IL-6 production in these cells remains unclear. Examination of signaling pathways in human retinal Müller cells (MIO-M1 cell line) cultured with IL-1β, TNF-α, IL-6, IL-8, VEGF, IFN-γ, glucose or mannitol showed that IL-1β was the most potent stimulator of IL-6 production. In addition, IL-1 β also increased NF-κB p50 protein level and phosphorylation of p38 MAPK, ERK1/2 and c-Jun. Induction of IL-6 production by IL-1β was significantly reduced by addition of p38 MAPK (SB203580), MEK1/2 (U0126) or NF-κB (BAY11-7082) inhibitors, with the highest effect being observed with SB203580. To explore the specific elements in IL-6 promoter responsible for IL-1β-induction of IL-6 expression, a series of plasmids bearing various IL-6 promoter mutations were transiently expressed in MIO-MI cells cultured in the presence or absence of IL-1β (10ng/ml) and/or SB203580 (10µM). Results showed that IL-6 promoter activity of the parent pIL-6-Luc651 was significantly enhanced by IL-1β, but the level was significantly attenuated by SB203580. Furthermore, the IL-6 promoter activity was also reduced upon deletion of NF-κB, AP-1 or C/EBP binding sites, with NF-κB deletion being the greatest. These results are the first demonstration that IL-1β induces IL-6 production in Müller cells by activation of IL-6 promoter activity predominantly through the p38 MAPK/NF-κB pathway.

• Authors: Xiufen Liu, Fei Ye, Huabao Xiong, Dan-Ning Hu, G Astrid Limb, Tian Xie, Liang Peng, Pili Zhang, Yi Wei, Wiley Zhang, Juan Wang, Hongwei Wu, Peng Lee, E Song, David Y Zhang
• Journal: Experimental cell research (Exp Cell Res) Vol. 331 Issue 1 Pg. 223-231 (Feb 01 2015) ISSN: 1090-2422 [Electronic] United States
• PMID: 25239226 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2014 Elsevier Inc. All rights reserved.

Chemical References

• Interleukin-1beta
• Interleukin-6
• NF-kappa B
• RNA, Messenger
• Luciferases
• p38 Mitogen-Activated Protein Kinases

Topics

• Blotting, Western
• Cell Proliferation
• Cells, Cultured
• Humans
• Interleukin-1beta (pharmacology)
• Interleukin-6 (genetics, metabolism)
• Luciferases (metabolism)
• NF-kappa B (genetics, metabolism)
• Phosphorylation (drug effects)
• Promoter Regions, Genetic (genetics)
• RNA, Messenger (genetics)
• Real-Time Polymerase Chain Reaction
• Retina (cytology, drug effects, metabolism)
• Reverse Transcriptase Polymerase Chain Reaction
• Signal Transduction (drug effects)
• p38 Mitogen-Activated Protein Kinases (genetics, metabolism)