Complement Stimulates Retinal Pigment Epithelial Cells to Undergo Pro-Inflammatory Changes

• Published in: Ophthalmic research Vol. 54; no. 4; pp. 195 - 203
• Main Authors: Lueck, Katharina, Busch, Martin, Moss, Stephen E., Greenwood, John, Kasper, Maren, Lommatzsch, Albrecht, Pauleikhoff, Daniel, Wasmuth, Susanne
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01.01.2015
• Subjects: Blotting, Western; Cells, Cultured; Complement Membrane Attack Complex - metabolism; Complement System Proteins - physiology; Cytokines - metabolism; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Humans; Immunohistochemistry; Inflammation Mediators - metabolism; Intercellular Adhesion Molecule-1 - metabolism; Macular Degeneration - metabolism; NF-kappa B - metabolism; Original Paper; Real-Time Polymerase Chain Reaction; Retinal Pigment Epithelium - metabolism; Vascular Cell Adhesion Molecule-1 - metabolism; Inflammation; Complement; Retinal pigment epithelium
• ISSN: 0030-3747; 1423-0259
• DOI: 10.1159/000439596

Background/Aims: We examined the effect of human complement sera (HCS) on retinal pigment epithelial (RPE) cells with respect to pro-inflammatory mediators relevant in early age-related macular degeneration (AMD). Methods: RPE cells were treated with complement-containing HCS or with heat-inactivated (HI) HCS or C7-deficient HCS as controls. Cells were analysed for C5b-9 using immunocytochemistry and flow cytometry. Interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1 (MCP-1) were quantified by ELISA and RT-PCR. Tumour necrosis factor-a (TNF-a), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), were analysed by Western blotting. The intracellular distribution of nuclear factor (NF)-κB was investigated by immunofluorescence. Results: A concentration-dependent increased staining for C5b-9 but no influence on cell viability was observed after HCS treatment. ELISA and RT-PCR analysis revealed elevated secretion and expression of IL-6, IL-8, and MCP-1. Western blot analysis showed a concentration-dependent increase in ICAM-1, VCAM-1, and TNF-a in response to HCS, and immunofluorescence staining revealed nuclear translocation of NF-κB. Conclusion: This study suggests that complement stimulates NF-κB activation in RPE cells that might further create a pro-inflammatory environment. All these factors together may support early AMD development.