Involvement of Intracellular Calcium Mobilization in IL-8 Activation in Human Retinal Pigment Epithelial Cells

PURPOSE. Calcium signaling is an important intracellular pathway. Increased intracellular calcium is associated with cytokine regulation and inflammatory signals secretion. The purpose of this study is to understand the molecular mechanisms by which calcium signaling controls IL-8 activation in human RPE cells. METHODS. Fluorescence-based calcium imaging and different mutants of IL-8 plasmids were used in this study. The IL-8 promoter activation, gene expression, and secretion were detected by using luciferase reporter assay, quantitative real-time PCR (Q-PCR), and ELISA, respectively. In addition, pharmacological inhibitors and small interfering RNA (siRNA) were applied to clarify the mechanisms of IL-8 activation. RESULTS. Our study reported that intracellular calcium mobilization activated IL-8 gene expression and secretion. Application of pharmacological inhibitor BAY 11-7082, siRNA, and plasmids of the nuclear factor j light chain enhancer of activated B cells (NF-jB) binding site, we identified that NF-kappa B is the main transcription factor involved in intracellular calcium mobilization-mediated IL-8 activation in human RPE cells. CONCLUSIONS. Collectively, our findings highlight the important role of intracellular calcium mobilization in the activation of IL-8. These findings may be helpful for the clinical applications in the age-related macular degeneration (AMD) prevention and treatment.