Thymosin beta 4 suppression of corneal NFκB:: A potential anti-inflammatory pathway

The purpose of this study was to determine the effect of thymosin beta 4 (T beta(4)) on NF kappa B protein levels, activation, phosphorylation, and nuclear translocation in a model of tumor necrosis factor (TNF)-alpha-mediated corneal inflammation. Transformed and primary (HCET and HCEC) human corneal epithelial cells were stimulated with the pro-inflammatory cytokine TNF-alpha and treated or not with T beta(4). Nuclear NF kappa B p65 subunit protein levels were assayed using ELISA, and activity was measured by determining NF kappa B binding to consensus oligonucleotides. NF kappa B p65 protein phosphorylation was also measured by ELISA. Nuclear translocation of NF kappa B p65 subunit was assayed by immunofluorescence microscopy. Compared to non-treated controls, T beta(4) treatment significantly decreased nuclear NF kappa B protein levels, NF kappa B activity and p65 subunit phosphorylation in corneal epithelial cells after TNF-alpha stimulation. In TNF-alpha-stimulated corneal epithelial cells, NF kappa B p65 subunit translocation to the nucleus was observed using immunofluorescence microscopy. In contrast, T beta(4) blocked nuclear translocation of the NF kappa B p65 subunit in TNF-alpha-stimulated corneal epithelial cells. TNF-alpha initiates cell signaling pathways that converge on the activation of NF kappa B, thus both are known mediators of the inflammatory process. T beta(4) a protein with diverse cellular functions including wound healing and suppression of inflammation, inhibits the activation of NF kappa B in TNF-alpha-stimulated cells. These results have important clinical implications for the potential role of T beta(4) as a corneal anti-inflammatory agent. (c) 2006 Elsevier Ltd. All rights reserved.