NF-κB p65 and c-Rel subunits promote phagocytosis and cytokine secretion by splenic macrophages in cirrhotic patients with hypersplenism

Transcription factors of the nuclear factor-kappa B (NF-kappa B) family play a key role in various biological processes. In this study, we explored the role of NF-kappa B in the dysfunction of splenic macrophages in hypersplenism due to liver cirrhosis. By using confocal microscopic analysis, Western Blot, TransAM NF-kappa B ELISA, and chromatin immunoprecipitation (ChIP), we observed that NF-kappa B p65, p52, and c-Rel were activated in macrophages in patients with hypersplenism (hypersplenic macrophages). Transfection of hypersplenic macrophages with a kappa B/luciferase reporter plasmid showed that NF-kappa B complexes were functional. Using co-immunoprecipitation studies, we demonstrated that p65/c-Rel dimers were activated in hypersplenic macrophages. NF-kappa B activation inhibitor JSH-23 and the small interfering RNA (siRNA)-mediated p65, and c-Rel gene silencing significantly blocked phagocytosis and secretion in hypersplenic macrophages. Using promoter analysis and RNA interference, we found that many phagocytotic and hepatic fibrogenetic regulators, including interleukin (IL)-1 alpha, IL-1 beta, interferon-gamma (IFN-gamma), transforming growth factor-beta 1 (TGF-beta 1), and tumor necrosis factor-alpha (TNF-alpha), were regulated by NF-kappa B p65 and c-Rel in hypersplenic macrophages. Our findings demonstrate that NF-kappa B p65 and c-Rel play an important role in phagocytosis and secretion in hypersplenic macrophages. Activation of NF-kappa B p65 and c-Rel may be considered an important regulator of hypersplenism and liver cirrhosis. (C) 2012 Elsevier Ltd. All rights reserved.