stilbenes and Lupus-Nephritis

Resveratrol, an anti-inflammatory agent, can inhibit pro-inflammatory mediators by activating Sirt1, which is a class III histone deacetylase. However, whether resveratrol can regulate inhibitory or anti-inflammatory molecules has been less studied. FcγRIIB, a receptor for IgG, is an essential inhibitory receptor of B cells for blocking B-cell receptor-mediated activation and for directly inducing apoptosis of B cells. Because mice deficient in either Sirt1 or FcγRIIB develop lupus-like diseases, we investigated whether resveratrol can alleviate lupus through FcγRIIB. We found that resveratrol enhanced the expression of FcγRIIB in B cells, resulting in a marked depletion of plasma cells in the spleen and notably in the bone marrow, thereby decreasing serum autoantibody titers in MRL/lpr mice. The upregulation of FcγRIIB by resveratrol involved an increase of Sirt1 protein and deacetylation of p65 NF-κB (K310). Moreover, increased binding of phosphor-p65 NF-κB (S536) but decreased association of acetylated p65 NF-κB (K310) and phosphor-p65 NF-κB (S468) to the -480 promoter region of Fcgr2b gene was responsible for the resveratrol-mediated enhancement of FcγRIIB gene transcription. Consequently, B cells, especially plasma cells, were considerably reduced in MRL/lpr mice, leading to improvement of nephritis and prolonged survival. Taken together, we provide evidence that pharmacological upregulation of FcγRIIB expression in B cells via resveratrol can selectively reduce B cells, decrease serum autoantibodies and ameliorate lupus nephritis. Our findings lead us to propose FcγRIIB as a new target for therapeutic exploitation, particularly for lupus patients whose FcγRIIB expression levels in B cells are downregulated.

Topics: Animals; Anti-Inflammatory Agents; Autoantibodies; B-Lymphocytes; Cell Membrane; Disease Models, Animal; Gene Expression Regulation; Lupus Erythematosus, Systemic; Lupus Nephritis; Mice; Mice, Inbred MRL lpr; Models, Biological; Myeloid Cells; NF-kappa B; Promoter Regions, Genetic; Receptors, IgG; Resveratrol; Splenomegaly; Stilbenes; Survival Rate; Transcriptional Activation

(E)-2-(2-chlorostyryl)-3,5,6-trimethylpyrazine (CSTMP), a novel stilbene derivative, have been shown to have cytoprotective effects against H2O2-induced oxidative stress in human endothelial cells. However, little is known about its anti-inflammatory effects in lupus nephritis (LN). In the present study, we investigated the anti-inflammatory effects of CSTMP on lipopolysaccharide (LPS)-induced human renal proximal tubular epithelial cells (hRPTECs) and elucidated its molecular mechanisms. CSTMP significantly attenuated the cytotoxicity and suppressed the release of proinflammatory mediators, including iNOS, COX-2, TNF-α, IL-6, IL-8, CCL-2, ICAM-1, IL-1β, and MCP-1 in LPS-induced hRPTECs. In addition, CSTMP decreased the expression of TLR4 and its adapter molecules (MyD88, phosphorylation of TAK1, TRAF6, and IRAK1) and abolished its interactions with these adapter molecules in LPS-induced hRPTECs, resulting in an inhibition of the TLR4/MyD88/TAK1/ TRAF6/IRAK1 complex. Moreover, CSTMP also attenuated phosphorylation of IκB and IKK-α/β, and P50-NF-κB and P65-NF-κB translocation to nucleus in LPS-induced hRPTECs. These findings provided new insights to understand the mode of action of CSTMP in treatment of inflammatory diseases, such as LN.

Topics: Active Transport, Cell Nucleus; Anti-Inflammatory Agents; Cells, Cultured; Epithelial Cells; Humans; Hydrogen Peroxide; I-kappa B Kinase; Inflammation Mediators; Interleukin-1 Receptor-Associated Kinases; Kidney Tubules, Proximal; Lipopolysaccharides; Lupus Nephritis; MAP Kinase Kinase Kinases; Myeloid Differentiation Factor 88; NF-kappa B; NF-kappa B p50 Subunit; NF-KappaB Inhibitor alpha; Oxidative Stress; Phosphorylation; Pyrazines; Stilbenes; TNF Receptor-Associated Factor 6; Toll-Like Receptor 4; Transcription Factor RelA