Upregulation of Fc?RIIB by resveratrol via NF-?B activation reduces B-cell numbers and ameliorates lupus.
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ABSTRACT: 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. Fc?RIIB, 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 Fc?RIIB develop lupus-like diseases, we investigated whether resveratrol can alleviate lupus through Fc?RIIB. We found that resveratrol enhanced the expression of Fc?RIIB 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 Fc?RIIB by resveratrol involved an increase of Sirt1 protein and deacetylation of p65 NF-?B (K310). Moreover, increased binding of phosphor-p65 NF-?B (S536) but decreased association of acetylated p65 NF-?B (K310) and phosphor-p65 NF-?B (S468) to the -480 promoter region of Fcgr2b gene was responsible for the resveratrol-mediated enhancement of Fc?RIIB 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 Fc?RIIB expression in B cells via resveratrol can selectively reduce B cells, decrease serum autoantibodies and ameliorate lupus nephritis. Our findings lead us to propose Fc?RIIB as a new target for therapeutic exploitation, particularly for lupus patients whose Fc?RIIB expression levels in B cells are downregulated.
SUBMITTER: Jhou JP
PROVIDER: S-EPMC5628277 | biostudies-literature | 2017 Sep
REPOSITORIES: biostudies-literature
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