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.
Animals ; Apoptosis ; Autoantibodies ; B-Lymphocytes* ; Bone Marrow ; Histone Deacetylases ; Humans ; Immunoglobulin G ; Lupus Nephritis ; Mice ; Nephritis ; Plasma Cells ; Promoter Regions, Genetic ; Spleen ; Up-Regulation*

BACKGROUNDGenome-wide association studies for type 2 diabetes mellitus (T2DM) identified FTO gene as a locus conferring increased risk for common obesity in many populations with European ancestry. However, the involvement of FTO gene in obesity or T2DM related metabolic traits has not been consistently established in Chinese populations. The objective of this study was to investigate the association of FTO genetic polymorphisms with metabolic syndrome (MetS) in Han Chinese.

METHODSWe tested 41 FTO single nucleotide polymorphisms (SNPs) for association between FTO and MetS-related traits. There were a total of 236 unrelated subjects (108 cases and 128 controls), grouped according to the International Diabetes Federation (IDF) criteria.

RESULTSOf the 41 SNPs examined, only SNP rs8047395 exhibited statistical significance (P = 0.026) under a recessive model, after Bonferroni adjustment for multiple testing (OR 1.64, 95%CI 1.11-2.42; P = 0.014). The common distributions of this polymorphism among Chinese--with a minor allele frequency (MAF) of 36% in the control group versus 48% in the MetS group--greatly improved our test power in a relatively small sample size for an association study. Previously identified obesity- (or T2DM-) associated FTO SNPs were less common in Han Chinese and were not associated with MetS in this study. No significant associations were found between our FTO SNPs and any endophenotypes of MetS.

CONCLUSIONSA more common risk-conferring variant of FTO for MetS was identified in Han Chinese. Our study substantiated that genetic variations in FTO locus are involved in the pathogenesis of MetS.

Alpha-Ketoglutarate-Dependent Dioxygenase FTO ; Asian Continental Ancestry Group ; Female ; Genetic Predisposition to Disease ; genetics ; Genetic Variation ; genetics ; Genotype ; Haplotypes ; genetics ; Humans ; Male ; Metabolic Syndrome ; genetics ; Middle Aged ; Polymorphism, Single Nucleotide ; genetics ; Proteins ; genetics