Yu-Feng Qing

Association of TLR4 Gene rs2149356 Polymorphism with Primary Gouty Arthritis in a Case-Control Study

Background The toll-like receptor (TLR)4-interleukin1β (IL1β) signaling pathway is involved in the monosodium urate (MSU)-mediated inflammation. The aim of this present study was to determine whether the TLR4 gene rs2149356 SNP is associated with gouty arthritis (GA) susceptibility and whether rs2149356 SNP impacts the TLR4-IL1β signaling pathway molecules expression. Methods and Findings The rs2149356 SNP was detected in 459 GA patients and 669 control subjects (containing 459 healthy and 210 hyperuricemic subjects). Peripheral blood mononuclear cells (PBMCs) TLR4 mRNA and serum IL1β were measured in different genotype carriers, and correlations between TLR4 gene SNP and TLR4 mRNA, IL1β were investigated. The frequencies of the genotype and allele were significantly different between the GA and control groups (P<0.01, respectively). The TT genotype was associated with a significantly increased risk of GA (OR = 1.88); this finding was not influenced by making adjustments for the components of possible confounders (adjusted OR = 1.96). TLR4 mRNA and IL1β were significantly increased in the TT genotype from acute GA patients (P<0.05, respectively), and lipids were significantly different among three genotypes in the GA patients (P<0.05, respectively). Conclusions The TLR4 gene rs2149356 SNP might be associated with GA susceptibility, and might participate in regulating immune, inflammation and lipid metabolism. Further studies are required to confirm these findings.

Genome-wide association analysis identifies three new risk loci for gout arthritis in Han Chinese

Gout is one of the most common types of inflammatory arthritis, caused by the deposition of monosodium urate crystals in and around the joints. Previous genome-wide association studies (GWASs) have identified many genetic loci associated with raised serum urate concentrations. However, hyperuricemia alone is not sufficient for the development of gout arthritis. Here we conduct a multistage GWAS in Han Chinese using 4,275 male gout patients and 6,272 normal male controls (1,255 cases and 1,848 controls were genome-wide genotyped), with an additional 1,644 hyperuricemic controls. We discover three new risk loci, 17q23.2 (rs11653176, P=1.36 × 10−13, BCAS3), 9p24.2 (rs12236871, P=1.48 × 10−10, RFX3) and 11p15.5 (rs179785, P=1.28 × 10−8, KCNQ1), which contain inflammatory candidate genes. Our results suggest that these loci are most likely related to the progression from hyperuricemia to inflammatory gout, which will provide new insights into the pathogenesis of gout arthritis.

Expression of CC Chemokine Ligand 5 in Patients with Rheumatoid Arthritis and Its Correlation with Disease Activity and Medication

OBJECTIVE To determine the levels of CC chemokine ligand 5 (CCL5) in serum and synovial fluid (SF) from patients with rheumatoid arthritis (RA) and their relations with disease activity and medication. METHODS CCL5 in serum and SF was quantified by enzyme-linked immunosorbent assay (ELISA) in 28 RA patients and 21 osteoarthritis (OA) patients. In RA patients, the correlations of CCL5 levels in serum and SF with disease activity were analyzed. Meanwhile, the serum CCL5 levels among RA patients treated with disease-modifying antirheumatic drugs (DMARDs), Tripterygium Glucosides, and other Chinese herbs without disease-modifying effects were also compared. RESULTS CCL5 levels in both serum and SF of RA patients were significantly higher than those of OA patients (P < 0.05). Moreover, the level of CCL5 was higher in SF than that in serum of RA patients (P < 0.01). Serum CCL5 level was correlated significantly with the number of swollen joints (r = 0.3329, P < 0.05), erythrocyte sedimentation rate (r = 0.4001, P < 0.05), and C reactive protein (r = 0.3735, P < 0.01). In addition, the level of CCL5 had a trend of lower in patients treated with DMARDs or Tripterygium Glucosides than those treated with other Chinese herbs, although the difference was not significant among those patients due to the small number of patients in each group. CONCLUSIONS In RA patients, the expression of CCL5 increases and correlates with some clinical and laboratory parameters of RA, which indicate that CCL5 plays an important role in RA and may serve as a useful marker of disease activity. DMARDs and Tripterygium Glucosides might exert their clinical effects through reducing CCL5 production in RA.

IL-37 inhibits the production of pro-inflammatory cytokines in MSU crystal-induced inflammatory response

Acute gouty arthritis (AGA) is an auto-inflammatory disease characterized by resolving spontaneously, which suggests that negative feedback loops control inflammatory and immunological responses to monosodium urate (MSU) crystals. By now, the molecular mechanism for spontaneous resolution of acute GA remains unclear; this study was undertaken to evaluate whether IL-37 is involved in spontaneous resolution of AGA. A total of 45 acute GA (AGA),29 non-acute GA (NAGA) male patients and 82 male health control (HC) were involved in this study, we measured IL-7 expression in the peripheral blood mononuclear cells (PBMCs), together with levels of IL-1β, IL-6, IL-10, TNF-α and TGF-β1 in the serum. Further, we either inhibited IL-37 expression in human PBMCs with siRNA or over-expressed the cytokine in human macrophages. Pro-inflammatory cytokine IL-1β, IL-6, and TNF-α expressions were significantly higher in the AGA group than in the NAGA or HC group (P < 0.05, respectively). However, anti-inflammatory IL-37, TGF-β1, and IL-10 were greater in the NAGA group than in the AGA and HC groups (P < 0.05, respectively). Expression of IL-37 in MSU crystal-treated macrophages inhibited the expression of pro-inflammatory cytokines, whereas the abundance of these cytokines increased with silencing of endogenous IL-37 in human blood cells. However, anti-inflammatory TGF-β1 and IL-10 expressions in these supernatants were unaffected by over-expression or knockdown of IL-37. Our study indicates that IL-37 is an important anti-inflammatory cytokine in AGA by suppressing the production of pro-inflammatory cytokines. Thus, IL-37 may provide a novel research target for the pathogenesis and therapy of GA.

Clinical analysis of primary Sjögren’s syndrome complicating anemia

This is a cross-sectional study to assess the prevalence and causes of anemia in the primary Sjögren’s syndrome (pSS). One hundred and thirty-two consecutive patients with pSS were enrolled into the study. Standard hematological and immunological tests and examination of bone marrow were performed. Anemia occurred in 45 (34.1%) patients. The causes of anemia included anemia of chronic disease (69%), autoimmune hemolytic anemia (AIHA, 18%), iron deficiency anemia (9%) and other causes (4%), of which AIHA caused the most severe anemia. The prevalence of ANA, anti-Ro/SSA, and anti-La/SSB was much higher in patients with anemia than those without anemia. Anticardiolipin antibodies were most commonly detected in AIHA; the prevalence of IgG and hypocomplementemia in AIHA was much higher in patients without anemia. Abnormal bone marrow changes were observed in two cases with anemia, one with morphological changes in the myeloid, megakaryocytic, and erythroid lineages and one with hypocellularity in the erythroid lineage. Therefore, pSS patients with anemia may be associated with destruction of peripheral mature blood cells, impaired red cells production, and hematopoietic abnormalities due to an immune mechanism, although the concrete pathogenesis is still unclear.

No evidence for involvement of the toll-like receptor (TLR) 4 gene Asp299Gly and Thr399Ile polymorphisms in susceptibility to primary gouty arthritis

Previous studies demonstrated that toll-like receptor (TLR) 4 was involved in the development of autoinflammatory disease including gouty arthritis (GA). TLR4 functional gene Asp299Gly and Thr399Ile polymorphisms play a role in some autoinflammatory disease susceptibility. We undertook this study to analyze the association between the genetic polymorphisms within TLR4 gene and the susceptibility to GA in Chinese Han people. Two functional variants, Asp299Gly and Thr399Ile, in the TLR4 gene were genotyped using 5′ exonuclease TaqMan® technology from 218 male GA patients and 226 ethnically matched controls. None polymorphisms of Asp299Gly and Thr399Ile were detected in all GA cases and controls, which indicates that there is no evidence for involvement of the TLR4 gene Asp299Gly and Thr399Ile polymorphisms in susceptibility to primary GA in the Chinese Han population. Further studies with extended single nucleotide polymorphisms should be performed.

Innate immunity functional gene polymorphisms and gout susceptibility

Gout is a common autoinflammatory disease characterized with elevated serum urate and recurrent attacks of intra-articular crystal deposition of monosodium urate. Accumulating evidence has demonstrated that MSU crystal-induced inflammation is a paradigm of innate immunity and the TLRs, NALP3 inflammasome and IL1R pathways are involved in gout development. Innate immunity components containing TLR2, TLR4, CD14, NALP3, ASC, Caspase-1 and CARD-8 are essential in the development of gouty inflammation. Recent studies suggest that innate immunity component gene functional mutations contribute to the development of autoinflammatory diseases including hereditary periodic fever syndrome, arthritis as well as inflammatory bowel disease. Taking into account these genetic findings, we would like to propose a novel hypothesis that the gene functional mutations might make innate immunity components as attractive susceptibility candidates and genetic markers for gout. Further clinical genetic studies need to be performed to confirm the role of innate immunity in the etiology of gout.

Mice with miR-146a deficiency develop severe gouty arthritis via dysregulation of TRAF 6, IRAK 1 and NALP3 inflammasome.

BackgroundMicroRNAs (miRNAs) serve as important regulators of inflammatory and immune responses and are implicated in several immune disorders including gouty arthritis. The expression of miR-146a is upregulated in the peripheral blood mononuclear cells of patients with inter-critical gout when compared to normouricemic and hyperuricemic controls and those patients with acute gout flares. However, the role of miR-146a in the development of gout remains unknown. Here, we used miR-146a knockout (KO) mice to test miR-146a function in a monosodium urate (MSU)-induced gouty arthritis model.MethodsThe footpad or ankle joint of miR-146a KO and wild-type (WT) mice were injected with an MSU suspension to induce acute gouty arthritis. Bone marrow-derived macrophages (BMDMs) were stimulated with MSU and the gene expression of miR-146a; interleukin 1 beta (IL-1β); tumor necrosis factor-α (TNF-α); and the NACHT, LRR and PYD domains-containing protein 3 (NALP3) inflammasome was evaluated. TNF-α and IL-1β protein levels in BMDMs were assessed by fluorescence-activated cell sorting and western blot analyses. Gene and protein levels of TNF receptor-associated factor 6 (TRAF6) and IL-1 receptor-associated kinase (IRAK1), the targets of miR-146a, were also measured.ResultsSignificantly increased paw swelling and index and ankle joint swelling were observed in miR-146a KO mice compared to WT controls after MSU treatment. MiR-146a expression in BMDMs from WT mice was dramatically upregulated at 4 h following MSU stimulation. Additionally, the expression of IL-1β, TNF-α, and NALP3 was higher in BMDMs from miR-146a KO mice after exposure to MSU crystals compared to those from WT mice. Consistent with the observed gene expression, the IL-1β and TNF-α proteins were upregulated in miR-146a KO mice. Additionally quantitative RT-PCR and western blot demonstrated that TRAF6 and IRAK1 were dramatically upregulated in BMDMs from miR-146 KO mice compared to those from WT mice.ConclusionsCollectively, these observations suggest that miR-146a provides negative feedback regulation of gouty arthritis development and lack of miR-146a enhances gouty arthritis via upregulation of TRAK6, IRAK-1, and the NALP3 inflammasome function.

Estrogen Receptor β Signaling Induces Autophagy and Downregulates Glut9 Expression

Glut9 is highly expressed in the human kidney proximal convoluted tubular and plays a crucial role in the regulation of plasma urate levels. The gene effects were stronger among women. Our results show that 17-β-estradiol (E2) through ER (estrogen receptor) β downregulates Glut9 protein expression on human renal tubular epithelial cell line (HK2). Intriguingly, E2 does not affect the expression of Glut9 mRNA. ERβ is linked to PTEN, the PTEN gene negatively regulates the PI3K/AKT pathway, and the PI3K/AKT pathway inhibition may lead to autophagy. Further study indicates that ERβ may affect the expression of Glut9 though autophagy.

The ABCG2 gene Q141K polymorphism contributes to an increased risk of gout: A meta-analysis of 2185 cases

Abstract Objectives. Individual genetic association studies examining the relationship between the ABCG2 gene polymorphisms and gout have yielded inconsistent results. This study aims to evaluate the association between the ABCG2 gene variants and gout using meta-analysis. Materials and methods. Relevant studies were identified by searching databases extensively. The odds ratio (OR) was calculated using a random-effect or fixed-effect model. A Q statistic was used to evaluate homogeneity, and Eggers test and funnel plot were used to assess publication bias. Subgroup analyses on ethnicities and sex were also performed. Results. A total of 7 studies, including 2185 gout patients and 8028 controls from 5 countries or regions, were included and identified for the current meta-analysis. It was found that the A allele or AA genotype of the ABCG2 Q141K polymorphism (rs2231142) had an increased risk of gout in the general population (A allele, p < 0.00001 and AA genotype, p < 0.00001, respectively). On the contrary, CC homozygote played a protective role against the risk of gout (p < 0.00001). Similar results were found in subgroup analyses. However, there was a significant heterogeneity among studies. Conclusions. Existing evidence indicates that the Q141K polymorphism (rs2231142, the A allele and AA genotype) is associated with an increased risk of gout.