Impaired Function of CD5+CD19+CD1dhi B10 Cells on IgE Secretion in an Atopic Dermatitis-Like Mouse Model

Atopic dermatitis (AD) is a chronic inflammatory pruritic skin disease in which the pathogenic mechanism is complicated and not completely understood. Reports on the role of regulated cells in AD have recently evolved to regulate B cells, which may play a role in allergic inflammation as well. In the present study, we examined the frequency and regulatory function of CD5⁺CD19⁺CD1d^hi B10 cells in an AD-like mouse model. Our results showed that the percentage of CD5⁺CD19⁺CD1d^hi B10 cells increased while the frequency of IL-10-producing B cells in CD19⁺B cells decreased in the mice of AD group. Moreover, no difference in the percentage of B10pro+B10 cells was observed between the AD and control groups. Strikingly, B10 cells from control mice effectively inhibited IgE secretion, whereas the suppressive function of B10 cells from the AD mice was significantly decreased, which was similar to that observed in the group without B10. Altogether, these results suggest that the number of IL-10-producing B cells decreased in the AD group and these cells showed a defective regulatory function on IgE secretion.     

Pathway-Based Genome-Wide Association Studies for Plasma Triglycerides in Obese Females and Normal-Weight Controls

Pathway-based analysis as an alternative approach can provide complementary information to single-marker genome-wide association studies (GWASs), which always ignore the epistasis and does not have sufficient power to find rare variants. In this study, using genotypes from a genome-wide association study (GWAS), pathway-based association studies were carried out by a modified Gene Set Enrichment Algorithm (GSEA) method (GenGen) for triglyceride in 1028 unrelated European-American extremely obese females (BMI≥35kg/m²) and normal-weight controls (BMI<25kg/m²), and another pathway association analysis (ICSNPathway) was also used to verify the GenGen result in the same data. The GO0009110 pathway (vitamin anabolism) was among the strongest associations with triglyceride (empirical P<0.001); the result remained significant after FDR correction (P = 0.022). MMAB, an obesity-related locus, included in this pathway. The ABCG1 and BCL6 gene was found in several triglyceride-related pathways (empirical P<0.05), which were also replicated by ICSNPathway (empirical P<0.05, FDR<0.05). We also performed single-marked GWAS using PLINK for TG levels (log-transformed). Significant associations were found between ASTN2 gene SNPs and plasma triglyceride levels (rs7035794, P = 2.24×10⁻¹⁰). Our study suggested that vitamin anabolism pathway, BCL6 gene pathways and ASTN2 gene may contribute to the genetic variation of plasma triglyceride concentrations.     

结核分枝杆菌Rv1886c的原核表达及其免疫生物学特性

摘要:【目的】Rv1886c基因编码的Ag85B是结核分枝杆菌(Mycobacterium tuberculosis,M．tb)感染早期的分泌蛋白,本研究对其所诱导的免疫应答特性进行了探索。【方法】对Ag85B进行原核表达和鉴定,并通过夹心ELISA、间接ELISA及ELISPOT方法测定其诱导的细胞免疫和体液免疫应答水平。【结果】SDS-PAGE及Western blot鉴定结果表明,以包涵体形式表达的Ag85B蛋白,经变性、复性后能与结核病人的抗血清及免疫重组李斯特菌LM-Ag85B的小鼠抗血清发生特异性反应,表明His-Ag85B融合蛋白具有较好的免疫活性。将纯化的Ag85B 蛋白皮下免疫C57BL/6小鼠,夹心ELISA的测定结果表明,Ag85B蛋白免疫组诱导小鼠产生的特异性IFN-γ水平显著高于IL-4的水平(P＜0.001),呈现Th1型细胞免疫应答趋势;以结核菌素PPD作为包被抗原,通过间接ELISA测定的血清抗体效价达到1∶6400,表明Ag85B也能诱导有效的体液免疫应答。此外,以尾静脉途径初次免疫小鼠42天时,ELISPOT测定结果显示,结核分枝杆菌H37Rv诱导小鼠产生Ag85B240－259特异性的IFN-γ水平极显著高于卡介苗(BCG)免疫组(P＜0.001)。【结论】Ag85B蛋白能激发小鼠产生较强的Th1型细胞免疫应答和较好的体液免疫应答;BCG单次免疫后诱导小鼠产生的Ag85B特异的细胞免疫应答水平较低。本研究为揭示结核分枝杆菌的致病机理、新型疫苗的研制和早期诊断试剂的开发奠定了基础。     

炭疽芽胞杆菌中CRISPR位点

【目的】考察炭疽芽胞杆菌中规律成簇的间隔短回文序列(Clustered regularly interspaced short palindromic repeats,CRISPR)位点多态性情况及基于CRISPR位点多态性的分子分型方法是否在炭疽芽胞杆菌分型中适用。【方法】下载NCBI数据库中6株炭疽芽胞杆菌基因组并截取其中CRISPR位点片段序列。根据炭疽芽胞杆菌内CRISPR位点信息,设计相关引物,以193株炭疽芽胞杆菌基因组为模板PCR扩增CRISPR位点片段,测序。本地Blast比对截取序列及测序结果,查看CRISPR位点在炭疽芽胞杆菌中的多态性情况,并比较炭疽芽胞杆菌与蜡样芽胞杆菌和苏云金芽胞杆菌内CRISPR位点情况。【结果】炭疽芽胞杆菌内CRISPR位点不存在多态性。【结论】基于CRISPR位点多态性的分子分型方法不适用于炭疽芽胞杆菌分型,但可以用于区分炭疽芽胞杆菌与蜡样芽胞杆菌和苏云金芽胞杆菌。     

Histone deacetylase1 promotes TGF-β1-mediated early chondrogenesis through down-regulating canonical Wnt signaling

Cartilage formation during both embryonic development and bone repairing processes involves mesenchymal stem cells (MSCs) differentiation. Wnt/β-catenin signaling pathway inhibits early chondrogenesis and is down-regulated during Transforming growth factor-β1 (TGF-β1)-induced chondrogenesis. However, the regulatory molecules that participate in the process is unknown. This study was designed to investigate the underlying mechanisms that down-regulate Wnt/β-catenin pathway during chondrogenesis. TGF-β1-induced micromass cultures of C3H10T1/2 were used as chondrocyte differentiation model. Gene expression profile was detected by realtime-PCR. Regulatory role of HDAC1 on β-catenin was investigated by luciferase assay, chromatin immunoprecipitation (ChIP) assay, co-immunoprecipitation (Co-IP) assay and in vitro ubiquitination assay. In this study, we showed that HDAC1 was induced and suppressed β-catenin gene expression through direct binding to its promoter. Besides, HDAC1 could also interact with deacetylate β-catenin protein through its deacetylase domain, which causes degradation of β-catenin. Our results indicate that HDAC1 plays an important role in chondrogenesis and may represent a therapeutic target for modulation of cartilage development.     

A Highlights from MBoC Selection: Drosophila Histone Deacetylase 6 Protects Dopaminergic Neurons against α-Synuclein Toxicity by Promoting Inclusion Formation

Parkinson''s disease (PD) is associated with progressive degeneration of dopaminergic (DA) neurons. We report for the first time that the Drosophila histone deacetylase 6 (dHDAC6) plays a critical role in the protection of DA neurons and the formation of α-synuclein inclusions by using a Drosophila PD model constructed by ectopic expression of human α-synuclein. Depletion of dHDAC6 significantly enhances the effects caused by ectopic expression of α-synuclein, namely, loss of DA neurons, retinal degeneration, and locomotor dysfunction. Expression of α-synuclein in the DA neurons leads to fewer inclusions in the brains of dHDAC6 mutant flies than in wild-type flies. Conversely, overexpression of dHDAC6 is able to suppress the α-synuclein–induced DA neuron loss and retinal degeneration and promote inclusion formation. Furthermore, mutation of dHDAC6 reinforces the accumulation of oligomers that are suggested to be a toxic form of α-synuclein. We propose that α-synuclein inclusion formation in the presence of dHDAC6 protects DA neurons from being damaged by oligomers, which may uncover a common mechanism for synucleinopathies.     

Evaluation and Spatial Diffusion of Health Risk of Persistent Organic Pollutants (POPs) in Soils Surrounding Chemical Industrial Parks in China

A case study of the cancer risk to humans posed by persistent organic pollutants (POPs) in an industrial area of China, which has a long history of contamination from many sources, is presented. Relatively great concentrations of POPs around the chemical industrial parks have the potential to be chronically carcinogenic to local people. Sixteen individual PAHs listed for priory control by the U.S. Environmental Protection Agency (USEPA), metabolites of DDTs, and isomers of HCHs were measured in soils and a human health risk assessment was conducted by use of USEPA exposure models for children and adults, respectively. Geostatistical methods were used to simulate the spatial diffusion of potential carcinogenic risk, and non-parametric Mann-Whitney U and Kruskal-Wallis tests were employed to analyze the impact of point sources on the surrounding area. The mean value of the sum of Excess Lifetime Cancer Risk (∑ELCR) exceeded the generally acceptable risk level of 1.0E-06 recommended by the USEPA for carcinogenic chemicals. The maximum ∑ELCR was 2.9E-04 for children, which was observed inside the chemical industrial parks. Contamination at the chemical industrial parks caused significant spatial diffusion of ELCR values caused by PAHs, DDT, and HCH.     

Enzymatic synthesis of theanine from glutamic acid γ-methyl ester and ethylamine by immobilized Escherichia coli cells with γ-glutamyltranspeptidase activity

Theanine (γ-glutamylethylamide) is the main amino acid component in green tea. The demand for theanine in the food and pharmaceutical industries continues to increase because of its special flavour and multiple physiological effects. In this research, an improved method for enzymatic theanine synthesis is reported. An economical substrate, glutamic acid γ-methyl ester, was used in the synthesis catalyzed by immobilized Escherichia coli cells with γ-glutamyltranspeptidase (GGT) activity. The results show that GGT activity with glutamic acid γ-methyl ester as substrate was about 1.2-folds higher than that with glutamine as substrate. Reaction conditions were optimized by using 300 mmol/l glutamic acid γ-methyl ester, 3,000 mmol/l ethylamine, and 0.1 g/ml of immobilized GGT cells at pH 10 and 50°C. Under these conditions, the immobilized cells were continuously used ten times, yielding an average glutamic acid γ-methyl ester to theanine conversion rate of 69.3%. Bead activity did not change significantly the first six times they were used, and the average conversion rate during the first six instances was 87.2%. The immobilized cells exhibited favourable operational stability.