树突状细胞C型凝集素在自然流产中的表达研究

目的通过检测早期自然流产患者子宫蜕膜组织中树突状细胞C型凝集素（DC-SIGN）的表达,探讨其在自然流产发生中的可能机制。方法采用免疫荧光染色法及实时荧光定量PCR（RT-PCR）技术检测DC-SIGN在蜕膜组织中的表达,比较两组间表达情况及分布差异。结果 1.通过免疫荧光染色技术检测显示：妊娠期子宫蜕膜组织均表达DC-SIGN,主要分布于细胞膜上,自然流产组中DC-SIGN＋DC表达明显低于对照组（46.20±2.40 vs 78.21±0.28,P〈0.01）。2.RT-PCR结果显示：自然流产组明显低于对照组,患者蜕膜组织中DC-SIGN mRNA相对表达量（0.0032370±0.00124 vs0.0076412±0.0040,P〈0.05）。结论树突状细胞（DC）在母胎免疫耐受机制中起着重要的作用,蜕膜组织DC-SIGN的表达量降低可能导致早期自然流产的发生。     

DC-SIGN polymorphisms are associated to type 1 diabetes mellitus

Type I diabetes mellitus (T1DM) is an autoimmune disorder featured by raised glucoses levels. It has been hypothesised that raised glucose levels in T1DM might be recognised as PAMPs, leading to immune response by overloading the cell receptors for pathogens recognition. DC-SIGN is a transmembrane protein, present in dendritic cells (DC) and macrophages: it has an important role in inflammatory response and T cells activation. Notably, DC-SIGN activation and triggering of the immune response depend on the type of ligand, which may lead to a pro or anti-inflammatory pathway. In our association study, we analysed the SNPs rs4804803 (−336 A>G) and rs735239 (−871 A>G), both at DC-SIGN promoter region, in 210 T1DM patients and 157 healthy controls, also looking for a correlation with the age of onset of the disease. We found that the allele G and genotypes G/G and A/G of SNP-871 (rs735239), as well as the alleles G-G (rs735239-rs4804803) and genotypes combined AA-GG (rs735239-rs4804803) were associated with protection of T1DM development. We did not find association between these variations with the age of onset of the disease and the presence of other autoimmune disorders. Our results suggest that SNPs in DC-SIGN promoter region can be associated to protection for T1DM in the Northeast Brazilian population.     

Is asthma a protective factor for dengue fever? In vitro experiment and nationwide population-based cohort analysis

BackgroundDengue fever (DF) is the most rapidly spreading mosquito-borne viral disease. Practical vaccines or specific therapeutics are still expected. Environmental factors and genetic factors affect the susceptibility of Dengue virus (DV) infection. Asthma is a common allergic disease, with house dust mites (HDMs) being the most important allergens. Asthmatic patients are susceptible to several microorganism infections.MethodsA nationwide population-based cohort analysis was designed to assess whether to determine whether asthma can be a risk factor for DF.ResultsUnexpectedly, our data from a nationwide population-based cohort revealed asthmatic patients are at a decreased risk of DF. Compared to patients without asthma, the hazard ratio (HR) for DF in patients with asthma was 0.166 (95% CI: 0.118–0.233) after adjustment for possible confounding factors. In the age stratification, the adjusted HR for DF in young adult patients with asthma was 0.063. Dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) of dendritic cells (DCs) is an important entry for DV. Through another in vitro experiment, we found that HDM can diminish surface expression of DC-SIGN in monocyte-derived DCs and further decrease the cellular entry of DV.ConclusionsDecreased DC-SIGN expression in DCs of allergic asthmatic patient may be one of many factors for them to be protected against DF. This could implicate the potential for DC-SIGN modulation as a candidate target for designing therapeutic strategies for DF.     

肝炎病毒利用DC-SIGN逃逸机体免疫作用

DC-SIGN是DC表面识别多种病原微生物的受体.一方面,DC借助DC-SIGN对固有免疫及适应性免疫发挥免疫调节作用;另一方面,DC-SIGN又成为某些病原微生物如肝炎病毒借以逃逸机体免疫防御功能的靶分子.我们就DC-SIGN的结构及功能、与病毒的相互作用等方面进行阐述.     

Surfactant protein D inhibits mite-induced alveolar macrophage and dendritic cell activations through TLR signalling and DC-SIGN expression

Background Surfactant protein D (SP‐D), a secreted pattern recognition molecule associated with pulmonary innate immunity, has been shown to mediate the clearance of pathogens in multiple ways. However, how SP‐D interacts with alveolar macrophages (AMs) and dendritic cells (DCs) during allergen exposure remains unclear. Objective This study was performed to characterize the immunomodulatory effects of SP‐D on mite allergen (Dermatophagoides pteronyssinus, Der p)‐induced inflammatory signalling in AMs and DCs. Methods Murine AM, alveolar macrophage cell line derived from BALB/c mice (MH‐S cells), and human monocyte‐derived dendritic cells (MDDC) were used as model systems. The production of nitric oxide (NO) and TNF‐α, expression of surface Toll‐like receptors (TLRs), and expression of the C‐type lectin receptor known as dendritic cell (DC)‐specific ICAM‐grabbing non‐integrin (DC‐SIGN) were measured as a function of pretreatment with SP‐D and subsequent exposure to Der p. Der p‐dependent cellular activations that were modified by SP‐D in these model systems were then identified. Results Pretreatment of MH‐S cells with SP‐D reduced Der p‐dependent production of NO, TNF‐α, and the downstream activations of IL‐1 receptor‐associated kinase, mitogen activated protein kinase (MAPK) kinase, and nuclear factor‐κB. SP‐D interacted with CD14 such that CD14 binding to Der p was inhibited and Der p‐induced signalling via TLRs was blocked. DC‐SIGN expression was suppressed by Der p in MH‐S and MDDC; this down‐regulation of DC‐SIGN expression was prevented by pretreatment with SP‐D. Conclusions These results indicated that the inhibition of Der p‐induced activation of MH‐S and MDDC by SP‐D is mediated through suppression of the CD14/TLR signalling pathway and maintenance of DC‐SIGN expression, which may protect allergen‐induced airway inflammation. Cite this as: C‐F Liu, M. Rivere, H‐J Huang, G. Puzo and J‐Y Wang, Clinical & Experimental Allergy, 2010 (40) 111–122.     

DC SIGN与微生物感染的研究进展

树突状细胞（dendriti ccell，DC）是机体内专职的抗原提呈细胞（antigen presenting cell，APC），免疫应答的始动者，处于免疫反应的控制位置。DC特异性细胞间黏附分子-3结合非整合素因子（dendritic cell-specific intercellular adhension molecule-3-grabbing nonintegrin，DC-SIGN，CD209）是DC表面特异性的识别受体与黏附受体。     

Role of DC-SIGN and L-SIGN receptors in HIV-1 vertical transmission

The innate immune system acts in the first line of host defense against pathogens. One of the mechanisms used involves the early recognition and uptake of microbes by host professional phagocytes, through pattern recognition receptors (PRRs). These PRRs bind to conserved microbial ligands expressed by pathogens and initiate both innate and adaptative immune responses. Some PRRs located on the surface of dendritic cells (DCs) and other cells seem to play an important role in human immunodeficiency virus type 1 (HIV-1) transmission. Dendritic cell-specific intercellular adhesion molecule-3 grabbing non-integrin, CD209 (DC-SIGN) and its homolog, DC-SIGN-related (DC-SIGNR or L-SIGN) receptors are PPRs able to bind the HIV-1 gp120 envelope protein and, because alterations in their expression patterns also occur, they might play a role in both horizontal and vertical transmission as well as in disseminating the virus within the host. This review aims to explore the involvement of the DC-SIGN and L-SIGN receptors in HIV-1 transmission from mother to child.     

人DC-SIGN全长编码区基因的克隆及其胞外段的原核表达

目的:克隆人DC-SIGN全长编码区基因, 获得其胞外段的原核表达产物.方法:采用RT-PCR方法, 从健康产妇胎盘中克隆DC-SIGN全长cDNA, 扩增其胞外段基因并构建pET41a-sDC-SIGN重组表达质粒, 在大肠杆菌BL21(DE3)中表达, 以SDS-PAGE和Western blot鉴定表达产物.结果:从健康产妇胎盘总RNA中, 扩增获得约1 300 bp的DNA片段, 克隆至pGM-T载体获得重组质粒pGM-DC-SIGN.从pGM-DC-SIGN扩增DC-SIGN的胞外段基因, 构建重组表达质粒pET- 41a-sDC-SIGN;纯化表达产物sDC-SIGN-GST, 鉴定其相对分子质量( M r)为66 000, Western blot证明其可与抗DC-SIGN抗体特异性结合.结论:成功克隆DC-SIGN全长编码区基因, 并在大肠杆菌中成功表达其胞外段融合蛋白sDC-SIGN-GST, 为进一步研究DC-SIGN的功能奠定了基础.     

树突状细胞在肾小管间质炎症病变中的作用及抗黏附干预调节的研究

目的 探讨树突状细胞(DC)在肾小管间质炎症损伤中的作用，以及抗P-选择素功能域单抗(PsL-EGFmAb)对DC浸润及体外成熟与功能的干预调节。 方法 (1)建立大鼠单侧输尿管梗阻(UUO)模型。分别采用免疫组化和免疫双染与图像分析，观察P-选择素及CD1a+CD80+DC在肾组织表达和分布变化。(2)从脐血CD34+造血干细胞中诱导扩增DC，并于成熟过程中采用流式细胞仪分析细胞表面分子表达；RT-PCR检测细胞NF-κB P50、P65 mRNA表达；混合淋巴细胞反应(MLR)检测DC对T细胞刺激能力；以及ELISA测定MLR上清液IL-12 p70分泌含量。 结果 (1)与假手术组比较，UUO大鼠从第1天起，随着P-选择素以肾小管上皮细胞为主的小管间质表达，CD1a+CD80+DC以肾间质为主浸润；至第7天P-选择素上调且CD1a+CD80+DC显著聚集，两者明显相关且与肾小管间质病变程度显著相关。经PsL-EGFmAb处理后，大鼠肾组织P-选择素表达下调，CD1a+CD80+DC浸润减少，且肾小管间质损害程度减轻。(2)经TNF-α刺激炎性状态下，培养人DC成熟过程中基本不表达或低表达P-选择素，但持续高表达与P-选择素同属C型凝集素的DC-SIGN。经PsL-EGFmAb处理后，可明显抑制DC-SIGN及细胞内NF-κB基因表达，并相应抑制DC黏附共刺激分子表达、IL-12分泌及刺激T细胞增殖能力。 结论 DC也是肾小管间质炎症病变启动因素，针对P-选择素功能域的单抗对其浸润具抑制作用。此外，该单抗对人DC成熟与功能有调节效应，提示与抑制作为DC模式识别及黏附受体的DC-SIGN有关，并可能通过影响NF-κB途径起作用。