NALP3炎性体与非感染性炎症疾病

在机体非感染性炎症疾病过程中,caspase-1的活化引起IL-1β、IL-18、IL-33等促炎细胞因子的分泌是一个重要的过程.而一个被称为NALP3炎性体的多蛋白复合物在caspase-1的活化过程中起到了重要的调节作用.各种外源或内源的刺激可通过不同的信号通路激活NALP3炎性体来活化caspase-1.本文就NALP3炎性体的结构和分布、活化和信号通路及对2型糖尿病、痛风、阿尔兹海默病和肾脏疾病等非感染性炎症疾病的近期研究作一综述.     

沙眼衣原体感染诱导小鼠生殖道局部促炎性细胞因子的表达情况

建立小鼠生殖道沙眼衣原体感染模型,观察小鼠生殖道局部促炎性细胞因子的表达。将小鼠生物型沙眼衣原体C. muridarum 1＆#215;104 IFU阴道接种于C57B6背景雌性小鼠,取感染后阴道拭子做沙眼衣原体培养,计算IFU,监测小鼠感染和病原体清除情况;80 d后处死小鼠,检测子宫输卵管病理改变;ELISA检测感染过程中小鼠生殖道促炎性细胞因子IL-1α、IL-6、MIP-2和TNF-α产生情况。小鼠感染在第3至第15天维持较高水平,然后病原体被逐渐清除,整个病程约3~5周;病理检测显示子宫输卵有严重炎症、管腔扩张积水,狭窄等;于感染后第3天检测到局部IL-1α、IL-6、MIP-2分泌,第7天达高峰,然后逐渐下降至正常水平（ IL-6于11 d恢复正常,IL-1α和 MIP-2于15 d恢复正常）。 TNF-α仅在第7天检测到高水平表达。相对于TNF-α和IL-6,IL-1α和MIP-2维持时间较长。成功建立沙眼衣原体感染小鼠生殖道模型,沙眼衣原体急性感染可诱导小鼠生殖道局部分泌IL-1α、IL-6、MIP-2和TNF-α。     

CT358蛋白在沙眼衣原体感染细胞中的定位及特性分析

确定沙眼衣原体CT358蛋白在衣原体感染细胞中的位置并初步鉴定其生物学功能．采用PCR方法从D型沙眼衣原体的基因组中扩增CT358基因,并克隆入pGEX和pDSRedC1表达载体中．将重组质粒pGEX-CT358转化到XL1-blue宿主菌,并诱导表达融合蛋白GST-CT358．纯化后的CT358融合蛋白免疫小鼠制备抗体,应用间接免疫荧光技术对CT358蛋白在衣原体感染细胞内的定位及表达模式进行分析．同时,pDSRedC1-CT358重组质粒瞬时转染HeLa细胞,观察CT358蛋白对衣原体感染的影响．实验结果证明CT358蛋白为沙眼衣原体包涵体膜蛋白．该蛋白质在衣原体感染12 h后就表达定位于包涵体膜上,直至持续到整个感染周期,转基因在胞浆表达的CT358融合蛋白不影响其后的衣原体感染．该研究为深入研究衣原体与宿主细胞间相互作用提供了新的线索,并可为衣原体性的治疗、预防提供新方向．     

沙眼衣原体质粒蛋白pgp3的研究进展

沙眼衣原体分泌性蛋白在沙眼衣原体致病过程中起重要作用,质粒编码的蛋白pgp3(即pORF5)是迄今为止发现的唯一由沙眼衣原体质粒编码的分泌性蛋白。pgp3在沙眼衣原体感染早期即可表达,在感染人群中具有很强的免疫原性,且人抗体对pgp3的识别具有高度的结构依赖性,对该蛋白的研究将有助于进一步了解衣原体质粒编码蛋白的作用及衣原体致病机制,以寻找更好的衣原体诊断方法和防治措施。本文就沙眼衣原体质粒编码蛋白pgp3的生物学性质及其致病机制作一简要综述。     

肥大细胞在大鼠输卵管急性沙眼衣原体感染中的作用

目的　为研究肥大细胞在大鼠输卵管急性沙眼衣原体 (Chlamydialtrachomatis,CT)感染中的作用。方法　选择成年雌性SD大鼠 6 0只 ,通过手术从一侧卵巢囊接种沙眼衣原体D型株 ,对照组接种 2 -SPA缓冲液。分别于感染后第 1/ 2d、第 7d、第 14d将大鼠处死 ,取手术侧的输卵管常规固定、脱水、包埋。结果　S -P法显示 :输卵管局部的CD4 + T细胞和血管内皮细胞粘附分子 (VCAM - 1)的表达均较对照组明显增强 (P <0 0 1)。改良的甲苯胺蓝染色法显示 :感染组肥大细胞较对照组数量有显著性增高 (P <0 0 5 ) ,并且其变化趋势与CD4 + T细胞和VCAM - 1表达的变化趋势一致。结论　可以推测 ,沙眼衣原体感染引起急性输卵管炎时 ,肥大细胞通过促进炎症局部小静脉内皮细胞上VCAM -1的表达 ,诱导CD4 + T细胞的浸润 ;然后分泌IL - 4等细胞因子促进CD4 + T细胞向TH2 细胞方向转化 ,不利于机体清除沙眼衣原体 ,从而使发生局部输卵管病理损伤的可能性增加。     

假定蛋白CT440在沙眼衣原体感染细胞中的定位研究

包涵体膜蛋白在沙眼衣原体致病过程中发挥重要的作用.为确定假定蛋白CT440在沙眼衣原体感染细胞中的定位及特征,本研究采用PCR方法从D型沙眼衣原体的基因组中扩增Ct440基因,克隆入pGEX-6p原核表达载体构建pGEX-6p/Ct440原核表达重组体,重组体转化到XL1-blue大肠杆菌,IPTG诱导表达融合蛋白GST-CT440.纯化后的CT440融合蛋白免疫小鼠制备抗体,间接免疫荧光(IFA)和Western blot测定抗体的特异性.特异性抗体用于分析CT440蛋白在衣原体感染细胞内的定位、表达时相特征及其对衣原体感染的影响.结果表明,CT440蛋白定位于沙眼衣原体包涵体膜上,为沙眼衣原体包涵体膜蛋白;该蛋白在衣原体感染12h后开始表达,直至持续到整个感染周期;转基因在胞浆表达的CT440融合蛋白不影响其后的衣原体感染.本实验为深入研究衣原体与宿主细胞间的相互作用,阐明衣原体致病机制提供了重要的实验依据.     

沙眼衣原体质粒蛋白研究进展

沙眼衣原体除含有高度保守的基因组外,也含一个7．5kb的隐蔽性质粒,隐蔽性质粒具有8个开放阅读（ORF1-8）,编码8种质粒蛋白pgpl-8。质粒蛋白在沙眼衣原体致病过程中发挥重要的作用,尤其是新近发现沙眼衣原体的唯一一种分泌到胞浆中的分泌性蛋白pgp3和对毒力相关基因具有转录调节功能的pgp4。对就沙衣原体的质粒蛋白研究现状进行了综述。     

沙眼衣原体感染分子流行病学进展

沙眼衣原体是最常见的性传播疾病（STD）的病原体之一,严格寄生细胞内生长,常见侵袭眼结膜及泌尿生殖道黏膜的单层柱状上皮细胞,可导致多个器官炎症性改变,并与肿瘤的发生有关。而不同的基因分型具有不同的组织嗜性和致病表现,使得沙眼衣原体的分子流行病学与临床的关系逐渐成为热点。现就近年来的研究进行一系统回顾。     

γ干扰素与自噬在抗沙眼衣原体感染中的作用

沙眼衣原体(Chlamydia trachomatis,Ct)具有广泛致病谱,是引起感染性致盲的首要病因,也是性传播疾病的主要病原体。γ干扰素在抗Ct感染中起重要作用。自噬是维持细胞内环境自稳的一种自我保护机制,与γ干扰素介导的抗Ct感染作用关系密切。就γ干扰素与自噬抗Ct感染的作用进行综述。     

Thioredoxin-interacting protein mediates NALP3 inflammasome activation in podocytes during diabetic nephropathy

Numerous studies have shown that the NALP3 inflammasome plays an important role in various immune and inflammatory diseases. However, whether the NALP3 inflammasome is involved in the pathogenesis of diabetic nephropathy (DN) is unclear. In our study, we confirmed that high glucose (HG) concentrations induced NALP3 inflammasome activation both in vivo and in vitro. Blocking NALP3 inflammasome activation by NALP3/ASC shRNA and caspase-1 inhibition prevented IL-1β production and eventually attenuated podocyte and glomerular injury under HG conditions. We also found that thioredoxin (TRX)-interacting protein (TXNIP), which is a pro-oxidative stress and pro-inflammatory factor, activated NALP3 inflammasome by interacting with NALP3 in HG-exposed podocytes. Knocking down TXNIP impeded NALP3 inflammasome activation and alleviated podocyte injury caused by HG. In summary, the NALP3 inflammasome mediates podocyte and glomerular injury in DN, moreover, TXNIP participates in the formation and activation of the NALP3 inflammasome in podocytes during DN, which represents a novel mechanism of podocyte and glomerular injury under diabetic conditions.     

Sodium overload and water influx activate the NALP3 inflammasome

The NALP3 inflammasome is activated by low intracellular potassium concentrations [K(+)](i), leading to the secretion of the proinflammatory cytokine IL-1β. However, the mechanism of [K(+)](i) lowering after phagocytosis of monosodium urate crystals is still elusive. Here, we propose that endosomes containing monosodium urate crystals fuse with acidic lysosomes. The low pH in the phagolysosome causes a massive release of sodium and raises the intracellular osmolarity. This process is balanced by passive water influx through aquaporins leading to cell swelling. This process dilutes [K(+)](i) to values below the threshold of 90 mm known to activate NALP3 inflammasomes without net loss of cytoplasmic potassium ions. In vitro, the inhibitors of lysosomal acidification (ammonium chloride, chloroquine) and of aquaporins (mercury chloride, phloretin) all significantly decreased the production of IL-1β. In vivo, only the pharmacological inhibitor of lysosome acidification chloroquine could be used which again significantly reduced the IL-1β production. As a translational aspect one may consider the use of chloroquine for the anti-inflammatory treatment of refractory gout.     

沙眼衣原体疫苗候选抗原研究进展

沙眼衣原体(CT)是引起感染性致盲的首要病因,也是引起性传播疾病的主要病原体。CT感染缺乏明显的临床症状,临床上容易被忽视而引起严重的疾病,故疫苗是预防CT生殖道感染经济有效的措施之一。综述了CT疫苗候选抗原的结构特点,免疫保护作用及其在预防CT感染性疾病的应用前景。     

Lipopolysaccharide Primes the NALP3 Inflammasome by Inhibiting Its Ubiquitination and Degradation Mediated by the SCFFBXL2 E3 Ligase

The inflammasome is a multiprotein complex that augments the proinflammatory response by increasing the generation and cellular release of key cytokines. Specifically, the NALP3 inflammasome requires two-step signaling, priming and activation, to be functional to release the proinflammatory cytokines IL-1β and IL-18. The priming process, through unknown mechanisms, increases the protein levels of NALP3 and pro-IL-1β in cells. Here we show that LPS increases the NALP3 protein lifespan without significantly altering steady-state mRNA in human cells. LPS exposure reduces the ubiquitin-mediated proteasomal processing of NALP3 by inducing levels of an E3 ligase component, FBXO3, which targets FBXL2. The latter is an endogenous mediator of NALP3 degradation. FBXL2 recognizes Trp-73 within NALP3 for interaction and targets Lys-689 within NALP3 for ubiquitin ligation and degradation. A unique small molecule inhibitor of FBXO3 restores FBXL2 levels, resulting in decreased NALP3 protein levels in cells and, thereby, reducing the release of IL-1β and IL-18 in human inflammatory cells after NALP3 activation. Our findings uncover NALP3 as a molecular target for FBXL2 and suggest that therapeutic targeting of the inflammasome may serve as a platform for preclinical intervention.     

NLRP3 inflammasome negatively regulates podocyte autophagy in diabetic nephropathy

Inflammasome mechanisms are recognized as a key pathophysiology of diabetic nephropathy (DN). The nucleotide-oligomerization domain-like receptor 3 (NLRP3) inflammasome has attracted the most attention. Autophagy as a conserved intracellular catabolic pathway plays essential roles in the maintenance of podocytes. Although autophagy was involved in preventing excessive inflammatory responses in kidney diseases, a clear understanding of the regulation of NLRP3 inflammasome on autophagy in glomerular damage in DN is still lacking. In this study, we focused on the effect of the activation of NLRP3 inflammasome on the suppression of podocyte autophagy and aimed to investigate the role of autophagy in podocyte injury in DN. Podocyte autophagy has been confirmed to be inhibited in high-fat diet/streptozotocin (HFD/STZ)-induced DN mice, and NLRP3 has been found to be upregulated in both mice and human DN biopsies and in vitro. Activation of NLRP3 inflammasome exacerbated podocyte autophagy and reduced podocyte nephrin expression, while silencing of NLRP3 efficiently restored podocyte autophagy and ameliorated podocyte injury induced by high glucose. The results showed that NLRP3 was a negative regulator of autophagy and suggested that restoration of podocyte autophagy by inactivation of NLRP3 under high glucose could reduce podocyte injury. Proper modification of autophagy and inflammasome has the potential to benefit the kidney in DN.     

Comparative PCR-based restriction fragment length polymorphism analysis of the plasmid gene orf3 of Chlamydia trachomatis and Chlamydia psittaci

The BfaI digestion of PCR-based restriction fragment length polymorphism analysis of the plasmid orf3 of Chlamydia trachomatis and Chlamydia psittaci provided evidence for two distinct restriction patterns, respectively. The nucleotide sequences of orf3 genes confirmed these differences. Serum antibodies against recombinant C. psittaci protein (pgp3) encoded by orf3 were detected both in pigeons with C. psittaci infection and in a human patient with psittacosis.     

Reversibility of heat shock in Chlamydia trachomatis

The heat shock effect on chlamydia development was studied. We report here that the reversibility of the heat shock response did not depend on the stage of chlamydial morphogenesis at which transfer to high temperature occurred, and the infectivity of the particles produced was not affected significantly, so long as the heat shock exposure was not prolonged. Exposure to heat shock for more than 9 h resulted in stagnation of the growth cycle, appearance of aberrant reticulate body particles and loss of infectivity. SDS-PAGE analysis of proteins synthesized under prolonged heat shock showed increased relative abundance of heat shock proteins in common with other procaryotic organisms.     

Trifluoperazine inhibits the infectivity of Chlamydia trachomatis for McCoy cells

Abstract Trifluoperazine (TFP), an inhibitor of the Ca²⁺-binding protein calmodulin, was used to study the infectivity of Chlamydia trachomatis for McCoy cells. TFP inhibited the number of chlamydial inclusions and the chlamydia-dependent amino acid incorporation when added within 9 h after inoculation with chlamydiae. However, TFP did not affect the attachment of chlamydiae to the cells or the protease-removable fraction of cell-bound chlamydiae.
These results suggest that an early step in the intracellular development of chlamydiae, partly coinciding with the elementary body-reticulate body conversion, is sensitive to TFP and that clathrin coats are not crucial in the ingestion of chlamydiae by McCoy cells.     

Primary and secondary immune responses of mucosal and peripheral lymphocytes during Chlamydia trachomatis infection

Chlamydia trachomatis infection is followed by the development of antigen-specific cell-mediated immunity, which is detectable as a positive lymphocyte proliferation response to the chlamydial major outer membrane protein (MOMP) antigen. To date, however, there have been no studies on the mucosal immune responses to chlamydial antigens. This study aimed to study the primary and secondary immune responses of cervical lymphocytes in response to the chlamydial antigen. Median proliferative responses were found to be significantly (P<0.05) higher in patients with chlamydial infections than in controls. The chlamydial MOMP induced significantly higher IL-6 and IL-10 and lower interferon-gamma (IFN-gamma) secretion in cervical lymphocytes of Chlamydia-positive women, resulting in a T helper 2 response. On stimulation of peripheral blood mononuclear cells (PBMC) obtained from Chlamydia-positive women with the chlamydial antigen, the median levels of IL-10, IL-12 and IFN-gamma were higher than in controls, but the differences were not significant. Our study suggests that the mucosal immune responses towards Chlamydia trachomatis are different from those of PBMCs and are more helpful in understanding the cytokine responses in the female genital tract during chlamydial infection.