Dectin-1介导香菇多糖诱导人单核细胞系THP-1细胞产生IL-12的研究

目的探讨香菇多糖能否依赖Dectin-1介导而诱导人单核细胞系THP-1细胞产生IL-12。方法香菇多糖作用THP-1细胞后,实时荧光定量RT-PCR检测Dectin-1、IL-12p35和IL-12p40的mRNA表达水平;ELISA法检测THP-1细胞分泌IL-12的含量;以Dectin-1抑制剂昆布多糖预处理THP-1细胞,比较香菇多糖诱导产生IL-12的变化。结果香菇多糖可上调THP-1细胞表达Dectin-1的mRNA水平;能上调THP-1细胞IL-12p35和IL-12p40的mRNA表达和IL-12分泌;昆布多糖可明显抑制香菇多糖诱导THP-1细胞分泌IL-12。结论 Dectin-1能介导香菇多糖诱导人单核细胞系THP-1细胞产生IL-12。     

STAT3抑制剂Stattic激活ERK通路诱导THP-1细胞IL-8的产生及细胞凋亡

目的观察信号转导子与转录激活子3(STAT3)抑制剂Stattic对THP-1细胞产生白细胞介素8(IL-8)和细胞凋亡的影响,并探讨其机制。方法采用(0、 1、 5、 10、 15、 20)μmol/L Stattic处理THP-1细胞0、 1、 3、 6、 12、 24h,实时荧光定量PCR检测细胞IL-8、 IL-6、 IL-1β、肿瘤坏死因子α(TNF-α)的mRNA水平, ELISA检测细胞培养上清液IL-8蛋白水平,流式细胞术检测THP-1细胞的凋亡, Western blot法检测细胞STAT3、细胞外信号调节激酶(ERK)的蛋白磷酸化水平;采用(0、 1、 5、 10)μmol/L的ERK通路选择性抑制剂U0126预处理THP-1细胞,反转录PCR检测U0126对Stattic诱导THP-1细胞表达IL-8 mRNA水平的影响。结果 (10～20)μmol/LStattic显著上调IL-8在THP-1细胞中的mRNA和蛋白表达,仅(15、 20)μmol/LStattic能诱导THP-1细胞凋亡; Stattic处理THP-1细胞1、 3、 6、 12、 24 h,均显著上调IL-8的mRNA水平,以3 h时最为明显,在6 h以后呈时间依赖性上调IL-8的蛋白水平并诱导THP-1细胞凋亡;Stattic呈浓度和时间依赖性抑制STAT3磷酸化,时间依赖性地诱导ERK磷酸化,在(1、 5、 10、 15、 20)μmol/L时均显著诱导ERK磷酸化。另外, U0126显著抑制Stattic诱导的IL-8 mRNA表达。结论 STAT3抑制剂Stattic通过激活ERK信号通路诱导THP-1细胞凋亡和IL-8产生。     

TRAF6在抗β2GPI/β2GPI复合物诱导THP-1细胞表达组织因子时的活化

目的:探讨肿瘤坏死因子受体相关因子6(TRAF6)在抗β2 GPI/β2 GPI复合物诱导单核细胞株THP-1表达组织因子(TF)中的作用.方法:采用一定剂量抗β2 GPI/β2 GPI复合物刺激THP-1细胞一定时间,收集细胞总RNA及总蛋白,实时定量PCR检测细胞TF mRNA水平,发色底物法检测细胞TF活性;RT-qPCR及Western blot分别检测细胞TRAF6mRNA和蛋白表达情况;进一步采用蛋白酶体抑制剂MG-132,观察是否能够干预抗β2 GPI/β2 GPI复合物对细胞的刺激效应.结果:抗β2 GPI/β2 GPI复合物(100 mg/L)能够刺激THP-1细胞表达TF mRNA及活性,与对照相比差异显著(P<0.05);使细胞TRAF6 mRNA和蛋白表达均增加,并显示时间相关性,分别在刺激15 min和30 min时表达至高峰;MG-132(5μmol/L)明显抑制抗β2 GPI/β2 GPI复合物(100 mg/L)对THP-1细胞TRAF6 mRNA和蛋白的刺激效应及TF的诱导表达.结论:抗β2 GPI/β2 GPI复合物诱导THP-1细胞表达TF过程中,TRAF6被激活并发挥重要作用.     

沙眼衣原体pORF5质粒蛋白激活NALP3炎性复合体诱导THP-细胞产生IL-1β和IL-18

目的:探讨沙眼衣原体(Chlamydia trachomatis,Ct)pORF5质粒蛋白对IL-1β和IL-18等促炎性细胞因子的诱生作用,并初步分析其分子机制。方法:用0、3、6、12、24、36μg/ml不同浓度的pORF5蛋白刺激THP-1细胞,并于0、8、16、24、36 h收集上清及细胞,ELISA检测IL-1β和IL-18的含量;Realtime-PCR检测NALP3炎性复合体mRNA表达水平,Western blot鉴定Caspase-1活化状态;分别用NALP3 siRNA、ASC siRNA转染THP-1细胞24 h或用Caspase-1特异性抑制剂(Z-YVADFMK)预处理THP-1细胞30 min后,再用24μg/ml的pORF5质粒蛋白刺激THP-1细胞24 h,ELISA分析各处理因素对IL-1β和IL-18产生的影响。结果:pORF5质粒蛋白以浓度依赖的方式刺激THP-1细胞产生IL-1β和IL-18。当pORF5质粒蛋白浓度为24μg/ml时,IL-1β和IL-18的表达水平最高,分别为491 pg/ml、186 pg/ml;同时pORF5质粒蛋白以时间依赖的方式刺激THP-1细胞产生IL-1β和IL-18,两者分别在24 h和16 h达到峰值。pORF5质粒蛋白可增强THP-1细胞NALP3、ASC和Caspase-1 mRNA的表达,促进Caspase-1的活化;NALP3-siRNA、ASC-siRNA及Caspase-1抑制剂处理组IL-1β和IL-18的产生水平均显著低于对照组(P0.05)。结论:pORF5质粒蛋白通过激活NALP3炎性复合体诱导THP-1细胞分泌IL-1β和IL-18。     

IL-1通过PKC/MAPK通路上调泡沫细胞ACAT-1的表达及活性

 摘要 目的 研究白细胞介素1(Interleukin 1, IL-1)是否通过蛋白激酶C/丝裂原激活蛋白激酶（PKC/MAPK）信号通路上调泡沫细胞中脂酰CoA胆固醇酯酰转移酶-1（ACAT-1）的表达及活性。方法 复苏并培养人单核细胞株THP-1细胞,与200nM乙酸肉豆蔻佛波酯（PMA）共孵育48h,再与氧化低密度脂蛋白（Ox-LDL）共孵育24h,油红O染色观察细胞质内脂质沉积;检测泡沫细胞、泡沫细胞加IL-1及泡沫细胞加IL-1/IL-1单克隆抗体三组细胞中PKC和MAPK的活性;在三组细胞中分别加入PKC和MAPK抑制剂,分别以Western blot及液相闪烁计数法检测ACAT-1的蛋白表达及酶活性。结果 与PMA共孵育48h后,THP-1细胞逐渐伸出突起,由圆形、悬浮式生长转变为多角形、梭形,呈阿米巴样贴壁生长;经Ox-LDL诱导24h后,油红O染色胞质内可见大量吞噬的脂质小滴。与泡沫细胞组相比,泡沫细胞加IL-1组PKC活性（P<0.05）、MAPK活性（P<0.05）、ACAT-1蛋白表达及活性增加（P<0.05）;PKC抑制剂和MAPK抑制剂能显著抑制IL-1上调ACAT-1表达（P<0.05）及活性（P<0.05）的作用。结论 IL-1上调泡沫细胞ACAT-1表达及活性的作用是通过PKC/MAPK信号通路途径实现的。     

脂多糖对白细胞介素27的调节作用及其与环氧化酶2及前列腺素E2之间的相关性研究

目的 探讨脂多糖(LPS)在THP-1细胞对白细胞介素27(IL-27)的调节作用,阐明IL-27与环氧化酶2(COX-2)及前列腺素E2(PGE2)之间的关系.方法 采用不同浓度的LPS和IL-27刺激THP-1细胞,并在不同时间采用酶联免疫吸附试验(ELISA)检测细胞上清中IL-27和PGE2的含量,同时采用反转录PCR和Western blot检测COX-2的mRNA和蛋白表达的变化.结果 LPS在THP-1细胞能够诱导IL-27的产生,并呈时间和剂量依赖关系;IL-27能够在mRNA和蛋白水平诱导COX-2的表达,同时诱导PGE2的产生,其诱导作用呈时间和剂量依赖效应.结论 LPS能够在细胞水平刺激IL-27的分泌,同时IL-27能够诱导COX-2的表达和PGE2的产生.     

肺炎嗜衣原体Cpn0810重组蛋白诱导THP-1细胞产生促炎因子和凋亡的研究

目的:在E.coliBL21中表达肺炎嗜衣原体Cpn0810,并研究该蛋白能否诱导人单核细胞( THP-1)产生TNF-α和IL-6等促炎因子和细胞凋亡.方法:PCR扩增Cpn0810蛋白编码基因,构建pGEX6p-2/Cpn0810重组质粒,在E.coliBL21中诱导表达,经ToxinEraser纯化柱纯化后,用不同浓度的GST-Cpn0810作用THP-1细胞,ELISA法检测TNF-α和IL-6的水平,Hoechst33258荧光染色、AnnexinV-F1TC-PI染色法检测细胞凋亡情况.结果:构建了重组质粒pGEX6p-2/Cpn0810,并在E.coliBL21菌中高效表达.该蛋白能诱导THP-1细胞以时间、剂量依赖方式表达TNF-α和IL-6;当10mg/L GST-Cpn08 10处理THP-1细胞24h后,形态学上,细胞表现为皱缩、核碎裂、细胞起泡及凋亡小体等凋亡特征.结论:表达并纯化的Cpn0810蛋白能诱导THP-1细胞分泌TNF-α和IL-6等促炎因子和诱导其发生凋亡.     

CPSIT_p7通过激活JNK/ERK信号通路诱导宿主细胞炎症

目的初步探讨鹦鹉热嗜衣原体蛋白CPSIT_p7对宿主细胞炎症反应的调节作用及其分子机制。方法佛波酯(PMA)处理THP-1细胞过夜,诱导其分化为贴壁的巨噬细胞,之后用CPSIT_p7蛋白刺激贴壁细胞,或先用30μmol/L ERK抑制剂PD98059、JNK抑制剂SP600125和p38抑制剂SB202190分别预处理贴壁细胞,再用CPSIT_p7蛋白处理贴壁细胞;Western blot检测ERK、JNK和p38磷酸化水平,ELISA检测各种炎症因子的表达水平。结果 0~10μg/ml CPSIT_p7蛋白刺激PMA诱导的THP-1细胞24 h后,随着CPSIT_p7质量浓度升高,IL-6、IL-1β、IL-8及TNF-α的含量呈剂量依赖性增加;10μg/ml的CPSIT_p7处理细胞0、6、12、24和36 h,在24 h时IL-6、IL-8及IL-1β表达水平达到高峰,而TNF-α在12 h就达到高峰;CPSIT_p7蛋白处理细胞后其ERK和JNK磷酸化水平显著升高,p38磷酸化水平改变不明显;JNK和ERK抑制剂能明显降低CPSIT_p7蛋白诱导的IL-6、IL-1β、IL-8及TNF-α表达。结论 CPSIT_p7通过JNK/MAPKs和ERK/MAPKs信号传导途径诱导THP-1产生IL-1β、IL-6、IL-8及TNF-α炎症因子,与p38/MAPKs信号传导通路无关。     

β2GPI/抗β2GPI抗体复合物激活THP-1细胞内TRIF途径

目的:观察β2GPI/抗β2GPI抗体复合物能否激活单核细胞株THP-1的TRIF途径,以探讨TRIF依赖途径在抗磷脂综合征(APS)发病机制中的作用。方法:采用一定剂量β2GPI/抗β2GPI抗体复合物刺激THP-1细胞一定时间,收集细胞总RNA及总蛋白,荧光定量PCR(RT-PCR)检测细胞TRIF mRNA水平,Western blot检测细胞TRIF蛋白表达情况;进一步观察TLR4途径抑制剂-TAK-242是否干预β2GPI/抗β2GPI抗体复合物对TRIF的诱导表达以及相关细胞因子IL-6、IL-8、TNF-α的表达。结果:β2GPI/抗β2GPI抗体复合物(100 mg/L)能够诱导THP-1细胞表达TRIF(mRNA及蛋白),并显示时间效应,分别于刺激1 h和2 h时TRIF mRNA及蛋白表达至高峰。TAK-242(5μmol/L)能够明显抑制β2GPI/抗β2GPI抗体复合物对THP-1细胞TRIF的诱导表达,同时抑制IL-6、IL-8、TNF-α等炎症因子的表达。结论:TRIF依赖的TLR4途径参与了β2GPI/抗β2GPI抗体复合物对THP-1细胞的激活,提示其在抗磷脂综合征的病理机制中发挥一定作用。     

LDL诱导THP-1细胞炎性因子FOS、TNF-α、IL-1β的顺序表达

目的探讨LDL诱导THP-1细胞内炎性因子FOS、TNF-α、IL-1β表达及3种炎性因子的关系,为早期诊断动脉粥样硬化提供依据。方法采用实时荧光定量PCR检测LDL刺激的THP-1细胞中FOS、TNF-α、IL-1βm RNA的表达,TNF-α抑制剂刺激THP-1细胞中FOS、TNF-α、IL-1βm RNA的表达及TNF-α抑制剂对LDL诱导的THP-1细胞中FOS、TNF-α、IL-1βm RNA表达影响;采用流式细胞仪检测TNF-α抑制剂刺激的THP-1细胞凋亡情况。结果 LDL刺激THP-1细胞FOS m RNA的表达0.5 h达到高峰(P0.05),TNF-αm RNA的表达1 h开始上升并达到最高(P0.05),IL-1βm RNA的表达1 h开始上升(P0.05);TNF-α抑制剂不促进细胞凋亡,100μg/ml时凋亡率最低。TNF-α抑制剂刺激细胞FOS m RNA 2 h表达下降(P0.05),TNF-αm RNA 1 h表达上升(P0.05),2 h表达下降(P0.05),IL-1βm RNA 1 h表达下降(P0.05);LDL诱导细胞1 h后加入TNF-α抑制剂刺激细胞FOS m RNA 1 h表达下降(P0.05),TNF-αm RNA 0.5 h表达下降(P0.05),IL-1βm RNA 0.5 h表达下降(P0.05)。结论 LDL能够促进THP-1细胞内FOS、TNF-α、IL-1β的表达,且它们之间有一定的表达顺序,TNF-α能促进IL-1β的表达。     

The type IVB pili of Salmonella enterica serovar Typhi bind to the cystic fibrosis transmembrane conductance regulator

Salmonella enterica serovar Typhi expresses type IVB pili. We show that the prePilS protein (the soluble precursor form of the structural pilin) interacts with a 15-mer peptide representing the first extracellular domain of the cystic fibrosis transmembrane conductance regulator (CFTR), a recognized human epithelial cell receptor for serovar Typhi (G. B. Pier et al., Nature 393:79-82, 1998). This indicates that after mediating bacterial self-association (C. Morris et al., Infect. Immun. 71:1141-1146, 2003), the pili then act to attach the bacterial clumps to CFTR in the membrane of gut epithelial cells. These sequential type IVB pilus-mediated events cannot be performed by (for example) S. enterica serovar Typhimurium, which may explain why only serovar Typhi causes epidemics of enteric fever in humans.     

Salmonella enterica serovar typhi uses type IVB pili to enter human intestinal epithelial cells

DNA sequencing upstream of the Salmonella enterica serovar Typhi pilV and rci genes previously identified in the ca. 118-kb major pathogenicity island (X.-L. Zhang, C. Morris, and J. Hackett, Gene 202:139-146, 1997) identified a further 10 pil genes apparently forming a pil operon. The product of the pilS gene, prePilS protein (a putative type IVB structural prepilin) was purified, and an anti-prePilS antiserum was raised in mice. Mutants of serovar Typhi either lacking the whole pil operon or with an insertion mutation in the pilS gene were constructed, as was a strain in which the pilN to pilV genes were driven by the tac promoter. The pil(+) strains synthesized type IVB pili, as judged by (i) visualization in the electron microscope of thin pili in culture supernatants of one such strain and (ii) the presence of PilS protein (smaller than the prePilS protein by removal of the leader peptide) on immunoblotting of material pelleted by high-speed centrifugation of either the culture supernatant or sonicates of pil(+) strains. Control pil mutants did not express the PilS protein. A pilS mutant of serovar Typhi entered human intestinal INT407 cells in culture to levels only 5 to 25% of those of the wild-type strain, and serovar Typhi entry was strongly inhibited by soluble prePilS protein (50% inhibition of entry at 1.4 microM prePilS).     

Salmonella enterica serovar Dublin strains which are Vi antigen-positive use type IVB pili for bacterial self-association and human intestinal cell entry

Some strains of Salmonella enterica serovar Dublin are Vi antigen-positive. S. enterica serovar Typhi uses Type IVB pili, encoded adjacent to the viaB locus required for Vi antigen synthesis, to facilitate both eukaryotic cell attachment and bacterial self-association under conditions that favour DNA supercoiling. These pilus-mediated events may be important in typhoid fever pathogenesis. A survey of 17 isolates of S. enterica serovar Dublin showed that all strains which carried the viaB region also carried a serovar Typhi-like Type IVB pil operon, and all serovar Dublin Vi antigen-negative isolates lacked the pil operon. The pil operon was completely sequenced from one of the Vi(+) serovar Dublin strains, and was almost identical (4 nt changes; 3 aa changes, in over 10 kb) to that of serovar Typhi. A pilS mutant of one serovar Dublin strain was constructed, and shown to invade cultured human intestinal INT407 cells to an extent only 20% that of the wild-type parent. Purified prePilS protein inhibited INT407 cell entry by serovar Dublin. The wild-type serovar Dublin strain, but not the pilS mutant, self-associated. The data suggest that the serovar Dublin Type IVB pil operon may increase the human-invasiveness of serovar Dublin, compared to pil-free strains.     

Type IVB pilus operon promoter controlling expression of the severe acute respiratory syndrome-associated coronavirus nucleocapsid gene in Salmonella enterica Serovar Typhi elicits full immune response by intranasal vaccination

Attenuated Salmonella enterica serovar Typhi strains have been considered to be attractive as potential live oral delivery vector vaccines because of their ability to elicit the full array of immune responses in humans. In this study, we constructed an attenuated S. enterica serovar Typhi strain stably expressing conserved nucleocapsid (N) protein of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) by integrating the N gene into the pilV gene, which was under the control of the type IVB pilus operon promoter in S. enterica serovar Typhi. BALB/c mice were immunized with this recombinant strain through different routes: intranasally, orogastrically, intraperitoneally, and intravenously. Results showed that the intranasal route caused the highest production of specific immunoglobulin G (IgG), IgG2a, and secretory IgA, where IgG2a was imprinted as a Th1 cell bias. Moreover, this recombinant live vaccine induced significantly high levels of specific cytotoxic T-lymphocyte activities and increased gamma interferon-producing T cells compared with the parental strain. Our work provides insights into how the type IVB pilus operon promoter controlling SARS-CoV N gene expression in Salmonella might be attractive for a live-vector vaccine against SRAS-CoV infection, for it could induce mucosal, humoral, and cellular immune responses. Our work also indicates that the type IVB pilus operon promoter controlling foreign gene expression in Salmonella can elicit full immune responses by intranasal vaccination.     

Salmonella enterica serovar Paratyphi C carries an inactive shufflon

Salmonella enterica serovar Typhi uses type IVB pili to facilitate bacterial self-association, but only when the PilV proteins (potential minor pilus proteins) are not synthesized. This pilus-mediated event may be important in typhoid fever pathogenesis. We initially show that S. enterica serovar Paratyphi C strains harbor a pil operon very similar to that of serovar Typhi. An important difference, however, is located in the shufflon which concludes the pil operon. In serovar Typhi, the Rci recombinase acts upon two 19-bp inverted repeats to invert the terminal region of the pilV gene, thereby disrupting PilV synthesis and permitting bacterial self-association. In serovar Paratyphi C, however, the shufflon is essentially inactive because each of the Rci 19-bp substrates has acquired a single base pair insertion. A PilV protein is thus synthesized whenever the pil operon is active, and bacterial self-association therefore does not occur in serovar Paratyphi C. The data thus suggest that serovar Typhi bacterial self-association using type IVB pili may be important in the pathogenesis of epidemic enteric fever.     

The shufflon of Salmonella enterica serovar Typhi regulates type IVB pilus-mediated bacterial self-association

Previously, it was shown that type IVB pili encoded by the Salmonella enterica serovar Typhi pil operon are used to facilitate bacterial entry into human intestinal epithelial cells in vitro and that such entry is inhibited by purified prepilin (pre-PilS) protein (X.-L. Zhang, I. S. M. Tsui, C. M. C. Yip, A. W. Y. Fung, D. K.-H. Wong, X. Dai, Y. Yang, J. Hackett, and C. Morris, Infect. Immun. 68:3067-3073, 2000). The pil operon concludes with a simple shufflon, and a recombinase gene product (Rci) inverts DNA in the C-terminal region of the pilV gene to allow synthesis of two distinct PilV proteins, PilV1 and PilV2, which are presumptive minor pilus proteins. We show here that the type IVB pili mediate bacterial self-association, but only when the PilV1 and PilV2 proteins are not expressed. This may be achieved in wild-type serovar Typhi by rapid DNA inversion activity of the shufflon. We show that the inversion activity inhibits the expression of genes inserted between the 19-bp inverted repeats used for Rci-mediated recombination and that the activity of Rci increases when DNA is supercoiled. The data suggest that serovar Typhi self-associates under conditions (such as low oxygen tension in the gut) that favor DNA supercoiling. These results explain (i) the function of the serovar Typhi shufflon and (ii) why there are only two possible shufflon states, in contrast to the many possible states of other shufflon systems. The data further indicate that a very early step in serovar Typhi pathogenesis may be type IVB pilus-mediated self-association of bacteria in the anaerobic human small intestine prior to invasion of the human gut epithelium. The suggested type IVB pilus-dependent step in typhoid fever pathogenesis may partially explain the enhanced invasiveness of serovar Typhi for humans.     

单核细胞—巨噬细胞对伤寒沙门氏菌应答的特性

目的：探讨了人类单核细胞－巨噬细胞对伤寒沙门氏菌应答的特性。方法：采用体外培养的THP－1细胞和PMA诱导分化的THP－1细胞,测定其内在化和杀伤伤寒沙门氏菌的活性,以及以伤寒沙门氏菌诱导的上述两种细胞产生TNF－α和IL－12的情况。结果PMA诱导的THP－1细胞可分化成巨噬细胞;THP－1细胞和PMA诱导分化的THP－1细胞的内在化,杀伤寒沙门氏菌的能力及其产生细胞因子的能力显著不同。结论人类巨噬细胞的可能是机体抗御伤寒沙门氏菌感染的重要细胞。