TRAIL receptor deficiency sensitizes mice to dextran sodium sulphate‐induced colitis and colitis‐associated carcinogenesis

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and its receptor (TRAIL-R) play important roles in immune regulation and cancer cell death. Although TRAIL has been shown to induce chemokine release in various tumour cells, the function of TRAIL-R in the development of colitis and colitis-associated carcinogenesis has not been explored. In this study, we found that TRAIL-R-deficient mice exhibited a higher incidence of colitis and colitis-associated cancer than that of wild-type (WT) mice, and TRAIL-R expression was down-regulated in WT mice that were fed dextran sulphate sodium. Chemokines, including CCL2 and CXCL1, were highly expressed in the serum and inflammatory colon tissues of TRAIL-R^−/− mice compared with WT mice, and TRAIL-R^−/− mice showed a marked infiltration of immune cells during colitis. Hyperactivation of Janus kinase and nuclear factor-κB in colon epithelial cells was also observed, which correlated with the severity of colonic inflammation in TRAIL-R^−/− mice. These data suggest that TRAIL-R plays a protective role in chemical-induced colon injury and negatively regulates mucosal immune responses.     

Expression of tumour necrosis factor-related apoptosis-inducing ligand and caspase-3 in relation to grade of inflammation and stage of fibrosis in chronic hepatitis C

AIM: To assess whether the distribution of the recently described proapoptotic ligand, tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), and the apoptosis effector, caspase-3 alters with the degree of inflammation and fibrosis present in liver biopsy specimens from patients with chronic hepatitis C virus infection. METHODS AND RESULTS: Expression of TRAIL and caspase-3 was assessed immunohistochemically in liver biopsy specimens obtained from 89 adults with chronic hepatitis C. Expression of TRAIL in hepatocytes correlated inversely with stage of fibrosis (P = 0.001), classified according to the Scheuer score; expression of caspase-3 in hepatocytes correlated with grade of inflammation (P = 0.012). Expression of TRAIL in hepatocytes was not correlated with grade of inflammation (P > 0.05); expression of caspase-3 was not correlated with stage of fibrosis (P > 0.05). Maximum expression of proapoptotic TRAIL protein was observed in cases with low grade inflammation (G0) and low stage fibrosis (S1). Maximum expression of caspase-3 in hepatocytes was observed in cases with high grade inflammation (G3-4) and high stage fibrosis (S3), but not with liver cirrhosis (S4). CONCLUSIONS: There is a significant decrease in TRAIL expression with increasing grade of inflammation, whereas caspase-3 expression is significantly increased with advanced fibrosis, short of cirrhosis.     

TRAIL对多种肿瘤细胞的杀伤作用

目的： 研究肿瘤坏死因子相关凋亡诱导配体（TRAIL）作用下多种肿瘤细胞的生长抑制效应及凋亡诱导情况。方法： 利用大肠杆菌基因工程菌表达非融合rhsTRAIL，进行目的蛋白的分离纯化，得到rhsTRAIL样品，纯度为97%。通过倒置显微镜下观察、MTT法、流式细胞仪法检测其对细胞的生长抑制和诱导凋亡情况。结果： 一定浓度的TRAIL 可有效抑制LS174-T细胞、MCF-7细胞、GLC细胞、7402细胞、Jurkut T细胞生长，其生长抑制率具剂量依赖性，且各细胞对TRAIL敏感性不同，其中Jurkat T细胞最为敏感。用2 mg/L TRAIL作用Jurkat T细胞0-72 h，6 h后细胞即发生明显凋亡，其细胞凋亡率具时间依赖性。结论： 所制备的TRAIL可抑制多种肿瘤细胞生长，并诱导Jurkat T细胞凋亡。     

重组人可溶性TRAIL分子诱导白血病细胞株凋亡的研究

比较重组人可溶性TRAIL(rhsTRAIL)诱导Jurkat细胞株、K562细胞株以及HL-60细胞株凋亡之间的差异,探讨这些差异与细胞表面TRAIL受体(DR4、DR5、DcR1和DcR2)表达量的关系。不同浓度的rhsTRAIL分别处理Jurkat细胞、K562细胞和HL-60细胞12 h、24 h和48 h后,用流式细胞仪检测经碘化丙啶(PI)染色后的细胞凋亡情况;用RT-PCR方法检测细胞表面受体DR4、DR5、DcR1、DcR2的表达。培养12 h、24 h、48 h后,不同浓度rhsTRAIL诱导Jurkat细胞株的凋亡率均明显高于对照组,且具有剂量依赖性和时间依赖性;但K562细胞株和HL-60细胞株未见明显的凋亡发生。RT-PCR结果显示,培养12 h、24 h、48 h后,Jurkat细胞株表面DR4的表达随时间的延长和rhsTRAIL浓度的升高而升高,而DR5、DcR1和DcR2的表达未检出;K562和HL-60细胞株表面DR4的表达没有明显变化,而且DR5、DcR1和DcR2的表达也未检出。rhsTRAIL诱导Jurkat细胞株的凋亡具有剂量依赖性和时间依赖性,且与其细胞表面DR4的表达呈正相关;在一定的浓度条件下,rhsTRAIL未能诱导K 562和HL-60细胞株发生明显凋亡,且其细胞表面DR4的表达也未见明显变化。这些结果提示,应用TRAIL治疗不同种类白血病时,应注意它的使用剂量和适应范围。     

慢性乙肝患者外周血单个核细胞TRAIL受体表达及其临床意义

目的探索慢性乙肝患者外周血单个核细胞(PBMC)肿瘤细胞坏死因子相关的凋亡诱导配体(TRAIL)受体在PBMC凋亡中的作用,及其与机体肝脏损伤的相关性。方法用RT-PCR和流式细胞术检测55例慢性乙肝患者(包括轻度、中度、重度)外周血单个核细胞TRAIL各受体(DR4、DR5、DcR1和DcR2)表达水平,同时检测肝功能相关指标,并进行相关性分析。以30例正常人作为对照。结果诱骗受体DcR1在慢性乙肝患者中的表达显著低于对照组(P<0.05)。DcR1的表达随慢性乙肝病情的加重而逐渐降低。慢性乙肝患者的DcR1表达与转氨酶(ALT)呈显著负相关,与血清白蛋白成显著正相关。结论慢性乙肝患者外周血单个核细胞DcR1表达下调可能是其细胞凋亡增加的机制之一,且DcR1表达情况可从一定程度上反映肝脏的损伤程度。     

Interleukin‐15‐activated natural killer cells kill autologous osteoclasts via LFA‐1, DNAM‐1 and TRAIL,and inhibit osteoclast‐mediated bone erosion in vitro

Osteoclasts reside on bone and are the main bone resorbing cells playing an important role in bone homeostasis, while natural killer (NK) cells are bone‐marrow‐derived cells known to play a crucial role in immune defence against viral infections. Although mature NK cells traffic through bone marrow as well as to inflammatory sites associated with enhanced bone erosion, including the joints of patients with rheumatoid arthritis, little is known about the impact NK cells may have on mature osteoclasts and bone erosion. We studied the interaction between human NK cells and autologous monocyte‐derived osteoclasts from healthy donors in vitro. We show that osteoclasts express numerous ligands for receptors present on activated NK cells. Co‐culture experiments revealed that interleukin‐15‐activated, but not resting, NK cells trigger osteoclast apoptosis in a dose‐dependent manner, resulting in drastically decreased bone erosion. Suppression of bone erosion requires contact between NK cells and osteoclasts, but soluble factors also play a minor role. Antibodies masking leucocyte function‐associated antigen‐1, DNAX accessory molecule‐1 or tumour necrosis factor‐related apoptosis‐inducing ligand enhance osteoclast survival when co‐cultured with activated NK cells and restore the capacity of osteoclasts to erode bone. These results suggest that interleukin‐15‐activated NK cells may directly affect bone erosion under physiological and pathological conditions.     

TRAIL及其受体DR5与动脉粥样硬化关系的初步研究

目的探讨肿瘤坏死因子(INF)相关的凋亡诱导配体(TRAIL)及其受体DR5与动脉粥样硬化(AS)之间的关系。方法冠心病(CAD)组61例,正常对照组22例。应用酶联免疫吸附法测定血浆可溶性TRAIL(sTRAIL)和可溶性DR5(sDR5)水平。免疫组织化学测定冠状动脉TRAIL和DR5蛋白表达情况。结果CAD组血浆sTRAIL和sDR5水平均显著性升高(P<0.001,P<0.05)。3支血管病变组和双支血管病变组血浆sTRAIL和sDR5水平均分别显著高于单支血管病变组和正常对照组(P<0.01,P<0.01,P<0.01,P<0.05)。TRAIL和DR5主要表达于平滑肌细胞的胞质,TRAIL还可表达于AS中的巨噬细胞。AS组冠状动脉的TRAIL和DR5表达明显高于非AS组(P<0.01,P<0.05)。结论TRAIL及其受体DR5可能参与了AS的进展,其浓度越高,冠状动脉病变越重。     

Role of natural interferon-producing cells and T lymphocytes in porcine monocyte-derived dendritic cell maturation

Maturation of dendritic cells (DC) is a key immunological process regulating immune responses to pathogens and vaccines, as well as tolerance and autoimmune processes. Consequently, the regulation of DC maturation should reflect these multifaceted immunological processes. In the present study, we have defined the role of particular cytokines, Toll-like receptor (TLR) ligands and T lymphocytes in the porcine monocyte-derived DC (MoDC). Interferon-alpha (IFN-alpha) alone was a poor inducer of MoDC maturation, but in association with tumour necrosis factor-alpha (TNF-alpha), or TLR ligands such as lipopolysaccharide and polyinosinic-polycytidylic acid I:C, an up-regulation of major histocompatibility complex II and CD80/86 expression was noted, along with reduced endocytic activity. In contrast, TNF-alpha alone or in combination with the TLR ligands was a poor inducer of DC maturation, but co-operated with T-lymphocytes in the presence of antigen to induce DC maturation. Natural interferon producing cells (NIPC, or plasmacytoid DCs) represent a danger-recognition system of the immune defences, and can respond to viruses not otherwise recognized as posing a danger. Indeed, MoDC did not respond to transmissible gastroenteritis virus (TGEV), whereas NIPC produced high levels of IFN-alpha and TNF-alpha after TGEV stimulation. Moreover, supernatants from the stimulated NIPC induced maturation in MoDCs. These matured MoDCs displayed an enhanced ability to present antigen to and thus stimulate T cells. Taken together, the present work demonstrates that maturation of MoDC not only results from TLR signalling, but can require co-operation with various cell types--principally NIPC and activated T cells--which would reflect the particular immunological situation.     

TRAIL基因与鸡贫血病毒vp3基因体外协同效应的研究

目的研究TRAIL基因与鸡贫血病毒vp3基因在体外协同诱导肝癌细胞系HepG2凋亡的作用。方法从人外周血淋巴细胞总RNA中扩增出TRAIL基因的cDNA序列,构建含TRAIL基因的真核表达重组体,与鸡贫血病毒vp3基因在体外共转染HepG2细胞,研究其协同诱导HepG2细胞凋亡作用。结果 单独转染TRAIL基因与vp3基因均可诱导HepG2细胞凋亡;将两种基因共转染HepG2细胞,发现其凋亡率明显增加。结论TRAIL基因与vp3基因在诱导HepG2细胞凋亡中存在正协同效应。     

TRAIL诱导HBV转染肝癌细胞BEL-7402凋亡的作用及机制研究

目的　研究肝癌细胞BEL- 74 0 2感染HBV前后,TRAIL诱导其凋亡的敏感度变化及作用机制。方法　构建含1.1倍HBV全基因组的真核表达载体pcDNA3 1.1HBV ,转染人肝癌细胞BEL -74 0 2 ,G4 18稳定筛选,建立HBVadr亚型体外转染的细胞模型。原位末端标记(TUNEL)检测TRAIL诱导的凋亡反应,并通过设立TRAIL联合其可溶性受体sDR5 (sDR5与TRAIL结合后,可特异性阻断TRAIL诱导凋亡) ,以证实该凋亡是由TRAIL特异性诱导的。琼脂糖凝胶电泳(DNAladder)检测染色体DNA的断裂情况。流式细胞术、半定量逆转录聚合酶链反应检测HBV感染前后细胞表面TRAIL各受体的表达。双荧光素酶报告基因系统检测抑制凋亡的核转录因子NF κB的活性。结果　成功构建了包含HBV全基因组的真核表达载体pcDNA3 1.1HBV ,转染BEL 74 0 2、经G4 18稳定筛选后得到HBVadr亚型转染的细胞模型BEL 74 0 2 1.1HBV。TRAIL诱导BEL 74 0 2、BEL 74 0 2 pcDNA3及BEL 74 0 2 1.1HBV的凋亡率分别为30 .5 %、2 9.8%和76 % (P <0 .0 1) ;经sDR5特异性阻断后,凋亡率分别为0 .9%、0 .8%和0 .9% ,证明凋亡是由TRAIL特异性诱导的。TRAIL作用2 4h后,琼脂糖凝胶电泳可见BEL- 74 0 2 1.1H-BV较BEL- 74 0 2、BEL 74 0 2 pcDNA3染色体DNA断裂的现象更为明显。无论RNA水平还     

sDR5封闭TRAIL减少内毒素引起小鼠肝细胞凋亡

目的 探讨肿瘤坏死因子相关凋亡诱导配体(TRAIL)在内毒素诱导小鼠肝细胞凋亡中的作用.方法 内毒素作用于可溶性死亡受体-5(sDR5)封闭TRAIL的小鼠,不同时间检测小鼠血清中的谷丙转氨酶(ALT)、谷草转氨酶(AST)和乳酸脱氧酶(LDH)的含量;HE染色及Annexin V、PI双染法流式细胞术检测小鼠肝细胞凋亡;免疫组织化学法及流式细胞术检测小鼠肝细胞和肝细胞膜表面DR5的表达.结果 内毒素可以上调肝细胞DR5的表达.DR5封闭TRAIL可显著抑制内毒素引起的小鼠肝细胞凋亡和改善肝细胞损伤.结论 内毒素引起疾病过程中TRAIL起重要作用.     

Levels of CD40 expression on dendritic cells dictate tumour growth or regression

Tumour regression requires activation of T cells. It has been shown that the interaction between T cell-expressed CD40-ligand (CD40-L) and antigen-presenting cell-expressed CD40 plays a crucial role in T cell activation. CD40-L- or CD40-deficient mice are susceptible to tumour growth. CD40-based therapies are also shown to control tumour growth significantly, suggesting that CD40-CD40-L interaction induces anti-tumour T cell responses and tumour regression. We demonstrate that the anti-tumour T cell response can be modulated reciprocally as a function of the levels of CD40 expression. At low expression levels, CD40 promotes tumour growth; at higher expression levels, CD40 induces tumour-regressing T cell response. Dendritic cells (DC) sorted onto major histocompatibility complex (MHC)-II expression are found to be similar in CD40 and CD80 expression. The MHC-II(hi)/CD40(hi) DC induce interleukin (IL)-12-dominated and T helper 1 (Th1)-type response, whereas MHC-II(lo)/CD40(lo) DC promote high IL-10 and Th2-type T cells. The T cells induced by these DC also differ in terms of regulatory T cell markers, lymphocyte activation gene-3 (LAG-3) and glucocorticoid-induced tumour necrosis factor (TNF) receptor family-related gene (GITR). Thus, we report for the first time that CD40-induced effector T cell response depends on CD40 expression levels in vivo.     

Origin and differentiation of dendritic cells

Despite extensive, recent research on the development of dendritic cells (DCs), their origin is a controversial issue in immunology, with important implications regarding their use in cancer immunotherapy. Although, under defined experimental conditions, DCs can be generated from myeloid or lymphoid precursors, the differentiation pathways that generate DCs in vivo remain unknown largely. Indeed, experimental results suggest that the in vivo differentiation of a particular DC subpopulation could be unrelated to its possible experimental generation. Nevertheless, the analysis of DC differentiation by in vivo and in vitro experimental systems could provide important insights into the control of the physiological development of DCs and constitutes the basis of a model of common DC differentiation that we propose.     

The presence of interleukin-27 during monocyte-derived dendritic cell differentiation promotes improved antigen processing and stimulation of T cells

Dendritic cells (DCs) are potent antigen-presenting cells necessary to establish effective adaptive immune responses. The cytokine environment that exists at the time of DC differentiation may be an important but often ignored determinant in the phenotypic and functional properties of DCs. Interleukin-27 (IL-27) is a unique cytokine that has both inflammatory and immune suppressive activities. Although it can both promote and oppose activity of different T-cell subsets, mostly anti-inflammatory activity has been described toward macrophages and DCs. However, the specific effect of IL-27 during DC differentiation and how that may change the nature of the antigen-presenting cell has not been investigated. In this report, we show that IL-27 treatment during monocyte-derived DC differentiation enhanced the ability to process antigens and stimulate T-cell activity. DCs differentiated in the presence of IL-27 showed enhanced acidification of latex bead-containing phagosomes that was consistent with elevated expression of vacuolar-ATPases. This resulted in inhibition of intracellular growth of Staphylococcus aureus. In addition, the levels of MHC class II surface expression were higher in DCs differentiated in the presence of IL-27. Production of IL-12 was also significantly increased during S. aureus infection of IL-27-differentiated DCs. The net effect of these activities was enhanced CD4⁺ T-cell proliferation and T helper type 1 cytokine production. These findings are important to a wide number of immunological contexts and should be considered in the development of future vaccines.     

Apoptotic cells induce dendritic cell-mediated suppression via interferon-gamma-induced IDO

Dendritic cells (DC) are sensitive to their local environment and are affected by proximal cell death. This study investigated the modulatory effect of cell death on DC function. Monocyte-derived DC exposed to apoptotic Jurkat or primary T cells failed to induce phenotypic maturation of the DC and were unable to support CD4+ allogeneic T-cell proliferation compared with DC exposed to lipopolysaccharide (LPS) or necrotic cells. Apoptotic cells coincubated with LPS- or necrotic cell-induced mature DC significantly suppressed CD80, CD86 and CD83 and attenuated LPS-induced CD4+ T-cell proliferation. Reduced levels of interleukin-12 (IL-12), IL-10, IL-6, tumour necrosis factor-alpha and interferon-gamma (IFN-gamma) were found to be concomitant with the suppressive activity of apoptotic cells upon DC. Furthermore, intracellular staining confirmed IFN-gamma expression by DC in association with apoptotic environments. The specific generation of IFN-gamma by DC within apoptotic environments is suggestive of an anti-inflammatory role by the induction of indoleamine 2,3-dioxygenase (IDO). Both neutralization of IFN-gamma and IDO blockade demonstrated a role for IFN-gamma and IDO in the suppression of CD4+ T cells. Moreover, we demonstrate that IDO expression within the DC was found to be IFN-gamma-dependent. Blocking transforming growth factor-beta (TGF-beta) also produced a partial release in T-cell proliferation. Our study strongly suggests that apoptosis-induced DC suppression is not an immunological null event and two prime mediators underpinning these functional effects are IFN-gamma-induced IDO and TGF-beta.     

肿瘤坏死因子相关凋亡诱导配体在外周血单个核细胞中的表达

目的 :研究肿瘤坏死因子相关凋亡诱导配体 (TRAIL)在外周血单个核细胞 (PBMC)中的表达及其意义。方法 :用免疫组织化学的方法检测PBMC中TRAIL的表达情况。结果 :淋巴细胞分离液得到的PBMC中 ,淋巴细胞占 (97.4 8± 3.4 3) % ,单核细胞占 (3.15± 0 .83) % ,TRAIL免疫反应阳性的淋巴细胞占总数的 (2 6 .31± 3.18) % ,呈TRAIL免疫反应阳性的单核细胞占总数的(1.0 4± 0 .13) % ,TRAIL免疫反应阳性物质分布于胞质内 ,核呈阴性反应。结论 :正常人外周血分离的淋巴细胞及单核细胞有TRAIL表达。     

The influence of infectious factors on dendritic cell apoptosis

Pathogens can have a negative influence on dendritic cells (DCs), causing their apoptosis, which prevents active presentation of foreign antigens. It results in a state of immunosuppression which makes the body susceptible to secondary infections. Infected immature DCs have lower expression of co-stimulatory and adhesion molecules, reduced ability to secrete cytokines and an inhibited maturation process and are incapable of effective antigen presentation and activation of T-lymphocytes. In some cases, the ability of DCs to undergo rapid apoptosis is important for the body defense, which is probably because of DCs’ ability to cross-present and cooperate with other cells. Apoptotic bodies released from the infected DCs are phagocytosed by other DCs, which then stimulate the effector cells and present antigens more efficiently than infected cells. The aim of this article is to review how the DCs respond to viral and bacterial factors and which biochemical mechanisms are responsible for their apoptosis.     

Autologous apoptotic T cells interact with dendritic cells,but do not affect their surface phenotype or their ability to induce recall immune responses

Dendritic cells (DCs) play an important role in determining immunogenicity and the subsequent immune response. They may also have a role in maintaining peripheral tolerance to self-antigens by initiating an immune response only in the context of danger signals released from cells during stress, damage or death. These signals may originate from surrounding T cells as well as from other cells. Therefore, in this study the effect of autologous T cell injury on DC morphology and function has been investigated. Co-incubation of apoptotic or necrotic T cells with immature DCs altered their morphology towards a more mature appearance, with more cells showing activation as judged by spreading and formation of arborizing long processes. The apoptotic autologous T cells were rarely phagocytosed by immature DCs, compared to macrophages. The DC surface phenotype was not affected by the co-incubation with autologous injured T cells. The ability of DCs to elicit a secondary immune response was not altered by exposure to autologous injured T cells. These findings suggest that DC can continue to function in T cell activation, rather than in tolerogenic mode, even in the presence of large numbers of dying autologous T cells, such as may be present in the aftermath of an acute antiviral response.