肿瘤坏死因子α及其基因多态性在慢性阻塞性肺疾病的作用研究进展

肿瘤坏死因子α（TNF-α）是一种重要的细胞因子,它参与了慢性阻塞性肺疾病（COPD）炎症反应。TNF-α基因多态性被认为是COPD的易感因素之一,但相关报道不尽一致。本文就TNF-α基因多态性在COPD中的作用及其研究进展作一综述。     

黑龙江地区慢性阻塞性肺疾病与肿瘤坏死因子基因多态性的相关性研究

肿瘤坏死因子（TNF）在慢性阻塞性肺疾病（COPD）的气道炎症和肺功能损害中起重要作用。已知肿瘤坏死因子α（TNF-α）和TNF-β存在单核苷酸多态性（SNP）TNF-α-308G/A和TNF-β＋252G/A，影响TNF在气道内的表达，因而可能是COPD发病的分子机制之一。我们的研究采用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）和等位基因特异性聚合酶链反应（AS-PCR）方法，分析黑龙江地区汉族COPD患者及健康人群的TNF基因多态性分布情况，探讨其多态性在COPD发病中的作用。     

肿瘤坏死因子-α在OSAHS-COPD重叠综合症及OSAHS中的血清水平研究

目的 探讨OSAHS及OSAHS—COPD重叠综合症患者肿瘤坏死因子-α的血清水平和经过经鼻持续气道正压通气治疗的影响。方法 采用双抗体夹心酶联免疫吸附法（EUSA）测定阻塞性睡眠呼吸暂停-低通气综合症组20例、重叠综合症组20例和健康对照组20例的血清肿瘤坏死因子-α水平。OSAHS组及OSAHS—COPD重叠综合症均经1个月持续气道正压通气（nCPAP）治疗一个月,然后复查血清肿瘤坏死因子-α。结果：OSAHS组及OSAHS—COPD重叠综合症组患者血清肿瘤坏死因子-α水平较健康对照组明显升高（P〈0．001）。经鼻持续气道正压通气（nCPAP）显著地降低了OSAHS组及OSAHS—COPD重叠综合症组血清肿瘤坏死因子-α水平。但OSAHS组及OSAHS—COPD重叠综合症组血清肿瘤坏死因子-α水平相比较无论治疗前后均无明显统计学差异。结论 血清肿瘤坏死因子-α水平在OSAHS组及OSAHS—COPD重叠综合症组患者中明显升高,经过经鼻气道正压通气治疗后下降。OSAHS组及OSAHS—COPD重叠综合症组无论治疗前、后比较均无明显统计学差异。     

基因多态性和COPD易感性研究进展

现代医学表明许多疾病的发病和基因有关,COPD也不例外;COPD感性和基因的关系研究在国外已有几十年,然而大量的研究多集中在α_1-AT方面,近几年来有关微粒体环氧化物水解酶基因、谷胱甘肽S转移酶基因、维生素D结合蛋白基因、肿瘤坏死因子基因和微卫星DNA与COPD易感性关系的研究十分活跃,现就这方面的进展综述如下。     

035 基因多态性和COPD易感性研究进展

现代医学表明许多疾病的发病和基因有关,COPD也不例外;COPD易感性和基因的关系研究在国外已有几十年,然而大量的研究多集中在α1-AT方面,近几年来有关微粒体环氧化物水解酶基因、谷胱甘肽S转移酶基因、维生素D结合蛋白基因、肿瘤坏死因子基因和微卫星DNA与COPD易感性关系的研究十分活跃,现就这方面的进展综述如下.     

基因多态性和COPD易感性研究进展

现代医学表明许多疾病的发病和基因有关,COPD也不例外,COPD易感性和基因的关系研究在国外已有几十年,然而大量的研究多集中在α1-AT方面,近几年来有关微粒体环氧化物水解酶基因,谷胱甘肽S转移酶基因,维生素D结合蛋白基因,肿瘤坏死因子基因和微卫生DNA与COPD易感性关系的研究十分活跃,现就这方面的进展综述如下。     

肿瘤坏死因子α对人脐静脉内皮细胞纤溶酶原激活物抑制剂1表达及转录调控的影响

探讨肿瘤坏死因子α对人脐静脉内皮细胞纤溶酶原激活物抑制剂1活性和mRNA表达的影响，以及纤溶酶原激活物抑制剂1基因5’上游序列的调控元件在该基因转录调控中的作用。体外培养人脐静脉内皮细胞，加入不同浓度肿瘤坏死因子α作用不同时间。采用发色底物法测定纤溶酶原激活物抑制剂1活性。Northern印迹分析法测定纤溶酶原激活物抑制剂1 mRNA水平。基因重组技术构建四个含人纤溶酶原激活物抑制剂1基因不同长度5’上游序列的荧光素酶报告基因质粒，瞬时转染进入内皮细胞，并测定荧光素酶的表达情况。运用聚合酶链反应和序列分析法对构建质粒上的三个AP-元件分别进行定点突变。结果发现，不同浓度肿瘤坏死因子α作用人脐静脉内皮细胞后，纤溶酶原激活物抑制剂1活性和mRNA表达量均明显增高；当转染质粒含有纤溶酶原激活物抑制剂1基因上游序列-1509/ 90和-823／ 90时，肿瘤坏死因子α使转染细胞的荧光素酶表达量比对照组明显增高；当转染质粒含有-553／ 90和-47， 90时，肿瘤坏死因子α的诱导作用不明显。在纤溶酶原激活物抑制剂15’上游序列的三个AP-1元件突变后，肿瘤坏死因子α的诱导作用明显降低。结果提示，肿瘤坏死因子α增强血管内皮细胞纤溶酶原激活物抑制剂1活性与mRNA表达；纤溶酶原激活物抑制剂1活性提高与其mRNA表达增加呈正相关；纤溶酶原激活物抑制剂15’上游序列中三个AP-1元件在肿瘤坏死因子α对纤溶酶原激活物抑制剂1诱导中具有重要调控作用。     

易感基因多态性与慢性阻塞性肺疾病遗传易感性的研究

目的 探讨中国北方汉族人群吸烟、血红素加氧酶-1(HO-1)、肿瘤坏死因子-α(TNF-α)、人类β防御素-1(hBD-1)基因多态性与慢性阻塞性肺疾病(COPD)之间的关系.方法 采用病例对照研究和聚合酶链反应-限制性片段长度多态性等技术,检测COPD患者HO-1、TNF-α、hBD-1基因型频率分布结果 COPD组和健康对照组HO-1 L型等位基因频率为23.44%和10.71%,两者差异有统计学意义(P＜0.05);TNF-α突变型基因频率在两组中的频率分别为18.24%和7.53%,两组比较差异有统计学意义(P＜0.05);hBD-1突变型基因频率在两组中的频率分别为14.28%和5.00%,两者差异有统计学意义(P＜0.01).结论 HO-1、TNF-α、hBD-1基因多态性与COPD发生相关.     

低氧诱导因子1α进大鼠肺泡巨噬细胞肿瘤坏死因子α的产生

低氧诱导因子1α(hypoxia inducible factor-1α，HIF-1α)是介导细胞缺氧反应的关键核转录因子，在巨噬细胞等髓系细胞介导的炎症反应中发挥着重要的作用。肺部和气道的慢性非特异性炎症是慢性阻塞性肺疾病(COPD)的重要特征，活化的巨噬细胞及其释放的炎症介质如肿瘤坏死因子α(TNF-α)等与这一慢性炎症过程密切相关。     

肿瘤坏死因子α+489G/A基因多态性与慢性阻塞性肺疾病的相关性研究

目的 探讨肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)+489基因多态性与慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)易感性的关系.方法 用聚合酶链反应-限制性片段长度多态性技术对55例COPD患者、47例对照组(性别、年龄和吸烟史配对)和55名健康查体组的TNF-α+489G/A基因多态性进行检测,并对其易感性进行分析.结果 COPD组、对照组及健康查体组携带GA/AA基因型的发生率分别为23.6%、14.3%和9.1%,3组间差异无统计学意义(P＞0.05).当COPD组与健康查体组比较,携带等位基因A的人群更易发生COPD(P＜0.05).COPD组携带GA/AA基因型患者肺源性心脏病的发病率明显高于携带GG基因型的患者(P＜0.05).结论 在TNF-α+489位点上携带等位基因A的人群可能是发生COPD的一个高危因素,且预后不佳.     

Tumor necrosis factor-alpha induces a kappa B sequence-specific DNA-binding protein in human hepatoblastoma HepG2 cells

Tumor necrosis factor-alpha is an inducer of acute-phase protein synthesis in liver cells. The mechanism by which tumor necrosis factor-alpha alters gene expression in these cells is largely unknown. In this study, we demonstrate that tumor necrosis factor-alpha stimulates human immunodeficiency virus-1 long terminal repeat-promoted gene expression in the human hepatoblastoma HepG2 cell line and increased binding of trans-activating factors to kappa B (kappa B) DNA sequences. In contrast to lymphocytic cells where the nuclear factors recognizing the kappa B sequences are activated by both tumor necrosis factor-alpha and phorbol-12-myristate-13-acetate through a posttranslational mechanism, in HepG2 cells phorbol-12-myristate-13-acetate does not activate these factor(s), and de novo protein synthesis seems to be required in HepG2 cells for gene activation by tumor necrosis factor-alpha.     

Tumor necrosis factor-alpha gene -308G>A polymorphism is associated with ST-elevation myocardial infarction and with high plasma levels of biochemical ischemia markers

OBJECTIVES: As is well known, acute myocardial infarction presents two electrocardiogram (EKG) patterns, ST-elevation (STEMI) and no ST-elevation (NSTEMI), characterized by different coronary artery thrombotic occlusion. Growing evidence shows that inflammation plays a central role in the pathogenesis of acute myocardial infarction. Among the factors that promote inflammation and arterial thrombosis, one of the most important is the proinflammatory cytokine tumor necrosis factor-alpha. The expression of this cytokine is modulated by a polymorphism located at nucleotide -308 of tumor necrosis factor-alpha promoter gene. The objective of our study is to verify whether tumor necrosis factor-alpha -308 polymorphism is associated with risk of acute myocardial infarction (STEMI and NSTEMI) or with biochemical myocardial ischemia markers, such as troponin I, creatine kinase-MB, lactate dehydrogenase and myoglobin. METHODS: We analyzed tumor necrosis factor-alpha -308 polymorphism in a total of 603 study participants: 293 elderly patients affected by acute myocardial infarction (STEMI and NSTEMI) and 310 healthy controls. RESULTS: We found that individuals carrying the tumor necrosis factor-alpha -308 AG+AA genotypes are significantly more represented among acute myocardial infarction patients affected by STEMI than among NSTEMI patients (OR = 1.86, 95% CI 1.08-3.21, p = 0.027) and healthy controls (OR = 1.64, 95% CI 1.03-2.64, p = 0.046). Furthermore, the patients carrying tumor necrosis factor-alpha -308 AG+AA genotypes displayed significant increased levels of biochemical myocardial ischemia markers. CONCLUSIONS: Our study shows a significant association between the tumor necrosis factor-alpha -308 polymorphism and the occurrence of STEMI, and suggests that the tumor necrosis factor-alpha -308 polymorphism could play a role in the pathogenesis of cardiac ischemic damage, AA+AG genotype carrier individuals being likely to be affected by more severe ischemic damage than the rest of the population.     

Myocardial tumor necrosis factor-alpha expression in a sudden death due to dilated cardiomyopathy with endomyoelastofibrosis

During the clinical course of dilated cardiomyopathy, arrhythmias, thromboembolism and sudden death are common and may occur at any stage. In patients with dilated cardiomyopathy, elevated plasma levels of tumor necrosis factor-alpha are associated with poor prognosis. In animal experiments and clinical trials, myocardial tumor necrosis factor-alpha expression correlates with increased mortality rates. A case of sudden death of a previously asymptomatic young man, having a definitive autoptic diagnosis of dilated cardiomyopathy with endomyoelastofibrosis, is presented. We investigated the cardiac morphology and the expression of tumor necrosis factor-alpha in cardiac tissue specimens to elucidate the role of tumor necrosis factor-alpha expression in this fatal case. Our results demonstrate a strong positive myocytes reaction for tumor necrosis factor-alpha in the heart specimens. The pathogenesis of the fatal event is discussed with particular reference to the histological findings and myocytes expression of tumor necrosis factor-alpha.     

Ethnic differences in polymorphisms of tumor necrosis factor-alpha, interleukin-10, and transforming growth factor-beta1 genes in patients with chronic hepatitis C virus infection

Ethnic differences in the outcome of hepatitis C have been described. Our aim was to investigate ethnic differences in the distribution of genotypes associated with polymorphisms of the tumor necrosis factor-alpha promoter, interleukin-10 promoter, and transforming growth factor-beta1 leader sequence in patients with hepatitis C. Genomic DNA was obtained from 71 Egyptians and 67 Caucasians (hepatitis C and control patients). Amplification of appropriate gene segments was followed by direct sequencing. Infrequently occurring polymorphisms were identified at positions -244 and -77 of the tumor necrosis factor-alpha promoter and at positions -851 and -657 of the interleukin-10 promoter. The G/A genotype associated with tumor necrosis factor-alpha promoter positions -376 and -244 was more frequent in Egyptians (P =0.001 and P =0.004, respectively). The -244 G/A genotype occurred only in healthy Egyptians (P =0.024). Thus, ethnic differences in the distribution of genotypes of the tumor necrosis factor-alpha promoter exist, which may have clinical implications on the outcome of hepatitis C.     

Increased tumor necrosis factor-alpha receptor number in chronic hepatitis B virus infection.

Production of the antiviral cytokine, tumor necrosis factor-alpha is increased in chronic hepatitis B virus infection, and clinical studies of tumor necrosis factor-alpha have indicated a proviral effect at higher doses. To determine whether this might be related to abnormal cell surface tumor necrosis factor-alpha receptor expression, binding characteristics of cell surface tumor necrosis factor-alpha receptor on peripheral blood mononuclear cells in chronic hepatitis B virus carriers were studied using radioiodinated recombinant tumor necrosis factor-alpha. The specific binding curves generated were analyzed according to the method of Scatchard to determine cell surface receptor numbers and dissociation constants. A single class of cell surface tumor necrosis factor-alpha receptor was demonstrated on peripheral blood mononuclear cells and mononuclear subsets. The median number (range) of cell surface tumor necrosis factor-alpha receptors on peripheral blood mononuclear cells from controls (n = 11), chronic hepatitis B virus patients seropositive for hepatitis B virus DNA (n = 8) and seronegative for hepatitis B virus DNA (n = 8) were 2,329 (range = 1,538 to 3,133), 3,375 (range = 2,300 to 6,718) (p less than 0.01) and 3,113 (range = 2,229 to 5,246) (p less than 0.05) sites/cell, respectively. They all had similar dissociation constants of 8.4 x 10(-10) mol/L (range = 4.1 to 16.9), respectively. Further dissection of the peripheral blood mononuclear cells showed that this increase in cell surface receptor number was confined to the monocyte fraction (p less than 0.01). Plasma tumor necrosis factor-alpha levels in five patients with increased monocyte cell surface tumor necrosis factor-alpha receptor numbers were also elevated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Involvement of tumor necrosis factor-alpha in the pathogenesis of activated macrophage-mediated hepatitis in mice

The possible involvement of tumor necrosis factor-alpha in the pathogenesis of an experimentally induced hepatitis was investigated. Balb/c mice were primed with Propionibacterium acnes to induce the infiltration of mononuclear cells into the liver. Immunohistochemical study showed that most of the accumulated mononuclear cells at 7 days were Mac-2 positive, suggesting that they were activated macrophages. An injection of lipopolysaccharide resulted in massive hepatic necrosis and high mortality in the mice within 24 hours. Plasma tumor necrosis factor-alpha activity initially rose sharply and then declined over 3 hours. The increase in plasma aminotransferase activity correlated well with the elevation of plasma tumor necrosis factor-alpha activity. Pretreatment with dexamethasone or 16,16-dimethyl-prostaglandin E2 attenuated not only the elevation of plasma tumor necrosis factor-alpha activity but also the increase in plasma aminotransferase activity and improved the survival rate. Passive immunization against tumor necrosis factor-alpha showed protective effects. These findings suggest that tumor necrosis factor-alpha released from activated macrophages may play a crucial role in the pathogenesis of this murine hepatitis.     

In vitro effects of tumor necrosis factor-alpha on human thyroid follicular cells.

Tumor necrosis factor-alpha is assumed to be an important mediator in thyroid autoimmunity. In the present study we have shown that human thyrocytes possess a single specific binding site for recombinant tumor necrosis factor-alpha with an average of 9,300 receptors/cell (Kd = 1.9 x 10(-10) mol). The effects of the cytokine on thyroid cell proliferation were assessed by 3H-thymidine uptake as well as by the protein and DNA content of cell monolayers. Low dose tumor necrosis factor-alpha resulted in a moderate stimulation of cell proliferation with an increase of 3H-thymidine incorporation from 44,613 +/- 7,989 cpm under basal conditions to 63,326 +/- 6,822 cpm after 100 U/l tumor necrosis factor-alpha (p < 0.01). Higher doses of the cytokine were less effective. On average, bTSH stimulated cAMP production of human thyrocytes was significantly augmented after preincubation with recombinant tumor necrosis factor-alpha. The maximum effect was observed after 1,000 U/l tumor necrosis factor-alpha (281.5 +/- 107.0 vs 114.5 +/- 33.6 fmol cAMP/micrograms protein under basal conditions: p < 0.05), whereas higher doses of the cytokine were again less effective. This phenomenon could at least partly be explained by a cytokine-mediated downregulation of tumor necrosis factor-alpha binding. We conclude that in vitro tumor necrosis factor-alpha modulates in addition to its well known synergistic effect on interferon-gamma induced HLA class II expression the function and proliferation of human thyroid follicular cells as well. These effects are mediated via specific cell surface receptors.     

The influence of tumor necrosis factor-alpha and interleukin-10 gene promoter polymorphism on the inflammatory response in experimental human endotoxemia.

In this study, we show that there is no correlation between tumor necrosis factor-alpha gene promoter polymorphism at position -308, interleukin-10 gene promoter polymorphism at position -1082, and the cytokine levels they produce in the human endotoxemia model.