TNF-α 在肿瘤中的作用

肿瘤坏死因子是一个特别的,并具有多重功能的细胞因子,它在免疫调节,炎症反应,机体防御当中起着关键的作用。根据不同的细胞微环境,肿瘤坏死因子可以诱导多种反应,例如凋亡,坏死,血管生成,免疫细胞激活,细胞分化,细胞迁移。TNF在肿瘤当中是一把双刃剑。一方面,TNF是一个内源性的肿瘤促进因素,因为TNF可以刺激肿瘤细胞生长,增殖,侵袭,转移,血管生成。另一方面,TNF具有杀肿瘤细胞的作用。因此,如果可以调控肿瘤坏死因子的功能,将为癌症的治疗提供可能。     

TNF-α作用的两面性

ＴＮＦ┐α作用的两面性细胞凋亡是否存在保护机制？最近Ｓｃｉｅｎｃｅ上发表了三篇文章从不同的角度证明,ＴＮＦ－α在诱导细胞凋亡的同时,可通过核因子κＢ（ＮＦ－κＢ）诱导某些蛋白以保护靶细胞免于死亡。因而,靶细胞的命运就取决于细胞内这两种机制的平衡。Ｂａ...     

TNF-α在癌症中的作用研究进展

肿瘤坏死因子-α（tumor necrosis factor-α,TNF—OL）是具有多种生物学效应的细胞因子。机体内适量的TNF-α在抵抗病原菌和肿瘤防御中起着重要的作用,但当其超过一定量时,TNF-α与其他炎性因子一起反而能促进癌症的发生发展及产生多种病理性损伤。就TNF-α在癌症中的双重作用及其临床研究现状作一综述。     

BDNF and TNF-α polymorphisms in memory

Here, we investigate the genetic basis of human memory in healthy individuals and the potential role of two polymorphisms, previously implicated in memory function. We have explored aspects of retrospective and prospective memory including semantic, short term, working and long-term memory in conjunction with brain derived neurotrophic factor (BDNF) and tumor necrosis factor-alpha (TNF-α). The memory scores for healthy individuals in the population were obtained for each memory type and the population was genotyped via restriction fragment length polymorphism for the BDNF rs6265 (Val66Met) SNP and via pyrosequencing for the TNF-α rs113325588 SNP. Using univariate ANOVA, a significant association of the BDNF polymorphism with visual and spatial memory retention and a significant association of the TNF-α polymorphism was observed with spatial memory retention. In addition, a significant interactive effect between BDNF and TNF-α polymorphisms was observed in spatial memory retention. In practice visual memory involves spatial information and the two memory systems work together, however our data demonstrate that individuals with the Val/Val BDNF genotype have poorer visual memory but higher spatial memory retention, indicating a level of interaction between TNF-α and BDNF in spatial memory retention. This is the first study to use genetic analysis to determine the interaction between BDNF and TNF-α in relation to memory in normal adults and provides important information regarding the effect of genetic determinants and gene interactions on human memory.     

TNF-α信号传导通路的分子机理

肿瘤坏死因子α（tumor necrosis factor-alpha,TNF-α）是一种具有多效生物学效应的细胞因子.TNF的生物学效应都是通过细胞表面的2种TNF受体（TNFR）引发,其信号传导通路主要包括caspase家族介导的细胞凋亡、衔接蛋白TRAF介导的转录因子NF-κB和JNK蛋白激酶的活化.TNFR1和TNFR2的生物学功能不是独立的,许多生物学活性由二者共同完成.3条信号传导通路之间及各通路内部含有各种调节机制,使TNF的各种生物学功能协调发挥出来.本文评述了3条信号传导通路最新进展、关键激酶的研究状况及其在整个信号网络中的作用机理,如IKK的激活以及重要的信号转导分子RIP、TRAF2、TRUSS的结构、相互作用的方式等     

Novel diarylheptanoids as inhibitors of TNF-α production

Synthesis and anti-inflammatory activity of novel diarylheptanoids [5-hydroxy-1-phenyl-7-(pyridin-3-yl)-heptan-3-ones and 1-phenyl-7-(pyridin-3-yl)hept-4-en-3-ones] as inhibitors of tumor necrosis factor-α (TNF-α) production is described in the present article. The key reactions involve the formation of a β-hydroxyketone by the reaction of substituted 4-phenyl butan-2-ones with pyridine-3-carboxaldehyde in presence of LDA and the subsequent dehydration of the same to obtain the α,β-unsaturated ketones. Compounds 4i, 5b, 5d, and 5g significantly inhibit lipopolysaccharide (LPS)-induced TNF-α production from human peripheral blood mononuclear cells in a dose-dependent manner. Of note, the in vitro TNF-α inhibition potential of 5b and 5d is comparable to that of curcumin (a naturally occurring diarylheptanoid). Most importantly, oral administration of 4i, 5b, 5d, and 5g (each at 100 mg/kg) but not curcumin (at 100 mg/kg) significantly inhibits LPS-induced TNF-α production in BALB/c mice. Collectively, our findings indicate that these compounds may have potential therapeutic implications for TNF-α-mediated auto-immune/inflammatory disorders.     

Sam68 guest STARs in TNF-α signaling

In this issue of Molecular Cell, Ramakrishnan and Baltimore (2011) identify Sam68 as a TNFR1 docking protein required for proper activation of TNF-α signaling.     

调节猪TNF-α表达的miRNAs鉴定

肿瘤坏死因子α(TNF-α)是脂肪细胞的分泌产物之一,在脂肪中行使着复杂的调节功能,为了研究猪脂肪组织中TNF-α的表达受到哪些miRNA的调控,从猪脂肪组织基因组中获得猪TNF-α3'端非翻译区(UTR)序列,与荧光素酶质粒PGL3-control连接构建猪TNF-α的萤光素酶表达质粒PGL3-TNF-α3'UTR。生物信息学预测miR-19a,miR-124,miR-130a,miR-301,miR-506等miRNAs均靶向猪TNF-α,将这些miRNA分别与PGL3-TNF-α3'UTR质粒共转到细胞中,以乱序序列作为阴性对照(NC),检测miRNA对质粒荧光素酶活性的作用。结果发现miR-19a,miR-124和miR-130a均能够显著抑制萤光素酶的活性(P0.01),为了验证这3个miRNA是否通过各自种子序列起调控作用,突变了PGL3-TNF-α3'UTR中这3个miRNA种子序列的结合位点,结果发现miRNAs对突变质粒中的荧光素酶均无明显抑制作用(P0.05)。结果证明,miR-19a,miR-124和miR-130a与猪TNF-α均有直接的靶向关系并通过各自种子序列抑制TNF-α的表达。     

Silencing of TNF-α receptors coordinately suppresses TNF-α expression through NF-κB activation blockade in THP-1 macrophage

Persistently elevated level of TNF-α has been implicated in several inflammatory disorders, however, its autocrine production through TNF-α receptors signaling is poorly understood. Here we report that simultaneous silencing of TNF-receptors, R1 and R2 by DNAzyme or siRNA suppressed TNF-α expression more efficiently than silencing them individually in lipopolysaccharides (LPS) stimulated THP-1 macrophages. Co-silencing of TNF-receptors also inhibited TNF-α induced NF-κB activation to a higher extent. It was further observed that NF-κB inhibitor but not c-Jun N-terminal kinase inhibitor (SP600125) suppressed TNF-α expression. All these results suggest that TNF-α expression is regulated by synergistic signaling of TNF receptors through downstream NF-κB activation.     

转TNF-α基因大肠杆菌培养条件的优化

目的：优化转pMD-489-TNF大肠杆菌的发酵条件,提高菌体产量及TNF-α产率。方法：通过单因素及正交实验,对影响转基因大肠杆菌生长及TNF-α表达的培养液成分、诱导剂浓度、培养温度等工艺条件进行了优化。结果：M9＋LB培养基成分的最优配比为3%葡萄糖、2%蛋白胨、4%酵母粉和1%NH4Cl,诱导剂IPTG浓度为0.5mmol/L,诱导时间4h,培养液初始pH是7.0,于37℃培养。结论：优化后的培养条件促进了菌体的生长和TNF-α的表达,菌体干重和TNF-α表达率比没有经过优化时升高了1.34倍和4.11倍,TNF-α产率从0.113%提高到0.479%,提高了324%。     

抗TNF-α单链抗体的表达及其纯化

克隆抗人肿瘤坏死因子(TNF-α)鼠源单抗的可变区基因以构建其单链抗体(ScFv)表达载体,实现在大肠杆菌的表达,并进行ScFv的可溶性纯化与鉴定。采用RT-PCR技术,以前导肽序列的引物从1个分泌抗人TNF-α的鼠单抗杂交瘤细胞系中克隆抗体轻链、重链可变区基因(VL,VH),构建ScFv基因,将ScFv基因片段与pGEX-4T-1表达载体连接,在大肠杆菌中表达并采用十二烷基肌氨酸钠(Sarkosyl)进行可溶性纯化,最后鉴定其生物活性。结果显示,得到了功能性重排的轻、重链可变区基因,分别构建了VH和VL不同连接顺序的HLL(VH-Linker-VL)和LLH(VL-Linker-VH)两种ScFv,LLH的表达量较HLL的高,但亲和力不及HLL。采用Sarkosyl溶解包涵体,对目的蛋白进行可溶性纯化,蛋白纯度达到90%,纯化后的蛋白经ELISA和WB证明ScFv维持了亲本抗体与TNF-α特异性结合的能力,且具有细胞毒中和活性。实验中研究探索了一种新颖的,操作简单,省时的裂解、纯化方案,实现了单链抗体经原核系统的表达后得以可溶性纯化。     

Nmp4促进TNF-α诱导的成骨细胞凋亡

核基质蛋白4(nuclear matrix protein4,Nmp4)是一种具有核质穿梭功能的结构性转录因子.主要通过负调控调节成骨细胞分化和增殖,抑制骨密度及骨量增加,而Nmp4是否调节成骨细胞凋亡,还未有相关报道.本课题通过分离Nmp4基因敲除(Nmp4-KO)和野生型(WT)小鼠原代成骨细胞,以肿瘤坏死因子(TNF-α)为凋亡诱导手段,研究了Nmp4对成骨细胞凋亡的影响及其作用机制.体外细胞实验发现,Nmp4-KO显著抑制TNF-α诱导的成骨细胞内caspase-3激活.Nmp4-KO促进细胞外信号调节激酶(Erk)和丝氨酸/苏氨酸蛋白激酶(Akt)信号途径的激活,抑制c-Jun氨基末端激酶(JNK)磷酸化,从而对抗成骨细胞凋亡.TNF-α诱导处理可增强成骨细胞核因子NFκB磷酸化及其核转位,但Nmp4基因缺失无进一步促进作用.未经诱导处理的Nmp4-KO细胞内NFκB磷酸化水平显著高于WT对照.此外,TNF-α诱导处理促使线粒体途径信号分子Bad磷酸化及Bcl-xl表达水平适当升高,但在两种细胞表型间无显著差异.这些结果证实,Nmp4基因敲除可促进相关抗凋亡信号分子的激活和表达,抑制促凋亡信号的激活,进而抑制成骨细胞凋亡的发生.     

TNF-α system and lung function impairment in obesity

A potential interaction between pulmonary function, abnormal adipose tissue activity, and systemic inflammation has been suggested. This study explores the relationship between circulating soluble TNF-α receptors (sTNF-R1 and sTNF-R2) and respiratory function parameters in obese subjects. Thirty-one non-diabetic morbidly obese women with a history of non-smoking and without prior cardiovascular or respiratory disease were prospectively recruited in the outpatient Obesity Unit of a referral center. Pulmonary function test included a forced spirometry, static pulmonary volume measurements, non-attended respiratory polygraphy, and arterial gas blood sampling. Circulating levels of sTNFR-R1, sTNF-R2, interleukine 6 and adiponectin were determined using ELISA. Statistical analysis included a multivariate regression analysis taking into account the potential confounders. sTNF-R1 positively correlated with BMI (r=0.571, p=0.001) and arterial carbon dioxide pressure (PaCO(2), r=0.381, p=0.038), but negatively with forced expiratory volume in 1s (FEV(1), r=-0.437, p=0.012), maximum midexpiratory flow (FEF(25-75), r=-0.370, p=0.040) and forced vital capacity (FVC, r=-0.483, p=0.005). However, no correlation between sTNF-R2 and BMI and either pulmonary function tests or arterial blood samples was observed. Multiple linear regression analysis showed that sTNF-R1 independently predicted FEV(1) (beta=-0.437, p=0.012) and FVC (beta=-0.483, p=0.005). Thus, circulating levels of sTNF-R1, but not sTNF-R2, are related to reduced lung volumes and airflow limitation in morbidly obese patients prior to the development of a clinically recognized respiratory disease. Therefore, studies addressed to evaluating the potential beneficial effect of anti-TNF-α agents on pulmonary function tests in obese subjects seem warranted.     

睡眠剥夺上调小鼠胰腺TNF-α的表达

目的探讨睡眠剥夺对小鼠胰腺形态、功能的影响以及肿瘤坏死因子-α(tumor necrosis factorα,TNF-α)表达变化的病理意义。方法 C57雄性小鼠随机分为正常对照组,睡眠剥夺24 h、48 h和60 h组,观察各组小鼠的精神活动状态及体重变化;检测血清淀粉酶(serum amylase,AMS)水平;采用HE染色和免疫组织化学法观察各组小鼠胰腺的组织学特征及TNF-α表达情况;Western Blot检测TNF-α的表达水平。结果随睡眠剥夺时间的延长,模型组小鼠体重较正常对照组明显下降。AMS水平在睡眠剥夺24 h显著升高,48 h达到峰值后维持至60 h。HE染色可见睡眠剥夺组小鼠出现胰岛细胞排列紊乱、胞质浓缩、细胞间隙扩大;外分泌部细胞酶原颗粒消失,细胞空泡化等病理改变;免疫组化及免疫印迹显示,睡眠剥夺组小鼠胰腺中TNF-α的表达随剥夺时间的延长而明显上调。结论睡眠剥夺后不仅导致小鼠全身衰竭,并通过活化TNF-α而诱导胰腺的炎症反应,导致其形态和功能损伤。     

TNF-α及其受体在格林巴利综合征中的作用

格林巴利综合征（Guillain-Barrésyndrome,GBS）是一种以周围神经和神经根的脱髓鞘及小血管周围淋巴细胞和巨噬细胞的炎性反应为病理特点的自身免疫性疾病。目前GBS的确切病因还不十分清楚,但是越来越多的研究表明,细胞因子在GBS的发生、发展过程中起到重要的作用,其中TNF-α及其受体在GBS的发病机制中更是扮演着重要的角色。本文就TNF-α及其受体在GBS发病过程中的作用进行综述。     

AMPK激活剂减轻TNF-α诱导的爆发性肝损伤

探讨腺苷酸活化蛋白激酶(AMP activated protein kinase,AMPK)激活剂A-769662对肿瘤坏死因子α(tumor necrosis factor alpha,TNF-α)诱导的爆发性肝损伤中肝细胞凋亡的影响及机制。本研究在雄性BALB/c小鼠经腹腔内注射肿瘤坏死因子α(tumor necrosis factor alpha,TNF-α)及D氨基半乳糖胺(D-galactosamine,D-Gal),诱导爆发性肝炎模型。实验分为4组:正常对照组、A-769662单独处理组、模型组和A-769662干预组。采用比色法检测血浆转氨酶活性及肝组织中caspase-8、caspase-9、caspase-3的相对活性,Western blotting法检测肝组织中激活型caspase-3蛋白水平,TUNEL法检测肝细胞凋亡,HE染色观察肝组织病理变化,并记录各组小鼠生存情况。A-769662干预抑制了TNF-α/D-Gal诱导的肝组织中caspase-8、caspase-9、caspase-3的活性和激活型caspase-3蛋白表达水平的升高,显著减少肝细胞凋亡数目,明显下调血浆中天冬氨酸氨基转氨酶(aspartate transaminase,AST)与丙氨酸氨基转氨酶(alanine transaminase,ALT)水平,减轻肝组织病理学改变,提高小鼠生存率。AMPK激活剂A-769662在TNF-α诱导的爆发性肝损伤中,可发挥抗凋亡保护效应,这可能是其在保肝效应的新机制。     

血清TNF-α与糖尿病微血管病变的关系

目的:研究肿瘤坏死因子α(tumor necrosis factor-alpha;TNF-α)与糖尿病微血管病变的关系.方法:将67例糖尿病患者,通过是否合并微血管痛变,分成无微血管病变组(DMI组)32例,合并微血管病变组(DM2组)35例,设正常时照组25例对比,用放射免疫法测得血清TNF-α,三组间进行比较.测受检者总胆固醇、甘油三酯、空腹血糖、糖化血红蛋白等指标,三组间比较.结果:2型糖尿病患者肿瘤坏死因子-α水平显著高于正常对照组(P＜0.01),糖尿病合并微血管病变组较糖尿病无微血管病变组其表达也明显升高(P＜0.01).结论:TNF-α表达的上调可能与糖尿病微血管病变的发生、发展关系密切     

两步串联层析法纯化抗TNF-α单克隆抗体

旨在建立从重组CHO细胞发酵培养液中纯化抗TNF-α单克隆抗体的两步串联层析法。将含有抗TNF-α单克隆抗体的料液经两次离心、一步过滤的预处理后,用protein A填料捕获,阳离子填料Sourec30精细纯化。精细纯化过程中利用Do E的方法,采用CCF(Central composite face)设计,探讨了洗脱p H值及盐浓度对纯化的影响。纯化后的抗TNF-α单克隆抗体经HPLC以及毛细管电泳,检测其浓度、纯度以及多聚体含量。结果显示,亲和层析的最佳洗脱条件为p H4.0。通过DOE优化,为达到质量目标(回收率90%以上,纯度97%以上,多聚体0.3%),筛选出最佳洗脱范围为0.05-0.13 mol/L Na Cl以及p H5.7-6.0,选定p H6.0与0.10mol/L Na Cl作为Source洗脱条件,此时回收率94.3%,纯度97.3%,多聚体0.3%,其质量与参比制剂接近。     

TNF-α在抑郁症中的作用和机制研究

抑郁症是一种情感精神疾病,临床上以显著而持久的心境低落为主要特征。抑郁症严重危害人们身心健康,降低生活质量,增加社会负担。抑郁的产生原因比较复杂,发病机制存在多种假说。在过去的几十年,虽然对于抑郁症的研究取得了一定的进展,但其确切的病因及病理生理机制目前仍不明确。近期,研究显示,促炎性细胞因子,尤其是肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)在抑郁症的发生、发展及临床药理机制中扮演着重要角色。现通过对TNF-α的生物学特征、在抑郁症发病和抗抑郁治疗中的作用、基因多态性与抑郁症关联性以及未来的应用与展望等进行综述,以期从多方面阐明TNF-α在抑郁症中的作用。