肿瘤坏死因子-α对脊髓保护功能的电生理机制研究

目的：肿瘤坏死因子-α(TNF-α)具有脊髓保护功能，脊髓损伤后神经元Ca^2+通道开放加重钙超载导致细胞损伤，而TN-α与Ca^2+通道之间的直接关系尚未明确，为此研究TNF-α对大鼠脊髓背根神经节(DRG)感觉神经元细胞膜电压门控Ca^2+通道的电生理功能。方法：实验于2003-09／2004-01在华中科技大学同济医学院附属协和医院骨科实验室完成。实验采用酶解获得单个DRG细胞，采用标准全细胞膜片钳技术记录单一细胞分别在无药物干预和TNF-α10ng／L与μg／L条件下，依次给予单刺激，连续刺激和相关的双刺激时电压门控Ca^2+电流(ICa-L)．并分析对比电流形态、幅度、电流-电压曲线、最大电流的激活电压、反转电位和稳态灭活曲线形状的变化。结果：与用药前比较，TNF-α10ng／L和μg／L可显著性抑制ICa-L(P(0．01)，且两浓度间差异有显著性意义(P&;lt;0．01)；但TNF-α对ICa-L电流-电压(I-V)曲线的形状、峰电流对应的电位和反转电位无明显影响，加速稳态灭活过程。结论：TNF-α抑制ICa-L，可能是机体通过TNF-α对损伤脊髓发挥保护功能的机制之一。     

肿瘤坏死因子-α与脊髓损伤的研究进展

近年来,研究发现,肿瘤坏死因子-α(TNF-α)在急性脊髓损伤后炎症反应的发生中发挥着重要的作用。TNF-α可以上调其他炎性因子的产生,被认为是其他炎性因子的启动因子,参与损伤区炎症级联反应。本文就脊髓损伤后损伤区TNF-α的表达水平、介导的炎症信号通路以及不同浓度TNF-α的作用机制等方面进行综述。     

经皮电刺激对脊髓损伤大鼠脊髓前角神经营养因子-3及肿瘤坏死因子-α的影响

目的观察经皮电刺激对脊髓损伤大鼠脊髓灰质前角及损伤区神经营养因子-3（NT-3）和肿瘤坏死因子-α（TNF-α）表达的影响,并探讨经皮电刺激在脊髓损伤大鼠神经元重建及功能恢复中的作用机制。 方法共选取Wistar大鼠48只,采用随机数字表法将其分为模型组及电刺激组。采用Allen′s法将2组大鼠制成T9节段不完全脊髓损伤模型,电刺激组于术后给予经皮电刺激治疗。术后每天采用BBB评分对大鼠运动功能进行评定;2组大鼠分别于术后1 d、3 d、5 d及7 d时取材,采用免疫组化法观察2组大鼠在不同时间点脊髓中NT-3及TNF-α变化情况。 结果2组大鼠术后BBB评分均呈现增加趋势,并且以电刺激组的改善幅度较显著,该组大鼠BBB评分在术后5 d及7 d时均明显优于模型组(P<0.05);免疫组化检测结果显示,术后2组大鼠NT-3免疫阳性表达均持续增加,于术后5 d时达到峰值,于术后7 d时开始下降,并且电刺激组NT-3阳性表达量在术后5 d及7 d时均显著高于模型组(P<0.05);术后2组大鼠TNF-α免疫阳性表达均随时间进展而逐渐增多,但以电刺激组的增加幅度相对较缓,该组TNF-α免疫阳性表达在术后5 d及7 d时均显著低于模型组（P<0.05）。 结论经皮电刺激能促进脊髓损伤大鼠NT-3表达,抑制TNF-α表达增加,有助于脊髓损伤大鼠神经元修复、重建及相关功能恢复。     

亚低温对急性脊髓损伤后肿瘤坏死因子-α表达及运动功能恢复的影响

目的 观察大鼠脊髓损伤(SCI)后亚低温对肿瘤坏死因子-α (TNF-α)mRNA表达及运动功能恢复的影响,探讨其可能的作用机制.方法 72只SD大鼠随机分为对照组(n=24)、常温组(n=24)和亚低温组(n=24),每组再分为六个亚组,每亚组4只,参照改良Allen法建立大鼠脊髓(T9)中度损伤模型,亚低温组给予亚低温治疗5 h,而对照组不做亚低温处理.分别于损伤后6 h、12 h、24 h、72 h、1周和4周,利用 Tarlov评分检测亚低温对大鼠SCI后运动功能恢复的影响;然后将大鼠处死,利用半定量 RT-PCR方法观察损伤段脊髓组织中TNF-α mRNA表达的变化.结果 亚低温组TNF-α mRNA表达SCI后6~72 h明显少于常温组(P<0.05),而运动功能评分每个时间点都明显高于常温组(P<0.05).结论 亚低温可明显抑制SCI后TNF-α的表达,具有良好的恢复运动功能的作用.     

经皮电刺激对大鼠脊髓损伤后白细胞介素-1α、肿瘤坏死因子-α表达变化的影响

摘要 目的：探究经皮电刺激对大鼠脊髓损伤后白细胞介素-1α( IL-1α) 、肿瘤坏死因子-α(TNF-α) 表达变化的影响及意义。 方法：48只SD大鼠,随机分为对照组、电刺激组,采用改良Allen脊髓损伤打击模型,术后不同时间点采用BBB评分进行行为功能评估,用病理学和免疫组织化学方法定位、定性的检测对照组、电刺激组的损伤段脊髓组织中IL-1α、TNF-α的变化情况。 结果：BBB评分显示,术后第1—3天,对照组及电刺激组BBB评分值均为0—1分,电刺激组在损伤后第5天及第7天时BBB评分值与对照组相应时间点比较,组间差异明显(P<0.05);免疫组织化学显示,损伤后第1—7天,两组IL-1α、TNF-α免疫反应阳性神经元数目和平均积分光密度值强度呈递增趋势,且于第7天时达峰值,进一步分析得出,电刺激组IL-1α、TNF-α免疫反应阳性神经元数目及平均积分光密度值强度均明显低于对照组(P<0.05)。 结论：经皮电刺激可抑制脊髓损伤后IL-1α、TNF-α表达,减轻脊髓继发性炎症反应,促进功能恢复。     

肿瘤坏死因子对大鼠器官功能损伤的实验研究

将２１只大鼠随机分成肿瘤坏死因子作用２４ｈ组、７２ｈ组和生理盐水对照组。实验组用重组人的肿瘤坏死因子α型（ｒｈ－ＴＮＦ－α）×１０￣５Ｕ·ｋｇ￣（－１）／ｄ持续静脉泵入，分别于２４ｈ．７２ｈ活杀，观察血液及心、肝、肺、肾、肠组织ＴＮＦ水平；过氧化物歧化酶（ＳＯＤ）活性；丙二醛及血浆内毒素含量；组织超弱发光和白细胞吞噬发光、血气、肝肾功能及血培养情况。结果：实验２４ｈ组血浆ＴＮＦ显著升高，各脏器功能无明显受损，血培养及内毒素测定阴性、白细胞吞噬功能无变化；但ＴＮＦ可使血浆及组织氧自由基和脂质过氧化产物增加，全血ＳＯＤ活性下降。     

肿瘤坏死因子-α与血沉关系的实验研究

目的探讨肿瘤坏死因子-α(TNF-α)与红细胞沉降率(血沉,ESR)的关系。方法采用酶联免疫吸附测定(ELISA)法测定血清TNF-α及可溶性肿瘤坏死因子受体-Ⅰ(sTNFRⅠ)水平,采用魏氏法测定血沉;体外加入TNF-α、sTNFR-Ⅰ及sTNFR-Ⅱ后魏氏法测定血沉。结果肿瘤患者和糖尿病患者的血清TNF-α、sTNFR-Ⅰ水平及ESR值均显著高于正常对照组,且血清TNF-α、sTN-FR-Ⅰ水平与ESR值之间均有相关关系;ESR值愈大,血清TNF-α、sTNFR-Ⅰ水平愈高;体外加入TNF-α可以使ESR增快。结论TNF-α和sTNFR-Ⅰ与ESR之间存在相关关系,TNF-α和sTNFR-Ⅰ可以影响ESR。     

肿瘤坏死因子-α与原发性高血压的相关性研究

近年来流行病学研究证实肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)与急性冠脉综合征的发生密切相关。我们探讨TNF-α是否与原发性高血压(essential hypertension,EH)有关,为明确原发性高血压的发病机制提供新的依据。     

肿瘤坏死因子-α与胎膜早破

目的 探讨肿瘤坏死因子（TNF）-α在胎膜早破发病机制中的作用及意义。方法 采集无任何妊娠并发症、临产前要求剖宫产分娩的初产妇（包括19例足月胎膜早破、15例足月前胎膜早破和作对照的17例正常未破膜者）血、羊水及胎膜，用双抗体夹心酶联免疫吸附实验法测定血清、羊水中TNF-α的浓度，胎膜常规苏木素-伊红染色后行组织病理学检查及TUNEL技术精确标记后细胞凋亡指数的测定。结果 ①胎膜早破组血清、羊水中TNF-α浓度明显高于对照组，差异有显著性（P〈0.05或〈0.01）；且胎膜早破组胎膜感染的发生率和胎膜的细胞凋亡指数也较对照组高，差异有显著性（P〈0.05或〈0.01）；但足月和足月前胎膜旱破两组间血清、羊水中TNF-α浓度、胎膜感染率和细胞凋亡指数差异均无显著性（P〉0.05）。②胎膜有感染组血清、羊水中TNF-α浓度及胎膜细胞凋亡指数明显高于无感染组，差异有显著性（P〈0.01）；在无感染组中胎膜早破的血清、羊水中TNF-α浓度及胎膜细胞凋亡指数也较对照组高，差异有显著性（P〈0．01）。③所有研究对象血清、羊水中TNF-α浓度呈明显正相关（r=0．386，P〈0.01）。结论 TNF-α在胎膜早破发病机制中有促炎、降解细胞外基质、诱导细胞凋亡等功效；神经内分泌免疫网络失衡所致的胎膜细胞凋亡增加可能是胎膜早破的又一发病机制。     

肿瘤坏死因子-α在炎症与肿瘤中的作用

肿瘤坏死因子-α（TNF-α）主要是由脂多糖刺激巨噬细胞而分泌的一种蛋白质,具有多种生物活性的炎性细胞因子,与其他细胞因子共同作用参与激活免疫反应,介导全身炎症,诱发肿瘤的发生,并可致肿瘤坏死。TNF-α被认为与调节致病性休克、组织损伤和内毒素血症等相关;是所发现的抗肿瘤活性较强的炎性细胞因子,在炎症与肿瘤的发生发展中具有重要作用。     

脊髓损伤大鼠关节软骨转化生长因子β和肿瘤坏死因子α表达的变化

目的：观察脊髓损伤模型大鼠膝关节软骨组织中转化生长因子β和肿瘤坏死因子α的表达变化，分析其在软骨代谢变化中的意义，为关节软骨的修复重建方面提供理论基础。 方法：实验于2004-05／12在西安交通大学医学院骨病教研室完成。选择清洁级健康成年SD雌性大鼠36只，按随机数字表法分为脊髓损伤组和对照组，各18只。按改良Allen打击法建立大鼠脊髓中度损伤模型，对照组仅行T10椎板切除术。伤后1，3，6周麻醉下处死，两组每时间点均为6只。用AβC法进行转化生长因子β、肿瘤坏死因子α免疫组化染色及通过倒置光学显微镜及成像系统行灰度值扫描，对大鼠膝关节软骨组织中转化生长因子β、肿瘤坏死因子α的表达变化进行观察并采用SPSS 12．0软件对结果进行统计分析。 结果：脊髓损伤组在术后6d因泌尿系感染死亡1只，对照组组术后3d因硬膜外血肿死亡1只，后补齐进入结果分析大鼠36只。①免疫组化观察阳性表达信号为红色颗粒状，主要定位于胞浆和胞膜部位。肿瘤坏死因子α、转化生长因子β主要分布关节软骨表层中，阴性对照均呈现弱表达状态。②脊髓损伤后第1，3周时肿瘤坏死因子α阳性表达强度高于对照组（181．13&;#177;7．34，193．19&;#177;8．64；178．02&;#177;5．05，190．78&;#177;8．59；P〈0．05），第6周时与对照组比较，差异有非常显著性意义（175．56&;#177;6．05，192．98&;#177;8．26，P〈0．01）。③在脊髓损伤1周时转化生长因子β表达与对照组相比差异无显著性意义（P〉0．05），第3，6周时表达差异有显著性意义（182．25&;#177;4．73，191．40&;#177;6．87；176．85&;#177;7．68，191．41&;#177;8．53；P〈0．05）。 结论：脊髓损伤后肿瘤坏死因子α的表达具有时间上的早期性，转化生长因子β的表达则随着脊髓神经功能的恢复而增强，两者在第3周时关节软骨中表达均增强。     

脊髓损伤大鼠关节软骨转化生长因子β和肿瘤坏死因子α表达的变化

目的:观察脊髓损伤模型大鼠膝关节软骨组织中转化生长因子β和肿瘤坏死因子α的表达变化,分析其在软骨代谢变化中的意义,为关节软骨的修复重建方面提供理论基础。方法:实验于2004-05/12在西安交通大学医学院骨病教研室完成。选择清洁级健康成年SD雌性大鼠36只,按随机数字表法分为脊髓损伤组和对照组,各18只。按改良Allen打击法建立大鼠脊髓中度损伤模型,对照组仅行T10椎板切除术。伤后1,3,6周麻醉下处死,两组每时间点均为6只。用ABC法进行转化生长因子β、肿瘤坏死因子α免疫组化染色及通过倒置光学显微镜及成像系统行灰度值扫描,对大鼠膝关节软骨组织中转化生长因子β、肿瘤坏死因子α的表达变化进行观察并采用SPSS12.0软件对结果进行统计分析。结果:脊髓损伤组在术后6d因泌尿系感染死亡1只,对照组组术后3d因硬膜外血肿死亡1只,后补齐进入结果分析大鼠36只。①免疫组化观察阳性表达信号为红色颗粒状,主要定位于胞浆和胞膜部位。肿瘤坏死因子α、转化生长因子β主要分布关节软骨表层中,阴性对照均呈现弱表达状态。②脊髓损伤后第1,3周时肿瘤坏死因子α阳性表达强度高于对照组穴181.13±7.34,193.19±8.64;178.02±5.05,190.78±8.59;P<0.05雪,第6周时与对照组比较,差异有非常显著性意义(175.56±6.05,192.98±8.26,P<0.01)。③在脊髓损伤1周时转化生长因子β表达与对照组相比差异无显著性意义(P>0.05),第3,6周时表达差异有显著性意义穴182.25±4.73,191.40±6.87;176.85±7.68,191.41±8.53;P<0.05雪。结论:脊髓损伤后肿瘤坏死因子α的表达具有时间上的早期性,转化生长因子β的表达则随着脊髓神经功能的恢复而增强,两者在第3周时关节软骨中表达均增强。     

HSV-mediated transfer of interleukin-10 reduces inflammatory pain through modulation of membrane tumor necrosis factor alpha in spinal cord microglia

To dissect the molecular basis of the neuroimmune response associated with the genesis of inflammatory (nociceptive) pain, we constructed a herpes simplex virus-based gene transfer vector to express the antiinflammatory cytokine interleukin-10 (IL-10), and used it to examine the effect of IL-10 expression in activated microglial cells in vitro, and in inflammatory pain in vivo. IL-10 reduced the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and decreased the expression of full-length membrane spanning tumor necrosis factor-alpha (mTNFalpha) following lipopolysaccharide stimulation of microglia in vitro. IL-10 also reduced intracellular cleavage of mTNFalpha and release of the soluble cleavage product sTNFalpha. Similar effects on TNFalpha expression were observed when the cells were pretreated with a p38 MAPK inhibitor. In animals, injection of a dilute solution of formalin in the skin resulted in an increase in mTNFalpha in spinal dorsal horn, without detectable sTNFalpha. Local release of IL-10 achieved by gene transfer reduced the number of spontaneous flinches in the early and delayed phases of the formalin test of inflammatory pain. The effect of IL-10 on nocisponsive behavior correlated with a block in phosphorylation of p38 and reduced expression of 26 kDa mTNFalpha in spinal microglia. The results emphasize the key role played by membrane TNFalpha in the spinal neuroimmune response in pain caused by peripheral inflammation.     

Peripheral noxious stimulation reduces withdrawal threshold to mechanical stimuli after spinal cord injury: Role of tumor necrosis factor alpha and apoptosis

We previously showed that peripheral noxious input after spinal cord injury (SCI) inhibits beneficial spinal plasticity and impairs recovery of locomotor and bladder functions. These observations suggest that noxious input may similarly affect the development and maintenance of chronic neuropathic pain, an important consequence of SCI. In adult rats with a moderate contusion SCI, we investigated the effect of noxious tail stimulation, administered 1 day after SCI on mechanical withdrawal responses to von Frey stimuli from 1 to 28 days after treatment. In addition, because the proinflammatory cytokine tumor necrosis factor alpha (TNFα) is implicated in numerous injury-induced processes including pain hypersensitivity, we assessed the temporal and spatial expression of TNFα, TNF receptors, and several downstream signaling targets after stimulation. Our results showed that unlike sham surgery or SCI only, nociceptive stimulation after SCI induced mechanical sensitivity by 24 h. These behavioral changes were accompanied by increased expression of TNFα. Cellular assessments of downstream targets of TNFα revealed that nociceptive stimulation increased the expression of caspase 8 and the active subunit (12 kDa) of caspase 3, indicative of active apoptosis at a time point consistent with the onset of mechanical allodynia. In addition, immunohistochemical analysis revealed distinct morphological signs of apoptosis in neurons and microglia at 24 h after stimulation. Interestingly, expression of the inflammatory mediator NFκB was unaltered by nociceptive stimulation. These results suggest that noxious input caudal to the level of SCI can increase the onset and expression of behavioral responses indicative of pain, potentially involving TNFα signaling.     

Adeno-associated virus production of soluble tumor necrosis factor receptor neutralizes tumor necrosis factor alpha and reduces arthritis

The major limitation of adenovirus is its association with induction of an inflammatory response and relatively short-term production of the gene therapy transgene product. Adeno-associated virus (AAV) is a 4.68-kb single-strand DNA virus that contains ITRs for viral replication and a packaging signal, and also has been engineered to contain therapeutic genes up to 5 kb in length. Transduction of recombinant AAV (rAAV) results in low inflammatory response and long-term expression. We have cloned a low-immunogenic form of human sTNFRI (sTNFRI2.6D) into AAV (rAAVsTNFRI). This vector was analyzed for its ability to transfect and neutralize the effect of TNF-alpha on primary rheumatoid arthritis synovial fibroblast (RASFs). The rAAVsTNFRI was transduced into the cells at 1.8 x 10(1), 1.8 x 10(2), and 1.8 x 10(3) viral particles per cell. There was greater than 90% neutralization of TNF-alpha at 1.8 x 10(3) viral particles/cell. There was a significant decrease in the synovial cell hyperplasia and cartilage and bone destruction in human TNF-alpha transgenic mice treated intraarticularly with rAAVsTNFRI. These results indicate that the low-immunogenic and long-term expressing vector, rAAVsTNFRI, can be used to deliver the soluble TNF-alpha in vitro and in vivo and effectively reduce the severity of arthritis.     

Tumor suppression after tumor cell-targeted tumor necrosis factor alpha gene transfer

The tumor necrosis factor alpha (TNF-alpha) gene was introduced by retroviral gene transfer into the TNF-alpha-insensitive tumor cell line J558L. Production of 40 pg/ml TNF-alpha by clone J2T12 consistently did not change the growth rate in vitro, but drastically suppressed tumor growth when injected into syngeneic BALB/c mice. Within 2 wk, 90% of the mice inoculated with J558L cells developed a tumor, but none of the mice injected with J2T12 did so. Within the observation period (greater than 3 mo), 60% of the mice inoculated with J2T12 did not develop a tumor. In the other 40% of the mice, tumor manifestation was significantly delayed. Mice injected simultaneously with J2T12 cells and an anti-TNF-alpha monoclonal antibody developed tumors similar to parental J558L cells. Similarly, the tumor-suppressive effects of TNF-alpha were abolished, e.g., by injection of an anti-type 3 complement receptor (CR3) monoclonal antibody that is known to prevent migration of inflammatory cells. These results and the observation of tumor-infiltrating macrophages suggest that lack of tumorigenicity of J2T12 cells is due to the TNF-alpha secretion by the tumor cells and that TNF-alpha acts indirectly by a mechanism that involves chemotactic recruitment and activation of cells, predominantly of macrophages. In contrast, the tumor growth was not affected when, instead of TNF-alpha, interleukin 6 was expressed by J558L cells. Together, our results support the concept of tumor cell-targeted cytokine gene transfer as a tool for cancer treatment, and particularly demonstrate that extremely low doses of TNF-alpha produced by tumor cells are sufficient to inhibit tumor growth without detectable side effects.     

Fungal infections complicating tumor necrosis factor alpha blockade therapy

Tumor necrosis factor a (TNF-alpha) blockade has emerged as a useful therapy for collagen vascular diseases or graft-vs-host disease. Fungal infections complicating such therapy have been reported sporadically. MEDLINE and PubMed databases (from January 1, 1966, to June 1, 2007) were searched for reports of invasive fungal infections (IFIs) associated with the 3 available anti-TNF- alpha agents, ie, infliximab, etanercept, and adalimumab. Of the 281 cases of IFI associated with TNF-alpha inhibition, 226 (80%) were associated with infliximab, 44 (16%) with etanercept, and 11 (4%) with adalimumab. Fungal infections associated with infliximab occurred a median of 55 days (interquartile range [IQR], 15-140 days) after initiation of therapy and 3 infusions of the medication (IQR, 2-5), whereas those associated with etanercept occurred a median of 144 days (IQR, 46-240 days) after initiation of therapy. The median age of patients was 58 years (IQR, 44-68 years), and 62% were male. Use of at least 1 other immunosuppressant medication, typically a systemic corticosteroid, was reported during the course of the fungal infection in 102 (98%) of the 104 patients for whom data were available. The most prevalent IFIs were histoplasmosis (n=84 [30%]), candidiasis (n=64 [23%]), and aspergillosis (n equals 64 [23%]). Pneumonia was the most common pattern of infection. Of the 90 (32%) of 281 cases for which outcome information was available, 29 fatalities (32%) were recorded. Tumor necrosis factor a blockade is associated with IFI across a range of host groups. A high index of suspicion in patients treated with TNF-alpha antagonists is recommended because the course of such infections can be serious or fulminant, and rapid access to health care should be provided. Surveillance of IFIs complicating TNF-alpha blockade and other biologic therapies is warranted through well-organized prospective patient registries.     

Bruton's tyrosine kinase is required for lipopolysaccharide-induced tumor necrosis factor alpha production

Lipopolysaccharide (LPS), a product of Gram-negative bacteria, is potent mediator of tumor necrosis factor (TNF)alpha production by myeloid/macrophage cells. Inhibitors capable of blocking the signaling events that result in TNF alpha production could provide useful therapeutics for treating septic shock and other inflammatory diseases. Broad spectrum tyrosine inhibitors are known to inhibit TNF alpha production, however, no particular family of tyrosine kinases has been shown to be essential for this process. Here we show that the Bruton's tyrosine kinase (Btk)-deficient mononuclear cells from X-linked agammaglobulinemia patients have impaired LPS-induced TNF alpha production and that LPS rapidly induces Btk kinase activity in normal monocytes. In addition, adenoviral overexpression of Btk in normal human monocytes enhanced TNF alpha production. We examined the role of Btk in TNF alpha production using luciferase reporter adenoviral constructs and have established that overexpression of Btk results in the stabilization of TNF alpha mRNA via the 3' untranslated region. Stimulation with LPS also induced the activation of related tyrosine kinase, Tec, suggesting that the Tec family kinases are important components for LPS-induced TNF alpha production. This study provides the first clear evidence that tyrosine kinases of the Tec family, in particular Btk, are key elements of LPS-induced TNF alpha production and consequently may provide valuable therapeutic targets for intervention in inflammatory conditions.     

Stimulation of alpha 7 cholinergic receptors inhibits lipopolysaccharide-induced neutrophil recruitment by a tumor necrosis factor alpha-independent mechanism

The cholinergic nervous system controls inflammation by inhibiting the release of proinflammatory cytokines such as tumor necrosis factor (TNF) alpha from lipopolysaccharide (LPS)-stimulated macrophages. The key endogenous mediator of this so-called cholinergic anti-inflammatory pathway is acetylcholine, the principal neurotransmitter of the vagus nerve, which specifically interacts with alpha7 cholinergic receptors expressed by macrophages and other cell types to inhibit TNF-alpha production. We here investigated the capacity of the selective alpha7 cholinergic receptor agonist 3-(2,4-dimethoxybenzylidene) anabaseine (GTS-21) to inhibit LPS-induced inflammatory responses in mice in vivo. To this end, mice received an intraperitoneal injection of LPS (from Escherichia coli, 200 microg) preceded by GTS-21 (4 mg/kg) or vehicle. GTS-21 strongly inhibited LPS-induced TNF-alpha release into the peritoneal cavity and the circulation. In addition, GTS-21 attenuated the influx of neutrophils into peritoneal fluid upon administration of LPS. This inhibitory effect on neutrophil recruitment by GTS-21 was independent of its effect on TNF-alpha release, considering that etanercept, a potent TNF-alpha-blocking protein containing the extracellular domain of the p75 TNF-alpha receptor, did not influence LPS-induced neutrophil influx either in the presence or in the absence of GTS-21 treatment. GTS-21 did not reduce the local secretion of macrophage inflammatory protein 2 and keratinocyte-derived cytokine, suggesting that altered concentrations of these neutrophil-attracting chemokines did not contribute to GTS-21-induced inhibition of neutrophil migration. These data identify a novel anti-inflammatory effect of chemical alpha7 cholinergic receptor stimulation that is independent from its capacity to inhibit TNF-alpha production.     

Nonhematopoietic cells selected for resistance to tumor necrosis factor produce tumor necrosis factor

TNF-resistant lines of L cells can be derived from TNF-sensitive populations by repeated exposure to TNF, and these resistant L cells, in contrast to sensitive L cells and other types of cells, lack demonstrable cell surface receptors for TNF. We have now found that TNF-resistant L cells produce a factor that is cytotoxic for L cells and has the following distinguishing characteristics of mouse TNF: it is a protein of 43 kD, composed of 16 kD subunits, that competes with TNF for receptor binding, induces hemorrhagic necrosis of the TNF-sensitive mouse sarcoma Meth A, has synergistic cytotoxic action with interferon, and its activity is neutralized by antibody to TNF. The two conclusions of this study are that cells selected for TNF resistance spontaneously produce a molecule resembling macrophage TNF, and that cells of nonhematopoietic origin are capable of producing TNF.