ERK信号转导途径在LPS诱导的人类内皮细胞iNOS表达中的作用

目的主要研究 p44/42MAPK(ERK1/2或ERK)信号途径在LPS诱导的人内皮细胞 -ECV304iNOS表达和NO产生中的作用。方法用Griess法检测细胞培养液中NO水平 ,分别用免疫荧光法和RT -PCR检测细胞iNOS蛋白和mRNA表达 ,采用免疫激酶沉淀以Westernblot检测细胞中ERK激酶的活性。结果LPS可显著激活人类内皮细胞 -ECV304中的ERK信号途径 ,其激活高峰在LPS刺激后15～20min ,45min后活性逐渐下降。用ERK的特异性抑制剂PD98059处理细胞后可以显著抑制LPS诱导人内皮细胞ERK的活性。与对照组相比 ,LPS刺激后的ECV304细胞iNOS蛋白和mRNA的表达明显增加 ,培养基中NO水平也显著升高 ,用PD98059预处理细胞后 ,可显著抑制细胞iNOS表达和NO和产生。研究结果表明ERK信号途径参与了LPS介导的人内皮细胞iNOS表达和NO产生。结论通过阻断信号转导通路来减少iNOS及其它细胞因子的产生 ,为败血症休克的防治提供了一条新的思路     

ERK在LPS诱导大鼠雪旺氏细胞TNF-α表达中的作用

目的 研究细胞外信号调节激酶（ERK）对脂多糖（LPS）诱导的大鼠雪旺氏细胞肿瘤坏死因子-α（TNF-α）表达的作用。方法 采用Westernblot检测细胞中ERK激酶的活性；用ERK的特异性抑制剂（PD98059）预处理细胞后，ELISA检测细胞中TNF-α水平；RT-PCR检测细胞中TNF-α mRNA的表达；用免疫荧光双标法检测ERK的表达定位。结果 LPS可显著激活雪旺氏细胞中的ERK信号通路，其激活高峰在LPS刺激后30～45min，60min后ERK磷酸化水平开始逐渐下降；用PD98059预处理细胞后，可显著抑制细胞TNF-α以及TNF-α mRNA的产生；LPS刺激细胞后引起ERK磷酸化，PD98059可抑制该过程。结论 ERK信号通路的激活可能是LPS诱导TNF-α表达的前提。通过阻断细胞内信号转导通路来减少TNF-α及其他细胞因子的产生，为抑制周围神经损伤后的炎症以及免疫反应发生提供了一条新的思路。     

乙型肝炎病毒X蛋白通过激活ERKs和NF-κB上调大鼠系膜细胞表达TNF-α

目的 探讨乙型肝炎病毒(HBV)X基因转染大鼠系膜细胞肿瘤坏死因子-α(TNF-α)高表达的细胞外蛋白调节激酶(ERKs)、核因子κB(NF-κB)、P38 MAPK信号传导机制.方法 将含有HBV X基因的质粒pCI-neo-X导入体外培养的大鼠系膜细胞,分别采用特异性抑制剂U0126阻断ERK1/2通路,Lactacystin阻断NF-κB通路和SB203580阻断P38 MAPK通路,观察培养细胞TNF-α及其mRNA表达,以不加抑制剂作为对照.RT-PCR检测TNF-α mRNA表达,ELISA检测培养上清液中TNF-α表达.Western blot检测乙型肝炎病毒X蛋白(HBx)表达.结果 转染pCI-neo-X后,系膜细胞TNF-α mRNA及上清液TNF-α表达均增高,通过阻断ERK1/2或NF-κB通路,细胞TNF-α mRNA及上清液TNF-α表达均下降.而阻断P38 MAPK通路对系膜细胞TNF-α mRNA及上清液TNF-α表达无明显影响.结论 HBx蛋白通过激活ERKs和NF-κB信号通路使系膜细胞高表达TNF-α,而与P38 MAPK通路无关.     

甜叶悬钩子苷通过NF-κB和MAPK信号通路抑制小鼠神经炎症细胞模型炎症反应

目的：通过体外实验探究甜叶悬钩子苷(RUB)对脂多糖(LPS)诱导小鼠BV-2小胶质细胞神经炎症反应的影响及改善机制。方法：采用CCK-8法检测RUB对BV-2细胞活力的影响;使用LPS诱导BV-2小胶质细胞建立神经炎症细胞模型,用不同浓度RUB进行干预,将BV-2细胞分为对照组、LPS模型组及LPS+RUB(25、50和100μmol/L)干预组,采用ELISA法检测细胞上清中白细胞介素1β(IL-1β)和肿瘤坏死因子α(TNF-α)的浓度;RTqPCR法检测促炎细胞因子环加氧酶2(COX-2)、诱导型一氧化氮合酶(iNOS)、IL-1β和TNF-α的mRNA表达水平;Western blot法检测NF-κB和MAPK信号通路相关蛋白的表达;免疫荧光染色观察细胞中p65的表达情况。结果：与对照组相比,LPS诱导后细胞上清液中IL-1β和TNF-α的分泌量增加(P<0.01),促炎细胞因子COX-2、iNOS、IL-1β和TNF-α的mRNA水平显著增加(P<0.01),NF-κB和MAPK信号通路蛋白表达显著上调(P<0.05或P<0.01),且p65出现荧光...     

GW4064 对LPS 诱导的RAW264.7 细胞中炎症反应的影响

目的:研究FXR激动剂GW4064对脂多糖(LPS)诱导的RAW264.7巨噬细胞炎症因子TNF-α、MCP-1和NO的分泌及IL-1β、TNF-α的表达,以及诱导型一氧化氮合酶(iNOS)表达的影响。方法:通过流式高通量多因子检测技术和Griess法检测炎症因子TNF-α、MCP-1和NO分泌的影响;采用qPCR技术检测炎症因子IL-1β、TNF-α和iNOS的mRNA的表达;Western blot检测iNOS及NF-κB蛋白的表达的水平。结果:GW4064能抑制LPS诱导的细胞促炎因子IL-1β、TNF-α和iNOS的mRNA的表达(P0.05),同时能不同程度的抑制细胞上清中TNF-α,MCP-1中的分泌量(P0.05);并且呈剂量依赖性的抑制NO的释放(P0.05);除此之外,GW4064(10、20μmol/L)可显著抑制LPS诱导的RAW264.7巨噬细胞iNOS蛋白的产生(P0.01),经过GW4064处理后,LPS诱导的RAW264.7巨噬细胞NF-κB的活性也显著下调(P0.01)。结论:FXR激动剂GW4064在巨噬细胞中具有一定的抗炎作用,抑制iNOS的表达及下调NF-κB的活性是其发挥抗炎作用的机制之一。     

尼古丁对脂多糖诱导的小胶质细胞激活及活化后细胞死亡的影响

目的 观察尼古丁对脂多糖(LPS)诱导的小胶质细胞激活及活化后细胞死亡的影响. 方法 建立慢性尼古丁暴露的小鼠动物模型,腹腔注射LPS诱导小胶质细胞激活,应用免疫组织化学方法 观察皮质、海马、黑质CD-11b阳性小胶质细胞表达的变化;BV2细胞(小鼠小胶质瘤细胞系)传代培养,运用CCK-8试剂盒检测细胞活性,一氧化氮检测试剂盒检测一氧化氮(NO)释放情况,RT-PCR分析诱导型一氧化氮合酶(iNOS)、肿瘤坏死因子(TNF-α)、白细胞介素1(IL-1β)、白细胞介素6(IL-6)、环氧化酶-2(COX-2)、干扰素调节因子1(IRF-1)、Caspase-11 mRNA的表达,免疫印迹法分析P-I-κB、Caspase-3的表达变化. 结果 尼古丁抑制LPS诱导的皮质、海马、黑质CD-11b阳性小胶质细胞的表达;尼古丁抑制LPS刺激引起的BV2细胞的死亡,NO的释放,iNOS、TNF-α、IL-1β、IL-6、COX-2、IRF-1、Caspase-11 mRNA的表达,P-I-κB、Caspase-3蛋白的表达. 结论 尼古丁可以抑制LPS诱导的小胶质细胞活化及激活诱导的细胞死亡(AICD),对脑内炎症反应具有神经保护作用.     

黄芪甲甙对大鼠LPS诱导原代培养多巴胺神经细胞的保护效应

目的:观察黄芪甲甙(AS-IV)对大鼠脂多糖(LPS)诱导多巴胺能细胞增殖的影响,检测炎症因子肿瘤坏死因子α(TNF-α)和诱导型一氧化氮合酶(iNOS)mRNA表达变化。方法:建立原代多巴胺细胞培养,加入LPS刺激,给予不同浓度AS-IV预处理。通过MTT方法检测多巴胺能细胞增殖情况,通过RT-PCR检测TNF-α、iNOSmRNA表达变化。结果:LPS刺激后多巴胺能细胞MTT值降低,经AS-IV预处理后MTT值升高。LPS刺激后TNF-α、iNOS mRNA表达上调;经AS-IV预处理后,TNF-α、iNOS mRNA表达明显下调(P<0.05)。结论:大鼠用AS-IV预处理可降低LPS对多巴胺能细胞毒性作用,提示AS-IV预处理可阻断LPS诱导多巴胺细胞变性和炎症变化,对中脑多巴胺能神经元具有保护性作用。     

p38MAPK在LPS诱导的小鼠肺组织诱导性一氧化氮合酶（iNOS） 表达中的作用

革兰氏阴性菌的脂多糖(LPS)在导致休克的同时,可以诱导多个器官和组织iNOS及一系列细胞因子的表达和产生,这些介质在休克发生发展过程中起着重要的作用.然而,参与休克过程的细胞和分子机制到目前为止仍属未知.目的观察LPS诱导小鼠肺组织iNOS表达的变化趋势及信号转导通路--p38丝裂原活化蛋白激酶(p38MAPK)在内毒素休克发生发展中的调控作用.方法1)用不同剂量的LPS对小鼠进行不同时间的处理,收集血液后处死小鼠,取肺组织,液氮速冻保存所有样本,采用Griess法检测血浆一氧化氮(NO)水平,分别用Westernblotting和RT-PCR检测肺组织iNOS蛋白和mRNA表达情况.2)复制内毒素休克模型,将戊巴比妥钠(60mg/kg)腹腔麻醉的BALB/c小鼠在立体分离显微镜(SMZ-1B,Nikon)下进行一侧颈动脉插管,与4道生理记录仪连接,记录血压.腹腔注射LPS(5mg/kg),记录血压变化及发生休克的时间.3)用p38MAPK特异性抑制剂SB203580(12.5mg/kg和25mg/kg,口服)对小鼠进行处理1h后,按前述方法复制休克模型,检测血浆NO水平,iNOS蛋白和mRNA的表达.结果1)未经LPS处理时,麻醉小鼠平均动脉压为(127.5±9.0)mmHg;LPS(5mg/kg)处理后小鼠动脉压呈现双峰型进行性下降,6h后平均动脉压降到(42.0±3.0)mmHg,导致重度休克.2)血浆硝酸盐和亚硝酸盐(一氧化氮,NO)的浓度,肺组织中iNOS蛋白及mRNA的表达以及肺组织湿重/干重比值,LPS处理组显著高于对照组.LPS处理4h后iNOS蛋白和mRNA表达,12-48h表达最显著;其中LPS剂量为20mg/kg时,在同一观察时间段与其他剂量组相比,iNOS的表达强度最大.3)经SB203580处理1h后,可以显著降低内毒素休克小鼠血浆NO水平和肺组织湿重/干重比值,并可显著抑制肺组织中iNOS蛋白和mRNA的表达,但是对血压下降并没有显著影响.结论1)LPS可诱导小鼠血浆一氧化氮(NO)水平升高,肺组织中iNOS蛋白和mRNA表达增加,并存在时间和剂量依赖性;2)p38MAPK信号转导通路可能在内毒素休克肺组织iNOS表达中起重要调节作用,提示可以通过抑制信号转导通路来降低iNOS表达及其它细胞因子的产生,可能对内毒素休克时组织损伤的防治有重要意义.     

Ghrelin 通过AKT/ ERK 信号通路对LPS 诱导的肺泡上皮细胞凋亡的影响

目的:研究Ghrelin 对内毒素(Lipopolysaccharide,LPS)所致的肺泡域型上皮细胞(A549)凋亡的影响及其机制。方法:CCK-8(Cell Counting Kit-8)法检测LPS 刺激对A549 的细胞毒性;原位末端标记法(TUNEL)检测细胞凋亡率;流式细胞术检测细胞内一氧化氮(NO)的产生;Western blot 检测诱导型一氧化氮合成酶(iNOS)、AKT、ERK、p-AKT、p鄄ERK 信号通路蛋白以及cleaved caspase-3、Bax、Bcl-2 凋亡相关蛋白的表达。结果:CCK-8 检测结果显示LPS 可显著抑制A549 细胞的增殖,降低细胞活力;TUNEL 检测发现Ghrelin 可显著抑制LPS 导致的A549 细胞的凋亡(P<0.05);LPS 可以促进iNOS 的表达,增加细胞内NO 的产生,并同时抑制AKT、ERK 通路的活性,上调下游促凋亡蛋白Bax 以及终末凋亡蛋白cleaved caspase-3 的表达,下调抗凋亡蛋白Bcl-2 的表达,而应用Ghrelin 预处理后可以逆转LPS 对AKT、ERK 通路活性的抑制,继而下调Bax 以及cleaved caspase-3 的表达,上调Bcl-2 的表达,差异均具有统计学意义(P<0.05),但Ghrelin 对细胞内NO 的产生无明显影响。结论:Ghrelin 可以通过上调AKT 及ERK 通路的活性抑制LPS 诱导的肺泡上皮细胞凋亡,但不能降低iNOS 诱导产生NO 的水平。     

锌离子螯合剂TPEN对脂多糖诱导的BV2细胞NF-кB P65、iNOS表达的影响

目的:观察锌离子螯合剂TPEN对脂多糖(LPS)刺激下小鼠BV2小胶质细胞核转录因子NF-кB P65亚基磷酸化及诱导型一氧化氮合酶(iNOS)mRNA表达的影响。方法:体外培养BV2细胞,用不同药物进行孵育,分组如下:正常对照组,单独LPS组,TPEN与LPS共处理组,NF-кB抑制剂BAY11-7082和LPS共处理组。采用实时荧光定量PCR法检测iNOS mRNA表达,Western Blot法检测磷酸化NF-кB P65(p-P65)蛋白表达。结果:TPEN浓度依赖性地减少LPS诱导的p-P65蛋白和iNOS mRNA表达,BAY11-7082浓度依赖性抑制LPS诱导的iNOSmRNA表达的上调。结论:TPEN能够减少LPS诱导的BV2细胞iNOS mRNA表达,该作用可能与其抑制NF-кB信号通路的激活有关。     

VIP对LPS应激的小鼠成纤维细胞TREM-2表达的影响及其机制

目的　观察血管活性肠肽（vasoactive intestinal peptide,VIP）对脂多糖（lipopolysaccharides, LPS）应激的小鼠成纤维细胞髓样细胞表达触发受体-2（TREM-2）表达的影响,并初步探讨其信号转导通路。 方法　利用LPS腹腔注射建立急性肺损伤（ALI）小鼠模型;采用VIP慢病毒气管滴注,qPCR检测肺组织TREM-2的表达。选用qPCR和流式细胞术检测VIP对LPS应激的小鼠成纤维细胞TREM- 2表达的影响;并观察PKC信号通路阻断剂（H-7）、PKA信号通路阻断剂（H- 89）、MAPK信号通路阻断剂（PD98059）和CaM信号通路阻断剂（W-7）对VIP调控TREM- 2表达的影响。 结果　ALI时小鼠肺组织TREM-2 mRNA表达降低,而VIP可上调肺组织TREM- 2 mRNA的表达。LPS下调小鼠成纤维细胞TREM- 2 mRNA的表达,VIP可呈时间依赖性上调TREM- 2 mRNA的表达（0、3 、6 、12和24 h）,且在6 h达到峰值;并呈剂量相关性上调TREM- 2 mRNA的表达（10-10、10-9、10-8和10-7 mol/L）,以10-8 mol/L作用最明显。VIP对LPS应激6 h增加小鼠成纤维细胞TREM-2 mRNA和蛋白表达的效应可被H-7、PD98059以及W- 7所阻断。 结论　LPS下调小鼠成纤维细胞TREM-2的表达,而VIP可上调LPS应激的小鼠成纤维细胞TREM- 2 mRNA的表达,其胞内信号转导途径可能与PKC、MAPK及CaM有关。     

Lipoteichoic acid induces nuclear factor-kappaB activation and nitric oxide synthase expression via phosphatidylinositol 3-kinase, Akt, and p38 MAPK in RAW 264.7 macrophages

We previously demonstrated that lipoteichoic acid (LTA) might activate phosphatidylcholine-phospholipase C (PC-PLC) and phosphatidylinositol-phospholipase C (PI-PLC) to induce protein kinase C activation, which in turn initiates nuclear factor-kappaB (NF-kappaB) activation and finally induces inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) release in RAW 264.7 macrophages. In this study, we further investigated the roles of tyrosine kinase, phosphatidylinositiol 3-kinase (PI3K)/Akt, and p38 mitogen-activated protein kinase (MAPK) in LTA-induced iNOS expression and NO release in RAW 264.7 macrophages. Tyrosine kinase inhibitors (genistein and tyrphostin AG126), PI3K inhibitors (wortmannin and LY 294002), and a p38 MAPK inhibitor (SB 203580) attenuated LTA-induced iNOS expression and NO release in concentration-dependent manners. Treatment of RAW 264.7 macrophages with LTA caused time-dependent activations of Akt and p38 MAPK. The LTA-induced Akt activation was inhibited by wortmannin, LY 294002, genistein, and tyrphostin AG126. The LTA-induced p38 MAPK activation was inhibited by genistein, tyrphostin AG126, wortmannin, LY 294002, and SB 203580. The LTA-induced formation of an NF-kappaB-specific DNA-protein complex in the nucleus was inhibited by wortmannin, LY 294002, genistein, tyrphostin AG126, and SB 203580. Treatment of macrophages with LTA caused an increase in kappaB-luciferase activity, and this effect was inhibited by tyrphostin AG126, wortmannin, LY 294002, the Akt dominant negative mutant (AktDN), and SB 203580. Based on those findings, we suggest that LTA might activate the PI3K/Akt pathway through tyrosine kinase to induce p38 MAPK activation, which in turn initiates NF-kappaB activation, and ultimately induces iNOS expression and NO release in RAW 264.7 macrophages.     

柚皮苷在促大鼠骨髓间充质干细胞骨向分化过程中对MAPK信号通路的影响

目的: 研究中药单体柚皮苷(NG)对体外培养的大鼠骨髓间充质干细胞(MSCs)向成骨细胞分化过程中MAPK信号通路的影响。方法: 观察在正常、加入p38、ERK和JNK通路抑制剂SB203580、PD98059、SP600125及3种抑制剂全部加入的情况下,各组碱性磷酸酶(ALP)、骨钙素(BGP)、I型胶原(Col I)等骨向分化指标的差异。用Western blotting技术检测各组p38、ERK1/2和JNK蛋白的磷酸化水平,用荧光定量PCR技术检测细胞因子转化生长因子β₁(TGF-β₁)、骨形成蛋白2(BMP-2)和核心结合因子α1(Cbfα1) mRNA的表达。结果: (1)10^-7mol/L为本实验中NG的最佳促骨向分化浓度。(2) NG最佳浓度组的ALP和BGP含量比其它各组都高(P<0.05),Col I含量无明显差异(P>0.05);与NG组相比,加入不同抑制剂组的ALP、BGP和ColⅠ表达量出现不同程度的降低。(3)与空白组相比,NG组JNK蛋白的磷酸化水平升高(P<0.05),p38蛋白的磷酸化水平降低(P<0.01),ERK1/2蛋白的磷酸化水平无明显差异(P>0.05)。与NG组相比,加入不同抑制剂组的p38、ERK1/2和JNK蛋白的磷酸化水平有升高也有降低。(4) NG组上调BMP-2的表达(P<0.05),下调Cbfα1的表达(P<0.05),而对TGF-β₁的表达无明显影响(P>0.05)。与NG组相比,加入不同抑制剂组的TGF-β₁、BMP-2和Cbfα1 mRNA表达量出现不同程度的降低。结论: NG主要通过激活MAPK信号通路中ERK通路、JNK通路以及上调BMP-2的表达,促进MSCs的骨向分化。NG上调BMP-2的表达受MAPK通路中p38通路的影响较大。     

Signalling mechanisms involved in the induction of inducible nitric oxide synthase by Lactobacillus rhamnosus GG,endotoxin, and lipoteichoic acid

Background and Aims: Probiotic Lactobacillus rhamnosus GG (Lactobacillus GG) has been found beneficial in the treatment of viral and antibiotic-associated diarrhea. Recently, it has also been shown to induce nitric oxide (NO) production, and have some other immunostimulatory effects. The aim of the present study was to investigate the mechanisms involved in the induction of inducible nitric oxide synthase (iNOS) and NO production by Lactobacillus GG. Methods and Results: iNOS expression and NO production induced by Lactobacillus GG, lipopolysaccharide (LPS), and lipoteichoic acid (LTA) was abrogated by NOS inhibitors L-NMMA and 1400W, by a protein synthesis inhibitor cycloheximide, by a tyrosine kinase inhibitor genistein and by a NF-B inhibitor pyrrolidinedithiocarbamate (PDTC) in J774 macrophages. Polymyxin B inhibited NO production induced by LPS, but did not inhibit Lactobacillus GG induced NO production. _P42/44 MAP-kinase inhibitor PD98059, dexamethasone and cyclosporine A inhibited partially iNOS protein expression and NO formation in LactobacillusGG, LPS and LTA treated cells. Ro 31-8220 (protein kinase C inhibitor) and SB203580 (p38 MAP-kinase inhibitor) had only a minor effect on NO production. Conclusions: Lactobacillus GG induced NO production through iNOS pathway and the mechanisms mediating that process were very similar with those involved in LPS and LTA induced NO synthesis.     

Possible pathophysiological roles of mitogen-activated protein kinases (MAPKs) in endometriosis

PROBLEM: Endometriosis accompanies local inflammatory reactions in the peritoneal cavity. We examined the phosphorylation of mitogen-activated protein kinases (MAPKs), i.e. extracellular signal-regulated kinase (ERK), p38 MAPK (p38) and c-Jun N-terminal kinase (JNK) in endometriotic stromal cells, and their possible pathophysiological roles in endometriosis in relation to proinflammatory substances. METHOD OF STUDY: Endometriotic stromal cells were isolated from endometriomas and were cultured for the experiments. Phosphorylation of MAPKs in endometriotic stromal cells treated with interleukin (IL)-1beta, tumor necrosis factor (TNF)alpha and H(2)O(2) were examined by Western blot analysis. Effects of PD98059, SB202190 and SP600125 (inhibitors of ERK, p38 and JNK, respectively) on IL-1beta-induced secretion of IL-6 and IL-8, and on IL-1beta-induced expression of cyclo-oxygenase-2 (COX-2) in endometriotic cells were studied. In addition, eutopic endometrial tissues were collected, and the phosphorylation rate of p38 in eutopic endometrial tissues and endometriotic tissues were determined. RESULTS: IL-1beta, TNFalpha and H(2)O(2) stimulated the phosphorylation of ERK, p38 and JNK, while the total amounts of proteins of the respective MAPKs were virtually the same compared with those in the unstimulated controls. Both SB202190 and SP600125 suppressed IL-1beta-induced secretion of IL-6 and IL-8, and PD98059 suppressed IL-1beta-induced secretion of IL-8. Both SB202190 and PD98059 suppressed IL-1beta-induced expression of COX-2 in endometriotic cells. The p38 phosphorylation rates in the endometriotic tissues were significantly higher than those in the eutopic endometrial tissues of the same patients. CONCLUSIONS: Given the current theory that inflammatory changes are involved in the progression of endometriosis, MAPKs could play as pivotal intracellular signal transducers in endometriotic cells, and thus have a pathophysiological role in the disease.     

Bacterial endotoxin stimulates macrophages to release HMGB1 partly through CD14- and TNF-dependent mechanisms

Bacterial endotoxin [lipopolysaccharide (LPS)] stimulates macrophages to sequentially release early [tumor necrosis factor (TNF)] and late [high mobility group box 1 (HMGB1)] proinflammatory cytokines. The requirement of CD14 and mitogen-activated protein kinases [MAPK; e.g., p38 and extracellular signal-regulated kinase (ERK)1/2] for endotoxin-induced TNF production has been demonstrated previously, but little is known about their involvement in endotoxin-mediated HMGB1 release. Here, we demonstrated that genetic disruption of CD14 expression abrogated LPS-induced TNF production but only partially attenuated LPS-induced HMGB1 release in cultures of primary murine peritoneal macrophages. Pharmacological suppression of p38 or ERK1/2 MAPK with specific inhibitors (SB203580, SB202190, U0126, or PD98059) significantly attenuated LPS-induced TNF production but failed to inhibit LPS-induced HMGB1 release. Consistently, an endogenous, immunosuppressive molecule, spermine, failed to inhibit LPS-induced activation of p38 MAPK and yet, still significantly attenuated LPS-mediated HMGB1 release. Direct suppression of TNF activity with neutralizing antibodies or genetic disruption of TNF expression partially attenuated HMGB1 release from macrophages induced by LPS at lower concentrations (e.g., 10 ng/ml). Taken together, these data suggest that LPS stimulates macrophages to release HMGB1 partly through CD14- and TNF-dependent mechanisms.