p38 MAPK- Pim-3通路可能介导预处理对抗心肌细胞缺氧/复氧损伤

目的： 研究MAPK通路在原癌基因Pim-3抗心肌急性缺氧复氧损伤中的作用。方法：采用原代培养新生大鼠的心肌细胞,随机分为4组：正常对照组（control）、缺氧复氧组(A/R)、缺氧预适应组(APC+A/R)、阻断剂组。在缺氧预处理前分别用终浓度为10 μmol/L SB203850(p38 MAPK阻断剂)、U0126（ERK1/2阻断剂）、SP600125（SAPK/JNK阻断剂）与细胞孵育30 min。实验结束后测定MAPKs通路中ERK1/2、JNK、p38 MAPK 磷酸化蛋白表达水平及Pim-3蛋白的表达水平,同时检测培养液中乳酸脱氢酶(LDH) 活性、四唑盐（MTT）比色试验测定细胞存活率、TUNEL法检测细胞凋亡。结果： SB203850、U0126、SP600125能分别取消由APC或A/R所诱导ERK1/2、JNK、p38 MAPK的磷酸化水平的升高;由APC所诱导的Pim-3表达的升高在p38 MAPK通路被阻断后明显下调(P<0.01),并且心肌细胞LDH值升高,细胞存活率则下降,心肌细胞的凋亡指数升高。结论： p38 MAPK的激活可上调原癌基因Pim-3的表达,从而可能对心肌细胞起到保护作用。     

CPSIT_p7通过激活JNK/ERK信号通路诱导宿主细胞炎症

目的初步探讨鹦鹉热嗜衣原体蛋白CPSIT_p7对宿主细胞炎症反应的调节作用及其分子机制。方法佛波酯(PMA)处理THP-1细胞过夜,诱导其分化为贴壁的巨噬细胞,之后用CPSIT_p7蛋白刺激贴壁细胞,或先用30μmol/L ERK抑制剂PD98059、JNK抑制剂SP600125和p38抑制剂SB202190分别预处理贴壁细胞,再用CPSIT_p7蛋白处理贴壁细胞;Western blot检测ERK、JNK和p38磷酸化水平,ELISA检测各种炎症因子的表达水平。结果 0~10μg/ml CPSIT_p7蛋白刺激PMA诱导的THP-1细胞24 h后,随着CPSIT_p7质量浓度升高,IL-6、IL-1β、IL-8及TNF-α的含量呈剂量依赖性增加;10μg/ml的CPSIT_p7处理细胞0、6、12、24和36 h,在24 h时IL-6、IL-8及IL-1β表达水平达到高峰,而TNF-α在12 h就达到高峰;CPSIT_p7蛋白处理细胞后其ERK和JNK磷酸化水平显著升高,p38磷酸化水平改变不明显;JNK和ERK抑制剂能明显降低CPSIT_p7蛋白诱导的IL-6、IL-1β、IL-8及TNF-α表达。结论 CPSIT_p7通过JNK/MAPKs和ERK/MAPKs信号传导途径诱导THP-1产生IL-1β、IL-6、IL-8及TNF-α炎症因子,与p38/MAPKs信号传导通路无关。     

p38MAPK参与千金藤素诱导的心肌细胞凋亡

目的: 探讨千金藤素(CEP)致Sprague-Dawley(SD)乳大鼠心肌细胞的凋亡作用及其信号途径。方法: 应用MTT法检测千金藤素对心肌细胞活性的抑制作用;利用Hoechst 33342染色及Western blotting方法检测凋亡相关信号分子caspase-3,观察CEP致心肌细胞凋亡的作用;采用Western blotting法观测 CEP对有丝分裂原活化蛋白激酶(MAPKs)家族3个主要信号分子c-Jun氨基端激酶(JNK)、细胞外信号调节激酶(ERK)、p38 MAPK磷酸化水平的影响,并利用ERK和p38 MAPK的特异性抑制剂,分别验证两种分子所介导的信号通路在CEP致心肌细胞凋亡中的作用。结果: (1)CEP能够剂量依赖和时间依赖地抑制心肌细胞的活性。(2)CEP作用于心肌细胞,出现细胞核碎裂现象和caspase-3激活。(3)CEP作用下p38 MAPK和ERK磷酸化水平显著增强,JNK的磷酸化状态未发生显著改变。(4)p38 MAPK磷酸化抑制剂SB203580显著减轻CEP对心肌细胞活性的抑制作用;ERK磷酸化抑制剂PD98059不能影响CEP对心肌细胞活性的抑制作用。结论: p38 MAPK参与CEP致心肌细胞凋亡作用。     

TGF-β1激活的p38MAPK在TGF-β1上调人卵巢癌细胞PAI-1表达中的作用

目的:纤溶酶原激活物抑制剂1(PAI-1)在凝血、创伤修复、炎症和肿瘤转移中起重要作用。已有报道转化生长因子β1(TGF-β1)能通过Smad通路诱导PAI-1表达,但TGF-β1能否通过激活非Smad通路诱导PAI-1表达尚不清楚,因此本研究探讨了在卵巢癌细胞中TGF-β1激活的非Smad通路p38丝裂原活化蛋白激酶(p38MAPK)和细胞外信号调节激酶(ERK)与TGF-β1上调PAI-1表达的关系。方法:用10μg/L TGF-β1处理卵巢癌SKOV3细胞和HO-8910细胞后,采用real-time PCR和Western blotting的方法检测PAI-1的表达,用磷酸化p38MAPK的抗体和磷酸化ERK的抗体检测p38 MAPK和ERK的激活情况,用p38 MAPK和ERK的特异性抑制剂SB203580和PD98059分别抑制其活性后,检测PAI-1的表达。结果:TGF-β1在卵巢癌细胞中可明显上调PAI-1mRNA和蛋白的表达,并可快速激活p38 MAPK和ERK。用p38 MAPK的抑制剂可以明显抑制TGF-β1上调PAI-1表达,但是抑制ERK活性对TGF-β1上调PAI-1表达没有明显影响。结论:TGF-β1激活的p38 MAPK通路参与了TGF-β1上调PAI-1的表达。     

MAPKs在anti-β2GPI/β2GPI刺激THP-1细胞表达TF过程中的作用探讨

目的:探讨丝裂原活化蛋白激酶(Mitogen-activated protein kinases,MAPKs)在anti-β2 GPI/β2 GPI复合物诱导单核细胞株THP-1表达组织因子(TF)中的活化及其作用。方法:利用荧光定量PCR(Real-time PCR)、TF活性试剂盒等分别检测anti-β2 GPI/β2 GPI复合物诱导THP-1细胞表达TF mRNA及TF活性,Western blot检测细胞表达p38、磷酸化-p38(p-p38)、ERK1/2、磷酸化-ERK1/2(p-ERK1/2)、JNK、磷酸化-JNK(p-JNK)的情况。进一步采用p38、ERK1/2、JNK抑制剂(SB203580、U0126、SP600125)观察是否能阻断anti-β2 GPI/β2 GPI复合物诱导THP-1细胞表达TF。结果:Anti-β2 GPI/β2 GPI复合物(100μg/ml)能够显著增强THP-1细胞表达TF,并使p-p38、p-ERK1/2、p-JNK水平显著升高(P<0.05 vs control);其引发的MAPKs磷酸化具有时间效应性,均在刺激30分钟时达到高峰;对应的特异抑制剂SB203580(10μmol/L)、U0126(5μmol/L)、SP600125(90 nmol/L)单独或合并处理THP-1细胞后,anti-β2 GPI/β2 GPI复合物诱导细胞TF mRNA表达及TF活性的效应明显被阻断(P<0.01 vs control)。结论:Anti-β2 GPI/β2 GPI复合物诱导THP-1细胞表达TF过程中,MAPKs被激活进而发挥重要作用。     

MAPK和caspase-3在异基因CD8+T淋巴细胞诱导血管内皮细胞凋亡中的作用

目的： 探讨MAPK和caspase-3在异基因CD8+T细胞诱导血管内皮细胞凋亡中的作用。方法：免疫磁珠阳性分选异基因CD8+T细胞,AnnexinⅤ/FITC试剂盒检测异基因CD8+T细胞诱导的HUVECs和HDMECs凋亡率,Western blotting检测血管内皮细胞内caspase-3、MAPK表达。观察SB203580 (p38MAPK抑制剂)、SP600125 (JNK抑制剂)、PD98059（ERK抑制剂）、Z-DEVD-FMK（caspase-3抑制剂）对内皮细胞凋亡的影响。结果：异基因CD8+T细胞作用24 h和48 h后,HUVECs凋亡率分别为41.7％±10.1％和29.4％±8.3％,HDMECs凋亡率分别为28.9％±7.2％和15.2％±4.8％,与对照组相比均具有显著差异（P<0.01）。异基因CD8+T细胞作用后,HUVECs和HDMECs内磷酸化p38MAPK表达、caspase-3裂解增强,而磷酸化JNK、ERK无明显变化。Z-DEVD-FMK和SB203580可显著抑制异基因CD8+T细胞诱导的HUVECs和HEMEC凋亡,并降低内皮细胞caspase-3表达。结论：p38MAPK和caspase-3介导了异基因CD8+T细胞诱导的血管内皮细胞凋亡。     

LPS诱导胰腺癌细胞Panc-1表达B7-H1

目的: 研究胰腺癌细胞株Panc-1在应用脂多糖(LPS)刺激前后B7-H1表达的变化,并探讨其可能的分子机制。方法: LPS刺激以及丝裂原活化蛋白激酶(MAPKs)的特异性抑制剂处理Panc-1细胞前后,应用Western blotting检测MAPKs信号通路中p38丝裂原活化蛋白激酶(p38)、细胞外信号调节蛋白激酶(ERK)和c-Jun氨基端激酶(JNK)磷酸化水平的变化,real-time PCR和Western blotting检测B7-H1 mRNA和蛋白的表达变化。结果: LPS刺激后B7-H1的表达显著上调,p38、ERK和JNK的磷酸化水平也明显上调,加入MAPKs特异性的抑制剂后,LPS诱导的p38、ERK和JNK的磷酸化被抑制,并且在p38和ERK的抑制剂处理后,B7-H1的表达也明显被抑制,而在JNK的抑制剂处理后B7-H1的表达没有显著变化。结论: LPS可以诱导胰腺癌细胞株Panc-1表达B7-H1,并且p38和ERK的活化在LPS诱导的B7-H1的表达过程中起着重要作用。     

p38 MAPK信号通路参与受体介导的细胞内吞的调控

目的：观察p38 MAPK信号转导通路在受体介导的细胞内吞中的作用。方法：利用Alexa 594标记的转铁蛋白作为受体介导的内吞作用的观察指标，来研究p38特异性抑制剂SB203580或ERK通路特异性抑制剂PD98059预处理以及p38基因敲除对该过程的影响。 结果：在受体介导的细胞内吞中，p38被磷酸化激活。SB203580的预处理或p38基因的敲除都能阻断受体介导的细胞内吞，而PD98059的预处理对该过程没有影响。 结论：p38 MAPK信号转导通路参与了受体介导的细胞内吞的调控。     

MAPK和NF-κB上调脂多糖诱导的小鼠肺微血管内皮细胞Toll-like受体4的表达

目的观察MAPK和NF-κB在经脂多糖(LPS)诱导的小鼠肺微血管内皮细胞(PMVECs)Toll-like受体4(TLR4)表达增强中的作用。方法分离培养PMVECs。不同浓度的LPS与PMVECs共培养2 h,或与LPS(100μg/L)作用不同时间。用ELISA法检测培养上清液中TNF-α含量。分别用ERK抑制剂PD98059和P38MAPK抑制剂SB203580或NF-κB抑制剂PDTC进行干预。用反转录聚合酶链反应(RT-PCR)检测TLR4和TNF-αmRNA。用W estern-b lot检测ERK/P38 MAPK和核蛋白NF-κB的表达。结果在LPS浓度为50~500μg/L时,作用于PMVECs 2 h,或LPS 100μg/L作用不同时间时,培养上清液中TNF-α含量呈剂量和时间依赖性显著增加(P<0.01)。PMVECs表达TNF-α及TLR4 mRNA增加,6 h时达高峰。分别用上述抑制剂均可缓解上述变化,而同时联合使用PD98059和SB203580则进一步增强该抑制作用。上述抑制剂分别缓解LPS诱导的PMVECs表达ERK/P38 MAPK和NF-κB蛋白增强。结论MAPK和NF-κB上调给脂多糖诱导的小鼠PMVECs TLR4的表达。     

肺炎克雷伯菌夹膜多糖激活AP-1 诱导人支气管上皮细胞表达 β-防御素-3

目的:观察肺炎克雷伯菌夹膜多糖(CPS)对人支气管上皮细胞表达β-防御素-3(hBD-3)的影响,并探讨其作用机制。方法:用肺炎克雷伯菌CPS刺激人支气管上皮细胞BEAS-2B。使用实时定量PCR和ELISA分别检测hBD-3 mRNA和蛋白表达的影响。测定CPS处理前后丝裂原活化蛋白激酶(MAPKs)以及c-Jun的磷酸化。采用MAPKs和NF-κB抑制剂或RNA干扰TLR4表达,观察其在介导hBD-3表达中的作用。采用染色质共沉淀技术检测核转录因子AP-1与hBD-3启动子的结合情况。结果:CPS处理细胞后,hBD-3 mRNA的表达呈剂量依赖性升高,ELISA获得类似结果。CPS能激活MAPKs,采用p38、ERK及NF-κB抑制剂SB203580、PD98059和PDTC处理细胞后,不影响hBD-3的表达,而JNK抑制剂SP600125处理后,hBD-3分泌明显降低。CPS可诱导AP-1亚基c-Jun磷酸化及能增强AP-1与hBD-3启动子的结合。结论:肺炎克雷伯菌夹膜多糖激活AP-1诱导人支气管上皮细胞表达β-防御素-3。     

尿酸诱导树突状细胞成熟的信号转导机制研究

目的: 观察树突状细胞(DCs)成熟过程中MAPKs和NF-κB信号分子表达情况,探讨尿酸刺激DCs成熟的分子机制。方法: 用尿酸体外刺激大鼠未成熟 DCs,在不同时点(0~45 min),免疫印迹方法检测p- p38、p-ERK1/2、p-JNK和NF-κB p65表达情况;以MAPKs和NF-κB信号分子抑制剂分别联合尿酸刺激DCs 48 h后,用流式细胞术检测表面分子CD83、CD86、IA/IE的表达;ELISA法测定IL-12 p70的水平。结果: (1)尿酸刺激后15 min,DCs p- p38、p-ERK1/2、p-JNK和NF-κB p65表达量明显增加,30 min时达到最大值;使用相应信号分子抑制剂后,相关蛋白表达均不能测出。(2)经p38、JNK、NF-κB p65等信号通路抑制剂预处理后,与单独尿酸刺激相比,DCs CD83、CD86、IA/IE等表面分子表达及IL-12 p70分泌水平均出现下降(P＜0.05或P<0.01),ERK1/2抑制剂预处理者,则出现表达上升(P＜0.05)。结论: 尿酸可以调节DCs p38、ERK1/2、JNK、 NF-κB等信号分子的活化,从而促进DCs表面分子表达及IL-12 p70分泌。这可能为尿酸能诱导DCs成熟及提高免疫功能的分子机制之一。     

Close association of p38 and JNK with plasminogen-dependent upregulation of PAI-1 in rat astrocytes in vitro

As reported previously, stimulation of astrocytes with plasminogen (PLGn) remarkably enhances their production/release of plasminogen activator inhibitor-1 (PAI-1). In addition, both p38 mitogen-activated protein kinase (p38MAPK) and c-Jun N-terminal kinase (JNK) are activated in these astrocytes. However, it remains to be determined whether the MAPK activation is associated with the PAI-1 induction in PLGn-stimulated astrocytes. In the present study, we investigated the relationship between MAPK activity and PAI-1 induction in PLGn-stimulated astrocytes. PLGn stimulation led to definitive phosphorylation of three MAPKs: external signal regulated kinase (ERK), JNK and p38. These results suggest that all of these MAPKs, either alone or in combination, are involved in PAI-1 induction. To verify this association, an inhibition experiment was carried out by using inhibitors specific for each MAPK. The results of the immunoblotting analysis indicated that 20 μM SB203580 (the p38 inhibitor) or SP600125 (the JNK inhibitor) suppressed approximately 85% or 40% of PLGn-inducible PAI-1, respectively. Only 20% inhibition was achieved by pretreatment of astrocytes with 20 μM PD98059 (the inhibitor of MEK1/2, an upstream kinase of ERK). In conclusion, p38 and JNK were shown to be the major MAPKs involved in the signaling cascade leading to PAI-1 induction in astrocytes stimulated with PLGn.     

Role of c-Jun N-terminal kinase on lipopolysaccharide induced maturation of human monocyte-derived dendritic cells

Dendritic cells (DCs) are potent antigen-presenting cells that play a pivotal role in the initiation of T cell-dependent immune responses. Immature DCs obtained from peripheral blood CD14+ monocytes by culture with granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin-4 (IL-4) differentiate into mature DCs upon stimulation with lipopolysaccharide (LPS). At least three families of mitogen-activated protein kinases (MAPKs), that is, extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK) and p38 MAPK, are involved in the DC maturation process. We report investigations of the role of JNK in the maturation of human monocyte-derived DCs. SP600125, a specific inhibitor of JNK, inhibited the LPS-induced up-regulation of CD80, CD83, CD86 and CD54, but augmented the up-regulation of HLA-DR. SP600125 slightly inhibited the down-regulation of FITC-dextran uptake during DC maturation. However, SP600125 did not affect the LPS induced up-regulation of allostimulatory capacity of DCs. SP600125 inhibited the release of IL-12 p70 and TNF-alpha from mature DCs. Although autologous T cells primed by the ovalbumin (OVA)-pulsed mature DCs produced IFN-gamma, but not IL-4, OVA-pulsed SP600125-treated mature DCs could initiate IL-4 production from autologous T cells. In contrast, a p38 MAPK inhibitor, SB203580, profoundly inhibited the phenotypic and functional maturation of DCs, while an ERK inhibitor, PD98059, had little or no effect. Taken together, the JNK signaling pathway appears to have a role that is distinct from the p38 MAPK and ERK cascades in the maturation process of DCs, and may be involved in the augmentation of Th2-prone T cell responses when it is suppressed.     

Place preference induced by nucleus accumbens amphetamine is impaired by antagonists of ERK or p38 MAP kinases in rats

The nucleus accumbens (NAc) plays a role in conditioned place preference (CPP). The authors tested the hypothesis that inhibition of mitogen-activated protein kinases (MAPKs) would inhibit NAc-amphetamine-produced CPP. Results confirmed that NAc amphetamine increased levels of the MAPK extracellular signal-regulated kinase (ERK). In CPP studies, NAc injections (0.5 microl per side) of the ERK inhibitor PD98059 (1.0-2.5 microg) or the p38 kinase inhibitor SB203580 (15-500 ng) dose dependently impaired CPP. The c-Jun-N-terminal kinase (JNK) inhibitor SP600125 (1.0-2.5 microg) failed to block the CPP effect. The drugs did not block amphetamine-induced motor activity. Results suggest that ERK and p38, but not JNK, MAPKs may be necessary for the establishment of NAc amphetamine-produced CPP and may also mediate other forms of reward-related learning dependent on NAc.     

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.     

Low concentrations of nitric oxide (NO) induced cell death in PC12 cells through activation of p38 mitogen-activated protein kinase (p38 MAPK) but not via extracellular signal-regulated kinases (ERK1/2) or c-Jun N-terminal protein kinase (JNK)

Nitric oxide (NO), a highly reactive gaseous molecule, has been previously reported to induce apoptosis-like cell death even at a low concentration in PC12 cells. In this study, we examined NO-induced activation of members of the mitogen-activated protein kinase (MAPK) family, i.e., p38 MAPK, extracellular signal-regulated kinases (ERK1/2), and c-Jun N-terminal protein kinase (JNK). Following the exposure of PC12 cells to an NO donor, (+)-(E)-4-ethyl-2-[hydroxyimino]-5-nitro-3-hexenamide (NOR3; 100 muM), the phosphorylation level of p38 MAPK increased time dependently from 2 to 6 h, but that of both ERK1/2 and JNK did not. Treatment with a p38 MAPK inhibitor SB203580 partially blocked the NOR3-induced cell death. Neither PD98059, U0126 (inhibitors of ERK1/2) nor SP600125 (a specific inhibitor of JNK) treatments had any significant effect on the NOR3-induced cell death. These findings suggest that the activation of a p38 MAPK pathway, but not that of ERK1/2 or JNK, plays an essential role in the apoptosis-like cell death induced by low concentrations of NO.     

Specific inhibitors of mitogen-activated protein kinase and PI3-K pathways impair immune responses by hemocytes of trematode intermediate host snails

To characterize molecular mechanisms regulating snail cellular immune responses, the contributions of mitogen-activated protein kinases (MAPKs) and phosphatidylinositol 3-kinase (PI3-K) were examined in hemocytes of the trematode intermediate host snails Biomphalaria glabrata and Lymnaea stagnalis. Simultaneous measurement of phagocytosis/encapsulation and H2O2 production by hemocytes in the presence or absence of specific signal transduction inhibitors was used to assess the role of extracellular-signal regulated kinases 1 and 2 (ERK1/2), p38, JNK and PI3-K. Hemocyte spreading was significantly reduced in a dose-dependent manner by the ERK inhibitor, PD098059, and by wortmannin, a potent PI3-K inhibitor. The JNK inhibitor, SP600125, and the p38 kinase inhibitor, SB203580, had no effect on hemocyte spreading. Sheep red blood cell phagocytosis was significantly impaired by PD098059, SP600125, and SB203580. Hydrogen peroxide production during phagocytosis was severely inhibited by PD098059. Additionally, PD098059, but not the other inhibitors, significantly impaired the cellular encapsulation of trematode larvae and H2O2 production during encapsulation. These results suggest that MAPK and PI3-K signal transduction pathways play a pivotal role in the immune responses of snail hemocytes. PI3-K and ERK appear to strongly regulate cell motility. ERK, JNK and p38 contribute to phagocytosis-mediated signal transduction. ERK also play a major role in oxidative burst activation and the encapsulation of trematode larvae by snail hemocytes.     

Stress-activated protein kinases mediate cell migration in human airway epithelial cells

Airway epithelial cell (AEC) repair immediately after injury requires coordinated cell spreading and migration at the site of injury. Stress-activated protein kinases such as p38 MAPK and c-Jun N-terminal Protein Kinase (JNK) modulate several responses to cell stress and injury, but their role in AEC migration is not clear. We examined migration in confluent 16HBE14o(-) human AEC lines and in primary AEC grown on collagen-IV. Wounds were created by mechanical abrasion and followed to closure using digital microscopy. Inhibitors of either p38 extracellular signal-regulated kinase (ERK)1/2 (PD98059), mitogen-activated protein kinase (MAPK) (SB203580), or JNK (SP600125) could block cell migration substantially. Inhibiting JNK but not p38 MAPK or ERK1/2 blocked extension of cells into the wound region from the original line of injury. Initial migration was associated with phosphorylation of ERK, p38 MAPK, and JNK within 5-15 min. The downstream effector of p38, heat shock protein 27, also was phosphorylated rapidly after injury; phosphorylation could be blocked by prior treatment with SB203580 but not SP600125. The downstream effector of JNK, c-Jun, likewise was phosphorylated rapidly after injury and could be blocked by inhibiting JNK. Our data demonstrate that p38 MAPK, JNK, and ERK1/2 participate in the early stages of AEC migration.