Lactobacillus acidophilus Induces Cytokine and Chemokine Production via NF-��B and p38 Mitogen-Activated Protein Kinase Signaling Pathways in Intestinal Epithelial Cells

Intestinal epithelial cells can respond to certain bacteria by producing an array of cytokines and chemokines which are associated with host immune responses. Lactobacillus acidophilus NCFM is a characterized probiotic, originally isolated from human feces. This study aimed to test the ability of L. acidophilus NCFM to stimulate cytokine and chemokine production in intestinal epithelial cells and to elucidate the mechanisms involved in their upregulation. In experiments using intestinal epithelial cell lines and mouse models, we observed that L. acidophilus NCFM could rapidly but transiently upregulate a number of effector genes encoding cytokines and chemokines such as interleukin 1α (IL-1α), IL-1β, CCL2, and CCL20 and that cytokines showed lower expression levels with L. acidophilus NCFM treatment than chemokines. Moreover, L. acidophilus NCFM could activate a pathogen-associated molecular pattern receptor, Toll-like receptor 2 (TLR2), in intestinal epithelial cell lines. The phosphorylation of NF-κB p65 and p38 mitogen-activated protein kinase (MAPK) in intestinal epithelial cell lines was also enhanced by L. acidophilus NCFM. Furthermore, inhibitors of NF-κB (pyrrolidine dithiocarbamate [PDTC]) and p38 MAPK (SB203580) significantly reduced cytokine and chemokine production in the intestinal epithelial cell lines stimulated by L. acidophilus NCFM, suggesting that both NF-κB and p38 MAPK signaling pathways were important for the production of cytokines and chemokines induced by L. acidophilus NCFM.     

Differential regulation of mast cell cytokines by both dexamethasone and the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580

Activated mast cells generate multiple cytokines but it is not known if these can be differentially regulated by pharmacological agents. We report here that the glucocorticoid dexamethasone (DEX) preferentially inhibited Ag-induced expression of IL-4 and IL-6 mRNA relative to TNF-alpha mRNA in RBL-2H3 cells. Likewise, the drug more readily inhibited release of IL-4 than TNF-alpha protein. SB203580, an inhibitor of p38 mitogen-activated protein kinase (MAPK), enhanced Ag-induced TNF-alpha mRNA expression without affecting IL-4 or IL-6 mRNA. At the protein level, SB203580 exerted little effect on TNF-alpha release but inhibited IL-4 release; notably, the ratio of TNF-alpha : IL-4 increased markedly with the concentration of SB203580, confirming the differential regulation of these cytokines. PD98059, an inhibitor of MAPK kinase (MEK), a component of the p44/42 MAPK pathway, partially inhibited Ag-induced expression of mRNA for all three cytokines while cyclosporin A inhibited Ag-induced IL-4 and IL-6 mRNA more readily than TNF-alpha mRNA. Ag activation of the cells led to phosphorylation of p38 and p44/42 MAPK but this was not influenced by DEX. In conclusion, mast cell cytokines can be differentially regulated pre- and post-translationally by DEX and SB203580 but there does not appear to be a direct mechanistic link between the actions of these two drugs.     

屋尘螨提取物激活气道上皮细胞EphA2-STAT3/p38 MAPK信号通路介导气道炎症

目的探讨受体酪氨酸激酶肝配蛋白A型受体2(EphA2)对屋尘螨提取物(HDM)诱导气道上皮细胞表达炎症细胞因子的作用及其机制。方法用EphA2小干扰RNA(siRNA)转染气道上皮细胞株16HBE细胞建立EphA2敲减的细胞模型,HDM刺激16HBE细胞后,采用实时定量PCR检测EphA2、白细胞介素6(IL-6)和IL-8 mRNA水平,细胞因子微球检测技术(CBA)检测IL-6、 IL-8、 IL-17A、 IL-17F和肿瘤坏死因子α(TNF-α)蛋白水平;Western blot法检测EphA2、磷酸化的EphA2(p-EphA2)、信号转导子与转录激活子3(STAT3)、磷酸化的STAT3(p-STAT3)、 p38丝裂原激活蛋白激酶(p38 MAPK)、磷酸化的p38 MAPK(p-p38 MAPK)、核因子κB p65(NF-κB p65)及磷酸化的NF-κB p65(p-NF-κB p65)蛋白水平。STAT3抑制剂Stattic联合HDM或p38 MAPK抑制剂SB203580联合HDM刺激16HBE细胞,实时定量PCR检测IL-6和IL-8 mRNA水平、 CBA检测IL-6和IL-8蛋白水平。结果敲低EphA2显著抑制HDM诱导16HBE细胞表达IL-6和IL-8,降低STAT3及p38 MAPK的总蛋白及磷酸化水平,但对NF-κB p65总蛋白及磷酸化水平均无明显影响。Stattic抑制STAT3表达及活化后,显著抑制HDM诱导16HBE细胞中IL-6和IL-8 mRNA和蛋白表达;而SB203580抑制p38 MAPK信号通路后,抑制HDM诱导16HBE细胞中IL-6和IL-8 mRNA表达水平,而对其蛋白水平无影响。结论 HDM通过激活EphA2-STAT3/p38 MAPK通路诱导16HBE细胞表达IL-6和IL-8参与气道炎症。     

c-Jun NH₂-terminal kinase contributes to dexmedetomidine-induced contraction in isolated rat aortic smooth muscle

Purpose

Dexmedetomidine, a full agonist of α_2B-adrenoceptors, is used for analgesia and sedation in the intensive care units. Dexmedetomidine produces an initial transient hypertension due to the activation of post-junctional α_2B-adrenoceptors on vascular smooth muscle cells (SMCs). The aims of this in vitro study were to identify mitogen-activated protein kinase (MAPK) isoforms that are primarily involved in full, α_2B-adrenoceptor agonist, dexmedetomidine-induced contraction of isolated rat aortic SMCs.

Materials and Methods

Rat thoracic aortic rings without endothelium were isolated and suspended for isometric tension recording. Cumulative dexmedetomidine (10^-9 to 10^-6 M) dose-response curves were generated in the presence or absence of extracellular signal-regulated kinase (ERK) inhibitor PD 98059, p38 MAPK inhibitor SB 203580, c-Jun NH₂-terminal kinase (JNK) inhibitor SP 600125, L-type calcium channel blocker (verapamil and nifedipine), and α₂-adrenoceptor inhibitor atipamezole. Dexmedetomidine-induced phosphorylation of ERK, JNK, and p38 MAPK in rat aortic SMCs was detected using Western blotting.

Results

SP 600125 (10^-6 to 10^-5 M) attenuated dexmedetomidine-evoked contraction in a concentration-dependent manner, whereas PD 98059 had no effect on dexmedetomidine-induced contraction. SB 203580 (10^-5 M) attenuated dexmedetomidine-induced contraction. Dexmedetomidine-evoked contractions were both abolished by atipamezole and attenuated by verapamil and nifedipine. Dexmedetomidine induced phosphorylation of JNK and p38 MAPK in rat aortic SMCs, but did not induce phosphorylation of ERK.

Conclusion

Dexmedetomidine-induced contraction involves a JNK- and p38 MAPK-mediated pathway downstream of α₂-adrenoceptor stimulation in rat aortic SMCs. In addition, dexmedetomidine-induced contractions are primarily dependent on calcium influx via L-type calcium channels.     

Interleukin-3, -5, and Granulocyte Macrophage Colony-Stimulating Factor Induce Adhesion and Chemotaxis of Human Eosinophils via p38 Mitogen-Activated Protein Kinase and Nuclear Factor κB

Hematopoietic cytokines such as interleukin (IL)-3, IL-5, and granulocyte macrophage colony-stimulating factor (GM-CSF) play a fundamental role in eosinophil functions in allergic asthma. The intracellular signal transduction mechanisms of these cytokines regulating the activation of eosinophils have been potential therapeutic targets. We investigated the roles of p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) in IL-3, IL-5, and GM-CSF-induced adhesion, morphological changes, and subsequence transmigration of human eosinophils. IL-3, IL-5, and GM-CSF could augment the phosphorylation of p38 MAPK and nucleus translocation of NF-κB in eosinophils. cDNA expression arrays demonstrated that the gene expression levels of several adhesion molecules including intercellular adhesion molecule-1 (ICAM-1), α6, β2 integrin (CD18), and CD44 were upregulated by these cytokines. Results from functional assays showed that adhesion of eosinophils onto airway epithelial cells was enhanced after IL-3 and IL-5 but not GM-CSF stimulation. These cytokines could markedly induce shape change and augment the transmigration of eosinophils. Moreover, administration of either p38 MAPK inhibitor, SB 203580, or proteasome inhibitor, N-cbz-Leu-Leu-leucinal (MG-132), could inhibit the cytokine-induced adhesion, shape change, and transmigration of eosinophils. Together, our findings suggest that IL-3, IL-5, and GM-CSF regulated the adhesion and chemotaxis of human eosinophils through shared signaling pathways involving both p38 MAPK and NF-κB. Our results therefore shed light on the further development of more effective agents for allergic and inflammatory diseases.     

mmLDL通过p38 MAPK通路上调小鼠肠系膜动脉ET受体

目的:探讨弱氧化修饰低密度脂蛋白(mm LDL)是否通过激活p38 MAPK炎症通路上调小鼠肠系膜动脉内皮素(ET)A型(ETA)和B型(ETB)受体。方法:将昆明小鼠分为正常对照组(尾静脉注射生理盐水)、mm LDL组(尾静脉注射mm LDL)、LDL组(尾静脉注射LDL)、mm LDL+SB 203580组(尾静脉注射mm LDL及腹腔注射p38 MAPK抑制剂SB 203580)和mm LDL+DMSO组(尾静脉注射mm LDL及腹腔注射DMSO)。微血管张力描记仪记录ETB受体激动剂角蝰毒素6c和ET-1引起肠系膜动脉收缩的量效曲线;RT-q PCR检测ETB受体、ETA受体和白细胞介素(IL-6)的m RNA表达;ELISA检测血清IL-6的水平;Western blot检测ETB受体、ETA受体、IL-6、p38 MAPK、p-p38MAPK、NF-κB和p-NF-κB的蛋白水平。结果:mm LDL引起ETB受体和ETA受体介导的血管收缩反应显著增强(P<0.01),ETB受体、ETA受体和IL-6的m RNA和蛋白表达显著增加(P<0.01),p-p38 MAPK和p-NF-κB蛋白水平显著升高(P<0.01),血清中IL-6水平显著升高(P<0.01);腹腔注射SB 203580抑制了mm LDL的作用。mm LDL引起的IL-6血清浓度升高分别与ETB受体和ETA受体介导的最大收缩率呈正相关。结论:mm LDL通过激活p38 MAPK通路及下游NF-κB转录因子,提高炎症因子IL-6血清水平,增加小鼠肠系膜动脉IL-6、ETA受体和ETB受体表达,增强ETA受体和ETB受体介导的血管收缩功能。     

ET-1介导损伤气道上皮诱导成纤维细胞活化的信号机制

目的： 探讨p38丝裂原活化蛋白激酶(MAPK)、磷脂酰肌醇3-激酶(PI3K/Akt)在内皮素(ET)-1介导损伤气道上皮诱导上皮下成纤维细胞活化过程中的作用及对白细胞介素(IL)-6的影响。方法：将正常或经多聚左旋精氨酸(PLA)刺激的人气道上皮细胞与原代气道成纤维细胞共培养并分别加入p38 MAPK、PI3K特异性抑制剂SB203580、LY294002或ET受体A阻断剂BQ123,应用免疫组化、免疫印迹技术或ELISA检测成纤维细胞α-平滑肌肌动蛋白（α-SMA）表达、p38 MAPK、Akt的活化及成纤维细胞上清IL-6水平;制备成纤维细胞胶原凝胶并与不同方法处理的上皮细胞共培养,测量各组凝胶面积变化以了解上皮细胞对成纤维细胞收缩反应的诱导及其上述处理因素的影响。结果：与损伤上皮细胞共培养的成纤维细胞上清中ET-1、IL-6水平［（13.69±1.36） ng/L、(56.7±10.7) ng/L］明显高于与正常上皮细胞共培养的成纤维细胞上清［（3.79±0.64） ng/L、（15.5±3.2）ng/L］,BQ123、SB203580或LY294002皆不同程度减弱损伤上皮细胞诱导的IL-6释放［分别为(27.2±3.1) ng/L、(31.5±3.6) ng/L、(41.3±3.2) ng/L］;成纤维细胞与损伤气道上皮细胞共培养后p38 MAPK、Akt先后激活,BQ123减弱磷酸化p38 MAPK、Akt水平,SB203580浓度依赖性减弱Akt磷酸化水平,而LY294002对磷酸化p38 MAPK水平影响很小。与损伤气道上皮细胞共培养后成纤维细胞α-SMA表达增加,并且胶原收缩百分比明显大于与正常气道上皮共培养的成纤维细胞［(61.2±2.7)% vs (15.4±7.3)%］;BQ123、SB203580及LY294002皆不同程度减弱成纤维细胞α-SMA表达与凝胶收缩且BQ123、SB203580抑制凝胶收缩作用较LY294002更明显。结论：ET-1通过激活p38 MAPK、PI3K/Akt信号通路并促进IL-6分泌在损伤气道上皮诱导成纤维细胞活化过程中发挥关键作用。     

p38/ATF-2通路参与C反应蛋白诱导的内皮细胞活化

目的:考察p38 MAPK/ATF-2通路在C反应蛋白(CRP)诱导的内皮细胞活化中的作用。方法:采用培养的人冠状动脉内皮细胞(HCAEC)第3~7代用于实验。CRP刺激诱导内皮细胞活化,给予p38抑制剂SB203580和SB202190干预。免疫印迹法检测p-e NOS、p-p38和p-ATF2的水平;ELISA法测定HCAEC分泌的黏附分子ICAM-1、VCAM-1和MCP-1的变化。结果:CRP呈浓度依赖性地抑制p-e NOS水平,CRP诱导HCAEC分泌ICAM-1、VCAM-1和MCP-1;CRP激活p38/ATF-2通路;SB203580和SB202190部分恢复p-e NOS水平和抑制CRP诱导的ICAM-1、VCAM-1和MCP-1分泌。结论:p38 MAPK/ATF-2通路参与CRP诱导的HCAEC活化。