Effect of hydrogen peroxide on interleukin-8 synthesis and death of Caco-2 cells

Intestinal epithelial cells can secrete interleukin-8 (IL-8), among other substances in response to different stimuli, which plays an important role in mucosal immune response. Above a certain concentration range, hydrogen peroxide causes cell death by necrosis or apoptosis. We investigated the time- and dose-dependent induction of IL-8 by hydrogen peroxide in the human colon adenocarcinoma cell line Caco-2. In addition, the changes of transepithelial electrical resistance and cell death induction in response to hydrogen peroxide were studied. Nonfilter-grown and filter-grown Caco-2 cells were employed in our experiments. Interleukin-8 synthesis was measured by ELISA. Necrosis was determined by DAPI staining of cells, apoptosis by measuring caspase-3 enzyme activity or annexin V staining. In nonfilter-grown Caco-2 cells, 1 mM of hydrogen peroxide induced the highest level of IL-8 production 24 hr after treatment. In filter-grown Caco-2 cells, IL-8 was produced only on the apical side in response to 1 mM of hydrogen peroxide. This level was 10-fold lower than that measured in nonfilter-grown Caco-2 cells 24 hr after the treatment. In filter-grown Caco-2 cells 10 mM hydrogen peroxide induced the highest IL-8 level on the apical as well as basolateral side. Transepithelial electrical resistance decreased markedly upon application of 40 mM hydrogen peroxide. Late effect of hydrogen peroxide was observed in nonfilter-grown Caco-2 cells, as 1 mM hydrogen peroxide caused necrosis after 24 hr while early-necrosis induction occurred in filter-grown cells exposed to 40 mM of hydrogen peroxide after 1 hr. Filter-grown Caco-2 cells were less sensitive to hydrogen peroxide than the nonfilter-grown ones.     

肾病患者血清IL-8,FN和尿IL-8水平检测的临床意义

目的 :了解肾病患者血清IL - 8、FN和尿IL - 8水平、变化及意义。方法 :采用ELISA夹心法在疾病活动期和激素冲击治疗后 8周测定 5 1例肾病患者血清IL - 8、FN和晨尿IL - 8水平 ,并以 36例随机健康者作比较。结果 :肾病患者血清及尿IL - 8含量显著高于正常人组 (P <0 0 1)但与Scr无显著相关性 (r =0 .12 5 ,P >0 .0 5和r =0 .0 75 ,P >0 .0 5 )而血清FN水平则低于正常人组 (P <0 0 5 )。激素治疗 8周后 ,血、尿IL - 8水平均降低 (P <0 0 5 ) ,血清FN水平有所升高 ,但与治疗前比较无显著差异 (P >0 0 5 )。结论 :IL - 8、FN与肾病的发病机制有关 ,测定血清IL - 8、FN和尿IL - 8有助于判断肾病患者的炎症活动状况 ,有一定的临床价值。     

Peyer''s结淋巴细胞对上皮屏障功能的影响

目的 :体外建立稳定的上皮细胞与Peyer’s结淋巴细胞 (PPL)共培养体系 ,进一步研究该体系中的上皮细胞生理学特性。方法 :采用短路电流检测单层上皮细胞跨上皮电阻 (TER)的变化、半定量RT PCR方法检测上皮细胞间的紧密连接相关蛋白ZO 1和ZO 2mRNA的表达。结果 :①Caco 2细胞单层与PPL共培养的第 2天 ,无论是混合共培养还是上下共培养组的TER均与对照有统计学差异 (P <0 0 5 ) ;②同时上下共培养或混合共培养组在第 8天TER仍保持较高水平 ,与对照有统计学差异 (P <0 0 5 ) ;③在上下共培养和混合共培养组中 ,半定量RT PCR检测ZO 1mRNA的表达也均明显高于对照。结论 :Peyer’s结淋巴细胞 (PPL)可以较好地维持上皮屏障功能。     

Interleukin-8 differentially modulates interleukin-4- and interleukin-2-induced human B cell growth

The effect of interleukin-8 (IL)-8 on human B cell growth, as determined by thymidine uptake and viable cell numbers was studied. IL-8 inhibited IL-4-induced growth of B cells costimulated with anti-μ antibodies (Ab) or Staphylococcus aureus Cowan strain I (SAC) in a dose-dependent fashion. In contrast, IL-8 did not inhibit IL-2-induced growth of B cells. The IL-8-mediated inhibition was specific, since it was blocked by anti-IL-8 mAb but not by control IgG1. Moreover, anti-tumor necrosis factor-α (anti-TNF-α) Ab blocked IL-8-mediated inhibition. On the other hand, TNF-α, but not other cytokines including IL-1β, IL-3, IL-5, IL-6, interferon-α (IFN-α) or IFN-γ, inhibited IL-4-mediated growth, and inhibition by TNF-α was blocked by anti-TNF-α Ab but not by control IgG. IL-4 had no effect on TNF-α binding by B cells while it decreased TNF-α production by B cells. IL-8 had no effect in binding of IL-4, IL-2 or TNF-α by B cells, however, it enhanced TNF-α production by B cells. These results indicate that IL-8 inhibited IL-4-induced human B cell growth by enhancement of endogenous TNF-α production.     

MyD88缺去突变基因转染降低病原菌感染的人呼吸道上皮细胞IL-8的分泌

白细胞介素-8（1L-8）是呼吸道炎症反应的重要介质。本实验通过构建突变MyD88真核表达质粒（MyD88 DN），转染人呼吸道上皮细胞株A549及SPC-A-1，探讨其对病原菌感染上皮细胞IL-8表达的影响。结果显示：MyD88 DN转染可降低结核杆菌、绿脓杆菌培养上清诱导的IL-8释放；对肺炎克雷伯杆菌和绿脓杆菌活菌侵袭细胞所刺激的IL-8分泌也有明显的阻断作用。提示突变MyD88能够阻断细菌感染引起的呼吸道上皮细胞IL-8表达，可能成为呼吸道严重炎症反应基因治疗的新靶基因。     

ERK1/2信号转导途径在低切应力上调人脐静脉内皮细胞IL-8基因表达中的作用

血管内皮细胞位于血流和血管壁之间,除受化学因素的调节外还受力学因素的影响。切应力可通过刺激相应的力学感受系统来调节内皮细胞某些基因的表达,其中包括诱导内皮细胞表达IL- 8。为了阐明MAPK信号途径中的ERK1/ 2信号通路是否参与调控低切应力上调人脐静脉内皮细胞IL- 8基因表达,采用Western blot分析了低切应力(4.2 0 dyne/ cm2 )处理不同时间内皮细胞ERK1/ 2的磷酸化水平及TPK抑制剂Genistein,MEK抑制剂PD980 5 9对其磷酸化的影响;采用定量RT- PCR检测内皮细胞经低切应力刺激或给予阻断剂后再行切应力刺激等处理后IL- 8基因的表达。结果显示:(1)低切应力处理可引起内皮细胞ERK1/ 2蛋白磷酸化水平上调,其磷酸化水平与切应力作用时间有关,具有快速、双向性的特点(在刺激10 min时达到高峰,2 h左右降至未刺激水平) ,阻断剂Genistein和PD980 5 9处理后,ERK1/ 2磷酸化水平与低切应力刺激10 min比较明显降低;(2 )阻断剂Genistein,PD980 5 9可显著抑制低切应力所致的内皮细胞IL- 8m RNA上调。结果表明低切应力可通过ERK1/ 2信号途径上调人脐静脉内皮细胞IL- 8基因的表达。     

Influence of lactic acid bacteria and their spent culture supernatant on hydrogen peroxide-induced interleukin-8 synthesis and necrosis of Caco-2 cells

Intestinal epithelial cells are confronted with many noxious stimuli which play an important role in the mucosal immune response. In the present study, Caco-2 cells treated with hydrogen peroxide were used as a model system for studying inflammatory responses and induction of cell death. Live lactobacilli and their concentrated spent culture supernatant (SCS) were applied for studying possible short- and long-term protective effects against hydrogen peroxide-mediated oxidative stress in Caco-2 cells. The secretion of pro-inflammatory cytokine interleukin-8 (IL-8) was investigated in non-filter grown Caco-2 cells, while transepithelial electrical resistance and cell death was studied in filter grown Caco-2 cells. Pre-incubation of Caco-2 cells with Lactobacillus plantarum 2142 did not decrease IL-8 levels induced by 1 mM hydrogen peroxide, nor did lactobacilli suppress IL-8 levels induced by hydrogen peroxide when Caco-2 cells were treated simultaneously with 1 mM hydrogen peroxide and L. plantarum 2142. Thus, lactobacilli did not exert a long-term protective effect against hydrogen peroxide in non-filter grown Caco-2 cells. However, the concentrated SCS of lactobacilli was able to reduce IL-8 levels by more than 6-fold, as determined 24 h after treatment. A short-term effect of lactobacilli was observed in filter grown Caco-2 cells, as they inhibited cell death induced by hydrogen peroxide in the concentration range 10-40 mM. Pre-incubation of epithelial cells with L. plantarum 2142 or simultaneous exposure to hydrogen peroxide and lactobacilli protected Caco-2 cells against cell death. In spite of the presence of lactobacilli, the permeability of membrane increased (transepithelial electrical resistance decreased), and exhibited a similar characteristic pattern as under treatment with hydrogen peroxide alone.     

Interleukin-8 and its receptor CXCR2 in atherosclerosis

The participation of inflammatory cells in atherosc lerosis is a well-known process that involves numerous molecules including chemotactic cytokines (chemokines) for their entry into the vessel wall. Although the C-C chemokine monocyte chemoattractant protein-1 and its receptor, CCR2, have been implicated in atherosclerosis, the role of the classic C-X-C chemokine, interleukin-8 (KC/growth-related oncogene α in mice) and its receptor XCCR2 has not been studied in the pathogenesis of atherosclerosis. Our research has shown that CXC R2 is strongly expressed on macrophages (Mф) in atherosclerotic lesion. This CXCR2 expression is proatherogenic in that CXCR2 deficiency significantly reduces the progression of advanced atherosclerosis in mice. Although the mechanism still needs to be worked out, it appears that CXCR2 expression on lesion Mф is essential for these cells to be retained in the lesion.     

Effect of Cholesterol Depletion on Interleukin-8 Production in Human Respiratory Epithelial Cells

Purpose

The lipid entities of cell membranes are components of the immune system and important mediators of inflammation. Despite increasing interest in the function of epithelial cells in inflammation, the role of cholesterol in this process has not been described. Here, we investigated the effect of cholesterol depletion on the inflammatory process in airway epithelial cells via the expression of interleukin (IL)-8 as a marker of inflammation.

Methods

A 549 cells were treated with 0.5% methyl-β-cyclodextrin as a selective cholesterol extractor. The IL-8 level was assessed by enzyme-linked immunosorbent assay and reassessed after cholesterol repletion. Mitogen-activated protein kinase (MAPK) inhibitors were used to determine the upstream signaling pathway for IL-8 production in cholesterol-depleted cells.

Results

We found a relationship between the amount of cholesterol in A 549 cells and inflammation of the airway. IL-8 production was increased in cholesterol-depleted A 549 cells and restored by cholesterol repletion. IL-8 production was decreased by pretreatment with the extracellular signal-regulated kinase (ERK) inhibitor U0126 but not with JNK inhibitor II or the p38 MAPK inhibitor SB202190.

Conclusions

Our findings suggest that inflammatory responses are increased in cholesterol-depleted epithelial cells via the MAPK signaling system, predominantly by the ERK pathway. We conclude that the lipid components of airwayepithelial cells may play a role in the inflammatory process.     

白细胞介素2快速诱导人LAK细胞的实验研究

本文采用~(125)IUdR释放法测定了大剂量白细胞介素2(IL-2)体外短期诱导人脐血,正常人、良性瘤及恶性瘤病人外周血淋巴细胞的抗肿瘤活性,发现四种来源的淋巴细胞在大剂量IL-3作用15分钟时均可诱导出一定水平的LAK活性,最适IL-2用量为6×10~3u/1.2×10~7细胞/ml,最适体外培养时间为3天。     

抗精神病药物对儿童少年精神分裂症患者血清白介素-2的影响

目的 探讨抗精神病药物对少年儿童精神分裂症患者血清白介素-2(IL-2)的影响及IL-2与精神病理的关系。方法 选择少年儿童精神分裂症患者41例,分别在治疗前和治疗后第4、8周末用酶免疫吸附法检测血清IL-2水平,以健康少年儿童作对照．用阴性与阳性症状量表(PANSS)评定精神症状及其变化。结果 少年儿童精神分裂症患者治疗前血清IL-2水平显著高于对照组．治疗后第4、8周末血清IL-2水平显著低于治疗前．治疗后第4周末血清IL-2水平与阳性症状呈正相关。结论 少年儿童精神分裂症患者存在细胞免疫异常,抗精神病药物对少年儿童精神分裂症患者有免疫抑制作用,血清IL-2与精神病理有一定的关系。     

同型半胱氨酸对人THP-1巨噬细胞IL-8 mRNA及其蛋白表达的影响

目的:探讨同型半胱氨酸(Hcy)对人THP-1巨噬细胞IL-8 mRNA的表达和IL-8分泌的影响。方法:在由0.1 μmol/L佛波脂(PMA)诱导分化的人THP-1巨噬细胞中加入不同浓度的Hcy,并孵育不同时间。用酶联免疫吸附法(ELISA)检测培养上清液中IL-8蛋白的含量,用半定量RT-PCR法检测IL-8 mRNA表达。结果:经PMA诱导后,THP-1细胞贴壁生长,分化成巨噬细胞。在一定浓度范围之内,Hcy呈剂量依赖性刺激THP-1巨噬细胞分泌IL-8蛋白,0.05 mmol/L Hcy即可促进其分泌增加为对照组的1.28倍(P<0.01);0.20 mmol/L Hcy使IL-8的产量增加到对照组的1.55倍(P<0.01)。0.10 mmol／L Hcy干预后,IL-8蛋白在3 h即高于对照组,到48 h仍明显高于对照组。半定量RT-PCR结果也显示Hcy能刺激IL-8 mRNA表达,呈剂量和时间依赖关系。结论:Hcy能促进人THP-1巨噬细胞IL-8 mRNA表达和分泌IL-8蛋白。这可能为其诱导动脉粥样硬化的重要机制之一。     

糖尿病肾病患者与相关细胞因子水平的变化

目的:探讨了糖尿病肾病患者的血清白介素-2、白介素-6、白介素-8和肿瘤坏死因子水平的变化在肾病发生、发展过程中的作用。方法:应用放射免疫分析对38例糖尿病肾病患者和36例正常人进行了血清IL-2、IL-6、IL-8和TNF水平的检测。结果:糖尿病肾病患者血清中IL-6、IL-8和TNF水平非常显著地高于正常人组(P<0.01),而IL-2水平则显著地低于正常人组(P<0.01)。结论:血清IL-2、IL-6、IL-8和TNF水平的变化在糖尿病肾病的发生和发展中相互作用,观察其浓度的变化对探讨其发病机理、预防和指导用药均有十分重要的临床价值。     

Hydrogen Peroxide Is Crucial for NLRP3 Inflammasome-Mediated IL-1β Production and Cell Death in Pneumococcal Infections of Bronchial Epithelial Cells

Epithelial cells play a crucial role in detection of the pathogens as well as in initiation of the host immune response. Streptococcus pneumoniae (pneumococcus) is a typical colonizer of the human nasopharynx, which can disseminate to the lower respiratory tract and subsequently cause severe invasive diseases such as pneumonia, sepsis, and meningitis. Hydrogen peroxide (H₂O₂) is produced by pneumococci as a product of the pyruvate oxidase SpxB. However, its role as a virulence determinant in pneumococcal infections of the lower respiratory tract is not well understood. In this study, we investigated the role of pneumococcal-derived H₂O₂ in initiating epithelial cell death by analyzing the interplay between 2 key cell death pathways, namely, apoptosis and pyroptosis. We demonstrate that H₂O₂ primes as well as activates the NLRP3 inflammasome and thereby mediates IL-1β production and release. Furthermore, we show that pneumococcal H₂O₂ causes cell death via the activation of both apoptotic as well as pyroptotic pathways which are mediated by the activation of caspase-3/7 and caspase-1, respectively. However, H₂O₂-mediated IL-1β release itself occurs mainly via apoptosis.     

宫颈癌细胞产生的免疫抑制因子对IL－2作用的影响

人宫颈癌细胞产生的免疫抑制因子（ＴＤＳＦ）作用于人外周血单个核细胞（ＰＢＭＣ）６ｈ，即可抑制白细胞介素２（ＩＬ－２）产生，与对照组相比，Ｐ＜０．０１。当ＴＤＳＦ存在时，经ＰＨＡ－Ｐ驯化的ＰＢＭＣ效应细胞对外源性ＩＬ－２反应显著减弱，表明ＴＤＳＦ能抑制ＩＬ－２的作用。ＰＨＡ－Ｐ刺激ＰＢＭＣ增殖，但ＴＤＳＦ使其增殖抑制。表明ＴＤＳＦ能抑制ＩＬ－２产生及其作用；抗癌药对ＴＤＳＦ的分泌有部分阻抑作用。     

宫颈癌细胞产生的免疫抑制因子对IL－2作用的影响

人宫颈癌细胞产生的免疫抑制因子（ＴＤＳＦ）作用于人外周血单个核细胞（ＰＢＭＣ）６ｈ，即可抑制白细胞介素２（ＩＬ－２）产生，与对照组相比，Ｐ＜０．０１。当ＴＤＳＦ存在时，经ＰＨＡ－Ｐ驯化的ＰＢＭＣ效应细胞对外源性ＩＬ－２反应显著减弱，表明ＴＤＳＦ能抑制ＩＬ－２的作用。ＰＨＡ－Ｐ刺激ＰＢＭＣ增殖，但ＴＤＳＦ使其增殖抑制。表明ＴＤＳＦ能抑制ＩＬ－２产生及其作用；抗癌药对ＴＤＳＦ的分泌有部分阻抑作用。     

In vitro effects of velvet antler water extracts from Formosan Sambar deer and red deer on barrier integrity in Caco-2 cell

Background: The mucus integrity and abnormal inflammatory response are the crucial biomarker of inflammatory bowel disease (IBD). Velvet antler (VA) has been used as traditional Chinese medicines for many years. Anti-inflammatory property was demonstrated via suppression of cyclooxygenase-2 and cytokines protein expression. And it has further proved to promote wound healing in streptozotocin-induced diabetic rats model. The aforementioned functionalities of VA extracts may be associated with the treatment of IBD. Thus, the aim of present study was to evaluate the effect of velvet antler water extracts form Formosan Sambar deer (Rusa unicolor swinhoei, SVAE) and red deer (Cervus elaphus, RVAE) on the barrier function and to investigate the possible mechanism using in vitro model.Methods: Human colonic epithelial cell models (Caco-2) were co-cultured with various concentrations of both SVAE and RVAE (250-500 µg mL^-1) in dextran sulfate sodium (DSS)-induced colitis model. Trans-epithelial electrical resistance (TEER) value and the macromolecule permeability of Fluorescein isothiocyanate (FITC)-labeled dextran were measured to evaluate the integrity of monolayer of Caco-2. Western blotting was performed for analysis of protein expressions of occludin, Zonula occludens-1 (ZO-1), claudin-1, claudin-2 and myosin light chain kinase (MLCK). The cytotoxicity was conducted by MTT assay.Results: Results indicated that both SVAE and RVAE could enhance integrity of monolayer in dextran sulfate sodium (DSS)-induced colonic epithelial cell model (Caco-2) through reducing the decline of trans-epithelial electrical resistance (TEER) and macromolecule permeability at the concentration of 250 μg mL^-1. RVAE significantly increased the expression of tight junction proteins (occludin and ZO-1) while SVAE significantly reduced the activity of MLCK (P < 0.05.). Elevated C-C chemokine ligand 20 (CCL20) production suggested that both SVAE and RVAE could enhance the repair of epithelial cell. Besides, MTT assay revealed that both extracts showed no cytotoxicity.Conclusion: Thus, SVAE and RVAE supplementation may attenuate barrier damage by enhancing the occludin and ZO-1 protein expression, decreasing MLCK expression, promoting the CCL20 production. In the future, animal study is needed for further confirmation.     

Separation Methods of T Cells,Natural Killer,and Dendritic Cells from Peripheral Blood of Cancer Patients using Interleukin-2 and Functional Analysis of Natural Killer Cells after Separation

We aimed to induce three different immune cell subsets from a single blood sample from cancer patients to target different biological characters of cancer cells. In the presence of 6000 IU/ml IL-2, natural killer (NK) cells adhere to plastic. By using this ability, we could separate dendritic cells, T cells, and NK cells from peripheral blood mononuclear cells. The cultured NK cells demonstrated higher nonspecific cytotoxicity against tumor cell lines than did the T cells. Furthermore, adherent NK cells demonstrated higher cytotoxicity than nonadherent NK cells, although there was no difference between adherent and nonadherent NK cells in natural cytotoxicity receptors (NKp30, NKp44, NKp46) and NKG2D expression. With these results, we confirmed that we could induce dendritic cell, T cell, and higher cytotoxic NK cells from a single blood draw, and this methodology facilitates to the use of these cells for clinical grade conditions.     

Effects of C5a and FMLP on Interleukin-8 Production and Proliferation of Human Umbilical Vein Endothelial Cells

Interleukin-8 (IL-8), C5a and N-formyl-methionyl-leucyl-phenylalanine (fMLP) are chemotactic peptides with predominant effects on leukocytes during inflammation. With emphasis on C5a we studied the regulation of the production of IL-8 by human umbilical vein endothelial cells (HUVEC) in vitro. Primary HUVEC cultures were incubated with IL-1, TNF, C5a and fMLP for 24 h and 48 h prior to measurement of IL-8 in supernatants of the cells by an enzyme immunoassay. Whereas IL-1 and TNF significantly increased the levels of IL-8, C5a decreased the IL-8 production after 48 h. In addition, the ability of IL-1, TNF, C5a, fMLP and IL-8 to induce cell proliferation was compared by means of a ³H-thymidine incorporation assay. In contrast with IL-1 and TNF, both C5a and fMLP increased cell proliferation of HUVEC. This increase occurred with increasing concentrations of C5a contrary to IL-8, which showed increased cell proliferation at low, but not high IL-8 concentrations.