Reactive Oxygen Species in the Immune System

Reactive oxygen species (ROS) are a group of highly reactive chemicals containing oxygen produced either exogenously or endogenously. ROS are related to a wide variety of human disorders, such as chronic inflammation, age-related diseases and cancers. Besides, ROS are also essential for various biological functions, including cell survival, cell growth, proliferation and differentiation, and immune response. At present there are a number of excellent publications including some reviews about functions of these molecules either in normal cell biology or in pathophysiology. In this work, we reviewed available information and recent advances about ROS in the main immune cell types and gave summary about functions of these highly reactive molecules both in innate immunity as conservative defense mechanisms and in essential immune cells involved in adaptive immunity, and particularly in immune suppression.     

Effects of antibiotics on biochemical parameters,leukocytes and Reactive Oxygen Species (ROS) in bitches after ovariectomy

It is well known that following surgical procedures, a variety of patho-physiological alterations occurs in the host, such as changes in haemodynamic, endocrine and immune functions, as well as increase in Reactive Oxygen Species (ROS). Antibiotic administration, a common practice used in surgery, affects immune functions and ROS generation. Our study was aimed to investigate the effect of five different antibiotic regimens: amoxicillin, benzylpenicillin/dihydrostreptomycin, sulfametazine/sulfamerazine/ sulfathiazole, enrofloxacin, lincomycin/spectinomycin, administered twice (2 hours before skin incision and 6 hours after the end of the surgical suture), on biochemical parameters, leukocytes and ROS concentrations, in bitches undergoing open laparotomic ovariectomy. All treated bitches recovered from surgery without developing either systemic dysfunctions, or infections at the surgical site. Mean healing time was 7?±?3 days. An increase in white blood cell count, in differential leukocyte count and in ROS concentrations occurred 24 hours after the end of surgery, followed by a gradual decrease to basal values within the fourth day after surgery. The biochemical parameters remained quite constant throughout the study. In conclusion, our results show that the above antibiotic regimens, administered only twice, are efficient in inducing an uneventful recovery after laparotomic ovariectomy and preventing the development of infections in the bitch.     

Expression of Intracellular Reactive Oxygen Species in Hematopoietic Stem Cells Correlates with Time to Neutrophil and Platelet Engraftment in Patients Undergoing Autologous Bone Marrow Transplantation

Reactive oxygen species (ROS) play important roles in hematopoiesis and regulate the self-renewal, migration, and myeloid differentiation of hematopoietic stem cells (HSCs). This study was conducted to determine whether ROS levels in donor HSCs correlate with neutrophil and platelet engraftment in patients after bone marrow transplantation.Cryopreserved HSC samples from 51 patients who underwent autologous transplantation were studied. Levels of intracellular ROS were assessed by flow cytometry using 2′,7′-dichlorodihydrofluorescein diacetate (H₂DCFDA) in the CD45⁺/CD34⁺ HSC population. Colony forming unit assays were performed on HSCs isolated from the ROS^high and ROS^low populations to assess the differentiation potential of these 2 cell subsets.Distinct populations of ROS^high and ROS^low cells were evident in all patient samples. The median percentage of ROS^high expressing HSCs in the study cohort was 75.8% (range, 2% to 95.2%). A significant correlation was identified between the percentage of ROS^high stem cells present in the hematopoietic progenitor cells collected by apheresis product infused and the time to neutrophil engraftment (P < .001, r = –.54), as well as time to plt20, plt50, and plt100 (P < 0.001; r?=?–.55, –.59, and –.56 respectively). The dose of CD34⁺/ROS^high/kg infused also inversely correlated with a shorter time to neutrophil engraftment; time to engraftment for patients receiving > or ≤3?×?10⁶ cells/kg was 11.5 days (range, 9 to 23) versus 14 days (range, 10 to 28), respectively (P?=?.02). The dose of ROS^high HSCs delivered did not correlate with platelet engraftment.Collectively, these data suggest that the dose of ROS^high stem cells delivered to patients may predict time to neutrophil engraftment after autologous transplantation.     

Phagocytosis following Translocation of the Neutrophil b-Cytochrome from the Specific Granule to the Plasma Membrane is Associated with an Increased Leakage of Reactive Oxygen Species

The effect of neutrophil b-cytochrome translocation on the respiratory burst activation generated during phagocytosis of yeast particles was investigated. Secretion of neutrophil specific granules was induced by the calcium ionophore ionomycin prior to phagocytosis. The secretory process is associated with a translocation from the specific granules to the plasma membrane of the respiratory burst b-cytochrome. Respiratory burst activity was measured as release of hydrogen peroxide in the absence of azide (extracellular leakage) and in the presence of azide (total production). The subcellular localization of the b-cytochrome was found to affect the extracellular release of hydrogen peroxide in that a plasma membrane localization was associated with a significantly increased release during phagocytosis. It should be pointed out, however, that most of the hydrogen peroxide, both in control and in ionomycin-treated cells, is produced intracellularly, probably in the phagosomes.     

Reactive Oxygen Species in Peripheral Blood and Sputum Neutrophils During Bacterial and Nonbacterial Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Chronic airway inflammation can be mediated by an enhanced neutrophil oxidative burst. However, the role of bacteria in the pathogenesis of chronic obstructive pulmonary disease (COPD) exacerbations is highly controversial. The aim of this study was to evaluate the production of reactive oxygen species (ROS) in peripheral blood and sputum neutrophils during bacterial and nonbacterial acute exacerbations of COPD (AECOPD). A total of 40 patients with AECOPD, 10 healthy nonsmokers, and 10 “healthy” smokers were enrolled into the study. Peripheral blood and sputum samples were obtained during exacerbation and after recovery. Neutrophils were isolated by high-density gradient centrifugation and magnetic separation. ROS production by neutrophils was investigated after stimulation with phorbol-myristate-acetate and Staphylococcus aureus bacteria. ROS production by neutrophils was assessed as the mean fluorescent intensity using a flow cytometer. IL-8 levels in serum and induced sputum were determinant by ELISA. Spontaneous ROS production was significantly higher in neutrophils from the patients with bacterial AECOPD as compared with nonbacterial AECOPD and stable COPD (P <0.05). ROS production stimulated with PMA and with Staphylococcus aureus was significantly higher in neutrophils isolated from the patients with bacterial AECOPD as compared with nonbacterial and stable COPD (P <0.05). The serum and induced sputum IL-8 levels were significantly increased in the patients with bacterial AECOPD than nonbacterial AECOPD, stable COPS, and “healthy” smokers and nonsmokers (P <0.05) and higher in the induced sputum as the compared with serum in all studied groups (P <0.05). Enlarge CRP level was documented during AECOPD than in all other groups (P <0.05). A markedly increased ROS production in sputum neutrophils during bacterial AECOPD shows an inflammatory response reflecting enhanced local inflammation, which can be mediated by bacterial colonization.     

Evaluation of Level of Agreement in Bordetella Species Identification in Three U.S. Laboratories during a Period of Increased Pertussis

While PCR is the most common method used for detecting Bordetella pertussis in the United States, most laboratories use insertion sequence 481 (IS481), which is not specific for B. pertussis; therefore, the relative contribution of other Bordetella species is not understood. The objectives of this study were to evaluate the proportion of other Bordetella species misidentified as B. pertussis during a period of increased pertussis incidence, determine the level of agreement in Bordetella species detection between U.S. commercial laboratories and the CDC, and assess the relative diagnostic sensitivity of CDC''s PCR assay when using a different PCR master mix. Specimens collected between May 2012 and May 2013 were tested at two U.S. commercial laboratories for B. pertussis and B. parapertussis detection. Every fifth specimen positive for IS481 and/or IS1001 with cycle threshold (C_T) values of ≤35 was sent to CDC for PCR testing that identifies Bordetella species. Specimens with indeterminate or negative results in the CDC PCR were tested using an alternate PCR master mix. Of 755 specimens, there was agreement in species identification for 83.4% (n = 630). Of the specimens with different identifications (n = 125), 79.2% (n = 99) were identified as indeterminate B. pertussis at CDC. Overall, 0.66% (n = 5) of the specimens were identified as B. holmesii or B. bronchiseptica at CDC. Of 115 specimens with indeterminate or negative results, 46.1% (n = 53) were B. pertussis positive when tested by an alternate master mix, suggesting a possible increase in assay sensitivity. This study demonstrates good agreement between the two U.S. commercial laboratories and CDC and little misidentification of Bordetella species during the 2012 U.S. epidemic.     

Functional Insufficiency of the System Responsible for Reactive Oxygen Species Generation by Blood Neutrophils

We studied functional activity of the system responsible for generation of reactive oxygen species by blood neutrophils and involved in pathophysiological mechanisms of bronchopulmonary diseases. Insufficiency of this system can be classified as relative, latent (type I and II), and severe.     

Roles of Reactive Oxygen Species in CXCL8 and CCL2 Expression in Response to the 30-kDa Antigen of <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis>

Background  The 30-kDa antigen (Ag) of Mycobacterium tuberculosis (M. tuberculosis) is a strong inducer of innate and adaptive immune responses in human tuberculosis. The generation of reactive oxygen species (ROS) plays an important role in inflammatory signaling as well as antimicrobial defense. Materials and Methods  In this study, we investigated the role of ROS in the activation of mitogen-activated protein kinases (MAPKs) and secretion of the CXC chemokine ligand 8 (CXCL8) and CC chemokine ligand 2 (CCL2) by human monocytes stimulated with the 30-kDa Ag of M. tuberculosis H37Rv. Results  Treatment of human monocytes with the 30-kDa Ag activated rapid superoxide generation. In addition, the 30-kDa Ag activated mRNA and protein expression of CXCL8 and CCL2 in human primary monocytes through nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent ROS generation. Analysis of MAPK activation (extracellular signal-regulated kinase (ERK) 1/2 and p38) showed rapid phosphorylation of both subfamilies in response to the 30-kDa Ag. In addition, 30-kDa-induced MAPK activation was inhibited in a dose-dependent manner by pretreatment with ROS scavengers. Toll-like receptor (TLR) 2 was required for ROS generation, chemokine production, and MAPK activation following stimulation with the 30-kDa Ag. Using highly specific signaling pathway inhibitors, we found that both p38 and ERK1/2 activation are essential for 30-kDa Ag-induced CCL2 but not CXCL8 production in human monocytes. Conclusion  These results indicate that TLR2–ROS signaling plays a crucial role in the 30-kDa Ag-mediated expression of CXCL8 and CCL2 in human monocytes. In addition, both p38 and ERK1/2 activation are essential for 30-kDa Ag-stimulated CCL2 production by monocytes.     

The Role of Reactive Oxygen Species in Integrin and Matrix Metalloproteinase Expression and Function

Cell adhesion and migration is largely dependent on integrin binding to extracellular matrix, and several signalling pathways involved in these processes have been shown to be modified by reactive oxygen species (ROS). In fact, integrin activation is linked to increased ROS production by NADPH-oxidases, 5-lipoxygenase, and release from mitochondria. Cell migration is intimately linked to degradation of the extracellular matrix, and activated matrix metalloproteinases (MMPs) are a prerequisite for cancer cell invasion and metastasis. In this minireview, we focus on the interplay between integrin-mediated ROS production and MMP expression as well as its biological and pathobiological significance.     

缺氧应激反应中活性氧与缺氧诱导因子-1的相互作用

在缺氧条件下,线粒体会产生大量的活性氧（ reactive oxygen species, ROS）,随即大量的活性氧将会诱导机体产生缺氧应激反应。缺氧诱导因子1（hypoxia inducible factor 1, HIF?1）是缺氧应激反应中的中枢调控因子。有研究表明, ROS主要通过抑制脯氨酸羟化酶家族（ prolyl hydroxylases, PHDs）的活性来抑制HIF?1α的泛素化降解,从而稳定HIF?1。而HIF?1蛋白水平的升高有助于机体应对缺氧微环境。最近研究还发现, REDD?1可以通过ROS对HIF?1产生负调控作用,从而抑制肿瘤的形成;秀丽线虫呼吸突变体的产生会导致ROS水平增加,从而增强HIF?1的活性,最终延长的线虫寿命;以及ROS、 HIF?1促进自噬的产生。因此,了解缺氧条件下ROS与HIF?1之间的相互作用关系,对于今后肿瘤、衰老和自噬的研究具有重要意义。     

Increased Level of Soluble E-Selectin in the Serum from Patients with Idiopathic Pulmonary Fibrosis

To elucidate the biological significance of selectin for idiopathic pulmonary fibrosis, we titrated the serum soluble E-selectin. From 31 cases of idiopathic pulmonary fibrosis patients without signs or symptoms of infection, the serum was obtained and the concentration was titrated by enzyme-linked immunosorbent assay. The serum soluble E-selectin titer was significantly higher than that of healthy controls. However, significant elevation was not observed in the sera from the patients with other pulmonary diseases, such as pulmonary emphysema, sarcoidosis, or bronchiectasis. In the patients with idiopathic pulmonary fibrosis, the number of white blood cells, C-reactive protein or lactate dehydrogenase activity did not show a significant relationship with the soluble E-selectin titer. About 16 out of the 31 idiopathic fibrosis patients, the serum surfactant apoprotein-A titer, which is a parameter of the disease activity of idiopathic pulmonary fibrosis, was also tested. The surfactant apoprotein-A titer was loosely correlated with the soluble E-selectin titer. These observations suggest that E-selectin may be relevant to the pathogenesis of idiopathic pulmonary fibrosis, and it may be a novel clinical parameter for idiopathic pulmonary fibrosis.     

Effects of Peptides on Generation of Reactive Oxygen Species in Subcellular Fractions of Drosophila Melanogaster

We studied the effects of Epithalon (Ala-Glu-Asp-Gly) and Vilon (Lys-Glu) on free radical processes in highly inbred HA⁺line of Drosophila melanogaster. Vilon inhibited generation of reactive oxygen species in mitochondria, but stimulated this process in the cytosol. We found sex- and age-related differences in the generation of reactive oxygen species and cytosol antioxidant activity.     

Regulation of Antioxidants and Phase 2 Enzymes by Shear-Induced Reactive Oxygen Species in Endothelial Cells

Exposure of vascular endothelial cells (ECs) to steady laminar shear stress activates the NF-E2-related factor 2 (Nrf2) which binds to the antioxidant response element (ARE) and upregulates the expression of several genes. The onset of shear is known to increase the EC reactive oxygen species (ROS) production, and oxidative stress can activate the ARE. ARE-regulated genes include phase 2 enzymes, such as glutathione-S-transferase (GST) and NAD(P)H:quinone oxidoreductase 1 (NQO1), and antioxidants, such as glutathione reductase (GR), glutathione peroxidase (GPx) and catalase. We examined how shear stress affects the antioxidant/phase 2 enzyme activities and whether ROS mediate these effects. ROS production, measured by dichlorofluorescin fluorescence, depended on level and time of shear exposure and EC origin, and was inhibited by either an endothelial nitric oxide synthase (eNOS) inhibitor or a superoxide dismutase (SOD) mimetic and peroxynitrite (ONOO⁻) scavenger. Shear stress (10 dynes/cm², 16 h) significantly increased the NQO1 activity, did not change significantly the glutathione (GSH) content, and significantly decreased the GR, GPx, GST and catalase activities in human umbilical vein ECs. Either eNOS inhibition or superoxide radical (O₂^•−)/ONOO⁻ scavenging differentially modulated the shear effects on enzyme activities suggesting that the intracellular redox status coordinates the shear-induced expression of cytoprotective genes.     

活性氧簇介导的氧化应激及细胞焦亡在大鼠脑缺血再灌注损伤中的作用

目的 研究活性氧簇 (ROS) 介导的氧化应激及细胞焦亡在大鼠脑缺血再灌注 ( I/ R) 损伤中的 作用。 方法 成年雄性 SD 大鼠分为假手术 ( Sham) 组、 I/ R 组、 ROS 清除剂 N 乙酰半胱氨酸-低剂量 (NAC-L) 组、 NAC 中等剂量 (NAC-M) 组、 NAC 高剂量 (NAC-H) 组, 建立脑 I/ R 损伤模型并给予 50、 100、 200 mg / kg NAC 腹腔注射干预。 再灌注后 24 h, 评价神经功能, 检测脑梗死面积百分比、 ROS、 丙二 醛 (MDA)、 4-羟基壬烯醛 (4-HNE)、 总抗氧化力 (T-AOC)、 裂解型 caspase-1 (Cleaved caspase-1)、 gasdermin D 的 N 端片段 (GSDMD-N)。 结果 I/ R 组脑梗死面积百分比、 ROS、 MDA、 4-HNE 含量、 Cleaved caspase-1、 GSDMD-N 表达水平均明显增加, T-AOC 含量明显降低 ( P < 0. 05 ); NAC-L 组、 NAC-M 组、 NAC-H 组脑梗死面积百分比、 ROS、 MDA、 4-HNE 含量、 Cleaved caspase-1、 GSDMD-N 表达水平均明显降 低, T-AOC 含量明显增加 (P< 0. 05) 且 NAC 剂量越高, 上述变化越显著。 结论 ROS 介导的氧化应激及 细胞焦亡参与大鼠脑 I/ R 损伤。     

检测妊娠期GD子代血清TRAb的临床价值

目的:探讨母妊娠合并Graves'病的新生儿血清促甲状腺激素受体抗体(TRAb)水平与甲状腺功能关系.方法:采用放射免疫分析(RIA)检测126例妊娠合并Graves'病(毒性弥漫性甲状腺肿)产妇新生儿和40例健康产妇新生儿的FT3、FT4、超敏促甲状腺激素(sTSH),采用电化学发光免疫分析(ECLIA)检测TRAb...     

NADPH氧化酶源性的活性氧在胚胎干细胞分化成心肌细胞的分子机制中的作用

活性氧(reactive oxygen species,ROS)主要包括超氧离子(O2-),过氧化氢(H2O2)和羟自由基(OH-),在心肌细胞中,ROS的产生主要来自膜结合的NADPH氧化酶(NOX)的催化作用,并作为第二信使通过相关信号传导途径双向调节细胞的增殖与死亡。,最近发现ROS在胚胎干细胞(embryonic stem cells,ES)向心肌细胞分化过程中起重要的调节作用。对这些调节机制的研究有利于我们更好地认识ROS及NADPH氧化化酶在心肌细胞分化中的重要作用并有利于我们确定促进心脏分化的因子。     

妊娠期糖尿病与瘦素水平变化的临床研究

目的　探讨瘦素水平与妊娠期糖尿病 (GDM)发病关系以及对其胎儿生长发育的影响。方法　采用放射免疫法测定GDM孕妇 2 0例 ,糖耐量减低 (IGT)孕妇 2 2例 ,正常孕妇 2 5例血清及其新生儿脐血的瘦素水平 ,同时测定这三组孕妇的胰岛素、C肽水平 ,并测量孕前体重指数和孕期体重增加指数 ,分析其与瘦素之间的关系。结果　GDM孕妇血清瘦素、胰岛素和C肽水平明显高于IGT组及正常组 (P <0 .0 0 1)。脐血瘦素水平与胎儿体重呈正相关 (P <0 .0 5 ) 。孕妇血清瘦素水平与胎儿体重无相关。孕妇血清瘦素水平与脐血瘦素水平无相关。GDM孕妇血清瘦素与孕前体重指数明显相关 (P <0 .0 5 ) ,与孕期体重增加指数无相关。结论　 (1)GDM孕妇血清瘦素水平明显高于正常孕妇 ,故瘦素可作为监控GDM的指标之一。(2 )GDM孕妇瘦素水平与脐血瘦素水平虽然不相关 ,提示胎儿瘦素是自身产生 ,但母亲糖尿病也可以影响胎儿产生更多的瘦素。