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1.
Amounts of trehalose-6,6-dimycolate as small as 1 to 5 mug can, after intravenous injection, induce in the lungs of mice formation of tubercles in which the cellular composition is indistinguishable from that in tubercles formed after an infection with living BCG bacilli. The strongest cellular response in mice was induced by cord factor from Mycobacterium kansasii; the weakest was induced by cord factor from the BCG strain of M. bovis. It was found that three intravenous injections of cord factor induced a more extensive cellular response than did one injection of the same total amount of cord factor. Mice treated intravenously with cord factor were protected against an intravenous challenge with the virulent H37Rv strain of M. tuberculosis. The cellular response in the lungs of mice to intraperitoneal injections of living BCG and cord factor was very weak compared with that after intravenous injections. Intraperitoneal vaccination of mice with cord factor did not protect the mice against a challenge with virulent tubercle bacilli. Mice vaccinated intraperitoneally with BCG were immunized although no granulomas, or very few, were present in the lungs at the time of the challenge. The significance of the cellular response induced by cord factor is discussed.  相似文献   

2.
Previous data have indicated that activated macrophages may play a role in the mediation of acetaminophen toxicity. In the present study, we examined the significance of superoxide produced by macrophages by comparing the toxicity of acetaminophen in wild-type mice to mice deficient in gp91phox, a critical subunit of NADPH oxidase that is the primary source of phagocytic superoxide. Both groups of mice were dosed with 300?mg/kg of acetaminophen or saline and sacrificed at 1, 2, 4 or 24?h. Glutathione in total liver and in mitochondria was depleted by approximately 90% at 1?h in wild-type and knock out mice. No significant differences in toxicity (serum transaminase levels or histopathology) were observed between wild-type and mice deficient in gp91phox. Mitochondrial glutathione disulfide, as a percent of total glutathione, was determined as a measure of oxidant stress produced by increased superoxide, leading to hydrogen peroxide and/or peroxynitrite. The percent mitochondrial glutathione disulfide increased to approximately 60% at 1?h and 70% at 2?h in both groups of mice. Immunohistochemical staining for nitrotyrosine was present in vascular endothelial cells at 1?h in both groups of mice. Acetaminophen protein adducts were present in hepatocytes at 1?h in both wild-type and knock out animals. These data indicate that superoxide from activated macrophages is not critical to the development of acetaminophen toxicity and provide further support for the role of mitochondrial oxidant stress in acetaminophen toxicity.  相似文献   

3.
Dual oxidases (DUOX) are enzymes that contain an NADPH oxidase domain that produces hydrogen peroxide (H2O2) and a peroxidase domain that can utilize H2O2 to carry out a variety of reactions. The model organism Caenorhabditis elegans produces the DUOX, BLI-3, which has roles in both cuticle development and in protection against infection. In previous work, we demonstrated that while certain peroxidases were protective against the human bacterial pathogen Enterococcus faecalis, the peroxidase domain of BLI-3 was not, leading to the postulate that the NADPH oxidase domain is the basis for BLI-3’s protective effects. In this work, we show that a strain carrying a mutation in the NADPH oxidase domain of BLI-3, bli-3(im10), is more susceptible to E. faecalis and the human fungal pathogen Candida albicans. Additionally, less H2O2 is produced in response to pathogen using both an established Amplex Red assay and a strain of C. albicans, WT-OXYellow, which acts as a biosensor of reactive oxygen species (ROS). Finally, a C. elegans line containing a BLI-3::mCherry transgene was generated. Previous work suggested that BLI-3 is produced in the hypodermis and the intestine. Expression of the transgene was observed in both these tissues, and additionally in the pharynx. The amount and pattern of localization of BLI-3 did not change in response to pathogen exposure.  相似文献   

4.
Ulcerative colitis (UC) is a chronic inflammatory bowel disease affecting the rectum which progressively extents. Its etiology remains unknown and the number of treatments available is limited. Studies of UC patients have identified an unbalanced endoplasmic reticulum (ER) stress in the non-inflamed colonic mucosa. Animal models with impaired ER stress are sensitive to intestinal inflammation, suggesting that an unbalanced ER stress could cause inflammation. However, there are no ER stress-regulating strategies proposed in the management of UC partly because of the lack of relevant preclinical model mimicking the disease. Here we generated the IL10/Nox1dKO mouse model which combines immune dysfunction (IL-10 deficiency) and abnormal epithelium (NADPH oxidase 1 (Nox1) deficiency) and spontaneously develops a UC-like phenotype with similar complications (colorectal cancer) than UC. Our data identified an unanticipated combined role of IL10 and Nox1 in the fine-tuning of ER stress responses in goblet cells. As in humans, the ER stress was unbalanced in mice with decreased eIF2α phosphorylation preceding inflammation. In IL10/Nox1dKO mice, salubrinal preserved eIF2α phosphorylation through inhibition of the regulatory subunit of the protein phosphatase 1 PP1R15A/GADD34 and prevented colitis. Thus, this new experimental model highlighted the central role of epithelial ER stress abnormalities in the development of colitis and defined the defective eIF2α pathway as a key pathophysiological target for UC. Therefore, specific regulators able to restore the defective eIF2α pathway could lead to the molecular remission needed to treat UC.  相似文献   

5.
The role of the reactive oxygen species-producing NADPH oxidase family of enzymes in the pathology of influenza A virus infection remains enigmatic. Previous reports implicated NADPH oxidase 2 in influenza A virus-induced inflammation. In contrast, NADPH oxidase 1 (Nox1) was reported to decrease inflammation in mice within 7 days post-influenza A virus infection. However, the effect of NADPH oxidase 1 on lethality and adaptive immunity after influenza A virus challenge has not been explored. Here we report improved survival and decreased morbidity in mice with catalytically inactive NADPH oxidase 1 (Nox1*/Y) compared with controls after challenge with A/PR/8/34 influenza A virus. While changes in lung inflammation were not obvious between Nox1*/Y and control mice, we observed alterations in the T cell response to influenza A virus by day 15 post-infection, including increased interleukin-7 receptor-expressing virus-specific CD8+ T cells in lungs and draining lymph nodes of Nox1*/Y, and increased cytokine-producing T cells in lungs and spleen. Furthermore, a greater percentage of conventional and interstitial dendritic cells from Nox1*/Y draining lymph nodes expressed the co-stimulatory ligand CD40 within 6 days post-infection. Results indicate that NADPH oxidase 1 modulates the innate and adaptive cellular immune response to influenza virus infection, while also playing a role in host survival. Results suggest that NADPH oxidase 1 inhibitors may be beneficial as adjunct therapeutics during acute influenza infection.  相似文献   

6.
The X+-linked chronic granulomatous disease (X+-CGD) variants are natural mutants characterized by defective NADPH oxidase activity but with normal Nox2 expression. According to the three-dimensional model of the cytosolic Nox2 domain, most of the X+-CGD mutations are located in/or close to the FAD/NADPH binding regions. A structure/function study of this domain was conducted in X+-CGD PLB-985 cells exactly mimicking 10 human variants: T341K, C369R, G408E, G408R, P415H, P415L, Δ507QKT509-HIWAinsert, C537R, L546P, and E568K. Diaphorase activity is defective in all these mutants. NADPH oxidase assembly is normal for P415H/P415L and T341K mutants where mutation occurs in the consensus sequences of NADPH- and FAD-binding sites, respectively. This is in accordance with their buried position in the three-dimensional model of the cytosolic Nox2 domain. FAD incorporation is abolished only in the T341K mutant explaining its absence of diaphorase activity. This demonstrates that NADPH oxidase assembly can occur without FAD incorporation. In addition, a defect of NADPH binding is a plausible explanation for the diaphorase activity inhibition in the P415H, P415L, and C537R mutants. In contrast, Cys-369, Gly-408, Leu-546, and Glu-568 are essential for NADPH oxidase complex assembly. However, according to their position in the three-dimensional model of the cytosolic domain of Nox2, only Cys-369 could be in direct contact with cytosolic factors during oxidase assembly. In addition, the defect in oxidase assembly observed in the C369R, G408E, G408R, and E568K mutants correlates with the lack of FAD incorporation. Thus, the NADPH oxidase assembly process and FAD incorporation are closely related events essential for the diaphorase activity of Nox2.  相似文献   

7.
As the terminal component of the mitochondrial respiratory chain, cytochrome c oxidase plays a vital role in cellular energy transformation. Human cytochrome c oxidase is composed of 13 subunits. The three major subunits form the catalytic core and are encoded by mitochondrial DNA (mtDNA). The remaining subunits are nuclear-encoded. The primary sequence is known for all human subunits and the crystal structure of bovine heart cytochrome c oxidase has recently been reported. However, despite this wealth of structural information, the role of the nuclear-encoded subunits is still poorly understood. Yeast cytochrome c oxidase is a close model of its human counterpart and provides a means of studying the effects of mutations on the assembly, structure, stability and function of the enzyme complex. Defects in cytochrome c oxidase function are found in a clinically heterogeneous group of disorders. The molecular defects that underlie these diseases may arise from mutations of either the mitochondrial or the nuclear genomes or both. A significant number of cytochrome c oxidase deficiencies, often associated with other respiratory chain enzyme defects, are attributed to mutations of mtDNA. Mutations of mtDNA appear, nonetheless, uncommon in early childhood. Pedigree analysis and cell fusion experiments have demonstrated a nuclear involvement in some infantile cases but a specific nuclear genomic lesion has not yet been reported. Detailed analyses of the many steps involved in the biogenesis of cytochrome c oxidase, often pioneered in yeast, offer several starting points for further molecular characterizations of cytochrome c oxidase deficiencies observed in clinical practice.  相似文献   

8.
Despite a plethora of literature has documented that osteoarthritis (OA) is veritably associated with oxidative stress-mediated chondrocyte death and matrix degradation, yet the possible involvement of synoviocyte abnormality as causative factor of OA has not been thoroughly investigated. For this reason, we conduct the current studies to insight into how synoviocytes could respond to an episode of folate-deprived (FD) condition. First, when HIG-82 synoviocytes were cultivated under FD condition, a time-dependent growth impediment was observed and the demise of these cells was demonstrated to be apoptotic in nature mediated through FD-evoked overproduction of reactive oxygen species (ROS) and drastically released of cytosolic calcium (Ca2+) concentrations. Next, we uncovered that FD-evoked ROS overproduction could only be strongly suppressed by either mitochondrial complex II inhibitors (TTFA and carboxin) or NADPH oxidase (NOX) inhibitors (AEBSF and apocynin), but not by mitochondrial complex I inhibitor (rotenone) and mitochondrial complex III inhibitor (antimycin A). Interestingly, this selective inhibition of FD-evoked ROS by mitochondrial complex II and NOX inhibitors was found to correlate excellently with the suppression of cytosolic Ca2+ release and reduced the magnitude of the apoptotic TUNEL-positive cells. Taken together, we present the first evidence here that FD-triggered ROS overproduction in synoviocytes is originated from mitochondrial complex II and NOX. Both elevated ROS in tandem with cytosolic Ca2+ overload serve as final arbitrators for apoptotic lethality of synoviocytes cultivated under FD condition. Thus, folate supplementation may be beneficial to patients with OA.  相似文献   

9.
10.
Infections, microbe sampling and occasional leakage of commensal microbiota and their products across the intestinal epithelial cell layer represent a permanent challenge to the intestinal immune system. The production of reactive oxygen species by NADPH oxidase is thought to be a key element of defense. Patients suffering from chronic granulomatous disease are deficient in one of the subunits of NADPH oxidase. They display a high incidence of Crohn’s disease-like intestinal inflammation and are hyper-susceptible to infection with fungi and bacteria, including a 10-fold increased risk of Salmonellosis. It is not completely understood which steps of the infection process are affected by the NADPH oxidase deficiency. We employed a mouse model for Salmonella diarrhea to study how NADPH oxidase deficiency (Cybb −/−) affects microbe handling by the large intestinal mucosa. In this animal model, wild type S. Typhimurium causes pronounced enteropathy in wild type mice. In contrast, an avirulent S. Typhimurium mutant (S.Tmavir; invGsseD), which lacks virulence factors boosting trans-epithelial penetration and growth in the lamina propria, cannot cause enteropathy in wild type mice. We found that Cybb −/− mice are efficiently infected by S.Tmavir and develop enteropathy by day 4 post infection. Cell depletion experiments and infections in Cybb −/− Myd88 −/− mice indicated that the S.Tmavir-inflicted disease in Cybb −/− mice hinges on CD11c+CX3CR1+ monocytic phagocytes mediating colonization of the cecal lamina propria and on Myd88-dependent proinflammatory immune responses. Interestingly, in mixed bone marrow chimeras a partial reconstitution of Cybb-proficiency in the bone marrow derived compartment was sufficient to ameliorate disease severity. Our data indicate that NADPH oxidase expression is of key importance for restricting the growth of S.Tmavir in the mucosal lamina propria. This provides important insights into microbe handling by the large intestinal mucosa and the role of NADPH oxidase in maintaining microbe-host mutualism at this exposed body surface.  相似文献   

11.
The NLR gene family mediates host immunity to various acute pathogenic stimuli, but its role in chronic infection is not known. This paper addressed the role of NLRP3 (NALP3), its adaptor protein PYCARD (ASC), and caspase-1 during infection with Mycobacterium tuberculosis (Mtb). Mtb infection of macrophages in culture induced IL-1β secretion, and this requires the inflammasome components PYCARD, caspase-1, and NLRP3. However, in vivo Mtb aerosol infection of Nlrp3−/−, Casp-1−/−, and WT mice showed no differences in pulmonary IL-1β production, bacterial burden, or long-term survival. In contrast, a significant role was observed for Pycard in host protection during chronic Mtb infection, as shown by an abrupt decrease in survival of Pycard−/− mice. Decreased survival of Pycard−/− animals was associated with defective granuloma formation. These data demonstrate that PYCARD exerts a novel inflammasome-independent role during chronic Mtb infection by containing the bacteria in granulomas.  相似文献   

12.
Wheat coleoptile tips generate superoxide radical as a part of the phototropic response to blue light, but the source of this free radical generation is not known. We evaluated the presence and involvement of homologs of neutrophil NADPH oxidase (NOX), including gp91phox, p22phox, p67phox, p47phox, and p40phox, in wheat coleoptiles using Western blot analysis and immunofluorescence microscopy. Blue light augmented the expression levels of all these subunits and targeted NOX subunits onto the plasma membrane and to the nucleus. gp91phox, p22phox, p67phox, and p40phox showed entry into the nucleus and exhibited physical closeness with DNA. CuZnSOD was also present in the coleoptile tip, which also showed a blue-light-dependent elevation in expression. Superoxide production and phototropic response were both abrogated by DPIC and staurosporine, indicating their cause-and-effect relationship. We conclude that blue light mediates a phototropic response in wheat coleoptiles through modulation of expression of NOX and SOD as well as the translocation of NOX subunits onto the plasma membrane and nuclear membrane. Thus, this study provides a mechanistic explanation for superoxide production during the photoresponse in wheat coleoptiles.  相似文献   

13.
The NADPH oxidase of phagocytic cells of the immune system plays an important role in the destruction of certain types of microbial pathogens during infections. Its inappropriate activation to release reactive oxidants may also contribute to host tissue damage in inflammatory diseases. In this review, the structure of the NADPH oxidase is described and many of the commonly used methods to detect its activation during the respiratory burst are listed. The advantages and disadvantages of each of these methods are critically discussed.  相似文献   

14.
The dopaminergic system appears early in mammalian brain development, and a neurodevelopmental role for dopamine (DA) has been suggested. In the present study, we found that DA markedly promoted the survival of embryonic striatal cells in cultures. The failure of DA receptor antagonists to block this survival-promoting effect and the capability of S-apomorphine, which is devoid of DA receptor agonist activity but possesses antioxidative activity as R-apomorphine and DA, to completely mimic this effect suggested that DA receptor activation was not required in the survival-promoting effect elicited by DA, and its antioxidative activity might be involved. Moreover, it was found that mRNA of NADPH oxidase was expressed in the embryonic striatum. Furthermore, DPI or apocynin, NADPH oxidase inhibitors, promoted the survival of embryonic striatal cells. Addition of either DA or DPI into striatal cell cultures decreased the superoxide level. These results indicate that the mechanisms underlying the neuroprotective effects of DA were likely associated with its antioxidative activity. NADPH oxidase might contribute, at least in part, to ROS generation.  相似文献   

15.
16.
为了探讨小分子GTP酶蛋白Rac1和Rac2在人单核细胞中趋化迁移以及还原型辅酶II(NADPH)氧化酶活性中的作用,采用小分子干扰siRNA对人单核细胞中RAC1、RAC2分别进行特异性抑制,采用实时定量PCR技术、免疫印迹技术在RNA和蛋白质水平上确认抑制效果,使用甲酰三肽(formyl-met-leu-phe,fMLP)、人单核细胞趋化因子(monocyte chemoattractant protein-1,MCP-1)诱导单核细胞趋化;用血清调理的酵母多糖(serum opsonized zymosan,ZOP)、佛波酯(phosphomolybdic acid, PMA)激活单核细胞NADPH氧化酶活性,诱导活性氧(Reactive oxygen species, ROS)产生,以此对Rac1和Rac2作用进行研究. 结果表明,小分子干扰siRNA能够在mRNA水平和蛋白质水平分别有效抑制目的基因表达;使用Chamber assay方法发现,仅Rac1参与了fMLP、MCP-1诱导的人单核细胞趋化. Rac激活实验确证,Rac1参与MCP-1诱导的趋化;细胞色素C还原法表明,Rac1和Rac2均参与PMA和ZOP诱导人单核细胞ROS生成. 在人单核细胞中,RAC1和RAC2基因沉默模型的成功建立以及初步研究显示,Rac1和Rac2的不同作用结果将为深入研究它们在人单核细胞中的功能奠定了良好基础.  相似文献   

17.
Genes encoding homologs of the gp91(phox) subunit of the plasma membrane NADPH oxidase complex have been identified in plants and are hypothesized to be a source of reactive oxygen species during defense responses. However, the direct involvement of the gene products in superoxide (O(2)(-)) production has yet to be shown. A novel activity gel assay based on protein fractionation in native or sodium dodecyl sulfate (SDS)-denaturing polyacrylamide gels was developed. In native polyacrylamide gel electrophoresis, one or two major O(2)(-)-producing formazan bands were detected in tomato (Lycopersicum esculentum Mill. cv Moneymaker) and tobacco (Nicotiana tabacum var. Samsun, NN) plasma membranes, respectively. Denaturing fractionation of tomato and tobacco plasma membrane in SDS-polyacrylamide gel electrophoresis, followed by regeneration of the in-gel activity, revealed NADPH-dependent O(2)(-)-producing formazan bands of 106-, 103-, and 80- to 75-kD molecular masses. The SDS and native activity bands were dependent on NADPH and completely inhibited by diphenylene iodonium or CuZn- O(2)(-) dismutase, indicating that the formazan precipitates were due to reduction by O(2)(-) radicals catalyzed by an NADPH-dependent flavin containing enzyme. The source of the plasma membrane activity bands was confirmed by their cross-reaction with antibody prepared from the C terminus of the tomato gp91(phox) homolog. Membrane extracts as well as the in-gel NADPH oxidase activities were stimulated in the presence of Ca(2+). In addition, the relative activity of the gp91(phox) homolog was enhanced in the plasma membrane of tobacco mosaic virus-infected leaves. Thus, in contrast to the mammalian gp91(phox), the plant homolog can produce O(2)(-) in the absence of additional cytosolic components and is stimulated directly by Ca(2+).  相似文献   

18.
The CD38-ADP-ribosylcyclase-mediated Ca2+ signaling pathway importantly contributes to the vasomotor response in different arteries. Although there is evidence indicating that the activation of CD38-ADP-ribosylcyclase is associated with CD38 internalization, the molecular mechanism mediating CD38 internalization and consequent activation in response to a variety of physiological and pathological stimuli remains poorly understood. Recent studies have shown that CD38 may sense redox signals and is thereby activated to produce cellular response and that the NADPH oxidase isoform, NOX1, is a major resource to produce superoxide (O2 ·−) in coronary arterial myocytes (CAMs) in response to muscarinic receptor agonist, which uses CD38-ADP-ribosylcyclase signaling pathway to exert its action in these CAMs. These findings led us hypothesize that NOX1-derived O2 ·− serves in an autocrine fashion to enhance CD38 internalization, leading to redox activation of CD38-ADP-ribosylcyclase activity in mouse CAMs. To test this hypothesis, confocal microscopy, flow cytometry and a membrane protein biotinylation assay were used in the present study. We first demonstrated that CD38 internalization induced by endothelin-1 (ET-1) was inhibited by silencing of NOX1 gene, but not NOX4 gene. Correspondingly, NOX1 gene silencing abolished ET-1-induced O2 ·− production and increased CD38-ADP-ribosylcyclase activity in CAMs, while activation of NOX1 by overexpression of Rac1 or Vav2 or administration of exogenous O2 ·− significantly increased CD38 internalization in CAMs. Lastly, ET-1 was found to markedly increase membrane raft clustering as shown by increased colocalization of cholera toxin-B with CD38 and NOX1. Taken together, these results provide direct evidence that Rac1-NOX1-dependent O2 ·− production mediates CD38 internalization in CAMs, which may represent an important mechanism linking receptor activation with CD38 activity in these cells.  相似文献   

19.
以烟草悬浮细胞BY-2(Nicotiana tabacum L.cv.Bright Yellow-2)为材料,探讨了在铜离子胁迫下植物细胞死亡发生过程中胞外H2O2及NADPH氧化酶所扮演的角色。实验结果表明,随着外源CuCl2浓度的上升(从0~700 μmol·L-1),细胞死亡水平不断上升,且胞外H2O2的水平也不断增加。在300 μmol·L-1的CuCl2诱导细胞死亡的过程中,加入H2O2清除剂N-N-二甲基硫脲(DMTU)降低了胞外CuCl2胁迫下H2O2含量增加的同时也降低了细胞死亡水平的上升,这一观察表明了铜离子胁迫所导致的细胞死亡的发生和胞外H2O2的增加有关。进一步的研究表明,300 μmol·L-1 CuCl2的胁迫导致了NADPH氧化酶活性的显著性上升,而加入NADPH氧化酶的抑制剂(二亚苯基碘,DPI,)则降低了CuCl2胁迫所导致的细胞死亡和胞外H2O2含量的上升。上述结果表明,胞外H2O2和NADPH氧化酶参与了CuCl2对植物细胞死亡的诱导作用。  相似文献   

20.
缺血再灌注损伤为心肌梗死,器官移植,肠道灌注不足,脑中风等疾病或手术的常见并发症,是导致危重病人死亡的重要因素,然而至今临床上仍未有十分理想的治疗方法。在组织缺血再灌注过程中,中性粒细胞通过NADPH(Nicotinamide-adenine dinucleotide phosphate)氧化酶的活化产生大量活性氧(Reactive oxygen species,ROS),一方面参与氧化应激,另一方面进一步招募中性粒细胞,扩大炎症反应,造成组织损伤。本文综述了国外期刊报道的中性粒细胞NADPH氧化酶与组织缺血再灌注损伤的相关研究进展,以期为心脑血管等重大疾病防治提供一定线索。  相似文献   

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