Differential cell surface recruitment of the superoxide‐producing NADPH oxidases Nox1, Nox2 and Nox5: The role of the small GTPase Sar1

Transmembrane glycoproteins, synthesized at the endoplasmic reticulum (ER), generally reach the Golgi apparatus in COPII‐coated vesicles en route to the cell surface. Here, we show that the bona fide nonglycoprotein Nox5, a transmembrane superoxide‐producing NADPH oxidase, is transported to the cell surface in a manner resistant to co‐expression of Sar1 (H79G), a GTP‐fixed mutant of the small GTPase Sar1, which blocks COPII vesicle fission from the ER. In contrast, Sar1 (H79G) effectively inhibits ER‐to‐Golgi transport of glycoproteins including the Nox5‐related oxidase Nox2. The trafficking of Nox2, but not that of Nox5, is highly sensitive to over‐expression of syntaxin 5 (Stx5), a t‐SNARE required for COPII ER‐to‐Golgi transport. Thus, Nox2 and Nox5 mainly traffic via the Sar1/Stx5‐dependent and ‐independent pathways, respectively. Both participate in Nox1 trafficking, as Nox1 advances to the cell surface in two differentially N‐glycosylated forms, one complex and one high mannose, in a Sar1/Stx5‐dependent and ‐independent manner, respectively. Nox2 and Nox5 also can use both pathways: a glycosylation‐defective mutant Nox2 is weakly recruited to the plasma membrane in a less Sar1‐dependent manner; N‐glycosylated Nox5 mutants reach the cell surface in part as the complex form Sar1‐dependently, albeit mainly as the high‐mannose form in a Sar1‐independent manner.     

NADPH oxidase derived reactive oxygen species are involved in human neutrophil IL‐1β secretion but not in inflammasome activation

Neutrophils are essential players in acute inflammatory responses. Upon stimulation, neutrophils activate NADPH oxidase, generating an array of reactive oxygen species (ROS). Interleukin‐1 beta (IL‐1β) is a major proinflammatory cytokine synthesized as a precursor that has to be proteolytically processed to become biologically active. The role of ROS in IL‐1β processing is still controversial and has not been previously studied in neutrophils. We report here that IL‐1β processing in human neutrophils is dependent on caspase‐1 and on the serine proteases elastase and/or proteinase 3. NADPH oxidase deficient neutrophils activated caspase‐1 and did not exhibit differences in NALP3 expression, indicating that ROS are neither required for inflammasome activation nor for its priming, as has been reported for macrophages. Strikingly, ROS exerted opposite effects on the processing and secretion of IL‐1β; whereas ROS negatively controlled caspase‐1 activity, as reported in mononuclear phagocytes, ROS were found to be necessary for the exportation of mature IL‐1β out of the cell, a role never previously described. The complex ROS‐mediated regulation of neutrophil IL‐1β secretion might constitute a physiological mechanism to control IL‐1β‐dependent inflammatory processes where neutrophils play a crucial role.     

Cell-mediated immunity to cytomegalovirus (CMV) and herpes simplex virus (HSV) antigens in the acquired immune deficiency syndrome: Interleukin-1 and interleukin-2 modifyin vitro responses

Peripheral blood lymphocytes (PBL) were obtained from five patients with the acquired immune deficiency syndrome (AIDS), six homosexual males with lymphadenopathy, and five normal heterosexual controls. Modulation of virus-specific immunity was assayedin vitro by measuring the lymphocyte blastogenic response and the production of lymphokine (leukocyte inhibition factor; LIF) by PBL stimulated with herpes simplex virus (HSV) or cytomegalovirus (CMV) antigens in the presence or absence of interleukin-1 (IL-1) and interleukin-2 (IL-2). PBL from the control and lymphadenopathy subjects responded to both antigens in the lymphocyte transformation assay (LT) measured on day 7, and the responses were significantly enhanced in cultures grown in the presence of antigen and IL-2 (1 U/ml). PBL from the AIDS patients were unresponsive, but responsiveness was restored by the addition of IL-2. The addition of IL-1 (0.02 µg/ml) to antigen-stimulated PBL cultures failed to enhance the proliferative responses in all three study groups. LIF production was assayed in the supernatants from day 1 PBL cultures. LIF was not produced by PBL from AIDS patients grown in the presence of viral antigens, whereas three of five patients from the lymphadenopathy group, and three of five control subjects gave rise to positive responses. The addition of IL-1 to the antigenstimulated cultures enhanced LIF production in the control and lymphadenopathy groups but not in the AIDS patients. The addition of IL-2 did not modulate LIF production by antigen-stimulated PBL from the control oR AIDS patients while suppressing the LIF response of the similarly stimulated PBL from the lymphadenopathy patients.     

Expression and function of B7-1 (CD80) and B7-2 (CD86) on human epidermal Langerhans cells

In addition to T cell receptor triggering, activation of T cells requires co-stimulatory signals that have been shown to be mainly initiated through CD28. We analyzed the expression and function of the two ligands for CD28, B7-1 (CD80) and B7-2 (CD86), on human Langerhans cells (LC), the antigen-presenting cells from epidermis. Human LC freshly isolated from epidermis (fLC) expressed significant level of B7-2, which was increased upon a short culture in vitro. In contrast, B7-1 was undetectable on fLC but appeared at the cell surface after a 3-day culture in vitro. Pre-incubation of 18-h cultured LC with anti-B7-2 monoclonal antibodies (mAb) was sufficient to abrogate the binding of CTLA4-Ig fusion protein, while a combination of both mAb against B7-1 and B7-2 was necessary to obtain a complete inhibition of CTLA4-Ig binding on 3-day cultured LC, showing the absence of a third CTLA4 ligand. The function of B7-1 and B7-2 on human LC has been analyzed by adding mAb at the beginning of mixed epidermal cell lymphocyte reactions. Anti-B7-2 mAb and CTLA4-Ig, but not anti-B7-1 mAb, strongly inhibited allogeneic, as well as recall antigen-induced T cell proliferation supported by fLC or 3-day cultured LC. Collectively, these results demonstrate that B7-2 is the major ligand for CD28/CTLA4 at the LC surface and that it plays a crucial role in human LC co-stimulatory function with little, if any, dependence on B7-1 expression.     

Computer prediction of antigenic and topogenic domains in HSV-1 and HSV-2 glycoprotein B (gB)

The envelope glycoprotein B (gB) coded for by the herpes simplex virus type 1 (HSV-1) U_L27 gene is similar to the amino acid (aa) sequence of the gB coded by a homologous gene in HSV-2 DNA. The putative antigenic domains in HSV-1 and HSV-2 gB glycoproteins were analyzed on a comparative basis by suitable computer programs, which allowed the prediction of putative antigenic and topogenic domains. The computer-derived domains were compared to experimentally reported antigenic domains in HSV-1 gB glycoprotein. The computer-predicted antigenic domains in the HSV-1 gB glycoprotein matched well with the reported experimentally derived antigenic domains. The aa sequence of antigenic domain 1 was noted to resemble the amino acid sequence in ApoE that is involved in the attachment of this protein to LDL receptors. The clusters of hydrophobic aa domains are conserved in the two viral glycoproteins and are signals for transfer of the viral proteins through the cellular membrane.     

Sialidosis type 2 (acid neuraminidase deficiency): clinical and biochemical features of a further case

A further patient with a presumed primary deficiency of sialidase N-acetylneuraminic acid hydrolase EC 3.2.1.18) is described. Clinically the patient falls into the sialidosis type 2 category of the recent classification of Lowden & O'Brien (1979), i.e. he manifests coarse facies, mental retardation and skeletal changes of dysostosis multiplex as well as myoclonus and a cherry-red spot at the macula. Sialidase activity in fibroblasts was 4% of control values using a methylumbelliferone substrate. The father of the patient was found to have 50% activity. Abnormal amounts of sialyloligosaccharides were found in the urine. The electrophoretic mobility of known glycosylated enzymes and proteins was found to be altered (more anodal than usual), but could be corrected by incubation of the cell extracts with bacterial neuraminidase. The relationship of the present patient to the Lowden & O'Brien classification is discussed.     

妊高征患者外周血红细胞免疫功能的变化和血浆TXB2水平的相关性分析

目的:探讨妊高征患者外周血红细胞免疫功能的变化和血浆TXB2水平的相关性.方法:应用放射免疫分析和免疫法对33例妊高征患者进行红细胞免疫功能和血浆TXB2检测,并与35名正常人作比较.结果:妊高征患者RBC-C3bRR水平明显降低(P<0.01),而血浆TXB2水平显著升高(P<0.01),RBC-C3bRR与TXB2...     

Characterization of CoCl2-induced reactive oxygen species (ROS): Inductions of neurite outgrowth and endothelin-2/vasoactive intestinal contractor in PC12 cells by CoCl2 are ROS dependent, but those by MnCl2 are not

CoCl(2) and MnCl(2) are hypoxic mimetic agents. We previously found that expression of ET-2/VIC, one of hypoxia-related factors, and the induction of neurite outgrowth in PC12 cells through ROS induced by CoCl(2). MnCl(2) also are known to induce neurite outgrowth in PC12 cells. However, it is unclear whether the mechanism of the effect induced by these metals is same. In the present study, we evaluated biological effects induced by MnCl(2) and compared with those induced by CoCl(2). Furthermore, we analyzed sources of CoCl(2)-induced ROS generation. MnCl(2) up-regulated ET-2/VIC gene expression and ET-2/VIC peptide production as CoCl(2) did, but not affect ET-1 gene expression, in the neurite outgrowth of PC12 cells. NAC did not at all inhibit the effects induced by MnCl(2). Furthermore, addition of MnCl(2) to the culture medium did not generate ROS as CoCl(2) did. These results indicate that ET-2/VIC expression is a common pathway in neurite outgrowth induced by CoCl(2) and MnCl(2), but the effects induced by CoCl(2) are ROS dependent, whereas the effects induced by MnCl(2) are ROS independent. Taken together, the mechanism for the effects by CoCl(2) was different from that by MnCl(2). The ROS, were not decomposed by catalase or SOD, were rapidly generated by reaction of CoCl(2) mainly with components of HS rather than with FBS or DMEM. Some ROS generated by reaction of CoCl(2) with components of HS may participate in the observed neurite outgrowth of PC12 cells.     

In vitro immune responses to hepatitis B surface antigen (pre-S2 and S) following remote infection by hepatitis B virus in humans

In this report we evaluate the human immune response to hepatitis B surface antigen (HBsAg) following remote infection with hepatitis B virus (HBV). HBsAg-reactive lymphocytes can be readily demonstrated in the peripheral blood of individuals with established immunity following infection with HBV.In vitro stimulation with small doses of plasma-derived HBsAg, yeast-derived HBsAg (S region) or pre-S2 peptide will induce specific IgG to HBsAg (anti-HBs) in the absence of a polyclonal increase in total IgG. The pre-S2 peptide will stimulate, in a T cell-dependent fashion, thein vitro production of anti-HBs with specificity for the S domain. This anti-HBs production is mediated by pre-S2-stimulated soluble T-cell factors. Peripheral blood mononuclear cells from individuals with established immunity proliferate to the yeast-derived HBsAg but not to the plasma-derived HBsAg or pre-S2 peptide. The chronic HBsAg carriers do not produce anti-HBs following stimulation with HBsAg regardless of the source or component of antigen used. Different study protocols failed to demonstrate HBsAg-specific responses in the peripheral blood mononuclear cells of chronic carriers.     

Synthesis and Characterization of Hyperbranched Poly(arylene ether)s from a New Activated Trifluoro B3 Monomer Adopting an A2 + B3 Approach

A new trifluoromethyl‐activated trifluoro monomer was successfully prepared by Pd‐initiated coupling of 1,3,5‐tribromobenzene with 4‐fluoro‐3‐trifluoromethylphenylboronic acid. 1,3,5‐Tris(4‐fluoro‐3‐trifluoromethylphenyl)benzene ( B ₃ ) leads to several hyperbranched poly(arylene ether)s when reacted with three different bisphenols ( A ₂ ) in different molar ratios. The 1.5:1 molar product of A ₂ / B ₃ showed very high molecular weight without significant gelation. The products have been well characterized by GPC, DSC, TGA, FTIR, and NMR techniques. The ¹⁹F NMR signals were used to calculate the degree of branching. The 1.5:1 molar products have excellent thermal stability and higher glass transition temperatures than their linear analogs.

     

Genetic variants of immunoglobulin γ and κ chains influence humoral immunity to the cancer‐testis antigen XAGE‐1b (GAGED2a) in patients with non‐small cell lung cancer

GM (γ marker) allotypes, genetic variants of immunoglobulin γ chains, have been reported to be associated strongly with susceptibility to lung cancer, but the mechanism(s) underlying this association is not known. One mechanism could involve their contribution to humoral immunity to lung tumour‐associated antigens. In this study, we aimed to determine whether particular GM and KM (κ marker) allotypes were associated with antibody responsiveness to XAGE‐1b, a highly immunogenic lung tumour‐associated cancer‐testis antigen. Sera from 89 patients with non‐small cell lung cancer (NSCLC) were allotyped for eight GM and two KM determinants and characterized for antibodies to a synthetic XAGE‐1b protein. The distribution of various GM phenotypes was significantly different between XAGE‐1b antibody‐positive and ‐negative patients (P = 0·023), as well as in the subgroup of XAGE‐1b antigen‐positive advanced NSCLC (P = 0·007). None of the patients with the GM 1,17 21 phenotype was positive for the XAGE‐1b antibody. In patients with antigen‐positive advanced disease, the prevalence of GM 1,2,17 21 was significantly higher in the antibody‐positive group than in those who lacked the XAGE‐1b antibody (P = 0·026). This phenotype also interacted with a particular KM phenotype: subjects with GM 1,2,17 21 and KM 3,3 phenotypes were almost four times (odds ratio = 3·8) as likely to be positive for the XAGE‐1b antibody as the subjects who lacked these phenotypes. This is the first report presenting evidence for the involvement of immunoglobulin allotypes in immunity to a cancer‐testis antigen, which has important implications for XAGE‐1b‐based immunotherapeutic interventions in lung adenocarcinoma.     

An emerging role of neutrophils and NETosis in chronic inflammation and fibrosis in systemic lupus erythematosus (SLE) and ANCA-associated vasculitides (AAV): Implications for the pathogenesis and treatment

Neutrophils derive from hematopoietic stem cells (HSCs) with systemic inflammation driving their activation and differentiation to myeloid progenitors to ensure enhanced myelopoiesis. Epigenetic reprograming and re-education of these HSCs produces neutrophils primed towards elimination of pathogens and increased inflammatory response. Neutrophils -an important component of acute inflammation- are not present in chronic inflammatory tissues leading to the false assumption that they may not be as important for the latter. Activated neutrophils may release Neutrophil Extracellular Traps (NETs) during a distinct form of cell death, named NETosis; NETs are rich in bioactive molecules that promote thrombosis (including atherothrombosis), inflammation and fibrosis. Thus, although neutrophils may not be present in chronic inflammatory lesions, their remnants may amplify the inflammatory response beyond their short life-span in the tissues. Herein, we review current evidence supporting a role of neutrophils and NETosis in tissue injury and dysfunction in systemic autoimmunity using as disease paradigms Systemic Lupus Erythematosus (SLE) and the ANCA-associated vasculitides (AAV). We also discuss the mechanisms involved and their potential as targets for novel therapy and drug repositioning.     

DL-3-n-Butylphthalide protects rat bone marrow stem cells against hydrogen peroxide-induced cell death through antioxidation and activation of PI3K-Akt pathway

Bone marrow stem cells (BMSCs) have been one of the most important cell sources for cell replacement therapy (CRT) in cerebral infarction. However, long-lasting oxidative stress during stroke, which plays an important role in neuron damage, deteriorates the microenvironment for cell survival, differentiation and removal. Thus the outcome of CRT in ischemic diseases was poor. DL-3-n-Butylphthalide (NBP) has protective effects on ischemic brain tissue through multiple mechanisms and has been used for stroke treatment in China for several years. In this study, hydrogen peroxide (H(2)O(2)) was used to induce oxidative stress injury to rat bone marrow stem cells (rBMSCs), imitating the microenvironment surrounding transplanted cells in the ischemic brain in vitro. The protective effects of NBP on rBMSCs against apoptosis induced by oxidative stress were investigated. Our results indicated that NBP could protect rBMSCs against apoptosis due to antioxidative properties and modulation of PI3K/Akt pathway. NBP could be used in combination with BMSCs for the treatment of cerebral infarction by improving the oxidative stress microenvironments and cell survival, however, further studies remain warranted.