The chemokine receptor CXCR2 and coronavirus-induced neurologic disease.

Inoculation with the neurotropic JHM strain of mouse hepatitis virus (MHV) into the central nervous system (CNS) of susceptible strains of mice results in an acute encephalomyelitis in which virus preferentially replicates within glial cells while excluding neurons. Control of viral replication during acute disease is mediated by infiltrating virus-specific T cells via cytokine secretion and cytolytic activity, however sterile immunity is not achieved and virus persists resulting in chronic neuroinflammation associated with demyelination. CXCR2 is a chemokine receptor that upon binding to specific ligands promotes host defense through recruitment of myeloid cells to the CNS as well as protecting oligodendroglia from cytokine-mediated death in response to MHV infection. These findings highlight growing evidence of the diverse and important role of CXCR2 in regulating neuroinflammatory diseases

The Periotest Method: Implant-Supported Framework Precision of Fit Evaluation

: In this study, the Periotest instrument was used to measure the precision of fit between cast high noble-metal frameworks and the supporting implants in a patient-simulation model. Three framework conditions and three implant-location variables were used to evaluate the rigidity of the assembly as measured by the Periotest method. The framework variables were (1) one-piece castings (OPC); (2) sectioned-soldered inaccurate castings (SSIC); and (3) sectioned-soldered accurate castings (SSAC). The implant-location variables were right anterior (RA), center (C), and left anterior (LA). Materials and Methods : The patient simulation model used consisted of three self-tapping BrÅnemark implants in a reasonable arch curvature in bovine bone. Three working casts were fabricated from the patient-simulation model using polyvinyl siloxane and tapered impression copings. From the working casts, three sets of three frameworks were fabricated as OPCs, SSICs, and SSACs using type 3 high noble alloy. The SSICs were fabricated with a quantitative misfit of 101.6 Μm at the facial surface, between the abutment-to-gold cylinder interface at the C implant location. Periotest value (PTV) measurements were made at the midfacial surface of the frameworks directly above each abutment-to-gold cylinder interface. Three measurements were made for each test condition. The data were analyzed to compare framework condition(s) and implant location(s) using ANOVA and Fisher's Protected Least Significant Difference Comparison Test. Results : The ANOVA showed that significant differences exist between the mean PTV data for framework condition and for implant location (p < .01). Significant differences were shown between the mean PTV data for the SSAC assemblies and the OPC and SSIC assemblies. The SSICs displayed a more positive (+) mean PTV than the OPCs. The OPC assemblies had a more positive mean PTV than the SSAC assemblies. The mean PTV data for the SSAC assemblies had a significantly different PTV (p < .01) than the other two framework condition assemblies. The OPC and the SSIC assemblies had PTVs that were not significantly different. The C implant location was significantly different from the RA and the LA implant locations (p < .01). The RA and the LA implant locations were not significantly different from each other. The C implant location always demonstrated the most positive mean PTV regardless of the framework condition being tested. Conclusions : The Periotest instrument quantified differences in the precision of fit between three framework conditions. The SSAC assemblies were significantly more rigid than the OPC and SSIC assemblies. The OPC and SSIC assemblies' mean PTVs were not significantly different. The mean PTVs for the C implant location and the RA and LA implant locations were significantly different (p < .01). The mean PTVs of the RA and LA implant locations were not significantly different. The implant-location PTVs followed the same rank order for all three framework conditions. The procedures used to fabricate a more precise fit between the framework and the supporting implants is influenced by the skill of the clinician and technician.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75096/1/j.1532-849X.1996.tb00298.x.pd

Roles of P2 receptors in glial cells: focus on astrocytes

Central nervous system glial cells release and respond to nucleotides under both physiological and pathological conditions, suggesting that these molecules play key roles in both normal brain function and in repair after damage. In particular, ATP released from astrocytes activates P2 receptors on astrocytes and other brain cells, allowing a form of homotypic and heterotypic signalling, which also involves microglia, neurons and oligodendrocytes. Multiple P2X and P2Y receptors are expressed by both astrocytes and microglia; however, these receptors are differentially recruited by nucleotides, depending upon specific pathophysiological conditions, and also mediate the long-term trophic changes of these cells during inflammatory gliosis. In astrocytes, P2-receptor-induced gliosis occurs via activation of the extracellular-regulated kinases (ERK) and protein kinase B/Akt pathways and involves induction of inflammatory and anti-inflammatory genes, cyclins, adhesion and antiapoptotic molecules. While astrocytic P2Y1 and P2Y2,4 are primarily involved in short-term calcium-dependent signalling, multiple P2 receptor subtypes seem to cooperate to astrocytic long-term changes. Conversely, in microglia, exposure to inflammatory and immunological stimuli results in differential functional changes of distinct P2 receptors, suggesting highly specific roles in acquisition of the activated phenotype. We believe that nucleotide-induced activation of astrocytes and microglia may originally start as a defence mechanism to protect neurons from cytotoxic and ischaemic insults; dysregulation of this process in chronic inflammatory diseases eventually results in neuronal cell damage and loss. On this basis, full elucidation of the specific roles of P2 receptors in these cells may help exploit the beneficial neuroprotective features of activated glia while attenuating their harmful properties and thus provide the basis for novel neuroprotective strategies that specifically target the purinergic system

Intravenous apoptotic spleen cell infusion induces a TGF-beta-dependent regulatory T-cell expansion.: Apoptosis and regulatory T cells

International audienceApoptotic leukocytes are endowed with immunomodulatory properties that can be used to enhance hematopoietic engraftment and prevent graft-versus-host disease (GvHD). This apoptotic cell-induced tolerogenic effect is mediated by host macrophages and not recipient dendritic cells or donor phagocytes present in the bone marrow graft as evidenced by selective cell depletion and trafficking experiments. Furthermore, apoptotic cell infusion is associated with TGF-beta-dependent donor CD4+CD25+ T-cell expansion. Such cells have a regulatory phenotype (CD62L(high) and intracellular CTLA-4+), express high levels of forkhead-box transcription factor p3 (Foxp3) mRNA and exert ex vivo suppressive activity through a cell-to-cell contact mechanism. In vivo CD25 depletion after apoptotic cell infusion prevents the apoptotic cell-induced beneficial effects on engraftment and GvHD occurrence. This highlights the role of regulatory T cells in the tolerogenic effect of apoptotic cell infusion. This novel association between apoptosis and regulatory T-cell expansion may also contribute to preventing deleterious autoimmune responses during normal turnover

The cytokine tumor necrosis factor-like weak inducer of apoptosis and its receptor fibroblast growth factor-inducible 14 have a neuroprotective effect in the central nervous system

<p>Abstract</p> <p>Background</p> <p>Cerebral cortical neurons have a high vulnerability to the harmful effects of hypoxia. However, the brain has the ability to detect and accommodate to hypoxic conditions. This phenomenon, known as preconditioning, is a natural adaptive process highly preserved among species whereby exposure to sub-lethal hypoxia promotes the acquisition of tolerance to a subsequent lethal hypoxic injury. The cytokine tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and its receptor fibroblast growth factor-inducible 14 (Fn14) are found in neurons and their expression is induced by exposure to sub-lethal hypoxia. Accordingly, in this work we tested the hypothesis that the interaction between TWEAK and Fn14 induces tolerance to lethal hypoxic and ischemic conditions.</p> <p>Methods</p> <p>Here we used <it>in vitro </it>and <it>in vivo </it>models of hypoxic and ischemic preconditioning, an animal model of transient middle cerebral artery occlusion and mice and neurons genetically deficient in TWEAK, Fn14, or tumor necrosis factor alpha (TNF-α) to investigate whether treatment with recombinant TWEAK or an increase in the expression of endogenous TWEAK renders neurons tolerant to lethal hypoxia. We used enzyme-linked immunosorbent assay to study the effect of TWEAK on the expression of neuronal TNF-α, Western blot analysis to investigate whether the effect of TWEAK was mediated by activation of mitogen-activated protein kinases and immunohistochemical techniques and quantitative real-time polymerase chain reaction analysis to study the effect of TWEAK on apoptotic cell death.</p> <p>Results</p> <p>We found that either treatment with recombinant TWEAK or an increase in the expression of TWEAK and Fn14 induce hypoxic and ischemic tolerance <it>in vivo </it>and <it>in vitro</it>. This protective effect is mediated by neuronal TNF-α and activation of the extracellular signal-regulated kinases 1 and 2 pathway via phosphorylation and inactivation of the B-cell lymphoma 2-associated death promoter protein.</p> <p>Conclusions</p> <p>Our work indicate that the interaction between TWEAK and Fn14 triggers the activation of a cell signaling pathway that results in the induction of tolerance to lethal hypoxia and ischemia. These data indicate that TWEAK may be a potential therapeutic strategy to protect the brain from the devastating effects of an ischemic injury.</p

Secretome of apoptotic peripheral blood cells (APOSEC) confers cytoprotection to cardiomyocytes and inhibits tissue remodelling after acute myocardial infarction: a preclinical study

Heart failure following acute myocardial infarction (AMI) is a major cause of morbidity and mortality. Our previous observation that injection of apoptotic peripheral blood mononuclear cell (PBMC) suspensions was able to restore long-term cardiac function in a rat AMI model prompted us to study the effect of soluble factors derived from apoptotic PBMC on ventricular remodelling after AMI. Cell culture supernatants derived from irradiated apoptotic peripheral blood mononuclear cells (APOSEC) were collected and injected as a single dose intravenously after myocardial infarction in an experimental AMI rat model and in a porcine closed chest reperfused AMI model. Magnetic resonance imaging (MRI) and echocardiography were used to quantitate cardiac function. Analysis of soluble factors present in APOSEC was performed by enzyme-linked immunosorbent assay (ELISA) and activation of signalling cascades in human cardiomyocytes by APOSEC in vitro was studied by immunoblot analysis. Intravenous administration of a single dose of APOSEC resulted in a reduction of scar tissue formation in both AMI models. In the porcine reperfused AMI model, APOSEC led to higher values of ejection fraction (57.0 vs. 40.5%, p < 0.01), a better cardiac output (4.0 vs. 2.4 l/min, p < 0.001) and a reduced extent of infarction size (12.6 vs. 6.9%, p < 0.02) as determined by MRI. Exposure of primary human cardiac myocytes with APOSEC in vitro triggered the activation of pro-survival signalling-cascades (AKT, Erk1/2, CREB, c-Jun), increased anti-apoptotic gene products (Bcl-2, BAG1) and protected them from starvation-induced cell death. Intravenous infusion of culture supernatant of apoptotic PBMC attenuates myocardial remodelling in experimental AMI models. This effect is probably due to the activation of pro-survival signalling cascades in the affected cardiomyocytes

Targeting and killing of glioblastoma with activated T cells armed with bispecific antibodies

Abstract Background Since most glioblastomas express both wild-type EGFR and EGFRvIII as well as HER2/neu, they are excellent targets for activated T cells (ATC) armed with bispecific antibodies (BiAbs) that target EGFR and HER2. Methods ATC were generated from PBMC activated for 14 days with anti-CD3 monoclonal antibody in the presence of interleukin-2 and armed with chemically heteroconjugated anti-CD3×anti-HER2/neu (HER2Bi) and/or anti-CD3×anti-EGFR (EGFRBi). HER2Bi- and/or EGFRBi-armed ATC were examined for in vitro cytotoxicity using MTT and 51Cr-release assays against malignant glioma lines (U87MG, U118MG, and U251MG) and primary glioblastoma lines. Results EGFRBi-armed ATC killed up to 85% of U87, U118, and U251 targets at effector:target ratios (E:T) ranging from 1:1 to 25:1. Engagement of tumor by EGFRBi-armed ATC induced Th1 and Th2 cytokine secretion by armed ATC. HER2Bi-armed ATC exhibited comparable cytotoxicity against U118 and U251, but did not kill HER2-negative U87 cells. HER2Bi- or EGFRBi-armed ATC exhibited 50—80% cytotoxicity against four primary glioblastoma lines as well as a temozolomide (TMZ)-resistant variant of U251. Both CD133– and CD133+ subpopulations were killed by armed ATC. Targeting both HER2Bi and EGFRBi simultaneously showed enhanced efficacy than arming with a single BiAb. Armed ATC maintained effectiveness after irradiation and in the presence of TMZ at a therapeutic concentration and were capable of killing multiple targets. Conclusion High-grade gliomas are suitable for specific targeting by armed ATC. These data, together with additional animal studies, may provide the preclinical support for the use of armed ATC as a valuable addition to current treatment regimens

Intratumoral CRH modulates immuno-escape of ovarian cancer cells through FasL regulation

Although corticotropin-releasing hormone (CRH) and Fas ligand (FasL) have been documented in ovarian carcinoma, a clear association with tumour progression and immuno-escape has not been established. FasL plays an important role in promoting tumour cells' ability to counterattack immune cells. Here, we examined immunohistochemically the expression of CRH, CRHR1, CRHR2 and FasL in 47 human ovarian cancer cases. The ovarian cancer cell lines OvCa3 and A2780 were further used to test the hypothesis that CRH might contribute to the immune privilege of ovarian tumours, by modulating FasL expression on the cancer cells. We found that CRH, CRHR1, CRHR2 and FasL were expressed in 68.1, 70.2, 63.8 and 63.8% of the cases respectively. Positivity for CRH or FasL expression was associated with higher tumour stage. Finally, CRH increased the expression of FasL in OvCa3 and A2780 cells through CRHR1 thereby potentiated their ability to induce apoptosis of activated peripheral blood lymphocytes. Corticotropin-releasing hormone produced by human ovarian cancer might favour survival and progression of the tumour by promoting its immune privilege. These findings support the hypothesis that CRHR1 antagonists could potentially be used against ovarian cancer

The ROS Scavenger, NAC, Regulates Hepatic Vα14iNKT Cells Signaling during Fas mAb-Dependent Fulminant Liver Failure

Uncontrolled systemic activation of the immune system is an early initiating event that leads to development of acute fulminant liver failure (FLF) in mice after treatment with agonistic Fas mAb. In this study, we demonstrate that treatment of mice with N-acetylcysteine (NAC), an ROS scavenger and glutathione (GSH) precursor, almost completely abolished Fas mAb-induced FLF through suppression of Vα14iNKT cell activation, IFN-γ signaling, apoptosis and nitrotyrosine formation in liver. In addition, enrichment of the liver with GSH due to Vα14iNKT cells deficiency, induced an anti-inflammatory response in the liver of Jα18−/− mice that inhibited apoptosis, nitrotyrosine formation, IFN-γ signaling and effector functions. In summary, we propose a novel and previously unrecognized pro-inflammatory and pro-apoptotic role for endogenous ROS in stimulating Th1 signaling in Vα14iNKT cells to promote the development of FLF. Therefore, our study provides critical new insights into how NAC, a ROS scavenger, regulates Th1 signaling in intrahepatic Vα14iNKT cells to impact inflammatory and pathological responses