scholarly journals Environmental stimuli shape microglial plasticity in glioma

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Stefano Garofalo ◽  
Alessandra Porzia ◽  
Fabrizio Mainiero ◽  
Silvia Di Angelantonio ◽  
Barbara Cortese ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nk Cells ◽  
Myeloid Cells ◽  
Environmental Cues ◽  
Inflammatory Gene Expression ◽  
Cytokines And Chemokines ◽  
Interleukin 15 ◽  
Modulation Of Gene Expression ◽  
Ifn Γ ◽  
The Brain

In glioma, microglia and infiltrating macrophages are exposed to factors that force them to produce cytokines and chemokines, which contribute to tumor growth and to maintaining a pro-tumorigenic, immunosuppressed microenvironment. We demonstrate that housing glioma-bearing mice in enriched environment (EE) reverts the immunosuppressive phenotype of infiltrating myeloid cells, by modulating inflammatory gene expression. Under these conditions, the branching and patrolling activity of myeloid cells is increased, and their phagocytic activity is promoted. Modulation of gene expression depends on interferon-(IFN)-γ produced by natural killer (NK) cells. This modulation disappears in mice depleted of NK cells or lacking IFN-γ, and was mimicked by exogenous interleukin-15 (IL-15). Further, we describe a key role for brain-derived neurotrophic factor (BDNF) that is produced in the brain of mice housed in EE, in mediating the expression of IL-15 in CD11b+ cells. These data define novel mechanisms linking environmental cues to the acquisition of a pro-inflammatory, anti-tumor microenvironment in mouse brain.

P151 DISRUPTION OF ENDOGENOUS ITACONATE PRODUCTION EXACERBATES EXPERIMENTAL COLITIS

2020 ◽  
Vol 26 (Supplement_1) ◽  
pp. S5-S6
Author(s):  
Ryan Frieler ◽  
Thomas Vigil ◽  
Richard Mortensen ◽  
Yatrik Shah
Keyword(s):  
Gene Expression ◽  
Immune Cell ◽  
Tricarboxylic Acid Cycle ◽  
Myeloid Cells ◽  
Experimental Colitis ◽  
Cell Types ◽  
Cell Phenotype ◽  
Inflammatory Gene Expression ◽  
Inflammatory Gene ◽  
Anti Inflammatory

Abstract Background Inflammation is a hallmark of inflammatory bowel disease and alterations in tricarboxylic acid cycle (TCA) metabolism have been identified as major regulators of immune cell phenotype during inflammation and hypoxia. The TCA cycle metabolite, itaconate, is produced by the enzyme aconitate decarboxylase 1 (Acod1) and is highly upregulated during classical macrophage activation and during experimental colitis. Itaconate and cell permeable derivatives have robust anti-inflammatory effects on macrophages, therefore we hypothesized that Acod1-produced itaconate has a protective, anti-inflammatory effect during experimental colitis. Methods and Results Wild type (WT) control and Acod1-/- mice were administered 3% Dextran Sulfate Sodium (DSS) in water for 7 days to induce experimental colitis. After DSS was discontinued, Acod1-/- mice had significantly reduced body weight recovery with increased macroscopic disease severity, and upon dissection had decreased colon length and more severe inflammation. To determine if myeloid cells are the critical Acod1/itaconate-producing cell types, we generated myeloid-specific Acod1 deficient mice, however no differences in weight loss, colon length or inflammatory gene expression were detected compared to WT controls. To test whether supplementation with exogenous itaconate could ameliorate colitis, WT mice were treated with the cell-permeable form of itaconate, dimethyl itaconate (DMI). Administration of DMI significantly improved recovery after 7 days of DSS treatment and significantly reduced inflammatory gene expression in the colon. Conclusion Our data suggest that Acod1-produced itaconate has an important role in the regulation of inflammation during experimental colitis. Although myeloid cells have been thought to be major producers of Acod1 and itaconate, our data indicate that other cell types are involved. These results highlight the importance of this immunometabolic pathway and suggest that preservation or enhancement of this pathway with natural metabolites or metabolite derivatives could have beneficial effects during colitis.

scholarly journals Viral Infection of the Central Nervous System and Neuroinflammation Precede Blood-Brain Barrier Disruption during Japanese Encephalitis Virus Infection

2015 ◽  
Vol 89 (10) ◽  
pp. 5602-5614 ◽  
Author(s):  
Fang Li ◽  
Yueyun Wang ◽  
Lan Yu ◽  
Shengbo Cao ◽  
Ke Wang ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Japanese Encephalitis Virus ◽  
Inflammatory Cytokines ◽  
Japanese Encephalitis ◽  
Cytokines And Chemokines ◽  
The Central Nervous System ◽  
Ifn Γ ◽  
Bbb Permeability ◽  
The Brain

ABSTRACTJapanese encephalitis is an acute zoonotic, mosquito-borne disease caused by Japanese encephalitis virus (JEV). Japanese encephalitis is characterized by extensive inflammation in the central nervous system (CNS) and disruption of the blood-brain barrier (BBB). However, the pathogenic mechanisms contributing to the BBB disruption are not known. Here, using a mouse model of intravenous JEV infection, we show that virus titers increased exponentially in the brain from 2 to 5 days postinfection. This was accompanied by an early, dramatic increase in the level of inflammatory cytokines and chemokines in the brain. Enhancement of BBB permeability, however, was not observed until day 4, suggesting that viral entry and the onset of inflammation in the CNS occurred prior to BBB damage.In vitrostudies revealed that direct infection with JEV could not induce changes in the permeability of brain microvascular endothelial cell monolayers. However, brain extracts derived from symptomatic JEV-infected mice, but not from mock-infected mice, induced significant permeability of the endothelial monolayer. Consistent with a role for inflammatory mediators in BBB disruption, the administration of gamma interferon-neutralizing antibody ameliorated the enhancement of BBB permeability in JEV-infected mice. Taken together, our data suggest that JEV enters the CNS, propagates in neurons, and induces the production of inflammatory cytokines and chemokines, which result in the disruption of the BBB.IMPORTANCEJapanese encephalitis (JE) is the leading cause of viral encephalitis in Asia, resulting in 70,000 cases each year, in which approximately 20 to 30% of cases are fatal, and a high proportion of patients survive with serious neurological and psychiatric sequelae. Pathologically, JEV infection causes an acute encephalopathy accompanied by BBB dysfunction; however, the mechanism is not clear. Thus, understanding the mechanisms of BBB disruption in JEV infection is important. Our data demonstrate that JEV gains entry into the CNS prior to BBB disruption. Furthermore, it is not JEV infectionper se, but the inflammatory cytokines/chemokines induced by JEV infection that inhibit the expression of TJ proteins and ultimately result in the enhancement of BBB permeability. Neutralization of gamma interferon (IFN-γ) ameliorated the enhancement of BBB permeability in JEV-infected mice, suggesting that IFN-γ could be a potential therapeutic target. This study would lead to identification of potential therapeutic avenues for the treatment of JEV infection.

scholarly journals Regulation of human NK-cell cytokine and chemokine production by target cell recognition

Blood ◽  
2010 ◽  
Vol 115 (11) ◽  
pp. 2167-2176 ◽  
Author(s):  
Cyril Fauriat ◽  
Eric O. Long ◽  
Hans-Gustaf Ljunggren ◽  
Yenan T. Bryceson
Keyword(s):  
Nk Cells ◽  
Target Cell ◽  
Cell Activation ◽  
Nk Cell ◽  
Cell Recognition ◽  
Chemokine Production ◽  
Relative Contribution ◽  
Cytokines And Chemokines ◽  
Tnf Α ◽  
Ifn Γ

AbstractNatural killer (NK)–cell recognition of infected or neoplastic cells can induce cytotoxicity and cytokine secretion. So far, it has been difficult to assess the relative contribution of multiple NK-cell activation receptors to cytokine and chemokine production upon target cell recognition. Using Drosophila cells expressing ligands for the NK-cell receptors LFA-1, NKG2D, DNAM-1, 2B4, and CD16, we studied the minimal requirements for secretion by freshly isolated, human NK cells. Target cell stimulation induced secretion of predominately proinflammatory cytokines and chemokines. Release of chemokines MIP-1α, MIP-1β, and RANTES was induced within 1 hour of stimulation, whereas release of TNF-α and IFN-γ occurred later. Engagement of CD16, 2B4, or NKG2D sufficed for chemokine release, whereas induction of TNF-α and IFN-γ required engagement of additional receptors. Remarkably, our results revealed that, upon target cell recognition, CD56dim NK cells were more prominent cytokine and chemokine producers than CD56bright NK cells. The present data demonstrate how specific target cell ligands dictate qualitative and temporal aspects of NK-cell cytokine and chemokine responses. Conceptually, the results point to CD56dim NK cells as an important source of cytokines and chemokines upon recognition of aberrant cells, producing graded responses depending on the multiplicity of activating receptors engaged.

scholarly journals The effects of n-6 polyunsaturated fatty acid deprivation on the inflammatory gene response to lipopolysaccharide in the mouse hippocampus

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Shoug M. Alashmali ◽  
Lin Lin ◽  
Marc-Olivier Trépanier ◽  
Giulia Cisbani ◽  
Richard P. Bazinet
Keyword(s):  
Gene Expression ◽  
Fatty Acids ◽  
Diet Group ◽  
Inflammatory Gene Expression ◽  
Inflammatory Gene ◽  
Left Lateral Ventricle ◽  
Gene Response ◽  
Mouse Hippocampus ◽  
Total Fatty Acids ◽  
The Brain

Abstract Background Neuroinflammation is thought to contribute to psychiatric and neurological disorders such as major depression and Alzheimer’s disease (AD). N-6 polyunsaturated fatty acids (PUFA) and molecules derived from them, including linoleic acid- and arachidonic acid-derived lipid mediators, are known to have pro-inflammatory properties in the periphery; however, this has yet to be tested in the brain. Lowering the consumption of n-6 PUFA is associated with a decreased risk of depression and AD in human observational studies. The purpose of this study was to investigate the inflammation-modulating effects of lowering dietary n-6 PUFA in the mouse hippocampus. Methods C57BL/6 male mice were fed either an n-6 PUFA deprived (2% of total fatty acids) or an n-6 PUFA adequate (23% of total fatty acids) diet from weaning to 12 weeks of age. Animals then underwent intracerebroventricular surgery, in which lipopolysaccharide (LPS) was injected into the left lateral ventricle of the brain. Hippocampi were collected at baseline and following LPS administration (1, 3, 7, and 14 days). A microarray (n = 3 per group) was used to identify candidate genes and results were validated by real-time PCR in a separate cohort of animals (n = 5–8 per group). Results Mice administered with LPS had significantly increased Gene Ontology categories associated with inflammation and immune responses. These effects were independent of changes in gene expression in any diet group. Results were validated for the effect of LPS treatment on astrocyte, cytokine, and chemokine markers, as well as some results of the diets on Ifrd2 and Mfsd2a expression. Conclusions LPS administration increases pro-inflammatory and lipid-metabolizing gene expression in the mouse hippocampus. An n-6 PUFA deprived diet modulated inflammatory gene expression by both increasing and decreasing inflammatory gene expression, without impairing the resolution of neuroinflammation following LPS administration.

scholarly journals Differential Regulation of Interferon Regulatory Factor (IRF)-7 and IRF-9 Gene Expression in the Central Nervous System during Viral Infection

2005 ◽  
Vol 79 (12) ◽  
pp. 7514-7527 ◽  
Author(s):  
Shalina S. Ousman ◽  
Jianping Wang ◽  
Iain L. Campbell
Keyword(s):  
Gene Expression ◽  
Central Nervous System ◽  
Nervous System ◽  
Viral Infection ◽  
Mononuclear Cells ◽  
Lymphocytic Choriomeningitis ◽  
The Central Nervous System ◽  
Ifn Γ ◽  
The Brain ◽  
Lcmv Infection

ABSTRACT Interferon regulatory factors (IRFs) are a family of transcription factors involved in the regulation of the interferons (IFNs) and other genes that may have an essential role in antiviral defense in the central nervous system, although this is currently not well defined. Therefore, we examined the regulation of IRF gene expression in the brain during viral infection. Several IRF genes (IRF-2, -3, -5, -7, and -9) were expressed at low levels in the brain of uninfected mice. Following intracranial infection with lymphocytic choriomeningitis virus (LCMV), expression of the IRF-7 and IRF-9 genes increased significantly by day 2. IRF-7 and IRF-9 gene expression in the brain was widespread at sites of LCMV infection, with the highest levels in infiltrating mononuclear cells, microglia/macrophages, and neurons. IRF-7 and IRF-9 gene expression was increased in LCMV-infected brain from IFN-γ knockout (KO) but not IFN-α/βR KO animals. In the brain, spleen, and liver or cultured glial and spleen cells, IRF-7 but not IRF-9 gene expression increased with delayed kinetics in the absence of STAT1 but not STAT2 following LCMV infection or IFN-α treatment, respectively. The stimulation of IRF-7 gene expression by IFN-α in glial cell culture was prevented by cycloheximide. Thus, (i) many of the IRF genes were expressed constitutively in the mouse brain; (ii) the IRF-7 and IRF-9 genes were upregulated during viral infection, a process dependent on IFN-α/β but not IFN-γ; and (iii) IRF-7 but not IRF-9 gene expression can be stimulated in a STAT1-independent but STAT2-dependent fashion via unidentified indirect pathways coupled to the activation of the IFN-α/β receptor.

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