scholarly journals UNC93B1 Is Widely Expressed in the Murine CNS and Is Required for Neuroinflammation and Neuronal Injury Induced by MicroRNA let-7b

2021 ◽  
Vol 12 ◽  
Author(s):  
Markus G. Klammer ◽  
Omar Dzaye ◽  
Thomas Wallach ◽  
Christina Krüger ◽  
Dorothea Gaessler ◽  
...  
Keyword(s):  
Microglial Activation ◽  
Neuronal Injury ◽  
Wild Type ◽  
Tlr Signaling ◽  
Chaperone Protein ◽  
The Central Nervous System ◽  
Murine Brain ◽  
Functional Relevance ◽  
Peripheral Immune Cells

The chaperone protein Unc-93 homolog B1 (UNC93B1) regulates internalization, trafficking, and stabilization of nucleic acid-sensing Toll-like receptors (TLR) in peripheral immune cells. We sought to determine UNC93B1 expression and its functional relevance in inflammatory and injurious processes in the central nervous system (CNS). We found that UNC93B1 is expressed in various CNS cells including microglia, astrocytes, oligodendrocytes, and neurons, as assessed by PCR, immunocyto-/histochemistry, and flow cytometry. UNC93B1 expression in the murine brain increased during development. Exposure to the microRNA let-7b, a recently discovered endogenous TLR7 activator, but also to TLR3 and TLR4 agonists, led to increased UNC93B1 expression in microglia and neurons. Microglial activation by extracellular let-7b required functional UNC93B1, as assessed by TNF ELISA. Neuronal injury induced by extracellular let-7b was dependent on UNC93B1, as UNC93B1-deficient neurons were unaffected by the microRNA’s neurotoxicity in vitro. Intrathecal application of let-7b triggered neurodegeneration in wild-type mice, whereas mice deficient for UNC93B1 were protected against injurious effects on neurons and axons. In summary, our data demonstrate broad UNC93B1 expression in the murine brain and establish this chaperone as a modulator of neuroinflammation and neuronal injury triggered by extracellular microRNA and subsequent induction of TLR signaling.

scholarly journals Paeoniflorin Attenuates Inflammatory Pain by Inhibiting Microglial Activation and Akt-NF-κB Signaling in the Central Nervous System

2018 ◽  
Vol 47 (2) ◽  
pp. 842-850 ◽  
Author(s):  
Bo Hu ◽  
Guangtao Xu ◽  
Xiaomin Zhang ◽  
Long Xu ◽  
Hong Zhou ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Signaling Pathway ◽  
Inflammatory Pain ◽  
Microglial Activation ◽  
Enzyme Linked Immunosorbent Assay ◽  
Pain Model ◽  
The Central Nervous System

Background/Aims: Paeoniflorin (PF) is known to have anti-inflammatory and paregoric effects, but the mechanism underlying its analgesic effect remains unclear. The aim of this study was to clarify the effect of PF on Freund’s complete adjuvant (CFA)-induced inflammatory pain and explore the underlying molecular mechanism. Methods: An inflammatory pain model was established by intraplantar injection of CFA in C57BL/6J mice. After intrathecal injection of PF daily for 8 consecutive days, thermal and mechanical withdrawal thresholds, the levels of inflammatory factors TNF-α, IL-1β and IL-6, microglial activity, and the expression of Akt-NF-κB signaling pathway in the spinal cord tissue were detected by animal ethological test, cell culture, enzyme-linked immunosorbent assay, immunofluorescence histochemistry, and western blot. Results: PF inhibited the spinal microglial activation in the CFA-induced pain model. The production of proinflammatory cytokines was decreased in the central nervous system after PF treatment both in vivo and in vitro. PF further displayed a remarkable effect on inhibiting the activation of Akt-NF-κB signaling pathway in vivo and in vitro. Conclusion: These results suggest that PF is a potential therapeutic agent for inflammatory pain and merits further investigation.

scholarly journals Apolipoprotein E Deficiency Aggravates Neuronal Injury by Enhancing Neuroinflammation via the JNK/c-Jun Pathway in the Early Phase of Experimental Subarachnoid Hemorrhage in Mice

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Yue Wu ◽  
Jinwei Pang ◽  
Jianhua Peng ◽  
Fang Cao ◽  
Zongduo Guo ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Inflammatory Response ◽  
Neuronal Apoptosis ◽  
Microglial Activation ◽  
Axonal Injury ◽  
Neuronal Injury ◽  
Neurological Deficits ◽  
Immunofluorescent Staining

Neuronal injury is the primary cause of poor outcome after subarachnoid hemorrhage (SAH). The apolipoprotein E (APOE) gene has been suggested to be involved in the prognosis of SAH patients. However, the role of APOE in neuronal injury after SAH has not been well studied. In this study, SAH was induced in APOE-knockout (APOE-/-) and wild-type (WT) mice to investigate the impact of APOE deficiency on neuronal injury in the early phase of SAH. The experiments of this study were performed in murine SAH models in vivo and primary cultured microglia and neurons in vitro. The SAH model was induced by endovascular perforation in APOE-/- and APOE WT mice. The mortality rate, weight loss, and neurological deficits were recorded within 72 h after SAH. The neuronal injury was assessed by detecting the neuronal apoptosis and axonal injury. The activation of microglia was assessed by immunofluorescent staining of Iba-1, and clodronate liposomes were used for inhibiting microglial activation. The expression of JNK/c-Jun was evaluated by immunofluorescent staining or western blotting. The expression of TNF-α, IL-1β, and IL-6 was evaluated by ELISA. Primary cultured microglia were treated with hemoglobin (Hb) in vitro for simulating the pathological process of SAH. SP600125, a JNK inhibitor, was used for evaluating the role of JNK in neuroinflammation. Nitrite production was detected for microglial activation, and flow cytometry was performed to detect apoptosis in vitro. The results suggested that SAH induced early neuronal injury and neurological deficits in mice. APOE deficiency resulted in more severe neurological deficits after SAH in mice. The neurological deficits were associated with exacerbation of neuronal injury, including neuronal apoptosis and axonal injury. Moreover, APOE deficiency enhanced microglial activation and related inflammatory injury on neurons. Inhibition of microglia attenuated neuronal injury in mice, whereas inhibition of JNK inhibited microglia-mediated inflammatory response in vitro. Taken together, JNK/c-Jun was involved in the enhancement of microglia-mediated inflammatory injury in APOE-/- mice. APOE deficiency aggravates neuronal injury which may account for the poor neurological outcomes of APOE-/- mice. The possible protective role of APOE against EBI via the modulation of inflammatory response indicates its potential treatment for SAH.

The atypical chemokine receptor CCX-CKR scavenges homeostatic chemokines in circulation and tissues and suppresses Th17 responses

Blood ◽  
2010 ◽  
Vol 116 (20) ◽  
pp. 4130-4140 ◽  
Author(s):  
Iain Comerford ◽  
Robert J. B. Nibbs ◽  
Wendel Litchfield ◽  
Mark Bunting ◽  
Yuka Harata-Lee ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
Lymph Nodes ◽  
Chemokine Receptor ◽  
Fold Increase ◽  
Wild Type ◽  
Peripheral Lymph ◽  
The Central Nervous System

Abstract Our previous in vitro studies led to proposals that the atypical chemokine receptor CCX-CKR is a scavenger of CCR7 ligand homeostatic chemokines. In the present study, we generated CCX-CKR−/− mice and confirm this scavenger function in vivo. Compared with wild-type mice, CCX-CKR−/− have a 5-fold increase in the level of CCL21 protein in blood, and 2- to 3-fold increases in CCL19 and CCL21 in peripheral lymph nodes. The effect of these protein increases on immunity was investigated after immunization with MOG35-55 peptide emulsified in complete Freund adjuvant (CFA). The subsequent characteristic paralysis develops with enhanced kinetics and severity in CCX-CKR−/− versus wild-type mice. Despite this effect, antigen-specific immune responses in the draining lymph nodes are diminished in CCX-CKR−/− mice. Instead, the earlier onset of disease is associated with enhanced T-cell priming in the CCX-CKR−/− spleen and a skewing of CD4+ T-cell responses toward Th17 rather than Th1. This observation correlates with increased expression of IL-23 in the CCX-CKR−/− spleen and increased CCL21 levels in the central nervous system postimmunization. The early onset of disease in CCX-CKR−/− mice is reversed by systemic administration of neutralizing anti-CCL21 antibodies. Thus, by regulating homeostatic chemokine bioavailability, CCX-CKR influences the localization, kinetics, and nature of adaptive immune responses in vivo.

scholarly journals Roles of the TRAF6 and Pellino E3 ligases in MyD88 and RANKL signaling

2017 ◽  
Vol 114 (17) ◽  
pp. E3481-E3489 ◽  
Author(s):  
Sam Strickson ◽  
Christoph H. Emmerich ◽  
Eddy T. H. Goh ◽  
Jiazhen Zhang ◽  
Ian R. Kelsall ◽  
...  
Keyword(s):  
Bone Structure ◽  
Late Phase ◽  
E3 Ligase ◽  
Wild Type ◽  
Tlr Signaling ◽  
E3 Ligases ◽  
Phase Production

It is widely accepted that the essential role of TRAF6 in vivo is to generate the Lys63-linked ubiquitin (K63-Ub) chains needed to activate the “master” protein kinase TAK1. Here, we report that TRAF6 E3 ligase activity contributes to but is not essential for the IL-1–dependent formation of K63-Ub chains, TAK1 activation, or IL-8 production in human cells, because Pellino1 and Pellino2 generate the K63-Ub chains required for signaling in cells expressing E3 ligase-inactive TRAF6 mutants. The IL-1–induced formation of K63-Ub chains and ubiquitylation of IRAK1, IRAK4, and MyD88 was abolished in TRAF6/Pellino1/Pellino2 triple-knockout (KO) cells, but not in TRAF6 KO or Pellino1/2 double-KO cells. The reexpression of E3 ligase-inactive TRAF6 mutants partially restored IL-1 signaling in TRAF6 KO cells, but not in TRAF6/Pellino1/Pellino2 triple-KO cells. Pellino1-generated K63-Ub chains activated the TAK1 complex in vitro with similar efficiently to TRAF6-generated K63-Ub chains. The early phase of TLR signaling and the TLR-dependent secretion of IL-10 (controlled by IRAKs 1 and 2) was only reduced modestly in primary macrophages from knockin mice expressing the E3 ligase-inactive TRAF6[L74H] mutant, but the late-phase production of IL-6, IL-12, and TNFα (controlled only by the pseudokinase IRAK2) was abolished. RANKL-induced signaling in macrophages and the differentiation of bone marrow to osteoclasts was similar in TRAF6[L74H] and wild-type cells, explaining why the bone structure and teeth of the TRAF6[L74H] mice was normal, unlike TRAF6 KO mice. We identify two essential roles of TRAF6 that are independent of its E3 ligase activity.

scholarly journals DJ-1 inhibits microglial activation and protects dopaminergic neurons in vitro and in vivo through interacting with microglial p65

2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Zixuan Lin ◽  
Chen Chen ◽  
Dongqin Yang ◽  
Jianqing Ding ◽  
Guanghui Wang ◽  
...  
Keyword(s):  
Microglial Activation ◽  
Nuclear Translocation ◽  
Substantia Nigra Pars Compacta ◽  
Loss Of Function ◽  
Wild Type ◽  
Wild Type Littermate ◽  
Cellular Models ◽  
Bv2 Cells

AbstractParkinson’s disease (PD), one of the most common neurodegenerative disorders, is characterized by progressive neurodegeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). DJ-1 acts essential roles in neuronal protection and anti-neuroinflammatory response, and its loss of function is tightly associated with a familial recessive form of PD. However, the molecular mechanism of DJ-1 involved in neuroinflammation is largely unclear. Here, we found that wild-type DJ-1, rather than the pathogenic L166P mutant DJ-1, directly binds to the subunit p65 of nuclear factor-κB (NF-κB) in the cytoplasm, and loss of DJ-1 promotes p65 nuclear translocation by facilitating the dissociation between p65 and NF-κB inhibitor α (IκBα). DJ-1 knockout (DJ-1−/−) mice exhibit more microglial activation compared with wild-type littermate controls, especially in response to lipopolysaccharide (LPS) treatment. In cellular models, knockdown of DJ-1 significantly upregulates the gene expression and increases the release of LPS-treated inflammatory cytokines in primary microglia and BV2 cells. Furthermore, DJ-1 deficiency in microglia significantly enhances the neuronal toxicity in response to LPS stimulus. In addition, pharmacological blockage of NF-κB nuclear translocation by SN-50 prevents microglial activation and alleviates the damage of DA neurons induced by microglial DJ-1 deficiency in vivo and in vitro. Thus, our data illustrate a novel mechanism by which DJ-1 facilitates the interaction between IκBα and p65 by binding to p65 in microglia, and thus repressing microglial activation and exhibiting the protection of DA neurons from neuroinflammation-mediated injury in PD.

Activation of microglia reveals a non-proteolytic cytokine function for tissue plasminogen activator in the central nervous system

1999 ◽  
Vol 112 (22) ◽  
pp. 4007-4016 ◽  
Author(s):  
A.D. Rogove ◽  
C. Siao ◽  
B. Keyt ◽  
S. Strickland ◽  
S.E. Tsirka
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Microglial Activation ◽  
Neuronal Degeneration ◽  
Wild Type ◽  
Tissue Plasminogen ◽  
Cortical Cultures ◽  
The Central Nervous System

Tissue plasminogen activator mediates excitotoxin-induced neurodegeneration and microglial activation in the mouse hippocampus. Here we show that tissue plasminogen activator (tPA) acts in a protease-independent manner to modulate the activation of microglia, the cells of the central nervous system with macrophage properties. Cultured microglia from tPA-deficient mice can phagocytose as efficiently as wild-type microglia. However, tPA-deficient microglia in mixed cortical cultures exhibit attenuated activation in response to lipopolysaccharide, as judged by morphological changes, increased expression of the activation marker F4/80 and the release of the pro-inflammatory cytokine tumor necrosis factor-(α). When tPA is added to tPA deficient cortical cultures prior to endotoxin stimulation, microglial activation is restored to levels comparable to that observed in wild-type cells. Proteolytically-inactive tPA can also restore activation of tPA-deficient microglia in culture and in vivo. However, this inactive enzyme does not restore susceptibility of tPA-deficient hippocampal neurons to excitotoxin-mediated cell death. These results dissociate two different functions of tPA: inactive enzyme can mediate microglial activation, whereas proteolytically-competent protein also promotes neuronal degeneration. Thus tPA is identified as a new cytokine in the central nervous system.

scholarly journals Local Overexpression of Interleukin-11 in the Central Nervous System Limits Demyelination and Enhances Remyelination

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Anurag Maheshwari ◽  
Kris Janssens ◽  
Jeroen Bogie ◽  
Chris Van Den Haute ◽  
Tom Struys ◽  
...  
Keyword(s):  
Microglial Activation ◽  
Clinical Symptoms ◽  
Demyelinating Diseases ◽  
Blue Staining ◽  
Autoimmune Encephalomyelitis ◽  
Microscopy Imaging ◽  
The Central Nervous System ◽  
Interleukin 11 ◽  
Experimental Autoimmune

Demyelination is one of the pathological hallmarks of multiple sclerosis (MS). To date, no therapy is available which directly potentiates endogenous remyelination. Interleukin-11 (IL-11), a member of the gp130 family of cytokines, is upregulated in MS lesions. Systemic IL-11 treatment was shown to ameliorate clinical symptoms in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. IL-11 modulates immune cells and protects oligodendrocytesin vitro. In this study, the cuprizone-induced demyelination mouse model was used to elucidate effects of IL-11 on de- and remyelination, independent of the immune response. Prophylactic-lentiviral- (LV-) mediated overexpression of IL-11 in mouse brain significantly limited acute demyelination, which was accompanied with the preservation of CC1+mature oligodendrocytes (OLs) and a decrease in microglial activation (Mac-2+). We further demonstrated that IL-11 directly reduces myelin phagocytosisin vitro. When IL-11 expressing LV was therapeutically applied in animals with extensive demyelination, a significant enhancement of remyelination was observed as demonstrated by Luxol Fast Blue staining and electron microscopy imaging. Our results indicate that IL-11 promotes maturation of NG2+OPCs into myelinating CC1+OLs and may thus explain the enhanced remyelination. Overall, we demonstrate that IL-11 is of therapeutic interest for MS and other demyelinating diseases by limiting demyelination and promoting remyelination.

scholarly journals Evidence of Microglial Immune Response Following Coronavirus PHEV Infection of CNS

2022 ◽  
Vol 12 ◽  
Author(s):  
Jing Zhang ◽  
Zi Li ◽  
Huijun Lu ◽  
Junchao Shi ◽  
Rui Gao ◽  
...  
Keyword(s):  
Immune Cells ◽  
Microglial Activation ◽  
Early Stage ◽  
Neurological Dysfunction ◽  
Proinflammatory Response ◽  
Peripheral Monocyte ◽  
Encephalomyelitis Virus ◽  
Peripheral Immune Cells ◽  
Porcine Hemagglutinating Encephalomyelitis Virus

Porcine hemagglutinating encephalomyelitis virus (PHEV) is a highly neurotropic coronavirus that invades the host central nervous system (CNS) and causes neurological dysfunction. Microglia are key immune cells in the CNS, however, whether and how they response to PHEV infection remains unclear. Herein, microglial activation and proliferation were detected in the CNS of PHEV-infected mice, as along with the proinflammatory response. Moreover, the production of proinflammatory cytokines induced by moderately activated microglia limited viral replication in the early stage of infection. Microglial depletion assays showed that during late infection, excess activation of microglia aggravated neurological symptoms, BBB destruction, and peripheral monocyte/macrophage infiltration into the CNS. Using an in vitro brain slice model, PHEV was identified to specifically and moderately induce microglial activation in the absence of peripheral immune cells infiltration. Consistently, macrophage clearance from circulating blood indicated that peripheral monocytes/macrophages crossing the BBB of mice were responsible for excess activation of microglia and CNS damage in late PHEV infection. Overall, our findings provide evidence supporting a dual role for microglia in the host CNS in response to coronavirus PHEV invasion.

scholarly journals PTP1B inhibitor alleviates deleterious microglial activation and neuronal injury after ischemic stroke by modulating ER stress-autophagy axis via PERK signaling in microglia

2019 ◽  
Author(s):  
Yu Zhu ◽  
Jianbo Yu ◽  
Jiangbiao Gong ◽  
Di Ye ◽  
Dexin Cheng ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Er Stress ◽  
Protein Interaction ◽  
Neuronal Apoptosis ◽  
Microglial Activation ◽  
Neuronal Injury ◽  
Primary Microglia ◽  
Cerebral Ir Injury

Abstract Background : Cerebral ischemia/reperfusion (IR) after ischemic stroke causes microglial activation which lead to neuronal injury. Protein tyrosine phosphatase 1B (PTP1B) emerges to be a positive regulator of neuroinflammation, yet the effect of its inhibition on microglial activation as well as cerebral IR injury is largely unknown. Here we explored whether PTP1B inhibitor sc-222227 attenuates microglial activation and mitigates neuronal injury after cerebral IR injury. Methods : Cerebral IR injury rat model was induced by transient middle cerebral artery occlusion (MCAO) and reperfusion. PTP1B inhibitor sc-222227 was administered intracerebroventricularly 0.5 h before IR injury. Neurological deficits, infarct volume and brain water content were examined. In vitro IR injury model were established by oxygen glucose deprivation/reoxygenation (OGD/R) in rat primary microglia. PTP1B protein level, microglial activation, neuroinflammation, endoplasmic reticulum (ER) stress, autophagy and neuronal apoptosis were detected in vivo and/or in vitro using western blot, immunohistochemistry, immunofluorescence, ELISA and real-time PCR assay. Protein interaction were assessed by proximity ligation assay. Results : PTP1B expression were significantly increased after cerebral IR injury in vivo, and the enhancement was most prominent in microglia. PTP1B inhibitor reduced IR-induced microglial activation both in vitro and in vivo, and further attenuated IR-induced microglial ER stress and autophagy in rat. In vitro experiment showed PTP1B inhibitor mitigated OGD/R-induced microglial activation through inhibiting ER stress-dependent autophagy, whose effect was partly abolished by PERK activator CCT020312. The protein interaction between PTP1B and phosphorylated PERK were significantly increase in response to OGD/R in primary microglia. Finally, PTP1B inhibitor reduced neuronal apoptosis and improved neurologic function after cerebral IR injury in rat. Conclusions : PTP1B inhibitor ameliorated neuronal injury and neurologic deficits following cerebral IR injury via attenuating deleterious microglial activation and subsequent neuroinflammation through modulating ER stress-autophagy axis in microglia. Treatment targeting microglial PTP1B might be a potential therapeutic strategy for ischemic stroke treatment.

scholarly journals Delta Opioid Receptor Agonists Ameliorate Colonic Inflammation by Modulating Immune Responses

2021 ◽  
Vol 12 ◽  
Author(s):  
Kazuki Nagata ◽  
Hiroshi Nagase ◽  
Ayumi Okuzumi ◽  
Chiharu Nishiyama
Keyword(s):  
Opioid Receptor ◽  
Opioid Receptors ◽  
Immune Cells ◽  
Inflammatory Cytokine ◽  
Mesenteric Lymph Nodes ◽  
The Central Nervous System ◽  
Pass Through ◽  
Δ Opioid Receptor ◽  
Peripheral Immune Cells

The opioid receptors play important roles in the regulation of sense and emotions. Although it is recently revealed that opioid receptors are also expressed in various cells, but not restricted in the central nervous system, the effects of opioids on peripheral immune cells are largely unknown. In the current study, we evaluated the effect of opioids on immune system by using selective agonists for δ opioid receptor. Systemic administration of KNT-127 or intraperitoneal injection of YNT-2715 (a KNT-127-related compound that cannot pass through the blood-brain barrier) significantly alleviated the pathology of dextran sodium sulfate-induced colitis. In KNT-127-treated mice, the levels of an inflammatory cytokine IL-6 in the serum, and macrophages in the mesenteric lymph nodes (MLNs) were decreased in the progression stage, and those of regulatory T cells (Tregs) in the MLN were increased in the recovery stage. In vitro experiments revealed that KNT-127 inhibited the release of IL-6 and another inflammatory cytokine TNF-α from macrophages and accelerated the development of Tregs. Our study suggests that δ opioid agonists act directly on immune cells to improve the pathology of the colitis and can be candidates of immunomodulatory drugs.

Sign in / Sign up

Export Citation Format

Share Document