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 Sevoflurane Promotes Bactericidal Properties of Macrophages through Enhanced Inducible Nitric Oxide Synthase Expression in Male Mice

2019 ◽  
Vol 131 (6) ◽  
pp. 1301-1315 ◽  
Author(s):  
Thomas J. Gerber ◽  
Valérie C. O. Fehr ◽  
Suellen D. S. Oliveira ◽  
Guochang Hu ◽  
Randal Dull ◽  
...  
Keyword(s):  
Early Stage ◽  
No Synthase ◽  
Control Group ◽  
Male Mice ◽  
Proinflammatory Response ◽  
E Coli ◽  
Inducible No Synthase ◽  
Bactericidal Properties

Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Sevoflurane with its antiinflammatory properties has shown to decrease mortality in animal models of sepsis. However, the underlying mechanism of its beneficial effect in this inflammatory scenario remains poorly understood. Macrophages play an important role in the early stage of sepsis as they are tasked with eliminating invading microbes and also attracting other immune cells by the release of proinflammatory cytokines such as interleukin-1β, interleukin-6, and tumor necrosis factor-α. Thus, the authors hypothesized that sevoflurane mitigates the proinflammatory response of macrophages, while maintaining their bactericidal properties. Methods Murine bone marrow–derived macrophages were stimulated in vitro with lipopolysaccharide in the presence and absence of 2% sevoflurane. Expression of cytokines and inducible NO synthase as well as uptake of fluorescently labeled Escherichia coli (E. coli) were measured. The in vivo endotoxemia model consisted of an intraperitoneal lipopolysaccharide injection after anesthesia with either ketamine and xylazine or 4% sevoflurane. Male mice (n = 6 per group) were observed for a total of 20 h. During the last 30 min fluorescently labeled E. coli were intraperitoneally injected. Peritoneal cells were extracted by peritoneal lavage and inducible NO synthase expression as well as E. coli uptake by peritoneal macrophages was determined using flow cytometry. Results In vitro, sevoflurane enhanced lipopolysaccharide-induced inducible NO synthase expression after 8 h by 466% and increased macrophage uptake of fluorescently labeled E. coli by 70% compared with vehicle-treated controls. Inhibiting inducible NO synthase expression pharmacologically abolished this increase in bacteria uptake. In vivo, inducible NO synthase expression was increased by 669% and phagocytosis of E. coli by 49% compared with the control group. Conclusions Sevoflurane enhances phagocytosis of bacteria by lipopolysaccharide-challenged macrophages in vitro and in vivo via an inducible NO synthase–dependent mechanism. Thus, sevoflurane potentiates bactericidal and antiinflammatory host-defense mechanisms in endotoxemia.

scholarly journals Three-Dimensional In Vitro Staphylococcus aureus Abscess Communities Display Antibiotic Tolerance and Protection from Neutrophil Clearance

2020 ◽  
Vol 88 (11) ◽  
Author(s):  
Marloes I. Hofstee ◽  
Martijn Riool ◽  
Igors Terjajevs ◽  
Keith Thompson ◽  
Martin J. Stoddart ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Immune Cells ◽  
Early Stage ◽  
Three Dimensional ◽  
Collagen Gel ◽  
Maximum Size ◽  
Human Neutrophils ◽  
Content Type

ABSTRACT Staphylococcus aureus is a prominent human pathogen in bone and soft-tissue infections. Pathophysiology involves abscess formation, which consists of central staphylococcal abscess communities (SACs), surrounded by a fibrin pseudocapsule and infiltrating immune cells. Protection against the ingress of immune cells such as neutrophils, or tolerance to antibiotics, remains largely unknown for SACs and is limited by the lack of availability of in vitro models. We describe a three-dimensional in vitro model of SACs grown in a human plasma-supplemented collagen gel. The in vitro SACs reached their maximum size by 24 h and elaborated a fibrin pseudocapsule, as confirmed by electron and immunofluorescence microscopy. The in vitro SACs tolerated 100× the MIC of gentamicin alone and in combination with rifampin, while planktonic controls and mechanically dispersed SACs were efficiently killed. To simulate a host response, SACs were exposed to differentiated PLB-985 neutrophil-like (dPLB) cells and to primary human neutrophils at an early stage of SAC formation or after maturation at 24 h. Both cell types were unable to clear mature in vitro SACs, but dPLB cells prevented SAC growth upon early exposure before pseudocapsule maturation. Neutrophil exposure after plasmin pretreatment of the SACs resulted in a significant decrease in the number of bacteria within the SACs. The in vitro SAC model mimics key in vivo features, offers a new tool to study host-pathogen interactions and drug efficacy assessment, and has revealed the functionality of the S. aureus pseudocapsule in protecting the bacteria from host phagocytic responses and antibiotics.

Increased interferon-mediated immunity following in vitro and in vivo Modafinil treatment on peripheral immune cells

2018 ◽  
Vol 81 ◽  
pp. 297-305 ◽  
Author(s):  
Adriano Zager ◽  
Wesley Nogueira Brandão ◽  
Rafael Oliveira Margatho ◽  
Daniel Sanzio Gimenes Cruz ◽  
Jean Pierre Peron ◽  
...  
Keyword(s):  
Immune Cells ◽  
Peripheral Immune Cells

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 Porcine Haemagglutinating Encephalomyelitis Virus Triggers Neural Autophagy Independent of ULK1

2021 ◽  
Author(s):  
Zi Li ◽  
Feng Gao ◽  
Yungang Lan ◽  
Jiyu Guan ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Time Course ◽  
Ectopic Expression ◽  
Neuroblastoma Cells ◽  
Neurological Dysfunction ◽  
Global Public Health ◽  
Complex Interactions ◽  
Encephalomyelitis Virus ◽  
Bona Fide

Uncoordinated 51-like kinase 1 (ULK1) is a well-characterized initiator of canonical autophagy under basal or pathological conditions. Porcine haemagglutinating encephalomyelitis virus (PHEV), a neurotropic betacoronavirus (β-CoV), impairs ULK1 kinase but hijacks autophagy to facilitate viral proliferation. However, the machinery of PHEV-induced autophagy initiation upon ULK1 kinase deficiency remains unclear. Here, the time course of PHEV infection showed a significant accumulation of autophagosomes (APs) in nerve cells in vivo and in vitro. Utilizing the ULK1-knockout neuroblastoma cells, we have identified that ULK1 was not essential for productive AP formation induced by PHEV. In vitro phosphorylation studies discovered that mTORC1-regulated ULK1 activation stalls during PHEV infection, whereas the AP biogenesis was controlled by AMPK-driven BECN1 phosphorylation. A lack of BECN1 is sufficient to block LC3 lipidation and disrupt recruitment of the LC3-ATG14 complex. Moreover, BECN1 acts as a bona fide substrate for ULK1-independent neural autophagy, and ectopic expression of BECN1 somewhat enhances PHEV replication. These findings highlight a novel machinery of non-canonical autophagy independent of ULK1 that bypasses the conserved initiation circuit of AMPK-mTORC1-ULK1, providing new insights into the interplay between neurotropic β-CoV and the host. IMPORTANCE The ongoing COVID-19 pandemic alongside the outbreaks of SARS and MERS pose betacoronavirus (β-CoV) as a global public health challenge. Coronaviruses subvert, haijack, or utilize autophagy to promote proliferation, thus exploring the cross-talk between β-CoV and autophagy of great significance in confronting future β-CoV outbreaks. Porcine haemagglutinating encephalomyelitis virus (PHEV) is a highly neurotropic β-CoV and invades the central nervous system (CNS) in pigs, but understanding of the pathogenesis for PHEV-induced neurological dysfunction yet limited. Here, we discovered a novel regulatory principle of neural autophagy initiation during PHEV infection, where productive autophagosome (AP) biogenesis bypassing the multifaceted regulation of ULK1 kinase. The PHEV-triggered non-canonical autophagy underscores the complex interactions of virus-host, and will help in the development of therapeutic strategies targeting non-canonical autophagy to treat β-CoV disease.

scholarly journals Ulk1 Governs Nerve Growth Factor/TrkA Signaling by Mediating Rab5 GTPase Activation in Porcine Hemagglutinating Encephalomyelitis Virus-Induced Neurodegenerative Disorders

2018 ◽  
Vol 92 (16) ◽  
Author(s):  
Zi Li ◽  
Kui Zhao ◽  
Xiaoling Lv ◽  
Yungang Lan ◽  
Shiyu Hu ◽  
...  
Keyword(s):  
Nervous System ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Neurite Outgrowth ◽  
Progressive Failure ◽  
Neurological Dysfunction ◽  
Long Distance ◽  
Nerve Growth ◽  
Encephalomyelitis Virus ◽  
Porcine Hemagglutinating Encephalomyelitis Virus

ABSTRACT Porcine hemagglutinating encephalomyelitis virus (PHEV) is a highly neurovirulent coronavirus and causes neurological dysfunction in the central nervous system (CNS), but the neuropathological mechanism of PHEV remains poorly understood. We report that Unc51-like kinase 1 (Ulk1/Unc51.1) is a pivotal regulator of PHEV-induced neurological disorders and functions to selectively control the initiation of nerve growth factor (NGF)/TrkA endosome trafficking. We first identified the function of Ulk1 by histopathologic evaluation in a PHEV-infected mouse model in which neuronal loss was accompanied by the suppression of Ulk1 expression. Morphogenesis assessments in the primary cortical neurons revealed that overexpression or mutations of Ulk1 modulated neurite outgrowth, collateral sprouting, and endosomal transport. Likewise, Ulk1 expression was decreased following PHEV infection, suggesting that there was a correlation between the neurodegeneration and functional Ulk1 deficiency. We then showed that Ulk1 forms a multiprotein complex with TrkA and the early endosome marker Rab5 and that Ulk1 defects lead to either blocking of NGF/TrkA endocytosis or premature degradation of pTrkA via constitutive activation of the Rab5 GTPase. Further investigation determined that the ectopic expression of Rab5 mutants induces aberrant endosomal accumulation of activated pTrkA, proving that targeting of Ulk1-TrkA-NGF signaling to the retrograde transport route in the neurodegenerative process that underlies PHEV infection is dependent on Rab5 GTPase activity. Therefore, we described a long-distance signaling mechanism of PHEV-driven deficits in neurons and suggested that such Ulk1 repression may result in limited NGF/TrkA retrograde signaling within activated Rab5 endosomes, explaining the progressive failure of neurite outgrowth and survival. IMPORTANCE Porcine hemagglutinating encephalomyelitis virus (PHEV) is a neurotropic coronavirus and targets neurons in the nervous system for proliferation, frequently leaving behind grievous neurodegeneration. Structural plasticity disorders occur in the axons, dendrites, and dendritic spines of PHEV-infected neurons, and dysfunction of this neural process may contribute to neurologic pathologies, but the mechanisms remain undetermined. Further understanding of the neurological manifestations underlying PHEV infection in the CNS may provide insights into both neurodevelopmental and neurodegenerative diseases that may be conducive to targeted approaches for treatment. The significance of our research is in identifying an Ulk1-related neurodegenerative mechanism, focusing on the regulatory functions of Ulk1 in the transport of long-distance trophic signaling endosomes, thereby explaining the progressive failure of neurite outgrowth and survival associated with PHEV aggression. This is the first report to define a mechanistic link between alterations in signaling from endocytic pathways and the neuropathogenesis of PHEV-induced CNS disease.

Inhibition of Voltage-Gated Hv1 Alleviates LPS-Induced Neuroinflammation via Regulation of Microglial Metabolic Reprogramming

2022 ◽  
Author(s):  
Lingbin Sun ◽  
Xihua Wang ◽  
Shuyuan Guan ◽  
TAO LUO
Keyword(s):  
Cell Death ◽  
Microglial Activation ◽  
Therapeutic Potential ◽  
Aerobic Glycolysis ◽  
Neuronal Cell ◽  
Metabolic Reprogramming ◽  
Proinflammatory Response ◽  
Voltage Gated

Abstract Background Neuroinflammation plays an important role in the onset and advancement of cognitive loss and neurodegenerative disorders. The voltage-gated H channel (Hv1) has been reported to be involved in microglial activation and act as key drivers of neuroinflammation. This study aims at evaluating the mechanism of Hv1 involvement in neuroinflammation and the therapeutic potential of Hv1 inhibitor, 2-guanidinobenzimidazole (2-GBI), in a model of lipopolysaccharide (LPS)-induced neuroinflammation. Methods We investigated the influence of Hv1 inhibitor (2-GBI) on the generation of reactive oxidative species (ROS), metabolic reprogramming, and inflammatory mediators in vitro and examined the therapeutic potential of 2-GBI on microglial activation and hippocampal neuroinflammation in vivo. Novel object recognition and Y-maze were employed to assess cognitive function. Results 2-GBI reduced the LPS-induced proinflammatory response and aerobic glycolysis in microglia. HIF1α overexpression mediated aerobic glycolysis reprogramming alleviated by 2-GBI. We reported that Hv1 inhibitor exerted a protective effect on LPS-induced neuroinflammation through the ROS/HIF1α and PI3K/AKT/HIF1α pathways -mediated aerobic glycolysis. The cell death of PC12 induced by microglia-mediated neuroinflammation was reversed in a transwell co-culture system by 2-GBI. Furthermore, in vivo results suggested that 2-GBI mitigated the neuroinflammatory processes and recognition injury through regulation of microglial metabolic reprogramming. Conclusion 2-GBI protects LPS-induced neuroinflammation, neuronal cell death, and subsequently reverses the hippocampus-dependent cognitive deficits through regulation of microglial metabolic reprogramming. Taken together, these results demonstrate a key role for Hv1 in driving a pro-inflammatory microglia phenotype in neuroinflammation.

scholarly journals Neutrophils and Macrophages Promote Angiogenesis in the Early Stage of Endometriosis in a Mouse Model

Endocrinology ◽  
2006 ◽  
Vol 147 (3) ◽  
pp. 1278-1286 ◽  
Author(s):  
Yiu-Jiuan Lin ◽  
Ming-Derg Lai ◽  
Huan-Yao Lei ◽  
Lih-Yuh C. Wing
Keyword(s):  
Mouse Model ◽  
Blood Vessels ◽  
Immune Cells ◽  
Early Stage ◽  
Treated Group ◽  
Ectopic Tissue ◽  
Ovariectomized Mice ◽  
Inflammatory Protein ◽  
Endothelial Growth Factor

Substantial evidence suggests that inflammatory cytokines, immune cells, and angiogenesis are important for endometriosis. In this study, we investigated the role of the sequential events in the development of endometriosis in a mouse model. Uterine tissue was transplanted into the peritoneum of ovariectomized mice and then supplemented with estrogen or vehicle. On different days after transplantation, cell proliferation, angiogenesis, and infiltrated immune cells in ectopic tissue were examined using immunochemical staining. Many disintegrated blood vessels but no bromodeoxyuridine-positive cells in ectopic tissue were observed in the estrogen-treated group on posttransplantation d 1 and 2. On d 4–7, bromodeoxyuridine-positive cells were detected in the blood vessels of ectopic tissue, indicating that angiogenesis was initiated in this stage. Angiogenesis also occurred in ectopic tissue in the vehicle-treated group. Profound infiltration of neutrophils in ectopic tissue occurred on d 1–4, when the number of neutrophils and levels of macrophage inflammatory protein (MIP)-1α and MIP-2 chemokines in peritoneal fluids also reached their peak. Peritoneal macrophage numbers did not change, but secretions of TNFα, IL-6, MIP-1α, and MIP-2 from macrophages isolated on d 2 were higher than on d 0. In vitro studies showed that peritoneal neutrophils and macrophages secreted vascular endothelial growth factor, which was up-regulated by TNFα and IL-6. Our results suggest that neutrophils and macrophages may promote angiogenesis in the early stage of endometriosis and that chemokines and cytokines amplify the angiogenic signal for the growth of endometriotic tissue.

scholarly journals The PERK/PKR-eIF2α pathway negatively regulates porcine hemagglutinating encephalomyelitis virus replication by attenuating global protein translation and facilitating stress granule formation

2021 ◽  
Author(s):  
Junchao Shi ◽  
Zi Li ◽  
Rongyi Xu ◽  
Jing Zhang ◽  
Qianyu Zhou ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Severe Acute Respiratory Syndrome ◽  
Protein Translation ◽  
Stress Granule ◽  
Innate Response ◽  
Encephalomyelitis Virus ◽  
Infected Cells ◽  
Porcine Hemagglutinating Encephalomyelitis Virus

The replication of coronaviruses, including severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV) and the recently emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is closely associated with the endoplasmic reticulum (ER) of infected cells. The unfolded protein response (UPR), which is mediated by ER stress (ERS), is a typical outcome in coronavirus-infected cells and is closely associated with the characteristics of coronaviruses. However, the interaction between virus-induced ERS and coronavirus replication is poorly understood. Here, we demonstrated that infection with the betacoronavirus porcine hemagglutinating encephalomyelitis virus (PHEV) induced ERS and triggered all three branches of the UPR signaling pathway both in vitro and in vivo. In addition, ERS suppressed PHEV replication in mouse neuro-2a (N2a) cells primarily by activating the protein kinase R-like ER kinase (PERK)-eukaryotic initiation factor 2α (eIF2α) axis of the UPR. Moreover, another eIF2α phosphorylation kinase, IFN-induced double-stranded RNA-dependent protein kinase (PKR), was also activated and acted cooperatively with PERK to decrease PHEV replication. Furthermore, we demonstrated that the PERK/PKR-eIF2α pathways negatively regulated PHEV replication by attenuating global protein translation. Phosphorylated eIF2α also promoted the formation of stress granule (SG), which in turn repressed PHEV replication. In summary, our study presents a vital aspect of the host innate response to invading pathogens and reveals attractive host targets (e.g., PERK, PKR and eIF2α) for antiviral drugs. IMPORTANCE Coronavirus diseases are caused by different coronaviruses of importance in humans and animals, and specific treatments are extremely limited. ERS, which can activate the UPR to modulate viral replication and the host innate response, is a frequent occurrence in coronavirus-infected cells. PHEV, a neurotropic β-coronavirus, causes nerve cell damage, which accounts for the high mortality rates in suckling piglets. However, it remains incompletely understood whether the highly developed ER in nerve cells plays an antiviral role in ERS and how ERS regulates viral proliferation. In this study, we found that PHEV infection induced ERS and activated the UPR both in vitro and in vivo and that the activated PERK/PKR-eIF2α axis inhibited PHEV replication through attenuating global protein translation and promoting SG formation. A better understanding of coronavirus-induced ERS and UPR activation may reveal the pathogenic mechanism of coronavirus and facilitate the development of new treatment strategies for these diseases.

Sign in / Sign up

Export Citation Format

Share Document