scholarly journals Neuroinvasion and Encephalitis Following Intranasal Inoculation of SARS-CoV-2 in K18-hACE2 Mice

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 132 ◽  
Author(s):  
Pratima Kumari ◽  
Hussin A. Rothan ◽  
Janhavi P. Natekar ◽  
Shannon Stone ◽  
Heather Pathak ◽  
...  
Keyword(s):  
Neurological Disease ◽  
Infectious Virus ◽  
Severe Disease ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Intranasal Infection ◽  
Cytokines And Chemokines ◽  
The Central Nervous System ◽  
The Brain ◽  
Very High

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection can cause neurological disease in humans, but little is known about the pathogenesis of SARS-CoV-2 infection in the central nervous system (CNS). Herein, using K18-hACE2 mice, we demonstrate that SARS-CoV-2 neuroinvasion and encephalitis is associated with mortality in these mice. Intranasal infection of K18-hACE2 mice with 105 plaque-forming units of SARS-CoV-2 resulted in 100% mortality by day 6 after infection. The highest virus titers in the lungs were observed on day 3 and declined on days 5 and 6 after infection. By contrast, very high levels of infectious virus were uniformly detected in the brains of all the animals on days 5 and 6. Onset of severe disease in infected mice correlated with peak viral levels in the brain. SARS-CoV-2-infected mice exhibited encephalitis hallmarks characterized by production of cytokines and chemokines, leukocyte infiltration, hemorrhage and neuronal cell death. SARS-CoV-2 was also found to productively infect cells within the nasal turbinate, eye and olfactory bulb, suggesting SARS-CoV-2 entry into the brain by this route after intranasal infection. Our data indicate that direct infection of CNS cells together with the induced inflammatory response in the brain resulted in the severe disease observed in SARS-CoV-2-infected K18-hACE2 mice.

scholarly journals Neuroinvasion and encephalitis following intranasal inoculation of SARS-CoV-2 in K18-hACE2 mice

2020 ◽  
Author(s):  
Pratima Kumari ◽  
Hussin A. Rothan ◽  
Janhavi P. Natekar ◽  
Shannon Stone ◽  
Heather Pathak ◽  
...  
Keyword(s):  
Neurological Disease ◽  
Infectious Virus ◽  
Severe Disease ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Intranasal Infection ◽  
Cytokines And Chemokines ◽  
The Central Nervous System ◽  
The Brain ◽  
Very High

AbstractSevere acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection can cause neurological disease in humans, but little is known about the pathogenesis of SARS-CoV-2 infection in the central nervous system. Herein, using K18-hACE2 mice, we demonstrate that SARS-CoV-2 neuroinvasion and encephalitis is associated with mortality in these mice. Intranasal infection of K18-hACE2 mice with 105 plaque-forming units of SARS-CoV-2 resulted in 100% mortality by day 6 after infection. The highest virus titers in the lungs were observed at day 3 and declined at days 5 and 6 after infection. In contrast, very high levels of infectious virus were uniformly detected in the brains of all the animals at days 5 and 6. Onset of severe disease in infected mice correlated with peak viral levels in the brain. SARS-CoV-2-infected mice exhibited encephalitis hallmarks characterized by production of cytokines and chemokines, leukocyte infiltration, hemorrhage and neuronal cell death. SARS-CoV-2 was also found to productively infect cells within the nasal turbinate, eye and olfactory bulb, suggesting SARS-CoV-2 entry into the brain by this route after intranasal infection. Our data indicate that direct infection of CNS cells together with the induced inflammatory response in the brain resulted in the severe disease observed in SARS-CoV-2-infected K18-hACE2 mice.

scholarly journals Neuronal Cell Death Mechanisms in Major Neurodegenerative Diseases

2018 ◽  
Vol 19 (10) ◽  
pp. 3082 ◽  
Author(s):  
Hao Chi ◽  
Hui-Yun Chang ◽  
Tzu-Kang Sang
Keyword(s):  
Cell Death ◽  
Neurodegenerative Diseases ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Alpha Synuclein ◽  
Adult Brain ◽  
Pathological Feature ◽  
The Central Nervous System ◽  
Cell Death Mechanisms ◽  
The Brain

Neuronal cell death in the central nervous system has always been a challenging process to decipher. In normal physiological conditions, neuronal cell death is restricted in the adult brain, even in aged individuals. However, in the pathological conditions of various neurodegenerative diseases, cell death and shrinkage in a specific region of the brain represent a fundamental pathological feature across different neurodegenerative diseases. In this review, we will briefly go through the general pathways of cell death and describe evidence for cell death in the context of individual common neurodegenerative diseases, discussing our current understanding of cell death by connecting with renowned pathogenic proteins, including Tau, amyloid-beta, alpha-synuclein, huntingtin and TDP-43.

Brain Protection by Erythropoietin: A Manifold Task

Physiology ◽  
2008 ◽  
Vol 23 (5) ◽  
pp. 263-274 ◽  
Author(s):  
Tamer Rabie ◽  
Hugo H. Marti
Keyword(s):  
Central Nervous System ◽  
Cell Death ◽  
Nervous System ◽  
Dominant Role ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Brain Protection ◽  
Hematopoietic Growth Factors ◽  
The Central Nervous System ◽  
The Brain

Many hematopoietic growth factors are produced locally in the brain. Among these, erythropoietin (Epo), has a dominant role for neuroprotection, neurogenesis, and acting as a neurotrophic factor in the central nervous system. These functions make erythropoietin a good candidate for treating diseases associated with neuronal cell death.

scholarly journals TLR-Mediated Signal Transduction and Neurodegenerative Disorders

2021 ◽  
Vol 11 (11) ◽  
pp. 1373
Author(s):  
Shashank Vishwanath Adhikarla ◽  
Niraj Kumar Jha ◽  
Vineet Kumar Goswami ◽  
Ankur Sharma ◽  
Anuradha Bhardwaj ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Immune System ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Adaptive Immune System ◽  
Human Beings ◽  
Toll Like Receptors ◽  
Cytokines And Chemokines ◽  
The Central Nervous System

A special class of proteins called Toll-like receptors (TLRs) are an essential part of the innate immune system, connecting it to the adaptive immune system. There are 10 different Toll-Like Receptors that have been identified in human beings. TLRs are part of the central nervous system (CNS), showing that the CNS is capable of the immune response, breaking the long-held belief of the brain’s “immune privilege” owing to the blood–brain barrier (BBB). These Toll-Like Receptors are present not just on the resident macrophages of the central nervous system but are also expressed by the neurons to allow them for the production of proinflammatory agents such as interferons, cytokines, and chemokines; the activation and recruitment of glial cells; and their participation in neuronal cell death by apoptosis. This study is focused on the potential roles of various TLRs in various neurodegenerative diseases such as Parkinson’s disease (PD) and Alzheimer’s disease (AD), namely TLR2, TLR3, TLR4, TLR7, and TLR9 in AD and PD in human beings and a mouse model.

scholarly journals Induction of the Nrf2 Pathway by Sulforaphane Is Neuroprotective in a Rat Temporal Lobe Epilepsy Model

Antioxidants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1702
Author(s):  
Sereen Sandouka ◽  
Tawfeeq Shekh-Ahmad
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Status Epilepticus ◽  
Temporal Lobe Epilepsy ◽  
Antioxidant Capacity ◽  
Temporal Lobe ◽  
Epileptiform Activity ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
The Brain

Epilepsy is a chronic disease of the brain that affects over 65 million people worldwide. Acquired epilepsy is initiated by neurological insults, such as status epilepticus, which can result in the generation of ROS and induction of oxidative stress. Suppressing oxidative stress by upregulation of the transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2) has been shown to be an effective strategy to increase endogenous antioxidant defences, including in brain diseases, and can ameliorate neuronal damage and seizure occurrence in epilepsy. Here, we aim to test the neuroprotective potential of a naturally occurring Nrf2 activator sulforaphane, in in vitro epileptiform activity model and a temporal lobe epilepsy rat model. Sulforaphane significantly decreased ROS generation during epileptiform activity, restored glutathione levels, and prevented seizure-like activity-induced neuronal cell death. When given to rats after 2 h of kainic acid-induced status epilepticus, sulforaphane significantly increased the expression of Nrf2 and related antioxidant genes, improved oxidative stress markers, and increased the total antioxidant capacity in both the plasma and hippocampus. In addition, sulforaphane significantly decreased status epilepticus-induced neuronal cell death. Our results demonstrate that Nrf2 activation following an insult to the brain exerts a neuroprotective effect by reducing neuronal death, increasing the antioxidant capacity, and thus may also modify epilepsy development.

scholarly journals Peroxiredoxin 5 Inhibits Glutamate-Induced Neuronal Cell Death through the Regulation of Calcineurin-Dependent Mitochondrial Dynamics in HT22 Cells

2019 ◽  
Vol 39 (20) ◽  
Author(s):  
Mi Hye Kim ◽  
Hong Jun Lee ◽  
Sang-Rae Lee ◽  
Hyun-Shik Lee ◽  
Jae-Won Huh ◽  
...  
Keyword(s):  
Cell Death ◽  
Neurodegenerative Diseases ◽  
Mitochondrial Dynamics ◽  
Mitochondrial Fission ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Glutamate Toxicity ◽  
Ht22 Cells ◽  
Peroxidase Enzyme ◽  
The Central Nervous System

ABSTRACT Glutamate is an essential neurotransmitter in the central nervous system (CNS). However, high glutamate concentrations can lead to neurodegenerative diseases. A hallmark of glutamate toxicity is high levels of reactive oxygen species (ROS), which can trigger Ca2+ influx and dynamin-related protein 1 (Drp1)-mediated mitochondrial fission. Peroxiredoxin 5 (Prx5) is a well-known cysteine-dependent peroxidase enzyme. However, the precise effects of Prx5 on glutamate toxicity are still unclear. In this study, we investigated the role of Prx5 in glutamate-induced neuronal cell death. We found that glutamate treatment induces endogenous Prx5 expression and Ca2+/calcineurin-dependent dephosphorylation of Drp1, resulting in mitochondrial fission and neuronal cell death. Our results indicate that Prx5 inhibits glutamate-induced mitochondrial fission through the regulation of Ca2+/calcineurin-dependent dephosphorylation of Drp1, and it does so by scavenging cytosolic and mitochondrial ROS. Therefore, we suggest that Ca2+/calcineurin-dependent mitochondrial dynamics are deeply associated with glutamate-induced neurotoxicity. Consequently, Prx5 may be used as a potential agent for developing therapies against glutamate-induced neurotoxicity and neurodegenerative diseases where it plays a key role.

scholarly journals Pharmacologic Depletion of Microglia Increases Viral Load in the Brain and Enhances Mortality in Murine Models of Flavivirus-Induced Encephalitis

2018 ◽  
Vol 92 (16) ◽  
Author(s):  
Scott Seitz ◽  
Penny Clarke ◽  
Kenneth L. Tyler
Keyword(s):  
Immune Cells ◽  
Mrna Level ◽  
Cns Injury ◽  
Cytokines And Chemokines ◽  
Life Threatening ◽  
The Central Nervous System ◽  
The Brain ◽  
Stimulating Factor ◽  
Life Threatening Event

ABSTRACT Flaviviruses account for most arthropod-borne cases of human encephalitis in the world. However, the exact mechanisms of injury to the central nervous system (CNS) during flavivirus infections remain poorly understood. Microglia are the resident immune cells of the CNS and are important for multiple functions, including control of viral pathogenesis. Utilizing a pharmacologic method of microglia depletion (PLX5622 [Plexxikon Inc.], an inhibitor of colony-stimulating factor 1 receptor), we sought to determine the role of microglia in flaviviral pathogenesis. Depletion of microglia resulted in increased mortality and viral titer in the brain following infection with either West Nile virus (WNV) or Japanese encephalitis virus (JEV). Interestingly, microglial depletion did not prevent virus-induced increases in the expression of relevant cytokines and chemokines at the mRNA level. In fact, the expression of several proinflammatory genes was increased in virus-infected, microglia-depleted mice compared to virus-infected, untreated controls. In contrast, and as expected, expression of the macrophage marker triggering receptor expressed on myeloid cells 2 (TREM2) was decreased in virus-infected, PLX5622-treated mice compared to virus-infected controls. IMPORTANCE As CNS invasion by flaviviruses is a rare but life-threatening event, it is critical to understand how brain-resident immune cells elicit protection or injury during disease progression. Microglia have been shown to be important in viral clearance but may also contribute to CNS injury as part of the neuroinflammatory process. By utilizing a microglial depletion model, we can begin to parse out the exact roles of microglia during flaviviral pathogenesis with hopes of understanding specific mechanisms as potential targets for therapeutics.

scholarly journals Peroxiredoxin II Maintains the Mitochondrial Membrane Potential against Alcohol-Induced Apoptosis in HT22 Cells

Antioxidants ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Mei-Hua Jin ◽  
Jia-Bin Yu ◽  
Hu-Nan Sun ◽  
Ying-Hua Jin ◽  
Gui-Nan Shen ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Ht22 Cells ◽  
Apoptotic Protein ◽  
Intracellular Ros ◽  
Induced Apoptosis ◽  
The Brain

Excessive alcohol intake can significantly reduce cognitive function and cause irreversible learning and memory disorders. The brain is particularly vulnerable to alcohol-induced ROS damage; the hippocampus is one of the most sensitive areas of the brain for alcohol neurotoxicity. In the present study, we observed significant increasing of intracellular ROS accumulations in Peroxiredoxin II (Prx II) knockdown HT22 cells, which were induced by alcohol treatments. We also found that the level of ROS in mitochondrial was also increased, resulting in a decrease in the mitochondrial membrane potential. The phosphorylation of GSK3β (Ser9) and anti-apoptotic protein Bcl2 expression levels were significantly downregulated in Prx II knockdown HT22 cells, which suggests that Prx II knockdown HT22 cells were more susceptible to alcohol-induced apoptosis. Scavenging the alcohol-induced ROS with NAC significantly decreased the intracellular ROS levels, as well as the phosphorylation level of GSK3β in Prx II knockdown HT22 cells. Moreover, NAC treatment also dramatically restored the mitochondrial membrane potential and the cellular apoptosis in Prx II knockdown HT22 cells. Our findings suggest that Prx II plays a crucial role in alcohol-induced neuronal cell apoptosis by regulating the cellular ROS levels, especially through regulating the ROS-dependent mitochondrial membrane potential. Consequently, Prx II may be a therapeutic target molecule for alcohol-induced neuronal cell death, which is closely related to ROS-dependent mitochondria dysfunction.

scholarly journals Neuroprotective Effect of Antioxidants in the Brain

2020 ◽  
Vol 21 (19) ◽  
pp. 7152 ◽  
Author(s):  
Kyung Hee Lee ◽  
Myeounghoon Cha ◽  
Bae Hwan Lee
Keyword(s):  
Oxidative Stress ◽  
Neurodegenerative Diseases ◽  
Intracellular Signaling ◽  
Neuronal Damage ◽  
Neuroprotective Effect ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
High Energy ◽  
Antioxidant Compounds ◽  
The Brain

The brain is vulnerable to excessive oxidative insults because of its abundant lipid content, high energy requirements, and weak antioxidant capacity. Reactive oxygen species (ROS) increase susceptibility to neuronal damage and functional deficits, via oxidative changes in the brain in neurodegenerative diseases. Overabundance and abnormal levels of ROS and/or overload of metals are regulated by cellular defense mechanisms, intracellular signaling, and physiological functions of antioxidants in the brain. Single and/or complex antioxidant compounds targeting oxidative stress, redox metals, and neuronal cell death have been evaluated in multiple preclinical and clinical trials as a complementary therapeutic strategy for combating oxidative stress associated with neurodegenerative diseases. Herein, we present a general analysis and overview of various antioxidants and suggest potential courses of antioxidant treatments for the neuroprotection of the brain from oxidative injury. This review focuses on enzymatic and non-enzymatic antioxidant mechanisms in the brain and examines the relative advantages and methodological concerns when assessing antioxidant compounds for the treatment of neurodegenerative disorders.

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.

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