scholarly journals Microglia do not restrict SARS-CoV-2 replication following infection of the central nervous system of K18-hACE2 transgenic mice

2021 ◽  
Author(s):  
Gema M. Olivarria ◽  
Yuting Cheng ◽  
Susana Furman ◽  
Collin Pachow ◽  
Lindsay A. Hohsfield ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Transgenic Mice ◽  
Viral Replication ◽  
Host Defense ◽  
Lung Pathology ◽  
Neurologic Disease ◽  
Viral Pathogen ◽  
Neurologic Symptoms ◽  
The Central Nervous System

Unlike SARS-CoV-1 and MERS-CoV, infection with SARS-CoV-2, the viral pathogen responsible for COVID-19, is often associated with neurologic symptoms that range from mild to severe, yet increasing evidence argues the virus does not exhibit extensive neuroinvasive properties. We demonstrate SARS-CoV-2 can infect and replicate in human iPSC-derived neurons and that infection shows limited anti-viral and inflammatory responses but increased activation of EIF2 signaling following infection as determined by RNA sequencing. Intranasal infection of K18 human ACE2 transgenic mice (K18-hACE2) with SARS-CoV-2 resulted in lung pathology associated with viral replication and immune cell infiltration. In addition, ∼50% of infected mice exhibited CNS infection characterized by wide-spread viral replication in neurons accompanied by increased expression of chemokine ( Cxcl9, Cxcl10, Ccl2, Ccl5 and Ccl19 ) and cytokine ( Ifn-λ and Tnf-α ) transcripts associated with microgliosis and a neuroinflammatory response consisting primarily of monocytes/macrophages. Microglia depletion via administration of colony-stimulating factor 1 receptor inhibitor, PLX5622, in SARS-CoV-2 infected mice did not affect survival or viral replication but did result in dampened expression of proinflammatory cytokine/chemokine transcripts and a reduction in monocyte/macrophage infiltration. These results argue that microglia are dispensable in terms of controlling SARS-CoV-2 replication in in the K18-hACE2 model but do contribute to an inflammatory response through expression of pro-inflammatory genes. Collectively, these findings contribute to previous work demonstrating the ability of SARS-CoV-2 to infect neurons as well as emphasizing the potential use of the K18-hACE2 model to study immunological and neuropathological aspects related to SARS-CoV-2-induced neurologic disease. Importance Understanding the immunological mechanisms contributing to both host defense and disease following viral infection of the CNS is of critical importance given the increasing number of viruses that are capable of infecting and replicating within the nervous system. With this in mind, the present study was undertaken to evaluate the role of microglia in aiding in host defense following experimental infection of the central nervous system (CNS) of K18-hACE2 with SARS-CoV-2, the causative agent of COVID-19. Neurologic symptoms that range in severity are common in COVID-19 patients and understanding immune responses that contribute to restricting neurologic disease can provide important insight into better understanding consequences associated with SARS-CoV-2 infection of the CNS.

scholarly journals Microglia do not restrict SARS-CoV-2 replication following infection of the central nervous system of K18-hACE2 transgenic mice

2021 ◽  
Author(s):  
Gema M Olivarria ◽  
Yuting Cheng ◽  
Collin Pachow ◽  
Lindsay A Hohsfield ◽  
Charlene Smith-Geater ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Viral Replication ◽  
Immune Cell ◽  
Inflammatory Responses ◽  
Cns Infection ◽  
Lung Pathology ◽  
Viral Pathogen ◽  
Tnf Α ◽  
The Central Nervous System ◽  
Human Ipsc

Unlike SARS-CoV-1 and MERS-CoV, infection with SARS-CoV-2, the viral pathogen responsible for COVID-19, is often associated with neurologic symptoms that range from mild to severe, yet increasing evidence argues the virus does not exhibit extensive neuroinvasive properties. We demonstrate SARS-CoV-2 can infect and replicate in human iPSC-derived neurons and that infection shows limited anti-viral and inflammatory responses but increased activation of EIF2 signaling following infection as determined by RNA sequencing. Intranasal infection of K18 human ACE2 transgenic mice (K18-hACE2) with SARS-CoV-2 resulted in lung pathology associated with viral replication and immune cell infiltration. In addition, ~50% of infected mice exhibited CNS infection characterized by wide-spread viral replication in neurons accompanied by increased expression of chemokine (Cxcl9, Cxcl10, Ccl2, Ccl5 and Ccl19) and cytokine (Ifn-λ and Tnf-α) transcripts associated with microgliosis and a neuroinflammatory response consisting primarily of monocytes/macrophages. Microglia depletion via administration of colony-stimulating factor 1 receptor inhibitor, PLX5622, in SARS-CoV-2 infected mice did not affect survival or viral replication but did result in dampened expression of proinflammatory cytokine/chemokine transcripts and a reduction in monocyte/macrophage infiltration. These results argue that microglia are dispensable in terms of controlling SARS-CoV-2 replication in in the K18-hACE2 model but do contribute to an inflammatory response through expression of pro-inflammatory genes. Collectively, these findings contribute to previous work demonstrating the ability of SARS-CoV-2 to infect neurons as well as emphasizing the potential use of the K18-hACE2 model to study immunological and neuropathological aspects related to SARS-CoV-2-induced neurologic disease.

scholarly journals The microbiota protects from viral-induced neurologic damage through microglia-intrinsic TLR signaling

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
D Garrett Brown ◽  
Raymond Soto ◽  
Soumya Yandamuri ◽  
Colleen Stone ◽  
Laura Dickey ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Oral Administration ◽  
Viral Replication ◽  
Viral Infection ◽  
Host Defense ◽  
Toll Like Receptor ◽  
Tlr Signaling ◽  
The Central Nervous System ◽  
The Brain

Symbiotic microbes impact the function and development of the central nervous system (CNS); however, little is known about the contribution of the microbiota during viral-induced neurologic damage. We identify that commensals aid in host defense following infection with a neurotropic virus through enhancing microglia function. Germfree mice or animals that receive antibiotics are unable to control viral replication within the brain leading to increased paralysis. Microglia derived from germfree or antibiotic-treated animals cannot stimulate viral-specific immunity and microglia depletion leads to worsened demyelination. Oral administration of toll-like receptor (TLR) ligands to virally infected germfree mice limits neurologic damage. Homeostatic activation of microglia is dependent on intrinsic signaling through TLR4, as disruption of TLR4 within microglia, but not the entire CNS (excluding microglia), leads to increased viral-induced clinical disease. This work demonstrates that gut immune-stimulatory products can influence microglia function to prevent CNS damage following viral infection.

Degeneration of skeletal muscle, peripheral nerves, and the central nervous system in transgenic mice overexpressing wild-type prion proteins

Cell ◽  
1994 ◽  
Vol 76 (1) ◽  
pp. 117-129 ◽  
Author(s):  
David Westaway ◽  
Stephen J. DeArmond ◽  
Juliana Cayetano-Canlas ◽  
Darlene Groth ◽  
Dallas Foster ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Central Nervous System ◽  
Nervous System ◽  
Transgenic Mice ◽  
Peripheral Nerves ◽  
Prion Proteins ◽  
Wild Type ◽  
The Central Nervous System

scholarly journals Borna Disease Virus Accelerates Inflammation and Disease Associated with Transgenic Expression of Interleukin-12 in the Central Nervous System

2002 ◽  
Vol 76 (23) ◽  
pp. 12223-12232 ◽  
Author(s):  
Susanna Freude ◽  
Jürgen Hausmann ◽  
Markus Hofer ◽  
Ngan Pham-Mitchell ◽  
Iain L. Campbell ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Transgenic Mice ◽  
Disease Virus ◽  
Biologically Active ◽  
Interleukin 12 ◽  
Wild Type ◽  
Borna Disease Virus ◽  
The Central Nervous System ◽  
Borna Disease

ABSTRACT Targeted expression of biologically active interleukin-12 (IL-12) in astrocytes of the central nervous system (CNS) results in spontaneous neuroimmunological disease of aged mice. Borna disease virus (BDV) can readily multiply in the mouse CNS but does not trigger disease in most strains. Here we show that a large percentage of IL-12 transgenic mice developed severe ataxia within 5 to 10 weeks after infection with BDV. By contrast, no disease developed in mock-infected IL-12 transgenic and wild-type mice until 4 months of age. Neurological symptoms were rare in infected wild-type animals, and if they occurred, these were milder and appeared later. Histological analyses showed that the cerebellum of infected IL-12 transgenic mice, which is the brain region with strongest transgene expression, contained large numbers of CD4+ and CD8+ T cells as well as lower numbers of B cells, whereas other parts of the CNS showed only mild infiltration by lymphocytes. The cerebellum of diseased mice further showed severe astrogliosis, calcifications and signs of neurodegeneration. BDV antigen and nucleic acids were present in lower amounts in the inflamed cerebellum of infected transgenic mice than in the noninflamed cerebellum of infected wild-type littermates, suggesting that IL-12 or IL-12-induced cytokines exhibited antiviral activity. We propose that BDV infection accelerates the frequency by which immune cells such as lymphocytes and NK cells enter the CNS and then respond to IL-12 present in the local milieu causing disease. Our results illustrate that infection of the CNS with a virus that is benign in certain hosts can be harmful in such normally disease-resistant hosts if the tissue is unfavorably preconditioned by proinflammatory cytokines.

Infestations expérimentales de crabes juvéniles par la sacculine. Ultrastructure des racines parasitaires en croissance et relations avec la niasse ganglionnaire ventrale de l'hôte

1981 ◽  
Vol 59 (9) ◽  
pp. 1818-1826 ◽  
Author(s):  
Geneviève G. Payen ◽  
Michelle Hubert ◽  
Yves Turquier ◽  
Claudio Rubiliani ◽  
Colette Chassard-Bouchaud
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Connective Tissue ◽  
Host Defense ◽  
Root Cells ◽  
Sacculina Carcini ◽  
The Central Nervous System ◽  
The One ◽  
Host Tissues

Experimental infestations of young Carcinus with Sacculina carcini indicate that the ventral ganglionic mass (VGM) is the first "target" of the parasite roots into the host tissues. As in pubescent crabs naturally parasitized, either with or without an external visceral sac, the roots penetrate and invade that area of the central nervous system during the first month of infestation.Ultrastructural study of the developing roots, in contact with the VGM, leads to the conclusion that apart from a few embryonic characters, the root cells show a cytostructure similar to the one that has been observed in the roots naturally parasitizing pubescent crabs, whether the external visceral sac is present or not.In the two cases of infestation the roots which cross the neurolemma bring about a marked disorganization of ganglia in consequence of the alteration of the neuroglia, neuropiles and neurosecretory areas.An action of the parasite at a distance, i.e. in the absence of contact of the roots with the ganglia, also occurs. It is especially marked as early as 1 month after infestation by a degeneration of the secretory perikarya.A thin sheath of connective tissue is sometimes visible between the growing roots and the VGM of juvenile crabs. However, the existence of that tissue cannot be definitely attributed to a host defense reaction.No effect of the developing parasite on the already differentiated external sex characters of the host has been noticed within the limits of the experiments.

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