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1.
J Virol ; 95(19): e0085121, 2021 09 09.
Article in English | MEDLINE | ID: covidwho-1403028

ABSTRACT

Uncoordinated 51-like kinase 1 (ULK1) is a well-characterized initiator of canonical autophagy under basal or pathological conditions. Porcine hemagglutinating encephalomyelitis virus (PHEV), a neurotropic betacoronavirus (ß-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 ULK1-knockout neuroblastoma cells, we have identified that ULK1 is not essential for productive AP formation induced by PHEV. In vitro phosphorylation studies discovered that mTORC1-regulated ULK1 activation stalls during PHEV infection, whereas 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 noncanonical autophagy independent of ULK1 that bypasses the conserved initiation circuit of AMPK-mTORC1-ULK1, providing new insights into the interplay between neurotropic ß-CoV and the host. IMPORTANCE The ongoing coronavirus disease 2019 (COVID-19) pandemic alongside the outbreaks of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) pose Betacoronavirus (ß-CoV) as a global public health challenge. Coronaviruses subvert, hijack, or utilize autophagy to promote proliferation, and thus, exploring the cross talk between ß-CoV and autophagy is of great significance in confronting future ß-CoV outbreaks. Porcine hemagglutinating encephalomyelitis virus (PHEV) is a highly neurotropic ß-CoV that invades the central nervous system (CNS) in pigs, but understanding of the pathogenesis for PHEV-induced neurological dysfunction is yet limited. Here, we discovered a novel regulatory principle of neural autophagy initiation during PHEV infection, where productive autophagosome (AP) biogenesis bypasses the multifaceted regulation of ULK1 kinase. The PHEV-triggered noncanonical autophagy underscores the complex interactions of virus and host and will help in the development of therapeutic strategies targeting noncanonical autophagy to treat ß-CoV disease.


Subject(s)
Autophagy-Related Protein-1 Homolog/genetics , Autophagy-Related Protein-1 Homolog/metabolism , Autophagy/physiology , Betacoronavirus 1/metabolism , Animals , Autophagosomes/metabolism , Beclin-1/metabolism , COVID-19 , Cell Line , Gene Knockout Techniques , Intracellular Signaling Peptides and Proteins/metabolism , Male , Mechanistic Target of Rapamycin Complex 1/metabolism , Mice , Mice, Inbred BALB C , Neurons/metabolism , Phosphorylation , SARS-CoV-2
2.
J Neuroinflammation ; 18(1): 167, 2021 Jul 29.
Article in English | MEDLINE | ID: covidwho-1331945

ABSTRACT

BACKGROUND: Neurological complications are common in patients affected by COVID-19 due to the ability of SARS-CoV-2 to infect brains. While the mechanisms of this process are not fully understood, it has been proposed that SARS-CoV-2 can infect the cells of the neurovascular unit (NVU), which form the blood-brain barrier (BBB). The aim of the current study was to analyze the expression pattern of the main SARS-CoV-2 receptors in naïve and HIV-1-infected cells of the NVU in order to elucidate a possible pathway of the virus entry into the brain and a potential modulatory impact of HIV-1 in this process. METHODS: The gene and protein expression profile of ACE2, TMPRSS2, ADAM17, BSG, DPP4, AGTR2, ANPEP, cathepsin B, and cathepsin L was assessed by qPCR, immunoblotting, and immunostaining, respectively. In addition, we investigated if brain endothelial cells can be affected by the exposure to the S1 subunit of the S protein, the domain responsible for the direct binding of SARS-CoV-2 to the ACE2 receptors. RESULTS: The receptors involved in SARS-CoV-2 infection are co-expressed in the cells of the NVU, especially in astrocytes and microglial cells. These receptors are functionally active as exposure of endothelial cells to the SARS CoV-2 S1 protein subunit altered the expression pattern of tight junction proteins, such as claudin-5 and ZO-1. Additionally, HIV-1 infection upregulated ACE2 and TMPRSS2 expression in brain astrocytes and microglia cells. CONCLUSIONS: These findings provide key insight into SARS-CoV-2 recognition by cells of the NVU and may help to develop possible treatment of CNS complications of COVID-19.


Subject(s)
Blood Vessels/metabolism , COVID-19/complications , HIV Infections/metabolism , HIV-1 , Neurons/metabolism , Receptors, Virus/genetics , Receptors, Virus/metabolism , SARS-CoV-2 , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Astrocytes/metabolism , Brain Diseases/etiology , Cells, Cultured , Endothelium, Vascular/metabolism , Humans , Microglia/metabolism , Nervous System Diseases/etiology , Primary Cell Culture , Receptor, Angiotensin, Type 2 , Virus Replication
3.
EBioMedicine ; 70: 103512, 2021 Aug.
Article in English | MEDLINE | ID: covidwho-1330766

ABSTRACT

BACKGROUND: Neurologic manifestations are well-recognized features of coronavirus disease 2019 (COVID-19). However, the longitudinal association of biomarkers reflecting CNS impact and neurological symptoms is not known. We sought to determine whether plasma biomarkers of CNS injury were associated with neurologic sequelae after COVID-19. METHODS: Patients with confirmed acute COVID-19 were studied prospectively. Neurological symptoms were recorded during the acute phase of the disease and at six months follow-up, and blood samples were collected longitudinally. Healthy age-matched individuals were included as controls. We analysed plasma concentrations of neurofilament light-chain (NfL), glial fibrillary acidic protein (GFAp), and growth differentiation factor 15 (GDF-15). FINDINGS: One hundred patients with mild (n = 24), moderate (n = 28), and severe (n = 48) COVID-19 were followed for a median (IQR) of 225 (187-262) days. In the acute phase, patients with severe COVID-19 had higher concentrations of NfL than all other groups (all p < 0·001), and higher GFAp than controls (p < 0·001). GFAp was also significantly increased in moderate disease (p < 0·05) compared with controls. NfL (r = 0·53, p < 0·001) and GFAp (r = 0·39, p < 0·001) correlated with GDF-15 during the acute phase. After six months, NfL and GFAp concentrations had normalized, with no persisting group differences. Despite this, 50 patients reported persistent neurological symptoms, most commonly fatigue (n = 40), "brain-fog" (n = 29), and changes in cognition (n = 25). We found no correlation between persistent neurological symptoms and CNS injury biomarkers in the acute phase. INTERPRETATION: The normalization of CNS injury biomarkers in all individuals, regardless of previous disease severity or persisting neurological symptoms, indicates that post COVID-19 neurological sequelae are not accompanied by ongoing CNS injury. FUNDING: The Swedish State Support for Clinical Research, SciLifeLab Sweden, and the Knut and Alice Wallenberg Foundation have provided funding for this project.


Subject(s)
Astrocytes/pathology , Astrocytes/virology , COVID-19/pathology , COVID-19/virology , SARS-CoV-2/pathogenicity , Aged , Astrocytes/metabolism , Biomarkers/blood , Biomarkers/metabolism , COVID-19/blood , COVID-19/metabolism , Disease Progression , Female , Follow-Up Studies , Glial Fibrillary Acidic Protein/metabolism , Humans , Longitudinal Studies , Male , Middle Aged , Neurofilament Proteins/metabolism , Neurons/metabolism , Neurons/pathology , Neurons/virology , Sweden
4.
Mol Neurobiol ; 58(10): 5356-5368, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1326854

ABSTRACT

The pandemic of novel coronavirus 2 (SARS-CoV-2) has made global chaos for normal human living. Despite common COVID-19 symptoms, variability in clinical phenotypes was reported worldwide. Reports on SARS-CoV-2 suggest causing neurological manifestation. In addition, the susceptibility of SARS-CoV-2 in patients with neurodegenerative diseases and its complexity are largely unclear. Here, we aimed to demonstrate the possible transport of exosome from SARS-CoV-2-infected lungs to the brain regions associated with neurodegenerative diseases using multiple transcriptome datasets of SARS-CoV-2-infected lungs, RNA profiles from lung exosome, and gene expression profiles of the human brain. Upon transport, the transcription factors localized in the exosome regulate genes at lateral substantia nigra, medial substantia nigra, and superior frontal gyrus regions of Parkinson's disease (PD) and frontal cortex, hippocampus, and temporal cortex of Alzheimer's disease (AD). On SARS-CoV-2 infection, BCL3, JUND, MXD1, IRF2, IRF9, and STAT1 transcription factors in the exosomes influence the neuronal gene regulatory network and accelerate neurodegeneration. STAT1 transcription factor regulates 64 PD genes at lateral substantia nigra, 65 at superior frontal gyrus, and 19 at medial substantia nigra. Similarly, in AD, STAT1 regulates 74 AD genes at the temporal cortex, 40 genes at the hippocampus, and 16 genes at the frontal cortex. We further demonstrate that dysregulated neuronal genes showed involvement in immune response, signal transduction, apoptosis, and stress response process. In conclusion, SARS-CoV-2 may dysregulate neuronal gene regulatory network through exosomes that attenuate disease severity of neurodegeneration.


Subject(s)
Brain/metabolism , COVID-19/metabolism , Exosomes/metabolism , Lung/metabolism , Neurons/metabolism , Alzheimer Disease/genetics , Alzheimer Disease/metabolism , Databases, Factual , Exosomes/genetics , Humans , Parkinson Disease/genetics , Parkinson Disease/metabolism , Transcriptome
5.
J Neurosci ; 41(25): 5338-5349, 2021 06 23.
Article in English | MEDLINE | ID: covidwho-1282334

ABSTRACT

Clinical reports suggest that the coronavirus disease-19 (COVID-19) pandemic caused by severe acute respiratory syndrome (SARS)-coronavirus-2 (CoV-2) has not only taken millions of lives, but has also created a major crisis of neurologic complications that persist even after recovery from the disease. Autopsies of patients confirm the presence of the coronaviruses in the CNS, especially in the brain. The invasion and transmission of SARS-CoV-2 in the CNS is not clearly defined, but, because the endocytic pathway has become an important target for the development of therapeutic strategies for COVID-19, it is necessary to understand endocytic processes in the CNS. In addition, mitochondria and mechanistic target of rapamycin (mTOR) signaling pathways play a critical role in the antiviral immune response, and may also be critical for endocytic activity. Furthermore, dysfunctions of mitochondria and mTOR signaling pathways have been associated with some high-risk conditions such as diabetes and immunodeficiency for developing severe complications observed in COVID-19 patients. However, the role of these pathways in SARS-CoV-2 infection and spread are largely unknown. In this review, we discuss the potential mechanisms of SARS-CoV-2 entry into the CNS and how mitochondria and mTOR pathways might regulate endocytic vesicle-mitochondria interactions and dynamics during SARS-CoV-2 infection. The mechanisms that plausibly account for severe neurologic complications with COVID-19 and potential treatments with Food and Drug Administration-approved drugs targeting mitochondria and the mTOR pathways are also addressed.


Subject(s)
COVID-19/complications , Nervous System Diseases/virology , Neurons/virology , Animals , COVID-19/drug therapy , COVID-19/metabolism , COVID-19/pathology , COVID-19/virology , Humans , Mitochondria/metabolism , Mitochondria/virology , Nervous System Diseases/drug therapy , Nervous System Diseases/metabolism , Nervous System Diseases/pathology , Neurons/metabolism , SARS-CoV-2/pathogenicity , TOR Serine-Threonine Kinases/metabolism
6.
Am J Respir Cell Mol Biol ; 65(4): 403-412, 2021 10.
Article in English | MEDLINE | ID: covidwho-1237350

ABSTRACT

Mechanical ventilation is a known risk factor for delirium, a cognitive impairment characterized by dysfunction of the frontal cortex and hippocampus. Although IL-6 is upregulated in mechanical ventilation-induced lung injury (VILI) and may contribute to delirium, it is not known whether the inhibition of systemic IL-6 mitigates delirium-relevant neuropathology. To histologically define neuropathological effects of IL-6 inhibition in an experimental VILI model, VILI was simulated in anesthetized adult mice using a 35 cc/kg tidal volume mechanical ventilation model. There were two control groups, as follow: 1) spontaneously breathing or 2) anesthetized and mechanically ventilated with 10 cc/kg tidal volume to distinguish effects of anesthesia from VILI. Two hours before inducing VILI, mice were treated with either anti-IL-6 antibody, anti-IL-6 receptor antibody, or saline. Neuronal injury, stress, and inflammation were assessed using immunohistochemistry. CC3 (cleaved caspase-3), a neuronal apoptosis marker, was significantly increased in the frontal (P < 0.001) and hippocampal (P < 0.0001) brain regions and accompanied by significant increases in c-Fos and heat shock protein-90 in the frontal cortices of VILI mice compared with control mice (P < 0.001). These findings were not related to cerebral hypoxia, and there was no evidence of irreversible neuronal death. Frontal and hippocampal neuronal CC3 were significantly reduced with anti-IL-6 antibody (P < 0.01 and P < 0.0001, respectively) and anti-IL-6 receptor antibody (P < 0.05 and P < 0.0001, respectively) compared with saline VILI mice. In summary, VILI induces potentially reversible neuronal injury and inflammation in the frontal cortex and hippocampus, which is mitigated with systemic IL-6 inhibition. These data suggest a potentially novel neuroprotective role of systemic IL-6 inhibition that justifies further investigation.


Subject(s)
Antibodies/pharmacology , Apoptosis/drug effects , Delirium/metabolism , Interleukin-6/antagonists & inhibitors , Neurons/metabolism , Ventilator-Induced Lung Injury/metabolism , Animals , Delirium/drug therapy , Delirium/pathology , Disease Models, Animal , Female , Frontal Lobe/injuries , Frontal Lobe/metabolism , Frontal Lobe/pathology , HSP90 Heat-Shock Proteins/metabolism , Hippocampus/injuries , Hippocampus/metabolism , Hippocampus/pathology , Inflammation/drug therapy , Inflammation/metabolism , Inflammation/pathology , Interleukin-6/metabolism , Mice , Neurons/pathology , Proto-Oncogene Proteins c-fos/metabolism , Repressor Proteins/metabolism , Tumor Suppressor Proteins/metabolism , Ventilator-Induced Lung Injury/drug therapy , Ventilator-Induced Lung Injury/pathology
7.
Signal Transduct Target Ther ; 6(1): 169, 2021 04 24.
Article in English | MEDLINE | ID: covidwho-1199270

ABSTRACT

Neurological manifestations are frequently reported in the COVID-19 patients. Neuromechanism of SARS-CoV-2 remains to be elucidated. In this study, we explored the mechanisms of SARS-CoV-2 neurotropism via our established non-human primate model of COVID-19. In rhesus monkey, SARS-CoV-2 invades the CNS primarily via the olfactory bulb. Thereafter, viruses rapidly spread to functional areas of the central nervous system, such as hippocampus, thalamus, and medulla oblongata. The infection of SARS-CoV-2 induces the inflammation possibly by targeting neurons, microglia, and astrocytes in the CNS. Consistently, SARS-CoV-2 infects neuro-derived SK-N-SH, glial-derived U251, and brain microvascular endothelial cells in vitro. To our knowledge, this is the first experimental evidence of SARS-CoV-2 neuroinvasion in the NHP model, which provides important insights into the CNS-related pathogenesis of SARS-CoV-2.


Subject(s)
Brain Diseases/metabolism , Brain/metabolism , COVID-19/metabolism , Olfactory Bulb/metabolism , SARS-CoV-2/metabolism , Animals , Astrocytes/metabolism , Astrocytes/pathology , Astrocytes/virology , Brain/pathology , Brain/virology , Brain Diseases/pathology , Brain Diseases/virology , COVID-19/pathology , Disease Models, Animal , Humans , Macaca mulatta , Microglia/metabolism , Microglia/pathology , Microglia/virology , Neurons/metabolism , Neurons/pathology , Neurons/virology , Olfactory Bulb/pathology , Olfactory Bulb/virology
8.
Int J Mol Sci ; 22(1)2020 Dec 25.
Article in English | MEDLINE | ID: covidwho-1001758

ABSTRACT

Angiotensin converting enzyme 2 (ACE2) is a critical component of the compensatory axis of the renin angiotensin system. Alterations in ACE2 gene and protein expression, and activity mediated by A Disintegrin And Metalloprotease 17 (ADAM17), a member of the "A Disintegrin And Metalloprotease" (ADAM) family are implicated in several cardiovascular and neurodegenerative diseases. We previously reported that activation of kinin B1 receptor (B1R) in the brain increases neuroinflammation, oxidative stress and sympathoexcitation, leading to the development of neurogenic hypertension. We also showed evidence for ADAM17-mediated ACE2 shedding in neurons. However, whether kinin B1 receptor (B1R) activation has any role in altering ADAM17 activity and its effect on ACE2 shedding in neurons is not known. In this study, we tested the hypothesis that activation of B1R upregulates ADAM17 and results in ACE2 shedding in neurons. To test this hypothesis, we stimulated wild-type and B1R gene-deleted mouse neonatal primary hypothalamic neuronal cultures with a B1R-specific agonist and measured the activities of ADAM17 and ACE2 in neurons. B1R stimulation significantly increased ADAM17 activity and decreased ACE2 activity in wild-type neurons, while pretreatment with a B1R-specific antagonist, R715, reversed these changes. Stimulation with specific B1R agonist Lys-Des-Arg9-Bradykinin (LDABK) did not show any effect on ADAM17 or ACE2 activities in neurons with B1R gene deletion. These data suggest that B1R activation results in ADAM17-mediated ACE2 shedding in primary hypothalamic neurons. In addition, stimulation with high concentration of glutamate significantly increased B1R gene and protein expression, along with increased ADAM17 and decreased ACE2 activities in wild-type neurons. Pretreatment with B1R-specific antagonist R715 reversed these glutamate-induced effects suggesting that indeed B1R is involved in glutamate-mediated upregulation of ADAM17 activity and ACE2 shedding.


Subject(s)
ADAM17 Protein/metabolism , Angiotensin-Converting Enzyme 2/metabolism , Neurons/metabolism , Animals , Cells, Cultured , Gene Expression Regulation/drug effects , Glutamic Acid/metabolism , Glutamic Acid/pharmacology , Hypothalamus/metabolism , Mice , Mice, Knockout , Models, Biological , Pyramidal Cells/metabolism
9.
Cells ; 10(2)2021 02 16.
Article in English | MEDLINE | ID: covidwho-1106076

ABSTRACT

Parkinson's disease (PD) is the second most common neurodegenerative disease, afflicting ~10 million people worldwide. Although several genes linked to PD are currently identified, PD remains primarily an idiopathic disorder. Neuronal protein α-synuclein is a major player in disease progression of both genetic and idiopathic forms of PD. However, it cannot alone explain underlying pathological processes. Recent studies demonstrate that many other risk factors can accelerate or further worsen brain dysfunction in PD patients. Several PD models, including non-mammalian eukaryotic organisms, have been developed to identify and characterize these factors. This review discusses recent findings in three PD model organisms, i.e., yeast, Drosophila, and Caenorhabditis elegans, that opened new mechanisms and identified novel contributors to this disorder. These non-mammalian models share many conserved molecular pathways and cellular processes with humans. New players affecting PD pathogenesis include previously unknown genes/proteins, novel signaling pathways, and low molecular weight substances. These findings might respond to the urgent need to discover novel drug targets for PD treatment and new biomarkers for early diagnostics of this disease. Since the study of neurodegeneration using simple eukaryotic organisms brought a huge amount of information, we include only the most recent or the most important relevant data.


Subject(s)
Animals, Genetically Modified/metabolism , Neurodegenerative Diseases/metabolism , Neurons/metabolism , Parkinson Disease/metabolism , Animals , Animals, Genetically Modified/genetics , Caenorhabditis elegans/metabolism , Disease Models, Animal , Humans
10.
Stem Cell Reports ; 16(3): 437-445, 2021 03 09.
Article in English | MEDLINE | ID: covidwho-1084274

ABSTRACT

COVID-19 is a transmissible respiratory disease caused by a novel coronavirus, SARS-CoV-2, and has become a global health emergency. There is an urgent need for robust and practical in vitro model systems to investigate viral pathogenesis. Here, we generated human induced pluripotent stem cell (iPSC)-derived lung organoids (LORGs), cerebral organoids (CORGs), neural progenitor cells (NPCs), neurons, and astrocytes. LORGs containing epithelial cells, alveolar types 1 and 2, highly express ACE2 and TMPRSS2 and are permissive to SARS-CoV-2 infection. SARS-CoV-2 infection induces interferons, cytokines, and chemokines and activates critical inflammasome pathway genes. Spike protein inhibitor, EK1 peptide, and TMPRSS2 inhibitors (camostat/nafamostat) block viral entry in LORGs. Conversely, CORGs, NPCs, astrocytes, and neurons express low levels of ACE2 and TMPRSS2 and correspondingly are not highly permissive to SARS-CoV-2 infection. Infection in neuronal cells activates TLR3/7, OAS2, complement system, and apoptotic genes. These findings will aid in understanding COVID-19 pathogenesis and facilitate drug discovery.


Subject(s)
Brain/virology , COVID-19/virology , Induced Pluripotent Stem Cells/virology , Lung/virology , Neural Stem Cells/virology , Organoids/virology , SARS-CoV-2/pathogenicity , Apoptosis/physiology , Brain/metabolism , COVID-19/metabolism , Cells, Cultured , Complement System Proteins/metabolism , Epithelial Cells/metabolism , Epithelial Cells/virology , Humans , Induced Pluripotent Stem Cells/metabolism , Inflammation/metabolism , Inflammation/virology , Lung/metabolism , Neural Stem Cells/metabolism , Neurons/metabolism , Neurons/virology , Organoids/metabolism , Serine Endopeptidases/metabolism , Signal Transduction/physiology , Stem Cells/metabolism , Stem Cells/virology
11.
Nature ; 588(7838): 466-472, 2020 12.
Article in English | MEDLINE | ID: covidwho-1075229

ABSTRACT

Cardiovascular disease is the leading cause of death worldwide. Advanced insights into disease mechanisms and therapeutic strategies require a deeper understanding of the molecular processes involved in the healthy heart. Knowledge of the full repertoire of cardiac cells and their gene expression profiles is a fundamental first step in this endeavour. Here, using state-of-the-art analyses of large-scale single-cell and single-nucleus transcriptomes, we characterize six anatomical adult heart regions. Our results highlight the cellular heterogeneity of cardiomyocytes, pericytes and fibroblasts, and reveal distinct atrial and ventricular subsets of cells with diverse developmental origins and specialized properties. We define the complexity of the cardiac vasculature and its changes along the arterio-venous axis. In the immune compartment, we identify cardiac-resident macrophages with inflammatory and protective transcriptional signatures. Furthermore, analyses of cell-to-cell interactions highlight different networks of macrophages, fibroblasts and cardiomyocytes between atria and ventricles that are distinct from those of skeletal muscle. Our human cardiac cell atlas improves our understanding of the human heart and provides a valuable reference for future studies.


Subject(s)
Myocardium/cytology , Single-Cell Analysis , Transcriptome , Adipocytes/classification , Adipocytes/metabolism , Adult , Angiotensin-Converting Enzyme 2/analysis , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Epithelial Cells/classification , Epithelial Cells/metabolism , Epithelium , Female , Fibroblasts/classification , Fibroblasts/metabolism , Gene Expression Profiling , Genome-Wide Association Study , Heart Atria/anatomy & histology , Heart Atria/cytology , Heart Atria/innervation , Heart Ventricles/anatomy & histology , Heart Ventricles/cytology , Heart Ventricles/innervation , Homeostasis/immunology , Humans , Macrophages/immunology , Macrophages/metabolism , Male , Muscle, Skeletal/cytology , Muscle, Skeletal/metabolism , Myocytes, Cardiac/classification , Myocytes, Cardiac/metabolism , Neurons/classification , Neurons/metabolism , Pericytes/classification , Pericytes/metabolism , Receptors, Coronavirus/analysis , Receptors, Coronavirus/genetics , Receptors, Coronavirus/metabolism , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Stromal Cells/classification , Stromal Cells/metabolism
12.
Drug Discov Ther ; 14(6): 262-272, 2021 Jan 23.
Article in English | MEDLINE | ID: covidwho-1067907

ABSTRACT

The novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified in 2019 in Wuhan, China. Clinically, respiratory tract symptoms as well as other organs disorders are observed in patients positively diagnosed coronavirus disease 2019 (COVID-19). In addition, neurological symptoms, mainly anosmia, ageusia and headache were observed in many patients. Once in the central nervous system (CNS), the SARS-CoV-2 can reside either in a quiescent latent state, or eventually in actively state leading to severe acute encephalitis, characterized by neuroinflammation and prolonged neuroimmune activation. SRAS-CoV-2 requires angiotensin-converting enzyme 2 (ACE2) as a cell entry receptor. The expression of this receptor in endothelial cells of blood-brain barrier (BBB) shows that SRAS-CoV-2 may have higher neuroinvasive potential compared to known coronaviruses. This review summarizes available information regarding the impact of SRAS-CoV-2 in the brain and tended to identify its potential pathways of neuroinvasion. We offer also an understanding of the long-term impact of latently form of SARS-CoV-2 on the development of neurodegenerative disorders. As a conclusion, the persistent infection of SRAS-CoV-2 in the brain could be involved on human neurodegenerative diseases that evolve a gradual process, perhapes, over several decades.


Subject(s)
COVID-19/virology , Central Nervous System Viral Diseases/virology , Neurodegenerative Diseases/virology , Neurons/virology , SARS-CoV-2/pathogenicity , Viral Tropism , Animals , COVID-19/complications , Central Nervous System Viral Diseases/metabolism , Central Nervous System Viral Diseases/pathology , Host-Pathogen Interactions , Humans , Neurodegenerative Diseases/metabolism , Neurodegenerative Diseases/pathology , Neurons/metabolism , Neurons/pathology , Virus Latency
13.
Brain Behav Immun ; 91: 740-755, 2021 01.
Article in English | MEDLINE | ID: covidwho-1064860

ABSTRACT

Central nervous system (CNS) innate immunity plays essential roles in infections, neurodegenerative diseases, and brain or spinal cord injuries. Astrocytes and microglia are the principal cells that mediate innate immunity in the CNS. Pattern recognition receptors (PRRs), expressed by astrocytes and microglia, sense pathogen-derived or endogenous ligands released by damaged cells and initiate the innate immune response. Toll-like receptors (TLRs) are a well-characterized family of PRRs. The contribution of microglial TLR signaling to CNS pathology has been extensively investigated. Even though astrocytes assume a wide variety of key functions, information about the role of astroglial TLRs in CNS disease and injuries is limited. Because astrocytes display heterogeneity and exhibit phenotypic plasticity depending on the effectors present in the local milieu, they can exert both detrimental and beneficial effects. TLRs are modulators of these paradoxical astroglial properties. The goal of the current review is to highlight the essential roles played by astroglial TLRs in CNS infections, injuries and diseases. We discuss the contribution of astroglial TLRs to host defense as well as the dissemination of viral and bacterial infections in the CNS. We examine the link between astroglial TLRs and the pathogenesis of neurodegenerative diseases and present evidence showing the pivotal influence of astroglial TLR signaling on sterile inflammation in CNS injury. Finally, we define the research questions and areas that warrant further investigations in the context of astrocytes, TLRs, and CNS dysfunction.


Subject(s)
Astrocytes/metabolism , Neurodegenerative Diseases/physiopathology , Toll-Like Receptors/physiology , Animals , Astrocytes/physiology , Brain/metabolism , Central Nervous System/immunology , Central Nervous System/metabolism , Central Nervous System Diseases/immunology , Central Nervous System Infections/pathology , Encephalitis/immunology , Humans , Immunity, Innate/physiology , Microglia/metabolism , Neurodegenerative Diseases/metabolism , Neurons/metabolism , Receptors, Pattern Recognition/immunology , Signal Transduction , Spinal Cord/pathology , Spinal Cord Injuries/pathology , Toll-Like Receptors/metabolism
14.
Med Sci Monit ; 27: e930886, 2021 Jan 25.
Article in English | MEDLINE | ID: covidwho-1045272

ABSTRACT

Alterations in brain functioning, especially in regions associated with cognition, can result from infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and are predicted to result in various psychiatric diseases. Recent studies have shown that SARS-CoV-2 infection and coronavirus disease 2019 (COVID-19) can directly or indirectly affect the central nervous system (CNS). Therefore, diseases associated with sequelae of COVID-19, or 'long COVID', also include serious long-term mental and cognitive changes, including the condition recently termed 'brain fog'. Hypoxia in the microenvironment of select brain areas may benefit the reproductive capacity of the virus. It is possible that in areas of cerebral hypoxia, neuronal cell energy metabolism may become compromised after integration of the viral genome, resulting in mitochondrial dysfunction. Because of their need for constant high metabolism, cerebral tissues require an immediate and constant supply of oxygen. In hypoxic conditions, neurons with the highest oxygen demand become dysfunctional. The resulting cognitive impairment benefits viral spread, as infected individuals exhibit behaviors that reduce protection against infection. The effects of compromised mitochondrial function may also be an evolutionary advantage for SARS-CoV-2 in terms of host interaction. A high viral load in patients with COVID-19 that involves the CNS results in the compromise of neurons with high-level energy metabolism. Therefore, we propose that selective neuronal mitochondrial targeting in SARS-CoV-2 infection affects cognitive processes to induce 'brain fog' and results in behavioral changes that favor viral propagation. Cognitive changes associated with COVID-19 will have increasing significance for patient diagnosis, prognosis, and long-term care.


Subject(s)
COVID-19/metabolism , Cognitive Dysfunction/metabolism , Health Behavior , Hypoxia, Brain/metabolism , Mitochondria/metabolism , Neurons/metabolism , SARS-CoV-2/physiology , COVID-19/complications , COVID-19/physiopathology , COVID-19/psychology , COVID-19/transmission , Cognitive Dysfunction/physiopathology , Cognitive Dysfunction/psychology , Energy Metabolism , Humans , Hypoxia, Brain/physiopathology , Hypoxia, Brain/psychology , Microbial Viability , Viral Load , Virus Replication
15.
J Exp Med ; 218(3)2021 03 01.
Article in English | MEDLINE | ID: covidwho-1024074

ABSTRACT

Although COVID-19 is considered to be primarily a respiratory disease, SARS-CoV-2 affects multiple organ systems including the central nervous system (CNS). Yet, there is no consensus on the consequences of CNS infections. Here, we used three independent approaches to probe the capacity of SARS-CoV-2 to infect the brain. First, using human brain organoids, we observed clear evidence of infection with accompanying metabolic changes in infected and neighboring neurons. However, no evidence for type I interferon responses was detected. We demonstrate that neuronal infection can be prevented by blocking ACE2 with antibodies or by administering cerebrospinal fluid from a COVID-19 patient. Second, using mice overexpressing human ACE2, we demonstrate SARS-CoV-2 neuroinvasion in vivo. Finally, in autopsies from patients who died of COVID-19, we detect SARS-CoV-2 in cortical neurons and note pathological features associated with infection with minimal immune cell infiltrates. These results provide evidence for the neuroinvasive capacity of SARS-CoV-2 and an unexpected consequence of direct infection of neurons by SARS-CoV-2.


Subject(s)
Angiotensin-Converting Enzyme 2 , Antibodies, Blocking/chemistry , COVID-19 , Cerebral Cortex , Neurons , SARS-CoV-2/metabolism , Angiotensin-Converting Enzyme 2/antagonists & inhibitors , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/metabolism , COVID-19/pathology , Cerebral Cortex/metabolism , Cerebral Cortex/pathology , Cerebral Cortex/virology , Disease Models, Animal , Female , Humans , Male , Mice , Middle Aged , Neurons/metabolism , Neurons/pathology , Neurons/virology , Organoids/metabolism , Organoids/pathology , Organoids/virology
16.
Biomedica ; 40(1): 14-19, 2020 03 01.
Article in English, Spanish | MEDLINE | ID: covidwho-922941

ABSTRACT

The term 'porphyria' comes from the Greek 'porphyra'. It refers to a heterogeneous group of metabolic disorders caused by the enzymatic deficiency in the biosynthesis of the heme group. Acute intermittent porphyria is caused by a deficiency of the porphobilinogen deaminase enzyme. A 40-year-old woman presented with abdominal pain for ten days (which required laparotomy that evidenced no surgical pathology), severe hydroelectrolytic disorder due to hyponatremia and resistant hypokalemia, persistent tachycardia and hypertension. Seven days later, she developed acute flabby quadriparesis and presented a single generalized tonic-clonic convulsive crisis. Neurophysiological studies supported mixed axonal polyneuropathy and urine results of porphobilinogen and porphyrins were elevated. After acute intermittent porphyria was diagnosed, hemin was administered, which stabilized the patient's clinical signs and normalized the porphobilinogen. The prevalence of this entity is 1 in 2,000 people. It is an autosomal dominant disease, which affects mainly women between 20 and 40 years of age. This entity manifests with neurological and visceral symptoms. Management consists of hematin and dextrose administration avoiding hypotonic solutions because of the risk of exacerbating hyponatremia.


El término 'porfiria' proviene del griego 'porphyra' y alude a un grupo heterogéneo de trastornos metabólicos causados por una deficiencia enzimática en la biosíntesis del grupo hemo. La causa de la porfiria intermitente aguda es la deficiencia de la enzima deaminasa del porfobilinógeno. Se presenta el caso de una mujer de 40 años que presentó dolor abdominal de 10 días de evolución, trastorno hidroelectrolítico grave debido a hiponatremia e hipopotasemia, taquicardia e hipertensión arterial sistémica persistentes, por lo cual fue sometida a una laparotomía en la que no se encontró ninguna afección de origen quirúrgico, A los siete días del examen inicial, la paciente desarrolló cuadriparesia flácida aguda y presentó una crisis convulsiva tónico-clónica generalizada. Los estudios neurofisiológicos evidenciaron una polineuropatía axonal mixta, y los valores de porfobilinógeno y porfirinas en orina eran elevados. Tras diagnosticarse porfiria intermitente aguda, esta se trató con hemina, lo que estabilizó los signos clínicos y normalizó el porfobilinógeno. La prevalencia de esta enfermedad es de 1 en 2.000 personas. Tiene un patrón de herencia autosómico dominante y se manifiesta principalmente en mujeres con edades entre los 20 y los 40 años. La enfermedad cursa con síntomas neurológicos y viscerales, y se trata con la administración de hemina y dextrosa, evitando las soluciones hipotónicas por el riesgo de exacerbar la hiponatremia.


Subject(s)
Porphyria, Acute Intermittent/diagnosis , Delayed Diagnosis , Female , Gastrointestinal Diseases/etiology , Hemin/therapeutic use , Humans , Neurons/metabolism , Porphobilinogen/urine , Porphyria, Acute Intermittent/complications , Porphyria, Acute Intermittent/drug therapy , Porphyria, Acute Intermittent/epidemiology , Porphyrins/urine , Prevalence , Quadriplegia/etiology , Respiration, Artificial , Respiratory Insufficiency/etiology , Respiratory Insufficiency/therapy , Seizures/etiology , Symptom Assessment , Water-Electrolyte Imbalance/etiology , Young Adult
17.
J Virol ; 94(20)2020 09 29.
Article in English | MEDLINE | ID: covidwho-840609

ABSTRACT

Alpha/beta interferon (IFN-α/ß) signaling through the IFN-α/ß receptor (IFNAR) is essential to limit virus dissemination throughout the central nervous system (CNS) following many neurotropic virus infections. However, the distinct expression patterns of factors associated with the IFN-α/ß pathway in different CNS resident cell populations implicate complex cooperative pathways in IFN-α/ß induction and responsiveness. Here we show that mice devoid of IFNAR1 signaling in calcium/calmodulin-dependent protein kinase II alpha (CaMKIIα) expressing neurons (CaMKIIcre:IFNARfl/fl mice) infected with a mildly pathogenic neurotropic coronavirus (mouse hepatitis virus A59 strain [MHV-A59]) developed severe encephalomyelitis with hind-limb paralysis and succumbed within 7 days. Increased virus spread in CaMKIIcre:IFNARfl/fl mice compared to IFNARfl/fl mice affected neurons not only in the forebrain but also in the mid-hind brain and spinal cords but excluded the cerebellum. Infection was also increased in glia. The lack of viral control in CaMKIIcre:IFNARfl/fl relative to control mice coincided with sustained Cxcl1 and Ccl2 mRNAs but a decrease in mRNA levels of IFNα/ß pathway genes as well as Il6, Tnf, and Il1ß between days 4 and 6 postinfection (p.i.). T cell accumulation and IFN-γ production, an essential component of virus control, were not altered. However, IFN-γ responsiveness was impaired in microglia/macrophages irrespective of similar pSTAT1 nuclear translocation as in infected controls. The results reveal how perturbation of IFN-α/ß signaling in neurons can worsen disease course and disrupt complex interactions between the IFN-α/ß and IFN-γ pathways in achieving optimal antiviral responses.IMPORTANCE IFN-α/ß induction limits CNS viral spread by establishing an antiviral state, but also promotes blood brain barrier integrity, adaptive immunity, and activation of microglia/macrophages. However, the extent to which glial or neuronal signaling contributes to these diverse IFN-α/ß functions is poorly understood. Using a neurotropic mouse hepatitis virus encephalomyelitis model, this study demonstrated an essential role of IFN-α/ß receptor 1 (IFNAR1) specifically in neurons to control virus spread, regulate IFN-γ signaling, and prevent acute mortality. The results support the notion that effective neuronal IFNAR1 signaling compensates for their low basal expression of genes in the IFN-α/ß pathway compared to glia. The data further highlight the importance of tightly regulated communication between the IFN-α/ß and IFN-γ signaling pathways to optimize antiviral IFN-γ activity.


Subject(s)
Central Nervous System/virology , Interferon Type I/metabolism , Interferon-gamma/metabolism , Macrophages/metabolism , Microglia/metabolism , Neurons/metabolism , Signal Transduction , Animals , Calcium-Calmodulin-Dependent Protein Kinase Type 2/genetics , Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism , Central Nervous System/immunology , Coronavirus Infections/immunology , Coronavirus Infections/virology , Disease Models, Animal , Encephalomyelitis/immunology , Encephalomyelitis/virology , Macrophages/virology , Mice , Mice, Mutant Strains , Microglia/virology , Murine hepatitis virus/physiology , Neurons/virology , Neutrophil Infiltration , Receptor, Interferon alpha-beta/deficiency , Receptor, Interferon alpha-beta/genetics , Receptor, Interferon alpha-beta/metabolism , Virus Replication
18.
Neurology ; 95(12): e1754-e1759, 2020 09 22.
Article in English | MEDLINE | ID: covidwho-601304

ABSTRACT

OBJECTIVE: To test the hypothesis that coronavirus disease 2019 (COVID-19) has an impact on the CNS by measuring plasma biomarkers of CNS injury. METHODS: We recruited 47 patients with mild (n = 20), moderate (n = 9), or severe (n = 18) COVID-19 and measured 2 plasma biomarkers of CNS injury by single molecule array, neurofilament light chain protein (NfL; a marker of intra-axonal neuronal injury) and glial fibrillary acidic protein (GFAp; a marker of astrocytic activation/injury), in samples collected at presentation and again in a subset after a mean of 11.4 days. Cross-sectional results were compared with results from 33 age-matched controls derived from an independent cohort. RESULTS: The patients with severe COVID-19 had higher plasma concentrations of GFAp (p = 0.001) and NfL (p < 0.001) than controls, while GFAp was also increased in patients with moderate disease (p = 0.03). In patients with severe disease, an early peak in plasma GFAp decreased on follow-up (p < 0.01), while NfL showed a sustained increase from first to last follow-up (p < 0.01), perhaps reflecting a sequence of early astrocytic response and more delayed axonal injury. CONCLUSION: We show neurochemical evidence of neuronal injury and glial activation in patients with moderate and severe COVID-19. Further studies are needed to clarify the frequency and nature of COVID-19-related CNS damage and its relation to both clinically defined CNS events such as hypoxic and ischemic events and mechanisms more closely linked to systemic severe acute respiratory syndrome coronavirus 2 infection and consequent immune activation, as well as to evaluate the clinical utility of monitoring plasma NfL and GFAp in the management of this group of patients.


Subject(s)
Astrocytes/metabolism , Coronavirus Infections/blood , Glial Fibrillary Acidic Protein/blood , Neurofilament Proteins/blood , Neurons/metabolism , Pneumonia, Viral/blood , Adult , Age Factors , Aged , Betacoronavirus , Biomarkers/blood , COVID-19 , Case-Control Studies , Female , Follow-Up Studies , Humans , Male , Middle Aged , Pandemics , SARS-CoV-2 , Severity of Illness Index , Single Molecule Imaging
19.
Neurotox Res ; 38(1): 1-7, 2020 Jun.
Article in English | MEDLINE | ID: covidwho-244976

ABSTRACT

As a severe and highly contagious infectious disease, coronavirus disease 2019 (COVID-19) has caused a global pandemic. Several case reports have demonstrated that the respiratory system is the main target in patients with COVID-19, but the disease is not limited to the respiratory system. Case analysis indicated that the nervous system can be invaded by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and that 36.4% of COVID-19 patients had neurological symptoms. Importantly, the involvement of the CNS may be associated with poor prognosis and disease worsening. Here, we discussed the symptoms and evidence of nervous system involvement (directly and indirectly) caused by SARS-CoV-2 infection and possible mechanisms. CNS symptoms could be a potential indicator of poor prognosis; therefore, the prevention and treatment of CNS symptoms are also crucial for the recovery of COVID-19 patients.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/complications , Nervous System Diseases/etiology , Pneumonia, Viral/complications , Angiotensin-Converting Enzyme 2 , COVID-19 , Cerebrovascular Disorders/epidemiology , Cerebrovascular Disorders/etiology , Combined Modality Therapy , Consciousness Disorders/epidemiology , Consciousness Disorders/etiology , Coronavirus Infections/psychology , Coronavirus Infections/virology , Dizziness/epidemiology , Dizziness/etiology , Encephalitis, Viral/epidemiology , Encephalitis, Viral/etiology , Endothelial Cells/metabolism , Endothelial Cells/virology , Fatigue/epidemiology , Fatigue/etiology , Headache/epidemiology , Headache/etiology , Humans , Intracranial Hypertension/epidemiology , Intracranial Hypertension/etiology , Mental Disorders/drug therapy , Mental Disorders/epidemiology , Mental Disorders/etiology , Mental Disorders/therapy , Mood Disorders/drug therapy , Mood Disorders/epidemiology , Mood Disorders/etiology , Mood Disorders/therapy , Nervous System Diseases/epidemiology , Neurons/metabolism , Neurons/virology , Olfactory Nerve/virology , Pandemics , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/psychology , Pneumonia, Viral/virology , Prevalence , Prognosis , Psychotherapy , Psychotropic Drugs/therapeutic use , Receptors, Virus/metabolism , Retrospective Studies , SARS-CoV-2 , Sensation Disorders/epidemiology , Sensation Disorders/etiology , Spike Glycoprotein, Coronavirus/metabolism
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