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1.
Multiple Sclerosis Journal ; 28(3 Supplement):839-840, 2022.
Article in English | EMBASE | ID: covidwho-2138787

ABSTRACT

Introduction: There are no effective treatments for non-active secondary progressive MS (SPMS), which is mediated by compartmentalized CNS inflammation, including activated microglia. We found that fully human anti-CD3 intranasal monoclonal antibody (Foralumab) suppressed disease in a chronic EAE model by dampening microglia and astrocyte inflammation. Nasal Foralumab does not enter the bloodstream or brain. A dose-finding study of nasal Foralumab in controls dosed at 10ug, 50ug and 250ug for 5 days found the drug to be safe with immune effects seen at 50ug. COVID patients dosed with 100ug of nasal Foralumab for 10 days was well-tolerated and exhibited positive effects on blood markers and lung inflammation. Objective(s): To determine if nasal Foralumab has a therapeutic effect on patients with non-active SPMS. Method(s): Two patients were identified with non-active SPMS and sustained clinical progression, despite use of approved DMT. EA1 is a 61-year-old male diagnosed for over 20 years and EA2 is a 42-year-old male diagnosed for 8 years, both last treated with ocrelizumab for 3 years. Treatment occurs in 3-week cycles with intranasal Foralumab 50ug/day administered 3x/week for 2 weeks with 1 week rest. Each cycle, clinical and neurological assessments are repeated, and imaging is repeated every 3 months. Result(s): EA1 has completed 6 months and EA2 has completed 3 months of treatment. To date, there have been no adverse reactions, local irritation, or laboratory abnormalities, and symptom progression has subsided. EA1 is feeling more stable, subjectively, and has noted improvement in lower extremity strength. EDSS, pyramidal motor score and T25FW have stabilized or improved. SDMT and 9HPT were stable during treatment. Microglial activation as measured by [F-18]PBR06 PET scan was significantly reduced 3 months after the start of nasal Foralumab, and this reduction was sustained after 7-week washout and at 6 months. Serum protein measurements of cytokines showed reduction of IFN-gamma, IL-18, IL-1s and IL-6 levels (Olink assay). Cellular immune studies showed increase in CD8 naive cells and decrease in CD8 effector cells, and alteration in gene expression as measured by single cell RNA sequencing. EA2 3-month laboratory and imaging results are pending and will be presented. Conclusion(s): Nasal Foralumab in non-active SPMS patients treated for at least 3 months reduced microglial activation, decreased levels of proinflammatory cytokines, and had positive clinical effects.

2.
PeerJ ; 10: e14227, 2022.
Article in English | MEDLINE | ID: covidwho-2110911

ABSTRACT

Persistence of symptoms beyond the initial 3 to 4 weeks after infection is defined as post-acute COVID-19 syndrome (PACS). A wide range of neuropsychiatric symptoms like anxiety, depression, post-traumatic stress disorder, sleep disorders and cognitive disturbances have been observed in PACS. The review was conducted based on PRISMA-S guidelines for literature search strategy for systematic reviews. A cytokine storm in COVID-19 may cause a breach in the blood brain barrier leading to cytokine and SARS-CoV-2 entry into the brain. This triggers an immune response in the brain by activating microglia, astrocytes, and other immune cells leading to neuroinflammation. Various inflammatory biomarkers like inflammatory cytokines, chemokines, acute phase proteins and adhesion molecules have been implicated in psychiatric disorders and play a major role in the precipitation of neuropsychiatric symptoms. Impaired adult neurogenesis has been linked with a variety of disorders like depression, anxiety, cognitive decline, and dementia. Persistence of neuroinflammation was observed in COVID-19 survivors 3 months after recovery. Chronic neuroinflammation alters adult neurogenesis with pro-inflammatory cytokines supressing anti-inflammatory cytokines and chemokines favouring adult neurogenesis. Based on the prevalence of neuropsychiatric symptoms/disorders in PACS, there is more possibility for a potential impairment in adult neurogenesis in COVID-19 survivors. This narrative review aims to discuss the various neuroinflammatory processes during PACS and its effect on adult neurogenesis.

3.
Metabolites ; 12(11)2022 Nov 11.
Article in English | MEDLINE | ID: covidwho-2110179

ABSTRACT

The main neuropathological feature of Alzheimer's disease (AD) is extracellular amyloid deposition in senile plaques, resulting from an imbalance between the production and clearance of amyloid beta peptides. Amyloid deposition is also found around cerebral blood vessels, termed cerebral amyloid angiopathy (CAA), in 90% of AD cases. Although the relationship between these two amyloid disorders is obvious, this does not make CAA a characteristic of AD, as 40% of the non-demented population presents this derangement. AD is predominantly sporadic; therefore, many factors contribute to its genesis. Herein, the starting point for discussion is the COVID-19 pandemic that we are experiencing and how SARS-CoV-2 may be able to, both directly and indirectly, contribute to CAA, with consequences for the outcome and extent of the disease. We highlight the role of astrocytes and endothelial cells in the process of amyloidgenesis, as well as the role of other amyloidgenic proteins, such as fibrinogen and serum amyloid A protein, in addition to the neuronal amyloid precursor protein. We discuss three independent hypotheses that complement each other to explain the cerebrovascular amyloidgenesis that may underlie long-term COVID-19 and new cases of dementia.

4.
Investigative Ophthalmology and Visual Science ; 63(7):975-F0372, 2022.
Article in English | EMBASE | ID: covidwho-2057457

ABSTRACT

Purpose : Different signs of inflammation have been described in the brains of COVID-19 patients. In the retina, the fundus eye exam of these patients shows cotton wool spots, microhemorrhages, and a decrease in vascular density. However, morphological alterations of retinal cells in these patients are unknown. Thus, the aim was to analyze the morphological changes of the retinal cells from human donors with COVID-19 to establish several stages of response to damage in these cells and to define correlations with clinical parameters. Methods : The retinas of human donors with COVID-19 (n = 16) and control subjects (n = 12) obtained from the General University Hospital Consortium of Valencia were analyzed. Immunohistochemical stainings were performed on transversal sections or flat-mount retinas to study photoreceptors, microglial cells, Müller cells, astrocytes, and the presence of ACE2. TUNEL assays and confocal microscopy imaging were carried out. Correlations were calculated between retinal and clinical parameters. Results : Mean age of COVID-19 and control group were 80±10 and 70±8 years respectively. Müller cells, outer segment of cones and retinal pigment epithelium presented ACE2 staining. Larger staining of ACE2 and CRALBP was observed in cell bodies of Müller cells in COVID group. Disorganization of honeycomb-like pattern formed by Müller cells in the outer nuclear layer and disruption of external limiting membrane was found in the 81.3% of COVID patients. The 56.3% of COVID patients showed gliosis compared to controls (40%). COVID-19 retinas also presented epiretinal membranes and astrocytes protruding to vitreous humor. The 93.8% of COVID-19 patients had activated or ameboid-shape microglia. Microglial nodules around vessels and a reduction of the area occupied by microglia in these retinas were observed. COVID-19 group showed a more severe degeneration of cones. Cone degeneration correlated with Müller cell activation. Age of COVID patients correlated inversely with total retinal degeneration. Conclusions : Morphological alterations in the cone photoreceptors as well as glial activation showing an inflammatory state of the retina were observed in COVID-19 patients.

5.
Nano Life ; : 1, 2022.
Article in English | Academic Search Complete | ID: covidwho-2053335

ABSTRACT

Dexamethasone is a synthetic corticosteroid that has historically been used to treat inflammation, such as from osteoarthritis, spinal cord injury and, more recently, COVID-19. The mechanism of action of dexamethasone is generally known to include attenuation of pro-inflammatory responses as well as upregulation of anti-inflammatory elements. A major issue with the use of dexamethasone is its delivery, as it is normally administered in large quantities via methods like bolus injection to attempt to maintain sufficient concentrations days or weeks after administration. In this review, we examine the mechanism of action of dexamethasone and its effects on three major cell types in the context of specific diseases: macrophages in the context of COVID, chondrocytes in the context of osteoarthritis, and astrocytes in the context of neuro-inflammatory disease. From this, we identify the key proinflammatory cytokines interleukin-1 (IL-1) and Tumor Necrosis Factor alpha (TNF-a) as universal effectors of inflammation that should be targeted alongside dexamethasone administration. Additionally, we review current extended release dosing mechanisms for dexamethasone to act over periods of weeks and months. We suggest that dual treatment of dexamethasone with IL-1 and/or TNF-a monoclonal antibodies will be an effective immediate treatment for inflammation, while the addition of fully developed dexamethasone extended release mechanisms will allow for effective long-term control of inflammatory disease. [ FROM AUTHOR] Copyright of Nano Life is the property of World Scientific Publishing Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

6.
Front Cell Neurosci ; 16: 897564, 2022.
Article in English | MEDLINE | ID: covidwho-2002498

ABSTRACT

Patients with coronavirus disease 2019 (COVID-19) have been frequently reported to exhibit neurological manifestations and disruption of the blood-brain barrier (BBB). Among the risk factors for BBB breakdown, the loss of endothelial cells and pericytes has caused widespread concern. Recent studies have revealed that severe acute respiratory syndrome coronavirus 2 envelope (S2E) protein caused cell death. We tested the hypothesis that the S2E protein alone could induce BBB dysfunction. The S2E protein bound to human BBB-related cells and inhibited cell viability in a dose- and time-dependent manner. Importantly, the S2E protein disrupted barrier function in an in vitro BBB model composed of HCMEC/D3 (brain endothelial cell line), HBVP (brain vascular pericyte), and U87MG (astrocyte cell line) cells and suppressed the expression of major genes involved in maintaining endothelial permeability and function. In addition, the S2E protein crossed the HCMEC/D3 monolayer. The S2E protein triggered inflammatory responses in HCMEC/D3 and U87MG cells. Taken together, these results show for the first time that the S2E protein has a negative impact on the BBB. Therapies targeting the S2E protein could protect against and treat central nervous system manifestations in COVID-19 patients.

7.
Brain Disord ; 4: 100021, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1426913

ABSTRACT

Coronaviruses have emerged as alarming pathogens owing to their inherent ability of genetic variation and cross-species transmission. Coronavirus infection burdens the endoplasmic reticulum (ER.), causes reactive oxygen species production and induces host stress responses, including unfolded protein response (UPR) and antioxidant system. In this study, we have employed a neurotropic murine ß-coronavirus (M-CoV) infection in the Central Nervous System (CNS) of experimental mice model to study the role of host stress responses mediated by interplay of DJ-1 and XBP1. DJ-1 is an antioxidant molecule with established functions in neurodegeneration. However, its regulation in virus-induced cellular stress response is less explored. Our study showed that M-CoV infection activated the glial cells and induced antioxidant and UPR genes during the acute stage when the viral titer peaks. As the virus particles decreased and acute neuroinflammation diminished at day ten p.i., a significant up-regulation in UPR responsive XBP1, antioxidant DJ-1, and downstream signaling molecules, including Nrf2, was recorded in the brain tissues. Additionally, preliminary in silico analysis of the binding between the DJ-1 promoter and a positively charged groove of XBP1 is also investigated, thus hinting at a mechanism behind the upregulation of DJ-1 during MHV-infection. The current study thus attempts to elucidate a novel interplay between the antioxidant system and UPR in the outcome of coronavirus infection.

8.
Front Cell Neurosci ; 16: 905218, 2022.
Article in English | MEDLINE | ID: covidwho-1974665

ABSTRACT

We are living in a terrifying pandemic caused by Sars-CoV-2, in which patients with diabetes mellitus have, from the beginning, been identified as having a high risk of hospitalization and mortality. This viral disease is not limited to the respiratory system, but also affects, among other organs, the central nervous system. Furthermore, we already know that individuals with diabetes mellitus exhibit signs of astrocyte dysfunction and are more likely to develop cognitive deficits and even dementia. It is now being realized that COVID-19 incurs long-term effects and that those infected can develop several neurological and psychiatric manifestations. As this virus seriously compromises cell metabolism by triggering several mechanisms leading to the unfolded protein response (UPR), which involves endoplasmic reticulum Ca2+ depletion, we review here the basis involved in this response that are intimately associated with the development of neurodegenerative diseases. The discussion aims to highlight two aspects-the role of calcium-binding proteins and the role of astrocytes, glial cells that integrate energy metabolism with neurotransmission and with neuroinflammation. Among the proteins discussed are calpain, calcineurin, and sorcin. These proteins are emphasized as markers of the UPR and are potential therapeutic targets. Finally, we discuss the role of drugs widely prescribed to patients with diabetes mellitus, such as statins, metformin, and calcium channel blockers. The review assesses potential neuroprotection mechanisms, focusing on the UPR and the restoration of reticular Ca2+ homeostasis, based on both clinical and experimental data.

9.
Neurochem Res ; 2022 Aug 03.
Article in English | MEDLINE | ID: covidwho-1971778

ABSTRACT

COVID-19, initially regarded as specific lung disease, exhibits an extremely broad spectrum of symptoms. Extrapulmonary manifestations of the disease also include important neuropsychiatric symptoms with atypical characteristics. Are these disturbances linked to stress accompanying every systemic infection, or are due to specific neurobiological changes associated with COVID-19? Evidence accumulated so far indicates that the pathophysiology of COVID-19 is characterized by systemic inflammation, hypoxia resulting from respiratory failure, and neuroinflammation (either due to viral neurotropism or in response to cytokine storm), all affecting the brain. It is reasonable to hypothesize that all these events may initiate or worsen psychiatric and cognitive disorders. Damage to the brain triggers a specific type of reactive response mounted by neuroglia cells, in particular by astrocytes which are the homeostatic cell par excellence. Astrocytes undergo complex morphological, biochemical, and functional remodeling aimed at mobilizing the regenerative potential of the central nervous system. If the brain is not directly damaged, resolution of systemic pathology usually results in restoration of the physiological homeostatic status of neuroglial cells. The completeness and dynamics of this process in pathological conditions remain largely unknown. In a subset of patients, glial cells could fail to recover after infection thus promoting the onset and progression of COVID-19-related neuropsychiatric diseases. There is evidence from post-mortem examinations of the brains of COVID-19 patients of alterations in both astrocytes and microglia. In conclusion, COVID-19 activates a huge reactive response of glial cells, that physiologically act as the main controller of the inflammatory, protective and regenerative events. However, in some patients the restoration of glial physiological state does not occur, thus compromising glial function and ultimately resulting in homeostatic failure underlying a set of specific neuropsychiatric symptoms related to COVID-19.

10.
Proc Natl Acad Sci U S A ; 119(30): e2122236119, 2022 07 26.
Article in English | MEDLINE | ID: covidwho-1947759

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) readily infects a variety of cell types impacting the function of vital organ systems, with particularly severe impact on respiratory function. Neurological symptoms, which range in severity, accompany as many as one-third of COVID-19 cases, indicating a potential vulnerability of neural cell types. To assess whether human cortical cells can be directly infected by SARS-CoV-2, we utilized stem-cell-derived cortical organoids as well as primary human cortical tissue, both from developmental and adult stages. We find significant and predominant infection in cortical astrocytes in both primary tissue and organoid cultures, with minimal infection of other cortical populations. Infected and bystander astrocytes have a corresponding increase in inflammatory gene expression, reactivity characteristics, increased cytokine and growth factor signaling, and cellular stress. Although human cortical cells, particularly astrocytes, have no observable ACE2 expression, we find high levels of coronavirus coreceptors in infected astrocytes, including CD147 and DPP4. Decreasing coreceptor abundance and activity reduces overall infection rate, and increasing expression is sufficient to promote infection. Thus, we find tropism of SARS-CoV-2 for human astrocytes resulting in inflammatory gliosis-type injury that is dependent on coronavirus coreceptors.


Subject(s)
Astrocytes , Cerebral Cortex , SARS-CoV-2 , Viral Tropism , Angiotensin-Converting Enzyme 2/metabolism , Astrocytes/enzymology , Astrocytes/virology , Cerebral Cortex/virology , Humans , Organoids/virology , Primary Cell Culture , SARS-CoV-2/physiology
11.
Italian Journal of Medicine ; 16(SUPPL 1):24, 2022.
Article in English | EMBASE | ID: covidwho-1912950

ABSTRACT

Case Report: A 62-year-old previously healthy male presented to the ED for confusion and single episode of epilepsy. A week earlier he received influenza vaccine. At admission, he had fever and agitation without meningeal irritation or neurological focal signs. Diagnostic tests including brain contrast-enhanced CT scan, MRI, nasopharyngeal SARS-CoV-2 swabs and lumbar puncture resulted unremarkable except for slightly increased CRP and increase of CSF and serum IL-6. On the 3°day, after hydration, steroids and antibiotic therapy, the patient presented a normal mental status, though amnesic for the previous 72 hours. A EEG on the 5°day and serum levels of IL-6 on the 8°day were normal. The patient was discharged at 10°day in good clinical conditions. Discussion: The acute onset after vaccination in absence of other documented etiologies, the overproduction of intrathecal neuroinflammatory mediators, the downward trend of cytokines and the prompt recovery after corticosteroid therapy, seem the typical picture of a brain dysfunction associated to cytokine storm. Recently, a unifying definition of cytokine storm-associated encephalopathy (CySE) was proposed. CySE origins from the massive release of cytokines promoting blood-brain barrier disruption and microglia/ astrocyte activation which support neuroinflammation in a synergistic act. Conclusions: We documented the first hyperacute reversible encephalopathy following influenza vaccination, suggesting cytokine storm as its causative mechanism, and highlighting the need to deepen our knowledge on this immune-mediated phenomenon.

12.
Journal of Urology ; 207(SUPPL 5):e415, 2022.
Article in English | EMBASE | ID: covidwho-1886501

ABSTRACT

INTRODUCTION AND OBJECTIVE: Neurodegenerative diseases, such as multiple sclerosis (MS), often lead to the development of neurogenic lower urinary tract symptoms (LUTS). We previously characterized neurogenic bladder dysfunction in a mouse model of MS induced by a coronavirus, mouse hepatitis virus (MHV). The objective of this study was to identify genes and pathways linking neuroinflammation in the central nervous system with urinary bladder dysfunction to enhance our understanding of the mechanisms underlying LUTS in demyelinating diseases. METHODS: Adult C57BL/6 male mice (N=12) received either an intracranial injection of MHV (6,000 PFU) or sterile saline (control). The lumbosacral (L6-S2) spinal cord (SC) segments and urinary bladders were collected during acute infection stage (week 1) and at the first peak of demyelination (week 4) after inoculation with the virus. Total RNA was isolated and analyzed using Nanostring nCounter Neuroinflammation panel. The expression levels of 770 genes associated with neuroinflammation were assessed and compared between the specimens. RESULTS: Transcriptome analysis of SC specimens confirmed a significantly increased expression of 132 genes in MHV mice (tens to hundreds fold change) involved in the regulation of astrocyte, microglia and oligodendrocyte functions, neuroinflammation and immune responses. Out of 132 genes up-regulated in the SC, only 2 genes (siglec1, 46-fold in the SC, 2.6-fold at 1 week and 1.8-fold at 4 weeks in the bladder;and zbp1, 568-fold in the SC, 2.8-fold at 1 week and 2.2-fold at 4 weeks in the bladder) were up-regulated in the urinary bladders of MHV-infected mice. Additionally, two genes were significantly up-regulated (ttr, 2.2-fold at 1week and 1.7-fold at 4 weeks;and ms4a4a, 2.3-fold at 1week and 1.6-fold at 4 weeks), and two were down-regulated (asb2, -1.8-fold at 1 week and -1.6-fold at 4 weeks, and myct1, -1.7-fold at 1week and -1.6-fold at 4 weeks) exclusively in the urinary bladders of MHV mice. CONCLUSIONS: Two genes, siglec1 (encodes type 1 transmembrane protein, expressed in microglia and macrophages, promotes neuroinflammation) and zbp1 (encodes a Z-DNA binding protein, plays role in the innate immune response) link the development of neuroinflammation in the central nervous system with neurogenic changes in the urinary bladders of MHV-infected mice. Further research is needed to establish a functional relationship between expression of these genes and neurogenic LUTS.

13.
Int Immunopharmacol ; 109: 108903, 2022 Aug.
Article in English | MEDLINE | ID: covidwho-1885844

ABSTRACT

With the widespread use of volatile anesthetic agents in the prolonged sedation for COVID-19 pneumonia and ARDS, there is an urgent need to investigate the effects and treatments of lengthy low-concentration inhaled anesthetics exposure on cognitive function in adults. Previous studies showed that general anesthetics dose- and exposure length-dependently induced neuroinflammatory response and cognitive decline in neonatal and aging animals. The anti-diabetes drug metformin has anti-neuroinflammation effects by modulating microglial polarization and inhibiting astrocyte activation. In this study, we demonstrated that the inhalation of 1.3% isoflurane (a sub-minimal alveolar concentration, sub-MAC) for 6 h impaired recognition of novel objects from Day 1 to Day3 in adult mice. Prolonged sub-MAC isoflurane exposure also triggered typically reactive microglia and A1-like astrocytes in the hippocampus of adult mice on Day 3 after anesthesia. In addition, prolonged isoflurane inhalation switched microglia into a proinflammatory M1 phenotype characterized by elevated CD68 and iNOS as well as decreased arginase-1 and IL-10. Metformin pretreatment before anesthesia enhanced cognitive performance in the novel object test. The positive cellular modifications promoted by metformin pretreatment included the inhibition of reactive microglia and A1-like astrocytes and the polarization of microglia into M2 phenotype in the hippocampus of adult mice. In conclusion, prolonged sub-MAC isoflurane exposure triggered significant hippocampal neuroinflammation and cognitive decline in adult mice which can be alleviated by metformin pretreatment via inhibiting reactive microglia and A1-like astrocytes and promoting microglia polarization toward anti-inflammatory phenotype in the hippocampus.


Subject(s)
Anesthetics , COVID-19 , Cognitive Dysfunction , Isoflurane , Metformin , Animals , Cognitive Dysfunction/chemically induced , Cognitive Dysfunction/drug therapy , Isoflurane/pharmacology , Isoflurane/therapeutic use , Metformin/pharmacology , Metformin/therapeutic use , Mice , Microglia , Neuroinflammatory Diseases
14.
Topics in Antiviral Medicine ; 30(1 SUPPL):64, 2022.
Article in English | EMBASE | ID: covidwho-1880463

ABSTRACT

Background: SARS-CoV-2 primarily infects the lung but may also damage other organs including the brain, heart, kidney, and intestine. Central nervous system (CNS) disorders include loss of smell and taste, headache, delirium, acute psychosis, seizures, and stroke. Pathological loss of gray matter occurs in SARS-CoV-2 infection but it is unclear whether this is due to direct viral infection, indirect effects associated with systemic inflammation, or both. Methods: We used iPSC-derived brain organoids and primary human astrocytes from cerebral cortex to study direct SARS-CoV-2 infection, as confirmed by Spike and Nucleocapsid immunostaining and RT-qPCR. siRNAs, blocking antibodies, and small molecule inhibitors were used to assess SARS-CoV-2 receptor candidates. Bulk RNA-seq, DNA methylation seq, and Nanostring GeoMx digital spatial profiling were utilized to identify virus-induced changes in host gene expression. Results: Astrocytes were robustly infected by SARS-CoV-2 in brain organoids while neurons and neuroprogenitor cells supported only low-level infection. Based on siRNA knockdowns, Neuropilin-1, not ACE2, functioned as the primary receptor for SARS-CoV-2 in astrocytes. The endolysosomal two-pore channel protein, TPC, also facilitated infection likely through its regulatory effects on endocytosis. Other alternative receptors, including the AXL tyrosine kinase, CD147, and dipeptidyl protease 4 (DPP4), did not function as SARS-CoV-2 receptors in astrocytes. SARS-CoV-2 infection dynamically induced type I, II, and III interferons, and genes involved in Toll-like receptor signaling, MDA5 and RIG-I sensing of double-stranded RNA, and production of inflammatory cytokines. Genes activating apoptosis were also increased. Down-regulated genes included those involved in water, ion and lipid transport, synaptic transmission, and formation of cell junctions. Epigenetic analyses revealed transcriptional changes related to DNA methylation states, particularly decreased DNA methylation in interferon-related genes. Long-term viral infection of brain organoids resulted in progressive neuronal degeneration and death. Conclusion: Our findings support a model where SARS-CoV-2 infection of astrocytes produces a panoply of changes in the expression of genes regulating innate immune signaling and inflammatory responses. Deregulation of these genes in astrocytes produces a microenvironment within the CNS that ultimately disrupts normal neuron function, promoting neuronal cell death and CNS deficits.

15.
Fluids Barriers CNS ; 19(1): 46, 2022 Jun 07.
Article in English | MEDLINE | ID: covidwho-1879246

ABSTRACT

BACKGROUND: Knowledge of the entry receptors responsible for SARS-CoV-2 is key to understand the neural transmission and pathogenesis of COVID-19 characterized by a neuroinflammatory scenario. Understanding the brain distribution of angiotensin converting enzyme 2 (ACE2), the primary entry receptor for SARS-CoV-2, remains mixed. Smoking has been shown as a risk factor for COVID-19 severity and it is not clear how smoking exacerbates the neural pathogenesis in smokers. METHODS: Immunohistochemistry, real-time PCR and western blot assays were used to systemically examine the spatial-, cell type- and isoform-specific expression of ACE2 in mouse brain and primary cultured brain cells. Experimental smoking exposure was conducted to evaluate the effect of smoking on brain expression. RESULTS: We observed ubiquitous expression of ACE2 but uneven brain distribution, with high expression in the cerebral microvasculature, medulla oblongata, hypothalamus, subventricular zones, and meninges around medulla oblongata and hypothalamus. Co-staining with cell type-specific markers demonstrates ACE2 is primarily expressed in astrocytes around the microvasculature, medulla oblongata, hypothalamus, ventricular and subventricular zones of cerebral ventricles, and subependymal zones in rhinoceles and rostral migratory streams, radial glial cells in the lateral ventricular zones, tanycytes in the third ventricle, epithelial cells and stroma in the cerebral choroid plexus, as well as cerebral pericytes, but rarely detected in neurons and cerebral endothelial cells. ACE2 expression in astrocytes is further confirmed in primary cultured cells. Furthermore, isoform-specific analysis shows astrocyte ACE2 has the peptidase domain responsible for SARS-CoV-2 entry, indicating astrocytes are indeed vulnerable to SARS-CoV-2 infection. Finally, our data show experimental tobacco smoking and electronic nicotine vaping exposure increase proinflammatory and/or immunomodulatory cytokine IL-1a, IL-6 and IL-5 without significantly affecting ACE2 expression in the brain, suggesting smoking may pre-condition a neuroinflammatory state in the brain. CONCLUSIONS: The present study demonstrates a spatial- and cell type-specific expression of ACE2 in the brain, which might help to understand the acute and lasting post-infection neuropsychological manifestations in COVID-19 patients. Our data highlights a potential role of astrocyte ACE2 in the neural transmission and pathogenesis of COVID-19. This also suggests a pre-conditioned neuroinflammatory and immunocompromised scenario might attribute to exacerbated COVID-19 severity in the smokers.


Subject(s)
COVID-19 , Vaping , Angiotensin-Converting Enzyme 2 , Animals , Astrocytes , Endothelial Cells , Humans , Mice , SARS-CoV-2 , Smoking/adverse effects , Synaptic Transmission , Tobacco Smoking
16.
Neurobiol Dis ; 168: 105715, 2022 06 15.
Article in English | MEDLINE | ID: covidwho-1763913

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic is responsible for 267 million infections and over 5 million deaths globally. COVID-19 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a single-stranded RNA beta-coronavirus, which causes a systemic inflammatory response, multi-organ damage, and respiratory failure requiring intubation in serious cases. SARS-CoV-2 can also trigger neurological conditions and syndromes, which can be long-lasting and potentially irreversible. Since COVID-19 infections continue to mount, the burden of SARS-CoV-2-induced neurologic sequalae will rise in parallel. Therefore, understanding the spectrum of neurological clinical presentations in SARS-CoV-2 is needed to manage COVID-19 patients, facilitate diagnosis, and expedite earlier treatment to improve outcomes. Furthermore, a deeper knowledge of the neurological SARS-CoV-2 pathomechanisms could uncover potential therapeutic targets to prevent or mitigate neurologic damage secondary to COVID-19 infection. Evidence indicates a multifaceted pathology involving viral neurotropism and direct neuroinvasion along with cytokine storm and neuroinflammation leading to nerve injury. Importantly, pathological processes in neural tissue are non-cell autonomous and occur through a concerted breakdown in neuron-glia homeostasis, spanning neuron axonal damage, astrogliosis, microgliosis, and impaired neuron-glia communication. A clearer mechanistic and molecular picture of neurological pathology in SARS-CoV-2 may lead to effective therapies that prevent or mitigate neural damage in patients contracting and developing severe COVID-19 infection.


Subject(s)
COVID-19 , COVID-19/complications , Disease Progression , Homeostasis , Humans , Neuroglia , Neurons , SARS-CoV-2
17.
J Neuroimmune Pharmacol ; 15(4): 584-627, 2020 12.
Article in English | MEDLINE | ID: covidwho-1384565

ABSTRACT

With the current national opioid crisis, it is critical to examine the mechanisms underlying pathophysiologic interactions between human immunodeficiency virus (HIV) and opioids in the central nervous system (CNS). Recent advances in experimental models, methodology, and our understanding of disease processes at the molecular and cellular levels reveal opioid-HIV interactions with increasing clarity. However, despite the substantial new insight, the unique impact of opioids on the severity, progression, and prognosis of neuroHIV and HIV-associated neurocognitive disorders (HAND) are not fully understood. In this review, we explore, in detail, what is currently known about mechanisms underlying opioid interactions with HIV, with emphasis on individual HIV-1-expressed gene products at the molecular, cellular and systems levels. Furthermore, we review preclinical and clinical studies with a focus on key considerations when addressing questions of whether opioid-HIV interactive pathogenesis results in unique structural or functional deficits not seen with either disease alone. These considerations include, understanding the combined consequences of HIV-1 genetic variants, host variants, and µ-opioid receptor (MOR) and HIV chemokine co-receptor interactions on the comorbidity. Lastly, we present topics that need to be considered in the future to better understand the unique contributions of opioids to the pathophysiology of neuroHIV. Graphical Abstract Blood-brain barrier and the neurovascular unit. With HIV and opiate co-exposure (represented below the dotted line), there is breakdown of tight junction proteins and increased leakage of paracellular compounds into the brain. Despite this, opiate exposure selectively increases the expression of some efflux transporters, thereby restricting brain penetration of specific drugs.


Subject(s)
AIDS Dementia Complex/complications , COVID-19 , HIV Infections/complications , Opioid Epidemic , Opioid-Related Disorders/epidemiology , HIV-1/immunology , Humans
18.
Front Cell Neurosci ; 15: 695899, 2021.
Article in English | MEDLINE | ID: covidwho-1295667

ABSTRACT

Extracellular vesicles (EVs) are small, membrane-bound vesicles released by cells as a means of intercellular communication. EVs transfer proteins, nucleic acids, and other biologically relevant molecules from one cell to another. In the context of viral infections, EVs can also contain viruses, viral proteins, and viral nucleic acids. While there is some evidence that the inclusion of viral components within EVs may be part of the host defense, much of the research in this field supports a pro-viral role for EVs. Packaging of viruses within EVs has repeatedly been shown to protect viruses from antibody neutralization while also allowing for their integration into cells otherwise impervious to the virus. EVs also bidirectionally cross the blood-brain barrier (BBB), providing a potential route for peripheral viruses to enter the brain while exiting EVs may serve as valuable biomarkers of neurological disease burden. Within the brain, EVs can alter glial activity, increase neuroinflammation, and induce neurotoxicity. The purpose of this mini-review is to summarize research related to viral manipulation of EV-mediated intercellular communication and how such manipulation may lead to infection of the central nervous system, chronic neuroinflammation, and neurodegeneration.

19.
Neurochem Int ; 148: 105101, 2021 09.
Article in English | MEDLINE | ID: covidwho-1271730

ABSTRACT

Central nervous system (CNS) diseases are responsible for a large proportion of morbidity and mortality worldwide. CNS diseases caused by intrinsic and extrinsic stimuli stimulate the resident immune cells including microglia and astrocyte, resulting in neuroinflammation that exacerbates the progression of diseases. Recent evidence reveals the aberrant expression patterns of long non-coding RNAs (lncRNAs) in the damaged tissues following CNS diseases. It was also proposed that lncRNAs possessed immune-modulatory activities by directly or indirectly affecting various effector proteins including transcriptional factor, acetylase, protein kinase, phosphatase, etc. In addition, lncRNAs can form a sophisticated network by interacting with other molecules to regulate the expression or activation of downstream immune response pathways. However, the major roles of lncRNAs in CNS pathophysiologies are still elusive, especially in neuroinflammation. Herein, we tend to review some potential roles of lncRNAs in modulating neuroinflammation based on current evidence in various CNS diseases, in order to provide novel explanations for the initiation and progression of CNS diseases and help to establish therapeutic strategies targeting neuroinflammation.


Subject(s)
Central Nervous System Diseases/genetics , RNA, Long Noncoding/physiology , Animals , Central Nervous System Diseases/drug therapy , Central Nervous System Diseases/pathology , Humans , /pathology , RNA, Long Noncoding/genetics
20.
Front Cell Neurosci ; 15: 662578, 2021.
Article in English | MEDLINE | ID: covidwho-1175546

ABSTRACT

At the end of 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was discovered in China, causing a new coronavirus disease, termed COVID-19 by the WHO on February 11, 2020. At the time of this paper (January 31, 2021), more than 100 million cases have been recorded, which have claimed over 2 million lives worldwide. The most important clinical presentation of COVID-19 is severe pneumonia; however, many patients present various neurological symptoms, ranging from loss of olfaction, nausea, dizziness, and headache to encephalopathy and stroke, with a high prevalence of inflammatory central nervous system (CNS) syndromes. SARS-CoV-2 may also target the respiratory center in the brainstem and cause silent hypoxemia. However, the neurotropic mechanism(s) by which SARS-CoV-2 affects the CNS remain(s) unclear. In this paper, we first address the involvement of astrocytes in COVID-19 and then elucidate the present knowledge on SARS-CoV-2 as a neurotropic virus as well as several other neurotropic flaviviruses (with a particular emphasis on the West Nile virus, tick-borne encephalitis virus, and Zika virus) to highlight the neurotropic mechanisms that target astroglial cells in the CNS. These key homeostasis-providing cells in the CNS exhibit many functions that act as a favorable milieu for virus replication and possibly a favorable environment for SARS-CoV-2 as well. The role of astrocytes in COVID-19 pathology, related to aging and neurodegenerative disorders, and environmental factors, is discussed. Understanding these mechanisms is key to better understanding the pathophysiology of COVID-19 and for developing new strategies to mitigate the neurotropic manifestations of COVID-19.

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