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COVID-19 is a severe acute respiratory syndrome caused by a novel coronavirus, SARS-CoV- 2.COVID-19 is now a pandemic, and is not yet fully under control.As the surface spike protein (S) mediates the recognition between the virus and cell membrane and the process of cell entry, it plays an important role in the course of disease transmission.The study on the S protein not only elucidates the structure and function of virus-related proteins and explains their cellular entry mechanism, but also provides valuable information for the prevention, diagnosis and treatment of COVII)-19.Concentrated on the S protein of SARS-CoV-2, this review covers four aspects: (1 ) The structure of the S protein and its binding with angiotensin converting enzyme II (ACE2) , the specific receptor of SARS-CoV-2, is introduced in detail.Compared with SARS-CoV, the receptor binding domain (RBD) of the SARS-CoV- 2 S protein has a higher affinity with ACE2, while the affinity of the entire S protein is on the contrary.(2) Currently, the cell entry mechanism of SARS-CoV-2 meditated by the S protein is proposed to include endosomal and non-endosomal pathways.With the recognition and binding between the S protein and ACE2 or after cell entry, transmembrane protease serine 2(TMPRSS2) , lysosomal cathepsin or the furin enzyme can cleave S protein at S1/S2 cleavage site, facilitating the fusion between the virus and target membrane.(3) For the progress in SARS-CoV-2 S protein antibodies, a collection of significant antibodies are introduced and compared in the fields of the target, source and type.(4) Mechanisms of therapeutic treatments for SARS-CoV-2 varied.Though the antibody and medicine treatments related to the SARS-CoV-2 S protein are of high specificity and great efficacy, the mechanism, safety, applicability and stability of some agents are still unclear and need further assessment.Therefore, to curb the pandemic, researchers in all fields need more cooperation in the development of SARS-CoV-2 antibodies and medicines to face the great challenge.Copyright © Palaeogeography (Chinese Edition).All right reserved.
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Objective: Although the neurological and olfactory symptoms of coronavirus disease 2019 have been identified, the neurotropic properties of the causative virus, severe acute respiratory syndrome-associated coronavirus 2 (SARS-CoV-2), remain unknown. We sought to identify the susceptible cell types and potential routes of SARS-CoV-2 entry into the central nervous system, olfactory system, and respiratory system. Method(s): We collected single-cell RNA data from normal brain and nasal epithelium specimens, along with bronchial, tracheal, and lung specimens in public datasets. The susceptible cell types that express SARS-CoV-2 entry genes were identified using single-cell RNA sequencing and the expression of the key genes at protein levels was verified by immunohistochemistry. We compared the coexpression patterns of the entry receptor angiotensin-converting enzyme 2 (ACE2) and the spike protein priming enzyme transmembrane serine protease (TMPRSS)/cathepsin L among the specimens. Result(s): The SARS-CoV-2 entry receptor ACE2 and the spike protein priming enzyme TMPRSS/cathepsin L were coexpressed by pericytes in brain tissue;this coexpression was confirmed by immunohistochemistry. In the nasal epithelium, ciliated cells and sustentacular cells exhibited strong coexpression of ACE2 and TMPRSS. Neurons and glia in the brain and nasal epithelium did not exhibit coexpression of ACE2 and TMPRSS. However, coexpression was present in ciliated cells, vascular smooth muscle cells, and fibroblasts in tracheal tissue;ciliated cells and goblet cells in bronchial tissue;and alveolar epithelium type 1 cells, AT2 cells, and ciliated cells in lung tissue. Conclusion(s): Neurological symptoms in patients with coronavirus disease 2019 could be associated with SARS-CoV-2 invasion across the blood-brain barrier via pericytes. Additionally, SARS-CoV-2-induced olfactory disorders could be the result of localized cell damage in the nasal epithelium.Copyright © Wolters Kluwer Health, Inc. All rights reserved.
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Cumulative data regardingCOVID-19 infection during pregnancy have demonstrated the ability of SARS-CoV-2 to infect the placenta. However, the mechanisms of SARS-CoV-2 placental viral entry are yet to be defined. SARS-CoV-2 infects cells by binding to the ACE2 receptor. However, SARS-CoV-2 cell entry also requires co-localization of spike protein cleavage by the serine protease TMPRSS2. However, the co-expression of ACE2 and TMPRSS2 in placental cells is debated, raising the question of whether potential non-canonical molecular mechanismsmay be involved in SARS-CoV-2 placental cells' viral entry. Although published data regarding the ability of the SARS-CoV- 2 to infect the fetus are contradicting, the placenta appears to be an immunological barrier to active SARS-CoV-2 infection and vertical transmission;however, the mechanism is unclear. Our experiments demonstrated the ability of the SARS-CoV-2 virus to directly infect the placenta and induce transcriptomic responses in COVID-positive mothers. These transcriptomic responses were characterized by differential expression of specific mRNAs and miRNAs associated with SARS-CoV-2 infection, with induction of specific placental miRNAs that can inhibit viral replication. Failure in such mechanisms may be associated with vertical transmission. Since the start of the COVID-19 pandemic, the COVID-19 mRNA vaccines have been widely used to reduce the morbidity and mortality of SARS-CoV-2 infection. Historically, non-live vaccines have not caused any harm to pregnant mothers;however, it is unclear whether our current understanding of the effects of non-live vaccines serves as a reliable precedent owing to the novel technology used to create these mRNA vaccines. Since there are no definitive data on the possible biodistribution of mRNA vaccines to the placenta, the likelihood of vaccine mRNA reaching the fetus remains uncertain. Little has been reported on the tissue localization of the lipid nanoparticles (LNPs) after intramuscular (IM) administration of the mRNA vaccine. The biodistribution of LNPs containing the mRNA vaccine has been investigated in animal models but not humans. In the murine model, the vaccine LNPs were rapidly disseminated to several organs, including the heart, liver, kidney, lung, and spleen, following IM administration. However, no traditional pharmacokinetic or biodistribution studies have been performed with the mRNA vaccines, including possible biodistribution to breast milk or the placenta.
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One of the symptoms of a new coronavirus infection (COVID-19) is a complete or partial violation of the sense of smell. The aim of the work is to analyze the published results of scientific research on the mechanisms of olfactory impairment in COVID-19. Material and methods. Research was conducted for publications in Pubmed on the problem of olfactory impairment in COVID-19 using terms indexed by MeSH. The systematic review was compiled in accordance with the checklist Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA). Results. Publication's analysis has shown that the existing ideas about conductive anosmia are insufficient to explain the causes of olfactory impairment caused by SARS-CoV-2. It has been established that ACE2 and TMPRSS2 receptors located on the surface of target cells are necessary for the penetration of a new coronavirus. It is known that these receptors are mainly located on the cells of the olfactory epithelium. The main hypothesis of olfactory impairment in COVID-19 is that anosmia/hyposmia is caused by damage not to neuronal cells (as previously assumed), but to the olfactory epithelium. There is no confirmation of the point of view about the damage of SARS-CoV-2 olfactory bulbs and olfactory neurons, since they do not express receptor proteins for the virus on their surface.Copyright © 2022 by the authors.
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Introduction: Multiple meta-analyses have shown that over 15% patients with COVID-19 have at least one gastrointestinal complaint, most commonly diarrhea. The effects on the gastrointestinal system are thought to be mediated by the high expression of angiotensin-converting enzyme 2 (ACE2) and cellular serine proteases (TMPRSS2) in enterocytes, which cause altered intestinal permeability. The purpose of this study was to determine the incidence of diarrhea as it relates to COVID-19 infection and to determine if having concomitant diarrhea had a significant impact on disease course. Method(s): A retrospective chart review of 164,730 patients in a hospital system who were older than 18 years of age and had a positive SARS-CoV-2 test from March 2020 to February 2022 was completed. Diarrhea was determined using ICD code or patient's symptoms. Patients with confounding variables such as IBD, IBS, Celiac, Clostridium difficile, and pancreatic insufficiency were excluded. Demographic clinical characteristics and outcomes, including inpatient admission and mortality, were compared in patients with and without diarrhea. The Mann-Whitney test and Fisher's exact or Chi-square test was used for continuous and categorical variables respectively and multivariate logistic regression was used to evaluate for significant differences in disease outcome between the two groups. (Table) Results: Of the 164,730 patients included, 14,648 (8.89%) had diarrhea at the time of SARS-CoV-2. 6,748/33,464 (20.16%) of inpatient admissions were associated with diarrhea. On multivariate analysis, diarrhea was an independent risk factor for inpatient hospitalization (OR 2.39, CI 95% 2.28-2.51, P, 0.001) and inpatient mortality (OR 1.15, CI 96% 1.06-1.26, P= 0.001) after controlling for age, gender, race, comorbidities that could impact patient outcome, use of immunomodulators and outpatient antibiotics. Conclusion(s): These findings show that, even with controlling for comorbidities with COVID-19, diarrhea was an independent factor for predicting inpatient mortality and inpatient admission in general. Patients who had diarrhea and COVID-19 were sicker, having more comorbid conditions than those without diarrhea in our cohort. Attention should be given to not only respiratory complaints of COVID-19, but also gastrointestinal complaints, as they are an indicator of poor prognosis and mortality.
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Neurological complications of COVID-19 contribute significantly to mortality in the intensive care unit (ICU). Preventive therapy, though discussed in literature, is limited for COVID-19 neurological manifestations and treatment algorithms continue to rely on evidence from previous pandemics. Thus, in this chapter we evaluate current in vitro, in vitro, histopathological studies to ascertain the most likely mechanisms of SARS-CoV-2 central nervous system entry. From this understanding, we determine probable mechanisms for neurological compilations observed in COVID-19 as relevant to the clinician. SARS-CoV-2 infection of nasal epithelium and the respiratory tract may allow for a systemic inflammatory response that results in neuroinflammation. While most neurological complications are inflammatory in etiology, rarely, SARS-CoV-2 may enter into the central nervous system and mediate neuronal damage. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.
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Coronavirus disease 2019 (Covid 19) is caused by the severe acute respiratory syndrome coronavirus-2 (SARS CoV 2) and causes lymphopenia, immunosuppression, inefficient T and B cell immunity, cytokine storm, and destructive tissue inflammation. Since COVID 19 is a multi-system disease predominantly affecting the lungs, there is doubt on whether chronic lung diseases place patients at higher risk and SARS CoV2 leads to asthma exacerbation. None of the studies have reported asthma or recurrent wheezing as a comorbidity or risk factor for Covid 19 in children up to now. Notably, further studies are needed to explore the relationship between Covid 19 and asthma to improve clinical practice and decrease morbidity and mortality.Copyright © 2020 Bilimsel Tip Yayinevi. All rights reserved.
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Background: We previously screened 10 human lung and upper airway cell lines expressing variable levels of endogenous ACE2/TMPRSS2. We found that H522 human lung adenocarcinoma cells supported SARS-CoV-2 replication independent of ACE2, whereas the ACE2 positive cell lines were not permissive to infection. Type I/III interferons (IFNs) potently restrict SARS-CoV-2 replication through the actions of hundreds of interferon-stimulated genes (ISGs) that are upregulated upon IFN signaling. Here we report that a number of ACE2 positive airway cell lines are unable to support SARS-CoV-2 replication due to basal activation of the cGAS-STING DNA sensing pathway and subsequent upregulation of IFNs and ISGs which restrict SARS-CoV-2 replication. Method(s): SARS-CoV-2 WT strain 2019-nCoV/USA-WA1/2020 viral replication was detected through analysis of cell associated RNA. RNA sequencing was used to study the basal level of genes in the type-I IFN pathway in the 10 cell lines, which was further validated by western blotting and qRT-PCR. A panel of 5 cell lines, with varying expression levels of ACE2 and TMPRSS2, were pre-treated with Ruxolitinib, a JAK1/2 inhibitor. A siRNA-mediated screen was used to determine the molecular basis of basally high expression of ISGs in cell lines. CRISPR knockout of IFN-alpha receptor and cGAS-STING pathway components was conducted in parallel Results: Here we show that higher basal levels of IFN pathway activity underlie the inability of ACE2+ cell lines to support virus replication. Importantly, this IFN-induced block can be overcome by chemical inhibition and genetic disruption of the IFN signaling pathway or by ACE2 overexpression, suggesting that one or more saturable ISGs underlie the lack of permissivity of these cells. Ruxolitinib treatment increased SARS-CoV-2 RNA levels by nearly 3 logs in OE21 and SCC25. Furthermore, the baseline activation of the STING-cGAS pathway accounts for the high ISG levels and genetic disruption of the cGAS-STING pathway enhances levels by nearly 2 and 3 logs of virus replication in the two separate ACE2+ cell line models respectively. Conclusion(s): Our findings demonstrate that cGAS-STING-dependent activation of IFN-mediated innate immunity underlies the inability of ACE2+ airway cell lines to support SARS-CoV-2 replication. Our study highlights that in addition to ACE2, basal activation of cGAS-STING pathway, IFNs and ISGs may play a key role in defining SARS-CoV-2 cellular tropism and may explain the complex SARS-CoV- 2 pathogenesis in vivo.
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Background and Objectives: * The spike (S) protein of SARS-CoV-2 virus binds to the host cell receptor which facilitates the virus entry. This interaction is primed by host cell proteases like furin and TMPRSS2 acting at S1/S2 and S2' cleavage sites, respectively. * Both the cleavage sites have Serine and Proline residues conversed in all the coronaviruses. It has been speculated that mutations at these conserved residues may provide a gain-offunction, easing the SARS-CoV-2 entry into the host cell and cellto- cell spread, thus modulating the virulence and pathogenicity. * Unravelling the effects of these conserved residues in the S protein cleavage site in virus entry and transmission might facilitate development of novel therapeutics. Material(s) and Method(s): * This study employed a lentivirus based pseudovirus (PSV) system, where P and S residues at S1/S2 site of Spike gene, present in an expression vector, were mutated to Alanine (Fig A). * We then assessed the expression of the SARS-CoV-2-S variants in HEK293T cells and tested the infectivity and fusogenicity of mutant PSV and spike, respectively in the presence or absence of S1/S2 and S2' protease inhibitors. Results and Conclusion(s): * Conserved Serine residue mutation (S2SA) at S2' cleavage site resulted in complete loss of spike cleavage by furin and cathepsins (Fig B). * TMPRSS2 protease treatment was not able to rescue loss of spike cleavage and fusogenicity (Fig C & D). * S2SA mutant showed no significant response against E-64d and TMPRSS2 inhibitor. * Serine at S2' site in spike protein provides an ideal site to be further evaluated for the therapeutic purpose against SARS-CoV- 2.
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Introduction/Aim: The spike protein of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus enables it to recognise and bind host receptors. These dynamics have been modelled in various cell types and immortalised lines, but rarely in primary airway epithelial cells (AEC), and especially not in children. Therefore, this study on AEC recapitulated earlier work testing the hypothesis that exposure to the spike protein would induce airway immune responses in airway cells of young children. Method(s): Primary AEC monolayer cultures from healthy children (n = 5, <10 years old, males = 5) were exposed to the spike protein S1 subunit (0.01, 1, and 10 mug/mL) over 48 h. Induced inflammatory cytokines, interleukin (IL) 6 and IL8, and viral-associated chemokines, CCL5 and CXCL10 were measured via ELISA. Basal receptor gene expression (ACE2 and TMPRSS2) was measured in monolayer (n = 5) and terminally differentiated (air-liquid interface [ALI];n = 5) cell models as well as in ex-vivo cells obtained directly from nasal brushings (n = 71). Generalised linear modelling, accounting for individual variability, identified any statistical difference (p < 0.05). Result(s): Exposure to the spike protein resulted in no increase in IL6 and IL8 production, however a significant (p < 0.05) decrease was observed at the highest dose tested (10 mug/mL). CXCL10 was only significantly induced at the highest dose (10 mug/mL) whereas CCL5 was not induced. When compared to ex-vivo samples, baseline expression of ACE2 and TMPRSS2 was significantly lower in monolayer cultures (~57- and ~4- fold respectively, p < 0.05), whereas ALI cultures had similar expression levels. Conclusion(s): The use of recombinant spike protein and monolayer cultures appears to not accurately model SARS-CoV-2 spike protein-host interactions. The lack of inflammatory responses may be attributed to the lower receptor gene expression in monolayer cultures. Future studies should utilise live virus and ALI cultures as a more biologically relevant model to study virus-host interactions.
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INTRODUCTION: Glioblastoma (GBM) is the most common and deadliest primary brain tumor, characterized by chemoradiation resistance and an immunosuppressive tumor microenvironment (TME). SARS-CoV-2, the COVID-19 virus, produces a significant proinflammatory response and a spectrum of clinical presentations after central nervous system infection. METHOD(S): Patient-derived GBM tissue, primary cell lines, and organoids were analyzed with immunohistochemistry and pixel-line intensity quantification. Data from tumor-bulk and single-cell transcriptomics served to describe the cell-specific expression of SARS-CoV-2 receptors in GBM and its association with the immune TME phenotype. Normal brain and iPSC-derived organoids served as controls. RESULT(S): We demonstrate that patient-derivedGBMtissue and cell cultures express SARS-CoV2 entry factors such as ACE2, TMPRSS2, and NRP1. NRP1 expression was higher in GBM than in normal brains (p<0.05), where it plays a crucial role in SARS-CoV-2 infection. NRP1 was expressed in a cell-type and phenotype-specific manner and correlated with TME infiltration of immunosuppressive cells: M2 macrophages (r = 0.229), regulatory T cells (r = 0.459), NK cells (r = -0.346), and endothelial cells (r = 0.288) (p < 0.05). Furthermore, gene ontology enrichment analysis showed that leukocyte migration and chemotaxis are among the top 5 biological functions mediated by NRP1 (p < 0.05). We found our GBM organoids recapitulate tumoral expression of SARSCoV- 2 entry factors, which varies based on distance from surface as surrogate of TME oxygenation (p < 0.05). CONCLUSION(S): GBM cancer cells and immune TME cells express SARS-CoV-2 entry factors. Glioblastoma organoids recapitulate this expression and allow for currently undergoing studies analyzing the effect of SARS-CoV-2 infection in GBM. Our findings suggest that SARSCoV- 2 could potentially target GBM, opening the door to future studies evaluating SARS-CoV-2-driven immune modulation.
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SARS-CoV-2 has a predilection for cell groups that are rich in ACE2 and TMPRSS2 receptors, which are distributed throughout the human body, which means that, in addition to the primary site of contagion or primary infection, which is the respiratory system, the virus tends to spread by different mechanisms, affecting practically all the known organs, apparatuses and systems, with which its tropism becomes extensive, being able to condition diverse pictures together with the respiratory one.Copyright © 2023 Comunicaciones Cientificas Mexicanas S.A. de C.V.. All rights reserved.
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SARS-CoV-2, the coronavirus that causes the disease COVID- 19, was identified over three years ago, yet current small molecule therapies have limited usefulness and resistance to therapies and vaccines is inevitable. Ultra high-throughput screening (uHTS) assays for novel and repurposed inhibitors of a protein-protein interaction in the viral life cycle could be used to screen a vast number of compounds with a specific target of action. In particular, the interaction between viral SPIKE protein and human TMPRSS2 is an understudied, yet critical step in viral entry. Thus, we aim to create uHTS assays to rapidly and affordably identify inhibitors of the TMPRSS2 and SPIKE interaction for further biochemical studies and therapeutic development for SARS-CoV-2.We first sought to create a Time Resolved-Forster/Fluorescence Energy Transfer (TR-FRET) assay which uses lysates of cells with overexpressed SPIKE and TMPRSS2 and fluorescently labeled antibodies to detect interactions between these proteins. Initially, we developed and optimized this TR-FRET assay in a 384-well plate then miniaturized to a 1536-well plate. We conducted a pilot screen of compounds with known biological activity to test this assay's screening capabilities. To further narrow the hits from this TR-FRET screen, we developed an orthogonal uHTS Nanoluciferase Binary Technology (NanoBiT) assay to detect the interaction between tagged SPIKE and TMPRSS2 in live cells.With these two assays in hand, we expanded our TR-FRET screen to over 100 000 compounds and identified several that were also positive in the orthogonal NanoBiT assay. Four of these compounds were found to potentially interact with either SPIKE or TMPRSS2 from thermal shift experiments, providing support for their action as SPIKE and TMPRSS2 interaction inhibitors. Thus, we have developed TR-FRET and NanoBiT orthogonal uHTS assays which have allowed for the discovery of several possible repurposed and novel inhibitors of the SPIKE/ TMPRSS2 interaction. These uHTS assays can be employed as a model for future drug discovery efforts and the compounds identified may be used as exciting starting points for development of inhibitors of SARS-CoV-2. This research was supported in part by The Emory School of Medicine COVID Catalyst-I3 award, the NCI Emory Lung Cancer SPORE (SR, HF;P50CA217691) Career Enhancement Program (AI, P50CA217691), Emory initiative on Biological Discovery through Chemical Innovation (AI) and R01AI167356 (SS).Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.
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Background: Air-liquid interface (ALI) and organoid culture are key techniques for differentiating human airway epithelial cells (HAECs). The efficiency and robustness of these assays often depends on the quality of primary-isolated cells, but primary cell isolation workflows, with which the user controls the choice of isolation method, cell culture medium, and culture format, may reduce reproducibility. Therefore, an optimized, standardized workflow can enhance and support isolation of epithelial cells from diseased donors with potentially rare cystic fibrosis (CF) mutations or particularly sensitive cell populations. We have developed a standardized workflow for isolation and culture of freshly derived airway epithelial cells. Method(s): Briefly, HAECs isolated from primary tissue were expanded in PneumaCult-Ex Plus Medium for 1 week and then seeded into Corning Transwell inserts and expanded until confluency. The cells were then differentiated in PneumaCult-ALI Medium for at least 4 weeks. To assess differentiation efficiency in ALI culture, the cells were immunostained to detect Muc5AC, acetylated tubulin, and ZO-1 to identify goblet cells, ciliated cells, and apical tight junctions, respectively, aswell as SARS-CoV-2 cell entry targets angiotensin-converting enzyme 2 and transmembrane serine protease 2. Ion transport and barrier function of the ALI culturesand response to CF transmembrane conductance regulator (CFTR) correctors were also measured. In addition, freshly derived HAECs were seeded into Corning Matrigel domes in the presence of PneumaCult Airway Organoid Seeding Medium. Oneweek later, the mediumwas changed to PneumaCult Airway Organoid Differentiation Medium and maintained for an additional 3 weeks to promote cell differentiation. These airway organoids were then treated with CFTR corrector VX-809 for 24 hours, followed by 6-hour treatment with amiloride, forskolin, and genistein to induce organoid swelling. Result(s): Our results demonstrate that ALI cultures derived from CF donors displayed partial rescue of CFTR across multiple passages after treatment with VX-809. Airway organoids were found to express functional CFTR, as evidenced by forskolin treatment, which induced a 64 +/- 14% (n = 1 donor) greater organoid area than in vehicle control-treated airway organoids. Airway organoids derived from CF donors displayed a loss of forskolininduced swelling, which could be partially re-established with VX-809 treatment (29 +/- 9%, n = 3). Conclusion(s): In summary, the PneumaCult workflow supports robust, efficient culture of primary-airway epithelial cells that can be used as physiologically relevant models suitable for CF research, CFTR corrector screening, and studying airway biology.Copyright © 2022, European Cystic Fibrosis Society. All rights reserved
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CoViD-19 is the current pandemic caused by the Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2). Infection by SARS-CoV-2 occurs via the binding of its S protein to the angiotensin-converting enzyme-2 receptor (ACE2-R). S binding to ACE2-R leads to a drop in ACE2, a homolog of angiotensin converting enzyme (ACE). In the central nervous system (CNS), ACE mediates neuroinflammation, neurodegeneration and neurotoxicity responsible for several CNS disorders. ACE2 counteracts the damaging effects of ACE on CNS neurons. SARS-CoV-2 can directly access the CNS via the circulation or via cranial nerve I and the olfactory bulb. Inactivation of ACE2 following binding of SARS-CoV-2 S protein to ACE2-R in situ might blunt ACE2-moderating effects upon ACE CNS neurotoxicity and neurodegeneration. Here, we propose a neurobiological mechanism directly involving SARS-CoV-2 binding to ACE2-R in the etiology of putative Neuro-CoViD-19.
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During the treatment of critically ill COVID-19 patients it has been revealed that the neutralizing monoclonal antibodies against 2019-nCoV have the advantages of high specificity, high purity, and can be prepared in a large scale, which are expected to be a effective preparation for clinical use. This article introduces the way of 2019-nCoV invasion into the host cells, the major variants of novel coronavirus, and the mechanism of action of anti-2019-nCoV monoclonal antibodies, as well as the progress of research and development of their preparation in major pharmaceutical companies, to provide reference for scientific research and clinical application.Copyright © Chinese Journal of Clinical Infectious Diseases.All rights reserved.
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Coronavirus disease (COVID-19) is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). SARS-CoV-2 RNA has been found in the human testis on occasion, but subgenomic SARS-CoV-2 and infectious SARS-CoV-2 virions have not been found. There is no direct evidence of SARS-CoV-2 infection of testicular cells. To better understand this, it is necessary to determine whether SARS-CoV-2 receptors and proteases are present in testicular cells. To overcome this limitation, we focused on elucidating with immunohistochemistry the spatial distribution of the SARS-CoV-2 receptors angiotensin-converting enzyme 2 (ACE2) and cluster of differentiation 147 (CD147), as well as their viral spike protein priming proteases, transmembrane protease serine 2 (TMPRSS2) and cathepsin L (CTSL), required for viral fusion with host cells. At the protein level, human testicular tissue expressed both receptors and proteases studied. Both ACE2 and TMPRSS2 were found in interstitial cells (endothelium, Leydig, and myoid peritubular cells) and in the seminiferous epithelium (Sertoli cells, spermatogonia, spermatocytes, and spermatids). The presence of CD147 was observed in all cell types except endothelium and peritubular cells, while CTSL was exclusively observed in Leydig, peritubular, and Sertoli cells. These findings show that the ACE2 receptor and its protease TMPRSS2 are coexpressed in all testicular cells, as well as the CD147 receptor and its protease CTSL in Leydig and Sertoli cells, indicating that testicular SARS-CoV-2 infection cannot be ruled out without further investigation.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Male , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , COVID-19/metabolism , Angiotensin-Converting Enzyme 2/metabolism , Peptide Hydrolases/metabolism , Testis , RNA, Viral , Peptidyl-Dipeptidase A/genetics , Peptidyl-Dipeptidase A/metabolismABSTRACT
Background: SARS-CoV-2 virus infects host cells through ACE2 and TMPRSS2 receptors. Protein levels of ACE2 and TMPRSS2 have not been assessed in allergic airways. Method(s): We collected biopsies of endobronchial tissue from steroid-naive mild allergic asthmatics (AA n=23) and non-asthmatic controls (NA n=11), and inferior nasal turbinate tissue from AA with allergic rhinitis (AR n=8) and nonAA/AR controls (NR n=5). Tissue was immune-stained for SARS-CoV-2 receptor ACE2 and surface protein TMPRSS2. The number of immuno-positive cells in epithelium and laminae propria was expressed per mm2 of tissue. Result(s): The number of cells expressing ACE2 was higher in AA endobronchial tissue compared to NA control and AR nasal tissue. TMPRSS2 was higher in AR nasal tissue compared to NR control, and higher in control NA endobronchial tissue versus control NR nasal tissue. Co-expression of ACE2+TMPRSS2 was higher in AA endobronchial tissue versus NA control and trending higher in AR nasal tissue versus NR control (p=0.08). Conclusion(s): Overall, ACE2 is more highly expressed in endobronchial tissue versus nasal tissue, suggesting SARS-CoV-2 may more readily infect lower versus upper airways. It is unknown whether the higher expression of ACE2 and ACE2+TMPRSS2 observed in the airways of mild allergic asthmatic donors versus control donors translates to higher susceptibility to infection.
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Introduction Entry factors angiotensin converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) facilitate Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) entry into the host cells. Despite SARS-CoV-2s preference for respiratory system, extra-pulmonary organ involvement has been suggested. Recent studies report that SARS-CoV-2 leads to direct hepatic impairment in COVID-19 patients, necessitating further investigations about hepatic involvement. ACE2 and TMPRSS2 are expressed in primary human hepatocytes (PHH), suggesting a possible susceptibility to SARS-CoV-2. Despite this, data on infection and factors modulating functional regulation of SARS-CoV-2 infection in PHH are lacking. MicroRNAs (miRNAs) are approximately 22 nucleotide-long non-coding RNAs that have been shown to regulate various cellular processes including virus-host interactions. We aimed to study the susceptibility of PHH to SARS-CoV-2 and to evaluate the potential of miRNAs in modulating viral infection. Materials and methods We investigated the role of miRNAs to regulate SARS-CoV-2 infection in PHH in vitro. To strengthen our fndings, we analysed liver autopsies from COVID-19 patients. Results We demonstrate that PHH can be readily infected with SARS-CoV-2, resulting in robust replication and sustained host responses as indicated by the upregulation of several interferon-stimulated genes. In silico analyses unravelled miR-200c-3p, miR-429 and miR-141-3p as candidate miRNAs targeting ACE2 and, let-7c-5p targeting TMPRSS2. Expression of these miRNAs reduced SARS-CoV-2 infection in PHH. Furthermore, expression of several endogenous miRNAs was altered upon SARS-CoV-2 infection in PHH and human liver autopsies. Conclusion Our results show that PHH are susceptible towards SARS-CoV-2 and cellular miRNAs can diminish SARS-CoV-2 viral burden.
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The novel coronavirus severe acute respiratory syndrome Corona Virus-2 (SARS-CoV--2) has become a pandemic, as declared by WHO in March 2020 producing deleterious effects on patients worldwide. The angiotensin-converting enzyme-2 (ACE-2) has been recognized as the co-receptor for SARS-CoV-2 infections and may act as a therapeutic step in blocking the enzyme to re-duce SARS-CoV-2 expression and further cellular entry. Presently, the role of ACE-2 in coron-avirus disease 2019 (COVID-19) infection has been known and the experts have started working on the enzyme ACE-2 for the management and treatment of this pandemic disease. The binding of spike (S) protein of SARS-CoV-2 to these receptors is the most important step and plays a key role in viral replication, thus this enzyme is becoming the doorway for the entry and spread in the human body causing asymptomatic pneumonia and severe of which is leading to death. As no specific method to prevent and treat this disease is available, the use of ACE-2 as a targeting ligand with COVID-19 virus spike protein could be helpful in the proper management of SARS-CoV-2 pneu-monia.Copyright © 2021 Bentham Science Publishers.