SARS-CoV Receptor Research Articles

Reducing transmission of SARS-CoV-2 with intranasal prophylaxis.

Reducing transmission of SARS-CoV-2 with intranasal prophylaxis.

Are losartan and imatinib effective against SARS-CoV2 pathogenesis? A pathophysiologic-based in silico study.

Proposing a theory about the pathophysiology of cytokine storm in COVID19, we were to find the potential drugs to treat this disease and to find any effect of these drugs on the virus infectivity through an in silico study. COVID-19-induced ARDS is linked to a cytokine storm phenomenon not explainable solely by the virus infectivity. Knowing that ACE2, the hydrolyzing enzyme of AngII and SARS-CoV2 receptor, downregulates when the virus enters the host cells, we hypothesize that hyperacute AngII upregulation is the eliciting factor of this ARDS. We were to validate this theory through reviewing previous studies to figure out the role of overzealous activation of AT1R in ARDS. According to this theory losartan may attenuate ARDS in this disease. Imatinib, has previously been elucidated to be promising in modulating lung inflammatory reactions and virus infectivity in SARS and MERS. We did an in silico study to uncover any probable other unconsidered inhibitory effects of losartan and imatinib against SARS-CoV2 pathogenesis. Reviewing the literature, we could find that over-activation of AT1R could explain precisely the mechanism of cytokine storm in COVID19. Our in silico study revealed that losartan and imatinib could probably: (1) decline SARS-CoV2 affinity to ACE2. (2) inhibit the main protease and furin, (3) disturb papain-like protease and p38MAPK functions. Our reviewing on renin-angiotensin system showed that overzealous activation of AT1R by hyper-acute excess of AngII due to acute downregulation of ACE2 by SARS-CoV2 explains precisely the mechanism of cytokine storm in COVID-19. Besides, based on our in silico study we concluded that losartan and imatinib are promising in COVID19.Electronic supplementary materialThe online version of this article (10.1007/s40203-020-00058-7) contains supplementary material, which is available to authorized users.

Single-Cell Sequencing of Glioblastoma Reveals Central Nervous System Susceptibility to SARS-CoV-2

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the recent global COVID-19 outbreak, which led to a public health emergency. Entry of SARS-CoV-2 into human cells is dependent on the SARS-CoV receptor, angiotensin converting enzyme 2 (ACE2) receptor, and cathepsin. Cathepsin degrades the spike protein (S protein), which results in the entry of viral nucleic acid into the human host cell.MethodsWe explored the susceptibility of the central nervous system (CNS) to SARS-CoV-2 infection using single-cell transcriptome analysis of glioblastoma.ResultsThe results showed that ACE2 expression is relatively high in endothelial cells (ECs), bone marrow mesenchymal stem cells (BMSCs), and neural precursor cells (NPCs). Cathepsin B (Cat B) and cathepsin (Cat L) were also strongly expressed in various cell clusters within the glioblastoma microenvironment. Immunofluorescence staining of glioma and normal brain tissue chips further confirmed that ACE2 expression co-localized with CD31, CD73, and nestin, which confirmed the susceptibility to SARS-CoV-2 of nervous system cells, including ECs, BMSCs, and NPCs, from clinical specimens.ConclusionsThese findings reveal the mechanism of SARS-CoV-2 neural invasion and suggest that special attention should be paid to SARS-CoV-2–infected patients with neural symptoms, especially those who suffered a glioma.

Molecular basis of pangolin ACE2 engaged by COVID-19 virus

<p indent="0mm">The virus caused coronavirus disease 2019 (COVID-19 virus), also called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is the seventh coronavirus that can infect humans, and belongs to the genus β-coronavirus in the family <italic>Coronaviridae</italic>. As of 5 November 2020, SARS-CoV-2 has caused &gt;47000000 confirmed cases and &gt;1200000 related deaths in 219 countries and regions, bringing great challenges to global public health. Currently, there is no approved therapeutics or vaccines for the treatment of this disease. Several studies suggested SARS-CoV-2 might have originated from bats based on phylogenetic analysis, but the intermediate host of the virus is still unknown. Besides humans, cats, dogs, tigers, lions, minks, and other species have been reported to be infected by SARS-CoV-2. Several studies have reported pangolins as the only other mammalian species carrying coronaviruses related to SARS-CoV-2 besides bats, and suggested pangolins might be the intermediate host of SARS-CoV-2. Previously, we and other groups identified the angiotensin converting enzyme 2 (ACE2), the receptor of SARS-CoV, also functions as the entry receptor of SARS-CoV-2 and is recognized by the receptor binding domain (RBD) of the spike protein (S). Then, we elucidated the interaction between SARS-CoV-2 RBD and human ACE2 (hACE2) or cat ACE2 (cACE2), and also found that SARS-CoV-2 had broad potential host range, including domestic animals, companion pets and wild animals. In this study, we investigated the binding features of SARS-CoV-2 and two pangolin coronaviruses (pangolin-CoVs, GX/P2V/2017 and GD/1/2019) that recognize the receptors of both pangolin ACE2 (pACE2) and hACE2 using surface plasmon resonance (SPR) and structural methods. We further determined the crystal structure of SARS-CoV-2 S (RBD) in complex with pACE2 at a 2.3 Å resolution, revealing the similarity in the binding mode between SARS-CoV-2 RBD to hACE2 and to cACE2. Interestingly, we found that the SARS-CoV-2 RBD-pACE2 complex is more similar to the SARS-CoV-2 RBD-hACE2 complex than to SARS-CoV-2 RBD-cACE2 complex. Furthermore, we modeled the interactions of GX/P2V/2017 RBD and GD/1/2019 RBD bound to pACE2 and hACE2, respectively, and found that both viruses adopted similar binding mode as SARS-CoV-2 RBD to pACE2 and hACE2. However, crystal structure and homology modeling implied that the interaction between the three RBDs and pACE2 were slightly weaker than their respective binding to hACE2, which was consistent with the receptor-RBD protein interaction measured by SPR. These results could facilitate better understanding of SARS-CoV-2 evolution, indicate the potential of pangolin-CoVs to enter human population that may lead to another outbreak, and highlight the importance of monitoring pangolin CoVs to prevent possible spillovers.

Pulmonary pathology of COVID-19

Currently, animal-to-human transmission of SARS-CoV-2 (COVID-19) has not yet been confirmed, whereas the main mode of transmission is human-to-human. Droplets are the main route of human-to-human transmission, whereas aerosols could be another route in addition to stool-based transmission. Currently, no evidence is available to indicate intrauterine vertical transmission of SARS-CoV-2 (COVID-19) in pregnant women. In the host, the life cycle of coronavirus consists of 5 steps: 1) attachment, 2) penetration, 3) biosynthesis, 4) maturation, and 5) release. Once viruses bind to host receptors (attachment), they enter host cells, particularly type II pneumocytes via endocytosis or membrane fusion (penetration). Once viral contents are released inside the host cells, viral RNA enters the host’s nucleus for replication and making viral proteins (biosynthesis). New viral particles are produced (maturation) and released. Spike protein of coronaviruses which determines the diversity of coronaviruses and host tropism is composed of a transmembrane trimetric glycoprotein protruding from the viral surface. Structural and functional studies demonstrated that the spike protein the of coronaviruses can bind to angiotensin converting enzyme 2 (ACE2), a functional receptor for SARS-CoV. ACE2 expression is high in lung (high expression on lung epithelial cells), heart, ileum, and kidney. The lungs of severe COVID-19 patients demonstrate infiltration of a large number of inflammatory cells. Due to high ACE2 expression on the apical side of lung epithelial cells in the alveolar space, SARS-CoV-2 (COVID-19) can enter and destroy lung epithelial cells. Significant ACE2 expression on innate lymphoid cells (ILC)2, ILC3, and endothelial cells is also demonstrated. Pulmonary endothelial cells represent one third of the lung cells. Endothelial function includes promotion of anti-aggregation, fibrinolysis, and vasodilatation. Due to a significant role playing in thrombotic regulation, hypercoagulable profiles that are demonstrated in severe COVID-19 patients likely suggest significant endothelial injury. Pulmonary thrombosis and embolism accompanying elevation of d-dimer and fibrinogen levels have been demonstrated in severe COVID-19. In conclusion, whether these histopathological lesions are direct consequences of sepsis, SARS-CoV-2 (C)OVID-19), and /or multiple organ failure is difficult to conclude. Further studies on understanding the roles of ILC1, ILC2, ILC3, including the difference in response to SARS-CoV-2 (COVID-19) infection between children and adults are urgently needed to develop efficient targeted therapies.

Impact of COSARS-Cov-2 on Cardio-Pulmonary-Immune Signatures: A Review of Recent Developments with a Look toward the Future

In December 2019, the first case of patient with severe acute respiratory syndrome (SARS) caused by the novel coronavirus, SARS-CoV-2, was reported in Wuhan, Hubei Province, Central China. SARS-CoV-2 causes CoronaVirus Disease-2019 (COVID-19 or nCoV-19) disease, which rapidly spread all over the world. In response to this serious situation, on 30 January 2020, the World Health Organization (WHO) declared a global public health emergency of international concern, putting all health organizations on high alert. In mid-March 2020, WHO declared nCoV-19 a pandemic. By the end of September 2020, there were ~33.67 million confirmed cases and ~10.08 lakh deaths worldwide and the trend rising on each passing day. SARS-CoV-2 mainly infects the pulmonary system, but cause damage to other organs such as heart, kidney and intestine. Understanding the cardio-pulmonary issues underpinning of nCOV-19 pathogenesis is key to managing outcomes and mortality. SARS-CoV-2 uses the SARS-CoV receptor ACE2 for entry and the serine protease inhibitor TMPRSS2 for S protein priming. Alveolar cells and cardiomyocytes express ACE2 and TMPRSS2. In this Review, we summarize the current understanding of nCOV-19 pandemic from basic mechanisms to clinical perspectives, focusing on the interaction between SARS-CoV-2 and the cardio-pulmonary-immune signatures. The study provides crucial insights into the first step of SARS-CoV-2 infection, and potential targets for antiviral intervention.

COVID-19 and Renal Diseases: An Update.

It becomes increasingly evident that the SARS-CoV-2 infection is not limited to the respiratory system. In addition to being a target of the virus, the kidney also seems to have a substantial influence on the outcomes of the disease. Data was obtained by a comprehensive and non-systematic search in the PubMed, Cochrane, Scopus and SciELO databases, using mainly the terms "SARS-CoV-2", "COVID-19", "chronic kidney disease", "renal transplantation", acute kidney injury" and "renal dysfunction" Discussion: The membrane-bound angiotensin-converting enzyme 2 is the receptor for SARS-CoV- -2, and this interaction may lead to an imbalance of the Renin-Angiotensin System (RAS), associated with worse clinical presentations of COVID-19, including acute pulmonary injury, hyperinflammatory state and hematological alterations. In the framework of renal diseases, the development of acute kidney injury is associated mostly with immune alterations and direct cytopathic lesions by the virus, leading to higher mortality. As for chronic kidney disease, the patients at a non-terminal stage have a worse prognosis, while the hemodialysis patients appear to have mild courses of COVID-19, probably due to lower chances of being affected by the cytokine storm. Furthermore, the current scenario is unfavorable to kidney donation and transplantation. The relationship between COVID-19 and immunosuppression in kidney transplantation recipients has been greatly discussed to determine whether it increases mortality and how it interacts with immunosuppressive medications. The kidney and the RAS exert fundamental roles in the SARS-CoV-2 infection, and more research is required to have a complete understanding of the repercussions caused by COVID-19 in renal diseases.

Use of Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers During the COVID-19 Pandemic: A Modeling Analysis.

Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARB) are frequently prescribed for a range of diseases including hypertension, proteinuric chronic kidney disease, and heart failure. There is evidence indicating that these drugs upregulate ACE2, a key component of the renin-angiotensin system (RAS) and is found on the cells of a number of tissues, including the epithelial cells in the lungs. While ACE2 has a beneficial role in many diseases such as hypertension, diabetes, and cardiovascular disease, it also serves as a receptor for both SARS-CoV and SARS-CoV-2 via binding with the spike protein of the virus, thereby allowing it entry into host cells. Thus, it has been suggested that these therapies can theoretically increase the risk of SARS- CoV-2 infection and cause more severe COVID-19. Given the success of ACEi and ARBs in cardiovascular diseases, we seek to gain insights into the implications of these medications in the pathogenesis of COVID-19. To that end, we have developed a mathematical model that represents the RAS, binding of ACE2 with SARS-CoV-2 and the subsequent cell entry, and the host's acute inflammatory response. The model can simulate different levels of SARS-CoV-2 exposure, and represent the effect of commonly prescribed anti-hypertensive medications, ACEi and ARB, and predict tissue damage. Model simulations indicate that whether the extent of tissue damage may be exacerbated by ACEi or ARB treatment depends on a number of factors, including the level of existing inflammation, dosage, and the effect of the drugs on ACE2 protein abundance. The findings of this study can serve as the first step in the development of appropriate and more comprehensive guidelines for the prescription of ACEi and ARB in the current and future coronavirus pandemics.

Predicting the response of the dental pulp to SARS-CoV2 infection: a transcriptome-wide effect cross-analysis.

Pulpitis, inflammation of the dental pulp, is a disease that often necessitates emergency dental care. While pulpitis is considered to be a microbial disease primarily caused by bacteria, viruses have also been implicated in its pathogenesis. Here, we determined the expression of the SARS-CoV2 receptor, angiotensin converting enzyme 2 (ACE2) and its associated cellular serine protease TPMRSS2 in the dental pulp under normal and inflamed conditions. Next, we explored the relationship between the SARS-CoV-2/human interactome and genes expressed in pulpitis. Using existing datasets we show that both ACE2 and TPMRSS2 are expressed in the dental pulp and, that their expression does not change under conditions of inflammation. Furthermore, Master Regulator Analysis of the SARS-CoV2/human interactome identified 75 relevant genes whose expression values are either up-regulated or down-regulated in both the human interactome and pulpitis. Our results suggest that the dental pulp is vulnerable to SARS-CoV2 infection and that SARS-CoV-2 infection of the dental pulp may contribute to worse outcomes of pulpitis.

Network pharmacology analysis of the therapeutic mechanisms of the traditional Chinese herbal formula Lian Hua Qing Wen in Corona virus disease 2019 (COVID-19), gives fundamental support to the clinical use of LHQW

BackgroundThe traditional Chinese Medicine (TCM) herbal formula Lian Hua Qing Wen (LHQW) improves the results of COVID-19 treatment. Three very recent studies analyzed with network pharmacology some working mechanisms of LHQW. However, we used more techniques and also included Angiotensin converting enzyme 2 (ACE2) (a SARS-CoV receptor, possibly the viral entry point in alveolar lung cells) and the immune system, as cytokine storm is essential in the late phase. PurposeExtensive detailed Network Pharmacology analysis of the LHQW- treatment mechanism in COVID-19. MethodsTCM-herb-meridian and protein interaction network (PIN) of LHQW, based on LHQW herbs meridian information and the protein-protein interaction (PPI) information of the LHQW-component targets. Hub and topological property analyses to obtain crucial targets and construct the crucial LHQW-PIN. Functional modules determination using MCODE, GO and KEGG pathway analysis of biological processes and pathway enrichment. Intersection calculations between the LHQW-proteins and ACE2 co-expression-proteins. ResultsLHQW herbs have relationships to Stomach-, Heart-, Liver- and Spleen-systems, but most (10 of the 13 herbs) to the Lung system, indicating specific effects in lung diseases. The crucial LHQW PIN has the scale-free property, contains 2,480 targets, 160,266 PPIs and thirty functional modules. Six modules are enriched in leukocyte-mediated immunity, the interferon-gamma-mediated signaling pathway, immune response regulating signaling pathway, interleukin 23 mediated signaling pathway and Fc gamma receptor-mediated phagocytosis (GO analysis). These 6 are also enriched in cancer, immune system-, and viral infection diseases (KEGG). LHQW shared 189 proteins with ACE2 co-expression proteins. ConclusionsDetailed network analysis shows, that LHQW herbal TCM treatment modulates the inflammatory process, exerts antiviral effects and repairs lung injury. Moreover, it also relieves the “cytokine storm” and improves ACE2-expression-disorder-caused symptoms. These innovative findings give a rational pharmacological basis and support for treating COVID-19 and possibly other diseases with LHQW.

Advances in research on ACE2 as a receptor for 2019-nCoV.

Currently, a novel coronavirus (SARS-CoV-2, also called 2019-nCoV) has triggered pandemic Coronavirus Disease 2019 (COVID-19), an acute infectious respiratory disease that first became epidemic in Wuhan (China) and is now spreading worldwide. Although 2019-nCoV and SARS-CoV are very similar viruses genomically and structurally, the huge number of severe cases and deaths now being caused by 2019-nCoV infections has understandably prompted intense research on the receptor used by it to enter human cells. Angiotensin converting enzyme 2 (ACE2), a functional receptor for SARS-CoV, now appears likely to mediate 2019-nCoV entry into human cells. In this review, we describe the roles performed by ACE2 as an enzymatic catalyst and as a receptor for this novel coronavirus. We also summarize the latest research pertaining to the changes noted in ACE2 expression after viral binding, and the relationships relating to virus transmission and population susceptibility to it. Lastly, we speculate on the pathogenesis of COVID-19 and provide a useful reference for drug development against this aggressive virus.

Elements of Prevention Against the Coronavirus and “Hypothesis of Iodine Dependent Immune Collapse in Coronavirus Micro Clots “Microvascular Covid-19 Lung Vessels Obstructive Thrombo Inflammatory Syndrome”

Prevention of Covid-19 leads us to analyze the metabolic pathways related to the virus to highlight the critical points and use simple and economic resources to fight it. The goal of Epigenetic Naturology is to provide the body with the elements it can use to defend itself. Oral cavity mucosa may be a potentially high-risk route of COVID-19 infection. ACE2 (angiotensin-converting enzyme II) receptor on the oral mucosa, which is also the receptor of SARS-CoV and HCoV-NL63, was observed to be highly expressed by the epithelial cells of the tongue [1-3], therefore oral cavity is a critical site for the study and prevention of COVID-19 infection. The iodine and/or hydrogen peroxide might be helpful in antiviral effect [3-5] in the context of COVID-19 pandemic [5,6].

The SARS-CoV2 - ACE2 link: a physiopathological analysis

The Covid-19 pandemic represents an unsolved problem which has caused numerous fatalities. At the present time, there is no vaccination available or curative therapy. However, recent reports suggest that SARS-CoV2 acts upon its functional receptor ACE2 inducing a variety of deleterious effects such as inflammation, endothelial dysfunction, microangiopathy, myocarditis, thrombosis and myocardial infarction. The details of the SARS-CoV2 -ACE2 interaction are poorly understood and most of the hypothesis related to this are based on the extrapolation of previous research focusing on ACE2 as a receptor for SARS-CoV. Considering the similarities between SARS-CoV2 and SARS-CoV we have conducted e physiopathological analysis focusing on the key pathogenic role of ACE2 as a functional receptor for SARS-CoV2. In this context, we have identified several potential therapeutic targets which should be further evaluated in patients with Covid-19. It is likely that an efficient therapy for Covid-19 will be revealed by research investigating the binding of viral spike S protein to ACE2, and the immunological response determined by SARS-CoV2-ACE2 interaction, including the anti-viral role of plasmacytoid dendritic cells and anti-inflammatory reprogramming of macrophages. &nbsp;

Characterization of changes in global gene expression in the hearts and kidneys of transgenic mice overexpressing human angiotensin-converting enzyme 2

Human angiotensin-converting enzyme 2 (hACE2) has recently received a great attention due to it play a critical role as SARS-CoV receptor in the infection of human body. However, no further analysis for gene regulation has been performed in target tissues of model mice during hACE2 overproduction. To characterize changes in global gene expression in the hearts and kidneys of rtTA/hACE2 double transgenic (dTg) mice in response to hACE2 overexpression, total RNA extracted from these tissues from dTg mice after doxycycline (Dox) treatment was hybridized to oligonucleotide microarrays. Briefly, dTg mice were generated by cross-mating pα-MHC/rtTA Tg mice with pTRE/hACE2 Tg mice. The expression level of hACE2 protein was determined to be high in hearts, kidneys, and brains of dTg mice, whereas lung, liver, and testis tissues expressed low levels. The level of hACE2 was significantly enhanced in hearts and kidneys of the Dox+dTg group compared to that in Vehicle+dTg mice although consistent levels of mouse ACE2 (mACE2) remained in the same tissues. Based on the microarray analysis of heart tissue, 385 genes were differentially expressed, including 168 upregulated and 217 downregulated, when comparing non-Tg and Vehicle+dTg mice, whereas 216 genes were differentially expressed, including 136 upregulated and 80 downregulated, between Vehicle+dTg and Dox+dTg mice. In the kidneys, 402 genes were differentially expressed, including 159 upregulated and 243 downregulated, between non-Tg and Vehicle+dTg mice. Dox-treated dTg mice exhibited the differential expression of 4735 genes including 1636 upregulated and 3109 downregulated. Taken together, these findings suggested that several functional groups and individual genes can be considered biomarkers that respond to hACE2 overexpression in dTg mice. Moreover, our results provided a lot of useful information to predict physiological responses when these dTg mice are applied as a susceptible model for novel coronavirus (SARS-CoV, COVID-19) in both vaccine and drug development.

The potential effects of DPP-4 inhibitors on cardiovascular system in COVID-19 patients.

With the outbreak of a new coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), the public healthcare systems are facing great challenges. Coronavirus disease 2019 (COVID‐19) could develop into severe pneumonia, acute respiratory distress syndrome and multi‐organ failure. Remarkably, in addition to the respiratory symptoms, some COVID‐19 patients also suffer from cardiovascular injuries. Dipeptidyl peptidase‐4 (DPP‐4) is a ubiquitous glycoprotein which could act both as a cell membrane‐bound protein and a soluble enzymatic protein after cleavage and release into the circulation. Despite angiotensin‐converting enzyme 2 (ACE2), the recently recognized receptor of SARS‐CoV and SARS‐CoV‐2, which facilitated their entries into the host, DPP‐4 has been identified as the receptor of middle east respiratory syndrome coronavirus (MERS‐CoV). In the current review, we discussed the potential roles of DPP‐4 in COVID‐19 and the possible effects of DPP‐4 inhibitors on cardiovascular system in patients with COVID‐19.

Destabilizing the structural integrity of COVID-19 by caulerpin and its derivatives along with some antiviral drugs: An in silico approaches for a combination therapy.

Presently, the SARS-CoV-2 (COVID-19) pandemic has been spreading throughout the world. Some drugs such as lopinavir, simeprevir, hydroxychloroquine, chloroquine, and amprenavir have been recommended for COVID-19 treatment by some researchers, but these drugs were not effective enough against this virus. This study based on in silico approaches was aimed to increase the anti-COVID-19 activities of these drugs by using caulerpin and its derivatives as an adjunct drug against SARS-CoV-2 receptor proteins: the SARS-CoV-2 main protease and the SARS-CoV-2 spike protein. Caulerpin exhibited antiviral activities against chikungunya virus and herpes simplex virus type 1. Caulerpin and some of its derivatives showed inhibitory activity against Alzheimer’s disease. The web server ANCHOR revealed higher protein stability for the two receptors with disordered score (< 0.6). Molecular docking analysis showed that the binding energies of most of the caulerpin derivatives were higher than all the suggested drugs for the two receptors. Also, we deduced that inserting NH2, halogen, and vinyl groups can increase the binding affinity of caulerpin toward 6VYB and 6LU7, while inserting an alkyl group decreases the binding affinity of caulerpin toward 6VYB and 6LU7. So, we can modify the inhibitory effect of caulerpin against 6VYB and 6LU7 by inserting NH2, halogen, and vinyl groups. Based on the protein disordered results, the SARS-CoV-2 main protease and SARS-CoV-2 spike protein domain are highly stable proteins, so it is quite difficult to unstabilize their integrity by using individual drugs. Also, molecular dynamics (MD) simulation indicates that binding of the combination therapy of simeprevir and the candidate studied compounds to the receptors was stable and had no major effect on the flexibility of the protein throughout the simulations and provided a suitable basis for our study. So, this study suggested that caulerpin and its derivatives could be used as a combination therapy along with lopinavir, simeprevir, hydroxychloroquine, chloroquine, and amprenavir for disrupting the stability of SARS-CoV2 receptor proteins to increase the antiviral activity of these drugs.

Lack of antibody-mediated cross-protection between SARS-CoV-2 and SARS-CoV infections.

BackgroundThe novel coronavirus (SARS-CoV-2) shares approximately 80% whole genome sequence identity and 66% spike (S) protein identity with that of SARS-CoV. The cross-neutralization between these viruses is currently not well-defined.MethodsHere, by using the live SARS-CoV-2 virus infection assay as well as HIV-1 based pseudotyped-virus carrying the spike (S) gene of the SARS-CoV-2 (ppSARS-2) and SARS-CoV (ppSARS), we examined whether infections with SARS-CoV and SARS-CoV-2 can induce cross-neutralizing antibodies.FindingsWe confirmed that SARS-CoV-2 infects cells via angiotensin converting enzyme 2 (ACE2), the functional receptor for SARS-CoV, and we also found that the recombinant receptor binding domain (RBD) of the S protein of SARS-CoV effectively inhibits ppSARS-2 entry in Huh7.5 cells. However, convalescent sera from SARS-CoV and SARS-CoV-2 patients showed high neutralizing activity only against the homologous virus, with no or limited cross-neutralization activity against the other pseudotyped virus. Similar results were also observed in vaccination studies in mice.InterpretationOur study demonstrates that although both SARS-CoV and SARS-CoV-2 use ACE2 as a cellular receptor, the neutralization epitopes are not shared by these two closely-related viruses, highlighting challenges towards developing a universal vaccine against SARS-CoV related viruses.FundingThis work was supported by the National Key Research and Development Program of China, the National Major Project for Control and Prevention of Infectious Disease in China, and the One Belt and One Road Major Project for infectious diseases.

Evaluation of COVID-19 based on ACE2 expression in normal and cancer patients.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is now a serious public health problem. Angiotensin-converting enzyme 2 (ACE2) recognized as the receptor of SARS-CoV is also necessary for SARS-CoV-2. However, the impact of ACE2 on SARS-CoV-2 susceptibility and the situation of malignant tumor patients in this outbreak are unclear. So, it is important to understand the expressions of ACE2 in different normal tissues and cancers. The results showed that the kidneys, duodenum, intestine, gallbladder and testis had the highest ACE2 expressions, followed by the colon, rectum and seminal vesicles. The lungs had a very low expression. ACE2 expressions were upregulated in renal cancer, gastrointestinal tumor and lung cancer. ACE2 expression levels may affect SARS-CoV-2 infection and severity. A total of 3,421 cases with COVID-19 have been collected. Among them, 43 cases (1.26%) had malignant tumor coexisting conditions. The rate of severe events for malignant tumor patients was 39.02% (16/41), while the rate of severe events for all patients was 10.79% (194/1,798). The clinical symptoms and signs were studied for the following three systems: respiratory (31–92%), digestive (10–13%) and urinary systems (3.38%). It seems that symptom severity is not related to protein expression levels. This might be the reason for SARS-CoV-2 showing higher regeneration index and susceptibility. More research is needed to explore the mechanisms and treatments.

Beyond Anti-viral Effects of Chloroquine/Hydroxychloroquine.

As the world is severely affected by COVID-19 pandemic, the use of chloroquine and hydroxychloroquine in prevention or for the treatment of patients is allowed in multiple countries but remained at the center of much controversy in recent days. This review describes the properties of chloroquine and hydroxychloroquine, and highlights not only their anti-viral effects but also their important immune-modulatory properties and their well-known use in autoimmune diseases, including systemic lupus and arthritis. Chloroquine appears to inhibit in vitro SARS virus' replication and to interfere with SARS-CoV2 receptor (ACE2). Chloroquine and hydroxychloroquine impede lysosomal activity and autophagy, leading to a decrease of antigen processing and presentation. They are also known to interfere with endosomal Toll-like receptors signaling and cytosolic sensors of nucleic acids, which result in a decreased cellular activation and thereby a lower type I interferons and inflammatory cytokine secretion. Given the antiviral and anti-inflammatory properties of chloroquine and hydroxychloroquine, there is a rational to use them against SARS-CoV2 infection. However, the anti-interferon properties of these molecules might be detrimental, and impaired host immune responses against the virus. This duality could explain the discrepancy with the recently published studies on CQ/HCQ treatment efficacy in COVID-19 patients. Moreover, although these treatments could be an interesting potential strategy to limit progression toward uncontrolled inflammation, they do not appear per se sufficiently potent to control the whole inflammatory process in COVID-19, and more targeted and/or potent therapies should be required at least in add-on.

Hypothesis Of Protective Effect Anti Covid – 19 Of Iodine And/Or Hydrogen Peroxide Garglings And Mouthwashes To Prevent Infections Through Oral Mucosa

Oral cavity mucosa may be a potentially high-risk route of COVID-19 infection. ACE2 (angiotensin-converting enzyme II) receptor on the oral mucosa, which is also the receptor of SARS-CoV and HCoV-NL63, was observed to be highly expressed by the epithelial cells of the tongue [1], therefore oral cavity is a critical site for the study and prevention of COVID-19 infection. The iodine and/or hydrogen peroxide might be helpful in antiviral effect [2] in the context of COVID-19 pandemic [3]. A single oral dose of 130 mg potassium iodide was shown to accumulate in upper airway secretions. Since the virus also affects the eye mucosa, which is also a gateway to Covid 19, the use of Iodine povidone at 0.5- 0.6%, may enhance innate antiviral defenses [4].