ACE2 Proteins Research Articles

The role of microRNAs in modulating SARS-CoV-2 infection in human cells: a systematic review.

MicroRNAs are gene expression regulators, associated with several human pathologies, including the ones caused by virus infections. Although their role in infection diseases is not completely known, they can exert double functions in the infected cell, by mediating the virus infection and/or regulating the immunity-related gene targets through complex networks of virus-host cell interactions. In this systematic review, the Pubmed, EMBASE, Scopus, Lilacs, Scielo, and EBSCO databases were searched for research articles published until October 22nd, 2020 that focused on describing the role, function, and/or association of miRNAs in SARS-CoV-2 human infection and COVID-19. Following the PRISMA 2009 protocol, 29 original research articles were selected. Most of the studies reported miRNA data based on the genome sequencing of SARS-CoV-2 isolates and computational prediction analysis. The latter predicted, by at least one independent study, 1266 host miRNAs to target the viral genome. Thirteen miRNAs were identified by four independent studies to target SARS-CoV-2 specific genes, suggested to act by interfering with their cleavage and/or translation process. The studies selected also reported on viral and host miRNAs that targeted host genes, on the expression levels of miRNAs in biological specimens of COVID-19 patients, and on the impact of viral genome mutations on miRNA function. Also, miRNAs that regulate the expression levels of the ACE2 and TMPRSS2 proteins, which are critical for the virus entrance in the host cells, were reported. In conclusion, despite the limited number of studies identified, based on the search terms and eligibility criteria applied, this systematic review provides evidence on the impact of miRNAs on SARS-CoV-2 infection and COVID-19. Although most of the reported viral/host miRNAs interactions were based on in silico prediction analysis, they demonstrate the relevance of the viral/host miRNA interaction for viral activity and host responses. In addition, the identified studies highlight the potential use of miRNAs as therapeutic targets against COVID-19, and other viral human diseases (This review was registered at the International Prospective Register of Systematic Reviews (PROSPERO) database (#CRD42020199290).

Chronic Intermittent Hypobaric Hypoxia Decreases High Blood Pressure by Stabilizing the Vascular Renin-Angiotensin System in Spontaneously Hypertensive Rats.

Background and AimsPrevious studies have demonstrated the anti-hypertensive effect of chronic intermittent hypobaric hypoxia (CIHH) in hypertensive rats. The present study investigated the anti-hypertensive effect of CIHH in spontaneously hypertensive rats (SHR) and the role of the renin-angiotensin system (RAS) in anti-hypertensive effect of CIHH.MethodsFifteen-week-old male SHR and WKY rats were divided into four groups: the SHR without CIHH treatment (SHR-CON), the SHR with CIHH treatment (SHR-CIHH), the WKY without CIHH treatment (WKY-CON), and the WKY with CIHH treatment (WKY-CIHH) groups. The SHR-CIHH and WKY-CIHH rats underwent 35-days of hypobaric hypoxia simulating an altitude of 4,000 m, 5 h per day. Arterial blood pressure and heart rate were recorded by biotelemetry, and angiotensin (Ang) II, Ang1–7, interleukin (IL)-6, tumor necrosis factor-alpha (TNF)-α, and IL-10 in serum and the mesenteric arteries were measured by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry, respectively. The microvessel tension recording technique was used to determine the contraction and relaxation of the mesenteric arteries. Hematoxylin and eosin and Masson’s staining were used to observe vascular morphology and fibrosis. Western blot was employed to detect the expression of the angiotensin-converting enzyme (ACE), ACE2, AT1, and Mas proteins in the mesenteric artery.ResultsThe biotelemetry result showed that CIHH decreased arterial blood pressure in SHR for 3–4 weeks (P < 0.01). The ELISA and immunohistochemistry results showed that CIHH decreased Ang II, but increased Ang1–7 in serum and the mesenteric arteries of SHR. In the CIHH-treated SHR, IL-6 and TNF-α decreased in serum and the mesenteric arteries, and IL-10 increased in serum (P < 0.05–0.01). The microvessel tension results revealed that CIHH inhibited vascular contraction with decreased Ang1–7 in the mesenteric arteries of SHR (P < 0.05–0.01). The staining results revealed that CIHH significantly improved vascular remodeling and fibrosis in SHR. The western blot results demonstrated that CIHH upregulated expression of the ACE2 and Mas proteins, and downregulated expression of the ACE and AT1 proteins (P < 0.05–0.01).ConclusionCIHH decreased high blood pressure in SHR, possibly by inhibiting RAS activity, downregulating the ACE-Ang II-AT1 axis and upregulating the ACE2-(Ang1-7)-Mas axis, which resulted in antagonized vascular remodeling and fibrosis, reduced inflammation, and enhanced vascular relaxation.

Evidence for CAT gene being functionally involved in the susceptibility of COVID-19.

Novel coronary pneumonia (COVID‐19) is a respiratory distress syndrome caused by a new type of coronavirus. Understanding the genetic basis of susceptibility and prognosis to COVID‐19 is of great significance to disease prevention, molecular typing, prognosis, and treatment. However, so far, there have been only two genome‐wide association studies (GWASs) on the susceptibility of COVID‐19. Starting with these reported DNA variants, we found the genes regulated by these variants through cis‐eQTL and cis‐meQTL acting. We further did a series of bioinformatics analysis on these potential risk genes. The analysis shows that the genetic variants on EHF regulate the expression of its neighbor CAT gene via cis‐eQTL. There was significant evidence that CAT and the SARS‐CoV‐2‐related S protein binding protein ACE2 interact with each other. Intracellular localization results showed that CAT and ACE2 proteins both exists in the cell membrane and extracellular area and their interaction could have an impact on the cell invasion ability of S protein. In addition, the expression of these three genes showed a significant positive correlation in the lungs. Based on these results, we propose that CAT plays a crucial intermediary role in binding effectiveness of ACE2, thereby affecting the susceptibility to COVID‐19.

Co-expression of the SARS-CoV-2 entry receptors ACE2 and TMPRSS2 in healthy human conjunctiva

The purpose of this study was to evaluate the expression of the SARS-CoV-2 receptors ACE2 and TMPRSS2 in an immortalized human conjunctival epithelial cell line and in healthy human conjunctiva excised during ocular surgery, using Western blot, confocal microscopy and immunohistochemistry. The Western blot showed that ACE2 and TMPRSS2 proteins were expressed in human immortalized conjunctival cells, and this was confirmed by confocal microscopy images, that demonstrated a marked cellular expression of the viral receptors and their co-localization on the cell membranes. Healthy conjunctival samples from 11 adult patients were excised during retinal detachment surgery. We found the expression of ACE2 and TMPRSS2 in all the conjunctival surgical specimens analyzed and their co-localization in the superficial conjunctival epithelium. The ACE2 Western blot levels and immunofluorescence staining for ACE2 were variable among specimens.These results suggest the susceptibility of the conjunctival epithelium to SARS-CoV-2 infection, even though with a possible interindividual variability.

Applications of Protein Secondary Structure Algorithms in SARS-CoV-2 Research.

Since the outset of COVID-19, the pandemic has prompted immediate global efforts to sequence SARS-CoV-2, and over 450 000 complete genomes have been publicly deposited over the course of 12 months. Despite this, comparative nucleotide and amino acid sequence analyses often fall short in answering key questions in vaccine design. For example, the binding affinity between different ACE2 receptors and SARS-COV-2 spike protein cannot be fully explained by amino acid similarity at ACE2 contact sites because protein structure similarities are not fully reflected by amino acid sequence similarities. To comprehensively compare protein homology, secondary structure (SS) analysis is required. While protein structure is slow and difficult to obtain, SS predictions can be made rapidly, and a well-predicted SS structure may serve as a viable proxy to gain biological insight. Here we review algorithms and information used in predicting protein SS to highlight its potential application in pandemics research. We also showed examples of how SS predictions can be used to compare ACE2 proteins and to evaluate the zoonotic origins of viruses. As computational tools are much faster than wet-lab experiments, these applications can be important for research especially in times when quickly obtained biological insights can help in speeding up response to pandemics.

Potential Natural Products Against Respiratory Viruses: A Perspective to Develop Anti-COVID-19 Medicines.

The emergence of viral pneumonia caused by a novel coronavirus (CoV), known as the 2019 novel coronavirus (2019-nCoV), resulted in a contagious acute respiratory infectious disease in December 2019 in Wuhan, Hubei Province, China. Its alarmingly quick transmission to many countries across the world and a considerable percentage of morbidity and mortality made the World Health Organization recognize it as a pandemic on March 11, 2020. The perceived risk of infection has led many research groups to study COVID-19 from different aspects. In this literature review, the phylogenetics and taxonomy of COVID-19 coronavirus, epidemiology, and respiratory viruses similar to COVID-19 and their mode of action are documented in an approach to understand the behavior of the current virus. Moreover, we suggest targeting the receptors of SARS-CoV and SARS-CoV-2 such as ACE2 and other proteins including 3CLpro and PLpro for improving antiviral activity and immune response against COVID-19 disease. Additionally, since phytochemicals play an essential role in complementary therapies for viral infections, we summarized different bioactive natural products against the mentioned respiratory viruses with a focus on influenza A, SARS-CoV, MERS, and COVID-19.Based on current literature, 130 compounds have antiviral potential, and of these, 94 metabolites demonstrated bioactivity against coronaviruses. Interestingly, these are classified in different groups of natural products, including alkaloids, flavonoids, terpenoids, and others. Most of these compounds comprise flavonoid skeletons. Based on our survey, xanthoangelol E (88), isolated from Angelica keiskei (Miq.) Koidz showed inhibitory activity against SARS-CoV PLpro with the best IC50 value of 1.2 μM. Additionally, hispidulin (3), quercetin (6), rutin (8), saikosaponin D (36), glycyrrhizin (47), and hesperetin (55) had remarkable antiviral potential against different viral infections. Among these compounds, quercetin (6) exhibited antiviral activities against influenza A, SARS-CoV, and COVID-19 and this seems to be a highly promising compound. In addition, our report discusses the obstacles and future perspectives to highlight the importance of developing screening programs to investigate potential natural medicines against COVID-19.

Shogaol, Bisdemethoxycurcumin, and Curcuminoid: Potential Zingiber Compounds Against COVID-19

Coronavirus disease (COVID-19) is a global pandemic in the world. Some treatments, including vaccines and potential drugs, are still developed. This study investigated the bioactive compounds of Zingiber officinale, Kaempferia rotunda, and Curcuma zedoaria as a potential inhibitor for ACE2 and RdRP proteins. Molecular docking was used for screening the bioactive compounds as ACE2 and RdRP inhibitors. Shogaol (CID 5281794), zingerone (CID 31211), chalcone (CID 637760), Ar-turmerone (CID 558221), bisdemothxycurcumin (CID 5315472), and curcuminoid (CID 101341353) interacted with angiotensin-converting enzyme receptor-2/ACE2 (PDB ID 2xd3) and RNA dependent RNA polymerase/RdRP (PDB ID 6xqb), then analyzed using Discovery studio v.19 program. Shogaol, zingerone, chalcone, ar-turmerone, bisdemethoxycurcumin, and curcuminoid bound to ACE2 and RdRP protein in some active sites. Zingerone, chalcone, and ar-turmerone are attached to the ACE-2 and then RdRP protein in similar active sites, suggesting those compounds stabilize the complex ACE-2 and RdRP protein. Shogaol interacted with the RdRP and ACE2 protein amino acid residues in the Shogaol-RdRP+ACE2 complex, indicating shogaol blocks the RdRP-ACE2 interaction. Then, bisdemethoxycurcumin and curcuminoid change the binding sites of ACE2 and RdRP protein when both compounds are bound to RdRP protein. This study suggested that shogaol, bisdemethoxycurcumin, and curcuminoid are potential drugs for COVID-19 prevention.

Flavonol morin targets host ACE2, IMP-α, PARP-1 and viral proteins of SARS-CoV-2, SARS-CoV and MERS-CoV critical for infection and survival: a computational analysis

A sudden outbreak of a novel coronavirus SARS-CoV-2 in 2019 has now emerged as a pandemic threatening to efface the existence of mankind. In absence of any valid and appropriate vaccines to combat this newly evolved agent, there is need of novel resource molecules for treatment and prophylaxis. To this effect, flavonol morin which is found in fruits, vegetables and various medicinal herbs has been evaluated for its antiviral potential in the present study. PASS analysis of morin versus reference antiviral drugs baricitinib, remdesivir and hydroxychloroquine revealed that morin displayed no violations of Lipinski’s rule of five and other druglikeness filters. Morin also displayed no tumorigenic, reproductive or irritant effects and exhibited good absorption and permeation through GI (clogP <5). In principal component analysis, morin appeared closest to baricitinib in 3D space. Morin displayed potent binding to spike glycoprotein, main protease 3CLPro and papain-like protease PLPro of SARS-CoV-2, SARS-CoV and MERS-CoV using molecular docking and significant binding to three viral-specific host proteins viz. human ACE2, importin-α and poly (ADP-ribose) polymerase (PARP)-1, further lending support to its antiviral efficacy. Additionally, morin displayed potent binding to pro-inflammatory cytokines IL-6, 8 and 10 also supporting its anti-inflammatory activity. MD simulation of morin with SARS-CoV-2 3CLPro and PLPro displayed strong stability at 300 K. Both complexes exhibited constant RMSDs of protein side chains and Cα atoms throughout the simulation run time. In conclusion, morin might hold considerable therapeutic potential for the treatment and management of not only COVID-19, but also SARS and MERS if studied further. Communicated by Ramaswamy H. Sarma

Human Oocytes Express Both ACE2 and BSG Genes and Corresponding Proteins: Is SARS-CoV-2 Infection Possible?

In addition to a number of scientific and medical questions about SARS-CoV-2 infection that still need to be answered, there is also the question of how this highly virulent virus and COVID-19 disease affect gametogenesis in humans. Even more important is the question of whether the virus can also enter and infect oocytes and possibly alter them in an unknown way, which could also affect the development and status of the human embryo. The answers to these questions are still poorly known, so we reviewed the human oocyte transcriptome and proteome obtained in our previous studies and found that human oocytes from the in vitro fertilization program expressed both the ACE2 and BSG genes and the corresponding ACE2 and BSG proteins. This means that human oocytes possess the molecular ‘machinery’ to facilitate SARS-CoV-2 entrance and infection. According to various studies, especially in animal models, different viruses can infect oocytes, so infection of the oocyte with SARS-Cov-2 cannot be completely ruled out. A hypothetical model of human oocyte infection with this virus has been proposed.Graphical

Analysis of Intermediate Hosts and Susceptible Animals of SARS-CoV-2 by Computational Methods

COVID-19, a disease caused by SARS-CoV-2 that produces major symptoms of pneumonia, has been a disaster worldwide. The traceability of SARS-CoV-2 and the discovery of susceptible animal species is crucial to halt viral transmission and explore the mechanism of cross-species transmission. We selected 82 representative ACE2 sequences from the 1000 sequences with the closest homology to the hACE2 protein. All selected ACE2 proteins were subjected to homology modeling. Potential natural and intermediate hosts, as well as animal species susceptible to SARS-CoV-2, were analyzed systematically by calculation of the binding free energy of ACE2 protein to the RBD of SARS-CoV-2. Primates, some wild Felidae, civets, goats, spotted hyenas and golden hamsters are susceptible to SARS-CoV-2 and may be potential intermediate hosts, whereas pangolins, birds and reptiles are unlikely to be intermediate hosts. Mice, rats and guinea pig are not susceptible to SARS-CoV-2. Given their possible susceptibility, non-human primates, goats and golden hamsters could potentially be used as experimental models to examine SARS-CoV-2 infection without transgenesis. Herein, possible candidates for the natural and intermediate hosts of SARS-CoV-2 are suggested, to provide guidance for subsequent studies.

Could Peganum harmala be effective in the treatment of COVID-19?

Predominant molecules in Peganum harmala leaves were detected using gas chromatography-mass spectrometry (GC-MS). Based on the results of this analysis, most alkaloids, flavonoids and triterpenoids in found P. harmala was compiled from the literature in order to develop and lead the production of effective inhibitor drugs for ACE2, main protease, and RNA dependent RNA polymerase (RdRp) proteins of SARS-CoV-2 virus, which is today's most contagious and deadly disease. By comparing FDA-approved drugs used in the treatment of COVID-19, we aimed to determine whether the molecules in P. harmala are effective against SARS CoV-2 in silico. P. harmala molecules were selected as drug candidates from the PubChem web tool. Afterwards, molecular docking calculations of these inhibitor molecules were made with Maestro Molecular modeling program by Schrödinger. The comparison of molecules with high inhibitory activities with FDA-approved drugs was made. With molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) calculations, docking calculations of molecules that have high inhibitory activity, were tried to be verified by calculations in the range of 0-100 nanoseconds (Tab. 4, Fig. 6, Ref. 53).

Microscopic interactions between ivermectin and key human and viral proteins involved in SARS-CoV-2 infection.

The identification of chemical compounds able to bind specific sites of the human/viral proteins involved in the SARS-CoV-2 infection cycle is a prerequisite to design effective antiviral drugs. Here we conduct a molecular dynamics study with the aim to assess the interactions of ivermectin, an antiparasitic drug with broad-spectrum antiviral activity, with the human Angiotensin-Converting Enzyme 2 (ACE2), the viral 3CLpro and PLpro proteases, and the viral SARS Unique Domain (SUD). The drug/target interactions have been characterized in silico by describing the nature of the non-covalent interactions found and by measuring the extent of their time duration along the MD simulation. Results reveal that the ACE2 protein and the ACE2/RBD aggregates form the most persistent interactions with ivermectin, while the binding with the remaining viral proteins is more limited and unspecific.

Impact of SARS-CoV-2 on female fertility and pregnancy

SARS-CoV-2 is a causative agent of an enormous pandemic, initiated from Wuhan, China in 2019 and then spread around the world. This virus infects not only the human respiratory tract but also other organs such as the heart, kidneys, testis, etc. by interacting with ACE2 and TMPRSS2 proteins. Until now, evidence of SARS-CoV-2 infectability in women’s reproductive tract, zygotes, embryos, and risk of vertical transmission is limited. Furthermore, some results from several studies are still incompatible. Cells of women’s reproductive system may have less susceptibility to SARS-CoV-2. However, human oocytes and embryos may be more vulnerable to SARS-CoV-2 because of the difference in co-expression of two transmembrane proteins - ACE2 and TMPRSS2, in those cells. SARS-CoV-2 increases the risk of negative impacts on different levels in different stages of pregnancy, as well as has a potential risk of vertical transmission. The recent evidence suggests that we need to pay more attention to taking care of SARS-CoV-2 infected pregnant women, especially in the first trimester of pregnancy.

Deciphering the potential anti-COVID-19 active ingredients in Andrographis paniculata (Burm. F.) Nees by combination of network pharmacology, molecular docking, and molecular dynamics.

Currently, coronavirus disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 has posed an enormous threat to public health worldwide. An andrographolide sulfonates preparation, named Xiyanping injection in Chinese, which was prepared from the aqueous extract of Andrographis paniculata (Burm. F.) Nees, showed favorable therapeutic effectiveness on COVID-19, suggesting A. paniculata could contain powerful therapeutic ingredients against COVID-19. In this study, to search for the potential drug candidates for COVID-19 in the herb, 68 potential target proteins and 24 active ingredients from A. paniculata were screened out using TCMSP, STP, Genecards and TTD databases firstly. A. paniculata-Compound-Target network constructed by cytoscape software showed that the protein targets PTGS2, EGFR, MAPK14, etc. had a high network relevance value. GO and KEGG enrichment analysis indicated that the 24 compounds in A. paniculata might exert their therapeutic effects by the biological processes, cellular response to biotic stimulus, response to lipopolysaccharide, response to molecule of bacterial origin, etc. And AGE-RAGE signaling pathway in diabetic complications (hsa04933), Kaposi sarcoma-associated herpesvirus infection (hsa05167), Human cytomegalovirus infection (hsa05163), etc. were predicted as the most significant effect pathways. Andrographidine C (MOL008223) and andrographolide (MOL008232) were found with strong binding affinity to the target active sites of the potential targets by molecular docking. Ultimately, the application of molecular dynamics simulations demonstrated that andrographidine C could bind well to the ACE2 and PIK3CG proteins. This research identified novel molecules against COVID-19 for developing natural medicines from A. paniculate and also provides a possible explanation for the molecular mechanisms of Xiyanping Injection against COVID-19.

Molecular insights into the binding variance of the SARS-CoV-2 spike with human, cat and dog ACE2 proteins.

SARS-CoV-2 has recently caused an epidemic in humans and poses a huge threat to global public health. As a primary receptor of SARS-CoV-2, angiotensin-converting enzyme 2 (ACE2) exists in different hosts that are in close contact with humans, especially cats and dogs. However, the underlying mechanism of how the spike receptor binding domain (RBD) of SARS-CoV-2 cooperates with human ACE2 (hACE2), cat ACE2 (cACE2) and dog ACE2 (dACE2) and the variation in binding remains largely unsolved. Therefore, we explored the binding behavior of the spike RBD with cACE2, dACE2 and hACE2 via all-atom molecular dynamics simulations. In accordance with the binding free energies and residue interactions, the spike RBD has respective binding specificities with cACE2, dACE2 and hACE2, and the binding affinities decrease in the order of hACE2, cACE2, dACE2, mainly due to changes in the amino acids Q24L, H34Y, and M82T in cACE2 or dACE2. Furthermore, alanine scanning analysis results validated some key residues of the spike RBD interact with ACE2 and provided clues to the variation of amino acid that could influence the transmissibility or immune responses of SARS-CoV-2. Decreasing dynamic correlations strengths of ACE2 with the RBD were found in all hACE2-RBD, cACE2-RBD and dACE2-RBD systems. The ACE2 protein shows variable motion modes across the zinc metallopeptidase domain, which induces different interactions between ACE2 and the RBD. Our studies reveal that the motion pattern of the zinc metallopeptidase domain is critical to the binding behavior of RBD with ACE2. These findings could aid our understanding of selective recognition involving various ACE2 with the SARS-CoV-2 spike and shed further light on the binding mechanisms.

Human eggs, zygotes, and embryos express the receptor angiotensin 1-converting enzyme 2 and transmembrane serine protease 2 protein necessary for severe acute respiratory syndrome coronavirus 2 infection

ObjectiveTo study messenger ribonucleic acid (mRNA) and protein expressions of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry receptors (angiotensin 1-converting enzyme 2 [ACE2] and CD147) and proteases (transmembrane serine protease 2 [TMPRSS2] and cathepsin L [CTSL]) in human oocytes, embryos, and cumulus (CCs) and granulosa cells (GCs).DesignResearch study.SettingClinical in vitro fertilization (IVF) treatment center.PatientsPatients undergoing IVF were treated at the Colorado Center for Reproductive Medicine.InterventionsOocytes (germinal vesicle and metaphase II [MII]) and embryos (1-cell [1C] and blastocyst [BL]) were donated for research at the disposition by the patients undergoing IVF. Follicular cells (CC and GC) were collected from women undergoing egg retrieval after ovarian stimulation without an ovulatory trigger for in vitro maturation/IVF treatment cycles.Main Outcome MeasuresPresence or absence of ACE2, CD147, TMPRSS2, and CTSL mRNAs detected using quantitative reverse transcription polymerase chain reaction and proteins detected using capillary Western blotting in human oocytes, embryos, and ovarian follicular cells.ResultsThe quantitative reverse transcription polymerase chain reaction analysis revealed high abundance of ACE2 gene transcripts in germinal vesicle and MII oocytes than in CC, GC, and BL. ACE2 protein was present only in the MII oocytes, and 1C and BL embryos, but other ACE2 protein variants were observed in all the samples. TMPRSS2 protein was present in all the samples, whereas mRNA was observed only in the BL stage. All the samples were positive for CD147 and CTSL mRNA expressions. However, CCs and GCs were the only samples that showed coexpression of both CD147 and CTSL proteins in low abundance.ConclusionsCCs and GCs are the least susceptible to SARS-CoV-2 infection because of lack of the required combination of receptors and proteases (ACE2/TMPRSS2 or CD147/CTSL) in high abundance. The coexpression of ACE2 and TMPRSS2 proteins in the MII oocytes, zygotes, and BLs demonstrated that these gametes and embryos have the cellular machinery required and, thus, are potentially susceptible to SARS-CoV-2 infection if exposed to the virus. However, we do not know whether the infection occurs in vivo or in vitro in an assisted reproductive technology setting yet.

Identifying the Zoonotic Origin of SARS-CoV-2 by Modeling the Binding Affinity between the Spike Receptor-Binding Domain and Host ACE2.

Despite considerable research progress on SARS-CoV-2, the direct zoonotic origin (intermediate host) of the virus remains ambiguous. The most definitive approach to identify the intermediate host would be the detection of SARS-CoV-2-like coronaviruses in wild animals. However, due to the high number of animal species, it is not feasible to screen all the species in the laboratory. Given that binding to ACE2 proteins is the first step for the coronaviruses to invade host cells, we propose a computational pipeline to identify potential intermediate hosts of SARS-CoV-2 by modeling the binding affinity between the Spike receptor-binding domain (RBD) and host ACE2. Using this pipeline, we systematically examined 285 ACE2 variants from mammals, birds, fish, reptiles, and amphibians, and found that the binding energies calculated for the modeled Spike-RBD/ACE2 complex structures correlated closely with the effectiveness of animal infection as determined by multiple experimental data sets. Built on the optimized binding affinity cutoff, we suggest a set of 96 mammals, including 48 experimentally investigated ones, which are permissive to SARS-CoV-2, with candidates from primates, rodents, and carnivores at the highest risk of infection. Overall, this work not only suggests a limited range of potential intermediate SARS-CoV-2 hosts for further experimental investigation, but also, more importantly, it proposes a new structure-based approach to general zoonotic origin and susceptibility analyses that are critical for human infectious disease control and wildlife protection.

Blocking of the High-Affinity Interaction-Synapse Between SARS-CoV-2 Spike and Human ACE2 Proteins Likely Requires Multiple High-Affinity Antibodies: An Immune Perspective.

The pandemic of Coronavirus Disease 2019 (COVID-19) caused by SARS-CoV-2 has induced global eagerness to develop vaccines and therapeutics for treating COVID-19, including neutralizing antibodies. To develop effective therapeutic antibodies against SARS-CoV-2, it is critical to understand the interaction between viral and host's proteins. The human ACE2 (hACE2) protein is the crucial target for the SARS-CoV's Spike protein that allows the virus to adhere to host epithelial cells. X-ray crystal structures and biophysical properties of protein-protein interactions reveal a large interaction surface with high binding-affinity between SARS-CoV-2 and hACE2 (18 interactions), at least 15-fold stronger than between SARS-CoV-1 and hACE2 (eight interactions). This suggests that antibodies against CoV-1 infection might not be very efficient against CoV-2. Furthermore, interspecies comparisons indicate that ACE2 proteins of man and cat are far closer than dog, ferret, mouse, and rat with significant differences in binding-affinity between Spike and ACE2 proteins. This strengthens the notion of productive SARS-CoV-2 transmission between felines and humans and that classical animal models are not optimally suited for evaluating therapeutic antibodies. The large interaction surface with strong affinity between SARS-CoV-2 and hACE2 (dG−12.4) poses a huge challenge to develop reliable antibody therapy that truly blocks SARS-CoV-2 adherence and infection. We gauge that single antibodies against single epitopes might not sufficiently interfere with the strong interaction-synapse between Spike and hACE2 proteins. Instead, appropriate combinations of high-affinity neutralizing antibodies against different epitopes might be needed, preferably of IgA-class for optimal and prolonged activity at epithelial layers of respiratory and intestine tracts.

COVID-2019 Locked down Impact on Dairy Industry in the World

Locked down is the rule and regulation which stop the movement of the people from one place to another while dairy industry is activities of agriculture which supply milk and different by products to world community. COVID-2019 is the virus which has killed so many people in the world. The world try how to control the problem of the COVID-2019, so each government of the world apply the locked down for the control of corona virus. Seeing to its importance the present study was arranged since June,2020 to analyze the COVID-2019 locked down impact on dairy industry in the world. Total 18 articles were downloaded from the net and wrote the result. The result indicates that locked down has decreased the demand of the dairy products in the world which have disturbed the socioeconomic condition of the dairy owner and weakened their economy. The COVID-2019 created the terror and fear in the world which have increased the locked down period in the world and create shortage in the fodder of the dairy animal while in some area considered animal to the carrier of the corona virus in the world. They told that corona has spread from the soup of bat while bat belong to mammalian family, So all world doctors claimed that animal also play great role in COVID-2019 as a carrier. Experiment in different world countries were launched and found that corona also affects different animal of the world. Among these animals, ferret, tiger, lion, cat, camel, civet are the animals which play great role in this virus spreading in the world. One recent experiment found that cells with ACE2 proteins from humans, horseshoe bats, civets, and pigs could be infected with the virus, while mice could not. Smith explained that these strains have narrow host ranges, and the chance that a human strain of coronavirus would come from a cow or calf is extremely low. The world scientists also thought how to control the situation for the future because some animal play great role as a reservoir as a host. The study further explains that the locked down has damaged the dairy industry of the world. Particularly Canada, USA, Russia, Iran, China have claimed that corona virus has mostly affected the workers of the meat and milk plants companies and because of this all industries of the dairy were closed which have directly affect the export of the dairy product in the world. Due to locked down the demand of the product decreased and the price level also declined of the dairy product in the world which have totally closed the production of the dairy products in the world market. It was also observed that Locked down rule regulation were not fully implemented because of this the swing of the corona in the world is still continued and from the beginning more people w infected and the number of affected reached to 64 laces while the death number was reached to 3 laces in the world. On the basis of problems the study recommends that to locked down should be continued and rule regulation should be fully applied in the world; Wash hand sanitizer should be applied on proper places of the body; Who goes against the rule should be punished; Army and honest personal should be deployed on duty; Rich people should be helped the poor community of the world; Credit and market facilities should be provided to dairy owner; Dairy owner should be exempted from the tax in the world; Training should be arranged for awareness of the community in the world; Locked down should be developed in the world; All animal Corona test should be processed in the world for future controlling; Dairy product should be tested for corona virus in the world; Mask should be wore everywhere in the world according to environment.

Anti-NA Antibodies May Protect ACE2 from COVID-19 by Binding Spike Protein

Spike Protein of COVID-19 enters cells via ACE2 receptor on the surface of the human cell membrane. Downregulation of ACE2 by the neuraminidase(NA) protein. ACE2 proteins maybe directly cleaved by NA and then degraded through the proteasome pathway. May indicate that S-Protein has a protein structure partially similar to NA. Anti-NA antibodies may be considered to confer protection ACE2 against COVID-19 by binding S-Protein. The presence of a certain number of anti-NA antibodies in children made to promote the prevention of infection and reduce the severe morbidity of COVID-19.