Angiotensin-converting Enzyme 2 Protein Research Articles

A dual-target SPR screening system for simultaneous ligand discovery of SARS-CoV-2 spike protein and its receptor ACE2 from Chinese herbs

Traditional Chinese Medicine (TCM) is a supremely valuable resource for the development of drug discovery. Few methods are capable of hunting for potential molecule ligands from TCM towards more than one single protein target. In this study, a novel dual-target surface plasmon resonance (SPR) biosensor was developed to perform targeted compound screening of two key proteins involved in the cellular invasion process of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): the spike (S) protein receptor binding domain (RBD) and the angiotensin-converting enzyme 2 (ACE2). The screening and identification of active compounds from six Chinese herbs were conducted taking into consideration the multi-component and multi-target nature of Traditional Chinese Medicine (TCM). Puerarin from Radix Puerariae Lobatae was discovered to exhibit specific binding affinity to both S protein RBD and ACE2. The results highlight the efficiency of the dual-target SPR system in drug screening and provide a novel approach for exploring the targeted mechanisms of active components from Chinese herbs for disease treatment.

Utilizing noncatalytic ACE2 protein mutant as a competitive inhibitor to treat SARS-CoV-2 infection.

Angiotensin converting-enzyme 2 (ACE2) is an enzyme catalyzing the conversion of angiotensin 2 into angiotensin 1-7. ACE2 also serves as the receptor of several coronaviruses, including SARS-CoV-1 and SARS-CoV-2. Therefore, ACE2 could be utilized as a therapeutic target for treating these coronaviruses, ideally lacking enzymatic function. Based on structural analysis, specific mutations were introduced to generate mutants of ACE2 and ACE2-Fc (fusion protein of ACE2 and Fc region of IgG1). The enzyme activity, binding affinity, and neutralization abilities were measured. As predicted, five mutants (AMI081, AMI082, AMI083, AMI084, AMI090) have completely depleted ACE2 enzymatic activities. More importantly, enzyme-linked receptor-ligand assay (ELRLA) and surface plasmon resonance (SPR) results showed that 2 mutants (AMI082, AMI090) maintained binding activity to the viral spike proteins of SARS-CoV-1 and SARS-CoV-2. In An in vitro neutralization experiment using a pseudovirus, SARS-CoV-2 S1 spike protein-packed lentivirus particles, was also performed, showing that AMI082 and AMI090 significantly reduced GFP transgene expression. Further, in vitro virulent neutralization assays using SARS-CoV-2 (strain name: USA-WA1/2020) showed that AMI082 and AMI090 had remarkable inhibitory effects, indicated by comparable IC50 to wildtype ACE2 (5.33 µg/mL). In addition to the direct administration of mutant proteins, an alternative strategy for treating COVID-19 is through AAV delivery to achieve long-lasting effects. Therefore, AAV5 encoding AMI082 and AMI090 were packaged and transgene expression was assessed. In summary, these ACE2 mutants represent a novel approach to prevent or treat COVID-19 and other viruses with the same spike protein.

SARS-CoV-2 variant with the spike protein mutation F306L in the southern border provinces of Thailand

The southernmost part of Thailand is a unique and culturally diverse region that has been greatly affected by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) outbreak during the coronavirus disease-2019 pandemic. To gain insights into this situation, we analyzed 1942 whole-genome sequences of SARS-CoV-2 obtained from the five southernmost provinces of Thailand between April 2021 and March 2022, together with those publicly available in the Global Initiative on Sharing All Influenza Data database. Our analysis revealed evidence for transboundary transmissions of the virus in and out of the five southernmost provinces during the study period, from both domestic and international sources. The most prevalent viral variant in our sequence dataset was the Delta B.1.617.2.85 variant, also known as the Delta AY.85 variant, with many samples carrying a non-synonymous mutation F306L in their spike protein. Protein–protein docking and binding interface analyses suggested that the mutation may enhance the binding between the spike protein and host cell receptor protein angiotensin-converting enzyme 2, and we found that the mutation was significantly associated with an increased fatality rate. This mutation has also been observed in other SARS-CoV-2 variants, suggesting that it is of particular interest and should be monitored.

Endothelial factors and blood homocysteine level in adolescents with rheumatic diseases

It is known that the dysfunction of the endothelium has crucial role in many pathological conditions and underlines adverse cardiovascular events. The aim of our study was to determine biologically active substances in the blood that affect endothelial function and homocysteine level in adolescents with rheumatic diseases. Materials and methods. We examined 68 patients with rheumatic diseases, among them 25 patients with systemic lupus erythematosus (SLE) and 43 patients with juvenile idiopathic arthritis (JIA). Obtained results were compared with similar indicators of peers from the control group. All patients received basic therapy for 12 or more months at the time of examination. Biologically active substances (Homocysteine (Hcy), vascular endothelial growth factor (VEGF), high-sensitivity C-reactive protein (hs-CRP)) were studied by enzyme-linked immunosorbent assay, brain natriuretic peptide (NT-proBNP) by competitive immunoassay, and angiotensin-converting enzyme (ACE) by turbidimetric FAPGG kinetics method. Results. Patients with rheumatic diseases had a significantly higher level of BNP (p < 0.01). These changes were most significant in patients with SLE. The level of Hcy did not differ from the similar indicator of the control group, but in patients with SLE it was significantly higher (p < 0.01) than in patients with JIA. Conclusions. In patients with rheumatic diseases, biologically active substances level affecting the endothelium function depends on the disease. Biologically active substances affecting the function of the endothelium were within normal values. Thus, in children with SLE compared with JIA children, an increase in Hcy and NT-proBNP, and a decrease in ACE and hs-CRP protein were found. In children with JIA, normal levels of Hcy and ACE are accompanied by an increase in NT-proBNP and hs-CRP. In adolescents aged 10–18 years with SLE and JIA, multidirectional changes in biologically active substances and homocysteine, affecting the endothelial function of blood vessels were found.

Candesartan upregulates angiotensin-converting enzyme 2 in kidneys of male animals by decreased ubiquitination.

Candesartan is a common angiotensin-II receptor-1 blocker used for patients with cardiovascular and renal diseases. Angiotensin-converting enzyme 2 (ACE2) is a negative regulator of blood pressure (BP), and also a major receptor for coronaviruses. To determine whether and how candesartan upregulates ACE2, we examined BP and ACE2 in multi-organs from male and female C57BL/6J mice treated with candesartan (1 mg/kg, i.p.) for 7 days. Relative to the vehicle, candesartan lowered BP more in males than females; ACE2 protein abundances were increased in kidneys, not lungs, hearts, aorta, liver, spleen, brain, or serum, only from males. Ace2-mRNA was similar in kidneys. Candesartan also decreased BP in normal, hypertensive, and nephrotic male rats. The renal ACE2 was increased by the drug in normal and nephrotic male rats but not spontaneously hypertensive ones. In male mouse kidneys, ACE2 was distributed at sodium-hydrogen-exchanger-3 positive proximal-convoluted-tubules; ACE2-ubiquitination was decreased by candesartan, accompanied with increased ubiquitin-specific-protease-48 (USP48). In candesartan-treated mouse renal proximal-convoluted-tubule cells, ACE2 abundances and activities were increased while ACE2-ubiquitination and colocalization with lysosomal and proteosomal markers were decreased. The silence of USP48 by siRNA caused a reduction of ACE2 in the cells. Thus, the sex-differential ACE2 upregulation by candesartan in kidney from males may be due to the decreased ACE2-ubiquitination, associated with USP48, and consequent degradation in lysosomes and proteosomes. This is a novel mechanism and may shed light on candesartan-like-drug choice in men and women prone to coronavirus infections.

Piper sarmentosum Roxb. Inhibits Angiotensin-Converting Enzyme Activity in Phorbol 12-Myristate-13-Acetate-Induced Endothelial Cells.

Angiotensin-converting enzyme (ACE) plays a crucial role in the pathogenesis of hypertension. Piper sarmentosum Roxb., an herb known for its antihypertensive effect, lacks a comprehensive understanding of the mechanism underlying its antihypertensive action. This study aimed to elucidate the antihypertensive mechanism of aqueous extract of P. sarmentosum leaves (AEPS) via its modulation of the ACE pathway in phorbol 12-myristate-13-acetate (PMA)-induced human umbilical vein endothelial cells (HUVECs). HUVECs were divided into five groups: control, treatment with 200 µg/mL AEPS, induction 200 nM PMA, concomitant treatment with 200 nM PMA and 200 µg/mL AEPS, and treatment with 200 nM PMA and 0.06 μM captopril. Subsequently, ACE mRNA expression, protein level and activity, angiotensin II (Ang II) levels, and angiotensin II type 1 receptor (AT1R) and angiotensin II type 2 receptor (AT2R) mRNA expression in HUVECs were determined. AEPS successfully inhibited ACE mRNA expression, protein and activity, and angiotensin II levels in PMA-induced HUVECs. Additionally, AT1R expression was downregulated, whereas AT2R expression was upregulated. In conclusion, AEPS reduces the levels of ACE mRNA, protein and activity, Ang II, and AT1R expression in PMA-induced HUVECs. Thus, AEPS has the potential to be developed as an ACE inhibitor in the future.

Targeted Affinity Purification and Mechanism of Action of Angiotensin-Converting Enzyme (ACE) Inhibitory Peptides from Sea Cucumber Gonads.

Protein hydrolysates from sea cucumber (Apostichopus japonicus) gonads are rich in active materials with remarkable angiotensin-converting enzyme (ACE) inhibitory activity. Alcalase was used to hydrolyze sea cucumber gonads, and the hydrolysate was separated by the ultrafiltration membrane to produce a low-molecular-weight peptide component (less than 3 kDa) with good ACE inhibitory activity. The peptide component (less than 3 kDa) was isolated and purified using a combination method of ACE gel affinity chromatography and reverse high-performance liquid chromatography. The purified fractions were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the resulting products were filtered using structure-based virtual screening (SBVS) to obtain 20 peptides. Of those, three noncompetitive inhibitory peptides (DDQIHIF with an IC50 value of 333.5 μmol·L-1, HDWWKER with an IC50 value of 583.6 μmol·L-1, and THDWWKER with an IC50 value of 1291.8 μmol·L-1) were further investigated based on their favorable pharmacochemical properties and ACE inhibitory activity. Molecular docking studies indicated that the three peptides were entirely enclosed within the ACE protein cavity, improving the overall stability of the complex through interaction forces with the ACE active site. The total free binding energies (ΔGtotal) for DDQIHIF, HDWWKER, and THDWWKER were -21.9 Kcal·mol-1, -71.6 Kcal·mol-1, and -69.1 Kcal·mol-1, respectively. Furthermore, a short-term assay of antihypertensive activity in spontaneously hypertensive rats (SHRs) revealed that HDWWKER could significantly decrease the systolic blood pressure (SBP) of SHRs after intravenous administration. The results showed that based on the better antihypertensive activity of the peptide in SHRs, the feasibility of targeted affinity purification and computer-aided drug discovery (CADD) for the efficient screening and preparation of ACE inhibitory peptide was verified, which provided a new idea of modern drug development method for clinical use.

Quercetin inhibits SARS-CoV-2 infection and prevents syncytium formation by cells co-expressing the viral spike protein and human ACE2

BackgroundSeveral in silico studies have determined that quercetin, a plant flavonol, could bind with strong affinity and low free energy to SARS-CoV-2 proteins involved in viral entry and replication, suggesting it could block infection of human cells by the virus. In the present study, we examined the ex vivo ability of quercetin to inhibit of SARS-CoV-2 replication and explored the mechanisms of this inhibition.MethodsGreen monkey kidney Vero E6 cells and in human colon carcinoma Caco-2 cells were infected with SARS-CoV-2 and incubated in presence of quercetin; the amount of replicated viral RNA was measured in spent media by RT-qPCR. Since the formation of syncytia is a mechanism of SARS-CoV-2 propagation, a syncytialization model was set up using human embryonic kidney HEK293 co-expressing SARS-CoV-2 Spike (S) protein and human angiotensin converting enzyme 2 (ACE2), [HEK293(S + ACE2) cells], to assess the effect of quercetin on this cytopathic event by microscopic imaging and protein immunoblotting.ResultsQuercetin inhibited SARS-CoV-2 replication in Vero E6 cells and Caco-2 cells in a concentration-dependent manner with a half inhibitory concentration (IC50) of 166.6 and 145.2 µM, respectively. It also inhibited syncytialization of HEK293(S + ACE2) cells with an IC50 of 156.7 µM. Spike and ACE2 co-expression was associated with decreased expression, increased proteolytic processing of the S protein, and diminished production of the fusogenic S2’ fragment of S. Furin, a proposed protease for this processing, was inhibited by quercetin in vitro with an IC50 of 116 µM.ConclusionThese findings suggest that at low 3-digit micromolar concentrations of quercetin could impair SARS-CoV-2 infection of human cells partly by blocking the fusion process that promotes its propagation.

Soluble Angiotensin-Converting Enzyme 2 Protein Improves Survival and Lowers Viral Titers in Lethal Mouse Model of Severe Acute Respiratory Syndrome Coronavirus Type 2 Infection with the Delta Variant.

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) utilizes angiotensin-converting enzyme 2 (ACE2) as its main receptor for cell entry. We bioengineered a soluble ACE2 protein termed ACE2 618-DDC-ABD that has increased binding to SARS-CoV-2 and prolonged duration of action. Here, we investigated the protective effect of this protein when administered intranasally to k18-hACE2 mice infected with the aggressive SARS-CoV-2 Delta variant. k18-hACE2 mice were infected with the SARS-CoV-2 Delta variant by inoculation of a lethal dose (2 × 104 PFU). ACE2 618-DDC-ABD (10 mg/kg) or PBS was administered intranasally six hours prior and 24 and 48 h post-viral inoculation. All animals in the PBS control group succumbed to the disease on day seven post-infection (0% survival), whereas, in contrast, there was only one casualty in the group that received ACE2 618-DDC-ABD (90% survival). Mice in the ACE2 618-DDC-ABD group had minimal disease as assessed using a clinical score and stable weight, and both brain and lung viral titers were markedly reduced. These findings demonstrate the efficacy of a bioengineered soluble ACE2 decoy with an extended duration of action in protecting against the aggressive Delta SARS-CoV-2 variant. Together with previous work, these findings underline the universal protective potential against current and future emerging SARS-CoV-2 variants.

Binding affinity between coronavirus spike protein and human ACE2 receptor

Coronaviruses (CoVs) pose a major risk to global public health due to their ability to infect diverse animal species and potential for emergence in humans. The CoV spike protein mediates viral entry into the cell and plays a crucial role in determining the binding affinity to host cell receptors. With particular emphasis on α- and β-coronaviruses that infect humans and domestic animals, current research on CoV receptor use suggests that the exploitation of the angiotensin-converting enzyme 2 (ACE2) receptor poses a significant threat for viral emergence with pandemic potential. This review summarizes the approaches used to study binding interactions between CoV spike proteins and the human ACE2 (hACE2) receptor. Solid-phase enzyme immunoassays and cell binding assays allow qualitative assessment of binding but lack quantitative evaluation of affinity. Surface plasmon resonance, Bio-layer interferometry, and Microscale Thermophoresis on the other hand, provide accurate affinity measurement through equilibrium dissociation constants (KD). In silico modeling predicts affinity through binding structure modeling, protein-protein docking simulations, and binding energy calculations but reveals inconsistent results due to the lack of a standardized approach. Machine learning and deep learning models utilize simulated and experimental protein-protein interaction data to elucidate the critical residues associated with CoV binding affinity to hACE2. Further optimization and standardization of existing approaches for studying binding affinity could aid pandemic preparedness. Specifically, prioritizing surveillance of CoVs that can bind to human receptors stands to mitigate the risk of zoonotic spillover.

Hyperoxia-induced airflow restriction and Renin-Angiotensin System expression in a bronchopulmonary dysplasia mouse model.

Mechanisms underlying hyperoxia-induced airflow restriction in the pediatric lung disease Bronchopulmonary dysplasia (BPD) are unclear. We hypothesized a role for Renin-Angiotensin System (RAS) activity in BPD. RAS is comprised of a pro-developmental pathway consisting of angiotensin converting enzyme-2 (ACE2) and angiotensin II receptor type 2 (AT2), and a pro-fibrotic pathway mediated by angiotensin II receptor type 1 (AT1). We investigated associations between neonatal hyperoxia, airflow restriction, and RAS activity in a BPD mouse model. C57 mouse pups were randomized to normoxic (FiO2 = 0.21) or hyperoxic (FiO2 = 0.75) conditions for 15 days (P1-P15). At P15, P20, and P30, we measured airflow restriction using plethysmography and ACE2, AT1, and AT2 mRNA and protein expression via polymerase chain reaction and Western Blot. Hyperoxia increased airflow restriction P15 and P20, decreased ACE2 and AT2 mRNA, decreased AT2 protein, and increased AT1 protein expression. ACE2 mRNA and protein remained suppressed at P20. By P30, airflow restriction and RAS expression did not differ between groups. Hyperoxia caused high airflow restriction, increased pulmonary expression of the pro-fibrotic RAS pathway, and decreased expression of the pro-developmental in our BPD mouse model. These associated findings may point to a causal role for RAS in hyperoxia-induced airflow restriction.

The expression of renin-angiotensin system components in human carotid plaque

Background/Aim. The renin-angiotensin system (RAS) is linked to the development of atherosclerosis (As), including its initiation and progression. Besides the well-known angio-tensin-converting enzyme (ACE), two newer RAS family members are related to vascular remodeling - ACE2 as a homolog of ACE and collectrin [transmembrane protein 27 (TMEM27)] as a homolog of ACE2. Up to now, a limited number of studies have examined the expression of these RAS components in advanced carotid plaque (CP) tissue based on the sex of the patients and plaque phenotypes (PPs). There are two ultrasonographically defined PPs - the hypoechogenic plaque (HoP) and the hyperechogenic plaque (HerP) phenotype. The aim of the study was to investigate whether there was a correlation between the expression of RAS components in the CP and the sex and PPs of patients. Methods. We examined 74 patients with advanced CP who underwent carotid endarterectomy. The intraplaque expression of RAS components was determined with the real-time polymerase chain reaction, using the TaqMan? gene expression assays and Western blot. A two-way ANOVA followed by a post-hoc Tukey test was performed for the statistical analysis of results. Results. No interaction was recorded between the sex of the patients and PPs in influencing the relative expression of ACE and TMEM27 messenger RNA (mRNA) (p > 0.05). In 56.06% of plaque samples, no expression of ACE2 mRNA was detected. Among the plaques where ACE2 mRNA expression was detected, its expression level was higher in females with the HoP phenotype compared to females with the HerP phenotype (p < 0.001). In patients with the HoP phenotype, females had higher expression of ACE2 mRNA than males (p < 0.05). In the male study group, ACE protein levels were significantly lower in the HoP phenotype compared to the HerP phenotype (p < 0.001). Fe-males with the HoP phenotype had significantly higher ACE protein levels than males with the HoP phenotype (p < 0.0001). Conclusion. Our results revealed alterations in the expression levels of ACE and ACE2, at the mRNA and protein levels, in advanced carotid As. These alterations are impacted by sex and PP and may indicate a switch from the balanced RAS/ACE/ACE2 axis in the healthy blood vessel to the unbalanced axis in vascular remodeling due to As.

TurboID-mediated proximity labeling technologies to identify virus co-receptors.

Virus receptors determine the tissue tropism of viruses and have a certain relationship with the clinical outcomes caused by viral infection, which is of great importance for the identification of virus receptors to understand the infection mechanism of viruses and to develop entry inhibitor. Proximity labeling (PL) is a new technique for studying protein-protein interactions, but it has not yet been applied to the identification of virus receptors or co-receptors. Here, we attempt to identify co-receptor of SARS-CoV-2 by employing TurboID-catalyzed PL. The membrane protein angiotensin-converting enzyme 2 (ACE2) was employed as a bait and conjugated to TurboID, and a A549 cell line with stable expression of ACE2-TurboID was constructed. SARS-CoV-2 pseudovirus were incubated with ACE2-TurboID stably expressed cell lines in the presence of biotin and ATP, which could initiate the catalytic activity of TurboID and tag adjacent endogenous proteins with biotin. Subsequently, the biotinylated proteins were harvested and identified by mass spectrometry. We identified a membrane protein, AXL, that has been functionally shown to mediate SARS-CoV-2 entry into host cells. Our data suggest that PL could be used to identify co-receptors for virus entry.

Eye Washing Downregulated Angiotensin-Converting Enzyme 2 in Conjunctival Tissue Samples from Smokers.

This study aimed to (1) determine whether the expression of angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 is increased in tobacco smokers, which potentially increases their susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and (2) assess whether eye rinsing can reduce susceptibility. This prospective study included 20 eyes of 10 smokers and 18 eyes of nine healthy non-smokers (control) for reverse-transcription polymerase chain reaction. This study also included 28 eyes of 14 smokers and 16 eyes of eight healthy non-smokers (control) for enzyme-linked immunosorbent assay. Tear and impression cytology samples were collected from the right eye of each patient. The left eye was then rinsed for 30 s, and after 5 min, the tear and impression cytology samples were collected in the same manner. The expression of the ACE2 gene was significantly higher in the conjunctiva of smokers (n = 17; median 3.07 copies/ng of total RNA) than in those of non-smokers (n = 17; median 1.92 copies/ng of total RNA, p = 0.003). Further, mRNA expression and protein levels of ACE2 were weakly correlated in smokers (r = 0.49). ACE2 protein levels in Schirmer's strip samples were significantly reduced from 5051 to 3202 pg/mL after eye washing (n = 10; p = 0.001). Ocular surface cells are susceptible to SARS-CoV-2 infection. Smoking may be a risk factor for SARS-CoV-2 infection, and eye rinsing may reduce the risk of infection.

USP2 inhibition prevents infection with ACE2-dependent coronaviruses in vitro and is protective against SARS-CoV-2 in mice.

Targeting angiotensin-converting enzyme 2 (ACE2) represents a promising and effective approach to combat not only the COVID-19 pandemic but also potential future pandemics arising from coronaviruses that depend on ACE2 for infection. Here, we report ubiquitin specific peptidase 2 (USP2) as a host-directed antiviral target; we further describe the development of MS102, an orally available USP2 inhibitor with viable antiviral activity against ACE2-dependent coronaviruses. Mechanistically, USP2 serves as a physiological deubiquitinase of ACE2, and targeted inhibition with specific small-molecule inhibitor ML364 leads to a marked and reversible reduction in ACE2 protein abundance, thereby blocking various ACE2-dependent coronaviruses tested. Using human ACE2 transgenic mouse models, we further demonstrate that ML364 efficiently controls disease caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as evidenced by reduced viral loads and ameliorated lung inflammation. Furthermore, we improved the in vivo performance of ML364 in terms of both pharmacokinetics and antiviral activity. The resulting lead compound, MS102, holds promise as an oral therapeutic option for treating infections with coronaviruses that are reliant on ACE2.

Myocardial Angiotensin-Converting Enzyme 2 Protein Expression in Ischemic Heart Failure.

The angiotensin-converting enzyme 2 (ACE2)-angiotensin-(1-7)-Mas receptor axis plays a significant role in regulating myocardial remodeling and the development of heart failure (HF), with ACE2 being the primary focus. However, contemporary understanding of the membrane-bound form of the human ACE2 protein remains insufficient. The purpose of this study was to determine the expression of ACE2 protein in different cells of the left ventricular myocardium in non-diseased hearts and at various stages of ischemic HF. A total of 103 myocardial tissue samples from the left ventricle underwent quantitative and semi-quantitative immunohistochemical analysis. Upon assessing ACE2 immunostaining in all myocardial cells through unselective digital image analysis, there was no change in the stage A HF group. Nevertheless, the expression of ACE2 membrane protein in cardiomyocytes showed a tendency to increase, while non-cardiomyocyte ACE2 expression decreased significantly (p < 0.001). In the stage B HF group, the intensity of ACE2 immunostaining continued to increase with rising cardiomyocyte ACE2 expression (p < 0.001). Non-cardiomyocyte expression, in contrast, remained similar to that observed in the stage A HF group. In the stages C/D HF group, ACE2 expression reached its highest level in cardiomyocytes (p < 0.001), while ACE2 expression in non-cardiomyocytes was the lowest (p < 0.001). These changes in ACE2 protein levels are associated with left ventricular remodeling in ischemic HF.

In Silico Screening of Chrysin Derivatives as Drug Leads Against Covid-19

The current investigation was aimed at in silico studies of some selected chrysin derivatives to evaluate their activity in attenuation of COVID 19. In this study 50 chrysin derivatives were selected and Remedesivir was used as standard in assessing the anti-viral activity. To assess the ADMET potential of compounds, primarily drug-like properties and bioactivity scores were calculated. Using PATCHDOCK software, binding fitness scores for SARS COV2 protease and Angiotensin Converting Enzyme proteins were determined using molecular docking studies. According to results of in silico studies, derivatives of chrysin may offer promising leads for development of drugs with good antiviral properties against COVID 19.

Beluga whale and bottlenose dolphin ACE2 proteins allow cell entry mediated by spike protein from three variants of SARS-CoV-2.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viruses infect numerous non-human species. Spillover of SARS-CoV-2 into novel animal reservoirs may present a danger to host individuals of these species, particularly worrisome in populations already endangered or threatened by extinction. In addition, emergence in new reservoirs could pose spillback threats to humans, especially in the form of virus variants that further mutate when infecting other animal hosts. Previous work suggests beluga whales (Delphinapterus leucas) and bottlenose dolphins (Tursiops truncatus) may be at risk owing to their formation of social groups, contact with humans, exposure to contaminated wastewater, and structure of their angiotensin-converting enzyme 2 (ACE2) proteins, which SARS-CoV-2 uses as a cellular receptor. We examined marine-mammal susceptibility to virus infection by challenging 293T cells expressing beluga or dolphin ACE2 with pseudovirions bearing the SARS-CoV-2 spike protein. Beluga and dolphin ACE2 were sufficient to allow cell entry by an early pandemic isolate (Wuhan-Hu-1) and two evolved variants (Delta B.1.617.2 and Omicron BA.1 strains). We conclude that SARS-CoV-2 poses a potential threat to marine mammal reservoirs that should be considered in surveillance efforts.

Susceptibility of bovine to SARS-CoV-2 variants of concern: insights from ACE2, AXL, and NRP1 receptors

The possibilities of cross-species transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) between humans and important livestock species are not yet known. Herein, we used the structural and genetic alignment and surface potential analysis of the amino acid (aa) in angiotensin-converting enzyme 2 (ACE2), tyrosine kinase receptor UFO (AXL), and neuropilin 1 (NRP1) in different species with substantial public health importance. The residues interfacing with the N-terminal domain (NTD) or receptor-binding domain (RBD) of S were aligned to screen the critical aa sites that determined the susceptibility of the SARS-CoV-2 to the host. We found that AXL and NRP1 proteins might be used as the receptors of SARS-CoV-2 in bovines. However, ACE2 protein may not be considered to be involved in the cross-species transmission of SARS-CoV-2 VOCs in cattle because the key residues of the ACE2-S-binding interface were different from those in known susceptible species. This study indicated that emerging SARS-CoV-2 variants potentially expand species tropism to bovines through AXL and NRP1 proteins.

MOLECULAR DOCKING AND DYNAMIC SIMULATION-BASED SCREENING IDENTIFIES INHIBITORS OF TARGETED SARS-COV-2 3CLPRO AND HUMAN ACE2

Objective: Several genetic variations of Severe Acute Respiratory Syndrome coronavirus-2 (SARS-CoV-2) are continuously arising due to the uncontrolled dissemination of the virus during the pandemic. Omicron (B.1.1.529), the most prevalent variation of concern, has demonstrated extraordinary proliferation and pathogenicity and has emerged as the dominant variant as it has inflicted mass casualties worldwide. Methods: Impeding the expression of 3CLpro, a coronavirus protease that is essential for digesting the RNA polyproteins, and the human angiotensin-converting enzyme 2 (ACE2) that serves as a receptor for the viral protein is identified as a competent therapeutic target. In the current study, human ACE2 and the viral 3CLpro complex was the target for the designing of novel drugs against the lethal virus. The docked complex was validated by Procheck, and the covid ligand library was investigated for its pharmacological efficacy using admetSAR 2.0. The molecular docking study was performed with the screened compounds obtained from the PubChem database against the docked protein complex. Results: The ACE2 and 3CLpro proteins were docked together and the best docked complex was utilized for the analysis of the 1,87,419 compounds retreived from the PubChem COVID library, 18,642 compunds fulfilled the pharmacological screening and were appraised for docking with ACE2-3CLpro complex. The molecular docking results presented that the compounds 1-(4-fluorophenyl)-N'-(4-methylphenyl)propane-1,3-diamine (CID: 10038137) demonstrated significantly better binding (-18.7 kacl/mol) with favourable pharmacological properties and was therefore subjected to molecular dynamic simulations using Desmond Schrodinger 2019.2 GPU enabled package for 100 ns trajectory. The complex structure was observed to be stable after 15 ns and the average RMSD was observed to be ~0.65 nm. The complete binding energy of the complex with respect to MD simulation was-134.998+/-18.435 kj/mol which exposed that the inhibitor has a higher affinity towards the 3Clpro-ACE2 complex. Conclusion: Consequently, this compound can be used to develop anti-covid medications to combat complications associated with Omicron infection.