Vero E6 Research Articles

Losartan and enalapril maleate differently influence SARS-CoV-2-infected vero cells

Background: The COVID-19 pandemic has posed significant challenges to global healthcare systems, particularly impacting individuals with pre-existing conditions like hypertension. This study sought to assess the impact of the antihypertensive medications, losartan and enalapril maleate on SARS-CoV-2 infected cells. Vero E6 cells were infected and treated in vitro, evaluating cell viability via the MTT colorimetric assay. Additionally, the study measured relative levels of viral RNA and selected gene messenger RNAs using reverse transcriptase followed by quantitative real-time polymerase chain reaction. Results: The findings revealed that losartan substantially reduced nucleocapsid RNA levels of SARS-CoV-2 to nearly undetectable levels, while enalapril maleate did not demonstrate a significant effect. In response to viral infection, the expression of il-18, p53, p21, and p62 increased compared to uninfected-untreated cells. Notably, il-6 expression was upregulated by both infection and treatments. A comparison between infected cells treated with losartan or enalapril maleate highlighted the presence of distinct profiles in the expression of il-6, p53, p21, and p62. Conclusions: The data from our study suggest that these medications could interfere with certain effects triggered by SARS-CoV-2 infection in Vero E6 cells. However, their influence appears to vary both quantitatively and qualitatively in the modulation of metabolic and signal transduction pathways.

Antitumor effect of the Newcastle disease virus strain NDV/Altai/pigeon/777/2010 on a model of solid Lewis carcinoma

Aim. To evaluate the efficacy of intratumoral administrations of the Newcastle disease virus strain NDV/Altai/pigeon/777/2010, to compare progression of the tumor nodes after virotherapy and to analyse pathomorphological changes in the tumor tissue in vitro and in vivo. Single intratumoral injections of the mesogenic strain of Newcastle disease virus NDV/Altai/pigeon/777/2010, isolated from a rock dove in Siberia, were done into outbred mice of the C57Bl/6 line into solid nodes of Lewis lung carcinoma that were grafted subcutaneously. Then the dynamics of tumor growth and pathomorphological changes in the tumor tissue were assessed and analyzed.It was shown that single intratumoral injections into immunocompetent C57Bl/6 mice with the mesogenic strain of Newcastle disease virus NDV/Altai/pigeon/777/2010 led to an increase in peculiar pathomorphological changes in the tumor tissue of subcutaneously grafted Lewis lung carcinoma and to a decrease in tumor growth compared to the control group of mice in vivo. A direct cytotoxic effect of the NDV strain on the Vero E6 cell line in vitro was noted.The results of this study indicate that the NDV strain NDV/Altai/pigeon/777/2010 has antitumor properties. This may enable clinical trials to prove its effectiveness as an antitumor drug.

Functionalization of cellulose nanocrystals with a potent antimalarial compound: Synthesis, characterization, and biological studies

Cellulosic materials, such as cellulose nanocrystals (CNCs), are biocompatible, biodegradable and have unique and fascinating biomedical applications. Calxinin (CXN), a potent multistage antimalarial compound was functionalised with CNCs to improve biocompatibility and enhance the bioactivity of the resulting CNC-CXN nano-conjugate. Elemental analysis, powder X-ray, SEM, AFM, Infrared, and solid-state NMR spectroscopic techniques confirmed the composition of novel CNC-CXN nano-conjugate. Next, CNC-CXN nano-conjugate did not exhibit apparent cytotoxic effects on the sensitive Vero E6 cell line up to a concentration of 4.66 μg/μl. The CNC-CXN nano-conjugate was also evaluated for its preliminary efficacy on Plasmodium falciparum (3D7) malaria parasite and showed a 50 % inhibitory concentration value of 0.02 μg/μl. Overall, the selectivity index (SI) of the CNC-CXN nano-conjugate significantly improved to 233, indicating its suitability for further validation studies in animal models.

Assessment of genetic diversity, tissue tropism, and antigenic properties of Grimsö betacoronavirus in Swedish bank voles (Clethrionomys glareolus)

Zoonotic coronaviruses can transmit over species barriers and infect humans. To understand the zoonotic potential of a betacoronavirus, Grimsö virus (GRIV), we investigated the geographic distribution and tissue tropism of GRIV in Swedish bank voles (Clethrionomys glareolus), and the antigenicity of the nucleocapsid (N) protein. We screened the lung tissues from animals collected in the southern Sweden by RT-PCR with primers targeting the spike gene. Seven out of 74 animals were found to be positive. They are genetically close to GRIV from Grimsö, central Sweden. Positive rodents were studied for the tissue distribution of GRIV and GRIV RNA was mainly found in the respiratory tract. After three attempts of virus isolation were failed, we successfully established a Vero E6 cell line that stably expressed GRIV N protein, which has no cross-reactivity with patient serum containing antibodies against SARS-CoV-2, or with MERS-CoV. However, a low level of cross-reactivity to common cold coronaviruses was found, likely HCoV-OC43 or HCoV-HKU1, probably due to shared linear epitopes. With the high prevalence and the suggested respiratory transmission route, GRIV may have a high potential for spillover and cross-species transmission, and future serological screening of GRIV infections in domestic animals or humans will be needed.

Cell-based high-content approach for SARS-CoV-2 neutralization identifies unique monoclonal antibodies and PI3K pathway inhibitors.

The sudden rise of the SARS-CoV-2 virus and the delay in the development of effective therapeutics to mitigate it made evident a need for ways to screen for compounds that can block infection and prevent further pathogenesis and spread. Yet, identifying effective drugs efficacious against viral infection and replication with minimal toxicity for the patient can be difficult. Monoclonal antibodies were shown to be effective, yet as the SARS-CoV-2 mutated, these antibodies became ineffective. Small molecule antivirals were identified using pseudovirus constructs to recapitulate infection in non-human cells, such as Vero E6 cells. However, the impact was limited due to poor translation of these compounds in the clinical setting. This is partly due to the lack of similarity of screening platforms to the in vivo physiology of the patient and partly because drugs effective in vitro showed dose-limiting toxicities. In this study, we performed two high-throughput screens in human lung adenocarcinoma cells with authentic SARS-CoV-2 virus to identify both monoclonal antibodies that neutralize the virus and clinically useful kinase inhibitors to block the virus and prioritize minimal host toxicity. Using high-content imaging combined with single-cell and multidimensional analysis, we identified antibodies and kinase inhibitors that reduce virus infection without affecting the host. Our screening technique uncovered novel antibodies and overlooked kinase inhibitors (i.e. PIK3i, mTORi, multiple RTKi) that could be effective against SARS-CoV-2 virus. Further characterization of these molecules will streamline the repurposing of compounds for the treatment of future pandemics and uncover novel mechanisms viruses use to hijack and infect host cells.

RpIFN-λ1 alleviates the clinical symptoms of porcine epidemic diarrhea

Porcine epidemic diarrhea (PED), caused by the porcine epidemic diarrhea virus (PEDV), primarily affects the jejunum and ileum of pigs. Interferons, glycoproteins with high species specificity and potent antiviral activity, are crucial in defending against viral infections. Unlike other interferons, interferon-lambda (IFN-λ) mainly acts on mucosal epithelial cells and exhibits robust antiviral activity at mucosal surfaces. However, the high cost limits the use of naturally extracted interferons in farming. In this study, we expressed recombinant porcine interferon-lambda 1 (rpIFN-λ1) in eukaryotic cells, demonstrating effective antiviral activity against PEDV in Vero E6 and IPI-FX cells. In vivo, rpIFN-λ1 alleviated clinical symptoms and intestinal damage, enhanced antioxidant capacity, reduced inflammation, and significantly improved the survival rate of piglets following PEDV infection. Both in vitro and in vivo studies confirmed that rpIFN-λ1 upregulated interferon-stimulated genes (ISGs) via the JAK-STAT pathway, thereby exerting antiviral effects. In conclusion, rpIFN-λ1 significantly inhibited PEDV replication and alleviated clinical symptoms. The selectivity of rpIFN-λ1 for intestinal cells and its ability to reduce viral shedding suggest that this agent is a promising antiviral for enteric viruses such as PEDV. Our findings highlight rpIFN-λ1 as a cost-effective, efficient, and novel strategy for antiviral treatment of PEDV.

Identification of nitrile-containing isoquinoline-related natural product derivatives as coronavirus entry inhibitors in silico and in vitro

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of infections and deaths worldwide since its emergence in Wuhan, China, in late 2019. Natural product inhibitors targeting the interaction between the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein and human angiotensin-converting enzyme 2 (ACE2), crucial for viral attachment and cellular entry, are of significant interest as potential antiviral agents. In this study a library of nitrile- and sulfur-containing natural product derived compounds were used for virtual drug screening against the RBD of the SARS-CoV-2 spike protein. The top 18 compounds from docking were tested for their efficacy to inhibit virus entry. In vitro experiments revealed that compounds 9, 14, and 15 inhibited SARS-CoV-2 pseudovirus and live virus entry in HEK-ACE2 and Vero E6 host cells at low micromolar IC50 values. Cell viability assays showed these compounds exerted low cytotoxicity towards MRC5, Vero E6, and HEK-ACE2 cell lines. Microscale thermophoresis revealed all three compounds strongly bound to the RBDs of SARS-CoV-2, SARS-CoV-2 XBB, SARS-CoV-1, MERS-CoV, and HCoV-HKU1, with their Kd values increasing as RBD sequence similarity decreased. Molecular docking studies indicated compounds 9, 14, and 15 bound to the SARS-CoV-2 spike protein RBD and interacted with hotspot amino acid residues required for the RBD-ACE2 interaction and cellular infection. These three nitrile-containing candidates, particularly compound 15, should be considered for further development as potential pan-coronavirus entry inhibitors.

The epidemiology and phylogenetic trends of Omicron subvariants from BA.5 to XBB.1 in Taiwan

BackgroundOmicron, a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, entered Taiwan at the end of 2021. The Taiwanese government ended its "zero-COVID" policy in March 2022. Multiple coronavirus disease 2019 (COVID-19) outbreaks began in April 2022. We monitored the replacement of Omicron subvariants after BA.1/BA.2 and analyzed their correlation with COVID-19 outbreaks. MethodsWe collected SARS-CoV-2 real-time qRTPCR-positive nasopharyngeal swabs from Kaohsiung Medical University Hospital (KMUH), Kaohsiung City, Taiwan, and performed sequencing for specimens exhibiting a cytopathic effect in Vero E6 cells to determine their clades and lineages. We analyzed the medical records of COVID-19 patients and identified hospitalization risk factor(s). We retrieved SARS-CoV-2 sequences identified in Taiwan from GISAID and analyzed their correlation with COVID-19 data from the Taiwan Centers for Disease Control. ResultsWe analyzed the phylogenesis of KMUH-47 to KMUH-104 (SARS-CoV-2 isolates identified herein) and all of the Omicron subvariants from BA.5 to XBB.1 (n = 1930). Age and comorbidities were hospitalization risk factors. Men generally exhibited a greater fatality rate than women. COVID-19-related deaths predominantly occurred in individuals over 70 years old. The COVID-19-related case fatality rate increased as nucleotide (NT) and amino acid (AA) substitutions increased. The number of COVID-19-related cases and deaths progressively decreased with each outbreak between August 2022 and October 2023. ConclusionHospitalization was associated with age and the presence of comorbidities. COVID-19-related fatality was linked to sex, age, and the accumulation of NT and AA substitutions in emerging Omicron subvariants.

Network pharmacology, molecular docking, and in vitro study on Aspilia pluriseta against prostate cancer

BackgroundCurrent prostate cancer treatments are associated with life-threatening side effects, prompting the search for effective and safer alternatives. Aspilia pluriseta Schweinf. ex Engl. has previously shown anticancer activity in lung and liver cancer cell lines. This study investigated its potential for prostate cancer.MethodsA crude extract of A. pluriseta root was prepared using dichloromethane/methanol (1:1 v/v) and partitioned into hexane, ethyl acetate, and water fractions. The MTT assay was used to assess the antiproliferative activity of the fractions. The active fractions were tested at 6.25–200 µg/ml on human prostate cancer DU-145 cells and non-cancerous Vero E6 cells. Qualitative phytochemical and gas chromatography-mass spectrometry (GC-MS) analyses were conducted to identify chemical compounds. Network pharmacology was employed to predict molecular targets and modes of action of the identified chemical compounds, with subsequent validation through molecular docking and real-time PCR.ResultsActive extracts included crude dichloromethane/methanol, hexane, and ethyl acetate fractions, inhibiting DU-145 cell proliferation with IC50 values of 16.94, 20.06, and 24.14 µg/ml, respectively. Selectivity indices were determined to be 6.04 (crude), 3.62 (hexane), and 6.68 (ethyl acetate). Identified phytochemicals comprised phenols, terpenoids, flavonoids, tannins, sterols, and saponins. GC-MS analysis revealed seventy-nine (79) compounds, with seven (7) meeting ideal drug candidate parameters; their hub gene targets included MAPK3, MAPK1, IL6, TP53, ESR1, PTGS2, MMP9, MDM2, AR, and MAP2K1, implicating regulation of PI3K/Akt, MAPK, and p53 signaling pathways as potential modes of action. Core compounds such as 1-heneicosanol, lanosterol, andrographolide, and retinoic acid exhibited strong binding activities, particularly lanosterol with MAPK21 (-9.7 kcal/mol), ESR1 (-8.9 kcal/mol), and MAPK3 (-8.8 kcal/mol). Treatment with A. pluriseta downregulated AR expression and upregulated p53, while also downregulating CDK1 and BCL-2 and upregulating caspase-3.ConclusionsA. pluriseta extracts inhibited DU-145 cell growth without causing cellular toxicity, suggesting great potential for development as an anti-prostate cancer agent. However, further in vitro and in vivo experiments are recommended.

Peptidomimetic Analogues Act as Effective Inhibitors against SARS-CoV-2 by Blocking the Function of Cathepsin L.

Cathepsin L (CatL) is a promising antiviral drug target of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as an important protease for cleaving the SARS-CoV-2 spike protein and enhancing viral entry to cells. We identified a tripeptide aldehyde candidate, D1-1, which exhibited inhibitory effects against SARS-CoV-2 in Vero E6 cells. The protease screening analysis and protein pull-down assays demonstrated the direct binding of D1-1 to CatL. Guided by molecular docking, we synthesized 72 analogues. Upon analyzing the structure-activity relationships of these inhibitors, the D6 series was developed. Among them, D6-3 functioned as the most potent CatL inhibitor (IC50 = 0.27 nM, EC50 = 0.26 μM). D6-3 effectively blocked the CatL function and substantially hindered the entry of the SARS-CoV-2 pseudovirus to cells. Our work presented novel compounds for targeting and inhibiting CatL, offering valuable insights into the development of SARS-CoV-2 antivirals.

4-(3-Phenylsulfonylindol-2-yl)-1-(pyridin-2-yl)piperazinyl-methanones as Potent Inhibitors of both SARS-CoV-2 and HCoV-OC43 Viruses.

SARS-CoV-2 and HCoV-OC43 belong to the same β genus of the Coronaviridae family. SARS-CoV-2 was responsible for the recent COVID-19 pandemic, and HCoV-OC43 is the etiological agent of mild upper respiratory tract infections. SARS-COV-2 and HCoV-OC43 co-infections were found in children with respiratory symptoms during the COVID-19 pandemic. The two β-coronaviruses share a high degree of homology between the 3CLpro active sites, so much so that the safer HCoV-OC43 has been suggested as a tool for the identification of new anti-SARS-COV-2 agents. Compounds 5 and 24 inhibited effectively both Wuhan and British SARS-CoV-2 patient isolates in Vero E6 cells and the HCoV-OC43 in MRC-5 cells at low micromolar concentrations. The inhibition was apparently exerted via targeting the 3CLpro active sites of both viruses. Compounds 5 and 24 at 100 μM inhibited the SARS-CoV-2 3CLpro activity of 61.78 and 67.30%, respectively. These findings highlight 5 and 24 as lead compounds of a novel class of antiviral agents with the potential to treat SARS-COV-2 and HCoV-OC43 infections.

In vitro study on efficacy of SKF7®, a Malaysian medicinal plant product against SARS-CoV-2

BackgroundIn early 2020, COVID-19 pandemic has mobilized researchers in finding new remedies including repurposing of medicinal plant products focusing on direct-acting antiviral and host-directed therapies. In this study, we performed an in vitro investigation on the standardized Marantodes pumilum extract (SKF7®) focusing on anti-SARS-CoV-2 and anti-inflammatory activities.MethodsAnti-SARS-CoV-2 potential of the SKF7® was evaluated in SARS-CoV-2-infected Vero E6 cells and SARS-CoV-2-infected A549 cells by cytopathic effect-based assay and RT-qPCR, respectively. Target based assays were performed on the SKF7® against the S1-ACE2 interaction and 3CL protease activities. Anti-inflammatory activity of the SKF7® was evaluated by nitric oxide inhibitory and TLR2/TLR4 receptor blocker assays.ResultsThe SKF7® inhibited wild-type Wuhan (EC50 of 21.99 µg/mL) and omicron (EC50 of 16.29 µg/mL) SARS-CoV-2 infections in Vero-E6 cells. The SKF7® also inhibited the wild-type SARS-CoV-2 infection in A549 cells (EC50 value of 6.31 µg/mL). The SKF7® prominently inhibited 3CL protease activity. The SKF7® inhibited the LPS induced-TLR4 response with the EC50 of 16.19 µg/mL.ConclusionsIn conclusion, our in vitro study highlighted anti-SARS-CoV-2 and anti-inflammatory potentials of the SKF7®. Future pre-clinical in vivo studies focusing on antiviral and immunomodulatory potentials of the SKF7® in affecting the COVID-19 pathogenesis are warranted.

Design, synthesis, and evaluation of novel oxyacanthine derivatives for anti-SARS-CoV-2 activity

Here, we report the synthesis of a series of oxyacanthine derivatives and evaluation for their anti-SARS-CoV-2 activity in Vero E6 cells. In order to eliminate the potential metabolic activation caused by para-methylene phenol moiety in oxyacanthine, totally 29 derivatives were designed and synthesized, resulting in 23 compounds with antivirus IC50 below 5.00 μM and 9 compounds with antivirus IC50 below 1.00 μM. Among them, amides compound 4a and 4d exhibited potent anti-SARS-CoV-2 activity and the most favorable selectivity index (SI) in vitro with the SI values of 115 and 70, respectively. The pharmacokinetic properties of 4a and 4d were also assessed. Much more improved exposure in mice, longer half-life (T1/2), and increased oral bioavailability were observed for both compounds 4a and 4d compared with oxyacanthine.

Therapeutic potential of mesenchymal stem cell-derived extracellular vesicles in SARS-CoV-2 and H1N1 influenza-induced acute lung injury.

Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) have shown anti-inflammatory potential in multiple inflammatory diseases. In the March 2022 issue of the Journal of Extracellular Vesicles, it was shown that EVs from human MSCs can suppress severe acute respiratory distress syndrome, coronavirus 2 (SARS-CoV-2) replication and can mitigate the production and release of infectious virions. We therefore hypothesized that MSC-EVs have an anti-viral effect in SARS-CoV-2 infection in vivo. We extended this question to ask whether also other respiratory viral infections could be treated by MSC-EVs. Adipose stem cell-derived EVs (ASC-EVs) were isolated using tangential flow filtration from conditioned media obtained from a multi-flask cell culture system. The effects of the ASC-EVs were tested in Vero E6 cells in vitro. ASC-EVs were also given i.v. to SARS-CoV-2 infected Syrian Hamsters, and H1N1 influenza virus infected mice. The ASC-EVs attenuated SARS-CoV-2 virus replication in Vero E6 cells and reduced body weight and signs of lung injury in infected Syrian hamsters. Furthermore, ASC-EVs increased the survival rate of influenza A-infected mice and attenuated signs of lung injury. In summary, this study suggests that ASC-EVs can have beneficial therapeutic effects in models of virus-infection-associated acute lung injury and may potentially be developed to treat lung injury in humans.

Targeting host inducible-heat shock protein 70 with PES-Cl is a promising antiviral strategy against SARS-CoV-2 infection and pathogenesis

One of the fundamental mechanisms developed by the host to contain the highly infectious and rapidly proliferating SARS-coronavirus is elevation of body temperature, a natural fallout of which is heat shock proteins over-expression. Here, for the first time, we demonstrate that the SARS-CoV-2 exploits the host Heat shock protein 70 (Hsp70) chaperone for its entry and propagation, and blocking it can combat the infection. SARS-CoV-2 infection as well as febrile temperature enhanced Hsp70 expression in host Vero E6 cells. Furthermore, heat shock or viral infection elevated the host cell autophagic response which is a prerequisite for viral propagation. In addition, Hsp70 protein demonstrated strong interaction with host Angiotensin-converting enzyme 2 (ACE2) as well as the receptor binding domain (RBD) of the SARS-CoV-2 Spike protein, indicating that interaction of Hsp70 with ACE2 and Spike protein may serve to protect them during febrile conditions. Suppressive and prophylactic treatment of Vero E6 cells with Hsp70 inhibitor PES, 2-(3-chlorophenyl) ethynesulfonamide (PES-Cl), abrogated viral infection more potently than the currently used drug Remdesivir. In conclusion, our study not only provides a fundamental insight into the role of host Hsp70 in SARS-CoV-2 pathogenesis, it paves the way for development of potent and irresistible anti-viral therapeutics.

Exploring antiviral and antiparasitic activity of gold N-heterocyclic carbenes with thiolate ligands.

Gold(I) N-heterocyclic carbenes have been explored for their therapeutic potential against several diseases. Neglected tropical diseases, including leishmaniasis, Chagas disease, and viral infections, such as zika, mayaro, and chikungunya, urgently require new treatment options. The emergent SARS-CoV-2 also demands significant attention. Gold complexes have shown promise as alternative treatments for these conditions. Previously, gold(I)(1,3-bis(mesityl)imidazole-2-ylidene)Cl (AuIMesCl) demonstrated significant leishmanicidal and anti-Chikungunya virus activities. In this study, we synthesized and fully characterized a series of gold(I)(1,3-bis(mesityl)imidazole-2-ylidene)(SR) complexes, where SR includes thiolate donor species such as 1,3-thiazolidine-2-thione, 1,3-benzothiazole-2-thione, 2-mercaptopyrimidine, and 2-thiouracil. These compounds were stable in solution, and ligand exchange reactions with N-acetyl-L-cysteine indicated that complexes with SR ligands are more labile than those with chloride. Although the reactions are rapid, they reach equilibrium at varying molar ratios depending on the SR ligand. The increased lability of these compounds results in higher cytotoxicity to host cells, such as Vero E6 and bone marrow-differentiated macrophages, compared to AuIMesCl. Despite this, the compounds effectively inhibited viral replication, achieving 95.5% inhibition of Zika virus replication at 2 μM with 96% host cell viability. Although active at low concentrations (∼2 μM) against Leishmania (L.) amazonensis and Trypanosoma cruzi, their high cytotoxicity for macrophages confirmed AuIMesCl as a better candidate with a higher selectivity index. This work correlates the coordination chemistry of pyrimidines and thiazolidines with their in vitro biological activities against significant diseases.

Comparable Efficacy of Lopinavir/Ritonavir and Remdesivir in Reducing Viral Load and Shedding Duration in Patients with COVID-19.

The spread of COVID-19 has significantly increased research on antiviral drugs and measures such as case isolation and contact tracing. This study compared the effects of lopinavir/ritonavir and remdesivir on COVID-19 patients with a control group receiving no antiviral drugs. Patients confirmed to have a SARS-CoV-2 infection via real-time RT-PCR were divided into three groups: lopinavir/ritonavir, remdesivir, and control. We assessed the efficacy of these drugs in reducing viral load and viral shedding duration using real-time RT-PCR and Vero E6 cell cultures. Lopinavir/ritonavir led to no detectable infectious SARS-CoV-2, with a median viral clearance time of one day, whereas one remdesivir-treated case remained culture-positive until day 12. Lopinavir/ritonavir significantly reduced viral load compared to remdesivir and control groups (p = 0.0117 and p = 0.0478). No infectious virus was detected in the lopinavir/ritonavir group, and the non-infectious SARS-CoV-2 proportion remained constant at 90%, higher than in the remdesivir and control groups (p = 0.0097). There was a significant difference in culture positivity among the groups (p = 0.0234), particularly between the lopinavir/ritonavir and remdesivir groups (p = 0.0267). These findings suggest that lopinavir/ritonavir reduces viral load and shortens the viral shedding duration compared to remdesivir, despite not being an effective treatment option.

Prone-to-Infectivity of Omicron BA.2 Subvariant from Indonesia on ACE-2 Expressing Cell Lines

SARS-CoV-2 virus undergoes mutation, leading to the virus's evolution and modifications in the characteristics of the virus. Omicron, including BA.2 subvariant, is currently the predominant variant in SARS-CoV-2 infection. There are no reports regarding its properties or the utilization of BA.2 Indonesian isolate for therapy and vaccine development. Therefore, this study evaluated appropriate host cells for Omicron BA.2 Indonesian isolate via susceptibility tests. The Omicron BA.2 from Indonesia was exposed to three mammalian-ACE2-expressing cell lines. Sharing amino acids between BA.2 from Indonesia and previous VOC Omicron subvariants was performed using a simple in silico comparison method. The results showed that the virus could not infect HepG2 and Huh-7D12 due to no foci forming on those cell lines. Moreover, we also found that BA.2 Indonesian isolate has a unique amino acid alteration on spike protein. According to the findings, the Omicron BA.2 from Indonesia could propagate on Vero E6 cell lines, and the mutations could play a role in the virus's changing infection mechanism. A deeper in vitro and in silico experiment could enhance the findings by comparing all BA.2 sequences from Indonesia and analyzing the infection mechanism by each single mutation using pseudovirus.

Elevation of IL-8 secretion induced by PEDV infection via NF-κB signaling pathway.

Porcine epidemic diarrhea virus (PEDV) is associated with severe enteritis, which contributes to high mortality in piglets. The aim of this study was to describe molecular mechanisms associated with proinflammatory cytokine(s) production during PEDV infection. We showed that infection of porcine intestine epithelial cell clone J2 (IPEC-J2) with PEDV induces a gradual increase in interleukin 8 (IL-8) production at different time points, as well as infection of Vero E6 with PEDV. The secretion of IL-8 in these two cell lines infected with PEDV is related to the activation of NF-κB. Furthermore, the cells expressing PEDV M or E protein can induce the upregulation of IL-8. These findings suggest that the IL-8 production can be the initiator of inflammatory response by the host cells upon PEDV infection.

Exploring the therapeutic potential of Thai medicinal plants: in vitro screening and in silico docking of phytoconstituents for novel anti-SARS-CoV-2 agents

BackgroundThe high virulence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for coronavirus disease 2019 (COVID-19), has triggered global health and economic concerns. The absence of specific antiviral treatments and the side effects of repurposed drugs present persistent challenges. This study explored a promising antiviral herbal extract against SARS-CoV-2 from selected Thai medicinal plants based on in vitro efficacy and evaluated its antiviral lead compounds by molecular docking.MethodsTwenty-two different ethanolic-aqueous crude extracts (CEs) were rapidly screened for their potential activity against porcine epidemic diarrhea virus (PEDV) as a surrogate using a plaque reduction assay. Extracts achieving ≥ 70% anti-PEDV efficacy proceeded to the anti-SARS-CoV-2 activity test using a 50% tissue culture infectious dose method in Vero E6 cells. Molnupiravir and extract-free media served as positive and negative controls, respectively. Potent CEs underwent water/ethyl acetate fractionation to enhance antiviral efficacy, and the fractions were tested for anti-SARS-CoV-2 performance. The fraction with the highest antiviral potency was identified using liquid chromatography–high-resolution mass spectrometry (LC–HRMS). Molecular docking analyses of these compounds against the main protease (Mpro) of SARS-CoV-2 (6LU7) were performed to identify antiviral lead molecules. The top three hits were further evaluated for their conformational stability in the docked complex using molecular dynamics (MD) simulation.ResultsThe water fraction of mulberry (Morus alba Linn.) leaf CE (WF-MLCE) exhibited the most potent anti-SARS-CoV-2 efficacy with low cytotoxicity profile (CC50 of ~ 0.7 mg/mL), achieving 99.92% in pre-entry mode and 99.88% in postinfection treatment mode at 0.25 mg/mL. Flavonoids and conjugates were the predominant compounds identified in WF-MLCE. Molecular docking scores of several flavonoids against SARS-CoV-2 Mpro demonstrated their superior antiviral potency compared to molnupiravir. Remarkably, myricetin-3-O-β-D-galactopyranoside, maragrol B, and quercetin 3-O-robinobioside exhibited binding energies of ~ − 9 kcal/mol. The stability of each ligand–protein complex of these compounds with the Mpro system showed stability during MD simulation. These three molecules were pronounced as antiviral leads of WF-MLCE. Given the low cytotoxicity and high antiviral potency of WF-MLCE, it holds promise as a candidate for future therapeutic development for COVID-19 treatment, especially considering its economic and pharmacological advantages.