Vero Cells Research Articles

A Lassa virus live attenuated vaccine candidate that is safe and efficacious in guinea pigs

AbstractLassa virus (LASV) is a rodent-borne mammarenavirus that causes tens to hundreds of thousands of human infections annually in Western Africa. Approximately 20% of these infections progress to Lassa fever (LF), an acute disease with case–fatality rates from ≈20–70%. Currently, there are no approved vaccines or specific therapeutics to prevent or treat LF. The LASV genome consists of a small (S) segment that has two genes, GP and NP, and a large (L) segment that has two genes, L and Z. In both segments, the two genes are separated by non-coding intergenic regions (IGRs). Recombinant LASVs (rLASVs), in which the L segment IGR was replaced with the S segment IGR or in which the GP gene was codon-deoptimized, lost fitness in vitro, were highly attenuated in vivo, and, when used as vaccines, protected domesticated guinea pigs from otherwise lethal LASV exposure. Here, we report the generation of rLASV/IGR-CD, which includes both determinants of attenuation and further enhances the safety of the vaccine compared with its predecessors. rLASV/IGR-CD grew to high titers in Vero cells, which are approved for human vaccine production, but did not cause signs of disease or pathology in guinea pigs. Importantly, guinea pigs vaccinated with rLASV/IGR-CD were completely protected from disease and death after a typically lethal exposure to wild-type LASV. Our data support the development of rLASV/IGR-CD as a live-attenuated LF vaccine with stringent safety features.

Antibacterial, Antioxidant and Cytotoxicity Assessment of Crassocephalum crepidioides Leaf Extract

The goal of the present investigation was to demonstrate the antibacterial activity of different solvent extracts (methanol, ethanol, cold aqueous and hot aqueous) of Crassocephalum crepidioides against ATCC bacterial cultures of Staphylococcus aureus, Escherichia coli, Methicillin resistant Staphylococcus aureus, Pseudomonas aeruginosa and its antioxidant potential. Furthermore, the chemical constituents present in the extract was perused by Gas chromatography-mass spectroscopy (GC-MS), along with in vitro cytotoxicity assessment. All the extracts were shown to be sensitive against S. aureus, MRSA and P. aeruginosa except for the ethanolic extract which was resistant to P. aeruginosa. Of all the extracts, hot aqueous extract found to be the most effective. It was found that Minimum inhibitory concentration (MIC) value of hot aqueous extract against S. aureus, MRSA and P. aeruginosa were 5 mg/mL, 5 mg/mL and 40 mg/mL, respectively. DPPH results showed that C. crepidioides leaf extract has potent antioxidant activity with IC50 value of 57.9 µg/mL. 22 compounds were detected in hot aqueous extract through Gas chromatography-mass spectroscopy. The results of the cytotoxicity evaluation displayed that the IC50 value of the hot aqueous extract of C. crepidioides on Vero cell lines was 292 µg/mL. This study concludes that C. crepidioides leaf extract is non-toxic, has various bioactive components and strong antibacterial and antioxidant activities, thus making it a promising therapeutic agent for various biomedical applications.

Comparative efficacy of Knema retusa extract delivery via PEG-b-PCL, niosome, and their combination against Acanthamoeba triangularis genotype T4: characterization, inhibition, anti-adhesion, and cytotoxic activity

Background Acanthamoeba spp. is a waterborne, opportunistic protozoan that can cause amebic keratitis and granulomatous amebic encephalitis. Knema retusa is a native tree in Malaysia, and its extracts possess a broad range of biological activities. Niosomes are non-ionic surfactant-based vesicle formations and suggest a future targeted drug delivery system. Copolymer micelle (poly(ethylene glycol)-block-poly(ɛ-caprolactone); PEG-b-PCL) is also a key constituent of niosome and supports high stability and drug efficacy. To establish Knema retusa extract (KRe) loading in diverse nanocarriers via niosome, PEG-b-PCL micelle, and their combination and to study the effect of all types of nanoparticles (NPs) on Acanthamoeba viability, adherent ability, elimination of adherence, and cytotoxicity. Methods In this study, we characterized niosomes, PEG-b-PCL, and their combination loaded with KRe and tested the effect of these NPs on Acanthamoeba triangularis stages. KRe-loaded PEG-b-PCL, KRe-loaded niosome, and KRe-loaded PEG-b-PCL plus niosome were synthesized and characterized regarding particle size and charge, yield, encapsulation efficiency (EE), and drug loading content (DLC). The effect of these KRe-loaded NPs on trophozoite and cystic forms of A. triangularis was assessed through assays of minimal inhibitory concentration (MIC), using trypan blue exclusion to determine the viability. The effect of KRe-loaded NPs was also determined on A. triangularis trophozoite for 24–72 h. Additionally, the anti-adhesion activity of the KRe-loaded niosome on trophozoites was also performed on a 96-well plate. Cytotoxicity activity of KRe-loaded NPs was assessed on VERO and HaCaT cells using MTT assay. Results KRe-loaded niosome demonstrated a higher yielded (87.93 ± 6.03%) at 286 nm UV-Vis detection and exhibited a larger size (199.3 ± 29.98 nm) and DLC (19.63 ± 1.84%) compared to KRe-loaded PEG-b-PCL (45.2 ± 10.07 nm and 2.15 ± 0.25%). The EE (%) of KRe-loaded niosome was 63.67 ± 4.04, which was significantly lower than that of the combination of PEG-b-PCL and niosome (79.67 ± 2.08). However, the particle charge of these NPs was similar (−28.2 ± 3.68 mV and −28.5 ± 4.88, respectively). Additionally, KRe-loaded niosome and KRe-loaded PEG-b-PCL plus niosome exhibited a lower MIC at 24 h (0.25 mg/mL), inhibiting 90–100% of Acanthamoeba trophozoites which lasted 72 h. KRe-loaded niosome affected adherence by around 40–60% at 0.125–0.25 mg/mL and removed Acanthamoeba adhesion on the surface by about 90% at 0.5 mg/mL. Cell viability of VERO and HaCaT cells treated with 0.125 mg/mL of KRe-loaded niosome and KRe-loaded PEG-b-PCL plus niosome exceeded 80%. Conclusion Indeed, niosome and niosome plus PEG-b-PCL were suitable nanocarrier-loaded KRe, and they had a greater nanoparticle property to test with high activities against A. triangularis on the reduction of adherence ability and demonstration of its low toxicity to VERO and HaCaT cells.

Phytochemical Profiling by HPLC-ESI-MS/MS and InVitro Investigation of the Antidiabetic Activity of Cassia bakeriana Bark Extract and Fractions.

Type 2 diabetes mellitus is a global health problem, placing patients at a higher risk of developing cardiovascular diseases and cancer. This study investigates the antidiabetic potential of Cassia bakeriana bark extracts and fractions. We evaluate their ability to inhibit α-amylase and α-glucosidase enzymes and advanced glycation end-products (AGEs). The antioxidant potential was also examined. Extracts were prepared through maceration with hexane (HE) and ethanol (EE), and the fractions were obtained via liquid-liquid extraction from EE. Anti-enzymatic, anti-glycation, antioxidant, and cytotoxic assays were conducted in 96-well plates using different concentrations of samples to determine the half-maximal inhibitory concentration (IC50). Active samples were further analyzed using HPLC-(-)-ESI-MS/MS. The ethyl acetate fraction (EAF) demonstrated a high percentage of α-amylase inhibition (94.0%) with a promising IC50 value of 1.05 μg mL-1. Additionally, EAF displayed 61.5% inhibition of α-glucosidase, with an IC50 value of 537 μg mL-1. The EE, EAF, and n-butanol fraction (BF) exhibited strong anti-glycation capacities. Furthermore, the EE, EAF, BF, and dichloromethane fractions showed promising antioxidant activity using the DPPH and ORAC methodologies. Cytotoxic activity was also evaluated with Vero cells, revealing no adverse effects on cell viability (CC50 > 512.0 μg mL-1). Active samples predominantly comprised proanthocyanidins, flavonoids, and anthraquinone, representing the main constituents of C. bakeriana bark. This study provides the first assessment of the antidiabetic potential of C. bakeriana bark and a comprehensive analysis of the chemical composition of its active extracts and fractions, offering hope for future treatments.

Innovative anti-proliferative effect of the antiviral favipiravir against MCF-7 breast cancer cells using green nanoemulsion and eco-friendly assessment tools.

Telomerase enzyme prevents telomere shortening during division, having human telomerase reverse transcriptase (hTERT) as its catalytic subunit. Favipiravir (FAV), an RNA-dependent RNA polymerases inhibitor, shared structural similarity with hTERT and thus assumed to have cytotoxic effect on cancer cells, in addition to its prophylactic effect to immunocompromised cancer patients. Nanoemulsion (NE) is a potential tumor cells targeting delivery system, thereby enhancing therapeutic efficacy at the intended site, mitigating systemic toxicity, and overcoming multidrug resistance. The objective of this study is to develop a green FAV nanoemulsion (FNE) that is environmentally friendly and safe for patients, while aiming to enhance its cytotoxic effects. The study also highlights the environmental sustainability of the developed RP-HPLC method and assesses its greenness impact. The FNE formulation underwent thermodynamic stability testing and invitro characterization. Greenness was assessed using advanced selected tools like the Analytical Eco-Scale (AES), Analytical Greenness Metric for Sample Preparation (AGREEprep), and green analytical procedure index (GAPI). The cytotoxic potential of FNE was screened against MCF-7 breast cancer and Vero normal cell lines using SRB assay. Stable and ecofriendly FNE was formulated having a particle size (PS) of 25.29 ± 0.57nm and a zeta potential of -6.79 ± 5.52 mV. The cytotoxic effect of FNE on MCF-7 cells was more potent than FAV with lower IC50 while FNE showed non-toxic effect on VERO normal cell line. Therefore, the FAV nanoemulsion formulation showed targeted cytotoxicity on MCF-7 cells while being non-toxic on normal Vero cells.

AI Promoted Virtual Screening, Structure-Based Hit Optimization, and Synthesis of Novel COVID-19 S-RBD Domain Inhibitors.

Coronavirus disease 2019 (COVID-19) is caused by a new, highly pathogenic severe-acute-respiratory syndrome coronavirus 2 (SARS-CoV-2) that infects human cells through its transmembrane spike (S) glycoprotein. The receptor-binding domain (RBD) of the S protein interacts with the angiotensin-converting enzyme II (ACE2) receptor of the host cells. Therefore, pharmacological targeting of this interaction might prevent infection or spread of the virus. Here, we performed a virtual screening to identify small molecules that block S-ACE2 interaction. Large compound libraries were filtered for drug-like properties, promiscuity and protein-protein interaction-targeting ability based on their ADME-Tox descriptors and also to exclude pan-assay interfering compounds. A properly designed AI-based virtual screening pipeline was applied to the remaining compounds, comprising approximately 10% of the starting data sets, searching for molecules that could bind to the RBD of the S protein. All molecules were sorted according to their screening score, grouped based on their structure and postfiltered for possible interaction patterns with the ACE2 receptor, yielding 31 hits. These hit molecules were further tested for their inhibitory effect on Spike RBD/ACE2 (19-615) interaction. Six compounds inhibited the S-ACE2 interaction in a dose-dependent manner while two of them also prevented infection of human cells from a pseudotyped virus whose entry is mediated by the S protein of SARS-CoV-2. Of the two compounds, the benzimidazole derivative CKP-22 protected Vero E6 cells from infection with SARS-CoV-2, as well. Subsequent, hit-to-lead optimization of CKP-22 was effected through the synthesis of 29 new derivatives of which compound CKP-25 suppressed the Spike RBD/ACE2 (19-615) interaction, reduced the cytopathic effect of SARS-CoV-2 in Vero E6 cells (IC50 = 3.5 μM) and reduced the viral load in cell culture supernatants. Early in vitro ADME-Tox studies showed that CKP-25 does not possess biodegradation or liver metabolism issues, while isozyme-specific CYP450 experiments revealed that CKP-25 was a weak inhibitor of the CYP450 system. Moreover, CKP-25 does not elicit mutagenic effect on Escherichia coli WP2 uvrA strain. Thus, CKP-25 is considered a lead compound against COVID-19 infection.

Synthesis, antiviral activity against wild-type SARS-CoV-2 and molecular docking studies of new aryl(1,2-dithiolo[3,4-c]quinolin-1-ylidene)amines

Unlike most attempts to find compounds with activity against SARS-CoV-2 aimed at reusing approved drugs, our goal was to find compounds with antiviral activity among the 1,2-dithioloquinoline derivatives we synthesized. These compounds exhibit pleiotropic effects, having a novel structure compared to known pharmaceuticals. In this work, we diversified the structure of 1,2-dithioloquinoline by introducing various substituents (chlorine atom, ether, amide, sulfonamide groups, pharmacophore heterocycles) into different positions of this tricyclic framework. Using docking with further quantum chemical post-processing of calculations of the created virtual library of 404 structures, more than ten compounds of the aryl(4,4-dimethyl-4,5-dihydro-1H-[1,2]dithiolo[3,4-c]quinoline-1-ylidene)amine series were discovered, synthesized and experimentally studied. The bioactive screening of newly synthesized compounds revealed that six of them demonstrate suppression of SARS-CoV-2 replication in Vero E6 cell culture in the micromolar range of EC50 values (from 0.27 to 98.48 μM). The best compound, in the structure of which fragments of tricyclic dithioloquinoline and streptocide are combined, demonstrated a highest ability to protect Vero E6 cells from SARS-CoV-2 with EC50 = 0.27 μM, as well as low cytotoxicity with a selectivity index SI > 370, exceeding all reference values compounds used in the study (remdesivir, GC376, ML188).

Safety and immunogenicity of freeze-dried human rabies vaccines: A phase 3 clinical trial of Zagreb and Essen regimes

ABSTRACT Recently optimized freeze-dried rabies vaccines (Vero cell) are promising for rabies prevention; however, comparisons of Essen 5-dose and Zagreb 4-dose regimens are needed for clinical applications. This phase III clinical trial aimed to assess the safety and immunogenicity of candidate freeze-dried rabies vaccines developed for human use by Shandong Yeedo Biotechnology (Registration No.: CTR20182016, http://www.chinadrugtrials.org.cn/index.html). In total, 40 participants in stage I and 1797 subjects in stage II with an age range of 10–60 years were recruited. Both 4-dose and 5-dose experimental vaccines were well-tolerated in stage 1, with similar overall adverse event (AE) rates. In stage 2, systemic fever (35.39%) and local pain (48.91%) were common, and the rate of Grade 3 AEs was approximately 2.5%. Rates of local reactions and unsolicited AEs differed among groups (p = .045 and 0.011). Immunogenicity analyses showed higher antibody levels, seroconversion rates, and pre-immune seroconversion rates in the 4-dose experimental group versus the 5-dose group (p < .001) on day 7 post-first dose, with similar GMCs (geometric mean concentrations) by day 14. Pre-immune negative subjects had comparable antibody levels in the 4-dose and 5-dose experimental groups, outperforming the 5-dose control group (p = .039). The rate difference (95% CI) for first-dose seroconversion at 14 days post-vaccination among pre-immune antibody-negative subjects indicated non-inferiority between the 5-dose experimental and control groups. Overall, the Shandong Yeedo rabies vaccine demonstrated satisfactory safety and efficacy, offering a new option for rabies prevention.

Randomized Clinical Trials Demonstrate the Safety Assessment of Alkalihalobacillus clausii AO1125 for Use as a Probiotic in Humans

(1) Background: Alkalihalobacillus clausii AO1125 is a Gram-positive, motile, spore-forming bacterium with potential as a probiotic due to its broad-spectrum antimicrobial activity, inhibiting pathogens like Listeria monocytogenes, Staphylococcus aureus, and Clostridium difficile, as well as anti-rotavirus activity. Its resilience in gastrointestinal conditions suggests benefits for gut health. This study evaluates the safety and probiotic potential of A. clausii AO1125. (2) Methods: Genome annotation identified genes linked to probiotic traits such as stress resistance, gut colonization, immune modulation, and antimicrobial production. The genome was screened for antibiotic resistance genes using CARD, bacteriocin clusters using BAGEL4, and virulence factors via VFDB. Cytotoxicity was assessed on Vero cells and erythrocytes, and a Phase I, double-blind, placebo-controlled clinical trial was conducted with 99 healthy volunteers (50 AO1125, 49 placebo). (3) Results: Genomic analysis confirmed minimal antibiotic resistance genes and the absence of virulence factors, supporting safety. A. clausii AO1125 showed no pathogenicity, cytotoxicity, or hemolytic activity and was well-tolerated in clinical settings, with mild, transient abdominal gas as the most common adverse event. (4) Conclusions: The safety profile and genetic basis for probiotic and antimicrobial properties support A. clausii AO1125 as a promising probiotic candidate for gastrointestinal health, warranting further clinical research.

MPXV infection impairs IFN response but is partially sensitive to IFN-γ antiviral effect.

The recent outbreak of monkeypox virus (MPXV) has caused global concern. How the virus evades the interferon (IFN) response is still poorly understood. We analyzed type I/II IFN (IFN-I/II) expression in clinical samples from MPXV-infected patients and measured IFN-I kinetics in MPXV-infected cells. We also evaluated the anti-MPXV activity of IFN-I/II in A549, HeLa and Vero-E6 cell lines. IFN-I/II mRNA expression was detected in skin lesions, anal swabs, nasopharyngeal samples and peripheral blood mononuclear cells (PBMC), with the highest levels in skin lesions (p < 0.05). High MPXV DNA levels in clinical samples were associated with increased IFN-I levels. In vitro, MPXV infection induced a peak of IFN-I between 48 and 72h post-infection (p < 0.01). Pre-treatment of the A549, HeLa and Vero-E6 cells with high concentrations (≥ 100,000 International Unit, IU/ml) of IFN-α and IFN-ω did not inhibit or had little effect on MPXV replication, while IFN-β moderately reduced MPXV replication by 2.7-1.5 log10 at 100,000 IU/ml. In clinical samples there was a trend for elevated levels of IFN-γ in association with lower MPXV load and in vitro IFN-γ (3,600 IU/ml) strongly reduced viral titers by 3.4-1.6 log10. There were no significant differences in expression of select IFN-stimulated genes (ISGs) in MPXV infection in vitro. This study shows that MPXV delays IFN-I induction and inhibits expression of selected ISGs in vitro and is associated with an IFN-I resistance phenotype in vivo. However, MPXV is less resistant to IFN-γ in vivo and is sensitive to IFN-γ treatment in vitro, suggesting a potential therapeutic role for IFN-γ.

Combined effect of basic antiherpetic drugs with a new inhibitor of the terminase complex of herpes simplex virus type 1 in Vero cell culture

More than 90% of the world’s population are carriers of herpes simplex virus type 1 (HSV-1). The infection manifests itself in the formation of blisters and ulcers on the face or genitals, and can cause blindness, encephalitis, and generalized infection. All modern first- and second-line antiherpetic drugs selectively inhibit viral DNA-polymerase. The purine-benzoxazine conjugate LAS-131 [(S)-4-[6-(purin-6-yl)aminohexanoyl]-7,8-difluoro-3,4-dihydro-3-methyl-2H-[1,4]benzoxazine], which we described earlier, uses the large subunit of the HSV-1 terminase complex as a biotarget and selectively inhibits its reproduction in vitro. For the first time, we have obtained fundamentally new results on the combined effect of LAS-131 on human herpesvirus infection with practically significant antiviral compounds – nucleoside analogues (acyclovir [ACV], penciclovir [PCV], ganciclovir [GCV], brivudine [BVDU], iododeoxyuridine [IDU], adenine arabinoside [Ara-A], as well as a nucleoside phosphonate analogue (cidofovir [CDV]) and a pirophosphate analogue (foscarnet [FOS]). Using a inhibition assay of cytopathic effect (CPE) induced by a virus, it was shown that when combined with LAS-131, the concentrations of the compounds in combinations providing inhibition of HSV-1-induced CPE by 50%, decreased by 2 times (additive effect, FOS) or more (synergistic effect, ACV, PCV, GCV, IDU, BVDU, Ara-A, CDV). Reducing the concentrations of agents creates non-permissive conditions for the reproduction of HSV-1 and opens up new real possibilities for controlling human herpesvirus infection.

Endogenous ZAP is associated with altered Zika virus infection phenotype

The zinc finger antiviral protein 1 (ZAP) has broad antiviral activity. ZAP is an interferon (IFN)-stimulated gene, which itself may enhance type I IFN antiviral response. In a previous study, Zika virus was identified as ZAP-resistant and not sensitive to ZAP antiviral activity. Here, we found that ZAP was associated with the inhibition of Zika virus in Vero cells, in the absence of a robust type I IFN system because Vero cells are deficient for IFN-alpha and -beta. Also, quantitative RNA-seq data indicated that endogenous ZAP is associated with altered global gene expression both in the steady state and during Zika virus infection. Further studies are warranted to elucidate this IFN-alpha and -beta independent anti-Zika virus activity and involvement of ZAP.

Evaluation of the effectiveness of chemical inactivation and immunogenicity of the Omicron variant of the SARS-CoV-2 virus

The rapid spread of coronavirus infection COVID-19 among the population of many countries around the world has contributed to the emergence of many genetic variants of SARS-CoV-2. Compared to previous coronavirus variants, the new Omicron variants have shown a noticeable degree of mutation. Virus inactivation is one of the most important steps in the development of inactivated vaccines. The chemical inactivation agents currently used are β-propiolactone and formaldehyde, but there is no uniform standard for designing and specifying the inactivation process. Evaluation and comparison of the effectiveness of chemical inactivation of two agents, formaldehyde and β-propiolactone against immunogenicity of the Omicron variant of the SARS-CoV-2 virus. Nasopharyngeal swabs were used to obtain the SARS-CoV-2 Omicron variant virus. Vero cell culture was used to isolate, reproduce, titrate the virus, and perform a neutralization reaction. The kinetics of studying the inactivation of the virus by chemical agents such as formaldehyde and β-propiolactone was carried out. Studies have been conducted to comparatively evaluate the effectiveness of chemical agents used to inactivate the SARS-CoV-2 virus of the Omicron variant, planned for use in the production of an inactivated whole-virion vaccine. Formaldehyde and β-propiolactone were used as inactivation agents in concentrations of 0.05, 0.1, 0.5% of the total volume of the virus suspension. It has been established that complete inactivation of the virus by formaldehyde in the concentrations used at a temperature of 37 °C occurs within up to 2 hours, and when using beta-propiolactone, within up to 12 hours. Inactivated virus samples have different antigenic activity depending on the concentration of the inactivation agents used. The most pronounced antigenic activity is manifested in samples of the pathogen that were treated with an inactivation agent at a mild concentration of 0.05%. Increasing the concentration of inactivation agent by 5 or more times leads to a significant decrease in the antigenicity of the SARS-CoV-2 virus. With the inactivation modes used, the loss of biological activity of the virus occurs faster and antigenicity is retained largely when treated with formaldehyde.

Synthesis and evaluation of fluorinated piperazine-hydroxyethylamine analogues as potential antiplasmodial candidates.

In this manuscript, twenty-one novel fluorinated piperazine-hydroxyethylamine analogues were synthesized and tested against Plasmodium falciparum (Pf). Among tested compounds, two 13g and 14g exhibited promising inhibitory activity on Pf3D7 withIC50 values of 0.28 and 0.09 µM, respectively. Neither of the hits exhibited cytotoxicity on HepG2 cells up to 150 µM and Vero cells up to 20 µM. Compounds 13g and 14g were also evaluated against chloroquine-resistant PfDd2 and displayed IC50 values of 0.11 and 0.10 µM, respectively. Next, 13g and 14g were administered to the Plasmodium berghei mice model at 30mg/kg intraperitoneally for four consecutive doses, which showed 25% and 50% reduction in the parasitemia load, respectively. The efficacy of hits 13g and 14g was improved along with mean survival time when administered in combination with artesunate. On liver-stage parasites, compounds 13g and 14g showed >90% inhibition at 1µM. Compound 14g was also tested for toxicity in mice at 100 mg/kg dose, which revealed no abnormality in mice organs. Preliminary pharmacokinetic studies of compound 14g exhibited absorption and maintained a presence in the body for more than six hours.

Sunflower Trypsin Monocyclic Inhibitor Selected for the Main Protease of SARS-CoV-2 by Phage Display.

Main protease (Mpro), also known as 3-chymotrypsin-like protease (3CLpro), is a nonstructural protein (NSP5) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) responsible for the cleavage of virus polyproteins during viral replication at 11 sites, which generates 12 functional proteins. Mpro is a cysteine protease that presents specificity for the amino acid residue glutamine (Gln) at the P1 position of the substrate. Due to its essential role in processing the viral polyprotein for viral particle formation (assembly), Mpro inhibition has become an important tool to control coronavirus disease 2019 (COVID-19), since Mpro inhibitors act as antivirals. In this work, we proposed to identify specific inhibitors of the Mpro of SARS-CoV-2 using a monocyclic peptide (sunflower trypsin inhibitor (SFTI)) phage display library. Initially, we expressed, purified and activated recombinant Mpro. The screening of the mutant SFTI phage display library using recombinant Mpro as a receptor resulted in the five most frequent SFTI mutant sequences. Synthetized mutant SFTIs did not inhibit Mpro protease using the fluorogenic substrate. However, the mutant SFTI 4 efficiently decreased the cleavage of recombinant human prothrombin as a substrate by Mpro, as confirmed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE). Additionally, SFTI 4 presented a dissociation constant (KD) of 21.66 ± 6.66 µM for Mpro by surface plasmon resonance. Finally, 0.1 µM SFTI 4 reduced VERO cell infection by SARS-CoV-2 wt after 24 and 48 h. In conclusion, we successfully screened a monocyclic peptide library using phage display for the Mpro of SARS-CoV-2, suggesting that this methodology can be useful in identifying new inhibitors of viral enzymes.

Safety, immunogenicity and immune-persistence of a lyophilized human rabies vaccine (Vero cells) under Zagreb and Essen regimens: a randomized, open-label, controlled phase III clinical trial in healthy participants aged 10–60 years in China

Safety, immunogenicity and immune-persistence of a lyophilized human rabies vaccine (Vero cells) under Zagreb and Essen regimens: a randomized, open-label, controlled phase III clinical trial in healthy participants aged 10–60 years in China

Production of Oncolytic Measles Virus in Vero Cells: Impact of Culture Medium and Multiplicity of Infection

Oncolytic measles virus (MeV) is a promising anti-cancer treatment. However, the production of high titers of infectious MeV (typically 107–109 TCID50 per dose) is challenging because the virus is unstable under typical production conditions. The objective of this study was to investigate how the multiplicity of infection (MOI) and different media—a serum-containing medium (SCM), a serum-free medium (SFM) and two chemically defined media (CDM)—affect MeV production. We infected Vero cells at MOIs of 0.02, 0.2 or 2 TCID50 mL−1 and the lowest MOI resulted in the largest number of infected cells towards the end of the production period. However, this did not equate to higher maximum MeV titers, which were similar for all the MOIs. The medium had a moderate effect, generating maximum titers of 0.89–2.17 × 106, 1.08–1.25 × 106 and 4.58–9.90 × 105 TCID50 mL−1 for the SCM, SFM and CDM, respectively. Infection at a low MOI often required longer process times to reach maximum yields. On the other hand, a high MOI requires a large amount of MeV stock. We would therefore recommend a mid-range MOI of 0.2 TCID50 mL−1 for MeV production. Our findings show that SCM, SFM and CDM are equally suitable for MeV production in terms of yield and process time. This will allow MeV production in serum-free conditions, addressing the safety risks and ethical concerns associated with the use of serum.

CRISPR/Cas9 screens identify key host factors that enhance rotavirus reverse genetics efficacy and vaccine production

Rotaviruses pose a significant threat to young children. To identify novel pro- and anti-rotavirus host factors, we performed genome-wide CRISPR/Cas9 screens using rhesus rotavirus and African green monkey cells. Genetic deletion of either SERPINB1 or TMEM236, the top two antiviral factors, in MA104 cells increased virus titers in a rotavirus strain independent manner. Using this information, we optimized the existing rotavirus reverse genetics systems by combining SERPINB1 knockout MA104 cells with a C3P3-G3 helper plasmid. We improved the recovery efficiency and rescued several low-titer rotavirus reporter and mutant strains that prove difficult to rescue otherwise. Furthermore, we demonstrate that TMEM236 knockout in Vero cells supported higher yields of two live-attenuated rotavirus vaccine strains than the parental cell line and represents a more robust vaccine-producing cell substrate. Collectively, we developed a third-generation optimized rotavirus reverse genetics system and generated gene-edited Vero cells as a new substrate for improving rotavirus vaccine production.

Bacterial Cellulose–Silk Hydrogel Biosynthesized by Using Coconut Skim Milk as Culture Medium for Biomedical Applications

In this study, hydrogel films of biocomposite comprising bacterial cellulose (BC) and silk (S) were successfully fabricated through a simple, facile, and cost-effective method via biosynthesis by Acetobacter xylinum in a culture medium of coconut skim milk/mature coconut water supplemented with the powders of thin-shell silk cocoon (SC). Coconut skim milk/mature coconut water and SC are the main byproducts of coconut oil and silk textile industries, respectively. The S/BC films contain protein, carbohydrate, fat, and minerals and possess a number of properties beneficial to wound healing and tissue engineering, including nontoxicity, biocompatibility, appropriate mechanical properties, flexibility, and high water absorption capacity. It was demonstrated that silk could fill into a porous structure and cover fibers of the BC matrix with very good integration. In addition, components (fat, protein, etc.) in coconut skim milk could be well incorporated into the hydrogel, resulting in a more elastic structure and higher tensile strength of films. The tensile strength and the elongation at break of BC film from coconut skim milk (BCM) were 212.4 MPa and 2.54%, respectively, which were significantly higher than BC film from mature coconut water (BCW). A more elastic structure and relatively higher tensile strength of S/BCM compared with S/BCW were observed. The films of S/BCM and S/BCW showed very high water uptake ability in the range of 400–500%. The presence of silk in the films also significantly enhanced the adhesion, proliferation, and cell-to-cell interaction of Vero and HaCat cells. According to multiple improved properties, S/BC hydrogel films are high-potential candidates for application as biomaterials for wound dressing and tissue engineering.

Enzyme (α-Glucosidase, α-Amylase, PTP1B &amp; VEGFR-2) Inhibition and Cytotoxicity of Fluorinated Benzenesulfonic Ester Derivatives of the 5-Substituted 2-Hydroxy-3-nitroacetophenones

The prevalence of small multi-target drugs containing a fluorinated aromatic moiety among approved drugs in the market is due to the unique properties of this halogen atom. With the aim to develop potent antidiabetic agents, a series of phenylsulfonic esters based on the conjugation of the 5-substituted 2-hydroxy-3-nitroacetophenones 1a–d with phenylsulfonyl chloride derivatives substituted with a fluorine atom or fluorine-containing (-CF3 or -OCF3) group were prepared. Their structures were characterized using a combination of spectroscopic techniques complemented with a single-crystal X-ray diffraction (XRD) analysis on a representative example. The compounds were, in turn, assayed for inhibitory effect against α-glucosidase, α-amylase, protein tyrosine phosphatase 1 B (PTP1B) and the vascular endothelial growth factor receptor-2 (VEGFR-2) all of which are associated with the pathogenesis and progression of type 2 diabetes mellitus (T2DM). The antigrowth effect of selected compounds was evaluated on the human breast (MCF-7) and lung (A549) cancer cell lines. The compounds were also evaluated for cytotoxicity against the African Green Monkey kidney (Vero) cell line. The results of an in vitro enzymatic study were augmented by molecular docking (in silico) analysis. Their ADME (absorption, distribution, metabolism and excretion) properties have been evaluated on the most active compounds against α-glucosidase and/or α-amylase to predict their drug likeness.