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Discovery of the potent covalent inhibitor with an acrylate warhead for SARS-CoV-2 3CL protease.

COVID-19 has caused severe consequences in terms of public health and economy worldwide since its outbreak in December 2019. SARS-CoV-2 3C-l … with an acrylate warhead displayed potent activity against HCoV-OC43 (EC50 = 97 nM) and SARS-CoV-2 replicon (EC50 = 45 nM) and low cytotoxicity (CC50 > 10 μM) in Huh7 cells. Taken together, this study devised two series of 3CLpro inhibitors and provided the potent SARS-CoV-2 3CLpro inhibitor (12b) which may be used for treating coronavirus infections.

Вирус везикулярного стоматита в качестве платформы для измерения активности протекционистов.

Ингибиторы протеинов являются одними из самых мощных антивирусных препаратов. Они успешно применяются против таких вирусов, как вирус иммунодефицита человека (ВИЧ), вирус гепатита С (ГХВ) и острый острый респираторный синдром коронавирус 2 (SARS-COV-2). Поэтому для выявления ингибиторов, способных стать антивирусными препаратами, важное значение имеют средства скрининга ингибиторов. В этой статье мы описываем недавно разработанные клеточные и вирусные платформы для проверки ингибиторов. Мы разработали методы, представленные здесь путем генетически модифицирующего вирус сосудистого стоматита, м

Совпадение в аннотации оригинала
Protease inhibitors are among the most powerful antiviral drugs. They have been used successfully against viruses, such as the human immunod … e potential to become antiviral drugs. In this article, we describe newly developed cell- and virus replicon-based platforms to screen inhibitors. We developed the methods presented here by genetically modifying vesicular stomatitis virus, a model virus from the family Rhabdoviridae. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LL …

Intranasal delivery of replicating mRNA encoding hACE2-targeting antibody against SARS-CoV-2 Omicron infection in the hamster.

The Omicron variant is sweeping the world, which displays striking immune escape potential through mutations at key antigenic sites on the s … limited by the time-consuming process and the relative high cost. Here, we utilized a modified VEEV replicon with two subgenomic (sg) promoters engineered to express the light and heavy chains of the 3E8 mAb. The feasibility and protective efficacy of replicating mRNA encoding 3E8 against Omicron infection in the hamster were demonstrated through the lung …

CD8+ T cells mediate protection against Zika virus induced by an NS3-based vaccine.

Zika virus (ZIKV) is associated with congenital malformations in infants born to infected mothers, and with Guillain-Barré syndrome in infected adults. Development of ZIKV vaccines has focused predominantly on the induction of neutralizing antibodies, although a suboptimal antibody response may theoretically enhance disease severity through antibody-dependent enhancement (ADE). Here, we report induction of a protective anti-ZIKV CD8+ T cell response in the HLA-B*0702 Ifnar1-/- transgenic mice using an alphavirus-based replicon RNA vaccine expressing ZIKV nonstructural protein NS3, a potent T c…

Emergent multidrug-resistant nontyphoidal Salmonella serovars isolated from poultry in Brazil coharboring blaCTX-M-2 and qnrB or blaCMY-2 in large plasmids.

The number of foodborne gastroenteritis caused by nontyphoidal Salmonella (NTS) worldwide is estimated to be 80.3 million each year. Current … solates. All resistance genes were harbored in large plasmids, ranging from 30 to 270 kb. The pColE replicon was present in 8 MDR isolates; however it was not associated with resistance. ISCR1 and class I integron structures were always associated with blaCTX-M-2.

The hepatitis C viral nonstructural protein 5A stabilizes growth-regulatory human transcripts.

Numerous mammalian proto-oncogene and other growth-regulatory transcripts are upregulated in malignancy due to abnormal mRNA stabilization. In hepatoma cells expressing a hepatitis C virus (HCV) subgenomic replicon, we found that the viral nonstructural protein 5A (NS5A), a protein known to bind to viral RNA, also bound specifically to human cellular transcripts that encode regulators of cell growth and apoptosis, and this binding correlated with transcript stabilization. An important subset of human NS5A-target transcripts contained GU-rich elements, sequences known to destabilize mRNA. We fo…

Evaluation of an African swine fever (ASF) vaccine strategy incorporating priming with an alphavirus-expressed antigen followed by boosting with attenuated ASF virus.

In this study, an alphavirus vector platform was used to deliver replicon particles (RPs) expressing African swine fever virus (ASFV) antigens to swine. Alphavirus RPs expressing ASFV p30 (RP-30), p54 (RP-54) or pHA-72 (RP-sHA-p72) antigens were constructed and tested for expression in Vero cells and for immunogenicity in pigs. RP-30 showed the highest expression in Vero cells and was the most immunogenic in pigs, followed by RP-54 and RP-sHA-p72. Pigs primed with two doses of the RP-30 construct were then boosted with a naturally attenuated ASFV isolate, OURT88/3. Mapping of p30 identified an…

The coronavirus nucleocapsid protein is ADP-ribosylated.

ADP-ribosylation is a common post-translational modification, although how it modulates RNA virus infection is not well understood. While sc … n cells exogenously expressing N protein by transduction using Venezuelan equine encephalitis virus replicon particles (VRPs). However, plasmid-derived N protein was not ADP-ribosylated following transient transfection but was ADP-ribosylated after MHV infection, indicating that this modification requires virus infection. In conclusion, we have identified …

FR171456 is a specific inhibitor of mammalian NSDHL and yeast Erg26p.

FR171456 is a natural product with cholesterol-lowering properties in animal models, but its molecular target is unknown, which hinders furt … based on a model of Erg26. Finally, we show that FR171456 inhibits an artificial Hepatitis C viral replicon, and has broad antifungal activity, suggesting potential additional utility as an anti-infective. The discovery of the target and binding site of FR171456 within the target will aid further development of this compound.

Discovery of BI 207524, an indole diamide NS5B thumb pocket 1 inhibitor with improved potency for the potential treatment of chronic hepatitis C virus infection.

The development of interferon-free regimens for the treatment of chronic HCV infection constitutes a preferred option that is expected in th … or to demonstrate antiviral activity in genotype 1 HCV infected patients, BILB 1941 (1). Cell-based replicon potency was significantly improved through electronic modulation of the pKa of the carboxylic acid function of the lead molecule. Subsequent ADME-PK optimization lead to 27, a predicted low clearance compound in man. The preclinical profile of inhib …

Characterization of CTX-M-type extended-spectrum beta-lactamase-producing diarrheagenic Escherichia coli isolates in the Republic of Korea during 2008-2011.

To characterize the extended-spectrum beta-lactamases (ESBLs) in diarrheagenic Escherichia coli from Korea in 2008-2011, we screened seven enterotoxigenic E. coli (ETEC) and one enteroaggregative E. coli (EAEC) that produce ESBLs from a nationwide survey. All eight isolates produced CTX-M-type ESBLs, including CTX-M-12 (n = 4), CTX-M-14 (n = 2), and CTX-M-15 (n = 2). PCR-based replicon typing indicated that the blaCTX-M-12 genes of four ETEC isolates were carried on a conjugative IncF plasmid, whereas the blaCTX-M-14 of one EAEC was located on an IncK plasmid. This is the first report of the o…

Detection of antibiotic residues and association of cefquinome residues with the occurrence of Extended-Spectrum β-Lactamase (ESBL)-producing bacteria in waste milk samples from dairy farms in England and Wales in 2011.

Waste milk samples from 103 farms in England and Wales were examined for the presence of β-lactam antibiotics and ESBL-producing Enterobacteriaceae. Approximately 10 months after the initial sampling, further waste milk, environmental and faecal samples from farms shown to be positive for CTX-M Escherichia coli were investigated further. Isolates with an ESBL phenotype were tested by PCR for the presence of blaCTX-M, blaOXA, blaSHV and blaTEM genes. Isolates positive for blaCTX-M were sequenced to determine CTX-M type. Representative isolates were further examined by PFGE, plasmid replicon typ…

Discovery and early development of TMC647055, a non-nucleoside inhibitor of the hepatitis C virus NS5B polymerase.

Structure-based macrocyclization of a 6-carboxylic acid indole chemotype has yielded potent and selective finger-loop inhibitors of the hepatitis C virus (HCV) NS5B polymerase. Lead optimization in conjunction with in vivo evaluation in rats identified several compounds showing (i) nanomolar potency in HCV replicon cells, (ii) limited toxicity and off-target activities, and (iii) encouraging preclinical pharmacokinetic profiles characterized by high liver distribution. This effort culminated in the identification of TMC647055 (10a), a nonzwitterionic 17-membered-ring macrocycle characterized b…

Inhibition of HCV by the serpin antithrombin III.

BACKGROUND: Although there have been dramatic strides made recently in the treatment of chronic hepatitis C virus infection, interferon-α based therapy remains challenging for certain populations, including those with unfavorable IL28B genotypes, psychiatric co-morbidity, HIV co-infection, and decompensated liver disease. We have recently shown that ATIII, a serine protease inhibitor (serpin), has broad antiviral properties. RESULTS: We now show that ATIII is capable of inhibiting HCV in the OR6 replicon model at micromolar concentrations. At a mechanistic level using gene-expression arrays, …

Role of dendritic cell targeting in Venezuelan equine encephalitis virus pathogenesis.

The initial steps of Venezuelan equine encephalitis virus (VEE) spread from inoculation in the skin to the draining lymph node have been characterized. By using green fluorescent protein and immunocytochemistry, dendritic cells in the draining lymph node were determined to be the primary target of VEE infection in the first 48 h following inoculation. VEE viral replicon particles, which can undergo only one round of infection, identified Langerhans cells to be the initial set of cells infected by VEE directly following inoculation. These cells are resident dendritic cells in the skin, which mi…

Fragile X expression in thymidine-prototrophic and auxotrophic human-mouse somatic cell hybrids under low and high thymidylate stress conditions.

Expression of the fragile X site fra(X)(q27.3) was studied in thymidine-prototrophic and auxotrophic human-mouse somatic cell hybrids. In th … expression is an intrinsic property of the fragile site itself, which is believed to be composed of replicon clusters with pyrimidine-rich DNA sequence(s).

Functional analysis of the tick-borne encephalitis virus cyclization elements indicates major differences between mosquito-borne and tick-borne flaviviruses.

The linear, positive-stranded RNA genome of flaviviruses is thought to adopt a circularized conformation via interactions of short complemen … ces between mosquito-borne and tick-borne flaviviruses has practical implications for the design of replicons in vaccine and vector development.

Dynamics of the IncW genetic backbone imply general trends in conjugative plasmid evolution.

Plasmids cannot be understood as mere tools for genetic exchange: they are themselves subject to the forces of evolution. Their genomic and phylogenetic features have been less studied in this respect. Focusing on the IncW incompatibility group, which includes the smallest known conjugative plasmids, we attempt to unveil some common trends in plasmid evolution. The functional modules of IncW genetic backbone are described, with emphasis on their architecture and relationships to other plasmid groups. Some plasmid regions exhibit strong phylogenetic mosaicism, in striking contrast to others of

In Vitro Inhibition of Alphaviruses by Lycorine.

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus. As an emerging virus, CHIKV imposes a threat to public health. Currently, there ar … unctions at an early post-entry stage of CHIKV life cycle. The results based on two different CHIKV replicons provided further evidence that lycorine exerts its antiviral activity mainly by inhibiting CHIKV translation. Overall, our study extends the antiviral spectrum of lycorine.

Reverse Genetic Approaches for the Generation of Recombinant Zika Virus.

Zika virus (ZIKV) is an emergent mosquito-borne member of the Flaviviridae family that was responsible for a recent epidemic in the Americas … o date, for the generation of rZIKVs and the applications of these platforms for the development of replicon systems or reporter-expressing viruses.