Comparative screening of anti-dengue activity in aqueous and ethanol extracts of mangrove plants from Sabah

Aims@#Dengue virus is a global pathogen that lacks an effective vaccine or therapy. Screening medicinal plants for anti-dengue properties provides a promising avenue to identify potent compounds. Mangroves, known for their resilience in harsh conditions, produce a diverse range of natural products with unique biochemical profiles, which hold potential for anti-dengue treatments. This study aims to evaluate the anti-dengue activity of selected mangrove plant species from Sabah against DENV2 NS2B-NS3pro, utilizing an enzymatic protease assay. @*Methodology and results @#Six mangrove species (Avicennia marina, Bruguiera gymnorrhiza, Ceriops tagal, Rhizophora apiculata, Rhizophora mucronata and Xylocarpus granatum) were investigated, with various plant parts subjected to aqueous and ethanol extraction. The results demonstrated significant anti-dengue activity in both aqueous and ethanolic extracts of the mangroves against DENV2 NS2B-NS3pro, with IC50 values ranging from 0.95 µg/mL to 6.24 µg/mL. Notably, the ethanolic extract of R. apiculata leaves exhibited the highest inhibition, with an IC50 value of 0.95 µg/mL. @*Conclusion, significance and impact of study@#These findings suggest that the ethanolic extracts from R. apiculata leaves hold promise as potential candidates for dengue treatment. This study underscores the importance of natural products as valuable sources for the development of novel anti-dengue treatments, highlighting the need to explore mangroves in the quest for effective therapeutic options.

Optimization of expression conditions of dengue virus NS2B-NS3 protease in E.coli and determination of enzyme activity / 中国生物制品学杂志

@#Objective To express dengue virus(DENV)NS2B-NS3 protease in E.coli,optimize the expression conditions and determine the enzyme activity,so as to lay a foundation of screening and discovering of lead compounds targeting DENV.Methods Codon-optimized NS2B-NS3 gene was inserted into pET-28a vector to construct recombinant prokaryotic expression plasmid pET-28a-NS2B-NS3,which was transformed E.coli Rosetta(DE3)competent cells and induced by IPTG to express NS2B-NS3 protease. The optimal expression conditions of NS2B-NS3 protease in E.coli were determined by optimizing induction length,induction temperature and IPTG concentration. NS2B-NS3 protease was isolated and purified by HisTrap~(TM) affinity chromatography column and measured for the protease activity by fluorescence resonance energy transfer(FRET)assay.Results The recombinant prokaryotic expression plasmid pET-28a-NS2B-NS3 was constructed correctly as identified by restriction analysis(NheⅠ/XhoⅠ)and sequencing. The optimal expression conditions of NS2BNS3 protease in E.coli were as follows:induction temperature of 20 ℃,induction length of 10 h and IPTG concentration of0. 2 mmol/L. The purified NS2B-NS3 protease showed a purity of more than 90% with a exhibited a of 20 mg/L,which bound to mouse monoclonal antibody against His-tag specifically and had good hydrolytic activity with a specific activity of 16. 111 U/mg,a K_m of 16. 46 μmol/L and a k_(cat) of 0. 028/s.Conclusion DENV NS2B-NS3 protease with high purity and activity was successfully prepared,which laid an experimental foundation of the establishment of high-throughput screening model for inhibitors targeting NS2B-NS3 protease.

Bixinoids Derived from Bixa orellana as a Potential Zika Virus Inhibitor Using Molecular Simulations. Antiviral Effect on the Zika Virus of Bixinoids

Abstract Zika fever is a viral infection of great relevance in public health, especially in tropic regions, in which there is a predominance of mosquitoes of the genus Aedes, vectors of the disease. Microcephaly in neonatal children and Guillain-Barré syndrome in adults can be caused by the action of the Zika virus (ZIKV). Non-structural proteins, such as NS2B, NS3 and NS5, are important pharmacological targets, due to their action in the life cycle. The absence of anti-Zika drugs raises new research, including prospecting for natural products. This work investigated the in silico antiviral activity of bixin and six other derived molecules against the Zika viral proteins NS2B-NS3 and NS5. The optimized structure was subjected to molecular docking to characterize the interaction between bixinoids and ZIKV non-structural proteins, where significant interactions were observed with amino acid residues in the catalytic site in each enzyme. These results suggest that bixin and ethyl bixin has the potential to interfere with the enzymatic activity of NS2B, NS3 and NS5, thus being an indication of being a promising anti-Zika agent.

Advances in the release mechanisms of bluetongue virus / 生物工程学报

Bluetongue virus (BTV) causes Bluetongue (BT) of ruminants vectored by culicoides midges. It is also a classic model for studying the release mechanism of non-enveloped virus. This review begins with the infection and assembly of BTV, then summarizes the advances of different ways of releasing BTV. This includes BTV-induced autophagy and the release as extracellular vesicles via multivesicular bodies, BTV-induced apoptosis and the lytic release, as well as different pathways of release through budding via plasma membrane. The regulatory mechanisms of NS3 which is a key non-structural protein during the release of BTV are also discussed, providing a basis for further understanding the molecular mechanisms underpinning the infection, proliferation and release of BTV.

Natural DENV-2 NS2B/NS3 protease inhibitors from Myristica cinnamomea King

@#The NS2B/NS3 protease is crucial for the pathogenesis of the DENV. Therefore, the inhibition of this protease is considered to be the key strategy for the development of new antiviral drugs. In the present study, malabaricones C (3) and E (4), acylphenols from the fruits of Myristica cinnamomea King, have been respectively identified as moderate (27.33 ± 5.45 μM) and potent (7.55 ± 1.64 μM) DENV-2 NS2B/NS3 protease inhibitors, thus making this the first report on the DENV-2 NS2B/NS3 protease inhibitory activity of acylphenols. Based on the molecular docking studies, compounds 3 and 4 both have π-π interactions with Tyr161. While compound 3 has hydrogen bonding interactions with Gly151, Gly153 and Tyr161, compound 4 however, forms hydrogen bonds with Ser135, Asp129, Phe130 and Ile86 instead. The results from the present study suggests that malabaricones C (3) and E (4) could be employed as lead compounds for the development of new dengue antivirals from natural origin.

Development of an efficient in vivo cell-based assay system for monitoring hepatitis C virus genotype 4a NS3/4A protease activity

Background: Hepatitis C virus (HCV) represents a serious worldwide healthcare problem. No protective vaccines against HCV have been developed yet due to the fact that HCV is rapidly mutable, allowing the virus to escape from the neutralizing antibodies. Understanding of HCV was initially hampered by the inability to achieve viral replication in cell culture. Given its essential roles in viral polyprotein processing and immune evasion, HCV NS3/4A protease is a prime target for antiviral chemotherapy. We aimed to establish in vivo cell-based assay system for monitoring the activity of NS3/4A protease from HCV genotype 4a, the predominant genotype in Egypt, and the Middle East. Furthermore, the developed system was used to evaluate the inhibitory potency of a series of computer-designed chemically-synthesized compounds against NS3/4A protease from HCV genotype 4a. Materials and Methods: Native as well as mutant cleavage sites to NS3/4A protease were cloned in frame into ?-galactosidase gene of TA cloning vector. The target specificity of HCV NS3/4A was evaluated by coexpression of ?-galactosidase containing the protease cleavage site with NS3/4A protease construct in bacterial cells. The activity of ?-galactosidase was colorimetrically estimated in the cell lysate using orthonitro phenyl ?-D-galactopyanoside (ONPG) as a substrate. Results and Conclusions: We successfully developed an efficient cell-based system based on the blue/white selection of bacterial cells that are able to express functional/nonfunctional ?-galactosidase enzyme.

IgG1 and IgG4 antibodies against core and NS3 antigens of hepatitis C virus

Abstract INTRODUCTION: IgG subclasses involved in the immune response to hepatitis C virus (HCV) antigens have been rarely studied. We investigated the immune response mediated by IgG1 and IgG4 antibodies against the recombinant core and NS3 antigens in patients with chronic hepatitis C. METHODS: Sixty patients infected with HCV genotype 1 without antiviral treatment and 60 healthy subjects participated in the study. Serum levels of alanine aminotransferase, HCV viremia, and the presence of cryoglobulinemia and liver fibrosis were determined. We investigated the serum IgG1 and IgG4 antibodies against recombinant HCV core and NS3 non-structural protein antigens using amplified indirect ELISA. RESULTS: Anti-core and anti-NS3 IgG1 antibodies were detected in 33/60 (55%) and 46/60 (77%) patients, respectively, whereas only two healthy control samples reacted with an antigen (NS3). Anti-core IgG4 antibodies were not detected in either group, while 30/60 (50%) patients had anti-NS3 IgG4 antibodies. Even though there were higher levels of anti-NS3 IgG4 antibodies in patients with low viremia (< 8 × 105 IU/mL), IgG1 and IgG4 antibody levels did not correlate with ALT levels, the presence of cryoglobulinemia, or degree of hepatic fibrosis. High production of anti-core and anti-NS3 IgG1 antibodies was observed in chronic hepatitis C patients. In contrast, IgG4 antibodies seemed to only be produced against the NS3 non-structural antigen and appeared to be involved in viremia control. CONCLUSIONS: IgG1 antibodies against structural and non-structural antigens can be detected in chronic hepatitis C, while IgG4 antibodies seem to be selectively stimulated by non-structural HCV proteins, such as the NS3 antigen.

Zika virus NS3 can unwind dsDNA depending on ATP hydrolysis / 基础医学与临床

Objective To investigate whether Zika virus NS3 has ATP hydrolase and DNA helicase activity. Methods Zika NS3 with His tag was expressed in E.coli BL21 and purified by Nicke lagarose beads.ATP hy-drolysis assay was performed to examinethe ATPase activity of NS3.The dsDNA unwinding activity of NS3 was detected according to the principle of fluorescence resonance energy transfer(FRET).NS3 G198A mutant was generated by site-directed mutagenesis and its enzymatic activity was measured subsequently.Results Zika NS3 was capable of hydrolyzing ATP in vitro[Vmax=2.76 μmol/(L· min),Km=0.11 mmol/L].Moreover, Zika NS3 could unwind dsDNA in vitro as that proved by the fluorescence was enhancement in FRET system.G198A mutation impaired NS3 enzymatic activities, including ATP hydrolysis and dsDNA unwinding activities.Conclu-sions Zika NS3 has DNA helicase activity in vitro depending on ATP hydrolysis,and the glycine 198 is impor-tant for its enzymatic activity.

Advances in research on non-structural protein 3 of dengue virus / 中华微生物学和免疫学杂志

Dengue virus (DENV) is one of the most significant mosquito-borne viral pathogens that spread in the tropical and subtropical areas causing severe diseases in humans such as dengue fever (DF), dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). DENV RNA genome encodes three structural proteins and seven non-structural proteins. The non-structural protein 3 (NS3) contains two main functional domains: serine protease and RNA helicase. As a serine protease, NS3 together with host cell proteases can directly hydrolyze the ploy-protein that is translated from the viral genome into functional proteins. Functioning as a RNA helicase, it is closely related to the replication and transcriptional translation of the viral genome RNA. In this paper, the structure and functions of DENV NS3 and the research progress in related antiviral drugs were reviewed systematically.

In vitro inhibitory analysis of consensus siRNAs against NS3 gene of hepatitis C virus 1a genotype

OBJECTIVE@#To explore inhibitory effects of genome-specific, chemically synthesized siRNAs (small interference RNA) against NS3 gene of hepatitis C virus (HCV) 1a genotype in stable Huh-7 (human hepatoma) cells as well as against viral replication in serum-inoculated Huh-7 cells.@*METHODS@#Stable Huh-7 cells persistently expressing NS3 gene were produced under antibiotic gentamycin (G418) selection. The cell clones resistant to 1000 μg antibiotic concentration (G418) were picked as stable cell clones. The NS3 gene expression in stable cell clone was confirmed by RT-PCR and Western blotting. siRNA cell cytotoxicity was determined by MTT cell proliferation assay. Stable cell lines were transfected with sequence specific siRNAs and their inhibitory effects were determined by RT-PCR, real-time PCR and Western blotting. The viral replication inhibition by siRNAs in serum inoculated Huh-7 cells was determined by real-time PCR.@*RESULTS@#RT-PCR and Western blot analysis confirmed NS3 gene and protein expression in stable cell lines on day 10, 20 and 30 post transfection. MTT cell proliferation assay revealed that at most concentrated dose tested (50 nmol/L), siRNA had no cytotoxic effects on Huh-7 cells and cell proliferation remained unaffected. As demonstrated by the siRNA time-dependent inhibitory analysis, siRNA NS3-is44 showed maximum inhibition of NS3 gene in stable Huh-7 cell clones at 24 (80%, P = 0.013) and 48 h (75%, P = 0.002) post transfection. The impact of siRNAs on virus replication in serum inoculated Huh-7 cells also demonstrated significant decrease in viral copy number, where siRNA NS3-is44 exhibited 70% (P < 0.05) viral RNA reduction as compared to NS3-is33, which showed a 64% (P < 0.05) decrease in viral copy number. siRNA synergism (NS3-is33 + NS3-is44) decreased viral load by 84% (P < 0.05) as compared to individual inhibition by each siRNA (i.e., 64%-70% (P < 0.05)) in serum-inoculated cells. Synthetic siRNAs mixture (NS5B-is88 + NS3-is33) targeting different region of HCV genome (NS5B and NS3) also decreased HCV viral load by 85% (P < 0.05) as compared to siRNA inhibitory effects alone (70% and 64% respectively, P < 0.05).@*CONCLUSIONS@#siRNAs directed against NS3 gene significantly decreased mRNA and protein expression in stable cell clones. Viral replication was also vividly decreased in serum infected Huh-7 cells. Stable Huh-7 cells expressing NS3 gene is helpful to develop anti-hepatitis C drug screening assays. siRNA therapeutic potential along with other anti-HCV agents can be considered against hepatitis C.

3,5-Bis(arylidene)-4-piperidones as potential dengue protease inhibitors

Dengue is a severe mosquito-borne viral infection causing half a million deaths annually. Dengue virus NS2B/NS3 protease is a validated target for anti-dengue drug design. A series of hitherto unreported 3,5-bis(arylidene)-4-piperidones analogues-were synthesized and screenedagainst DENV2 NS2B/NS3 protease to elucidate their binding mechanism and orientation around the active sites. Results were validated through anDENV2 NS2B/NS3 protease assay using a fluorogenic Boc-Gly-Arg-Arg-AMC substrate. Nitro derivatives of 3,5-bis(arylidene)-4-piperidones (and) emerged as promising lead molecules for novel protease inhibitors with an ICof 15.22 and 16.23 µmol/L, respectively, compared to the standard, panduratin A, having ICof 57.28 µmol/L.

In vitro inhibitory analysis of consensus siRNAs against NS3 gene of hepatitis C virus 1a genotype

Objective To explore inhibitory effects of genome-specific, chemically synthesized siRNAs (small interference RNA) against NS3 gene of hepatitis C virus (HCV) 1a genotype in stable Huh-7 (human hepatoma) cells as well as against viral replication in serum-inoculated Huh-7 cells. Methods Stable Huh-7 cells persistently expressing NS3 gene were produced under antibiotic gentamycin (G418) selection. The cell clones resistant to 1 000 μg antibiotic concentration (G418) were picked as stable cell clones. The NS3 gene expression in stable cell clone was confirmed by RT-PCR and Western blotting. siRNA cell cytotoxicity was determined by MTT cell proliferation assay. Stable cell lines were transfected with sequence specific siRNAs and their inhibitory effects were determined by RT-PCR, real-time PCR and Western blotting. The viral replication inhibition by siRNAs in serum inoculated Huh-7 cells was determined by real-time PCR. Results RT-PCR and Western blot analysis confirmed NS3 gene and protein expression in stable cell lines on day 10, 20 and 30 post transfection. MTT cell proliferation assay revealed that at most concentrated dose tested (50 nmol/L), siRNA had no cytotoxic effects on Huh-7 cells and cell proliferation remained unaffected. As demonstrated by the siRNA time-dependent inhibitory analysis, siRNA NS3-is44 showed maximum inhibition of NS3 gene in stable Huh-7 cell clones at 24 (80%, P = 0.013) and 48 h (75%, P = 0.002) post transfection. The impact of siRNAs on virus replication in serum inoculated Huh-7 cells also demonstrated significant decrease in viral copy number, where siRNA NS3-is44 exhibited 70% (P < 0.05) viral RNA reduction as compared to NS3-is33, which showed a 64% (P < 0.05) decrease in viral copy number. siRNA synergism (NS3-is33 + NS3-is44) decreased viral load by 84% (P < 0.05) as compared to individual inhibition by each siRNA (i.e., 64%–70% (P < 0.05)) in serum-inoculated cells. Synthetic siRNAs mixture (NS5B-is88 + NS3-is33) targeting different region of HCV genome (NS5B and NS3) also decreased HCV viral load by 85% (P < 0.05) as compared to siRNA inhibitory effects alone (70% and 64% respectively, P < 0.05). Conclusions siRNAs directed against NS3 gene significantly decreased mRNA and protein expression in stable cell clones. Viral replication was also vividly decreased in serum infected Huh-7 cells. Stable Huh-7 cells expressing NS3 gene is helpful to develop anti-hepatitis C drug screening assays. siRNA therapeutic potential along with other anti-HCV agents can be considered against hepatitis C.

Virtual Screening for Potential Inhibitors of NS3 Protein of Zika Virus

Zika virus (ZIKV) is a mosquito borne pathogen, belongs to Flaviviridae family having a positive-sense single-stranded RNA genome, currently known for causing large epidemics in Brazil. Its infection can cause microcephaly, a serious birth defect during pregnancy. The recent outbreak of ZIKV in February 2016 in Brazil realized it as a major health risk, demands an enhanced surveillance and a need to develop novel drugs against ZIKV. Amodiaquine, prochlorperazine, quinacrine, and berberine are few promising drugs approved by Food and Drug Administration against dengue virus which also belong to Flaviviridae family. In this study, we performed molecular docking analysis of these drugs against nonstructural 3 (NS3) protein of ZIKV. The protease activity of NS3 is necessary for viral replication and its prohibition could be considered as a strategy for treatment of ZIKV infection. Amongst these four drugs, berberine has shown highest binding affinity of –5.8 kcal/mol and it is binding around the active site region of the receptor. Based on the properties of berberine, more similar compounds were retrieved from ZINC database and a structure-based virtual screening was carried out by AutoDock Vina in PyRx 0.8. Best 10 novel drug-like compounds were identified and amongst them ZINC53047591 (2-(benzylsulfanyl)-3-cyclohexyl-3H-spiro[benzo[h]quinazoline-5,1'-cyclopentan]-4(6H)-one) was found to interact with NS3 protein with binding energy of –7.1 kcal/mol and formed H-bonds with Ser135 and Asn152 amino acid residues. Observations made in this study may extend an assuring platform for developing anti-viral competitive inhibitors against ZIKV infection.

Direct anti-HCV agents

Unlike human immunodeficiency virus (HIV) and hepatitis B virus (HBV), hepatitis C virus (HCV) infection is a curable disease. Current direct antiviral agent (DAA) targets are focused on HCV NS3/4A protein (protease), NS5B protein (polymerase) and NS5A protein. The first generation of DAAs includes boceprevir and telaprevir, which are protease inhibitors and were approved for clinical use in 2011. The cure rate for genotype 1 patients increased from 45% to 70% when boceprevir or telaprevir was added to standard PEG-IFN/ribavirin. More effective and less toxic second generation DAAs supplanted these drugs by 2013. The second generation of DAAs includes sofosbuvir (Sovaldi), simeprevir (Olysio), and fixed combination medicines Harvoni and Viekira Pak. These drugs increase cure rates to over 90% without the need for interferon and effectively treat all HCV genotypes. With these drugs the "cure HCV" goal has become a reality. Concerns remain about drug resistance mutations and the high cost of these drugs. The investigation of new HCV drugs is progressing rapidly; fixed dose combination medicines in phase III clinical trials include Viekirax, asunaprevir+daclatasvir+beclabuvir, grazoprevir+elbasvir and others.

Molecular recognition mechanism and motion of HCV NS3/4A protease with Faldaprevir analogue / 生物工程学报

Faldaprevir analogue molecule (FAM) has been reported to effectively inhibit the catalytic activity of HCV NS3/4A protease, making it a potential lead compound against HCV. A series of HCV NS3/4A protease crystal structures were analyzed by bioinformatics methods, and the FAM-HCV NS3/4A protease crystal structure was chosen for this study. A 20.4 ns molecular dynamics simulation of the complex consists of HCV NS3/4A protease and FAM was conducted. The key amino acid residues for interaction and the binding driving force for the molecular recognition between the protease and FAM were identified from the hydrogen bonds and binding free energy analyses. With the driving force of hydrogen bonds and van der Waals, FAM specifically bind to the active pocket of HCV NS3/4A protease, including V130-S137, F152-D166, D77-D79 and V55, which agreed with the experimental data. The effect of R155K, D168E/V and V170T site-directed mutagenesis on FAM molecular recognition was analyzed for their effect on drug resistance, which provided the possible molecular explanation of FAM resistance. Finally, the system conformational change was explored by using free energy landscape and conformational cluster. The result showed four kinds of dominant conformation, which provides theoretical basis for subsequent design of Faldaprevir analogue inhibitors based on the structure of HCV NS3/4A protease.

Characterisation of divergent flavivirus NS3 and NS5 protein sequences detected in Rhipicephalus microplus ticks from Brazil

Transcripts similar to those that encode the nonstructural (NS) proteins NS3 and NS5 from flaviviruses were found in a salivary gland (SG) complementary DNA (cDNA) library from the cattle tick Rhipicephalus microplus. Tick extracts were cultured with cells to enable the isolation of viruses capable of replicating in cultured invertebrate and vertebrate cells. Deep sequencing of the viral RNA isolated from culture supernatants provided the complete coding sequences for the NS3 and NS5 proteins and their molecular characterisation confirmed similarity with the NS3 and NS5 sequences from other flaviviruses. Despite this similarity, phylogenetic analyses revealed that this potentially novel virus may be a highly divergent member of the genus Flavivirus. Interestingly, we detected the divergent NS3 and NS5 sequences in ticks collected from several dairy farms widely distributed throughout three regions of Brazil. This is the first report of flavivirus-like transcripts in R. microplus ticks. This novel virus is a potential arbovirus because it replicated in arthropod and mammalian cells; furthermore, it was detected in a cDNA library from tick SGs and therefore may be present in tick saliva. It is important to determine whether and by what means this potential virus is transmissible and to monitor the virus as a potential emerging tick-borne zoonotic pathogen.

Replication priority of hepatitis C virus genotype 2a in a Chinese cohort

HCV genotypes have been documented in clinical practice. The aim of this study was to determine the replication priority of different HCV genotypes in a Chinese HCV positive cohort. Serum samples from 491 apparently healthy Chinese blood donors testing positive for HCV antibodies and naive to antiviral drug therapy were tested. Genotyping analysis showed that genotypes 1b and 2a were predominant and accounted for 77.6% of the HCV infections. Among the genotype groups, individuals infected with genotype 2a had an HCV RNA viral load (10(8) copies/mL) about 200-fold (lg, 2.3) greater than those infected with other genotypes (10(4)-10(5) copies/mL) indicating a replication priority of genotype 2a. However, there was no correlation between HCV genotype and antibody response suggesting that the amplification advantage of genotype 2a results from a favorable interaction with the host cellular environment. In conclusion, HCV genotypes 1b and 2a are the predominant genotypes in China and genotype 2a possesses a significant replication priority compared with the other genotypes. This suggests the existence of host cellular factors that may act as drug-targets for entirely clearing HCV infection in the future.

Advances in antiviral therapy targeting to hepatitis C virus NS3/4A protease / 中华临床感染病杂志

Hepatitis C virus (HCV) genome is of high variation,which results in persistent infection of HCV and increases the incidence of liver cirrhosis and hepatocellular carcinoma.Following the successful paradigm established for HIV protease inhibitors,HCV NS3-4A serine protease has been selected as the main target for the development of small molecule antiviral agents.In this article,we review recent progress in the discovery and development of HCV NS3-4A protease inhibitors,and discuss their antiviral activities,pharmacokinetic properties,side effects and resistance profiles.

Variability and resistance mutations in the hepatitis C virus NS3 protease in patients not treated with protease inhibitors

The goal of treatment of chronic hepatitis C is to achieve a sustained virological response, which is defined as exhibiting undetectable hepatitis C virus (HCV) RNA levels in serum following therapy for at least six months. However, the current treatment is only effective in 50% of patients infected with HCV genotype 1, the most prevalent genotype in Brazil. Inhibitors of the serine protease non-structural protein 3 (NS3) have therefore been developed to improve the responses of HCV-infected patients. However, the emergence of drug-resistant variants has been the major obstacle to therapeutic success. The goal of this study was to evaluate the presence of resistance mutations and genetic polymorphisms in the NS3 genomic region of HCV from 37 patients infected with HCV genotype 1 had not been treated with protease inhibitors. Plasma viral RNA was used to amplify and sequence the HCV NS3 gene. The results indicate that the catalytic triad is conserved. A large number of substitutions were observed in codons 153, 40 and 91; the resistant variants T54A, T54S, V55A, R155K and A156T were also detected. This study shows that resistance mutations and genetic polymorphisms are present in the NS3 region of HCV in patients who have not been treated with protease inhibitors, data that are important in determining the efficiency of this new class of drugs in Brazil.

Progress on the second generation inhibitors of hepatitis C virus NS3/4A serine protease / 国际药学研究杂志

The progress of the second generation inhibitors of HCV NS3/4A serine protease, based on the modifications to the first generation ones (telaprevir, boceprevir, BILN-2061), is reviewed. The second generation inhibitors can significantly improve potency, pharmacokinetic profiles, and to some degree reduce the resistance induced by the first generation ones. The structure-activity relationships of these inhibitors are also discussed.