RESUMEN
Viral hemorrhagic fevers caused by members of the order Bunyavirales comprise endemic and emerging human infections that are significant public health concerns. Despite the disease severity, there are few therapeutic options available, and therefore effective antiviral drugs are urgently needed to reduce disease burdens. Bunyaviruses, like influenza viruses (IFVs), possess a cap-dependent endonuclease (CEN) that mediates the critical cap-snatching step of viral RNA transcription. We screened compounds from our CEN inhibitor (CENi) library and identified specific structural compounds that are 100 to 1,000 times more active in vitro than ribavirin against bunyaviruses, including Lassa virus, lymphocytic choriomeningitis virus (LCMV), and Junin virus. To investigate their inhibitory mechanism of action, drug-resistant viruses were selected in culture. Whole-genome sequencing revealed that amino acid substitutions in the CEN region of drug-resistant viruses were located in similar positions as those of the CEN α3-helix loop of IFVs derived under drug selection. Thus, our studies suggest that CENi compounds inhibit both bunyavirus and IFV replication in a mechanistically similar manner. Structural analysis revealed that the side chain of the carboxyl group at the seventh position of the main structure of the compound was essential for the high antiviral activity against bunyaviruses. In LCMV-infected mice, the compounds significantly decreased blood viral load, suppressed symptoms such as thrombocytopenia and hepatic dysfunction, and improved survival rates. These data suggest a potential broad-spectrum clinical utility of CENis for the treatment of both severe influenza and hemorrhagic diseases caused by bunyaviruses.
Asunto(s)
Antivirales , Endonucleasas , Orthobunyavirus , Animales , Antivirales/farmacología , Evaluación Preclínica de Medicamentos , Farmacorresistencia Viral/efectos de los fármacos , Farmacorresistencia Viral/genética , Endonucleasas/antagonistas & inhibidores , Humanos , Ratones , Orthobunyavirus/efectos de los fármacos , Orthobunyavirus/genética , Orthobunyavirus/metabolismo , Replicación Viral/efectos de los fármacosRESUMEN
Cytomegalovirus (CMV) is a major infectious agent causing severe complications in allogeneic hematopoietic cell transplantation (HCT) recipients, thereby warranting the need for aggressive preemptive or targeted antiviral therapy. However, prolonged or repeated use of antiviral agents, such as ganciclovir (GCV), foscarnet (FOS), and cidofovir (CDV), can result in drug-resistant CMV infection, posing challenges to successful outcomes. Here, we report a case of a patient with acute myeloid leukemia and drug-resistant CMV infection who presented with persistent CMV DNAemia, colitis, pneumonia, and encephalitis. An intra-host diversity of UL97 and UL54 mutations were detected through the genotypic resistance testing conducted on two blood samples (D+199 and D+224) and a cerebrospinal fluid (CSF) specimen (D+260) collected from the patient. UL97 L595W/L595F and L595W mutations were detected in the blood and CSF samples, respectively, that conferred GCV resistance. UL54 F412L mutation detected in all three samples conferred GCV/CDV resistance. However, the V787L mutation of UL54, conferring GCV/FOS resistance, was observed only in the D+224 blood sample. Despite combination therapy with FOS and high dose GCV and adjunctive therapy with leflunomide, the patient died from CMV infection and multiple organ failure on D+279. Further data on resistant mutations and intra-host diversity of CMV should be accumulated to elucidate the antiviral resistance and related outcomes.
Asunto(s)
Infecciones por Citomegalovirus , Trasplante de Células Madre Hematopoyéticas , Antivirales/farmacología , Antivirales/uso terapéutico , Cidofovir/uso terapéutico , Citomegalovirus/genética , Infecciones por Citomegalovirus/tratamiento farmacológico , Farmacorresistencia Viral/genética , Foscarnet/uso terapéutico , Ganciclovir/farmacología , Ganciclovir/uso terapéutico , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Humanos , Mutación , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Fosfotransferasas (Aceptor de Grupo Alcohol)/uso terapéuticoRESUMEN
Acyclovir (ACV) is currently included in the syndromic management algorithm for genital ulcer disease in South Africa, and is the recommended first-line treatment for herpes simplex virus 2 (HSV-2). In the majority of cases, HSV-2 resistance to ACV is due to amino acid changes within the viral thymidine kinase (TK). Phenotypic and genotypic ACV resistance surveillance of HSV-2 derived from genital ulcer disease swab specimens was conducted at a primary healthcare facility in Johannesburg between 2018 and 2020. The objectives of this surveillance were to identify ACV resistance-associated mutations and polymorphisms in HSV-2 TK, and to determine the phenotypic ACV resistance profiles of the corresponding clinical HSV-2 isolates. Genotypic analysis of TK from 67 HSV-2 positive genital ulcer swabs revealed 48 specimens with TK mutations, conferring 113 nucleotide changes. No resistance-associated mutations were found, however, we identified nine known natural polymorphisms (R26H, A27T, S29A, G39E, N78D, L140F, T159I, R220K and R284S) and five amino acid changes of unknown significance (R18C, G39K, M70R, P75S and L263P). Phenotypic susceptibility testing of 52 cultivable HSV-2 isolates revealed all to be susceptible to ACV with IC50 values of <2 µg/ml. The five amino acid changes of unknown significance identified by genotypic testing were not correlated to phenotypic ACV resistance, and therefore grouped as natural polymorphisms. We did not detect any unknown or resistance-associated mutations in specimens that could not be phenotypically tested for ACV resistance. Our findings will supplement existing databases of HSV antiviral resistance-associated mutations and polymorphisms that could be used for genotypic ACV resistance screening.
Asunto(s)
Herpes Genital , Herpes Simple , Herpesvirus Humano 1 , Aciclovir/farmacología , Aciclovir/uso terapéutico , Aminoácidos , Antivirales/farmacología , Antivirales/uso terapéutico , Farmacorresistencia Viral/genética , Femenino , Genitales/metabolismo , Herpes Genital/tratamiento farmacológico , Herpes Simple/tratamiento farmacológico , Herpesvirus Humano 1/genética , Herpesvirus Humano 2 , Humanos , Masculino , Sudáfrica , Timidina Quinasa/genética , Úlcera/tratamiento farmacológicoRESUMEN
Since its discovery in 1989, the road to a cure for hepatitis C virus (HCV) has been slow, but most patients can now expect to achieve a sustained virological response (SVR). With direct-acting antiviral (DAA) combination therapies such as glecaprevir/pibrentasvir and velpatasvir/sofosbuvir, 98% of patients successfully eradicate the virus, even if previous treatments failed or if resistance-associated substitutions (RASs) are present. Adverse events are rare or mild, and patients with compensated cirrhosis and other co-morbidities are often eligible for treatment. However, a small number of patients fail to eradicate the virus even after retreatment. The cause of failure is mainly due to emergence of NS5A P32 deletion mutants after initial DAA therapy in genotype 1b patients, although the reason is unknown for some patients. Alternative therapies that do not rely on NS5A inhibitors, such as sofosbuvir plus ribavirin, can be attempted in these patients. While scaled-up treatment efforts present a challenge, another problem is that many carriers are unaware of their infection. Long-term damage to the liver becomes irreversible, and patients who are not diagnosed in time can develop liver cancer or liver failure even after eliminating the virus. The long-term costs of treatment of advanced liver disease in undiagnosed patients relative to the immediate costs of DAA therapy should be considered. As no vaccine is yet available, eventual elimination of the virus requires identifying and treating undiagnosed cases and screening of high-risk populations such as injection drug users and men who have sex with men and female sex workers.
Asunto(s)
Hepatitis C Crónica , Hepatitis C , Trabajadores Sexuales , Minorías Sexuales y de Género , Antivirales , Farmacorresistencia Viral/genética , Quimioterapia Combinada , Femenino , Genotipo , Hepacivirus/genética , Hepatitis C/tratamiento farmacológico , Homosexualidad Masculina , Humanos , Masculino , Sofosbuvir/uso terapéuticoRESUMEN
Covid-19 pandemic has caused hundreds of thousands deaths and millions of infections and continued spreading violently. Although researchers are racing to find or develop effective drugs or vaccines, no drugs from modern medical system have been proven effective and the high mutant rates of the virus may lead it resistant to whatever drugs or vaccines developed following modern drug development procedure. Current evidence has demonstrated impressive healing effects of several Chinese medicines (CMs) for Covid-19, which urges us to reflect on the role of CM in the era of modern medicine. Undoubtedly, CM could be promising resources for developing drug candidates for the treatment of Covid-19 in a way similar to the development of artemisinin. But the theory that builds CM, like the emphasis of driving away exogenous pathogen (virus, etc.) by restoring self-healing capacity rather than killing the pathogen directly from the inside and the 'black-box' mode of diagnosing and treating patients, is as important, yet often ignored, an treasure as CM herbs and should be incorporated into modern medicine for future advancement and innovation of medical science.
Asunto(s)
COVID-19/terapia , Medicamentos Herbarios Chinos/uso terapéutico , Medicina Tradicional China , Antivirales/farmacología , Antivirales/uso terapéutico , COVID-19/epidemiología , Brotes de Enfermedades , Desarrollo de Medicamentos/métodos , Desarrollo de Medicamentos/normas , Farmacorresistencia Viral/genética , Quimioterapia Combinada , Medicamentos Herbarios Chinos/administración & dosificación , Medicamentos Herbarios Chinos/farmacología , Humanos , Medicina Tradicional China/métodos , Medicina Tradicional China/tendencias , Tasa de Mutación , Pandemias , Fitoterapia/métodos , SARS-CoV-2/efectos de los fármacos , SARS-CoV-2/fisiologíaRESUMEN
Covid-19 pandemic has caused hundreds of thousands deaths and millions of infections and continued spreading violently. Although researchers are racing to find or develop effective drugs or vaccines, no drugs from modern medical system have been proven effective and the high mutant rates of the virus may lead it resistant to whatever drugs or vaccines developed following modern drug development procedure. Current evidence has demonstrated impressive healing effects of several Chinese medicines (CMs) for Covid-19, which urges us to reflect on the role of CM in the era of modern medicine. Undoubtedly, CM could be promising resources for developing drug candidates for the treatment of Covid-19 in a way similar to the development of artemisinin. But the theory that builds CM, like the emphasis of driving away exogenous pathogen (virus, etc.) by restoring self-healing capacity rather than killing the pathogen directly from the inside and the 'black-box' mode of diagnosing and treating patients, is as important, yet often ignored, an treasure as CM herbs and should be incorporated into modern medicine for future advancement and innovation of medical science.
Asunto(s)
Humanos , Antivirales/uso terapéutico , COVID-19/terapia , Brotes de Enfermedades , Desarrollo de Medicamentos/normas , Farmacorresistencia Viral/genética , Quimioterapia Combinada , Medicamentos Herbarios Chinos/uso terapéutico , Medicina Tradicional China/tendencias , Tasa de Mutación , Pandemias , Fitoterapia/métodos , SARS-CoV-2/fisiologíaRESUMEN
The increasing prevalence of drug-resistant influenza viruses emphasizes the need for new antiviral countermeasures. The M2 protein of influenza A is a proton-gated, proton-selective ion channel, which is essential for influenza replication and an established antiviral target. However, all currently circulating influenza A virus strains are now resistant to licensed M2-targeting adamantane drugs, primarily due to the widespread prevalence of an M2 variant encoding a serine to asparagine 31 mutation (S31N). To identify new chemical leads that may target M2(S31N), we performed a virtual screen of molecules from two natural product libraries and identified chebulagic acid as a candidate M2(S31N) inhibitor and influenza antiviral. Chebulagic acid selectively restores growth of M2(S31N)-expressing yeast. Molecular modeling also suggests that chebulagic acid hydrolysis fragments preferentially interact with the highly-conserved histidine residue within the pore of M2(S31N) but not adamantane-sensitive M2(S31). In contrast, chebulagic acid inhibits in vitro influenza A replication regardless of M2 sequence, suggesting that it also acts on other influenza targets. Taken together, results implicate chebulagic acid and/or its hydrolysis fragments as new chemical leads for M2(S31N) and influenza-directed antiviral development.
Asunto(s)
Antivirales/farmacología , Benzopiranos/farmacología , Evaluación Preclínica de Medicamentos/métodos , Glucósidos/farmacología , Virus de la Influenza A/efectos de los fármacos , Proteínas de la Matriz Viral/antagonistas & inhibidores , Amantadina/química , Amantadina/farmacología , Animales , Antivirales/química , Perros , Farmacorresistencia Viral/efectos de los fármacos , Farmacorresistencia Viral/genética , Histidina/química , Virus de la Influenza A/fisiología , Células de Riñón Canino Madin Darby , Modelos Moleculares , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Mutación , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/genética , Proteínas de la Matriz Viral/química , Proteínas de la Matriz Viral/genética , Replicación Viral/efectos de los fármacosRESUMEN
INTRODUCTION: When protease inhibitor (PI)-based second-line ART fails, guidelines recommend drug resistance testing and individualized third-line treatment. However, PI-resistant viral strains are rare and drug resistance testing is costly. We investigated whether less costly PI-exposure testing can be used to select those patients who would benefit most from drug resistance testing. METHODS: We performed a retrospective analysis of South African adults living with HIV experiencing failure of ritonavir-boosted-lopinavir (LPV/r)-based second-line ART for whom drug resistance testing results were available. We included patients who received plasma-based drug resistance testing at a central South African reference laboratory in 2017 and patients who received dried blood spots (DBS)-based drug resistance testing at a rural South African clinic between 2009 and 2017. PI-exposure testing was performed on remnant plasma or DBS using liquid chromatography mass spectrometry (LCMS). Additionally, a low-cost immunoassay was used on plasma. Population genotypic drug resistance testing of the pol region was performed on plasma and DBS using standard clinical protocols. RESULTS: Samples from 544 patients (494 plasma samples and 50 DBS) were included. Median age was 41.0 years (IQR: 33.3 to 48.5) and 58.6% were women. Median HIV-RNA load was 4.9 log10 copies/mL (4.3 to 5.4). Prevalence of resistance to the NRTI-backbone was 70.6% (349/494) in plasma samples and 56.0% (28/50) in DBS. Major PI-resistance mutations conferring high-level resistance to LPV/r were observed in 26.7% (132/494) of plasma samples and 12% (6/50) of DBS. PI-exposure testing revealed undetectable LPV levels in 47.0% (232/494) of plasma samples and in 60.0% (30/50) of DBS. In pooled analysis of plasma and DBS samples, detectable LPV levels had a sensitivity of 90% (84% to 94%) and a negative predictive failure of 95% (91% to 97%) for the presence of major LPV/r resistance. CONCLUSIONS: PI-exposure testing revealed non-adherence in half of patients experiencing failure on second-line ART and accurately predicted the presence or absence of clinically relevant PI resistance. PI-exposure testing constitutes a novel screening strategy in patients with virological failure of ART that can differentiate between different underlying causes of therapy failure and may allow for more effective use of limited resources available for drug resistance testing.
Asunto(s)
Infecciones por VIH/tratamiento farmacológico , Inhibidores de la Proteasa del VIH/uso terapéutico , Insuficiencia del Tratamiento , Adulto , Farmacorresistencia Viral/genética , Femenino , Humanos , Lopinavir/uso terapéutico , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Estudios Retrospectivos , Ritonavir/uso terapéutico , Carga Viral/efectos de los fármacosRESUMEN
This paper continues a recent study of the spike protein sequence of the COVID-19 virus (SARS-CoV-2). It is also in part an introductory review to relevant computational techniques for tackling viral threats, using COVID-19 as an example. Q-UEL tools for facilitating access to knowledge and bioinformatics tools were again used for efficiency, but the focus in this paper is even more on the virus. Subsequence KRSFIEDLLFNKV of the S2' spike glycoprotein proteolytic cleavage site continues to appear important. Here it is shown to be recognizable in the common cold coronaviruses, avian coronaviruses and possibly as traces in the nidoviruses of reptiles and fish. Its function or functions thus seem important to the coronaviruses. It might represent SARS-CoV-2 Achilles' heel, less likely to acquire resistance by mutation, as has happened in some early SARS vaccine studies discussed in the previous paper. Preliminary conformational analysis of the receptor (ACE2) binding site of the spike protein is carried out suggesting that while it is somewhat conserved, it appears to be more variable than KRSFIEDLLFNKV. However compounds like emodin that inhibit SARS entry, apparently by binding ACE2, might also have functions at several different human protein binding sites. The enzyme 11ß-hydroxysteroid dehydrogenase type 1 is again argued to be a convenient model pharmacophore perhaps representing an ensemble of targets, and it is noted that it occurs both in lung and alimentary tract. Perhaps it benefits the virus to block an inflammatory response by inhibiting the dehydrogenase, but a fairly complex web involves several possible targets.
Asunto(s)
Betacoronavirus , Infecciones por Coronavirus/tratamiento farmacológico , Infecciones por Coronavirus/prevención & control , Pandemias/prevención & control , Neumonía Viral/tratamiento farmacológico , Neumonía Viral/prevención & control , Glicoproteína de la Espiga del Coronavirus/química , Vacunas Virales/inmunología , Secuencia de Aminoácidos , Enzima Convertidora de Angiotensina 2 , Animales , Antivirales/farmacología , Betacoronavirus/química , Betacoronavirus/genética , Betacoronavirus/inmunología , Sitios de Unión , COVID-19 , Vacunas contra la COVID-19 , Biología Computacional , Coronavirus/química , Coronavirus/genética , Coronavirus/inmunología , Infecciones por Coronavirus/genética , Infecciones por Coronavirus/inmunología , Infecciones por Coronavirus/virología , Diseño de Fármacos , Farmacorresistencia Viral/genética , Interacciones Microbiota-Huesped/genética , Interacciones Microbiota-Huesped/inmunología , Humanos , Modelos Moleculares , Mutación , Peptidomiméticos/farmacología , Peptidil-Dipeptidasa A/química , Peptidil-Dipeptidasa A/genética , Peptidil-Dipeptidasa A/metabolismo , Neumonía Viral/virología , SARS-CoV-2 , Homología de Secuencia de Aminoácido , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/inmunología , Vacunas Sintéticas/genética , Vacunas Sintéticas/inmunología , Vacunas Virales/genéticaRESUMEN
Acquisition of resistance mutations by HIV-1 isolates causes treatment failure among infected patients receiving antiretroviral therapy (ART). This study determined patterns of drug-resistance mutations (DRMs) among HIV-1 isolates from patients receiving first-line ART in South-eastern Nigeria. Blood samples were collected from HIV-1 infected patients accessing antiretroviral treatment centers at General Hospital Awo-Omamma, Imo state, State Hospital Asaba, Delta state and St Joseph's Catholic Hospital Adazi, Anambra state and used for HIV-1 DNA sequencing and phylogenetic analysis. DRMs were scored using combination of Stanford algorithm and the 2015 International Antiviral Society-USA list while drug susceptibility was predicted using Stanford algorithm. Twenty eight of the HIV-1 isolates were sequenced and identified as subtypes G (35.7%), CRF02_AG (57.1%) and unclassifiable, UG (7.1%). Major PI resistance-associated mutations were identified at two sites including M46L (16.7% of subtype G/UG) and V82L (6.3% of CRF02_AG). Minor PI resistance-associated mutations identified among subtype G/UG are L10V/I (8.3%) and K20I (100%) while L10V/I (50%), K20I (100%), L33F (6.3%) and N88D (6.3%) were identified among CRF02_AG. Other polymorphisms found include; I13V/A, E35Q, M36I/L, N37D/S/E/H, R57K/G, L63T/P/S/Q, C67E/S, H69K/R, K70R, V82I and L89M in the range of 28.6% to 100% among the different subtypes. Interpretation based on Stanford algorithm showed that Darunavir/ritonavir is the only regimen whose potency was not compromised by the circulating mutations. Identification of major and minor PI resistance mutations in this study underscores the need for drug resistance testing prior to initiation of second line antiretroviral therapy in Nigeria.
Asunto(s)
Fármacos Anti-VIH/uso terapéutico , VIH-1/efectos de los fármacos , Adulto , Fármacos Anti-VIH/farmacología , Farmacorresistencia Viral/genética , Femenino , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/virología , Inhibidores de la Proteasa del VIH/uso terapéutico , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Nigeria , Filogenia , Reacción en Cadena de la Polimerasa , Polimorfismo Genético/genética , Alineación de Secuencia , Análisis de Secuencia de ADNRESUMEN
Etravirine (ETR) is a nonnucleoside reverse transcriptase inhibitor (NNRTI) used in treatment-experienced individuals. Genotypic resistance test-interpretation systems can predict ETR resistance; however, genotype-based algorithms are derived primarily from HIV-1 subtype B and may not accurately predict resistance in non-B subtypes. The frequency of ETR resistance among recombinant subtype C HIV-1 and the accuracy of genotypic interpretation systems were investigated. HIV-1LAI containing full-length RT from HIV-1 subtype C-positive individuals experiencing virologic failure (>10,000 copies/ml and >1 NNRTI resistance-associated mutation) were phenotyped for ETR susceptibility. Fold change (FC) was calculated against a composite 50% effective concentration (EC50) from treatment-naive individuals and three classifications were assigned: (i) <2.9-FC, susceptible; (ii) ≥2.9- to 10-FC, partially resistant; and (iii) >10-FC, fully resistant. The Stanford HIVdb-v8.4 was used for genotype predictions merging the susceptible/potential low-level and low-level/intermediate groups for 3 × 3 comparison. Fifty-four of a hundred samples had reduced ETR susceptibility (≥2.9-FC). The FC correlated with HIVdb-v8.4 (Spearman's rho = 0.62; P < 0.0001); however, 44% of samples were partially (1 resistance classification difference) and 4% completely discordant (2 resistance classification differences). Of the 34 samples with an FC of >10, 26 were HIVdb-v8.4 classified as low-intermediate resistant. Mutations L100I, Y181C, or M230L were present in 27/34 (79%) of samples with an FC of >10 but only in 2/46 (4%) of samples with an FC of <2.9. No other mutations were associated with ETR resistance. Viruses containing the mutation K65R were associated with reduced ETR susceptibility, but 65R reversions did not increase ETR susceptibility. Therefore, genotypic interpretation systems were found to misclassify ETR susceptibility in HIV-1 subtype C samples. Modifications to genotypic algorithms are needed to improve the prediction of ETR resistance for the HIV-1 subtype C.
Asunto(s)
Antirretrovirales/uso terapéutico , Farmacorresistencia Viral/genética , Infecciones por VIH/tratamiento farmacológico , VIH-1/efectos de los fármacos , VIH-1/genética , Nitrilos/uso terapéutico , Pirimidinas/uso terapéutico , Inhibidores de la Transcriptasa Inversa/uso terapéutico , Algoritmos , Genotipo , VIH-1/clasificación , Humanos , Pruebas de Sensibilidad Microbiana , Sudáfrica , Insuficiencia del TratamientoRESUMEN
Influenza affects approximately 1 billion individuals each year resulting in between 290,000 and 650,000 deaths. Young children and immunocompromised individuals are at a particularly high risk of severe illness attributable to influenza and these are also the groups of individuals in which reduced susceptibility to neuraminidase inhibitors is most frequently seen. High levels of resistance emerged with previous adamantane therapy for influenza A and despite no longer being used to treat influenza and therefore lack of selection pressure, high levels of adamantane resistance continue to persist in currently circulating influenza A strains. Resistance to neuraminidase inhibitors has remained at low levels to date and the majority of resistance is seen in influenza A H1N1 pdm09 infected immunocompromised individuals receiving oseltamivir but is also seen less frequently with influenza A H3N2 and B. Rarely, resistance is also seen in the immunocompetent. There is evidence to suggest that these resistant strains (particularly H1N1 pdm09) are able to maintain their replicative fitness and transmissibility, although there is no clear evidence that being infected with a resistant strain is associated with a worse clinical outcome. Should neuraminidase inhibitor resistance become more problematic in the future, there are a small number of alternative novel agents within the anti-influenza armoury with different mechanisms of action to neuraminidase inhibitors and therefore potentially effective against neuraminidase inhibitor resistant strains. Limited data from use of novel agents such as baloxavir marboxil and favipiravir, does however show that resistance variants can also emerge in the presence of these drugs.
Asunto(s)
Antivirales/uso terapéutico , Farmacorresistencia Viral , Virus de la Influenza A/efectos de los fármacos , Virus de la Influenza B/efectos de los fármacos , Gripe Humana/tratamiento farmacológico , Farmacorresistencia Viral/efectos de los fármacos , Farmacorresistencia Viral/genética , Inhibidores Enzimáticos/uso terapéutico , Humanos , Virus de la Influenza A/genética , Virus de la Influenza B/genética , Gripe Humana/virología , Pruebas de Sensibilidad Microbiana , Neuraminidasa/antagonistas & inhibidores , Neuraminidasa/genética , Proteínas Virales/antagonistas & inhibidores , Proteínas Virales/genéticaRESUMEN
Arboviruses are a diverse group of viruses that are among the major causes of emerging infectious diseases. Arboviruses from the genera flavivirus and alphavirus are the most important human arboviruses from a public health perspective. During recent decades, these viruses have been responsible for millions of infections and deaths around the world. Over the past few years, several investigations have been carried out to identify antiviral agents to treat these arbovirus infections. The use of synthetic antiviral compounds is often unsatisfactory since they may raise the risk of viral mutation; they are costly and possess either side effects or toxicity. One attractive strategy is the use of plants as promising sources of novel antiviral compounds that present significant inhibitory effects on these viruses. In this review, we describe advances in the exploitation of compounds and extracts from natural sources that target the vital proteins and enzymes involved in arbovirus replication.
Asunto(s)
Infecciones por Alphavirus/tratamiento farmacológico , Antivirales/farmacología , Infecciones por Flavivirus/tratamiento farmacológico , Fitoquímicos/farmacología , Extractos Vegetales/farmacología , Alphavirus/efectos de los fármacos , Alphavirus/genética , Alphavirus/patogenicidad , Infecciones por Alphavirus/transmisión , Infecciones por Alphavirus/virología , Animales , Antivirales/uso terapéutico , Reservorios de Enfermedades/virología , Vectores de Enfermedades , Farmacorresistencia Viral/efectos de los fármacos , Farmacorresistencia Viral/genética , Flavivirus/efectos de los fármacos , Flavivirus/genética , Flavivirus/patogenicidad , Infecciones por Flavivirus/transmisión , Infecciones por Flavivirus/virología , Humanos , Mutación , Fitoquímicos/uso terapéutico , Extractos Vegetales/uso terapéutico , Proteínas Virales/antagonistas & inhibidores , Proteínas Virales/metabolismo , Replicación Viral/efectos de los fármacosRESUMEN
Alphaviruses are arthropod-borne, positive-stranded RNA viruses capable of causing severe disease with high morbidity. Chikungunya virus (CHIKV) is an alphavirus that causes a febrile illness which can progress into chronic arthralgia. The current lack of vaccines and specific treatment for CHIKV infection underscores the need to develop new therapeutic interventions. To discover new antiviral agents, we performed a compound screen in cell culture-based infection models and identified two carbocyclic adenosine analogues, 6'-ß-fluoro-homoaristeromycin (FHA) and 6'-fluoro-homoneplanocin A (FHNA), that displayed potent activity against CHIKV and Semliki Forest virus (SFV) with 50% effective concentrations in the nanomolar range at nontoxic concentrations. The compounds, designed as inhibitors of the host enzyme S-adenosylhomocysteine (SAH) hydrolase, impeded postentry steps in CHIKV and SFV replication. Selection of FHNA-resistant mutants and reverse genetics studies demonstrated that the combination of mutations G230R and K299E in CHIKV nonstructural protein 1 (nsP1) conferred resistance to the compounds. Enzymatic assays with purified wild-type (wt) SFV nsP1 suggested that an oxidized (3'-keto) form, rather than FHNA itself, directly inhibited the MTase activity, while a mutant protein with the K231R and K299E substitutions was insensitive to the compound. Both wt nsP1 and the resistant mutant were equally sensitive to the inhibitory effect of SAH. Our combined data suggest that FHA and FHNA inhibit CHIKV and SFV replication by directly targeting the MTase activity of nsP1, rather than through an indirect effect on host SAH hydrolase. The high potency and selectivity of these novel alphavirus mRNA capping inhibitors warrant further preclinical investigation of these compounds.
Asunto(s)
Adenosina/análogos & derivados , Antivirales/farmacología , Virus Chikungunya/efectos de los fármacos , Virus Chikungunya/fisiología , Adenosina/farmacología , Animales , Virus Chikungunya/patogenicidad , Chlorocebus aethiops , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Farmacorresistencia Viral/efectos de los fármacos , Farmacorresistencia Viral/genética , Guanosina Monofosfato/metabolismo , Mutación , Radioisótopos de Fósforo , Virus de los Bosques Semliki/efectos de los fármacos , Células Vero , Proteínas no Estructurales Virales/antagonistas & inhibidores , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismo , Replicación Viral/efectos de los fármacosRESUMEN
Background: Little is known about the impact of baseline resistance-associated mutations (RAMs) on the outcomes of alternative therapeutic strategies such as dual regimens. We assessed the efficacy of boosted darunavir plus raltegravir (DRV + RAL) dual regimen as a simplification strategy in virologically suppressed patients with protease inhibitors RAMs.Methods: Retrospective, multicentre study on the evolution of 228 heavily pretreated patients who switched to boosted DRV + RAL according to genotypic sensitivity score (GSS). Patients were classified as full susceptible (GSS = 2; n = 177), or with reduced darunavir susceptibility (GSS < 2; n = 51).Results: Median (range) number of prior antiretroviral regimens was 9 (6-14), with a median (range) of 2 (1-3), 4 (3-6), and 5 (2-9) major mutations to non-nucleoside reverse transcriptase inhibitors, nucleoside reverse transcriptase inhibitors, and protease inhibitors, respectively. The median time of virological suppression before simplification was 49 months (IQR 39.8-63.5). Patients with reduced darunavir GSS showed a higher number of protease inhibitors-RAMs (9.3 vs 4.5, p < .01) and were suppressed for longer time (median, 61 months). At week 96, the rate of virological failure was low (two cases, 0.9%; 95% confidence interval, CI, 0.4-2.7%), and the efficacy, excluding non-virological reasons, was 96.8% (95%CI, 90.2-98.4%), without differences according to GSS or protease inhibitors-RAMs. Furthermore, significant improvements in CD4+ counts and CD4/CD8 ratio were observed (p < .01) in both groups.Conclusions: Treatment simplification to a dual regimen of boosted DRV + RAL after long-term virological suppression was not associated with a high risk of treatment failure, even in patients harbouring protease inhibitors-resistant HIV infection.
Asunto(s)
Darunavir/uso terapéutico , Farmacorresistencia Viral/genética , Infecciones por VIH/tratamiento farmacológico , Inhibidores de la Proteasa del VIH/uso terapéutico , VIH-1/genética , Adulto , Anciano , Relación CD4-CD8 , Cobicistat/uso terapéutico , Combinación de Medicamentos , Sustitución de Medicamentos , Quimioterapia Combinada , Femenino , Genotipo , Infecciones por VIH/inmunología , Inhibidores de Integrasa VIH/uso terapéutico , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Mutación , Raltegravir Potásico/uso terapéutico , Estudios Retrospectivos , Ritonavir/uso terapéutico , Respuesta Virológica Sostenida , Factores de Tiempo , Insuficiencia del Tratamiento , Adulto JovenRESUMEN
Susceptibility of influenza A viruses to baloxavir can be affected by changes at amino acid residue 38 in the polymerase acidic (PA) protein. Information on replicative fitness of PA-I38-substituted viruses remains sparse. We demonstrated that substitutions I38L/M/S/T not only had a differential effect on baloxavir susceptibility (9- to 116-fold) but also on in vitro replicative fitness. Although I38L conferred undiminished growth, other substitutions led to mild attenuation. In a ferret model, control viruses outcompeted those carrying I38M or I38T substitutions, although their advantage was limited. These findings offer insights into the attributes of baloxavir-resistant viruses needed for informed risk assessment.
Asunto(s)
Antivirales/uso terapéutico , Farmacorresistencia Viral/genética , Subtipo H1N1 del Virus de la Influenza A/genética , Subtipo H3N2 del Virus de la Influenza A/genética , Infecciones por Orthomyxoviridae/tratamiento farmacológico , Oxazinas/uso terapéutico , Piridinas/uso terapéutico , Tiepinas/uso terapéutico , Triazinas/uso terapéutico , Replicación Viral/genética , Sustitución de Aminoácidos , Animales , Dibenzotiepinas , Modelos Animales de Enfermedad , Perros , Hurones , Secuenciación de Nucleótidos de Alto Rendimiento , Células de Riñón Canino Madin Darby , Masculino , Pruebas de Sensibilidad Microbiana , Morfolinas , Infecciones por Orthomyxoviridae/virología , Piridonas , ARN Polimerasa Dependiente del ARN/genética , Estaciones del Año , Resultado del Tratamiento , Proteínas Virales/genéticaRESUMEN
Human enterovirus A71 (HEVA71) causes hand, foot, and mouth disease (HFMD) in young children and is considered a major neurotropic pathogen but lacks effective antivirals. To identify potential therapeutic agents against HFMD, we screened a 502-compound flavonoid library for compounds targeting the HEVA71 internal ribosome entry site (IRES) that facilitates translation of the HEVA71 genome and is vital for the production of HEVA71 viral particles. We validated hits using cell viability and viral plaque assays and found that prunin was the most potent inhibitor of HEVA71. Downstream assays affirmed that prunin disrupted viral protein and RNA synthesis and acted as a narrow-spectrum antiviral against enteroviruses A and B, but not enterovirus C, rhinovirus A, herpes simplex 1, or chikungunya virus. Continuous HEVA71 passaging with prunin yielded HEVA71-resistant mutants with five mutations that mapped to the viral IRES. Knockdown studies showed that the mutations allowed HEVA71 to overcome treatment-induced suppression by differentially regulating recruitment of the IRES trans-acting factors Sam68 and hnRNPK without affecting the hnRNPA1-IRES interaction required for IRES translation. Furthermore, prunin effectively reduced HEVA71-associated clinical symptoms and mortality in HEVA71-infected BALB/c mice and suppressed hepatitis C virus at higher concentrations, suggesting a similar mechanism of prunin-mediated IRES inhibition for both viruses. These studies establish prunin as a candidate for further development as a HEVA71 therapeutic agent.
Asunto(s)
Enterovirus Humano A/fisiología , Infecciones por Enterovirus/tratamiento farmacológico , Infecciones por Enterovirus/virología , Sitios Internos de Entrada al Ribosoma , Florizina/análogos & derivados , Animales , Antibacterianos/farmacología , Muerte Celular/efectos de los fármacos , Proteínas de Unión al ADN/metabolismo , Evaluación Preclínica de Medicamentos , Farmacorresistencia Viral/efectos de los fármacos , Farmacorresistencia Viral/genética , Flavonoides/farmacología , Genes Reporteros , Hepacivirus/efectos de los fármacos , Ribonucleoproteína Nuclear Heterogénea A1/metabolismo , Humanos , Sitios Internos de Entrada al Ribosoma/genética , Luciferasas/metabolismo , Ratones Endogámicos BALB C , Mutación/genética , Florizina/farmacología , Florizina/uso terapéutico , Reproducibilidad de los Resultados , Replicación Viral/efectos de los fármacosRESUMEN
BACKGROUND: Hepatitis B is a very harmful and epidemic disease caused by hepatitis B virus (HBV). Although an effective anti-HBV vaccine is available, chronic infection poses still a huge health burden in the whole world. The present anti-HBV drugs including nucleoside analogues and interferonalpha have their limitations without exception. There is no effective drug and therapeutic method that can really and truly cure hepatitis B so far. The variability of HBV genome results in that a significant number of patients develop drug resistance during the long-term use of anti-HBV drugs. Hence, it is urgently needed to discover novel targets and develop new drugs against hepatitis B. OBJECTIVE: The review aims to provide the theory support for designing of the anti-HBV innovative drugs by offering a summary of the current situation of antiviral potential targets. RESULTS AND CONCLUSION: Since HBV is obligate intracellular parasite, and as such it depends on host cellular components and functions to replicate itself. The targeting both virus and host might be a novel therapeutic option for hepatitis B. Accordingly, we analyse the advances in the study of the potential drug targets for anti-HBV infection, focusing on targeting virus genome, on targeting host cellular functions and on targeting virus-host proteins interactions, respectively. Meanwhile, the immune targets against chronic hepatitis B are also emphasized. In short, the review provides a summary of antiviral therapeutic strategies to target virus factors, host factors and immune factors for future designing of the innovative drug against HBV infection.
Asunto(s)
Antivirales/farmacología , Antivirales/uso terapéutico , Virus de la Hepatitis B/efectos de los fármacos , Hepatitis B Crónica/tratamiento farmacológico , Animales , Descubrimiento de Drogas/métodos , Farmacorresistencia Viral/efectos de los fármacos , Farmacorresistencia Viral/genética , Genoma Viral/efectos de los fármacos , Genoma Viral/genética , Virus de la Hepatitis B/genética , Hepatitis B Crónica/virología , Interacciones Microbiota-Huesped/efectos de los fármacos , Interacciones Microbiota-Huesped/genética , HumanosRESUMEN
Recent emergence of direct-acting antivirals (DAAs) targeting hepatitis C virus (HCV) proteins has considerably enhanced the success of antiviral therapy. However, the appearance of DAA-resistant-associated variants is a cause of treatment failure, and the high cost of DAAs renders the therapy not accessible in countries with inadequate medical infrastructures. Therefore, the search for new inhibitors with a lower cost of production should be pursued. In this context, the crude extract of Juncus maritimus Lam. was shown to exhibit high antiviral activity against HCV in cell culture. Bio-guided fractionation allowed the isolation and identification of the active compound, dehydrojuncusol. A time-of-addition assay showed that dehydrojuncusol significantly inhibited HCV infection when added after virus inoculation of HCV genotype 2a (50% effective concentration [EC50] = 1.35 µM). This antiviral activity was confirmed with an HCV subgenomic replicon, and no effect on HCV pseudoparticle entry was observed. Antiviral activity of dehydrojuncusol was also demonstrated in primary human hepatocytes. No in vitro toxicity was observed at active concentrations. Dehydrojuncusol is also efficient on HCV genotype 3a and can be used in combination with sofosbuvir. Interestingly, dehydrojuncusol was able to inhibit RNA replication of two frequent daclatasvir-resistant mutants (L31M or Y93H in NS5A). Finally, mutants resistant to dehydrojuncusol were obtained and showed that the HCV NS5A protein is the target of the molecule. In conclusion, dehydrojuncusol, a natural compound extracted from J. maritimus, inhibits infection of different HCV genotypes by targeting the NS5A protein and is active against resistant HCV variants frequently found in patients with treatment failure.IMPORTANCE Tens of millions of people are infected with hepatitis C virus (HCV) worldwide. Recently marketed direct-acting antivirals (DAAs) targeting HCV proteins have enhanced the efficacy of treatment. However, due to its high cost, this new therapy is not accessible to the vast majority of infected patients. Furthermore, treatment failures have also been reported due to the appearance of viral resistance. Here, we report on the identification of a new HCV inhibitor, dehydrojuncusol, that targets HCV NS5A and is able to inhibit RNA replication of replicons harboring resistance mutations to anti-NS5A DAAs used in current therapy. Dehydrojuncusol is a natural compound isolated from Juncus maritimus, a halophilic plant species that is very common in coastlines worldwide. This molecule might serve as a lead for the development of a new therapy that is more accessible to hepatitis C patients in the future.
Asunto(s)
Hepacivirus/efectos de los fármacos , Fenantrenos/farmacología , Replicación Viral/efectos de los fármacos , Antivirales/farmacología , Línea Celular , Farmacorresistencia Viral/genética , Genotipo , Células HEK293 , Hepacivirus/genética , Hepatitis C/genética , Hepatitis C/virología , Hepatitis C Crónica/virología , Hepatocitos/virología , Humanos , Fenantrenos/metabolismo , Fenetilaminas/farmacología , Extractos Vegetales/farmacología , Inhibidores de Proteasas/farmacología , Replicón/efectos de los fármacos , RizomaRESUMEN
BACKGROUND: HIV-2 is a neglected virus despite estimates of 1-2 million people being infected worldwide. The virus is naturally resistant to some antiretrovirals used to treat HIV-1 and therapeutic options are limited for patients with HIV-2. METHODS: In this retrospective observational study, we analysed all HIV-2-infected individuals treated with integrase strand transfer inhibitors (INSTIs) recorded in the Spanish HIV-2 cohort. Demographics, treatment modalities, laboratory values, quantitative HIV-2 RNA and CD4 counts as well as drug resistance were analysed. RESULTS: From a total of 354 HIV-2-infected patients recruited by the Spanish HIV-2 cohort as of December 2017, INSTIs had been given to 44, in 18 as first-line therapy and in 26 after failing other antiretroviral regimens. After a median follow-up of 13 months of INSTI-based therapy, undetectable viraemia for HIV-2 was achieved in 89% of treatment-naive and in 65.4% of treatment-experienced patients. In parallel, CD4 gains were 82 and 126 cells/mm3, respectively. Treatment failure occurred in 15 patients, 2 being treatment-naive and 13 treatment-experienced. INSTI resistance changes were recognized in 12 patients: N155H (5), Q148H/R (3), Y143C/G (3) and R263K (1). CONCLUSIONS: Combinations based on INSTIs are effective and safe treatment options for HIV-2-infected individuals. However, resistance mutations to INSTIs are selected frequently in failing patients, reducing the already limited treatment options.