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- Akaberi, Dario, et al.
(författare)
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Baseline dasabuvir resistance in Hepatitis C virus from the genotypes 1, 2 and 3 and modeling of the NS5B-dasabuvir complex by the in silico approach.
- 2018
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Ingår i: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Current combination treatments with direct-acting antiviral agents (DAAs) can cure more than 95% of hepatitis C virus (HCV) infections. However, resistance-associated substitutions (RASs) may emerge and can also be present in treatment-naïve patients. Methods, results and discussion: In this study, a semi-pan-genotypic population sequencing method was developed and used to assess all NS5B amino acid variants between residue positions 310 and 564. Our method successfully sequenced more than 90% of genotype (GT) 1a, 1b, 2b and 3a samples. By using the population sequencing method with a cut-off of 20%, we found the dasabuvir RASs A553V and C445F to be a baseline polymorphism of GT 2b (8 out of 8) and GT 3a (18 out of 18) sequences, respectively. In GT 1a and 1b treatment-naïve subjects (n=25), no high-fold resistance polymorphism/RASs were identified. We further predicted dasabuvir's binding pose with the NS5B polymerase using the in silico methods to elucidate the reasons associated with the resistance of clinically relevant RASs. Dasabuvir was docked at the palm-I site and was found to form hydrogen bonds with the residues S288, I447, Y448, N291 and D318. The RAS positions 316, 414, 448, 553 and 556 were found to constitute the dasabuvir binding pocket.
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| 2. |
- Bergfors, Assar, et al.
(författare)
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Analysis of hepatitis C NS5A resistance associated polymorphisms using ultra deep single molecule real time (SMRT) sequencing
- 2016
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Ingår i: Antiviral Research. - : Elsevier BV. - 0166-3542 .- 1872-9096. ; 126, s. 81-89
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Tidskriftsartikel (refereegranskat)abstract
- Development of Hepatitis C virus (HCV) resistance against direct-acting antivirals (DAAs), including NS5A inhibitors, is an obstacle to successful treatment of HCV when DAAs are used in sub-optimal combinations. Furthermore, it has been shown that baseline (pre-existing) resistance against DAAs is present in treatment naive-patients and this will potentially complicate future treatment strategies in different HCV genotypes (GTs). Thus the aim was to detect low levels of NS5A resistant associated variants (RAVs) in a limited sample set of treatment-naive patients of HCV GT1a and 3a, since such polymorphisms can display in vitro resistance as high as 60000 fold. Ultra-deep single molecule real time (SMRT) sequencing with the Pacific Biosciences (PacBio) RSII instrument was used to detect these RAVs. The SMRT sequencing was conducted on ten samples; three of them positive with Sanger sequencing (GT1a Q30H and Y93N, and GT3a Y93H), five GT1a samples, and two GT3a non-positive samples. The same methods were applied to the HCV GT1a H77-plasmid in a dilution series, in order to determine the error rates of replication, which in turn was used to determine the limit of detection (LOD), as defined by mean + 3SD, of minority variants down to 0.24%. We found important baseline NS5A RAVs at levels between 0.24 and 0.5%, which could potentially have clinical relevance. This new method with low level detection of baseline RAVs could be useful in predicting the most cost-efficient combination of DAA treatment, and reduce the treatment duration for an HCV infected individual.
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| 3. |
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| 4. |
- Kileng, Hege, et al.
(författare)
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Personalized treatment of hepatitis C genotype 1a in Norway and Sweden 2014-2016 : a study of treatment outcome in patients with or without resistance-based DAA-therapy
- 2018
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Ingår i: Scandinavian Journal of Gastroenterology. - : Taylor & Francis. - 0036-5521 .- 1502-7708. ; 53:10-11, s. 1347-1353
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Resistance-associated substitutions (RASs) may impair treatment response to direct-acting antivirals (DAA) in hepatitis C virus (HCV) treatment. We investigated the effects of baseline NS3-RASs (Q80K and R155K) and clinically relevant NS5A-RASs in patients with HCV genotype (GT) 1a infection on treatment outcome, with or without resistance-based DAA-treatment. This multi-center study was carried out between 2014 and 2016.PATIENTS/METHODS: Treatment in the intervention group (n = 92) was tailored to baseline resistance. Detection of NS3-RAS led to an NS5A-inhibitor-based regimen and detection of NS5A-RAS to a protease-inhibitor regimen. Patients without baseline RAS in the intervention group and all patients in the control group (n = 101) received recommended standard DAA-treatment.RESULTS: The sustained virologic response rates (SVR) in the intervention and control groups were 97.8% (90/92) and 93.1% (94/101), respectively (p = .174). A trend toward higher SVR-rate in cirrhotic patients (p = .058) was noticed in the intervention group compared to the control group with SVR-rates 97.5% (39/40) and 83.3% (35/42), respectively. All patients with baseline NS3 (Q80K/R155K) or NS5A-RASs in the intervention group achieved SVR with personalized resistance-based treatment. In the control group, five patients with Q80K or R155K at baseline were treated with simeprevir + sofosbuvir and treatment failed in two of them. Furthermore, one of three patients who failed ledipasvir + sofosbuvir treatment had NS5A-RASs at baseline.CONCLUSIONS: In line with the findings of the OPTIMIST-2 trial for Q80K and the EASL-guidelines 2016 for NS5A-RASs, baseline RASs appeared to have an impact on treatment outcome albeit a statistical significance was not observed in this low-prevalence population.
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| 5. |
- Nordenankar, Karin, et al.
(författare)
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Targeted deletion of Vglut2 expression in the embryonal telencephalon promotes an anxiolytic phenotype of the adult mouse
- 2015
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Ingår i: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 120:3
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Anxiety is a natural emotion experienced by all individuals. However, when anxiety becomes excessive, it contributes to the substantial group of anxiety disorders that affect one in three people and thus are among the most common psychiatric disorders. Anxiolysis, the reduction of anxiety, is mediated via several large groups of therapeutical compounds, but the relief is often only temporary, and increased knowledge of the neurobiology underlying anxiety is needed in order to improve future therapies.AIM: We previously demonstrated that mice lacking forebrain expression of the Vesicular glutamate transporter 2 (Vglut2) from adolescence showed a strong anxiolytic behaviour as adults. In the current study, we wished to analyse if removal of Vglut2 expression already from mid-gestation of the mouse embryo would give rise to similar anxiolysis in the adult mouse.METHODS: We produced transgenic mice lacking Vglut2 from mid-gestation and analysed their affective behaviour, including anxiety, when they had reached adulthood.RESULTS: The transgenic mice lacking Vglut2 expression from mid-gestation showed certain signs of anxiolytic behaviour, but this phenotype was not as prominent as when Vglut2 was removed during adolescence.CONCLUSION: Our results suggest that both embryonal and adolescent forebrain expression of Vglut2 normally contributes to balancing the level of anxiety. As the neurobiological basis for anxiety is similar across species, our results in mice may help improve the current understanding of the neurocircuitry of anxiety, and hence anxiolysis, also in humans.
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