| 1. |
- Barreca, Maria Letizia, et al.
(författare)
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Structure-Based Discovery of Pyrazolobenzothiazine Derivatives As Inhibitors of Hepatitis C Virus Replication
- 2013
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 56:6, s. 2270-2282
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Tidskriftsartikel (refereegranskat)abstract
- The NS5B RNA-dependent RNA polymerase is an attractive target for the development of novel and selective inhibitors of hepatitis C virus replication. To identify novel structural hits as anti-HCV agents, we performed structure based virtual screening of our in-house library followed by rational drug design, organic synthesis, and biological testing. These studies led to the identification of pyrazolobenzothiazine scaffold as a suitable template for obtaining novel anti-HCV agents targeting the NS5B polymerase. The best compound of this series was the meta-fluoro-N-1-phenyl pyrazolobenzothiazine derivative 4a, which exhibited an EC50 = 3.6 mu M, EC90 = 25.6 mu M, and CC50 > 180 mu M in the Huh 9-13 replicon system, thus providing a good starting point for further hit evolution.
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| 2. |
- Belfrage, Anna Karin, et al.
(författare)
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Discovery of pyrazinone based compounds that potently inhibit the drug resistant enzyme variant R155K of the hepatitis C virus NS3 protease
- 2016
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Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896 .- 1464-3391. ; 24:12, s. 2603-2620
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we present the design and synthesis of 2(1H)-pyrazinone based HCV NS3 protease inhibitors with variations in the C-terminus. Biochemical evaluation was performed using genotype 1a, both the wildtype and the drug resistant enzyme variant, R155K. Surprisingly, compounds without an acidic sulfonamide retained good inhibition, challenging our previous molecular docking model. Moreover, selected compounds in this series showed nanomolar potency against R155K NS3 protease; which generally confer resistance to all HCV NS3 protease inhibitors approved or in clinical trials. These results further strengthen the potential of this novel substance class, being very different to the approved drugs and clinical candidates, in the development of inhibitors less sensitive to drug resistance.
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| 3. |
- Hultén, Johan, et al.
(författare)
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Cyclic HIV-1 protease inhibitors derived from mannitol : synthesis, inhibitory potencies, and computational predictions of binding affinities
- 1997
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 40:6, s. 885-897
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Tidskriftsartikel (refereegranskat)abstract
- Ten C-2-symmetric cyclic urea and sulfamide derivatives have been synthesized from L-mannonic gamma-lactone and D-mannitol. The results of experimental measurement of their inhibitory potencies against HIV-1 protease were compared to calculated free energies of binding derived from molecular dynamics (MD) simulations. The compounds were selected, firstly, to enable elucidation of the role of stereochemistry for binding affinity (1a-d) and, secondly, to allow evaluation of the effects of variation in the link to the P1 and P1' phenyl groups on affinity (la and 2-5). Thirdly, compounds with hydrogen bond-accepting or -donating groups attached to the phenyl groups in the P2 and P2' side chains (6 and 7) were selected. Binding free energies were estimated by a linear response method, whose predictive power for estimating binding affinities from MD simulations was demonstrated.
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| 4. |
- Luttens, Andreas, et al.
(författare)
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Ultralarge Virtual Screening Identifies SARS-CoV-2 Main Protease Inhibitors with Broad-Spectrum Activity against Coronaviruses
- 2022
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 144:7, s. 2905-2920
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Tidskriftsartikel (refereegranskat)abstract
- Drugs targeting SARS-CoV-2 could have saved millions of lives during the COVID-19 pandemic, and it is now crucial to develop inhibitors of coronavirus replication in preparation for future outbreaks. We explored two virtual screening strategies to find inhibitors of the SARS-CoV-2 main protease in ultralarge chemical libraries. First, structure-based docking was used to screen a diverse library of 235 million virtual compounds against the active site. One hundred top-ranked compounds were tested in binding and enzymatic assays. Second, a fragment discovered by crystallographic screening was optimized guided by docking of millions of elaborated molecules and experimental testing of 93 compounds. Three inhibitors were identified in the first library screen, and five of the selected fragment elaborations showed inhibitory effects. Crystal structures of target-inhibitor complexes confirmed docking predictions and guided hit-to-lead optimization, resulting in a noncovalent main protease inhibitor with nanomolar affinity, a promising in vitro pharmacokinetic profile, and broad-spectrum antiviral effect in infected cells.
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| 5. |
- Manfroni, Giuseppe, et al.
(författare)
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The Versatile Nature of the 6-Aminoquinolone Scaffold : Identification of Submicromolar Hepatitis C Virus NS5B Inhibitors
- 2014
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 57:5, s. 1952-1963
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Tidskriftsartikel (refereegranskat)abstract
- We have previously reported that the 6-aminoquinolone chemotype is a privileged scaffold to obtain antibacterial and antiviral agents. Herein we describe the design, synthesis, and enzymatic and cellular characterization of new 6-aminoquinolone derivatives as potent inhibitors of NS5B polymerase, an attractive and viable therapeutic target to develop safe anti-HCV agents. The 6-amino-7-[4-(2-pyridinyl)-1-piperazinyl]quinolone derivative 8 proved to be the best compound of this series, exhibiting an IC50 value of 0.069 mu M against NS5B polymerase and selective antiviral effect (EC50 = 3.03 mu M) coupled with the absence of any cytostatic effect (CC50 > 163 mu M; SI > 54) in Huh 9-13 cells carrying a HCV genotype 1b, as measured by MTS assay. These results indicate that the 6-aminoquinolone scaffold is worthy of further investigation in the context of NS5B-targeted HCV drug discovery programs.
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| 6. |
- Ahlsén, Göran, et al.
(författare)
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Resistance profiles of cyclic and linear inhibitors of HIV-1 protease
- 2002
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Ingår i: Antiviral Chemistry & Chemotherapy. - 0956-3202 .- 2040-2066. ; 13:1, s. 27-37
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Tidskriftsartikel (refereegranskat)abstract
- Resistance to anti-HIV protease drugs is a major problem in the design of AIDS drugs with long-term efficacy. To identify structural features associated with a certain resistance profile, the inhibitory properties of a series of symmetric and asymmetric cyclic sulfamide, cyclic urea and linear transition-state analogue inhibitors of HIV-1 protease were investigated using wild-type and mutant enzyme. To allow a detailed structure-inhibition analysis, enzyme with single, double, triple and quadruple combinations of G48V, V82A, 184V and L90M substitutions was used. Kinetic analysis of the mutants revealed that catalytic efficiency was 1-30% of that for the wild-type enzyme, a consequence of reduced kcat in all cases and an increased KM for all mutants except for the G48V enzyme. The overall structure-inhibitory profiles of the cyclic compounds were similar, and the inhibition of the V82A, 184V and G48V/L90M mutants were less efficient than of the wild-type enzyme. The greatest increase in Ki was generally observed for the 184V mutant and least for the G48V/L90M mutant, and additional combinations of mutations did not result in improved inhibition profiles for the cyclic compounds. An extended analysis of additional mutants, and including a set of linear compounds, showed that the profile was unique for each compound, and did not reveal any general structural features associated with a certain inhibition profile. The effects of structural modifications in the inhibitors, or of mutations, were not additive and they differed depending on their context. The results demonstrate the difficulties in predicting resistance, even for closely related compounds, and designing compounds with improved resistance profiles.
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| 7. |
- Alexandersson, Erik, et al.
(författare)
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Transcriptional regulation of aquaporins in accessions of Arabidopsis in response to drought stress.
- 2010
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Ingår i: Plant Journal. - 1365-313X. ; 61, s. 650-660
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Tidskriftsartikel (refereegranskat)abstract
- Summary Aquaporins facilitate water transport over cellular membranes and are therefore believed to play an important role in water homeostasis. In higher plants aquaporin-like proteins, also called major intrinsic proteins (MIPs), are divided into 5 subfamilies. We have previously shown that MIP transcription in Arabidopsis thaliana generally is down-regulated in leaves upon drought stress, apart from two members of the Plasma membrane Intrinsic Protein (PIP) subfamily, AtPIP1;4 and AtPIP2;5, which are up-regulated. In order to assess if this regulation is general or accession-specific we monitored gene expression of all PIPs in five Arabidopsis accessions. Overall drought regulation of PIPs was well conserved for all five accessions tested suggesting a general and fundamental physiological role of this drought response. In addition, significant differences among accessions were identified for transcripts of three PIP genes. Principal component analysis showed that most of the PIP transcriptional variation during drought stress could be explained by one variable linked to leaf water content. Promoter-GUS constructs of AtPIP1;4, AtPIP2;5 and also AtPIP2;6, which is unresponsive to drought stress, had distinct expression patterns concentrated to the base of the leaf petioles and parts of the flowers. The presence of drought stress response elements within the 1.6 kb promoter regions of AtPIP1;4 and AtPIP2;5, was demonstrated by comparing transcription of the promoter reporter construct and the endogenous gene upon drought stress. Analysis by ATTED-II and other web-based bioinformatical tools showed that several of the MIPs down-regulated upon drought are strongly co-expressed, whereas AtPIP1;4, AtPIP2;5 and AtPIP2;6 are not co-expressed.
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| 8. |
- Alterman, Mathias, et al.
(författare)
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P1/P1' modified HIV protease inhibitors as tools in two new sensitive surface plasmon resonance biosensor screening assays
- 2001
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Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier. - 0928-0987 .- 1879-0720. ; 13:2, s. 203-212
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Tidskriftsartikel (refereegranskat)abstract
- The commonly used HIV-1 protease assays rely on measurements of the effect of inhibitions on the hydrolysis rate of synthetic peptides. Recently an assay based on surface plasmon resonance (SPR) was introduced. We have taken advantage of the fact that the SPR signal is proportional to the mass of the analyte interacting with the immobilised molecule and developed two new improved efficient competition assay methods. Thus, high molecular weight binders were used as amplifiers of the surface plasmon resonance signal. Linkers were attached by a Heck reaction to the para-positions of the P1/P1′ benzyloxy groups of a linear C2-symmetric C-terminal duplicated inhibitor to enable (a) biotin labelling or (b) direct immobilisation of the inhibitor to the biosensor surface matrix. The interaction properties of a series of 17 structurally diverse inhibitors was assessed and compared to previously reported data. The most sensitive assay was obtained by immobilising the enzyme and amplifying the signal with an antibody, giving a detection range between 0.1 nM and 10 μM. Immobilisation of the inhibitor resulted in a stable and durable surface but a narrower detection range (1–100 nM). The two competition assays are anticipated to be very suitable for fast screening of potential HIV inhibitors.
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| 9. |
- Angsten, Gertrud, et al.
(författare)
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Outcome of laparoscopic versus open gastrostomy in children
- 2015
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Ingår i: Pediatric surgery international (Print). - : Springer Science and Business Media LLC. - 0179-0358 .- 1437-9813. ; 31:11, s. 1067-1072
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Tidskriftsartikel (refereegranskat)abstract
- Laparoscopic gastrostomy (LAPG) has gained popularity in children. The aim of this study was to compare the outcome of LAPG versus open gastrostomy (OG) in children with focus on complications, operative times and postoperative length of stay. Retrospective study of children who had gastrostomies inserted at our tertiary Pediatric Surgery Center from 2000 until 2013. The indications for a gastrostomy were an anticipated need for enteral support for at least 6 months. Totally 243 children were included in the study, 83 with LAPG and 160 with OG. We found a significant difference in postoperative length of stay, 3 days in the LAPG group versus 4 days in the OG group but no difference in a sub-group analysis from 2010 to 2013 when both techniques were used. There was no difference in median operative time or complications rates. Granuloma was the dominating complication in both groups. These two feeding-access techniques are comparable regarding complications, operative times and postoperative length of stay. The choice of surgical method should be individualized based on the patient's characteristics and the experience of the surgeon. The favorable results with LAPG in adults are not necessarily transferable to children since there are physiological and anatomical differences.
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| 10. |
- Bagge, Johan, et al.
(författare)
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In situ hybridization studies favouring the occurrence of a local production of BDNF in the human Achilles tendon
- 2012
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Ingår i: Histology and Histopathology. - 0213-3911 .- 1699-5848. ; 27:9, s. 1239-1246
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Tidskriftsartikel (refereegranskat)abstract
- Brain derived neurotrophic factor (BDNF) is a multipotent neurotrophin known for its growth-influencing and apoptosis-modulating functions, as well as for its function to interact with neurotransmitters/neuromodulators. BDNF is reported to be mainly produced in the brain. BDNF can be absorbed into peripheral tissue from the blood stream. Expression of this neurotrophin at the protein level, as well as of the neurotrophin receptor p75, has been previously shown for the principal cells (tenocytes) of the Achilles tendon. However, there is no proof at the mRNA level that BDNF is produced by the tenocytes. As the Achilles tendon tenocytes show "neuronal-like" characteristics, in the form of expressions favouring synthesis of several neuromodulators/neurotransmitters, and as BDNF especially is produced in neurons, it is of interest to confirm this. In the present study, therefore, in situ hybridization for demonstration of BDNF mRNA was performed on biopsies from Achilles tendons of patients with tendinosis and pain-free non-tendinosis individuals. The results showed that the tenocytes of both groups exhibited BDNF mRNA reactions. These observations indeed favour the idea that BDNF is produced by tenocytes in the human Achilles tendon, why Achilles tendon tissue is a tissue in which BDNF can be locally produced. BDNF can have modulatory functions for the tenocytes, including apoptosis-modifying effects via actions on the p75 receptor and interactive effects with neurotransmitters/neuromodulators produced in these cells. This possibility should be further studied for Achilles tendon tissue.
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