| 1. |
- Abidine, Yara, et al.
(författare)
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Cellular Chondroitin Sulfate and the Mucin-like Domain of Viral Glycoprotein C Promote Diffusion of Herpes Simplex Virus 1 While Heparan Sulfate Restricts Mobility
- 2022
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Ingår i: Viruses. - : MDPI AG. - 1999-4915. ; 14:8
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Tidskriftsartikel (refereegranskat)abstract
- The diffusion of viruses at the cell membrane is essential to reach a suitable entry site and initiate subsequent internalization. Although many viruses take advantage of glycosaminoglycans (GAG) to bind to the cell surface, little is known about the dynamics of the virus-GAG interactions. Here, single-particle tracking of the initial interaction of individual herpes simplex virus 1 (HSV-1) virions reveals a heterogeneous diffusive behavior, regulated by cell-surface GAGs with two main diffusion types: confined and normal free. This study reports that different GAGs can have competing influences in mediating diffusion on the cells used here: chondroitin sulfate (CS) enhances free diffusion but hinders virus attachment to cell surfaces, while heparan sulfate (HS) promotes virus confinement and increases entry efficiency. In addition, the role that the viral mucin-like domains (MLD) of the HSV-1 glycoprotein C plays in facilitating the diffusion of the virus and accelerating virus penetration into cells is demonstrated. Together, our results shed new light on the mechanisms of GAG-regulated virus diffusion at the cell surface for optimal internalization. These findings may be extendable to other GAG-binding viruses.
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| 2. |
- Bergström, Petra, et al.
(författare)
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Herpes Simplex Virus 1 and 2 Infections during Differentiation of Human Cortical Neurons
- 2021
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Ingår i: Viruses-Basel. - : MDPI AG. - 1999-4915. ; 13:10
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Tidskriftsartikel (refereegranskat)abstract
- Herpes simplex virus 1 (HSV-1) and 2 (HSV-2) can infect the central nervous system (CNS) with dire consequences; in children and adults, HSV-1 may cause focal encephalitis, while HSV-2 causes meningitis. In neonates, both viruses can cause severe, disseminated CNS infections with high mortality rates. Here, we differentiated human induced pluripotent stem cells (iPSCs) towards cortical neurons for infection with clinical CNS strains of HSV-1 or HSV-2. Progenies from both viruses were produced at equal quantities in iPSCs, neuroprogenitors and cortical neurons. HSV-1 and HSV-2 decreased viability of neuroprogenitors by 36.0% and 57.6% (p < 0.0001), respectively, 48 h post-infection, while cortical neurons were resilient to infection by both viruses. However, in these functional neurons, both HSV-1 and HSV-2 decreased gene expression of two markers of synaptic activity, CAMK2B and ARC, and affected synaptic activity negatively in multielectrode array experiments. However, unaltered secretion levels of the neurodegeneration markers tau and NfL suggested intact axonal integrity. Viral replication of both viruses was found after six days, coinciding with 6-fold and 22-fold increase in gene expression of cellular RNA polymerase II by HSV-1 and HSV-2, respectively. Our results suggest a resilience of human cortical neurons relative to the replication of HSV-1 and HSV-2.
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| 3. |
- Guimond, S. E., et al.
(författare)
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Synthetic Heparan Sulfate Mimetic Pixatimod (PG545) Potently Inhibits SARS-CoV-2 by Disrupting the Spike-ACE2 Interaction
- 2022
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Ingår i: ACS Central Science. - : American Chemical Society (ACS). - 2374-7943 .- 2374-7951. ; 8:5, s. 527-545
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Tidskriftsartikel (refereegranskat)abstract
- Heparan sulfate (HS) is a cell surface polysaccharide recently identified as a coreceptor with the ACE2 protein for the S1 spike protein on SARS-CoV-2 virus, providing a tractable new therapeutic target. Clinically used heparins demonstrate an inhibitory activity but have an anticoagulant activity and are supply-limited, necessitating alternative solutions. Here, we show that synthetic HS mimetic pixatimod (PG545), a cancer drug candidate, binds and destabilizes the SARS-CoV-2 spike protein receptor binding domain and directly inhibits its binding to ACE2, consistent with molecular modeling identification of multiple molecular contacts and overlapping pixatimod and ACE2 binding sites. Assays with multiple clinical isolates of SARS-CoV-2 virus show that pixatimod potently inhibits the infection of monkey Vero E6 cells and physiologically relevant human bronchial epithelial cells at safe therapeutic concentrations. Pixatimod also retained broad potency against variants of concern (VOC) including B.1.1.7 (Alpha), B.1.351 (Beta), B.1.617.2 (Delta), and B.1.1.529 (Omicron). Furthermore, in a K18-hACE2 mouse model, pixatimod significantly reduced SARS-CoV-2 viral titers in the upper respiratory tract and virus-induced weight loss. This demonstration of potent anti-SARS-CoV-2 activity tolerant to emerging mutations establishes proof-of-concept for targeting the HS-Spike protein-ACE2 axis with synthetic HS mimetics and provides a strong rationale for clinical investigation of pixatimod as a potential multimodal therapeutic for COVID-19.
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| 4. |
- Kalenga, T. M., et al.
(författare)
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Modified ent-Abietane Diterpenoids from the Leaves of Suregada zanzibariensis
- 2022
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 85:9, s. 2135-2141
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Tidskriftsartikel (refereegranskat)abstract
- The leaf extract of Suregada zanzibariensis gave two new modified ent-abietane diterpenoids, zanzibariolides A (1) and B (2), and two known triterpenoids, simiarenol (3) and fi-amyrin (4). The structures of the isolated compounds were elucidated based on NMR and MS data analysis. Single-crystal X-ray diffraction was used to establish the absolute configurations of compounds 1 and 2. The crude leaf extract inhibited the infectivity of herpes simplex virus 2 (HSV-2, IC50 11.5 mu g/mL) and showed toxicity on African green monkey kidney (GMK AH1) cells at CC50 52 mu g/ mL. The isolated compounds 1-3 showed no anti-HSV-2 activity and exhibited insignificant toxicity against GMK AH1 cells at >= 100 mu M.
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| 5. |
- Mahambo, Emanuel T, et al.
(författare)
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Crotofolane Diterpenoids and Other Constituents Isolated from Croton kilwae.
- 2023
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 1520-6025 .- 0163-3864. ; 86:2, s. 380-389
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Tidskriftsartikel (refereegranskat)abstract
- Six new crotofolane diterpenoids (1-6) and 13 known compounds (7-19) were isolated from the MeOH-CH2Cl2 (1:1, v/v) extracts of the leaves and stem bark of Croton kilwae. The structures of the new compounds were elucidated by extensive analysis of spectroscopic and mass spectrometric data. The structure of crotokilwaepoxide A (1) was confirmed by single-crystal X-ray diffraction, allowing for the determination of its absolute configuration. The crude extracts and the isolated compounds were investigated for antiviral activity against respiratory syncytial virus (RSV) and human rhinovirus type-2 (HRV-2) in HEp-2 and HeLa cells, respectively, for antibacterial activity against the Gram-positive Bacillus subtilis and the Gram-negative Escherichia coli, and for antimalarial activity against the Plasmodium falciparum Dd2 strain. ent-3β,19-Dihydroxykaur-16-ene (7) and ayanin (16) displayed anti-RSV activities with IC50 values of 10.2 and 6.1 μM, respectively, while exhibiting only modest cytotoxic effects on HEp-2 cells that resulted in selectivity indices of 4.9 and 16.4. Compounds 2 and 5 exhibited modest anti-HRV-2 activity (IC50 of 44.6 μM for both compounds), while compound 16 inhibited HRV-2 with an IC50 value of 1.8 μM. Compounds 1-3 showed promising antiplasmodial activities (80-100% inhibition) at a 50 μM concentration.
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| 6. |
- Miah, Masum, et al.
(författare)
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Identification of epidermal growth factor receptor-tyrosine kinase inhibitor targeting the VP1 pocket of human rhinovirus
- 2024
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Ingår i: ANTIMICROBIAL AGENTS AND CHEMOTHERAPY. - 0066-4804 .- 1098-6596.
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Tidskriftsartikel (refereegranskat)abstract
- Screening a library of 1,200 preselected kinase inhibitors for anti-human rhinovirus 2 (HRV-2) activity in HeLa cells identified a class of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) as effective virus blockers. These were based on the 4-anilinoquinazoline-7-oxypiperidine scaffold, with the most potent representative AZ5385 inhibiting the virus with EC50 of 0.35 mu M. Several structurally related analogs confirmed activity in the low mu M range, while interestingly, other TKIs targeting EGFR lacked anti-HRV-2 activity. To further probe this lack of association between antiviral activity and EGFR inhibition, we stained infected cells with antibodies specific for activated EGFR (Y1068) and did not observe a dependency on EGFR-TK activity. Instead, consecutive passages of HRV-2 in HeLa cells in the presence of a compound and subsequent nucleotide sequence analysis of resistant viral variants identified the S181T and T210A alterations in the major capsid VP1 protein, with both residues located in the vicinity of a known hydrophobic pocket on the viral capsid. Further characterization of the antiviral effects of AZ5385 showed a modest virus-inactivating (virucidal) activity, while anti-HRV-2 activity was still evident when the inhibitor was added as late as 10 h post infection. The RNA copy/infectivity ratio of HRV-2 propagated in AZ5385 presence was substantially higher than that of control HRV indicating that the compound preferentially targeted HRV progeny virions during their maturation in infected cells. Besides HRV, the compound showed anti-respiratory syncytial virus activity, which warrants its further studies as a candidate compound against viral respiratory infections.
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| 7. |
- Mollel, Jackson T., et al.
(författare)
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Anti-respiratory syncytial virus and anti-herpes simplex virus activity of six Tanzanian medicinal plants with extended studies of Erythrina abyssinica stem bark
- 2022
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Ingår i: Journal of Ethnopharmacology. - : Elsevier BV. - 0378-8741. ; 292
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Tidskriftsartikel (refereegranskat)abstract
- Ethnopharmacological relevance: Except for few highly pathogenic viruses, no antiviral drug has been approved for treatment of viral infections in humans. Plant extracts, selected based on their ethno-medical use, represent an important source of compounds for the development of novel candidate antiviral drugs. This especially concerns plants with ethnomedical records on their use in treatment of viral infections. Aim of the study: To identify and document medicinal plants used by traditional health practitioners (THPs) for treatment of respiratory infections and muco-cutaneous lesions in order to study their antiviral activity including identification of active components and elucidation of mode of antiviral activity. Materials and methods: The ethno-medical survey was performed in the Kagera region of Tanzania. The THPs were asked for plants used for treatment of signs and symptoms of respiratory infections and watery muco-cutaneous blisters in oral and genital regions. The plants identified were successively extracted with n-hexane, ethyl acetate and water, and the extracts assayed for anti-respiratory syncytial virus (RSV), anti-herpes simplex virus 2 (HSV-2), and anti-human parainfluenza virus 2 (HPIV-2) activity in cultured cells. Antiviral components were separated by ethanol precipitation and CL-6B chromatography, and the mode of antiviral activity elucidated by the time-of-addition assay and selection for the virus variants resistant to antiviral plant extract. Results: THPs identified fifteen plants used for treatment of respiratory infections and muco-cutaneous blisters. The water extract, but not n-hexane or ethyl acetate extracts, of six of these plants including Erythrina abyssinica stem bark, inhibited infectivity of two glycosaminoglycan-binding viruses i.e., RSV and HSV-2 but not the sialic acid binding HPIV-2. An activity-guided separation revealed that antiviral component(s) of water extract of E. abyssinica could be precipitated with ethanol. This sample potently and selectively inhibited RSV and HSV-2 infectivity in cultured cells with IC50 values of 2.1 μg/ml (selectivity index >476) and 0.14 μg/ml (selectivity index >7143) respectively. The sample exhibited inhibitory effect on the virus attachment to and entry into the cells by directly targeting the viral particles. Indeed, 10 consecutive virus passages in HEp-2 cells in the presence of this extract selected for a resistant RSV variant lacking the attachment, viral membrane-associated, G protein due to a stop codon at amino acid residue 33 (Leu33stop). Fractionation of the E. abyssinica extract on a CL-6B column revealed that anti-RSV and HSV-2 activity correlated with carbohydrate content. The most pronounced antiviral activity was associated with a carbohydrate containing ingredient of molecular mass of <5 kDa, which may polymerize to antiviral composites of up to 410 kDa. Conclusions: Altogether, the water extract of six medicinal plants showed anti-RSV and anti-HSV-2 activities. Extended studies of the stem bark of E. abyssinica identified antiviral components that potently and selectively inhibited infectivity of free RSV and HSV-2 particles, a feature of importance in topical treatment of these infections. This observation confirms ethno-medical information concerning the use of E. abyssinica extract for treatment of respiratory infections and herpetic lesions. © 2022 The Authors
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| 8. |
- Olofsson, Sigvard, 1948, et al.
(författare)
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Structure and Role of O-Linked Glycans in Viral Envelope Proteins
- 2023
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Ingår i: Annual Review of Virology. - : Annual Reviews. - 2327-056X. ; 10:1, s. 283-304
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Tidskriftsartikel (refereegranskat)abstract
- N- and O-glycans are both important constituents of viral envelope glycoproteins. O-linked glycosylation can be initiated by any of 20 different human polypeptide O-acetylgalactosaminyl transferases, resulting in an important functional O-glycan heterogeneity. O-glycans are organized as solitary glycans or in clusters of multiple glycans forming mucin-like domains. They are functional both in the viral life cycle and in viral colonization of their host. Negatively charged O-glycans are crucial for the interactions between glycosaminoglycan-binding viruses and their host. A novel mechanism, based on controlled electrostatic repulsion, explains how such viruses solve the conflict between optimized viral attachment to target cells and efficient egress of progeny virus. Conserved solitary O-glycans appear important for viral uptake in target cells by contributing to viral envelope fusion. Dual roles of viral O-glycans in the host B cell immune response, either epitope blocking or epitope promoting, may be exploitable for vaccine development. Finally, specific virus-induced O-glycans may be involved in viremic spread.
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| 9. |
- Saguti, Fredy, et al.
(författare)
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Surveillance of wastewater revealed peaks of SARS-CoV-2 preceding those of hospitalized patients with COVID-19.
- 2021
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Ingår i: Water research. - : Elsevier BV. - 1879-2448 .- 0043-1354. ; 189
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Tidskriftsartikel (refereegranskat)abstract
- SARS-CoV-2 was discovered among humans in Wuhan, China in late 2019, and then spread rapidly, causing a global pandemic. The virus was found to be transmitted mainly by respiratory droplets from infected persons or by direct contact. It was also shown to be excreted in feces, why we investigated whether the virus could be detected in wastewater and if so, to which extent its levels reflects its spread in society. Samples of wastewater from the city of Gothenburg, and surrounding municipalities in Sweden were collected daily from mid-February until June 2020 at the Rya wastewater treatment plant. Flow proportional samples of wastewater were collected to ensure that comparable amounts were obtained for analysis. Daily samples were pooled into weekly samples. Virus was concentrated on a filter and analyzed by RT-qPCR. The amount of SARS-CoV-2 varied with peaks approximately every four week, preceding variations in number of newly hospitalized patients by 19-21 days. At that time virus testing for COVID-19 was limited to patients with severe symptoms. Local differences in viral spread was shown by analyzing weekly composite samples of wastewater from five sampling sites for four weeks. The highest amount of virus was found from the central, eastern, and northern parts of the city. SARS-CoV-2 was also found in the treated effluent wastewater from the WWTP discharged into the recipient, the Göta River, although with a reduction of 4-log10. The viral peaks with regular temporal intervals indicated that SARS-CoV-2 may have a cluster spread, probably reflecting that the majority of infected persons only spread the disease during a few days. Our results are important for both the planning of hospital care and to rapidly identify and intervene against local spread of the virus.
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| 10. |
- Saguti, Fredy, et al.
(författare)
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Surveillance of wastewater revealed peaks of SARS-CoV-2 preceding those of hospitalized patients with COVID-19
- 2021
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 189
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Tidskriftsartikel (refereegranskat)abstract
- SARS-CoV-2 was discovered among humans in Wuhan, China in late 2019, and then spread rapidly, causing a global pandemic. The virus was found to be transmitted mainly by respiratory droplets from infected persons or by direct contact. It was also shown to be excreted in feces, why we investigated whether the virus could be detected in wastewater and if so, to which extent its levels reflects its spread in society. Samples of wastewater from the city of Gothenburg, and surrounding municipalities in Sweden were collected daily from mid-February until June 2020 at the Rya wastewater treatment plant. Flow proportional samples of wastewater were collected to ensure that comparable amounts were obtained for analysis. Daily samples were pooled into weekly samples. Virus was concentrated on a filter and analyzed by RT-qPCR. The amount of SARS-CoV-2 varied with peaks approximately every four week, preceding variations in number of newly hospitalized patients by 19-21 days. At that time virus testing for COVID-19 was limited to patients with severe symptoms. Local differences in viral spread was shown by analyzing weekly composite samples of wastewater from five sampling sites for four weeks. The highest amount of virus was found from the central, eastern, and northern parts of the city. SARS-CoV-2 was also found in the treated effluent wastewater from the WWTP discharged into the recipient, the Göta River, although with a reduction of 4-log10. The viral peaks with regular temporal intervals indicated that SARS-CoV-2 may have a cluster spread, probably reflecting that the majority of infected persons only spread the disease during a few days. Our results are important for both the planning of hospital care and to rapidly identify and intervene against local spread of the virus.
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