The amino acid substitution of aspartic acid to glycine in hemagglutinin (HA) in position 222 (HA-D222G) as well as HA-222D/G polymorphism of pandemic (H1N1) 2009 influenza viruses (A(H1N1)pdm09) ...were frequently reported in severe influenza in humans and mice. Their impact on viral pathogenicity and the course of influenza has been discussed controversially and the underlying mechanism remained unclarified. In the present study, BALB/c mice, infected with the once mouse lung- and cell-passaged A(H1N1)pdm09 isolate A/Jena/5258/09 (mpJena/5258), developed severe pneumonia. From day 2 to 3 or 4 post infection (p.i.) symptoms (body weight loss and clinical score) continuously worsened. After a short disease stagnation or even recovery phase in most mice, severity of disease further increased on days 6 and 7 p.i. Thereafter, surviving mice recovered. A 45 times higher virus titer maximum in the lung than in the trachea on day 2 p.i. and significantly higher tracheal virus titers compared to lung on day 6 p.i. indicated changes in the organ tropism during infection. Sequence analysis revealed an HA-222D/G polymorphism. HA-D222 and HA-G222 variants co-circulated in lung and trachea. Whereas, HA-D222 variant predominated in the lung, HA-G222 became the major variant in the trachea after day 4 p.i. This was accompanied by lower neutralizing antibody titers and broader receptor recognition including terminal sialic acid α-2,3-linked galactose, which is abundant on mouse trachea epithelial cells. Plaque-purified HA-G222-mpJena/5258 virus induced severe influenza with maximum symptom on day 6 p.i. These results demonstrated for the first time that HA-222D/G quasispecies of A(H1N1)pdm09 caused severe biphasic influenza because of fast viral intra-host evolution, which enabled partial antibody escape and minor changes in receptor binding.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Severe influenza associated with strong symptoms and lung inflammation can be caused by intra-host evolution of quasispecies with aspartic acid or glycine in hemagglutinin position 222 (HA-222D/G; H1 ...numbering). To gain insights into the dynamics of host response to this coevolution and to identify key mechanisms contributing to copathogenesis, the lung transcriptional response of BALB/c mice infected with an A(H1N1)pdm09 isolate consisting HA-222D/G quasispecies was analyzed from days 1 to 12 post infection (p.i). At day 2 p.i. 968 differentially expressed genes (DEGs) were detected. The DEG number declined to 359 at day 4 and reached 1001 at day 7 p.i. prior to recovery. Interestingly, a biphasic expression profile was shown for the majority of these genes. Cytokine assays confirmed these results on protein level exemplarily for two key inflammatory cytokines, interferon gamma and interleukin 6. Using a reverse engineering strategy, a regulatory network was inferred to hypothetically explain the biphasic pattern for selected DEGs. Known regulatory interactions were extracted by Pathway Studio 9.0 and integrated during network inference. The hypothetic gene regulatory network revealed a positive feedback loop of Ifng, Stat1, and Tlr3 gene signaling that was triggered by the HA-G222 variant and correlated with a clinical symptom score indicating disease severity.
With the emergence of oseltamivir-resistant influenza viruses and in view of a highly pathogenic flu pandemic, it is important to develop new anti-influenza agents. Here, the development of ...neuraminidase (NA) inhibitors that were designed to overcome resistance mechanisms along with unfavorable pharmacokinetic (PK) properties is described. Several 5-guanidino- and 5-amidino-based oseltamivir derivatives were synthesized and profiled for their anti-influenza activity and in vitro and in vivo PK properties. Amidine 6 and guanidine 7 were comparably effective against a panel of different A/H1N1 and A/H3N2 strains and also inhibited mutant A/H1N1 neuraminidase. Among different prodrug strategies pursued, a simple amidoxime ethyl ester (9) exhibited a superior PK profile with an oral bioavailability of 31% (rats), which is comparable to oseltamivir (36%). Thus, bioisosteric replacement of the 5-guanidine with an acetamidinein the form of its N-hydroxy prodrugsuccessfully tackled the two key limitations of currently used NA inhibitors, as exemplified with oseltamivir.
The emergence of new influenza viruses like the pandemic H1N1 influenza A virus in 2009 (A(H1N1)pdm09) with unpredictable difficulties in vaccine coverage and established antiviral treatment ...protocols emphasizes the need of new murine models to prove the activity of novel antiviral compounds in vivo. The aim of the present study was to develop a small-scale mathematical model based on easily attainable experimental data to explain differences in influenza kinetics induced by different virus strains in mice. To develop a three-dimensional ordinary differential equation model of influenza dynamics, the following variables were included: (i) viral pathogenicity (P), (ii) antiviral immune defense (D), and (iii) inflammation due to pro-inflammatory response (I). Influenza virus-induced symptoms (clinical score S) in mice provided the basis for calculations of P and I. Both, mono- and biphasic course of mild to severe influenza induced by three clinical A(H1N1)pdm09 strains and one European swine H1N2 virus were comparatively and quantitatively studied by fitting the mathematical model to the experimental data. The model hypothesizes reasons for mild and severe influenza with mono- as well as biphasic course of disease.
According to modeling results, the second peak of the biphasic course of infection is caused by inflammation. The parameters (i) maximum primary pathogenicity, (ii) viral infection rate, and (iii) rate of activation of the immune system represent most important parameters that quantitatively characterize the different pattern of virus-specific influenza kinetics.
There are currently no drugs available for the treatment of enterovirus (EV)‐induced acute and chronic diseases such as the common cold, meningitis, encephalitis, pneumonia, and myocarditis with or ...without consecutive dilated cardiomyopathy. Here, we report the discovery and characterization of pyrazolopyrimidines, a well‐tolerated and potent class of novel EV inhibitors. The compounds inhibit the replication of a broad spectrum of EV in vitro with IC50 values between 0.04 and 0.64 μM for viruses resistant to pleconaril, a known capsid‐binding inhibitor, without affecting cytochrome P450 enzyme activity. Using virological and genetics methods, the viral capsid was identified as the target of the most promising, orally bioavailable compound 3‐(4‐trifluoromethylphenyl)amino‐6‐phenylpyrazolo3,4‐dpyrimidine‐4‐amine (OBR‐5‐340). Its prophylactic as well as therapeutic application was proved for coxsackievirus B3‐induced chronic myocarditis in mice. The favorable pharmacokinetic, toxicological, and pharmacodynamics profile in mice renders OBR‐5‐340 a highly promising drug candidate, and the regulatory nonclinical program is ongoing.
Curing the common cold! A cluster of pyrazolopyrimidines with potent broad‐spectrum activity against enteroviruses was discovered. Extensive structure–property relationship analyses led to the identification of 3‐(4‐trifluoromethyl‐phenyl)amino‐6‐phenylpyrazolo3,4‐dpyrimidine‐4‐amine, shown to be a blocker of the viral capsid protein, as a lead compound for drug development with favorable physicochemical, pharmacokinetic, and toxicological properties.
The pathogenicity of influenza A and B viruses depends on the function of influenza neuraminidase (NA). Emerging resistant influenza A viruses of subtype H1N1 increasingly challenge the effectiveness ...of established NA inhibitors. Recent computational studies have indicated several weak points of NA that can be exploited for rational inhibitor design to conquer this imminent threat, such as the opening of the binding pocket due to the flexibility of the 150-, 245- and 430-loops.
We employed shape-focused virtual screening based on a recently discovered lead compound, katsumadain A, to identify novel promising compounds with significant inhibitory efficacy on NA and resistance-breaking capacity on oseltamivir-resistant strains. A potential binding mode of these compounds was derived employing ligand-based techniques and protein-ligand docking using representative protein conformations selected from molecular dynamics simulations.
Five novel compounds were identified by virtual screening. Their IC(50) values, determined in chemiluminescence-based NA inhibition assays, are in the range of 0.18-17 µM. In particular, artocarpin exhibits high affinity toward three H1N1 oseltamivir-sensitive influenza A viruses. It also inhibits the NA of an oseltamivir-resistant H1N1 isolate.
The amino acid substitution of aspartic acid to glycine in hemagglutinin (HA) in position 222 (HA-D222G) as well as HA-222D/G polymorphism of pandemic (H1N1) 2009 influenza viruses (A(H1N1)pdm09) ...were frequently reported in severe influenza in humans and mice. Their impact on viral pathogenicity and the course of influenza has been discussed controversially and the underlying mechanism remained unclarified. In the present study, BALB/c mice, infected with the once mouse lung- and cell-passaged A(H1N1)pdm09 isolate A/Jena/5258/09 (mpJena/5258), developed severe pneumonia. From day 2 to 3 or 4 post infection (p.i.) symptoms (body weight loss and clinical score) continuously worsened. After a short disease stagnation or even recovery phase in most mice, severity of disease further increased on days 6 and 7 p.i. Thereafter, surviving mice recovered. A 45 times higher virus titer maximum in the lung than in the trachea on day 2 p.i. and significantly higher tracheal virus titers compared to lung on day 6 p.i. indicated changes in the organ tropism during infection. Sequence analysis revealed an HA-222D/G polymorphism. HA-D222 and HA-G222 variants co-circulated in lung and trachea. Whereas, HA-D222 variant predominated in the lung, HA-G222 became the major variant in the trachea after day 4 p.i. This was accompanied by lower neutralizing antibody titers and broader receptor recognition including terminal sialic acid alpha -2,3-linked galactose, which is abundant on mouse trachea epithelial cells. Plaque-purified HA-G222-mpJena/5258 virus induced severe influenza with maximum symptom on day 6 p.i. These results demonstrated for the first time that HA-222D/G quasispecies of A(H1N1)pdm09 caused severe biphasic influenza because of fast viral intra-host evolution, which enabled partial antibody escape and minor changes in receptor binding.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Family plays an important role in the lives of unaccompanied minors.•Unaccompanied minors employ diverse means of staying in touch with their transnational families.•Transnational family ...relationships can have an impact on unaccompanied minors’ daily lives.•Social work should reflect on transnational family and social networks as a potential resource for unaccompanied minors.•Transnational family relationships should be considered in research and practice.
Research on unaccompanied minors (UMs) has identified the physical separation from family as a main stressor despite increased opportunities, via Information and Communication Technologies (ICTs), for maintaining transnational family life across geographical borders.
The aim of the study is to synthesize previous research on the transnational family relationships of UMs from the perspective of the children.
A systematic literature review following the Preferred Reporting Items for Standards for Systematic Reviews and Meta-Analysis Protocols was carried out. The databases Web of Science, PsycINFO, Psyndex, and Pubmed/Medline were systematically searched. Reports from International Non-Governmental Organizations (INGOs) were screened manually. Two hundred fifty-six full-texts were identified and screened.
Twelve qualitative and two quantitative studies met inclusion criteria and provided information on transnational family connections and the importance of the family for UMs. Studies addressed the following themes: the importance of the family, contact and maintenance of transnational relationships, the role of ICTs, the impact of family life on UMs' psychosocial wellbeing, and the hope for reunification.
This review underscores the continued importance of the family to displaced UMs and highlights the need to foster and examine transnational connections in further research and practice with UMs.
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