Economic and epidemiological impact of dengue illness over 16 years from a public health system perspective in Brazil to inform future health policies including the adoption of a dengue vaccine

Introduction: Dengue is a serious global health problem endemic in Brazil. Consequently, our aim was to measure the costs and disease burden of symptomatic dengue infections in Brazil from the perspective of the Brazilian Public Health System (SUS) between 2000 and 2015 using Brazilian public health system databases. Specific age group incidence estimates were used to calculate the disability-adjusted life years (DALYs) to gain a better understanding of the disease burden. Areas covered: SUS spent almost USD159 million and USD10 million to treat dengue and severe dengue, respectively, between 2000-2015. This is principally hospitalization costs with the majority of patients self-treated at home with minor symptoms. The average notification rate for dengue was 273 per 100,000 inhabitants and 3 per 100,000 for severe dengue, with annual DALYs estimates ranging between 72.35 to 6,824.45 during the 16 years. Expert commentary: The epidemiological and morbidity burden associated with dengue is substantial in Brazil, with costs affected by the fact that most patients self-treat at home with these costs not included in SUS. The Brazilian government urgently needs to proactively evaluate the real costs and clinical benefits of any potential dengue vaccination program by the National Immunization Program to guide future decision making

Binding mode of the activity-modulating C-terminal segment of NS2B to NS3 in the dengue virus NS2B–NS3 protease

The two-component dengue virus NS2B–NS3 protease (NS2B–NS3pro) is an established drug target but inhibitor design is hampered by uncertainties about its 3D structure in solution. Crystal structures reported very different conformations for the functionally important C-terminal segment of the NS2B cofactor (NS2Bc), indicating open and closed conformations in the absence and presence of inhibitors, respectively. An earlier NMR study in solution indicated that a closed state is the preferred conformation in the absence of an artificial linker engineered between NS2B and NS3pro. To obtain direct structural information on the fold of unlinked NS2B–NS3pro in solution, we tagged NS3pro with paramagnetic tags and measured pseudocontact shifts by NMR to position NS2Bc relative to NS3pro. NS2Bc was found to bind to NS3pro in the same way as reported in a previously published model and crystal structure of the closed state. The structure is destabilized, however, by high ionic strength and basic pH, showing the importance of electrostatic forces to tie NS2Bc to NS3pro. Narrow NMR signals previously thought to represent the open state are associated with protein degradation. In conclusion, the closed conformation of the NS2B–NS3 protease is the best model for structure-guided drug design

The effects of combinatorial chemistry and technologies on drug discovery and biotechnology : A mini review

The review will focus on the aspects of combinatorial chemistry and technologies that are more relevant in the modern pharmaceutical process. An historical, critical introduction is followed by three chapters, dealing with the use of combinatorial chemistry/high throughput synthesis in medicinal chemistry; the rational design of combinatorial libraries using computer-assisted combinatorial drug design; and the use of combinatorial technologies in biotechnology. The impact of "combinatorial thinking" in drug discovery in general, and in the examples reported in details, is critically discussed. Finally, an expert opinion on current and future trends in combinatorial chemistry and combinatorial technologies is provided

New Binding Site Conformations of the Dengue Virus NS3 Protease Accessed by Molecular Dynamics Simulation

International audienceDengue fever is caused by four distinct serotypes of the dengue virus (DENV1-4), and is estimated to affect over 500 million people every year. Presently, there are no vaccines or antiviral treatments for this disease. Among the possible targets to fight dengue fever is the viral NS3 protease (NS3PRO), which is in part responsible for viral processing and replication. It is now widely recognized that virtual screening campaigns should consider the flexibility of target protein by using multiple active conformational states. The flexibility of the DENV NS3PRO could explain the relatively low success of previous virtual screening studies. In this first work, we explore the DENV NS3PRO conformational states obtained from molecular dynamics (MD) simulations to take into account protease flexibility during the virtual screening/docking process. To do so, we built a full NS3PRO model by multiple template homology modeling. The model comprised the NS2B cofactor (essential to the NS3PRO activation), a glycine flexible link and the proteolytic domain. MD simulations had the purpose to sample, as closely as possible, the ligand binding site conformational landscape prior to inhibitor binding. The obtained conformational MD sample was clustered into four families that, together with principal component analysis of the trajectory, demonstrated protein flexibility. These results allowed the description of multiple binding modes for the Bz-Nle-Lys-Arg-Arg-H inhibitor, as verified by binding plots and pair interaction analysis. This study allowed us to tackle protein flexibility in our virtual screening campaign against the dengue virus NS3 proteas

Applications of paramagnetic NMR spectroscopy in drug discovery

NMR spectroscopy of proteins with paramagnetic metal ions, first performed with metalloproteins, is a unique technique to obtain long-range distance information for three-dimensional structure determinations. This thesis focuses on developing applications of paramagnetic NMR spectroscopy, particularly pseudocontact shifts, in drug discovery. The two-component dengue virus NS2B-NS3 protease (NS2B-NS3pro) from serotype 2 is a well-established drug target, but drug development has been hampered for many years by lack of structural information. In earlier work, pseudocontact shifts (PCSs) induced by lanthanide binding tags at multiple sites had successfully been used to determine the closed conformation of NS2B in the presence of a small inhibitor molecule. Subsequently, PCSs were used to prove that an unlinked construct of NS2B-NS3pro exists predominately in the closed conformation in solution, showing that the open conformation observed previously is an artefact generated by a covalent link between NS2B and NS3 (Paper 1). Next, PCSs generated for NS2B, NS3pro and bovine pancreatic trypsin inhibitor (BPTI) were used to show that the C-terminal segment of NS2B remains in the closed conformation in the presence of BPTI, correcting a crystallographic artefact (Paper 2). The work described in Papers 1 and 2 confirmed that the closed conformation of dengue virus NS2B-NS3pro is the best model for structure-guided drug design. As the sensitivity of NMR spectra of dynamic proteins, such as the dengue virus protease, is compromised by excessive line broadening, alternative NMR tags were sought. O-tert-butyltyrosine incorporated in proteins proved to be an outstanding NMR probe for conformational studies of high-molecular-weight systems and measurement of submicromolar ligand binding affinities in one-dimensional 1H-NMR spectra without any isotope labelling (Paper 3). A tert-butyl probe was also introduced into a tightly binding lead compound against the dengue virus protease. Measurement of ligand PCSs from intense intramolecular NOESY cross-peaks with the tert-butyl group allowed positioning of the ligand on the protein with respect to the paramagnetic centre, while strong intermolecular NOEs validated the structural model of the complex established with the use of PCSs (Paper 4). In summary, the paramagnetic NMR approach, demonstrated on the dengue virus NS2B-NS3 protease, presents a broadly applicable and elegant way for structure-guided drug design at atomic resolution

Caracterização do efeito de substâncias naturais extraídas de macroalgas marinhas e de um painel de substâncias sintéticas na inibição da infecção pelo virus da dengue em modelo in vitro

Orientadora : Drª. Claudia Nunes Duarte dos SantosCo-orientador : Dr. Juliano BordignonTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Biologia Celular e Molecular. Defesa: Curitiba, 25/02/2014Inclui referênciasÁrea de concentraçãoResumo: A dengue é um problema de saúde pública mundial. Apesar do importante impacto clínico e social, não existem vacinas ou terapias específicas para a prevenção ou o tratamento da infecção pelo vírus da dengue (DENV). Considerando o exposto, a pesquisa pela descoberta de drogas para dengue é de extrema importância. Além disso, extratos naturais de origem marinha podem fornecer estruturas químicas novas e diversas com atividade biológica potente que necessitam ser avaliadas, assim como substâncias químicas sintéticas. Neste estudo foi proposta uma abordagem sem alvo específico para a descoberta de drogas contra dengue, baseado em um novo, rápido e econômico ELISA em célula. O in situ ELISA foi padronizado e validado para a linhagem celular Huh7.5 infectada com os quatro sorotipos do DENV, entre eles isolados clínicos e cepas adaptadas de laboratório. Análises estatísticas mostraram um valor médio de S/B de 7,2 e fator-Z de 0,62, demonstrando a consistência e segurança do ensaio. Um painel de quinze extratos de algas foi triado com a concentração não tóxica determinada pelos ensaios de MTT e vermelho neutro. Oito extratos de algas foram capazes de reduzir a infecção pelo DENV para pelo menos um sorotipo testado. Quatro extratos (Phaeophyta: Canistrocarpus cervicornis, Padina gymnospora; Rhodophyta: Palisada perforata; Chlorophyta: Caulerpa racemosa) foram escolhidos para uma avaliação mais aprofundada, e estudos de tempo de adição apontam que eles podem atuar em estágios iniciais do ciclo de infecção, como adsorção ou internalização. Além disso, foi realizada a triagem antiviral com 49 substâncias químicas sintéticas, das quais oitos antraquinonas apresentaram atividade anti-dengue em linhagem celular Huh7.5 e foram testadas em culturas de células mononucleares do sangue periférico de doadores humanos saudáveis. Os tratamentos com TAC02, TAC12 e LSF23 foram capazes de diminuir a porcentagem de células infectadas a níveis comparados ao IFN-a 2A, usado como substância referência. Dessa forma, foi apresentado um método confiável, de baixo custo e fácil execução para a triagem de substâncias com atividade anti-DENV, com resultados promissores partindo de produtos naturais e substâncias químicas sintéticas.Abstract: A dengue é um problema de saúde pública mundial. Apesar do importante impacto clínico e social, não existem vacinas ou terapias específicas para a prevenção ou o tratamento da infecção pelo vírus da dengue (DENV). Considerando o exposto, a pesquisa pela descoberta de drogas para dengue é de extrema importância. Além disso, extratos naturais de origem marinha podem fornecer estruturas químicas novas e diversas com atividade biológica potente que necessitam ser avaliadas, assim como substâncias químicas sintéticas. Neste estudo foi proposta uma abordagem sem alvo específico para a descoberta de drogas contra dengue, baseado em um novo, rápido e econômico ELISA em célula. O in situ ELISA foi padronizado e validado para a linhagem celular Huh7.5 infectada com os quatro sorotipos do DENV, entre eles isolados clínicos e cepas adaptadas de laboratório. Análises estatísticas mostraram um valor médio de S/B de 7,2 e fator-Z de 0,62, demonstrando a consistência e segurança do ensaio. Um painel de quinze extratos de algas foi triado com a concentração não tóxica determinada pelos ensaios de MTT e vermelho neutro. Oito extratos de algas foram capazes de reduzir a infecção pelo DENV para pelo menos um sorotipo testado. Quatro extratos (Phaeophyta: Canistrocarpus cervicornis, Padina gymnospora; Rhodophyta: Palisada perforata; Chlorophyta: Caulerpa racemosa) foram escolhidos para uma avaliação mais aprofundada, e estudos de tempo de adição apontam que eles podem atuar em estágios iniciais do ciclo de infecção, como adsorção ou internalização. Além disso, foi realizada a triagem antiviral com 49 substâncias químicas sintéticas, das quais oitos antraquinonas apresentaram atividade anti-dengue em linhagem celular Huh7.5 e foram testadas em culturas de células mononucleares do sangue periférico de doadores humanos saudáveis. Os tratamentos com TAC02, TAC12 e LSF23 foram capazes de diminuir a porcentagem de células infectadas a níveis comparados ao IFN-a 2A, usado como substância referência. Dessa forma, foi apresentado um método confiável, de baixo custo e fácil execução para a triagem de substâncias com atividade anti-DENV, com resultados promissores partindo de produtos naturais e substâncias químicas sintéticas