Loading...
Publication
Fighting Dengue and Zika using novel Glycodendrimer-encapsulated metal nanoparticles as viral inhibitors"
| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 3.05 MB | Adobe PDF |
Abstract(s)
Os graves sintomas causados por doenças infeciosas, como, as febres dengue e zika são
considerados nos dias de hoje um problema global que deve ser devidamente avaliado e
combatido.1 Com o intuito de fazer face às complicações associadas a estas duas enfermidades
reemergentes, esforços têm sido direcionados para a descoberta de novos agentes antivirais,
capazes de impedir a transmissão dos agentes causadores dessas patologias. Uma das estratégias
assenta em saturar o recetor que promove a entrada destas partículas virais – DC-SIGN – nas
células hospedeiras.2 O recetor do tipo lectina, o DC-SIGN, é ativado por carbohidratos,
monoméricos ou não. As semelhanças com os sacarídeos e as respetivas propriedades,
despertaram recentemente o interesse da comunidade científica para a descoberta de
glicomiméticos, moléculas especificamente capazes de serem utilizadas como substitutas das
originais. Entretanto, estudos mostraram que o ácido chiquímico (SA) é uma boa opção para
substituir os sacarídeos envolvidos na ativação do DC-SIGN. O presente trabalho teve como
objetivo a criação de um sistema eficaz na captação da inigualável multivalência dos
dendrímeros, no caso presente, os poly(amidoamina) (PAMAM) e das propriedades do SA,
enquanto glicomimético. Nesse sentido, duas gerações de PAMAM (G4 e G5) foram
funcionalizadas com SA por via do acoplamento mediado por carbodiimida EDC/NHS,
obtendo-se assim PAMAM funcionalizados com SA (SAGx). Adicionalmente, e uma vez que
as nanopartículas metálicas são conhecidas pela sua atividade antiviral, após purificação
daqueles dendrímeros, procedeu-se à redução de cobre, mediada pelo ácido ascórbico. A
caracterização dos complexos foi efetuada através de espectroscopias de Ultravioleta-Visível
(UV-Vis), fluorescência, e de Infravermelho por Reflexão Total Atenuada (ATR-FTIR), ainda
Dynamic Light Scattering (DLS), Ressonância Magnética Nuclear de protão (1H RMN),
Microscopia Electrónica de Varrimento (SEM) e Inductively coupled plasma optical emission
spectroscopy (ICP-OES). Por fim, foi testada a citotoxicidade dos compostos SAGx, num
intervalo de concentrações, em células HEK 293T. Das concentrações utilizadas verificou-se
que a viabilidade celular sofreu um decréscimo acentuado a partir dos 400 µM para o SAG4.
Em contrapartida, não se verificou grande variação para o SAG5, mesmo utilizando a
concentração de trabalho máxima, 500 µM.
Due to their mild-to-severe symptoms, dengue and zika fevers are considered a global problem that must be assessed and acted upon.1 In order to overcome the problems associated with these two re-emergent infectious diseases, research has focused on developing antiviral therapeutic agents that inhibit disease transmission. One strategy lies in blocking the dendritic cell-specific ICAM3-grabbing nonintegrin (DC-SIGN) receptor that the dengue virus (DENV) and the zika virus (ZIKV) both use to promote their entry into host cells. Being a lectin-type receptor, DC SIGN is triggered by carbohydrate moieties. Recently, because of similarities with saccharides, great efforts have been placed into discovering new glycomimetics that can be used as sugar alternatives. Previous studies have shown shikimic acid (SA) to be a good glycomimetic contender in targeting the DC-SIGN receptor.2 This work aimed to develop a system that effectively targets DC-SIGN by taking advantage of the unique multivalency and conjugation versatility of the poly(amidoamine) (PAMAM) dendrimers and combine it with the properties of SA. Amine-terminated generation four (G4.NH2) and generation five (G5.NH2) PAMAM dendrimers served as scaffolds to conjugate SA via the EDC/NHS coupling method to obtain the corresponding SA-functionalized dendrimers (i.e., SAG4 and SAG5). The formed conjugates were then used to as templates to prepare copper dendrimer entrapped nanoparticles (Cu DENPs). All of the complexes underwent characterisation via Ultraviolet-Visible (UV-Vis) spectroscopy, fluorescence spectroscopy, Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), Dynamic Light Scattering (DLS), proton Nuclear Magnetic Resonance ( 1H NMR), Scanning Electron Microscopy (SEM) and ICP. In vitro analysis of the cytotoxic effects of the SAG4 and SAG5 compounds obtained from the first reaction step was assessed in HEK 293T cells. Having tested a wide range of different glycomimetic concentrations, it was found that cell viability decreased significantly when using a concentration of 400 µM for SAG4. For SAG5, on the other hand, no significant impact on cell viability was observed, even when using a 500 µM concentration.
Due to their mild-to-severe symptoms, dengue and zika fevers are considered a global problem that must be assessed and acted upon.1 In order to overcome the problems associated with these two re-emergent infectious diseases, research has focused on developing antiviral therapeutic agents that inhibit disease transmission. One strategy lies in blocking the dendritic cell-specific ICAM3-grabbing nonintegrin (DC-SIGN) receptor that the dengue virus (DENV) and the zika virus (ZIKV) both use to promote their entry into host cells. Being a lectin-type receptor, DC SIGN is triggered by carbohydrate moieties. Recently, because of similarities with saccharides, great efforts have been placed into discovering new glycomimetics that can be used as sugar alternatives. Previous studies have shown shikimic acid (SA) to be a good glycomimetic contender in targeting the DC-SIGN receptor.2 This work aimed to develop a system that effectively targets DC-SIGN by taking advantage of the unique multivalency and conjugation versatility of the poly(amidoamine) (PAMAM) dendrimers and combine it with the properties of SA. Amine-terminated generation four (G4.NH2) and generation five (G5.NH2) PAMAM dendrimers served as scaffolds to conjugate SA via the EDC/NHS coupling method to obtain the corresponding SA-functionalized dendrimers (i.e., SAG4 and SAG5). The formed conjugates were then used to as templates to prepare copper dendrimer entrapped nanoparticles (Cu DENPs). All of the complexes underwent characterisation via Ultraviolet-Visible (UV-Vis) spectroscopy, fluorescence spectroscopy, Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), Dynamic Light Scattering (DLS), proton Nuclear Magnetic Resonance ( 1H NMR), Scanning Electron Microscopy (SEM) and ICP. In vitro analysis of the cytotoxic effects of the SAG4 and SAG5 compounds obtained from the first reaction step was assessed in HEK 293T cells. Having tested a wide range of different glycomimetic concentrations, it was found that cell viability decreased significantly when using a concentration of 400 µM for SAG4. For SAG5, on the other hand, no significant impact on cell viability was observed, even when using a 500 µM concentration.
Description
Keywords
Glycodendrimers CuDENPs DC-SIGN Shikimic acid HEK 293 T Cells Glicomiméticos Nanopartículas de cobre Ácido chiquímico Células HEK 293T Dengue Zika Nanochemistry and Nanomaterials . Faculdade de Ciências Exatas e da Engenharia