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Os hantavírus, membros da família Bunyaviridae, são os agentes infecciosos responsáveis pela Febre Hemorrágica com Síndrome Renal e pela Síndrome Cardiopulmonar por Hantavírus. São vírus com genoma constituído por três segmentos de RNA fita simples, de polaridade negativa, designados como S, M e L, que codificam, respectivamente, a nucleoproteína, as glicoproteínas G1 e G2 e a RNA polimerase dependente de RNA. Com o objetivo de estudar a montagem de pseudopartículas quiméricas de hantavírus, a proteína N do vírus Araraquara e as glicoproteínas G1 e G2 do vírus Andes foram expressas em sistema baculovírus. A microscopia confocal mostrou a colocalização das proteínas G1 e G2 com a proteína N. Pelos ensaios de imunoprecipitação e de centrifugação em gradiente de sacarose, foi observada a interação entre as proteínas N, G1 e G2. Nas análises por microscopia eletrônica de transmissão foi observada a montagem do pseudo-hantavírus quimera, com morfologia semelhante ao do vírion. O pseudo-hantavírus quimera obtido neste estudo poderá, no futuro, ser utilizado em estudos imunológicos, estruturais e morfológicos. / Hantaviruses, members of the Bunyaviridae family, are the infectious agents responsible for Hemorrhagic Fever with Renal Syndrome and the Hantavirus Cardiopulmonary Syndrome. The viral genome is composed by three segments of single-stranded negative-sense RNA, designated as S, M and L, which encode, respectively, the nucleoprotein, the G1 and G2 glycoproteins, and the RNA-dependent RNA polymerase. In order to study the assembly of a chimeric hantavirus-like particle, the Araraquara nucleoprotein and the Andes glycoproteins were expressed in a baculovirus system. Confocal microscopy showed the colocalization of G1 and G2 proteins with the N protein. Immunoprecipitation assay and sucrose density gradient showed the interaction among N, G1 and G2 proteins. The transmission electron microscopy showed the hantavirus-like particle with the same morphology of the virion. The chimeric hantavirus-like particle produced in this study could be used, in the future, in immunological, structural and morphological studies.

The human kallikrein family is a family of proteolytic enzymes, classified as serine proteases, that derive from chromosome 19, locus 13.3-13.4. These enzymes are widespread in pathophysiological processes such as cancer and neurodegenerative diseases; hence studies of catalytic sites and inhibitors are important in relation to the longer term of design of therapeutic drugs. One member of the family, human kallikrein 4 (hK4) which is thought to carry out crucial functions in the prostate, was expressed in this study as a secreted protein in a baculovirus expression system, bearing a His-tag and V5-epitope that were used for purification and detection respectively. Its mass was estimated to be 35kDa, ~2kDa less than the equivalent product expressed in monkey kidney cells. The protein was purified to 50-90% purity with a yield of 0.93mg/L-4.8mg/L based on methods derived from computational prediction of its properties, such as pI. Computational analysis was extended by applying high-performing computing techniques, such as molecular dynamics, and flexible ligand docking, to predict antigenic regions, the likely substrate specificity and putative inhibitors. These results show that hK4 has a loop, between Leu83-Ser94 that shows promise as a specific segment that can be exploited for generation of antibodies. Preferred substrates were also predicted to bear hydrophobic residues at the P'-region of the scissile bond and amphiphilic residues at the P-region. At the S-region, hK4 potentially involves its unique PLYH-motif in recognizing the P4/P5 position from the substrate. Flexible ligand-docking studies indicate that hK4 can be inhibited by inhibitors that carry a modified bulky hydrophobic sidechain with a guanidinium group at the P1-position and its own putative autoactivation region residues at the P2, P1' and P2' position. The computational study was extended to other members of the kallikrein family, predicting distinctions between these that could be used for future studies. These results show that 8 of the fifteen kallikrein members are very homologous in terms of specificity bearing typical trypsinlike activity and specificity, except for hK2, hK3, hK4, hK5, hK7, hK9, hK15 that retain certain distinct signatures in the binding pocket in terms of secondary specificity. The principles of substrate-specificity analysis that were developed were further applied on three metzincins, MMP-3, ADAM-9 and ADAM-10. These three enzymes are metalloproteases, which are involved in tissue remodeling, intracellular signalling and cell-to-cell mediation. The substrate-specificity analysis was carried out on all three metzincins using the structure of a crystallized complex of the MMP-3 enzyme with the TIMP-1 natural inhibitor as template. In this specific enzyme-substrate complex, the challenge was to model and suggest a possible orientation of the P-region, which is not known. The interactions on the P/S-region are therefore unclear and need to be clarified. In order to suggest the arrangement of the enzyme-substrate complex and the undefined S-subsites, four new residues were added in an extended beta-sheet conformation to the P1' residue (derived originally from the TIMP-1 inhibitor) to create a full-length modeled substrate spanning P4'-P4. This new modeled region, in particular, was bound through backbone H-bonds with the enzyme at position 169 (MMP nomenclature) suggesting a new crucial residue for substrate binding, and satisfied steric and chemical restraints in the S'-region of the enzyme. This modeling approach also indicated a putative presence of an S2/S3-pocket on these metzincins which is composed of different residues for MMP-3, ADAM-9 and ADAM-10, and which could prove useful for future drug design projects. Furthermore, the data argue against the involvement of a polarizable water molecule in catalysis, a mechanism that has been postulated by various groups. A new catalytic mechanism is suggested to involve an oxyanion anhydride transition state. This study is a demonstration of the power of combining bioinformatics with wet-lab biochemistry.

Os hantavírus, membros da família Bunyaviridae, são os agentes infecciosos responsáveis pela Febre Hemorrágica com Síndrome Renal e pela Síndrome Cardiopulmonar por Hantavírus. São vírus com genoma constituído por três segmentos de RNA fita simples, de polaridade negativa, designados como S, M e L, que codificam, respectivamente, a nucleoproteína, as glicoproteínas G1 e G2 e a RNA polimerase dependente de RNA. Com o objetivo de estudar a montagem de pseudopartículas quiméricas de hantavírus, a proteína N do vírus Araraquara e as glicoproteínas G1 e G2 do vírus Andes foram expressas em sistema baculovírus. A microscopia confocal mostrou a colocalização das proteínas G1 e G2 com a proteína N. Pelos ensaios de imunoprecipitação e de centrifugação em gradiente de sacarose, foi observada a interação entre as proteínas N, G1 e G2. Nas análises por microscopia eletrônica de transmissão foi observada a montagem do pseudo-hantavírus quimera, com morfologia semelhante ao do vírion. O pseudo-hantavírus quimera obtido neste estudo poderá, no futuro, ser utilizado em estudos imunológicos, estruturais e morfológicos. / Hantaviruses, members of the Bunyaviridae family, are the infectious agents responsible for Hemorrhagic Fever with Renal Syndrome and the Hantavirus Cardiopulmonary Syndrome. The viral genome is composed by three segments of single-stranded negative-sense RNA, designated as S, M and L, which encode, respectively, the nucleoprotein, the G1 and G2 glycoproteins, and the RNA-dependent RNA polymerase. In order to study the assembly of a chimeric hantavirus-like particle, the Araraquara nucleoprotein and the Andes glycoproteins were expressed in a baculovirus system. Confocal microscopy showed the colocalization of G1 and G2 proteins with the N protein. Immunoprecipitation assay and sucrose density gradient showed the interaction among N, G1 and G2 proteins. The transmission electron microscopy showed the hantavirus-like particle with the same morphology of the virion. The chimeric hantavirus-like particle produced in this study could be used, in the future, in immunological, structural and morphological studies.

Magister Scientiae (Medical Bioscience) - MSc(MBS) / Insect-derived baculoviruses have been used extensively as a safe and versatile research model for transgenic protein expression. Preclinical studies have revealed the promising potential of Baculoviruses as a delivery vector for a variety of therapeutic applications, including vaccination, tissue engineering and cancer treatments. Coronaviruses are enveloped viruses containing linear, non-segmented ribonucleic acid. Human coronavirus NL63 was first discovered in the Netherlands in January 2004, where a 7-month-old girl presented with an acute respiratory tract infection that was later established to predominantly infect infants, the elderly and immunocompromised individuals.

Com o objetivo de estudar a interação do HAdV-41 com células permissivas, primeiramente foi observada a cinética de infecção do HAdV-41 em células HEK-293, durante 7 dias. A seguir, as culturas foram analisadas por MCVL e por MET. O HAdV-41 apresentou um ciclo replicativo lento com liberação da progênie viral por mecanismo não lítico. A seguir, com o intuíto de verificar a participação da proteina FC do HAdV-41 nas etapas de entrada nas células HEK-293 e CaCo2, obteve-se os dodecaedros recombinantes (DR) em células High five (base-Ad3, base-Ad3+FC-Ad41, base-Ad3+FL-Ad41, baseRGEHS-Ad3+FCAd41 e base-Ad3+FAd3). Esses dodecaedros foram inoculados em células HEK-293 e CaCo2. Após a análise por MCVL, observou-se que a proteína FC talvez não desempenhe função na entrada do DR nas células estudadas. A seguir, uma alíquota do DR base-Ad3+FC-Ad41 foi digerida com a enzima pepsina e analisada por WB. Notou-se que a FC sofreu proteólise. Acredita-se que essa proteólise seja necessária para o reconhecimento de receptores no trato gastro-intestinal. Esses resultados fornecerão subsídeos para o desenvolvimento de vetores de terapia gênica direcionada para o epitélio intestinal e vetores vacinais administrados por via oral. / Our objective was study the interaction between HAdV-41 and permissive cells. First, it was observed the kinetic of infection between HAdV-41 and HEK-293 cells, for 7 days. Second, the cultures were analyzed by CLSM and by TEM. The HAdV-41 showed a slower replicative cycle with release of viral progeny by non-lytic mechanisms. In order to verify the participation of SF protein of the HAdV-41 during the phases of entry in HEK-293 and CaCo2 cells, we producted recombinant dodecahedrons (DR) in high five cells (base-Ad3, base-Ad3+SF-Ad41, base-Ad3+SF-Ad41, baseRGEHS-Ad3+SFAd41 and base-Ad3+FAd3). These decahedrons were inoculated in HEK-293 and CaCo2 cells. After analysis with CLSM, observed that SF protein may not have a role in dodecahedron entry in the cells studied. Next, recombinant dodecahedrons base-Ad3+SF-Ad41 and base-Ad3 were digested with pepsin and analyzed by WB. We observed proteolysis of the SF. We believe that this proteolysis may be necessary for the recognition of receptors in intestinal cells. The results obtained will be the base for the development of gene-therapy vectors directed to intestinal epithelium, as well as orally administered vaccine vectors.

Com o objetivo de estudar a interação do HAdV-41 com células permissivas, primeiramente foi observada a cinética de infecção do HAdV-41 em células HEK-293, durante 7 dias. A seguir, as culturas foram analisadas por MCVL e por MET. O HAdV-41 apresentou um ciclo replicativo lento com liberação da progênie viral por mecanismo não lítico. A seguir, com o intuíto de verificar a participação da proteina FC do HAdV-41 nas etapas de entrada nas células HEK-293 e CaCo2, obteve-se os dodecaedros recombinantes (DR) em células High five (base-Ad3, base-Ad3+FC-Ad41, base-Ad3+FL-Ad41, baseRGEHS-Ad3+FCAd41 e base-Ad3+FAd3). Esses dodecaedros foram inoculados em células HEK-293 e CaCo2. Após a análise por MCVL, observou-se que a proteína FC talvez não desempenhe função na entrada do DR nas células estudadas. A seguir, uma alíquota do DR base-Ad3+FC-Ad41 foi digerida com a enzima pepsina e analisada por WB. Notou-se que a FC sofreu proteólise. Acredita-se que essa proteólise seja necessária para o reconhecimento de receptores no trato gastro-intestinal. Esses resultados fornecerão subsídeos para o desenvolvimento de vetores de terapia gênica direcionada para o epitélio intestinal e vetores vacinais administrados por via oral. / Our objective was study the interaction between HAdV-41 and permissive cells. First, it was observed the kinetic of infection between HAdV-41 and HEK-293 cells, for 7 days. Second, the cultures were analyzed by CLSM and by TEM. The HAdV-41 showed a slower replicative cycle with release of viral progeny by non-lytic mechanisms. In order to verify the participation of SF protein of the HAdV-41 during the phases of entry in HEK-293 and CaCo2 cells, we producted recombinant dodecahedrons (DR) in high five cells (base-Ad3, base-Ad3+SF-Ad41, base-Ad3+SF-Ad41, baseRGEHS-Ad3+SFAd41 and base-Ad3+FAd3). These decahedrons were inoculated in HEK-293 and CaCo2 cells. After analysis with CLSM, observed that SF protein may not have a role in dodecahedron entry in the cells studied. Next, recombinant dodecahedrons base-Ad3+SF-Ad41 and base-Ad3 were digested with pepsin and analyzed by WB. We observed proteolysis of the SF. We believe that this proteolysis may be necessary for the recognition of receptors in intestinal cells. The results obtained will be the base for the development of gene-therapy vectors directed to intestinal epithelium, as well as orally administered vaccine vectors.