Papers by Franklin Souza da Silva
Anais do IV International Symposium on Immunobiological e VII Seminário Anual Científico e Tecnológico de Bio-Manguinhos, 2019
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Memórias do Instituto Oswaldo Cruz, 2020
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BioMed Research International, 2020
Leishmaniaspp. proteases have been proposed as virulence factors contributing to adaptive success... more Leishmaniaspp. proteases have been proposed as virulence factors contributing to adaptive success these parasites to the mammalian hosts. Since these enzymes are poorly studied in naturally infected dogs, this work aims to show the differences in metalloprotease and cysteine proteases gene expression in ear edge skin of dogs naturally infected byLeishmania (Leishmania) infantum. A cohort of dogs (n=20) naturally infected byL. (L.) infantumwas clinically classified as asymptomatic, oligosymptomatic, and polysymptomatic and the parasite load range estimated. The analysis of proteases expression by RT-PCR in the ear edge skin was also assessed, suggesting more transcripts of proteases in cDNA samples from polysymptomatic dogs than oligosymptomatic and asymptomatic ones. Metalloprotease RT-PCR assays yielded products (202 bp) in all assessed cDNA dog samples. In contrast, cysteine proteases transcripts (227 bp) had shown to be better detected in cDNA samples of polysymptomatic dogs, com...
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Molecular pharmacology, 2015
Recognition of bacterial lipopolysaccharide (LPS) by innate immune system is mediated by the CD14... more Recognition of bacterial lipopolysaccharide (LPS) by innate immune system is mediated by the CD14/TLR4/MD-2 complex. In the present study, we have investigated the modulatory effect of gedunin, a limonoid from species of the Meliaceae family described as heat shock protein (Hsp)90 inhibitor, on LPS-induced response in immortalized murine macrophages. The pretreatment of wild type (WT) macrophages with gedunin (0.01-100μM, non-cytotoxic concentrations) inhibited LPS (50ng/ml)-induced calcium influx, TNF-α and nitric oxide (NO) production, in a concentration-dependent manner. The selective effect of gedunin on MAL/MyD88- and TRAM/TRIF-dependent signaling pathways was further investigated. The pretreatment of WT, TRIF KO and MAL KO macrophages with gedunin (10μM) significantly inhibited LPS (50ng/ml)-induced TNF-α and IL-6 production, at 6h and 24h, suggesting that gedunin modulates a common event between both signaling pathways. Furthermore, gedunin (10μM) inhibited LPS-induced prosta...
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Affinity Chromatography, 2012
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Current Drug Targets, 2014
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Parasitology, 2011
SUMMARYLeishmaniasis is a vector-borne disease and an important public health issue. Glycosaminog... more SUMMARYLeishmaniasis is a vector-borne disease and an important public health issue. Glycosaminoglycan ligands inLeishmaniaparasites are potential targets for new strategies to control this disease. We report the subcellular distribution of heparin-binding proteins (HBPs) inLeishmania (Viannia) braziliensisand specific biochemical characteristics ofL. (V.) braziliensisHBPs. Promastigotes were fractionated, and flagella and membrane samples were applied to HiTrap Heparin affinity chromatography columns. Heparin-bound fractions from flagella and membrane samples were designated HBP Ffand HBP Mf, respectively. Fraction HBP Ffpresented a higher concentration of HBPs relative to HBP Mf, and SDS-PAGE analyses showed 2 major protein bands in both fractions (65 and 55 kDa). The 65 kDa band showed gelatinolytic activity and was sensitive to inhibition by 1,10-phenanthroline. The localization of HBPs on the promastigote surfaces was confirmed using surface plasmon resonance (SPR) biosensor an...
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Parasites & Vectors, 2012
BackgroundLeishmania (V.) braziliensisis a causative agent of cutaneous leishmaniasis in Brazil. ... more BackgroundLeishmania (V.) braziliensisis a causative agent of cutaneous leishmaniasis in Brazil. During the parasite life cycle, the promastigotes adhere to the gut of sandflies, to avoid being eliminated with the dejection. The Lulo cell line, derived fromLutzomyia longipalpis(Diptera: Psychodidae), is a suitablein vitrostudy model to understand the features of parasite adhesion.Here, we analyze the role of glycosaminoglycans (GAGs) from Lulo cells and proteins from the parasites in this event.MethodsFlagellar (Ff) and membrane (Mf) fractions from promastigotes were obtained by differential centrifugation and the purity of fractions confirmed by western blot assays, using specific antibodies for cellular compartments. Heparin-binding proteins (HBP) were isolated from both fractions using a HiTrap-Heparin column. In addition, binding of promastigotes to Lulo cells or to a heparin-coated surface was assessed by inhibition assays or surface plasmon resonance (SPR) analysis.ResultsThe ...
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BMC Immunology, 2011
BackgroundLeishmaniaparasites have been reported to interfere and even subvert their host immune ... more BackgroundLeishmaniaparasites have been reported to interfere and even subvert their host immune responses to enhance their chances of survival and proliferation. ExperimentalLeishmaniainfection in mice has been widely used in the identification of specific parasite virulence factors involved in the interaction with the host immune system. Cysteine-proteinase B (CPB) is an important virulence factor in parasites from theLeishmania (Leishmania) mexicanacomplex: it inhibits lymphocytes Th1 and/or promotes Th2 responses either through proteolytic activity or through epitopes derived from its COOH-terminal extension. In the present study we analyzed the effects ofLeishmania (Leishmania) amazonensisCPB COOH-terminal extension-derived peptides on cell cultures from murine strains with distinct levels of susceptibility to infection: BALB/c, highly susceptible, and CBA, mildly resistant.ResultsPredicted epitopes, obtained byin silicomapping, displayed the ability to induce cell proliferatio...
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International Journal of Molecular Sciences, 2021
(1) Background: coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome ... more (1) Background: coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been linked to hematological dysfunctions, but there are little experimental data that explain this. Spike (S) and Nucleoprotein (N) proteins have been putatively associated with these dysfunctions. In this work, we analyzed the recruitment of hemoglobin (Hb) and other metabolites (hemin and protoporphyrin IX-PpIX) by SARS-Cov2 proteins using different approaches. (2) Methods: shotgun proteomics (LC–MS/MS) after affinity column adsorption identified hemin-binding SARS-CoV-2 proteins. The parallel synthesis of the peptides technique was used to study the interaction of the receptor bind domain (RBD) and N-terminal domain (NTD) of the S protein with Hb and in silico analysis to identify the binding motifs of the N protein. The plaque assay was used to investigate the inhibitory effect of Hb and the metabolites hemin and PpIX on virus adsorption and replication in Vero cells. (3) Results: the proteomic analysis by LC–MS/MS identified the S, N, M, Nsp3, and Nsp7 as putative hemin-binding proteins. Six short sequences in the RBD and 11 in the NTD of the spike were identified by microarray of peptides to interact with Hb and tree motifs in the N protein by in silico analysis to bind with heme. An inhibitory effect in vitro of Hb, hemin, and PpIX at different levels was observed. Strikingly, free Hb at 1mM suppressed viral replication (99%), and its interaction with SARS-CoV-2 was localized into the RBD region of the spike protein. (4) Conclusions: in this study, we identified that (at least) five proteins (S, N, M, Nsp3, and Nsp7) of SARS-CoV-2 recruit Hb/metabolites. The motifs of the RDB of SARS-CoV-2 spike, which binds Hb, and the sites of the heme bind-N protein were disclosed. In addition, these compounds and PpIX block the virus’s adsorption and replication. Furthermore, we also identified heme-binding motifs and interaction with hemin in N protein and other structural (S and M) and non-structural (Nsp3 and Nsp7) proteins.
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Papers by Franklin Souza da Silva