Browsing by Author "Nagem, Ronaldo Alves Pinto"

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    Effect of ionizing radiation exposure on Trypanosoma cruzi ubiquitin-proteasome system.
    (2017) Cerqueira, Paula Gonçalves; Silva, Danielle Gomes Passos; Rocha, João Pedro Vieira da; Mendes, Isabela Cecilia; Oliveira, Karla Andrade de; Oliveira, Camila Franco Batista de; Vilela, Liza Figueiredo Felicori; Nagem, Ronaldo Alves Pinto; Cardoso, Josiane; Nardelli, Sheila Cristina; Krieger, Marco Aurélio; Franco, Glória Regina; Macedo, Andréa Mara; Pena, Sérgio Danilo Junho; Schenkman, Sérgio; Gomes, Dawidson Assis; Cota, Renata Guerra de Sá; Machado, Carlos Renato
    tIn recent years, proteasome involvement in the damage response induced by ionizing radiation (IR)became evident. However, whether proteasome plays a direct or indirect role in IR-induced damageresponse still unclear. Trypanosoma cruzi is a human parasite capable of remarkable high tolerance toIR, suggesting a highly efficient damage response system. Here, we investigate the role of T. cruzi pro-teasome in the damage response induced by IR. We exposed epimastigotes to high doses of gamma rayand we analyzed the expression and subcellular localization of several components of the ubiquitin-proteasome system. We show that proteasome inhibition increases IR-induced cell growth arrest andproteasome-mediated proteolysis is altered after parasite exposure. We observed nuclear accumulationof 19S and 20S proteasome subunits in response to IR treatments. Intriguingly, the dynamic of 19S par-ticle nuclear accumulation was more similar to the dynamic observed for Rad51 nuclear translocationthan the observed for 20S. In the other hand, 20S increase and nuclear translocation could be relatedwith an increase of its regulator PA26 and high levels of proteasome-mediated proteolysis in vitro. Theintersection between the opposed peaks of 19S and 20S protein levels was marked by nuclear accumu-lation of both 20S and 19S together with Ubiquitin, suggesting a role of ubiquitin-proteasome system inthe nuclear protein turnover at the time. Our results revealed the importance of proteasome-mediatedproteolysis in T. cruzi IR-induced damage response suggesting that proteasome is also involved in T. cruziIR tolerance. Moreover, our data support the possible direct/signaling role of 19S in DNA damage repair.Based on these results, we speculate that spatial and temporal differences between the 19S particle and20S proteasome controls proteasome multiple roles in IR damage response.
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    Epitope mapping of the HSP83.1 protein of Leishmania braziliensis discloses novel targets for immunodiagnosis of tegumentary and visceral clinical forms of leishmaniasis.
    (2014) Souza, Daniel Menezes; Mendes, Tiago Antônio de Oliveira; Gomes, Matheus de Souza; Cunha, João Luís Reis; Nagem, Ronaldo Alves Pinto; Carneiro, Cláudia Martins; Coelho, Eduardo Antônio Ferraz; Galvão, Lúcia Maria da Cunha; Fujiwara, Ricardo Toshio; Bartholomeu, Daniella Castanheira
    Gold standard serological diagnostic methods focus on antigens that elicit a strong humoral immune response that is specific to a certain pathogen. In this study, we used bioinformatics approaches to identify linear B-cell epitopes that are conserved among Leishmania species but are divergent from the host species Homo sapiens and Canis familiaris and from Trypanosoma cruzi, the parasite that causes Chagas disease, to select potential targets for the immunodiagnosis of leishmaniasis. Using these criteria, we selected heat shock protein 83.1 of Leishmania braziliensis for this study. We predicted three linear B-cell epitopes in its sequence. These peptides and the recombinant heat shock protein 83.1 (rHSP83.1) were tested in enzyme-linked immunosorbent assays (ELISAs) against serum samples from patients with tegumentary leishmaniasis (TL) and visceral leishmaniasis (VL) and from dogs infected with Leishmania infantum (canine VL [CVL]). Our data show that rHSP83.1 is a promising target in the diagnosis of TL. We also identified specific epitopes derived from HSP83.1 that can be used in the diagnosis of human TL (peptide 3), both human and canine VL (peptides 1 and 3), and all TL, VL, and CVL clinical manifestations (peptide 3). Receiver operating characteristic (ROC) curves confirmed the superior performance of rHSP83.1 and peptides 1 and 3 compared to that of the soluble L. braziliensis antigen and the reference test kit for the diagnosis of CVL in Brazil (EIE-LVC kit; Bio-Manguinhos, Fiocruz). Our study thus provides proof-of-principle evidence of the feasibility of using bioinformatics to identify novel targets for the immunodiagnosis of parasitic diseases using proteins that are highly conserved throughout evolution.
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    Evaluation of three recombinant proteins for the development of ELISA and immunochromatographic tests for visceral leishmaniasis serodiagnosis.
    (2019) Santos, Anna Raquel Ribeiro dos; Serufo, Ângela Vieira; Figueiredo, Maria Marta; Godoi, Lara Carvalho; Vitório, Jéssica Gardone; Marcelino, Andreza Pain; Avelar, Daniel Moreira de; Rodrigues, Fernandes Tenório Gomes; Coelho, George Luiz Lins Machado; Medeiros, Fernanda Alvarenga Cardoso; Jeronimo, Selma Maria Bezerra; Oliveira, Edward José de; Nascimento, Frederico Crepaldi; Teixeira, Santuza Maria Ribeiro; Gazzinelli, Ricardo Tostes; Nagem, Ronaldo Alves Pinto; Fernandes, Ana Paula
    BACKGROUND Visceral Leishmaniasis (VL) is an infectious disease that is a significant cause of death among infants aged under 1 year and the elderly in Brazil. Serodiagnosis is a mainstay of VL elimination programs; however, it has significant limitations due to low accuracy. OBJECTIVE This study aimed to evaluate three recombinant Leishmania infantum proteins (rFc, rC9, and rA2) selected from previous proteomics and genomics analyses to develop enzyme-linked immunosorbent assay (ELISA) and immunochromatographic tests (ICT) for the serodiagnosis of human VL (HVL) and canine VL (CVL). METHODS A total of 186 human (70 L. infantum-infected symptomatic, 20 other disease-infected, and 96 healthy) and 185 canine (82 L. infantum-infected symptomatic, 27 L. infantum-infected asymptomatic, and 76 healthy) sera samples were used for antibody detection. FINDINGS Of the three proteins, rA2 (91.5% sensitivity and 87% specificity) and rC9 (95.7% sensitivity and 87.5% specificity) displayed the best performance in ELISA-HVL and ELISA-CVL, respectively. ICT-rA2 also displayed the best performance for HVL diagnosis (92.3% sensitivity and 88.0% specificity) and had high concordance with immunofluorescence antibody tests (IFAT), ELISA-rK39, IT-LEISH®, and ELISAEXT. ICT-rFc, ICT-rC9, and ICT-rA2 had sensitivities of 88.6%, 86.5%, and 87.0%, respectively, with specificity values of 84.0%, 92.0%, and 100%, respectively for CVL diagnosis. MAIN CONCLUSIONS The three antigens selected by us are promising candidates for VL diagnosis regardless of the test format, although the antigen combinations and test parameters may warrant further optimisation.
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    Phoneutria toxin PnTx3-5 inhibits TRPV1 channel with antinociceptive action in an orofacial pain model.
    (2020) Pereira, Elizete Maria Rita; Souza, Jéssica Mabelle; Carobin, Natália Virtude; Silva, Juliana Figueira da; Astoni, Duana Carvalho dos Santos; Silva Júnior, Cláudio Antônio da; Binda, Nancy Scardua; Borges, Marcia Helena; Nagem, Ronaldo Alves Pinto; Kushmerick, Christopher; Ferreira, Juliano; Castro Junior, Célio José de; Ribeiro, Fabiola Mara; Gomez, Marcus Vinicius
    Capsaicin, an agonist of TRPV1, evokes intracellular [Ca2+] transients and glutamate release from perfused trigeminal ganglion. The spider toxin PnTx3-5, native or recombinant is more potent than the selective TRPV1 blocker SB-366791 with IC50 of 47 ± 0.18 nM, 45 ± 1.18 nM and 390 ± 5.1 nM in the same experimental conditions. PnTx3-5 is thus more potent than the selective TRPV1 blocker SB-366791. PnTx3-5 (40 nM) and SB-366791 (3 μM) also inhibited the capsaicin-induced increase in intracellular Ca2+ in HEK293 cells transfected with TRPV1 by 75 ± 16% and 84 ± 3.2%, respectively. In HEK293 cells transfected with TRPA1, cinnamaldehyde (30 μM) generated an increase in intracellular Ca2+ that was blocked by the TRPA1 antagonist HC-030031 (10 μM, 89% inhibition), but not by PnTx3-5 (40 nM), indicating selectivity of the toxin for TRPV1. In whole-cell patch-clamp experiments on HEK293 cells transfected with TRPV1, capsaicin (10 μM) generated inward currents that were blocked by SB-366791 and by both native and recombinant PnTx3-5 by 47 ± 1.4%; 54 ± 7.8% and 56 ± 9.0%, respectively. Intradermal injection of capsaicin into the rat left vibrissa induced nociceptive behavior that was blocked by pre-injection with either SB-366791 (3 nmol/site i.d., 83.3 ± 7.2% inhibition) or PnTx3-5 (100 fmol/site, 89 ± 8.4% inhibition). We conclude that both native and recombinant PnTx3-5 are potent TRPV1 receptor antagonists with antinociceptive action on pain behavior evoked by capsaicin.