ERIKA GRACIELLE PINTO

(Fonte: Lattes)
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13
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Agora exibindo 1 - 4 de 4
  • article 9 Citação(ões) na Scopus
    Antileishmanial and antitrypanosomal activity of the cutaneous secretion of Siphonops annulatus
    (2014) PINTO, Erika Gracielle; ANTONIAZZI, Marta Maria; JARED, Carlos; TEMPONE, Andre Gustavo
    Background: Among the tropical parasitic diseases, those caused by protozoans are considered a challenge to public health, being represented by leishmaniasis and Chagas disease. In view of the low effectiveness and toxicity of the current therapy, animal venoms such as amphibian secretions have been used as a promising source of new drug prototypes. The present work aimed to achieve bioguided fractionation of metabolites present in a cutaneous secretion of the caecilian Siphonops annulatus (Amphibia: Gymnophiona: Siphonopidae) with antileishmanial and antitrypanosomal activity. Methods: Through liquid-liquid partition and chromatographic techniques, the secretion was fractionated using bioguided assays. The 50% inhibitory concentration (IC50) of the main fraction (SaFr1) was studied against Leishmania (L.) infantum promastigotes and intracellular amastigotes, trypomastigotes of Trypanosoma cruzi and mammalian cells; viability was detected by the colorimetric MTT assay. By using a spectrofluorimetric assay with the probe SYTOX (R) Green and transmission electron microscopy (TEM), we also investigated the potential damage caused by SaFr1 in the plasma membrane and mitochondria of Leishmania. Results: The bioguided assay enabled isolation of a highly purified fraction (SaFr1) with an IC50 of 0.065 mu g/mL against promastigotes and 2.75 mu g/mL against trypomastigotes. Due to its high toxicity to peritoneal macrophages, SaFr1 showed no selectivity towards the intracellular forms of Leishmania. Ultrastructural studies with Leishmania demonstrated severe mitochondrial damage and the formation of large cytoplasmic vacuoles, leading to the parasite's death within a few hours. Nevertheless, it caused no alteration in the plasma membrane permeability as detected by the fluorescent probe and TEM. Conclusions: The present study demonstrated for the first time the antiparasitic activity of the skin secretion of the caecilian S. annulatus against Leishmania and T. cruzi, confirming that skin secretions of these amphibians, similarly to those of anurans and salamanders, are also potential tools for the development of new drug candidates against neglected diseases.
  • article 26 Citação(ões) na Scopus
    Lethal action of the nitrothiazolyl-salicylamide derivative nitazoxanide via induction of oxidative stress in Leishmania (L.) infantum
    (2013) MESQUITA, Juliana Tonini; PINTO, Erika Gracielle; TANIWAKI, Noemi Nosomi; GALISTEO JR., Andres Jimenez; TEMPONE, Andre Gustavo
    Studying the cellular death pathways in Leishmania is an important aspect of discovering new antileishmanials. While using a drug repositioning approach, the lethal action of the nitrothiazolyl-salicylamide derivative nitazoxanide (NTZ) was investigated against Leishmania (L.) infantum. The in vitro antileishmanial activity and cytotoxicity were assessed using both parasite stages and mammalian NCTC cells, respectively. The lethal action of NTZ was investigated by detecting the phosphatidylserine (PS) exposure, reactive oxygen species (ROS) regulation, plasma membrane permeability, mitochondrial membrane potential and ultrastructural modifications by transmission electron microscopy. NTZ's activity against L. infantum was confirmed, producing IC50 values of 42.71 mu g/mL against promastigotes and 6.78 mu g/mL against intracellular amastigotes. NTZ rapidly altered the cellular metabolism of promastigotes by depolarising the mitochondrial membrane and up-regulating the reactive oxygen species (ROS). In addition, the flow cytometry data revealed an intense and time-dependent exposure of PS in promastigotes. When using SYTOX (R) Green as a fluorescent probe, NTZ demonstrated no interference in plasma membrane permeability. The ultrastructural alterations in promastigotes were time-dependent and caused chromatin condensation, plasma membrane blebbing and mitochondrial swelling. These data suggest that NTZ induced oxidative stress in L. (L.) infantum and might be a useful compound for investigating new therapeutic targets.
  • article 24 Citação(ões) na Scopus
    Melittin induces in vitro death of Leishmania (Leishmania) infantum by triggering the cellular innate immune response
    (2016) PEREIRA, Andreia Vieira; BARROS, Gustavo de; PINTO, Erika Gracielle; TEMPONE, Andre Gustavo; ORSI, Ricardo de Oliveira; SANTOS, Lucilene Delazari dos; CALVI, Sueli; FERREIRA JR., Rui Seabra; PIMENTA, Daniel Carvalho; BARRAVIERA, Benedito
    Background: Apis mellifera venom, which has already been recommended as an alternative anti-inflammatory treatment, may be also considered an important source of candidate molecules for biotechnological and biomedical uses, such as the treatment of parasitic diseases. Methods: Africanized honeybee venom from Apis mellifera was fractionated by RP-C18-HPLC and the obtained melittin was incubated with promastigotes and intracellular amastigotes of Leishmania (L.) infantum. Cytotoxicity to mice peritoneal macrophages was evaluated through mitochondrial oxidative activity. The production of anti-and pro-inflammatory cytokines, NO and H2O2 by macrophages was determined. Results: Promastigotes and intracellular amastigotes were susceptible to melittin (IC50 28.3 mu g.mL(-1) and 1.4 mu g.mL(-1), respectively), but also showed mammalian cell cytotoxicity with an IC50 value of 5.7 mu g.mL(-1). Uninfected macrophages treated with melittin increased the production of IL-10, TNF-alpha, NO and H2O2. Infected melittin-treated macrophages increased IL-12 production, but decreased the levels of IL-10, TNF-alpha, NO and H2O2. Conclusions: The results showed that melittin acts in vitro against promastigotes and intracellular amastigotes of Leishmania (L.) infantum. Furthermore, they can act indirectly on intracellular amastigotes through a macrophage immunomodulatory effect.
  • article 40 Citação(ões) na Scopus
    Antimicrobial peptides isolated from Phyllomedusa nordestina (Amphibia) alter the permeability of plasma membrane of Leishmania and Trypanosoma cruzi
    (2013) PINTO, Erika Gracielle; PIMENTA, Daniel C.; ANTONIAZZI, Marta Maria; JARED, Carlos; TEMPONE, Andre Gustavo
    Nature has provided inspiration for Drug Discovery studies and amphibian secretions have been used as a promising source of effective peptides which could be explored as novel drug prototypes for neglected parasitic diseases as Leishmaniasis and Chagas disease. In this study, we isolated four antimicrobial peptides (AMPS) from Phyllomedusa nordestina secretion, and studied their effectiveness against Leishmania (L) infantum and Trypanosoma cruzi. The antiparasitic fractions were characterized by mass spectrometry and Edman degradation, leading to the identification of dermaseptins 1 and 4 and phylloseptins 7 and 8. T. cruzi trypomastigotes were susceptible to peptides, showing IC50 values in the range concentration of 0.25-0.68 mu M. Leishmania (L.) infantum showed susceptibility to phylloseptin 7, presenting an IC50 value of 10 mu M. Except for phylloseptin 7 which moderate showed cytotoxicity (IC50 (=) 34 mu M), the peptides induced no cellular damage to mammalian cells. The lack of rnitochondrial oxidative activity of parasites detected by the MTT assay, suggested that peptides were leishmanicidal and trypanocidal. By using the fluorescent probe SYTOX (R) Green, dermaseptins 1 and 4 and phylloseptins 7 and 8 showed time-dependent plasma membrane permeabilization of T. cruzi; phylloseptin 7 also showed a similar effect in Leishmania parasites. The present study demonstrates for the first time that AMPs target the plasma membrane of Leishmania and T. cruzi, leading to cellular death. Considering the potential of amphibian peptides against protozoan parasites and the reduced mammalian toxicity, they may contribute as scaffolds for drug design studies.