Navegando por Palavras-chave "Snake toxin"

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    Biophysical and biological properties of small linear peptides derived from crotamine, a cationic antimicrobial/antitumoral toxin with cell penetrating and cargo delivery abilities
    (Elsevier Science Bv, 2017) Dal Mas, C. [UNIFESP]; Pinheiro, D. A. [UNIFESP]; Campeiro, J. D. [UNIFESP]; Mattei, B. [UNIFESP]; Oliveira, V. [UNIFESP]; Oliveira, E. B.; Miranda, A. [UNIFESP]; Perez, K. R. [UNIFESP]; Hayashi, M. A. F. [UNIFESP]
    Crotamine is a natural polypeptide from snake venom which delivers nucleic acid molecules into cells, besides having pronounced affinity for negatively charged membranes and antifungal activity. We previously demonstrated that crotamine derived short linear peptides were not very effective as antifungal, although the non structured recombinant crotamine was overridingly more potent compared to the native structured crotamine. Aiming to identify the features necessary for the antifungal activity of crotamine, two linear short peptides, each comprising half of the total positively charged amino acid residues of the full-length crotamine were evaluated here to show that these linear peptides keep the ability to interact with lipid membrane model systems with different phospholipid compositions, even after forming complexes with DNA. Interestingly, the presence of cysteine residues in the structure of these linear peptides highly influenced the antifungal activity, which was not associated to the lipid membrane lytic activity. In addition to the importance of the positive charges, the crucial role of cysteine residues was noticed for these linear analogs of crotamine, although the tridimensional structure and lipid membrane lytic activity observed only for native crotamine was not essential for the antifungal activity. As these peptides still keep the ability to form complexes with DNA molecules with no prejudice to their ability to bind to lipid membranes, they may be potentially advantageous as membrane translocation vector, as they do not show lipid membrane lytic activity and may harbor or not antifungal activity, by keeping or not the semi-essential amino acid cysteine in their sequence.
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    Design and characterization of crotamine-functionalized gold nanoparticles
    (Elsevier Science Bv, 2018) Karpel, Richard L.; Liberato, Michelle da Silva; Campeiro, Joana Darc [UNIFESP]; Bergeon, Lorna; Szychowski, Brian; Butler, Andrew; Marino, Giovanni; Cusic, Joelle F.; Oliveira, Lilian Caroline Goncalves de [UNIFESP]; Oliveira, Eduardo B.; Farias, Marcelo Alexandre de; Portugal, Rodrigo Villares; Alves, Wendel Andrade; Daniel, Marie-Christine; Hayashi, Mirian Akemi Furuie [UNIFESP]
    This paper describes the development of a facile and environmentally friendly strategy for supporting crotamine on gold nanoparticles (GNPs). Our approach was based on the covalent binding interaction between the cell penetrating peptide crotamine, which is a snake venom polypeptide with preference to penetrate dividing cells, and a polyethylene glycol (PEG) ligand, which is a nontoxic, water-soluble and easily obtainable commercial polymer. Crotamine was derivatized with ortho-pyridyldisulfide-polyethyleneglycol-N-hydroxysuccinimide (OPSS-PEG-SVA) cross-linker to produce OPSS-PEG-crotamine as the surface modifier of GNP. OPSS-PEG-SVA can serve not only as a surface modifier, but also as a stabilizing agent for GNPs. The successful PEGylation of the nanoparticles was demonstrated using different physicochemical techniques, while the grafting densities of the PEG ligands and crotamine on the surface of the nanoparticles were estimated using a combination of electron microscopy and mass spectrometry analysis. In vitro assays confirmed the internalization of these GNPs, into living HeLa cells. The results described herein suggest that our approach may serve as a simple platform for the synthesis Of GNPs decorated with crotamine with well-defined morphologies and uniform dispersion, opening new roads for crotamine biomedical applications. (C) 2017 Elsevier B.V. All rights reserved.
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    Enzyme specificity and effects of gyroxin, a serine protease from the venom of the South American rattlesnake Crotalus durissus terrificus, on protease-activated receptors
    (Elsevier B.V., 2014-03-01) Yonamine, Camila M. [UNIFESP]; Kondo, Marcia Y. [UNIFESP]; Nering, Marcela B. [UNIFESP]; Gouvea, Iuri E. [UNIFESP]; Okamoto, Debora [UNIFESP]; Andrade, Douglas [UNIFESP]; Silva, Jose Alberto A. da; Prieto da Silva, Alvaro R. B.; Yamane, Tetsuo; Juliano, Maria A. [UNIFESP]; Juliano, Luiz [UNIFESP]; Lapa, Antonio J. [UNIFESP]; Hayashi, Mirian A. F. [UNIFESP]; Lima-Landman, Maria Teresa R. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); IPEN; Inst Butantan; Univ Estado Amazonas
    Gyroxin is a serine protease displaying a thrombin-like activity found in the venom of the South American rattlesnake Crotalus durissus terrificus. Typically, intravenous injection of purified gyroxin induces a barrel rotation syndrome in mice. the serine protease thrombin activates platelets aggregation by cleaving and releasing a tethered N-terminus peptide from the G-protein-coupled receptors, known as protease-activated receptors (PARs). Gyroxin also presents pro-coagulant activity suggested to be dependent of PARs activation. in the present work, the effects of these serine proteases, namely gyroxin and thrombin, on PARs were comparatively studied by characterizing the hydrolytic specificity and kinetics using PARs-mimetic FRET peptides. We show for the first time that the short (sh) and long (lg) peptides mimetizing the PAR-1, -2, -3, and -4 activation sites are all hydrolyzed by gyroxin exclusively after the Arg residues. Thrombin also hydrolyzes PAR-1 and -4 after the Arg residue, but hydrolyzes sh and lg PAR-3 after the Lys residue. the k(cat)/K-M values determined for gyroxin using sh and lg PAR-4 mimetic peptides were at least 2150 and 400 times smaller than those determined for thrombin, respectively. for the sh and lg PAR-2 mimetic peptides the k(cat)/K-M values determined for gyroxin were at least 6500 and 2919 times smaller than those determined for trypsin, respectively. the k(cat)/K-M values for gyroxin using the PAR-1 and -3 mimetic peptides could not be determined due to the extreme low hydrolysis velocity. Moreover, the functional studies of the effects of gyroxin on PARs were conducted in living cells using cultured astrocytes, which express all PARs. Despite the ability to cleavage the PAR-I, -2, -3, and -4 peptides, gyroxin was unable to activate the PARs expressed in astrocytes as determined by evaluating the cytosolic calcium mobilization. On the other hand, we also showed that gyroxin is able to interfere with the activation of PAR-1 by thrombin or by synthetic PAR-1 agonist in cultured astrocytes. Taken together, the data presented here allow us showing that gyroxin cleaves PARs-mimetic peptides slowly and it does not induce activation of PARs in astrocytes. Although gyroxin does not mobilize calcium it was shown to interfere with PARs activation by thrombin and PAR-1 agonist. the determination of gyroxin enzymatic specificity and kinetics on PAR-1, -2, -3, and -4 will potentially help to fill the gap in the knowledge in this field, as the PARs are still believed to have a key role for the gyroxin biological effects. (C) 2013 Elsevier B.V. All rights reserved.
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    Oral treatment with a rattlesnake native polypeptide crotamine efficiently inhibits the tumor growth with no potential toxicity for the host animal and with suggestive positive effects on animal metabolic profile
    (Springer Wien, 2018) Campeiro, Joana D. [UNIFESP]; Marinovic, Marcelo P. [UNIFESP]; Carapeto, Fernando Cintra [UNIFESP]; Dal Mas, Caroline [UNIFESP]; Monte, Gabriela Guilherme [UNIFESP]; Porta, Lucas Carvalho [UNIFESP]; Nering, Marcela B. [UNIFESP]; Oliveira, Eduardo B.; Hayashi, Mirian A. F. [UNIFESP]
    The efficacy of crotamine as antitumoral was first demonstrated by daily intraperitoneal (IP) injections of low doses of this toxin in an animal model bearing melanoma tumors. Significant inhibition of tumor growth and increased lifespan of mice bearing tumor was also noticed after 21 consecutive days of this daily IP administration of crotamine. However, due to the limited acceptance of treatments by IP route in clinical conditions, herein, we evaluated the antitumor effect of this native polypeptide employing the oral route. The efficacy of crotamine in inhibiting the melanoma growth in vivo, even after passing through the gastrointestinal tract of the animal, was confirmed here. In addition, biochemical biomarkers and also histopathological analysis showed both the absence of any potential toxic effects in tissues or organs of the animal in which the highest accumulation of crotamine is expected. Interestingly, a reduction of weight gain was observed mainly in animals with tumor treated with crotamine by IP route, but not by oral administration. Albeit, oral administered crotamine was able to significantly decrease the body weight gain of healthy animals without tumor. Taking advantage of this same experimental animal models receiving crotamine by oral route, it was possible to show metabolic changes as the increased capacity of glucose clearance, which was accompanied by a reduction of the total cholesterol, and by increased high-density lipoprotein levels, both observed mainly in the absence of tumor. Triglycerides and low-density lipoprotein were also significantly decreased, but only in the absence of tumor. Taken together, these data suggest a clear trend for metabolic positive effects and mischaracterize unhealthy condition of animals, with or without tumors, treated with crotamine for 21 days. In addition, this study confirmed the efficacy of crotamine administered by oral route as antitumor agent, which besides the additional advantage of administration convenience and decreased risk of toxic effects, allowed the serendipitous observation of several positive metabolic effects on treated animals.