Navegando por Palavras-chave "Antimicrobial peptide"
Agora exibindo 1 - 5 de 5
Resultados por página
Opções de Ordenação
- ItemAcesso aberto (Open Access)Characterization of dual effects induced by antimicrobial peptides: Regulated cell death or membrane disruption(Elsevier B.V., 2012-07-01) Paredes-Gamero, Edgar Julian [UNIFESP]; Martins, Marta Natividade Crizol [UNIFESP]; Cappabianco, Fabio Augusto Menocci [UNIFESP]; Ide, Jaime Shinsuke [UNIFESP]; Miranda, Antonio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Background: Some reports describe lysis mechanisms by antimicrobial peptides (AMPs), while others describe the activation of regulated cell death. in this study, we compare the cell death-inducing activities of four beta-hairpin AMPs (gomesin, protegrin, tachyplesin and polyphemusin II) along with their linear analogs in the human erythroleukemia K562 cell line to investigate the relationship between their structure and activity.Methods: K562 cells were exposed to AMPs. Morphological and biochemistry alterations were evaluated using light microscopy, confocal microscopy and flow cytometry.Results: Gomesin and protegrin displayed cytotoxic properties that their linear counterparts did not. Tachyplesin and polyphemusin II and also their linear analogs induced cell death. We were able to distinguish two ways in which these AMPs induced cell death. Lower concentrations of AMPs induced controlled cell death mechanisms. Gomesin, tachyplesin and linear-tachyplesin promoted apoptosis that was characterized by annexin labeling, sensitivity to Z-VAD, and caspase-3 activation, but was also inhibited by necrostatin-1. Gomesin and protegrin induced cell death was dependent on intracellular Ca2+ mechanisms and the participation of free radicals was observed in protegrin induced cell death. Polyphemusin II and its linear analog mainly induced necrosis. Conversely, treatment with higher concentrations of AMPs primarily resulted in cell membrane disruption, but with clearly different patterns of action for each AMP tested.Conclusion: Different actions by beta-hairpin AMPs were observed at low concentrations and at higher concentrations despite the structure similarity.General significance: Controlled intracellular mechanism and direct membrane disruption were clearly distinguished helping to understand the real action of AMPs in mammalian cells. (C) 2012 Elsevier B.V. All rights reserved.
- ItemSomente MetadadadosGomesin acts in the immune system and promotes myeloid differentiation and monocyte/macrophage activation in mouse(Elsevier Science Inc, 2016) Buri, Marcus Vinicius [UNIFESP]; Dias, Carolina Carvalho [UNIFESP]; Barbosa, Christiano Marcello Vaz [UNIFESP]; Nogueira-Pedro, Amanda [UNIFESP]; Ribeiro-Filho, Antonio C.; Miranda, Antonio [UNIFESP]; Paredes-Gamero, Edgar Julian [UNIFESP]Due to the cytotoxic effect of antimicrobial peptides (AMP) against several microorganism and tumor cells has been proposed their association with the immune system. However, just a few reports have shown this relationship. In this study, mice were treated with gomesin, a beta-hairpin AMP that exhibit high cytotoxicity against bacterial and tumor cells. Different effects in the immune system were observed, such as, decrease of CD3(+) in T lymphocytes (Control: 17.7 +/- 1.4%
- ItemSomente MetadadadosHeadgroup specificity for the interaction of the antimicrobial peptide tritrpticin with phospholipid Langmuir monolayers(Elsevier B.V., 2012-12-01) Salay, Luiz C.; Ferreira, Marystela; Oliveira, Osvaldo N.; Nakaie, Clovis R. [UNIFESP]; Schreier, Shirley; Universidade de São Paulo (USP); Universidade Federal de São Carlos (UFSCar); Universidade Federal de São Paulo (UNIFESP)We examined the interaction of the cationic antimicrobial peptide (AMP) tritrpticin (VRRFPWWWPFLRR, TRP3) with Langmuir monolayers of zwitterionic (dipalmitoyl phosphatidylcholine, DPPC, and dipalmitoyl phosphatidylethanolamine, DPPE) and negatively charged phospholipids (dipalmitoyl phosphatidic acid, DPPA, and dipalmitoyl phosphatidylglycerol, DPPG). Both surface pressure and surface potential isotherms became more expanded upon addition of TRP3 (DPPE similar to DPPC << DPPA < DPPG). the stronger interaction with negatively charged phospholipids agrees with data for vesicles and planar lipid bilayers, and with AMPs greater activity against bacterial membranes versus mammalian cell membranes. Considerable expansion of negatively charged monolayers occurred at 10 and 30 mol% TRP3, especially at low surface pressure. Moreover, a difference was observed between PA and PG, demonstrating that the interaction, besides being modulated by electrostatic interactions, displays specificity with regard to headgroup, being more pronounced in the case of PG, present in large quantities in bacterial membranes. in previous studies, it was proposed that the peptide acts by a toroidal pore-like mechanism [1,2]. Considering the evidence from the literature that PG shows a propensity to form a positive curvature as do toroidal pores, the observation of TRP3's preference for the PG headgroup and the dramatic increase in area promoted by this interaction represent further support for the toroidal pore mechanism of action proposed for TRP3. (C) 2012 Elsevier B.V. All rights reserved.
- ItemAcesso aberto (Open Access)Peptide:lipid ratio and membrane surface charge determine the mechanism of action of the antimicrobial peptide BP100. Conformational and functional studies(Elsevier B.V., 2014-07-01) Manzini, Mariana C.; Perez, Katia Regina [UNIFESP]; Riske, Karin Amaral [UNIFESP]; Bozelli, Jose C.; Santos, Talita L.; Silva, Marcia A. da; Saraiva, Greice Kelle Viegas; Politi, Mario J.; Valente, Ana P.; Almeida, Fabio C. L.; Chaimovich, Hernan; Rodrigues, Magali A.; Bemquerer, Marcelo P.; Schreier, Shirley; Cuccovia, Iolanda M.; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP); Universidade Federal do Rio de Janeiro (UFRJ); Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA)The cecropin-melittin hybrid antimicrobial peptide BP100 (H-KKLFKKILKYL-NH2) is selective for Gram-negative bacteria, negatively charged membranes, and weakly hemolytic. We studied BP100 conformational and functional properties upon interaction with large unilamellar vesicles, LUVs, and giant unilamellar vesicles, GUVs, containing variable proportions of phosphatidylcholine (PC) and negatively charged phosphatidylglycerol (PG). CD and NMR spectra showed that upon binding to PG-containing LUVs BP100 acquires a-helical conformation, the helix spanning residues 3-11. Theoretical analyses indicated that the helix is amphipathic and surface-seeking. CD and dynamic light scattering data evinced peptide and/or vesicle aggregation, modulated by peptide: lipid ratio and PG content. BP100 decreased the absolute value of the zeta potential () of LUVs with low PG contents; for higher PG, binding was analyzed as an ion-exchange process. At high salt, BP100-induced LUVS leakage requires higher peptide concentration, indicating that both electrostatic and hydrophobic interactions contribute to peptide binding. While a gradual release took place at low peptide:lipid ratios, instantaneous loss occurred at high ratios, suggesting vesicle disruption. Optical microscopy of GUVs confirmed BP100-promoted disruption of negatively charged membranes. the mechanism of action of BP100 is determined by both peptide:lipid ratio and negatively charged lipid content While gradual release results from membrane perturbation by a small number of peptide molecules giving rise to changes in acyl chain packing, lipid clustering (leading to membrane defects), and/or membrane thinning, membrane disruption results from a sequence of events large-scale peptide and lipid clustering, giving rise to peptide-lipid patches that eventually would leave the membrane in a carpet-like mechanism. (C) 2014 Elsevier B.V. All rights reserved.
- ItemSomente MetadadadosPeptidomics of Acanthoscurria gomesiana spider venom reveals new toxins with potential antimicrobial activity(Elsevier Science Bv, 2017) Abreu, Thiago F. [UNIFESP]; Sumitomo, Bianca N. [UNIFESP]; Nishiyama, Milton Y., Jr.; Oliveira, Ursula C.; Souza, Gustavo H. M. F.; Kitano, Eduardo S.; Zelanis, Andre [UNIFESP]; Serrano, Solange M. T.; Junqueira-de-Azevedo, Inacio; Silva, Pedro I., Jr.; Tashima, Alexandre K. [UNIFESP]Acanthoscurria gomesiana is a Brazilian spider from the Theraphosidae family inhabiting regions of Southeastern Brazil. Potent antimicrobial peptides as gomesin and acanthoscurrin have been discovered from the spider hemolymph in previous works. Spider venoms are also recognized as sources of biologically active peptides, however the venom peptidome of A. gomesiana remained unexplored to date. In this work, a MS-based workflow was applied to the investigation of the spider venom peptidome. Data-independent and data-dependent LC-MS/MS acquisitions of intact peptides and of peptides submitted to multiple enzyme digestions, followed by automated chromatographic alignment, de novo analysis, database and homology searches with manual validations showed that the venom is composed by <165 features, with masses ranging from 0.4-15.8 kDa. From digestions, 135 peptides were identified from 17 proteins, including three new mature peptides: U1-TRTX-Agm1a, U1-TRTX-Agm2a and Ul-TRTX-Agm3a, containing 3, 4 and 3 disulfide bonds, respectively. The toxins U1-TRTX-Agm1a differed by only one amino acid from Ul-TRTX-Apl a from A. paulensis and U1-TRTX-Agm2a was derived from the genicutoxin-D1 precursor from A. geniculata. These toxins have potential applications as antimicrobial agents, as the peptide fraction of A. gomesiana showed activity against Escherichia coli, Enterobacter cloacae and Candida albicans strains. MS data are available via ProteomeXchange Consortium with identifier PXD003884. Biological significance: Biological fluids of the Acanthoscurria gomesiana spider are sources of active molecules, as is the case of antimicrobial peptides and acylpolyamines found in the hemolymphs. The venom is also a potential source of toxins with pharmacological and biotechnological applications. However, to our knowledge no A. gomesiana venom toxin structure has been determined to date. Using a combination of high resolution mass spectrometry, transcriptomics and bioinformatics, we employed a workflow to fully sequence, determine the number of disulfide bonds of mature peptides and we found new potential antimicrobial peptides. This workflow is suitable for complete peptide toxin sequencing when handling limited amount of venom samples and can accelerate the discovery of peptides with potential biotechnological applications. (C) 2016 Elsevier B.V. All rights reserved.