Angiotensin II-derived constrained peptides with antiplasmodial activity and suppressed vasoconstriction

Angiotensin II (Ang II) is a natural mammalian hormone that has been described to exhibit antiplasmodial activity therefore constituting a promising alternative for the treatment of malaria. Despite its promise, the development of Ang II as an antimalarial is limited by its potent induction of vasoconstriction and its rapid degradation within minutes. Here, we used peptide design to perform targeted chemical modifications to Ang II to generate conformationally restricted (disulfide-crosslinked) peptide derivatives with suppressed vasoconstrictor activity and increased stability. Designed constrained peptides were synthesized chemically and then tested for antiplasmodial activity. Two lead constrained peptides were identified (i.e., peptides 1 and 2), each composed of 10 amino acid residues. These peptides exhibited very promising activity in both our Plasmodium gallinaceum ( > 80%) and Plasmodium falciparum ( > 40%) models, an activity that was equivalent to that of Ang II, and led to complete suppression of vasoconstriction. In addition, peptide 5 exhibited selective activity towards the pre-erythrocytic stage (98% of activity against P. gallinaceum), thus suggesting that it may be possible to design peptides that target specific stages of the malaria life cycle. The Ang II derived stable scaffolds presented here may provide the basis for development of a new generation of peptide-based drugs for the treatment of malaria

Trans-sialidase from Trypanosoma cruzi enhances the adhesion properties and fibronectin-driven migration of thymocytes

In experimental Trypanosoma cruzi infections, severe thymic atrophy leads to release of activated CD4+CD8+ double-positive (DP) T cells to the periphery. In humans, activated DP T cells are found in the blood in association with severe cardiac forms of human chronic Chagas disease. The mechanisms underlying the premature thymocyte release during the chagasic thymic atrophy remain elusive. We tested whether the migratory properties of intrathymic thymocytes are modulated by the parasite trans-sialidase (TS). We found that TS affected the dynamics of thymocytes undergoing intrathymic maturation, and these changes were accompanied by an increase in the number of recent DP thymic emigrants in the peripheral lymphoid organs. We demonstrated that increased percentages of blood DP T cell subsets were associated with augmented antibody titers against TS in chagasic patients with chronic cardiomyopathy. In vitro studies showed that TS was able to activate the MAPK pathway and actin filament mobilization in thymocytes. These effects were correlated with its ability to modulate the adhesion of thymocytes to thymic epithelial cells and their migration toward extracellular matrix. These findings point to effects of TS that could influence the escape of immature thymocytes in Chagas disease.Fil: Nardy, Ana Flávia F.R.. Universidade Federal do Rio de Janeiro; BrasilFil: Silva Filho, Joao Luiz da. Universidade Federal do Rio de Janeiro; BrasilFil: Perez, Ana Rosa. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Instituto de Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Meis, Juliana de. Instituto Oswaldo Cruz; BrasilFil: Farias de Oliveira, Désio Aurélio. Instituto Oswaldo Cruz; BrasilFil: Penha, Luciana. Universidade Federal do Rio de Janeiro; BrasilFil: Oliveira, Isadora de Araújo. Universidade Federal do Rio de Janeiro; BrasilFil: Dias, Wagner B.. Universidade Federal do Rio de Janeiro; BrasilFil: Todeschini, Adriane. Universidade Federal do Rio de Janeiro; BrasilFil: Freire de Lima, Célio Geraldo. Universidade Federal do Rio de Janeiro; BrasilFil: Bellio, Maria. Universidade Federal do Rio de Janeiro; BrasilFil: Caruso Neves, Celso. Universidade Federal do Rio de Janeiro; BrasilFil: Pinheiro, Ana Acácia. Universidade Federal do Rio de Janeiro; BrasilFil: Takiya, Christina Maeda. Universidade Federal do Rio de Janeiro; BrasilFil: Bottasso, Oscar Adelmo. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Instituto de Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Savino, Wilson. Instituto Oswaldo Cruz; BrasilFil: Morrot, Alexandre. Universidade Federal do Rio de Janeiro; Brasi

Lipoxin A4 attenuates endothelial dysfunction during experimental cerebral malaria

Submitted by sandra infurna ([email protected]) on 2016-01-28T13:59:32Z No. of bitstreams: 1 barbara_antunes_etal_IOC_2015.pdf: 906335 bytes, checksum: d9af0df9d57993f82f8cb5ec22e0e37e (MD5)Approved for entry into archive by sandra infurna ([email protected]) on 2016-01-28T14:16:34Z (GMT) No. of bitstreams: 1 barbara_antunes_etal_IOC_2015.pdf: 906335 bytes, checksum: d9af0df9d57993f82f8cb5ec22e0e37e (MD5)Made available in DSpace on 2016-01-28T14:16:34Z (GMT). No. of bitstreams: 1 barbara_antunes_etal_IOC_2015.pdf: 906335 bytes, checksum: d9af0df9d57993f82f8cb5ec22e0e37e (MD5) Previous issue date: 2015Fundação Oswaldo Cruz. Farmanguinhos. Laboratório de Farmacologia Aplicada. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Desenvolvimento Tecnológico em Saúde (CDTS). Instituto Nacional de Ciência e Tecnologia em Inovação para Doenças Negligenciadas (INCT/IDN). Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Farmanguinhos. Laboratório de Farmacologia Aplicada. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Desenvolvimento Tecnológico em Saúde (CDTS). Instituto Nacional de Ciência e Tecnologia em Inovação para Doenças Negligenciadas (INCT/IDN). Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Farmanguinhos. Laboratório de Farmacologia Aplicada. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Desenvolvimento Tecnológico em Saúde (CDTS). Instituto Nacional de Ciência e Tecnologia em Inovação para Doenças Negligenciadas (INCT/IDN). Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Farmanguinhos. Laboratório de Farmacologia Aplicada. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Desenvolvimento Tecnológico em Saúde (CDTS). Instituto Nacional de Ciência e Tecnologia em Inovação para Doenças Negligenciadas (INCT/IDN). Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Farmanguinhos. Laboratório de Farmacologia Aplicada. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Desenvolvimento Tecnológico em Saúde (CDTS). Instituto Nacional de Ciência e Tecnologia em Inovação para Doenças Negligenciadas (INCT/IDN). Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Farmanguinhos. Laboratório de Farmacologia Aplicada. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Desenvolvimento Tecnológico em Saúde (CDTS). Instituto Nacional de Ciência e Tecnologia em Inovação para Doenças Negligenciadas (INCT/IDN). Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Farmanguinhos. Laboratório de Farmacologia Aplicada. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Farmanguinhos. Laboratório de Farmacologia Aplicada. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Desenvolvimento Tecnológico em Saúde (CDTS). Instituto Nacional de Ciência e Tecnologia em Inovação para Doenças Negligenciadas (INCT/IDN). Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Investigação Cardiovascular. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Investigação Cardiovascular. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho (IBCCF). Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho (IBCCF). Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho (IBCCF). Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Investigação Cardiovascular. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Farmanguinhos. Laboratório de Farmacologia Aplicada. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Desenvolvimento Tecnológico em Saúde (CDTS). Instituto Nacional de Ciência e Tecnologia em Inovação para Doenças Negligenciadas (INCT/IDN). Rio de Janeiro, RJ, Brasil.A breakdown of the brain–blood barrier (BBB) due to endothelial dysfunction is a primary feature of cerebral malaria (CM). Lipoxins (LX) are specialized pro-resolving mediators that attenuate endothelial dysfunction in different vascular beds. It has already been shown that LXA4 prolonged Plasmodium berghei-infected mice survival by a mechanism that depends on inhibiting IL-12 production and CD8+IFN-γ+ T cells in brain tissue; however, the effects of this treatment on endothelial dysfunction induced during experimental cerebral malaria (ECM) remains to be elucidated. Herein, we investigate the role of LXA4 on endothelial dysfunction during ECM. The treatment of P. berghei-infected mice with LXA4 prevented BBB breakdown and ameliorated behavioral symptoms but did not modulate TNF-α production. In addition, microcirculation analysis showed that treatment with LXA4 significantly increased functional capillary density in brains of P. berghei-infected C57BL/6 mice. Furthermore, histological analyses of brain sections demonstrated that exogenous LXA4 reduced capillary congestion that was accompanied by reduced ICAM-1 expression in the brain tissue. In agreement, LXA4 treatment of endothelial cells stimulated by Plasmodium berghei (Pb)- or Plasmodium falciparum (Pf)-parasitized red blood cells (RBCs) inhibited ICAM-1 expression. Additionally, LXA4 treatment restored the expression of HO-1 that is reduced during ECM. As well, LXA4 treatment inhibits PbRBC and PfRBC adhesion to endothelial cells that was reversed by the use of an HO-1 inhibitor (ZnPPIX). Our results demonstrate for the first time that LXA4 ameliorates endothelial dysfunction during ECM by modulating ICAM-1 and HO-1 expression in brain tissue

CXCR4 and MIF are required for neutrophil extracellular trap release triggered by Plasmodium-infected erythrocytes.

Neutrophil extracellular traps (NETs) evolved as a unique effector mechanism contributing to resistance against infection that can also promote tissue damage in inflammatory conditions. Malaria infection can trigger NET release, but the mechanisms and consequences of NET formation in this context remain poorly characterized. Here we show that patients suffering from severe malaria had increased amounts of circulating DNA and increased neutrophil elastase (NE) levels in plasma. We used cultured erythrocytes and isolated human neutrophils to show that Plasmodium-infected red blood cells release macrophage migration inhibitory factor (MIF), which in turn caused NET formation by neutrophils in a mechanism dependent on the C-X-C chemokine receptor type 4 (CXCR4). NET production was dependent on histone citrullination by peptidyl arginine deiminase-4 (PAD4) and independent of reactive oxygen species (ROS), myeloperoxidase (MPO) or NE. In vitro, NETs functioned to restrain parasite dissemination in a mechanism dependent on MPO and NE activities. Finally, C57/B6 mice infected with P. berghei ANKA, a well-established model of cerebral malaria, presented high amounts of circulating DNA, while treatment with DNAse increased parasitemia and accelerated mortality, indicating a role for NETs in resistance against Plasmodium infection