Fish Oil and Inflammation: A Perspective on the Challenges of Evaluating Efficacy in <em>Trypanosoma cruzi</em> Infection

Parasitic diseases constitute a big problem of ill health in both the tropics and subtropics as well as in more temperate climates and have been targeted by the Centers for Disease Control and Prevention (CDC) as priorities for public health in the USA. Parasitic infections can be caused by three types of organisms: protozoa, helminths and ectoparasites. They subsist on the host’s nutrients at the host’s expense. Effectively combating infections caused by parasites is essential for the survival of the organism. In this effort, cells and molecules of the immune system are susceptible to the modulating influence of fatty acids. The primary purpose of this chapter is to present a critical review of the multiple effects of fish-oil on Trypanosoma infection

Vesículas extracelulares secretadas por Trypanosoma cruzi e a relação com ácidos graxos poli-insaturados na modulação da infecção experimental

Submitted by Repositório Arca ([email protected]) on 2019-03-07T12:08:30Z No. of bitstreams: 1 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5)Approved for entry into archive by Manoel Barata ([email protected]) on 2019-04-29T19:52:19Z (GMT) No. of bitstreams: 2 Tese_Maria_Lovo.pdf: 27943326 bytes, checksum: 52e66ae673d354224df11c69622d2aab (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5)Made available in DSpace on 2019-04-29T19:52:19Z (GMT). No. of bitstreams: 2 Tese_Maria_Lovo.pdf: 27943326 bytes, checksum: 52e66ae673d354224df11c69622d2aab (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2018Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.Durante a infecção por Trypanosoma cruzi a resposta imunológica é importante para o controle do parasitismo e sobrevida do hospedeiro. Contudo, o parasito apresenta mecanismos de evasão que garantem sua persistência e o desenvolvimento da fase crônica da infecção. As vesículas extracelulares de T. cruzi Y (EVs Y) participam da comunicação intercelular ao carrearem moléculas funcionais que sinalizam para células do hospedeiro podendo modular a resposta imunológica a favor do parasito. A suplementação de dietas com ácidos graxos poli-insaturados (PUFAs) n-3 tem sido associada com redução da inflamação e modulação da resistência às infecções. Nosso grupo mostrou recentemente que a suplementação oral com óleo de peixe é benéfica para o hospedeiro durante a fase aguda da infecção por T. cruzi. O objetivo da tese foi avaliar os efeitos imunopatológicos das EVs Y, assim como a sua associação à ação imunomoduladora dos PUFAs na patogênese da doença de Chagas experimental. Camundongos C57BL/6 que receberam o inóculo de EV Y previamente à infecção por T. cruzi apresentaram maior parasitemia, maior parasitismo cardíaco, diminuição dos níveis de óxido nítrico (NO) plasmático e daquele produzido por células esplênicas. As EVs Y também modularam a produção de citocinas pró-inflamatórias, com redução do TNF-α plasmático e menor produção de TNF-α e de IL-6 por células esplênicas obtidas de animais infectados. Em ensaios in vitro utilizando macrófagos, o estímulo com EVs Y previamente à infecção por T. cruzi aumentou a internalização de amastigotas assim como a liberação de formas tripomastigotas. Neste mesmo cenário, as EVs Y induziram a formação de corpos lipídicos e a produção de prostaglandina E2 em macrófagos, mesmo na ausência do T. cruzi, e diminuíram a produção de NO frente ao estímulo com LPS. A suplementação oral dos animais com óleo de milho (CO) ou óleo de peixe (FO) impediu o aumento da parasitemia em animais previamente tratados com EVs Y. Além disso, a estimulação com EVs Y não reduziu a produção de NO pelos esplenócitos dos animais suplementados com FO, indicando que a ingestão de FO rico em PUFAs n-3 impede os efeitos moduladores das EVs Y sobre a resposta dos animais à infecção. In vitro, o tratamento de macrófagos com ácido araquidônico associado às EVs Y aumentou a internalização de parasitos nessas células, enquanto o tratamento com ácido eicosapentaenóico associado às EVs Y diminuiu a internalização de parasitos. Macrófagos tratados com ácido linoleico ou oleico tiveram maior liberação de tripomastigotas, que foi potencializada pela associação desses ácidos graxos com EVs Y. Já nos macrófagos tratados com ácidos araquidônico, eicosapentaenóico ou docosahexaenóico não houve liberação de tripomastigotas, mesmo quando associados às EVs Y. Esses resultados sugerem que as EVs Y modulam a resposta do hospedeiro a favor do parasito enquanto os PUFAs n-3 interferem na modulação exercida pelas EVs Y.During the infection by Trypanosoma cruzi the immune response is important for the for the control of parasitism and host survival. However, the parasite presents evasion mechanisms that work in favor of its chronic persistence. T. cruzi extracellular vesicles (EVs Y) has a role in intracellular communication by carrying functional molecules that signal to host cells and can modulate the immune response in favor of the parasite. The supplementation of diet with polyunsaturated fatty acids (PUFAs) n-3 has been associated with reduced inflammation and modulation of resistance to infections. Recently we showed that fish oil supplementation benefits the host during the acute phase of T. cruzi infection. Therefore, the objective of this work was to evaluate the immunopathological effects of EVs Y, as well as its association with the immunomodulatory action of PUFAs in the pathogenesis of experimental Chagas' disease. C57BL/6 mice that received the inoculum of EV Y prior to T. cruzi infection showed higher parasitemia, greater cardiac parasitism, decreased levels of plasma nitric oxide (NO) and that produced by splenic cells. The EVs Y also modulated the production of pro-inflammatory cytokines, with reduction of plasma TNF-α and lower production of TNF-α and IL-6 by spleen cells from infected animals. In vitro assays using macrophages, the stimulation with EVs Y prior to T. cruzi infection increased the parasites internalization rate as well as the release of trypomastigote forms by these cells. In this same scenario, EVs Y induced lipid bodies formation and prostaglandin E2 release in macrophages even in the absence of T. cruzi infection and decreased NO production by LPS-stimulated macrophages. Oral supplementation of animals with corn oil (CO) or fish oil (FO) prevented the increase of parasitemia in animals pre-treated with EVs Y. In addition, stimulation with EVs Y did not abrogate NO production by splenocytes from animals supplemented with FO, indicating that ingestion of FO rich in n-3 PUFAs hinders the modulatory effects of EVs Y upon the response of animals to infection. In vitro, the treatment of macrophages with arachidonic acid associated with EVs Y increased the internalization of parasites in these cells, while the treatment with eicosapentaenoic acid associated with EVs Y decreased the internalization of parasites. Macrophages treated with linoleic or oleic acid had greater release of trypomastigotes, which was potentiated by the association of these fatty acids with EVs Y. In macrophages treated with arachidonic, eicosapentaenoic or docosahexaenoic acids there was no release of trypomastigotes, even when associated with EVs Y. These results suggest that EVs Y modulate the host response in favor of the parasite, while n-3 PUFAs interfere with the modulation exerted by EVs Y

Extracellular Vesicles Shed By Trypanosoma cruzi Potentiate Infection and Elicit Lipid Body Formation and PGE2 Production in Murine Macrophages

During the onset of Trypanosoma cruzi infection, an effective immune response is necessary to control parasite replication and ensure host survival. Macrophages have a central role in innate immunity, acting as an important trypanocidal cell and triggering the adaptive immune response through antigen presentation and cytokine production. However, T. cruzi displays immune evasion mechanisms that allow infection and replication in macrophages, favoring its chronic persistence. One potential mechanism is the release of T. cruzi strain Y extracellular vesicle (EV Y), which participate in intracellular communication by carrying functional molecules that signal host cells and can modulate the immune response. The present work aimed to evaluate immune modulation by EV Y in C57BL/6 mice, a prototype resistant to infection by T. cruzi strain Y, and the effects of direct EV Y stimulation of macrophages in vitro. EV Y inoculation in mice prior to T. cruzi infection resulted in increased parasitemia, elevated cardiac parasitism, decreased plasma nitric oxide (NO), reduced NO production by spleen cells, and modulation of cytokine production, with a reduction in TNF-α in plasma and decreased production of TNF-α and IL-6 by spleen cells from infected animals. In vitro assays using bone marrow-derived macrophages showed that stimulation with EV Y prior to infection by T. cruzi increased the parasite internalization rate and release of infective trypomastigotes by these cells. In this same scenario, EV Y induced lipid body formation and prostaglandin E2 (PGE2) production by macrophages even in the absence of T. cruzi. In infected macrophages, EV Y decreased production of PGE2 and cytokines TNF-α and IL-6 24 h after infection. These results suggest that EV Y modulates the host response in favor of the parasite and indicates a role for lipid bodies and PGE2 in immune modulation exerted by EVs

Aspirin Modulates Innate Inflammatory Response and Inhibits the Entry of Trypanosoma cruzi in Mouse Peritoneal Macrophages

The intracellular protozoan parasite Trypanosoma cruzi causes Chagas disease, a serious disorder that affects millions of people in Latin America. Cell invasion by T. cruzi and its intracellular replication are essential to the parasite’s life cycle and for the development of Chagas disease. Here, we present evidence suggesting the involvement of the host’s cyclooxygenase (COX) enzyme during T. cruzi invasion. Pharmacological antagonist for COX-1, aspirin (ASA), caused marked inhibition of T. cruzi infection when peritoneal macrophages were pretreated with ASA for 30 min at 37°C before inoculation. This inhibition was associated with increased production of IL-1β and nitric oxide (NO∙) by macrophages. The treatment of macrophages with either NOS inhibitors or prostaglandin E2 (PGE2) restored the invasive action of T. cruzi in macrophages previously treated with ASA. Lipoxin ALX-receptor antagonist Boc2 reversed the inhibitory effect of ASA on trypomastigote invasion. Our results indicate that PGE2, NO∙, and lipoxins are involved in the regulation of anti-T. cruzi activity by macrophages, providing a better understanding of the role of prostaglandins in innate inflammatory response to T. cruzi infection as well as adding a new perspective to specific immune interventions

Image_1_Extracellular Vesicles Shed By Trypanosoma cruzi Potentiate Infection and Elicit Lipid Body Formation and PGE2 Production in Murine Macrophages.PDF

<p>During the onset of Trypanosoma cruzi infection, an effective immune response is necessary to control parasite replication and ensure host survival. Macrophages have a central role in innate immunity, acting as an important trypanocidal cell and triggering the adaptive immune response through antigen presentation and cytokine production. However, T. cruzi displays immune evasion mechanisms that allow infection and replication in macrophages, favoring its chronic persistence. One potential mechanism is the release of T. cruzi strain Y extracellular vesicle (EV Y), which participate in intracellular communication by carrying functional molecules that signal host cells and can modulate the immune response. The present work aimed to evaluate immune modulation by EV Y in C57BL/6 mice, a prototype resistant to infection by T. cruzi strain Y, and the effects of direct EV Y stimulation of macrophages in vitro. EV Y inoculation in mice prior to T. cruzi infection resulted in increased parasitemia, elevated cardiac parasitism, decreased plasma nitric oxide (NO), reduced NO production by spleen cells, and modulation of cytokine production, with a reduction in TNF-α in plasma and decreased production of TNF-α and IL-6 by spleen cells from infected animals. In vitro assays using bone marrow-derived macrophages showed that stimulation with EV Y prior to infection by T. cruzi increased the parasite internalization rate and release of infective trypomastigotes by these cells. In this same scenario, EV Y induced lipid body formation and prostaglandin E₂ (PGE₂) production by macrophages even in the absence of T. cruzi. In infected macrophages, EV Y decreased production of PGE₂ and cytokines TNF-α and IL-6 24 h after infection. These results suggest that EV Y modulates the host response in favor of the parasite and indicates a role for lipid bodies and PGE₂ in immune modulation exerted by EVs.</p