Unbalanced relationships: insights into the interaction between gut microbiota, geohelminths, and schistosomiasis.

Hosts and their microbiota and parasites have co-evolved in an adaptative relationship since ancient times. The interaction between parasites and intestinal bacteria in terms of the hosts' health is currently a subject of great research interest. Therapeutic interventions can include manipulations of the structure of the intestinal microbiota, which have immunological interactions important for modulating the host's immune system and for reducing inflammation. Most helminths are intestinal parasites; the intestinal environment provides complex interactions with other microorganisms in which internal and external factors can influence the composition of the intestinal microbiota. Moreover, helminths and intestinal microorganisms can modulate the host's immune system either beneficially or harmfully. The immune response can be reduced due to co-infection, and bacteria from the intestinal microbiota can translocate to other organs. In this way, the treatment can be compromised, which, together with drug resistance by the parasites makes healing even more difficult. Thus, this work aimed to understand interactions between the microbiota and parasitic diseases caused by the most important geohelminths and schistosomiasis and the consequences of these associations.

Explorando os estresses oxidativo e nitrosativo contra fungos: um mecanismo subjacente à ação de tradicionais antifúngicos e um potencial novo alvo terapêutico na busca por indutores oriundos de fontes naturais / Explorando los estréses oxidativos y nitrosativos contra hongos: un mecanismo subyacente a la acción de los antifúngicos tradicionales y un potencial nuevo objetivo terapéutico en la búsqueda de inductores de fuentes naturales / Exploring the oxidative and nitrosative stresses against fungi: an underlying mechanism beyond the action of traditional antifungal agents and a potential new therapeutic target in searching for inducers from natural sources

RESUMO Objetivo: Nesta revisão sistemática, nós avaliamos o link entre indutores de estresse oxidativo e/ou nitrosativo (EO/EN) com atividade antifúngica, através de uma ação direta sobre a célula fúngica e/ou modulando a resposta de fagócitos contra fungos de interesse médico (incluindo Candida spp., Cryptococcus spp. e Aspergillus spp.). Ainda, foram avaliadas as implicações clínicas deste evento bioquímico, bem como as perspectivas quanto à busca por novos compostos com atividade antifúngica, principalmente, os provenientes de fonte natural e, que explorem a indução de um EO ou EN como parte de seu mecanismo de ação. Metodologia: Foram avaliados artigos, provenientes de diferentes bases de dados e publicados a qualquer período, acessados entre abril e junho de 2017, através da utilização de diferentes descritores. Resultados: Primeiramente, estabelecemos as definições de EO/EN, como sendo o aumento das concentrações de espécies reativas do oxigênio e/ou nitrogênio (ERO/ ERN) quantificado diretamente e, provenientes de fontes fúngicas mitocondriais, Reação de Fenton, retículo endoplasmático ou outras não definidas, e excedendo a capacidade de defesa antioxidante do microrganismo (avaliados por análises de perfis transcriptômicos ou proteômicos ou metabolômicos ou níveis de atividade enzimática). Este aumento de ERO/ERN causando EO/EN é definido por tempo e condições que conduzem a sinalização de apoptose ou reais danos a biomoléculas com perda de função (peroxidação lipídica ou oxidação proteica ou danos ao DNA) e, consequentemente, gerando morte fúngica ou outro efeito antifúngico associado. Portanto, 64 artigos (apenas um publicado antes do ano 2000 e 50 entre 2007-2017) abordam que a indução de EO ou EN na célula fúngica é parte do mecanismo de ação de clássicos agentes antifúngicos (22 publicações), tais como azóis (fluconazol, itraconazol e miconazol), polienos (anfotericina B [AnB]) e equinocandinas (mica-fungina), assim como tal modulação redox tem sido reportada como um importante alvo terapêutico na busca por novos e promissores compostos naturais com atividade antifúngica (32 publicações), que tem respaldo pela grande variedade de indutores que podem provir da natureza. Ainda, compostos que também induzem o burst oxidativo de fagócitos, incluindo AnB, são potencializadores do efeito antifúngico in vivo. Além do efeito antifúngico contra células planctônicas, os efeitos dos EO ou EN sobre biofilmes fúngicos, também têm sido reportados. Tem sido firmado na literatura recente um claro link entre EO ou EN e a atividade antifúngica, tanto para aqueles agentes antifúngicos já utilizados na terapêutica em humanos, quanto para possíveis candidatos a fármaco. Portanto, a indução do EO ou EN como parte do mecanismo de ação de antifúngicos demonstra ser um importante alvo terapêutico, com perspectivas favoráveis sobre os desfechos na prática clínica.

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SUMMARY Aim: In this systematic review, we evaluated the link between inducers of oxidative or nitrosative stresses (OS/NS) and antifungal activity against fungi of medical relevance (including Candida spp., Cryptococcus spp., and Aspergillus spp.), through a direct action on the fungal cell or modulating phagocyte response. Moreover, the clinical implications of this biochemical event, as well as the perspectives, were examined, highlighting the search for new compounds with antifungal activity, mainly those from natural sources and, which explores the induction of OS or NS as part of the mechanism of action. Methodology: Articles from different databases and published at any time were evaluated, between April and June 2017, and using different descriptors. Results: First, a definition of OS and NS was established in which an increase in reactive oxygen or nitrogen species (ROS/ RNS, quantified directly and from mitochondrial, Fenton reaction, endoplasmic reticulum or other fungal sources) should exceed the antioxidant defense capacity of the microorganism (evaluated by transcriptomic or proteomic or metabolomic profiles or enzyme activity levels). These events, by time and conditions delimited, can lead to the signaling of apoptosis or an actual damage toward biomolecules (lipid peroxidation or protein oxidation or DNA damage) and, consequently, they can cause cell death or other associated antifungal effect. Therefore, 64 articles were found, of these, only one was published before 2000 and 50 between 20072017, reporting the induction of OS or NS directly into the fungal cell via an increase in ROS or RNS as part of the mechanism of action of classical antifungal agents (22 publications), such as: azoles (fluconazole, itraconazole, and miconazole), polyenes (amphotericin B, [AnB]), and echinocandins (micafungin). This redox modulation has also been reported as an important therapeutic target in the search for new natural compounds with antifungal activity (32 publications), which is supported for the great variety of inducers from nature. Compounds that also induce the oxidative burst of phagocytes, including AnB, promote a combinatorial antifungal effect in vivo. In addition to the antifungal effect against plank-tonic cells, the relation between OS or NS and antifungal activity against fungal biofilms has also been reported. It has been established in the recent literature a clear link between OS or NS and antifungal effect, during the action of anti-fungal agents already used in the therapy in humans as well as for possible drug candidates. Thus, the induction of OS or NS as part of the mechanism of action proves to be an important therapeutic target with favorable perspectives on the outcomes in clinical practice.

Serum albumin nanoparticles vaccine provides protection against a lethal Pseudomonas aeruginosa challenge.

Pseudomonas aeruginosa is an opportunistic pathogen that causes severe infections in immunocompromised individuals and in patients with cystic fibrosis. A range of vaccines to prevent infections caused by P. aeruginosa has already been tested, yet no vaccine against this pathogen is currently available. The goal of this study was to evaluate the potential of bovine serum albumin nanoparticles (BSA-NPs) associated with total P. aeruginosa ATCC 27853 antigens in inducing protection against the infection with virulent P. aeruginosa PA14 strain in murine model of nasal infection. Swiss mice were immunized with BSA-NPs associated with total P. aeruginosa antigens (NPPa) or empty NPs (NPe). As positive and negative control, groups of animals were immunized with total antigens of P. aeruginosa ATCC 27853 and phosphate buffered saline, respectively. Immunized mice were infected via nasal route using P. aeruginosa PA14 strain. The survival after 48 h was evaluated and the lungs from animals were processed for quantification of bacterial load, cytokine expression and histopathological analysis. After infection with P. aeruginosa PA14, animals immunized with NPPa had the highest survival rate, the lowest bacterial lung load, a controlled production of cytokines and few histopathological changes. These results indicate that NPPa immunization protected mice from infection, contributing for the elimination of the bacteria from the lungs, which consequently reflected the survival of the animals. Therefore, this vaccine was able to induce a functional response in an animal model of lethal infection and thereby is a promising platform for P. aeruginosa vaccines.