Thymic microenvironmental alterations in different kind of thymus atrophy

Orientadores: Liana Verinaud, Wilson SavinoTese (doutorado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: O timo é o órgão linfóide primário responsável pelo amadurecimento dos linfócitos T. O processo de maturação é dependente da integridade do microambiente e da migração coordenada por elementos de matriz e quimiocinas dos precursores hematopoiéticos nos distintos nichos tímicos. Entretanto, a literatura mostra que profundas alterações no microambiente tímico, e conseqüentemente no desenvolvimento e amadurecimento dos linfócitos T, podem ocorrer como resultado de algumas patologias. No presente trabalho, analisamos a indução de atrofia e as alterações no microambiente tímico frente a três diferentes agentes indutores de atrofia, sendo dois agentes patogênicos, P.brasiliensis e P.berghei e uma doença metabólica, a diabetes induzida por aloxana. Nos três modelos estudados foi observada a atrofia do órgão com diferente intensidade nas alterações de componentes do microambiente tímico. Importantes moléculas associadas com a migração intratímica mostraram-se alteradas com modificações significativas nos elementos de matriz e nas quimiocinas bem como na expressão dos seus respectivos receptores. Ainda, a migração ex vivo também se mostrou alterada na atrofia induzida pelos agentes patogênicos, mas não no modelo de atrofia induzido por aloxana, sugerindo que as alterações desencadeadas são específicas de cada condição patológica analisada. As modificações nos elementos estudados sugerem alterações no padrão de migração intratímica e na exportação de timócitos, com comprometimento da função tímica, levando a maturação desequilibrada dos timócitos, com conseqüências para a resposta imune periférica.Abstract: Thymus is the primary lymphoid organ responsible for differentiation of Tlymphocytes. This process is dependent of thymic microenvironment integrity and coordinated migration of hematopoietic precursors by chemokines and extracellular matrix elements. However, the literature shows that deep alterations in thymus microenvironment with modifications in thymocyte development may occur such as result of some pathological disorders. In this study we analyzed the atrophy induction and alterations in thymic microenvironment in three different models of thymus atrophy. We studied two models of infectious diseases, P.brasiliensis and P.berghei, and a metabolic disorder, alloxan induced diabetes. We have observed thymus atrophy in all models with different alterations levels in thymus microenvironment elements. Important molecules associated with intrathymic migration were been altered with significant modifications in extracellular matrix elements, chemokines and their specific receptors. Besides, ex vivo migration was altered in thymus atrophy induced by pathogenic agents, but no alterations were observed in diabetic mice suggesting that different pathological conditions studied, leads to singular alterations in thymus compartment. The modifications in thymic molecules observed in our models, suggest impaired thymus functionality and alterations in thymocyte migration patterns These alterations can lead T cell maturation imbalance with consequences in Tlymphocyte immune response.DoutoradoImunologiaDoutor em Genetica e Biologia Molecula

A high-fat diet protects C57BL/6 mice from Plasmodium berghei ANKA infection in an experimental malaria study

IntroductionIt is well known that dietary changes have a significant impact on the immune system, and modifications in lipid balance may contribute to disease progression in several cases. Malaria is still a major global health concern, and the development of the disease has already been linked to the host’s nutritional status, so it’s critical to understand how environmental factors, such as dietary variations, can influence the outcome of infection. We therefore investigated the effect of a short-term diet in a murine model of experimental cerebral malaria.MethodsFor this, male C57BL/6 mice were fed a high fat diet containing 60% of the calories from lipids for 5 days. Following this period, the animals were infected with Plasmodium berghei ANKA, and parasitemia, survival, and neurological scores were compared. Considering that one of the first elimination routes of the intracellular parasite is oxidative stress, the antioxidant N-acetylcysteine was administered to assess whether the protection would be reversed.Results and discussionAnimals fed a hyperlipidic diet reacted the same way to infection even after NAC administration. Unlike the control group, which died after eight days of infection with roughly 7% parasitized red blood cells, the hyperlipidic diet group was resistant to infection, with no clinical signs and no increase in blood parasitemia. Several proinflammatory cytokines such as TNF-α IFN-γ and IL-6 were increased in the spleen of both infected groups, regardless of their diet. The provision of a high-fat diet to mice for as little as 5 days completely prevents Plasmodium berghei ANKA infection in C57BL/6 mice, while the treatment of an antioxidant failed to reverse the parasite protection

Expression of an scFv antibody fragment in Nicotiana benthamiana and in vitro assessment of its neutralizing potential against the snake venom metalloproteinase BaP1 from Bothrops asper

Human accidents with venomous snakes represent an overwhelming public health problem, mainly in rural populations of underdeveloped countries. Their high incidence and the severity of the accidents result in 81,000 to 138,000 deaths per year. The treatment is based on the administration of purified antibodies, produced by hyper immunization of animals to generate immunoglobulins (Igs), and then obtained by fractionating hyper immune plasma. The use of recombinant antibodies is an alternative to conventional treatment of snakebite envenoming, particularly the Fv fragment, named the single-chain variable fragment (scFv). We have produced recombinant single chain variable fragment scFv against the venom of the pit viper Bothrops asper at high levels expressed transiently and stably in transgenic plants and in vitro cultures that is reactive to BaP1 (a metalloproteinase from B. asper venom). The yield from stably transformed plants was significantly (p > 0.05) higher than the results in from transient expression. In addition, scFvBaP1 yields from systems derived from stable transformation were: transgenic callus 62 μg/g (±2); biomass from cell suspension cultures 83 μg/g (±0.2); culture medium from suspensions 71.75 mg/L (±6.18). The activity of scFvBaP1 was confirmed by binding and neutralization of the fibrin degradation induced by BnP1 toxins from B. neuwiedi and by Atroxlysin Ia from B. atrox venoms. In the present work, we demonstrated the potential use of plant cells to produce scFvBaP1 to be used in the future as a biotechnological alternative to horse immunization protocols to produce anti-venoms to be used in human therapy against snakebites.Fil: Gomes, Marinna. Universidade Federal de Juiz de Fora; BrasilFil: Alvarez, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides; ArgentinaFil: Quellis, Leonardo Ramos. Universidade Federal de Juiz de Fora; BrasilFil: Laguía Becher, Melina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides; ArgentinaFil: Castro, Juciane Maria de Andrade. Universidade Federal de Juiz de Fora; BrasilFil: Gameiro, Jacy. Universidade Federal de Juiz de Fora; BrasilFil: Caporrino, Maria Cristina. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: Silva, Ana Maria Moura da. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: Santos, Marcelo de Oliveira. Universidade Federal de Juiz de Fora; Brasi

Pereskia aculeata Miller leaves present in vivo topical anti-inflammatory activity in models of acute and chronic dermatitis

AbstractEthnopharmacological relevance: The leaves of Pereskia aculeata Miller (Cactaceae), known as Barbados gooseberry, are used in Brazilian traditional medicine as emollients and to treat skin wounds and inflammation. This study investigated the topical anti-inflammatory activity of the hexane fraction (HF) obtained from the methanol extract of the leaves of this species in models of acute and chronic ear dermatitis in mice.Material and methods: Mice ear edema was induced by topical application of croton oil, arachidonic acid, capsaicin, ethyl-phenylpropiolate and phenol; and by subcutaneous injection of histamine. Ear biopsies were obtained to determine the levels of IL-1β, IL-6 and TNF-α cytokines by ELISA assay. Histopathological analysis was also performed to evaluate the HF activity in croton oil multiple application test. In addition, acute dermal irritation/corrosion test in rats was accomplished. HF chemical characterization was performed by GC–MS analysis.Results: HF intensively reduced the inflammatory process induced by all irritant agents used, except for arachidonic acid. This activity is related, at least in part, to the reduction of IL-6 and TNF-α cytokines levels. Moreover, when the glucocorticoid receptor antagonist mifepristone was used, HF failed to respond to the croton oil application.The results strongly suggested a glucocorticoid-like effect, which was reinforced by the presence of considerable amounts of sterol compounds identified in HF. The acute dermal irritaton/corrosion test showed no signs of toxicity.Conclusions: This study showed that the acute and chronic anti-inflammatory activity of P. aculeata leaves is very promising, and corroborates to better understand their ethnopharmacological applications

COVID-19 and Obesity: An Epidemiologic Analysis of the Brazilian Data

Brazil has the second highest number of deaths due to COVID-19. Obesity has been associated with an important role in disease development and a worse prognosis. We aimed to explore epidemiological data from Brazil, discussing the potential relationships between obesity and COVID-19 severity in this country. We used a public database made available by the Ministry of Health of Brazil (182700 patients diagnosed with COVID-19). Descriptive statistics were used to characterize our database. Continuous data were expressed as median and analyzed by the nonparametric tests Mann–Whitney or one-sample Wilcoxon. The frequencies of categorical variables have been analyzed by chi-square tests of independence or goodness-of-fit. Among the number of deaths, 74% of patients were 60 years of age or older. Patients with obesity who died of COVID-19 were younger (59 years (IQR = 23)) than those without obesity (71 years (IQR = 20), P<0.001, and η2 = 0.0424). Women with obesity who died of COVID-19 were older than men (55 years (IQR = 25) vs. 50 (IQR = 22), P<0.001, and η2 = 0.0263). Furthermore, obesity increases the chances of needing intensive care unit (OR: 1.783, CI: 95%, and P<0.001), needing ventilatory support (OR: 1.537, CI: 95%, and P<0.001 and OR: 2.302, CI: 95%, and P<0.001, for noninvasive and invasive, respectively), and death (OR: 1.411, CI: 95%, and P<0.001) of patients hospitalized with COVID-19. Our analysis supports obesity as a significant risk factor for the development of more severe forms of COVID-19. The present study can direct a more effective prevention campaign and appropriate management of subjects with obesity

Papel da microbiota na modulação da homeostase dos hospedeiros: correlação entre micobioma intestinal e obesidade

Os fungos apresentam papel importante na saúde humana, sendo componentes da microbiota humana de diversos sítios anatômicos como, por exemplo, pele, cavidade bucal, trato gastrintestinal e trato geniturinário. São também agentes etiológicos de várias infecções, desde micoses superficiais até sistêmicas. Os fungos participam na regulação do sistema imunológico, podendo promover o surgimento de alergias das vias aéreas superiores. Estão presentes na composição da microbiota intestinal, formando o micobioma. Portanto, seu papel no desenvolvimento da obesidade deve ser considerado, atuando tanto na modulação da resposta imune local quanto através de sua interação com os demais microrganismos da microbiota intestinal. Este trabalho tem como objetivo revisar aspectos da participação microbiana na etiopatogenia da obesidade e discutir a participação dos fungos no microbioma intestinal, sua relação com a obesidade e as perspectivas futuras, com a utilização de metodologias moleculares, para um melhor entendimento do papel dos fungos na microbiota intestinal na saúde e na doença

Atrofia tímica e virulência fúngica durante a paracoccidioidomicose experimental

The immunosuppression observed in systemic mycosis can be related to primary lymphoid organs damage. Thus, our laboratory has studied the effects of the Paracoccidioides brasiliensis infection on the thymus of mice. Here, thymuses of susceptible and resistant mice were evaluated after inoculation with highly and slightly virulent isolates of the fungus. All groups presented thymic atrophy, loss of corticomedullary delimitation and increase of apoptotic index. However, mice inoculated with high virulent strain showed earlier and stronger alterations suggesting that thymic atrophy can be directly related to the fungal virulence and to the immunosuppression.A imunossupressão observada em micoses sistêmicas pode estar relacionada a danos nos órgãos linfóides primários. Assim, nosso laboratório tem estudado uma possível ação do Paracoccidioides brasiliensis sobre o timo de camundongos. Neste estudo, analisamos o timo de camundongos susceptíveis e resistentes ao fungo utilizando cepas de alta e baixa virulência. Todos os grupos apresentaram atrofia tímica, perda de delimitação corticomedular e aumento da taxa de apoptose. Entretanto, as alterações foram mais precoces e pronunciadas em camundongos inoculados com a cepa virulenta do fungo, sugerindo que a virulência fúngica pode estar diretamente ligada à atrofia tímica e indução de imunossupressão.1416Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES