Efeito da infecção com Candida albicans no desenvolvimento da Encefalomielite Autoimune Experimental
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Data
2016-02-25
Autores
Fraga-Silva, Thais Fernanda de Campos [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A esclerose múltipla é uma doença autoimune ainda sem cura que acomete o sistema nervoso central (SNC). Evidências observadas em pacientes e em modelos experimentais indicam que infecções fúngicas e/ou derivados fúngicos podem contribuir com a patogênese da doença. Neste contexto, o objetivo deste projeto foi avaliar o efeito da infecção por Candida albicans e derivados fúngicos no desenvolvimento da encefalomielite autoimune experimental (EAE) que é o modelo murino desta patologia. Para avaliar o papel da infecção, camundongos C57BL/6 foram infectados com C. albicans três dias antes da indução da EAE. A infecção prévia agravou os sinais clínicos da doença. Este agravamento foi relacionado com a disseminação do fungo para o SNC e aumento da produção de citocinas encefalitogênicas (TNF-a, IL-6, IL-17 e IFN-y) tanto na periferia (baço) quanto no SNC. Para avaliar o efeito de derivados fúngicos no desenvolvimento da EAE, camundongos foram inoculados com três doses de gliotoxina ou de leveduras mortas de C. albicans após a indução da doença. A inoculação de gliotoxina resultou em sintomatologia mais grave, associada com um intenso infiltrado inflamatório e maior produção de TNF-a no SNC. De forma distinta a inoculação de leveduras mortas resultou em uma doença bem mais branda, com menor porcentagem de células apoptóticas e baixa produção de citocinas encefalitogênicas no SNC. Considerando que recentemente nosso grupo de pesquisa demonstrou que a vacinação com MOG associada à vitamina D (MOG+VitD) preveniu a encefalomielite, investigamos também se a infecção por C. albicans é capaz de quebrar a tolerância induzida por esta vacinação. Para isto, camundongos foram vacinados com MOG+VitD, infectados com C. albicans e depois submetidos à indução da EAE. A vacinação determinou proteção caracterizada por melhora significativa da sintomatologia, decréscimo acentuado na produção de citocinas encefalitogênicas no baço e no SNC e expansão de células T reguladoras. No seu conjunto os resultados desta investigação indicam que derivados fúngicos, dependendo de suas características, podem ser deletérios ou protetores no desenvolvimento da EAE.
Multiple sclerosis (MS) is an autoimmune disease that affects the central nervous system (CNS). Data from patients and experimental models suggest that fungal infection and fungalderived antigens could contribute to the immunopathogenesis of this pathology. The main objective of this research was to investigate the effect of C. albicans and fungal derivatives on experimental autoimmune encephalomyelitis (EAE) that is a widely employed animal model to study MS. Initially, C57BL/6 mice were infected with C. albicans and three days later they were submitted to EAE induction. Infected animals developed a more severe disease associated with fungus spread to the CNS and increased production of encephalitogenic cytokines as TNF-α, IL-6, IL-17 and IFN-γ by cells from the spleen and the CNS. To test the effect of fungal derivatives mice were submitted to EAE induction and then injected with three doses of gliotoxin or dead yeasts of C. albicans. Gliotoxin inoculation resulted in clinical disease aggravation, higher local inflammatory infiltration and higher production of TNF-α by the CNS. Dead C. albicans inoculation determined a less severe disease associated with a lower production of encephalitogenic cytokines and a lower degree of apoptosis by CNS eluted cells. Lastly we demonstrated that C. albicans infection did not disrupt the prophylactic efficacy of MOG+VitD tolerogenic vaccination. Even in infected mice this vaccine decreased clinical signs, downmodulated the production of encephalitogenic cytokines and also increased the percentage of regulatory T cells. All together these results indicate that C. albicans infection and gliotoxin inoculation aggravate EAE development whereas dead C. albicans inoculation protected the animals.
Multiple sclerosis (MS) is an autoimmune disease that affects the central nervous system (CNS). Data from patients and experimental models suggest that fungal infection and fungalderived antigens could contribute to the immunopathogenesis of this pathology. The main objective of this research was to investigate the effect of C. albicans and fungal derivatives on experimental autoimmune encephalomyelitis (EAE) that is a widely employed animal model to study MS. Initially, C57BL/6 mice were infected with C. albicans and three days later they were submitted to EAE induction. Infected animals developed a more severe disease associated with fungus spread to the CNS and increased production of encephalitogenic cytokines as TNF-α, IL-6, IL-17 and IFN-γ by cells from the spleen and the CNS. To test the effect of fungal derivatives mice were submitted to EAE induction and then injected with three doses of gliotoxin or dead yeasts of C. albicans. Gliotoxin inoculation resulted in clinical disease aggravation, higher local inflammatory infiltration and higher production of TNF-α by the CNS. Dead C. albicans inoculation determined a less severe disease associated with a lower production of encephalitogenic cytokines and a lower degree of apoptosis by CNS eluted cells. Lastly we demonstrated that C. albicans infection did not disrupt the prophylactic efficacy of MOG+VitD tolerogenic vaccination. Even in infected mice this vaccine decreased clinical signs, downmodulated the production of encephalitogenic cytokines and also increased the percentage of regulatory T cells. All together these results indicate that C. albicans infection and gliotoxin inoculation aggravate EAE development whereas dead C. albicans inoculation protected the animals.
Descrição
Palavras-chave
Candida albicans, Candidíase sistêmica, Encefalomielite autoimune experimental, Esclerose múltipla, Candida albicans, Candidíase sistêmica, Experimental autoimmune encephalomyelitis, Multiple sclerosis