Investigação do perfil de expressão gênica de receptores tipo toll e citocinas inflamatórias no encéfalo e no baço de cães com leishmaniose visceral
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Data
2017-08-17
Autores
Grano, Fernanda Grecco [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A leishmaniose visceral (LV) é uma doença parasitária que apresenta distribuição mundial e que pode afetar homens e animais, sendo que o cão é considerado o principal hospedeiro da doença. Cães infectados pelo parasito Leishmania podem apresentar-se assintomáticos ou com desordens generalizadas, incluindo alterações neurológicas. Existem alguns relatos do acometimento do encéfalo durante a infecção, mas a neuropatogenia da doença não foi completamente elucidada. Há evidências do comprometimento das barreiras encefálicas e da presença do DNA do parasito no encéfalo. Os receptores tipo Toll (TLRs) são sensores do sistema imune inato capazes de detectar padrões moleculares associados aos patógenos (PAMPs), desencadeando uma resposta inflamatórias com produção de diversos mediadores inflamatórios, incluindo citocinas. Desta forma, o objetivo deste estudo foi avaliar o perfil de expressão gênica dos Tolls 1-10, assim como a produção de citocinas pró-inflamatórias TNF-α, IFN-γ, IL-1β e IL-6 no encéfalo e no baço de cães com leishmaniose visceral. No baço houve aumento de expressão gênica de TLR-5 e TLR-9, enquanto no encéfalo houve aumento de TLR-4 em uma pequena população de cães infectados. Em relação às citocinas, todas as citocinas foram detectadas nos dois tecidos avaliados, com excessão de IL-6. Nos cães infectados, TNF-α e IL-1β estavam presentes em maiores concentrações no encéfalo e no baço, respectivamente. Este estudo fornece suporte para explicar o envolvimento de TLRs na LV e nossos dados confirmam o envolvimento encefálico durante a doença.
Visceral leishmaniasis (VL) is a parasitic disease that presents world distribution, affecting humans and animals. Dogs are considered the main hosts of the disease. Infected dogs with the Leishmania parasite can be asymptomatic or present generalized disorders, including neurological alterations. There are some reports of brain commitment during infection. Nevertheless, neuropathogenesis of VL is not completely elucidated. There are evidences of brain barriers breakdown and of the presence of Leishmania DNA in the brain. Toll-like receptors (TLRs) are innate immune sensors capable of detecting pathogen-associated molecular patterns (PAMPs), trigger an inflammatory response with production of several inflammatory mediators, including cytokines. Therefore, the aim of this study was to evaluate gene expression profile of TLRs1-10, along with the production of proinflammatory cytokines in both brain and spleen in dogs with VL. In spleen there was an upregulation of TLR-5 and TLR-9 while in the brain there was up-regulation of TLR- 4 in a few number of infected animals. Regarding cytokines, all cytokines were detected in both tissues, except IL-6. In the infected dogs, TNF-α and IL-1β were present at higher concentrations in the brain and spleen, respectively. This study provides support to explain the involvement of TLRs in VL and our data confirm the brain as an affected organ in this disease.
Visceral leishmaniasis (VL) is a parasitic disease that presents world distribution, affecting humans and animals. Dogs are considered the main hosts of the disease. Infected dogs with the Leishmania parasite can be asymptomatic or present generalized disorders, including neurological alterations. There are some reports of brain commitment during infection. Nevertheless, neuropathogenesis of VL is not completely elucidated. There are evidences of brain barriers breakdown and of the presence of Leishmania DNA in the brain. Toll-like receptors (TLRs) are innate immune sensors capable of detecting pathogen-associated molecular patterns (PAMPs), trigger an inflammatory response with production of several inflammatory mediators, including cytokines. Therefore, the aim of this study was to evaluate gene expression profile of TLRs1-10, along with the production of proinflammatory cytokines in both brain and spleen in dogs with VL. In spleen there was an upregulation of TLR-5 and TLR-9 while in the brain there was up-regulation of TLR- 4 in a few number of infected animals. Regarding cytokines, all cytokines were detected in both tissues, except IL-6. In the infected dogs, TNF-α and IL-1β were present at higher concentrations in the brain and spleen, respectively. This study provides support to explain the involvement of TLRs in VL and our data confirm the brain as an affected organ in this disease.
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Palavras-chave
Inflamação, Leishmania infantum, Sistema nervoso central, Central nervous system, Inflammation