Impacto da eferocitose de células infectadas pelo Zika vírus na ativação de células dendríticas
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Data
2019-12-20
Autores
Avelar, Matheus Rossi [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Estudos recentes demonstram que a eferocitose de células apoptóticas infectadas por células dendríticas (CD) resulta na ativação de clones de linfócitos T CD4+ autorreativos e o desenvolvimento de doenças autoimunes. O processamento e apresentação de peptídeos próprios oriundos das células apoptóticas via MHC, associado a presença do patógeno, permite a indução de um fenótipo imunogênico nessas CD, e, portanto, propiciando o ambiente favorável para ativação de clones autorreativos. A infecção pelo vírus Zika (ZIKV) vem sendo amplamente estudada devido às complicações neuronais no desenvolvimento fetal e em adultos, como a microcefalia e síndrome de Guillain-Barré, respectivamente. Considerando que a infecção pelo ZIKV induz intensa morte celular por apoptose em diferentes tipos celulares, a hipótese deste estudo fundamenta-se que a fagocitose de células apoptóticas infectadas pelo ZIKV levaria a ativação de CD com um perfil imunogênico. Para investigar o efeito da eferocitose na ativação de células dendríticas, inicialmente duas cepas viras e diferentes linhagens celulares foram testadas para obtenção de células infectadas por ZIKV. O potencial de infecção das cepas virais ZIKV PE243 (linhagem asiática isolada no Brasil) e ZIKV MR766 (linhagem africana isolada em Uganda) foram testadas utilizando cinco linhagens celulares: HaCaT, A549, Huh7.5, C6 e SH-SY5Y. As linhagens HaCaT, A549 e C6 apresentaram baixa infectividade, enquanto as linhagens Huh7.5 e SH-SY5Y mostraram alta taxa de infecção pela cepa ZIKV PE234. A eferocitose de células Huh7.5 infectadas pelo ZIKV não foi capaz de induzir um aumento na expressão de moléculas de MHC-II em células dendríticas derivadas de medula óssea (BMDC) e apresentou uma produção mista de Il-6 e IL-10, sugerindo um perfil não definido. No entanto, a eferocitose de células da linhagem neuronal SH-SY5Y infectadas pelo ZIKV levou ao aumento na expressão das moléculas CD86 e MHC-II nas BMDC, além de uma maior produção das citocinas IL-1β, IL-6 e TGF-β quando comparada ao controle de células SH-SY5Y não infectadas. Esse perfil de BMDC e de citocinas inflamatórias após a eferocitose de SH-SY5Y infectadas pelo ZIKV reforça nossa hipótese inicial, ou seja, que apresenta potencial para ativar células T autorreativas. No entanto, novos experimentos utilizando células T isoladas de animais transgênicos OT-II serão necessários para confirmar essa hipótese.
Recent studies show that phagocytosis of infected apoptotic cells by dendritic cells (CD) results in activation of self-reactive CD4+ T lymphocytes clones and the development of autoimmune diseases. The processing of self-peptides associated with the presence of the pathogen inside the apoptotic cells allows the induction of an immunogenic phenotype in these dendritic cells, thus providing a favorable environment for activation of self-reactive T CD4+ clones. Zika virus (ZIKV) infection has been widely studied due to neuronal complications in fetal development and in adults such as microcephaly and Guillain-Barré syndrome, respectively. Considering that ZIKV infection induces intense apoptotic cell death in different cell types, the hypothesis of this study was that the phagocytosis of ZIKV infected apoptotic cells would lead to activation of dendritic cells in an immunogenic profile. To investigate the effect of efferocytosis of infected cells on dendritic cell activation, two strains and different cell lineages were tested to obtain ZIKV infected cells. Infection potential of viral strains ZIKV PE243 (Asian strain isolated in Brazil) and ZIKV MR766 (African strain isolated in Uganda) were tested using five cell lineages: HaCaT, A549, Huh7.5, C6 e SH-SY5Y. HaCaT, A549 and C6 cell lineages showed low susceptibility to the ZIKV PE243 strain while Huh7.5 and SH-SY5Y showed high infection rate. Efferocytosis of ZIKV infected Huh7.5 cells was not able to induce an increase in MHCII molecule expression in bone marrow-derived dendritic cells (BMDC) and a mixed cytokine production of IL-6 and IL-10, indicating non defined profile. However, the eferocytosis of cells from the ZIKV infected SH-SY5Y neuronal lineage caused a higher expression of CD86 and MHCII molecules in BMDC, as well as a higher production of IL-1β, IL-6 and TGF-β cytokines when compared to uninfected SH-SY5Y cells. This immunogenic profile of BMDC and inflammatory cytokines produced after the coculture of ZIKV-infected SH-SY5Y confirms our initial hypothesis, that there is potential to activate autoreactive T cells. However, further experiments will be performed using T cells isolated from OT-II transgenic animals to confirm this hypothesis.
Recent studies show that phagocytosis of infected apoptotic cells by dendritic cells (CD) results in activation of self-reactive CD4+ T lymphocytes clones and the development of autoimmune diseases. The processing of self-peptides associated with the presence of the pathogen inside the apoptotic cells allows the induction of an immunogenic phenotype in these dendritic cells, thus providing a favorable environment for activation of self-reactive T CD4+ clones. Zika virus (ZIKV) infection has been widely studied due to neuronal complications in fetal development and in adults such as microcephaly and Guillain-Barré syndrome, respectively. Considering that ZIKV infection induces intense apoptotic cell death in different cell types, the hypothesis of this study was that the phagocytosis of ZIKV infected apoptotic cells would lead to activation of dendritic cells in an immunogenic profile. To investigate the effect of efferocytosis of infected cells on dendritic cell activation, two strains and different cell lineages were tested to obtain ZIKV infected cells. Infection potential of viral strains ZIKV PE243 (Asian strain isolated in Brazil) and ZIKV MR766 (African strain isolated in Uganda) were tested using five cell lineages: HaCaT, A549, Huh7.5, C6 e SH-SY5Y. HaCaT, A549 and C6 cell lineages showed low susceptibility to the ZIKV PE243 strain while Huh7.5 and SH-SY5Y showed high infection rate. Efferocytosis of ZIKV infected Huh7.5 cells was not able to induce an increase in MHCII molecule expression in bone marrow-derived dendritic cells (BMDC) and a mixed cytokine production of IL-6 and IL-10, indicating non defined profile. However, the eferocytosis of cells from the ZIKV infected SH-SY5Y neuronal lineage caused a higher expression of CD86 and MHCII molecules in BMDC, as well as a higher production of IL-1β, IL-6 and TGF-β cytokines when compared to uninfected SH-SY5Y cells. This immunogenic profile of BMDC and inflammatory cytokines produced after the coculture of ZIKV-infected SH-SY5Y confirms our initial hypothesis, that there is potential to activate autoreactive T cells. However, further experiments will be performed using T cells isolated from OT-II transgenic animals to confirm this hypothesis.
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Palavras-chave
vírus Zika, eferocitose, ativação celular, efferocytosis