Efeito da rapamicina em células de animais com encefalomielite autoimune experimental
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2019-02-22
Autores
Borim, Patricia Aparecida
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Universidade Estadual Paulista (Unesp)
Resumo
A rapamicina, também conhecida como sirolimus, é um imunossupressor isolado da bactéria Streptomyces hygroscopicus. Este fármaco tem sido empregado clínicamente para o controle de rejeição de transplantes de órgãos sólidos, diabetes, esclerose tuberosa, doenças neurode-generativas e inclusive, no controle da esclerose múltipla (EM). O entendimento do mecanis-mo de ação da rapamicina requer o conhecimento da via de sinalização intracelular envolvendo os complexos mTOR (mammalian target of rapamycin). Evidências indicam que o mTOR está envolvido na ativação pró-inflamatória de leucócitos. Nesse contexto, o objetivo geral desta dissertação foi investigar o efeito in vitro da rapamicina em células envolvidas na imu-nopatogênese da encefalomielite autoimune experimental (EAE), um modelo murino de EM. Células do sisterma nervoso central (SNC) e do baço de camundongos com EAE foram trata-das com rapamicina e simultaneamente estimuladas com glicoproteína da mielina de oligo-dendrócitos. A rapamicina reduziu a produção de IL-17 em culturas de células do SNC e do baço. Adicionalmente, diminuiu a produção de IFN-γ, TNF-α e IL-10 e a expressão gênica de RORc em culturas de células do SNC. A microglia, que é uma célula fagocítica residente no SNC e envolvida na neuroinflamação, também foi testada. Em células da microglia (linhagem BV-2) estimuladas com LPS, a rapamicina diminuiu a produção de TNF-α e IL-6 e também reduziu a mediana da intensidade da fluorescência referente às moléculas MHC II, CD40 e CD86. Este efeito imunossupressor foi associado à maior expressão gênica de TREM2 e me-nor expressão gênica de iNOS. Estes resultados indicaram que a rapamicina modula negati-vamente a ativação de células autorreativas e da microglia ativada. Portanto, propomos que outras moléculas candidatas à terapia da EM sejam inicialmente rastreadas usando essa abordagem.
Rapamycin, also known as sirolimus, is an immunosuppressant produced by the bacterium Streptomyces hygroscopicus. Rapamycin has been clinically used for the control of rejection of solid organ transplants, diabetes, tuberous sclerosis, neurodegenerative diseases, including multiple sclerosis (MS). To better understand the mechanism of action of rapamycin, is necessary the knowledge of intracellular signaling of the mTOR (mammalian target of rapamycin) complex. Evidence indicates that mTOR is involved in the proinflammatory activation of leukocytes. In this scenario, the main objective of this investigation was to evaluate the in vitro effect of rapamycin in cells derived from mice with experimental autoimmune encephalomielits (EAE) and in a microglia cell line. CNS and spleen cells from EAE mice were treated with rapamycin and simultaneosly stimulated with a myelin oligodendrocyte glycoprotein peptide. Rapamycin reduced IL-17 production in both, CNS and spleen cell cultures. Additionally, rapamycin decreased IFN-γ, TNF-α and IL-10 production and RORc mRNA expression in CNS cell cultures. Microglia, that is a phagocytic immune cell in the CNS involved in neuroinflammation, was also tested. Microglia (BV-2 lineage) treated simultaneously with rapamycin and LPS showed a decreased production of TNF-α and IL-6 and also reduced expression of MHC II, CD40 and CD86. This downmodulatory effect was associated to upregulated TREM2 mRNA and downregulated iNOS mRNA expression. These results indicated that rapamycin downmodulates the activation of autoreactive cells and activated microglia. We therefore propose that other MS therapy candidate molecules are initially screened by using this approach.
Rapamycin, also known as sirolimus, is an immunosuppressant produced by the bacterium Streptomyces hygroscopicus. Rapamycin has been clinically used for the control of rejection of solid organ transplants, diabetes, tuberous sclerosis, neurodegenerative diseases, including multiple sclerosis (MS). To better understand the mechanism of action of rapamycin, is necessary the knowledge of intracellular signaling of the mTOR (mammalian target of rapamycin) complex. Evidence indicates that mTOR is involved in the proinflammatory activation of leukocytes. In this scenario, the main objective of this investigation was to evaluate the in vitro effect of rapamycin in cells derived from mice with experimental autoimmune encephalomielits (EAE) and in a microglia cell line. CNS and spleen cells from EAE mice were treated with rapamycin and simultaneosly stimulated with a myelin oligodendrocyte glycoprotein peptide. Rapamycin reduced IL-17 production in both, CNS and spleen cell cultures. Additionally, rapamycin decreased IFN-γ, TNF-α and IL-10 production and RORc mRNA expression in CNS cell cultures. Microglia, that is a phagocytic immune cell in the CNS involved in neuroinflammation, was also tested. Microglia (BV-2 lineage) treated simultaneously with rapamycin and LPS showed a decreased production of TNF-α and IL-6 and also reduced expression of MHC II, CD40 and CD86. This downmodulatory effect was associated to upregulated TREM2 mRNA and downregulated iNOS mRNA expression. These results indicated that rapamycin downmodulates the activation of autoreactive cells and activated microglia. We therefore propose that other MS therapy candidate molecules are initially screened by using this approach.
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Palavras-chave
mTOR, Immunomodulation, Multiple sclerosis, Lymphocytes, Microglia, mTOR, Imunomodulador, Esclerose múltipla, Linfócitos, Microglia