Publicação
Role of reactive oxygen species in inflammasome activation in microgalia under stress conditions
| Resumo: | Introduction: Microglial cells are the resident immune cells of the Central Nervous System (CNS) intervening in adaptive immune responses by activating the inflammasome, which converts pro-IL-1β to its active form in response to diverse stimuli such as endoplasmic reticulum stress (ER stress) that is induced by the overload of misfolded protein in the ER lumen. Both ER stress and activation of inflammasome have been implicated in the pathogenesis of neurodegenerative diseases, namely in Alzheimer’s disease (AD). However, the relationship between changes in ER proteostasis and neuroinflammation is still unclear. In this work we studied the involvement of ER stress in activation of the NLRP3 inflammasome in microglia. Methods: ER stress was induced in the microglia cell line BV2 with brefeldin A (BFA). Using Western blot, MTT, Amplex Red and ELISA assays, the levels of ER stress markers, cell viability, inflammasome activation and generation of reactive oxygen species (ROS) were evaluated. Results: We demonstrated that ER stress activates the NLRP3 inflammasome in microglial cells leading to the release of IL-1β. Furthermore, we showed that ER stress increases the production of ROS, which might act as an intermediate step between loss of ER proteostasis and inflammasome activation. Finally, we provided evidence that microglia cell survival is significantly compromised in response to ER stress. Discussion: These data support that chronic induction of an ER stress response in microglia due to the accumulation of misfolded proteins in the ER lumen, which is characteristic of several neurodegenerative disorders, is followed by ROS generation and activation of the NLRP3 inflammasome. Prolonged ER stress, through several signaling pathways that trigger cell death mechanisms, decreases the viability of microglia cells. However, it remains to be determined whether NLRP3 activation under stress conditions is dependent from ROS accumulation in this cell type. Conclusion: We provide evidence for a causal link between loss of proteostasis due to ER stress and inflammasome activation in microglia, a mechanism that might be implicated in neuroinflammation in protein misfolding neurodegenerative diseases. |
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| Autores principais: | Dias, Rafael Azevedo |
| Assunto: | Sistema nervoso central Stresse Doenças neurodegenerativas |
| Ano: | 2015 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Coimbra |
| Idioma: | inglês |
| Origem: | Estudo Geral - Universidade de Coimbra |
| Resumo: | Introduction: Microglial cells are the resident immune cells of the Central Nervous System (CNS) intervening in adaptive immune responses by activating the inflammasome, which converts pro-IL-1β to its active form in response to diverse stimuli such as endoplasmic reticulum stress (ER stress) that is induced by the overload of misfolded protein in the ER lumen. Both ER stress and activation of inflammasome have been implicated in the pathogenesis of neurodegenerative diseases, namely in Alzheimer’s disease (AD). However, the relationship between changes in ER proteostasis and neuroinflammation is still unclear. In this work we studied the involvement of ER stress in activation of the NLRP3 inflammasome in microglia. Methods: ER stress was induced in the microglia cell line BV2 with brefeldin A (BFA). Using Western blot, MTT, Amplex Red and ELISA assays, the levels of ER stress markers, cell viability, inflammasome activation and generation of reactive oxygen species (ROS) were evaluated. Results: We demonstrated that ER stress activates the NLRP3 inflammasome in microglial cells leading to the release of IL-1β. Furthermore, we showed that ER stress increases the production of ROS, which might act as an intermediate step between loss of ER proteostasis and inflammasome activation. Finally, we provided evidence that microglia cell survival is significantly compromised in response to ER stress. Discussion: These data support that chronic induction of an ER stress response in microglia due to the accumulation of misfolded proteins in the ER lumen, which is characteristic of several neurodegenerative disorders, is followed by ROS generation and activation of the NLRP3 inflammasome. Prolonged ER stress, through several signaling pathways that trigger cell death mechanisms, decreases the viability of microglia cells. However, it remains to be determined whether NLRP3 activation under stress conditions is dependent from ROS accumulation in this cell type. Conclusion: We provide evidence for a causal link between loss of proteostasis due to ER stress and inflammasome activation in microglia, a mechanism that might be implicated in neuroinflammation in protein misfolding neurodegenerative diseases. |
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