RESUMO
Sustained smouldering, or low-grade activation, of myeloid cells is a common hallmark of several chronic neurological diseases, including multiple sclerosis1. Distinct metabolic and mitochondrial features guide the activation and the diverse functional states of myeloid cells2. However, how these metabolic features act to perpetuate inflammation of the central nervous system is unclear. Here, using a multiomics approach, we identify a molecular signature that sustains the activation of microglia through mitochondrial complex I activity driving reverse electron transport and the production of reactive oxygen species. Mechanistically, blocking complex I in pro-inflammatory microglia protects the central nervous system against neurotoxic damage and improves functional outcomes in an animal disease model in vivo. Complex I activity in microglia is a potential therapeutic target to foster neuroprotection in chronic inflammatory disorders of the central nervous system3.
Assuntos
Complexo I de Transporte de Elétrons , Inflamação , Microglia , Doenças Neuroinflamatórias , Animais , Feminino , Humanos , Masculino , Camundongos , Sistema Nervoso Central/efeitos dos fármacos , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/patologia , Modelos Animais de Doenças , Transporte de Elétrons/efeitos dos fármacos , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Complexo I de Transporte de Elétrons/metabolismo , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Inflamação/patologia , Microglia/efeitos dos fármacos , Microglia/metabolismo , Microglia/patologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Multiômica , Células Mieloides/metabolismo , Células Mieloides/patologia , Doenças Neuroinflamatórias/tratamento farmacológico , Doenças Neuroinflamatórias/metabolismo , Doenças Neuroinflamatórias/patologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
AIM: Constitutive genetic deletion of the adaptor protein p66(Shc) was shown to protect from ischaemia/reperfusion injury. Here, we aimed at understanding the molecular mechanisms underlying this effect in stroke and studied p66(Shc) gene regulation in human ischaemic stroke. METHODS AND RESULTS: Ischaemia/reperfusion brain injury was induced by performing a transient middle cerebral artery occlusion surgery on wild-type mice. After the ischaemic episode and upon reperfusion, small interfering RNA targeting p66(Shc) was injected intravenously. We observed that post-ischaemic p66(Shc) knockdown preserved blood-brain barrier integrity that resulted in improved stroke outcome, as identified by smaller lesion volumes, decreased neurological deficits, and increased survival. Experiments on primary human brain microvascular endothelial cells demonstrated that silencing of the adaptor protein p66(Shc) preserves claudin-5 protein levels during hypoxia/reoxygenation by reducing nicotinamide adenine dinucleotide phosphate oxidase activity and reactive oxygen species production. Further, we found that in peripheral blood monocytes of acute ischaemic stroke patients p66(Shc) gene expression is transiently increased and that this increase correlates with short-term neurological outcome. CONCLUSION: Post-ischaemic silencing of p66(Shc) upon reperfusion improves stroke outcome in mice while the expression of p66(Shc) gene correlates with short-term outcome in patients with ischaemic stroke.
Assuntos
Lesões Encefálicas/prevenção & controle , Inativação Gênica/fisiologia , Traumatismo por Reperfusão/prevenção & controle , Proteínas Adaptadoras da Sinalização Shc/genética , Acidente Vascular Cerebral/prevenção & controle , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Animais , Barreira Hematoencefálica/fisiologia , Estudos de Casos e Controles , Células Cultivadas , Claudina-5/efeitos dos fármacos , Células Endoteliais/fisiologia , Feminino , Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Infarto da Artéria Cerebral Média , Pós-Condicionamento Isquêmico/métodos , Masculino , Camundongos Endogâmicos C57BL , Microcirculação/fisiologia , Pessoa de Meia-Idade , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/farmacologia , Espécies Reativas de Oxigênio/farmacologia , Proteínas Adaptadoras da Sinalização Shc/fisiologia , Proteína 1 de Transformação que Contém Domínio 2 de Homologia de Src , Resultado do TratamentoRESUMO
Sustained smouldering, or low grade, activation of myeloid cells is a common hallmark of several chronic neurological diseases, including multiple sclerosis (MS) 1 . Distinct metabolic and mitochondrial features guide the activation and the diverse functional states of myeloid cells 2 . However, how these metabolic features act to perpetuate neuroinflammation is currently unknown. Using a multiomics approach, we identified a new molecular signature that perpetuates the activation of myeloid cells through mitochondrial complex II (CII) and I (CI) activity driving reverse electron transport (RET) and the production of reactive oxygen species (ROS). Blocking RET in pro-inflammatory myeloid cells protected the central nervous system (CNS) against neurotoxic damage and improved functional outcomes in animal disease models in vivo . Our data show that RET in myeloid cells is a potential new therapeutic target to foster neuroprotection in smouldering inflammatory CNS disorders 3 .