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.
Electron Transport Complex I , Inflammation , Microglia , Neuroinflammatory Diseases , Animals , Female , Humans , Male , Mice , Central Nervous System/drug effects , Central Nervous System/metabolism , Central Nervous System/pathology , Disease Models, Animal , Electron Transport/drug effects , Electron Transport Complex I/antagonists & inhibitors , Electron Transport Complex I/metabolism , Inflammation/drug therapy , Inflammation/metabolism , Inflammation/pathology , Microglia/drug effects , Microglia/metabolism , Microglia/pathology , Mitochondria/drug effects , Mitochondria/metabolism , Mitochondria/pathology , Multiomics , Myeloid Cells/metabolism , Myeloid Cells/pathology , Neuroinflammatory Diseases/drug therapy , Neuroinflammatory Diseases/metabolism , Neuroinflammatory Diseases/pathology , Reactive Oxygen Species/metabolism
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 .
