Activation of oligodendrocyte precursor cells triggers cognitive dysfunction and synaptic defects in SAE

Sepsis-associated encephalopathy (SAE) is defined as a diffuse neurological dysfunction that occurs secondary to sepsis, in the absence of direct central nervous system infection, and is associated with high rates of incidence, mortality, and disability. Despite its clinical significance, the neuropathological mechanisms underlying SAE are not yet fully understood, making its pathogenesis a focal point of ongoing research. Oligodendrocyte precursor cells (OPCs), which are the most proliferative cell type within the central nervous system, primarily contribute to the generation of mature oligodendrocytes and are integral to myelination and the maintenance of myelin. Nevertheless, the role and pathological changes of OPCs during the acute phase of SAE remain inadequately characterized. This study illustrates that OPCs in the hippocampal CA1 region may undergo immune activation under SAE conditions, characterized by significantly elevated inflammatory transcription and phagocytic capacity. Additionally, activated OPCs in SAE mice may contribute to the synaptic pruning of neurons. By generating PDGFRa-Cre/ERT transgenic mice and conducting stereotactic injections of pAAV-EGFP-flex-DTA virus into the hippocampal CA1 region to selectively ablate OPCs, we observed a significant enhancement in cognitive function in SAE mice. This improvement is likely due to the alleviation of synaptic structural and functional impairments in neurons. Our findings indicate that OPCs play a critical role in the pathogenesis of SAE, highlighting their potential as a novel therapeutic target for this condition.