GLUT1-driven glycolytic reprogramming in microglia promotes neuroinflammation and cognitive deficits in sepsis-associated encephalopathy.

BACKGROUND

Sepsis-associated encephalopathy (SAE) is a severe neurological complication driven by microglial neuroinflammation. Proinflammatory microglial activation requires glycolytic reprogramming, but whether GLUT1 governs this process in SAE remains unclear.

METHODS

In vitro, LPS-stimulated BV2 microglia were transfected with siRNA targeting GLUT1 or GLUT3. Glucose uptake (2-NBDG), glycolytic flux (ECAR, lactate), mitochondrial respiration (OCR), glycolytic enzyme expression (HK2, PFKFB3, PKM2, LDHA), and inflammatory cytokine release were assessed. In vivo, SAE was induced in C57BL/6 mice by cecal ligation and puncture (CLP). Hippocampal GLUT1 knockdown was achieved via stereotactic lentivirus injection. Cognitive function, neuronal damage, neuroinflammation, cerebral lactate/ATP levels, and glycolytic protein expression were evaluated.

RESULTS

LPS significantly upregulated GLUT1, but not GLUT3, in BV2 cells. GLUT1 knockdown markedly suppressed LPS-enhanced glucose uptake, ECAR, lactate production, and expression of HK2, PFKFB3, PKM2, and LDHA, while restoring OCR and reducing TNF-α, IL-1β, and IL-6 secretion. GLUT3 knockdown showed no such effects. In SAE mice, hippocampal GLUT1 expression was increased. Hippocampal GLUT1 knockdown ameliorated cognitive deficits, attenuated hippocampal neuronal loss and Nissl body damage, reduced cerebral inflammatory cytokines and lactate, restored ATP content, and abrogated CLP-induced upregulation of glycolytic enzymes.

CONCLUSIONS

GLUT1 is a critical metabolic checkpoint driving microglial glycolytic reprogramming and proinflammatory activation in SAE. Targeted GLUT1 knockdown in microglia alleviates neuroinflammation and cognitive impairment in experimental SAE models. These findings provide a proof-of-concept that metabolic checkpoint targeting may counteract microglial pro-inflammatory activation.