Metabolic reprogramming in astrocytes prevents neuronal death through a UCHL1/PFKFB3/H4K8la positive feedback loop

Abstract

Astrocytic metabolic reprogramming is an adaptation of metabolic patterns to meet increased energy demands, although the role after spinal cord injury (SCI) remains unclear. Analysis of single-cell RNA sequencing (scRNA-seq) data identified an increase in astrocytic glycolysis, while PFKFB3, a key regulator of glycolytic flux, was significantly upregulated following SCI. Loss of PFKFB3 in astrocytes prohibited neuronal energy supply and enhanced neuronal ferroptosis in vitro and expanded infiltration of CD68⁺ macrophages/microglia, exacerbated neuronal loss, and hindered functional recovery in vivo after SCI. Mechanistically, deubiquitinase UCHL1 plays a crucial role in stabilizing and enhancing PFKFB3 expression by cleaving K48-linked ubiquitin chains. Genetic deletion of Uchl1 inhibited locomotor recovery after SCI by suppression of PFKFB3-induced glycolytic reprogramming in astrocytes. Furthermore, the UCHL1/PFKFB3 axis increased lactate production, leading to enhanced histone lactylation and subsequent transcription of Uchl1 and several genes related to glycolysis, suggesting a glycolysis/H4K8la/UCHL1 positive feedback loop. These findings help to clarify the role of the UCHL1/PFKFB3/H4K8la loop in modulation of astrocytic metabolic reprogramming and reveal a potential target for treatment of SCI.