Therapeutic targeting of microglial hexokinase-2 attenuates inflammasome activation and improves functional recovery after traumatic brain injury

Traumatic brain injury (TBI) initiates a secondary inflammatory cascade in which sustained microglial activation contributes to neurological dysfunction. Because inflammatory microglial states are accompanied by bioenergetic reconfiguration, modulation of metabolic regulators may provide a strategy to limit post-traumatic inflammation while preserving essential immune functions. Hexokinase-2 (HK2), a glycolytic enzyme with additional roles in mitochondrial and inflammatory signaling, regulates microglial activation in neurodegenerative conditions; however, its contribution to TBI remains unclear. We investigated HK2 in a mouse model of severe controlled cortical impact (CCI), characterized by extensive ipsilateral cortical damage and involvement of the underlying hippocampus. HK2 expression was assessed at 3, 7, and 15 days post-injury. The HK2 function was targeted pharmacologically with lonidamine (LND; 50 mg/kg, intraperitoneally), administered once daily for 7 days beginning 24 h after CCI, and genetically using a microglial-specific HK2-haplodeficient mouse to produce partial HK2 reduction in microglia. Cortical HK2 mRNA was increased by 3 days post-CCI and remained elevated through day 15, when increased HK2 immunoreactivity was detected in IBA1-positive cells. In vitro, LND restrained acute LPS-induced increases in glycolytic and oxidative activity, reduced total ATP production, and suppressed NF-κB reporter activity. LND also slowed proliferation of microglial-like BV2 cells without impairing uptake of labeled dead-cell cargo. In vivo, LND improved rotarod performance without altering general locomotor activity or spatial working-memory performance and reduced inflammasome-associated gene expression and ASC accumulation, with prominent effects in the hippocampus and hilus. Partial genetic reduction of microglial HK2 similarly improved motor performance after CCI, supporting a contribution of HK2 to post-traumatic dysfunction. Together, these findings identify HK2 as a regulator of microglial bioenergetic and inflammatory responses after severe TBI. Partial HK2 antagonism limits sustained post-traumatic inflammation and is associated with improved functional outcome, supporting further investigation of HK2 modulation as a therapeutic strategy for secondary brain injury.