GCN2 reduces inflammation by p-eIF2α/ATF4 pathway after intracerebral hemorrhage in mice.

Intracerebral hemorrhage (ICH) is a common and severe neurological disorder, which is associated with high rates of mortality and morbidity. This study aimed to evaluate whether general control non-derepressible-2 (GCN2) stimulation ameliorated neuroinflammation after ICH. Male CD-1 mice were subjected to experimental ICH by infusion of bacterial collagenase. Post-ictus assessment included neurobehavioral tests, brain edema measurement, quantification of neutrophil infiltration and microglia activation, and measurement of TNF-α and IL-1β expression at 24h after ICH. Furthermore, we tested the long-term neurological improvement by GCN2 at 21 days after ICH. Our results showed that GCN2 improved neurological function and reduced brain edema at 24 and 72 h following experimental ICH in CD-1 mice in contrast to the vehicle administration alone. GCN2 was also found to decrease levels of IL-1β and TNF-α, and inhibit neutrophil infiltration activation. In addititon, GCN2 also alleviated long-term neurological impairment after ICH. However, inhibition of eIF2α or ATF4 abolished the protective effects of GCN2, indicating eIF2α/ATF4 signaling pathway as the downstream mediator of GCN2.