Abstract P795: Activating Transcription Factor 3 Improves Stroke Recovery Through Reduction of Neuronal Damage and Neuroinflammation
Background and Purpose: Activating transcription factor 3 (ATF3), a member of the ATF/CREB family, is upregulated in the early phase of various stresses including ischemic stroke. The role of ATF3 in ischemic stroke injury has not been fully elucidated. Hypothesis: ATF3 improves stroke outcomes through reduction of neuronal damage and neuroinflammation. Methods: Permanent distal middle cerebral artery occlusion (pMCAO) was performed in 8-week-old male and female C57BL/6J (WT) and ATF3 knockout (ATF3 -/- ) mice. The sensorimotor functions were analyzed 3 days after pMCAO through adhesive removal and corner tests. Infarct volumes and injured neurons were quantified on Nissl stained and Fluoro-Jade C (FJC) stained sections. The cell-specific expression of ATF3 was analyzed by co-staining ATF3 antibody with antibodies specific to NeuN (Neuron), CD68 (microglia/macrophage) and GFAP (astrocyte). The expression of ATF3 in injured neurons was analyzed by ATF3 and FJC double labeling. Results: ATF3 expression was detected exclusively in neurons in the infarct area 1 day after pMCAO. There were a few ATF3 + CD68 + microglia/macrophages at the peri-infarct regions 2 and 3 days after pMCAO. Almost all FJC + neurons were ATF3 positive. No ATF3 expression was detected in astrocytes. Compared to WT mice, ATF3 -/- mice took longer time to remove the adhesive from their right paws (p<0.001) in adhesive removal test and more left turns in corner test (p<0.001) 3 days after pMCAO. ATF3 -/- mice also had a larger infarct volume (p = 0.014), more FJC + neurons (p=0.002) and CD68 + microglia/macrophages (p=0.003) in the peri-infarct regions than WT mice. Conclusions: Deletion of ATF3 exacerbates neuronal injury, neuroinflammation, and sensorimotor dysfunction in stroke mice, suggesting that upregulation of ATF3 at early stage of stroke improves ischemic stroke recovery through reduction of neuronal damage and neuroinflammation.