Development of a Novel Cofilin Inhibitor for the Treatment of Hemorrhagic Brain Injury

Intracerebral hemorrhage (ICH) is a devastating form of stroke with high mortality. Traditional treatments for ICH are primarily supportive, including blood pressure control, hemostasis, and rehabilitation. To date, no medical or surgical intervention has been proven successful. Most of the pharmacological therapies have failed to pro- vide favorable outcomes or reduce the mortality due to the complexity of the cellular mechanisms and diversity of signaling cascades involved after ICH. The multifacto- rial secondary injury induced by ICH requires a new therapeutic strategy targeting multiple pathways to lessen the impact of brain injury and improve patient survival. Our previous studies have proposed cofilin as a potential therapeutic drug target for ICH. After obtaining convincing results on the role of cofilin in brain pathol- ogy, we embarked on designing and synthesizing a first-in-class small molecule in- hibitor of cofilin, SZ-3 to effectively target multiple pathways to prevent neurological damage and decrease secondary complications after ICH. The potential binding and inhibiting activity of SZ-3 was tested on isolated actin by measuring the F-actin length subjected to cofilin. SZ-3 was able to decrease cofilin severing activity, which also suggested a reasonable affinity of the compound. SZ-3 treatment was found to attenuate microglial activation, suppress migration, and proliferation. Human mi- croglial cultures subjected to thrombin, as an experimental model for hemorrhagic stroke, treated with SZ-3 3h later showed a significant decrease in nitric oxide (NO), and tumor necrosis factor (TNF-α) production after LPS stimulation. Besides, the compound significantly increased phosphocofilin and decreased protein expression of protease-activated receptor-1 (PAR1) in thrombin-activated microglia. Furthermore, the compound showed a significant increase in cell viability, induced neuroprotection by significantly decreasing nuclear factor-kappa B (NF-kB), caspase-3, and high- temperature requirement (HtrA2) following ICH. Finally, SZ-3 showed promising neurobehavioral outcome in an in vivo model of ICH, which supports the future ex- tensive in vivo studies as a new lead compound for the treatment of hemorrhagic and ischemic strokes.