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

Abstract

Intracerebral hemorrhage (ICH) is a devastating form of stroke with high mortality and morbidity. 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 provide favorable outcomes or reduce the mortality possibly due to the complexity of the cellular mechanisms and diversity of signaling cascades involved after ICH. The multifactorial secondary injury induced by ICH requires a novel therapeutic strategy targeting multiple pathways in order to lessen the impact of brain injury and improve the patient survival. Our previous studies have demonstrated cofilin as a potential therapeutic drug target for ICH. In the current study, we embarked on designing and synthesizing a first-in-class small molecule inhibitor of cofilin to effectively target multiple pathways to prevent secondary complications after ICH. The potential binding and inhibiting concept of synthesized cofilin inhibitor, SZ-3 was tested on isolated actin by measuring the F-actin length after adding cofilin. SZ-3 was able to decrease cofilin severing activity which suggests a reasonable affinity of the compound. SZ-3 treatment of LPS activated microglia was found to attenuate microglial cell activation, suppress migration and proliferation. Human microglial (HMC3) cultures subjected to thrombin, as in vitro model for hemorrhage and treated with SZ-3 after 3h showed significant decrease in nitric oxide (NO), tumor necrosis factor (TNF-α) production in LPS-stimulated microglia. Also, the treatment with SZ-3 significantly increased phosphocofilin and decreased protein expression of protease-activated receptor-1 (PAR1) in thrombin-activated microglia. In addition, SZ-3 treated microglia showed a significant increase in cell viability by significantly decreasing nuclear factor-kappa B (NF-κB), caspase-3 and high-temperature requirement (HtrA2) Finally, SZ-3 treatment enhanced locomotor and neurobehavioral outcomes in an in vivo model of ICH. Together, our results support the idea of targeting cofilin to counter secondary injury following ICH.