Evaluating the neuroprotective effects of the novel Kv2.1 blocker Zj7923 against ischemic stroke in vitro and in vivo

Abstract

The voltage-dependent potassium channel Kv2.1 correlates closely to the regulation of neuronal excitability and cellular apoptosis. Ischemia or oxidative treatment were known to stimulate the surge of Kv2.1-mediated current to activate neuronal apoptosis pathways, while inhibiting excessive Kv2.1 K⁺ current efflux could reduce neuronal apoptosis and exhibit neuroprotective effects. Here, we found a novel Kv2.1 selective blocker Zj7923 and investigated whether it produces neuroprotective function after ischemic stroke animal model. We demonstrate that Zj7923 potently inhibits Kv2.1 current with an IC₅₀ of 0.12 μM. Zj7923 had no obvious effect on the activation process of Kv2.1 channels, but could significantly accelerate the inactivation process of Kv2.1 channels. The mutations at Y380 and K356 in the outer vestibule of Kv2.1 channels weakened the inhibitory effect of Zj7923, and the IC₅₀ value of Zj7923 on the mutation channels increased to 3.66 μM and 3.20 μM, respectively, indicating that the compound may act on the above two positions. Zj7923 could increase the spontaneous firing rate of normal hippocampal pyramidal neurons and ameliorate OGD-induced impairment of neuronal excitability. Kv2.1 channel inhibition by Zj7923 provides protection against DTDP-induced apoptosis and its mechanism might be related to the modulation of the expression of apoptosis-related proteins, such as Bcl-2, Bax and cleaved caspase-3 proteins. In vivo pharmacodynamics evaluation, intravenous administration of Zj7923 in rats following transient middle cerebral artery occlusion significantly reduced infarct volume and improved neurological deficits. Our results indicate that Zj7923 exerts a neuronal protection from cerebral ischemia in vitro and in vivo by inhibiting Kv2.1 current and validate the potential value of developing drugs targeting Kv2.1 for ischemic stroke.