Microglia‐mediated inflammation exerts adverse effects in ischemic stroke and in neurodegenerative disorders such as Alzheimer's disease (AD). Expression of the voltage‐gated potassium channel Kv1.3 is required for microglia activation. Both genetic deletion and pharmacological inhibition of Kv1.3 are effective in reducing microglia activation and the associated inflammatory responses, as well as in improving neurological outcomes in animal models of AD and ischemic stroke. Here we sought to elucidate the molecular mechanisms underlying the therapeutic effects of Kv1.3 inhibition, which remain incompletely understood. Using a combination of whole‐cell voltage‐clamp electrophysiology and quantitative PCR (qPCR), we first characterized a stimulus‐dependent differential expression pattern for Kv1.3 and P2X4, a major ATP‐gated cationic channel, both in vitro and in vivo. We then demonstrated by whole‐cell current‐clamp experiments that Kv1.3 channels contribute not only to setting the resting membrane potential but also play an important role in counteracting excessive membrane potential changes evoked by depolarizing current injections. Similarly, the presence of Kv1.3 channels renders microglia more resistant to depolarization produced by ATP‐mediated P2X4 receptor activation. Inhibiting Kv1.3 channels with ShK‐223 completely nullified the ability of Kv1.3 to normalize membrane potential changes, resulting in excessive depolarization and reduced calcium transients through P2X4 receptors. Our report thus links Kv1.3 function to P2X4 receptor‐mediated signaling as one of the underlying mechanisms by which Kv1.3 blockade reduces microglia‐mediated inflammation. While we could confirm previously reported differences between males and females in microglial P2X4 expression, microglial Kv1.3 expression exhibited no gender differences in vitro or in vivo.

中文翻译：

---

Kv1.3 调节 P2X4 介导的小胶质细胞钙进入引起的膜电位变化的生物物理基础。

小胶质细胞介导的炎症对缺血性中风和阿尔茨海默病 (AD) 等神经退行性疾病有不利影响。小胶质细胞激活需要电压门控钾通道 Kv1.3 的表达。Kv1.3 的基因缺失和药理学抑制均能有效减少小胶质细胞活化和相关炎症反应，以及改善 AD 和缺血性中风动物模型的神经系统结果。在这里，我们试图阐明 Kv1.3 抑制治疗效果的分子机制，这些机制仍未完全了解。结合全细胞电压钳电生理学和定量 PCR (qPCR)，我们首先表征了 Kv1.3 和 P2X4（一种主要的 ATP 门控阳离子通道）的刺激依赖性差异表达模式，在体外和体内。然后，我们通过全细胞电流钳实验证明，Kv1.3 通道不仅有助于设定静息膜电位，而且在抵消去极化电流注入引起的过度膜电位变化方面发挥重要作用。同样，Kv1.3 通道的存在使小胶质细胞更能抵抗由 ATP 介导的 P2X4 受体激活产生的去极化。用 ShK-223 抑制 Kv1.3 通道完全消除了 Kv1.3 使膜电位变化正常化的能力，导致过度去极化和通过 P2X4 受体的钙瞬变减少。因此，我们的报告将 Kv1.3 功能与 P2X4 受体介导的信号传导联系起来，这是 Kv1.3 阻断减少小胶质细胞介导炎症的潜在机制之一。