The potassium channel KCa3.1 constitutes a pharmacological target for neuroinflammation associated with ischemia/reperfusion stroke
The potassium channel KCa3.1 constitutes a pharmacological target for neuroinflammation associated with ischemia/reperfusion stroke
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DOI：
10.1177/0271678x15611434
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发表时间：
2016-12-01
影响因子：
6.3
通讯作者：
Wulff, Heike
中科院分区：
文献类型：
--
作者：
Chen, Yi-Je;Nguyen, Hai M.;Wulff, Heike
活化的小胶质细胞/巨噬细胞在缺血性卒中的继发性炎症损伤中起重要作用。培养的新生儿小胶质细胞表达K+通道Kv1.3和KCa3.1，据报道这两种通道均参与小胶质细胞介导的神经元杀伤、氧化爆发和细胞因子产生。然而，这是值得怀疑的新生儿文化是否准确地反映了激活的小胶质细胞在成人大脑中的K+通道的表达。我们在此对小鼠进行大脑中动脉闭塞，再灌注8天，然后用膜片钳急性分离小胶质细胞/巨噬细胞。梗死区的小胶质细胞比非梗死对照脑的小胶质细胞具有更高的K+电流密度，其生物物理和药理学特性为Kv1.3、KCa3.1和Kir2.1。同样，对人类梗死的免疫组织化学显示出强烈的Kv1.3和KCa3.1免疫反应性的活化小胶质细胞/巨噬细胞。接下来，我们研究了KCa3.1基因缺失和药物阻断对可逆性大脑中动脉闭塞的影响。用KCa3.1阻断剂TRAM-34治疗的KCa3.1（-/-）小鼠和野生型小鼠在大脑中动脉闭塞后第8天表现出显著更小的梗死面积和改善的神经功能缺损。两种操作都降低了小胶质细胞/巨噬细胞活化和脑细胞因子水平。我们的研究结果表明KCa 3.1作为缺血性卒中的药理学靶点。潜在的临床相关性是，KCa 3.1阻断在损伤后12小时开始时仍然有效。
Activated microglia/macrophages significantly contribute to the secondary inflammatory damage in ischemic stroke. Cultured neonatal microglia express the K+ channels Kv1.3 and KCa3.1, both of which have been reported to be involved in microglia-mediated neuronal killing, oxidative burst and cytokine production. However, it is questionable whether neonatal cultures accurately reflect the K+ channel expression of activated microglia in the adult brain. We here subjected mice to middle cerebral artery occlusion with eight days of reperfusion and patch-clamped acutely isolated microglia/macrophages. Microglia from the infarcted area exhibited higher densities of K+ currents with the biophysical and pharmacological properties of Kv1.3, KCa3.1 and Kir2.1 than microglia from non-infarcted control brains. Similarly, immunohistochemistry on human infarcts showed strong Kv1.3 and KCa3.1 immunoreactivity on activated microglia/macrophages. We next investigated the effect of genetic deletion and pharmacological blockade of KCa3.1 in reversible middle cerebral artery occlusion. KCa3.1(-/-) mice and wild-type mice treated with the KCa3.1 blocker TRAM-34 exhibited significantly smaller infarct areas on day-8 after middle cerebral artery occlusion and improved neurological deficit. Both manipulations reduced microglia/macrophage activation and brain cytokine levels. Our findings suggest KCa3.1 as a pharmacological target for ischemic stroke. Of potential, clinical relevance is that KCa3.1 blockade is still effective when initiated 12 h after the insult.