Laboratory of Pharmacology, Kobe Pharmaceutical University, Kobe, Japan.
Department of Pharmacodynamics, Meiji Pharmaceutical University, Kiyose, Tokyo, Japan.
Glia. 2024 Dec;72(12):2231-2246. doi: 10.1002/glia.24609. Epub 2024 Aug 21.
Na-K-2Cl cotransporter-1 (NKCC1) is present in brain cells, including astrocytes. The expression of astrocytic NKCC1 increases in the acute phase of traumatic brain injury (TBI), which induces brain edema. Endothelin-1 (ET-1) is a factor that induces brain edema and regulates the expression of several pathology-related genes in astrocytes. In the present study, we investigated the effect of ET-1 on NKCC1 expression in astrocytes. ET-1 (100 nM)-treated cultured astrocytes showed increased NKCC1 mRNA and protein levels. The effect of ET-1 on NKCC1 expression in cultured astrocytes was reduced by BQ788 (1 μM), an ET antagonist, but not by FR139317 (1 μM), an ET antagonist. The involvement of ET-1 in NKCC1 expression in TBI was examined using a fluid percussion injury (FPI) mouse model that replicates the pathology of TBI with high reproducibility. Administration of BQ788 (15 nmol/day) decreased FPI-induced expressions of NKCC1 mRNA and protein, accompanied with a reduction of astrocytic activation. FPI-induced brain edema was attenuated by BQ788 and NKCC1 inhibitors (azosemide and bumetanide). ET-1-treated cultured astrocytes showed increased mRNA and protein expression of hypoxia-inducible factor-1α (HIF1α). Immunohistochemical observations of mouse cerebrum after FPI showed co-localization of HIF1α with GFAP-positive astrocytes. Increased HIF1α expression in the TBI model was reversed by BQ788. FM19G11 (an HIF inhibitor, 1 μM) and HIF1α siRNA suppressed ET-induced increase in NKCC1 expression in cultured astrocytes. These results indicate that ET-1 increases NKCC1 expression in astrocytes through the activation of HIF1α.
钠钾 2 氯协同转运蛋白-1（NKCC1）存在于脑细胞中，包括星形胶质细胞。创伤性脑损伤（TBI）急性期星形胶质细胞 NKCC1 的表达增加，导致脑水肿。内皮素-1（ET-1）是一种诱导脑水肿并调节星形胶质细胞中几种与病理相关基因表达的因子。在本研究中，我们研究了 ET-1 对星形胶质细胞 NKCC1 表达的影响。用 ET-1（100 nM）处理的培养星形胶质细胞显示 NKCC1 mRNA 和蛋白水平增加。ET 拮抗剂 BQ788（1 μM）而非 ET 拮抗剂 FR139317（1 μM）可降低 ET-1 对培养星形胶质细胞 NKCC1 表达的影响。使用流体冲击损伤（FPI）小鼠模型研究了 ET-1 在 TBI 中对 NKCC1 表达的影响，该模型可高度重现 TBI 的病理变化。给予 BQ788（15 nmol/天）可降低 FPI 诱导的 NKCC1 mRNA 和蛋白表达，同时减少星形胶质细胞活化。BQ788 和 NKCC1 抑制剂（氨苯蝶啶和布美他尼）可减轻 FPI 诱导的脑水肿。ET-1 处理的培养星形胶质细胞显示缺氧诱导因子-1α（HIF1α）的 mRNA 和蛋白表达增加。FPI 后小鼠大脑的免疫组织化学观察显示 HIF1α 与 GFAP 阳性星形胶质细胞共定位。BQ788 逆转了 TBI 模型中 HIF1α 的表达增加。FM19G11（HIF 抑制剂，1 μM）和 HIF1α siRNA 抑制 ET 诱导的培养星形胶质细胞中 NKCC1 表达增加。这些结果表明，ET-1 通过激活 HIF1α 增加星形胶质细胞中的 NKCC1 表达。
