Department of Pharmaceutical Pharmacology, School of Clinical Pharmacy, College of Pharmaceutical Sciences, Matsuyama University, 4-2 Bunkyo-cho, Matsuyama 790-8578, Ehime, Japan.
Brain Res. 2013 Nov 6;1537:340-9. doi: 10.1016/j.brainres.2013.09.024. Epub 2013 Sep 23.
Two channel proteins, inwardly rectifying potassium channel 4.1 (Kir4.1) and water channel aquaporin-4 (AQP4), were recently identified as targets of an autoantibody response in patients with multiple sclerosis and neuromyelitis optica, respectively. In the present study, we examined the expression patterns of Kir4.1 and AQP4 in a mouse model of demyelination induced by cuprizone, a copper chelator. Demyelination was confirmed by immunohistochemistry using an anti-proteolipid protein antibody in various brain regions, including the corpus callosum, of cuprizone-fed mice. Activation of microglial and astroglial cells was also confirmed by immunohistochemistry, using an anti-ionized calcium binding adapter molecule and a glial fibrillary acidic protein antibody. Western blot analysis revealed the induction of Kir4.1 protein, but not AQP4, in the cortex of cuprizone-fed mice. Immunohistochemical analysis confirmed the Kir4.1 protein induction in microvessels of the cerebral cortex. Real-time polymerase chain reaction analysis revealed that mRNA levels of Kir4.1 and AQP4 in the cortex did not change during cuprizone administration. These findings suggest that enhanced accumulation of Kir4.1 protein in the brain with an inflammatory condition facilitates the autoantibody formation against Kir4.1 in patients with multiple sclerosis.
两种通道蛋白，内向整流钾通道 4.1（Kir4.1）和水通道蛋白 aquaporin-4（AQP4），最近分别被确定为多发性硬化症和视神经脊髓炎患者自身抗体反应的靶标。在本研究中，我们在由铜螯合剂铜吡咯啉诱导的脱髓鞘小鼠模型中检查了 Kir4.1 和 AQP4 的表达模式。用抗髓磷脂蛋白抗体通过免疫组织化学在包括胼胝体在内的各种脑区确认脱髓鞘。用抗离子钙结合衔接分子和胶质纤维酸性蛋白抗体的免疫组织化学也证实了小胶质细胞和星形胶质细胞的激活。Western blot 分析显示，在铜吡咯啉喂养的小鼠的皮质中诱导了 Kir4.1 蛋白，但不诱导 AQP4。免疫组织化学分析证实了大脑皮质中小血管 Kir4.1 蛋白的诱导。实时聚合酶链反应分析显示，在铜吡咯啉给药期间，皮质中 Kir4.1 和 AQP4 的 mRNA 水平没有变化。这些发现表明，在炎症状态下大脑中 Kir4.1 蛋白的积累增加有助于多发性硬化症患者中针对 Kir4.1 的自身抗体形成。
