Cerebral ischemia-reperfusion (I/R) can trigger neuronal death through several biologically plausible pathways, but its underlying neurobiological mechanisms remain unclear. In this study, we tested whether hyperpolarization-activated cyclic nucleotide-gated channel 1 (HCN1) is altered in I/R that contributes to neuron damage and further clarified the mechanisms underlying this process. Cerebral I/R injury was induced by middle cerebral artery occlusion (MCAO) surgery followed by reperfusion in rats or simulated by oxygen-glucose deprivation/reoxygenation (OGD/R) in cultured cell. After reperfusion, the mRNA and protein levels of HCN1 were tested by RT-PCR and Western blot (WB). The histone deacetylases 4 (HDAC4) shuttling and the nuclear neuron-restrictive silencer factor (NRSF) expression were evaluated by WB and immunohistochemistry. Our data showed that I/R caused a strong decrease of HCN1 subunit in both hippocampus and cortex of rat. Additionally, the nuclear expression of HDAC4 and NRSF were significantly increased. In vitro OGD/R model, the gathering of HDAC4 and NRSF to nuclei was further confirmed. Valproic acid (VPA), a HDAC4 inhibitor, could reverse the decreased HCN1 and protect neuron damage from OGD/R injury. Collectively, these results demonstrated that I/R cause a decrease of HCN1 expression via enhancing nuclear HDAC4-NRSF gathering and might contribute to neuron damage.

中文翻译：

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脑缺血再灌注通过增强导致神经元损伤的核 NRSF-HDAC4 聚集导致 HCN1 表达下调。

脑缺血再灌注 (I/R) 可以通过几种生物学上合理的途径引发神经元死亡，但其潜在的神经生物学机制仍不清楚。在这项研究中，我们测试了超极化激活的环核苷酸门控通道 1 (HCN1) 是否在 I/R 中发生改变，从而导致神经元损伤，并进一步阐明了这一过程的潜在机制。大脑 I/R 损伤是通过大脑中动脉闭塞 (MCAO) 手术诱导大鼠再灌注或在培养细胞中通过氧-葡萄糖剥夺/复氧 (OGD/R) 模拟的。再灌注后，通过RT-PCR和蛋白质印迹（WB）检测HCN1的mRNA和蛋白水平。组蛋白去乙酰化酶 4 (HDAC4) 穿梭和核神经元限制性沉默因子 (NRSF) 表达通过 WB 和免疫组织化学进行评估。我们的数据显示 I/R 导致大鼠海马和皮质中 HCN1 亚基的强烈减少。此外，HDAC4 和 NRSF 的核表达显着增加。在体外OGD/R模型中，进一步证实了HDAC4和NRSF向细胞核的聚集。丙戊酸 (VPA) 是一种 HDAC4 抑制剂，可以逆转 HCN1 减少并保护神经元免受 OGD/R 损伤。总的来说，这些结果表明 I/R 通过增强核 HDAC4-NRSF 的聚集导致 HCN1 表达降低，并可能导致神经元损伤。一种 HDAC4 抑制剂，可以逆转降低的 HCN1 并保护神经元免受 OGD/R 损伤。总的来说，这些结果表明 I/R 通过增强核 HDAC4-NRSF 的聚集导致 HCN1 表达降低，并可能导致神经元损伤。一种 HDAC4 抑制剂，可以逆转降低的 HCN1 并保护神经元免受 OGD/R 损伤。总的来说，这些结果表明 I/R 通过增强核 HDAC4-NRSF 的聚集导致 HCN1 表达降低，并可能导致神经元损伤。