School of Pharmacy, Anhui Medical University, 81 Meishan Road, Hefei, 230032, China.
Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, 720 Westview Drive, Atlanta, GA, 30310, USA.
Mol Neurobiol. 2020 Nov;57(11):4754-4766. doi: 10.1007/s12035-020-02056-4. Epub 2020 Aug 11.
Tissue acidosis is a common feature in many pathological conditions. Activation of acid-sensing ion channel 1a (ASIC1a) plays a key role in acidosis-mediated neurotoxicity. Protein kinase C (PKC) activity has been proved to be associated with many physiological processes and pathological conditions; however, whether PKC activation regulates ASIC1a protein expression and channel function remains ill defined. In this study, we demonstrated that treatment with phorbol 12-myristate 13-acetate (PMA, a PKC activator) for 6 h significantly increased ASIC1a protein expression and ASIC currents in NS20Y cells, a neuronal cell line, and in primary cultured mouse cortical neurons. In contrast, treatment with Calphostin C (a nonselective PKC inhibitor) for 6 h or longer decreased ASIC1a protein expression and ASIC currents. Similar to Calphostin C, PKC α and βI inhibitor Go6976 exposure also reduced ASIC1a protein expression. The reduction in ASIC1a protein expression by PKC inhibition involves a change in ASIC1a protein degradation, which is mediated by ubiquitin-proteasome system (UPS)-dependent degradation pathway. In addition, we showed that PKC regulation of ASIC1a protein expression involves NF-κB signaling pathway. Consistent with their effects on ASIC1a protein expression and channel function, PKC inhibition protected NS20Y cells against acidosis-induced cytotoxicity, while PKC activation potentiated acidosis-induced cells injury. Together, these results indicate that ASIC1a protein expression and channel function are closely regulated by the activity of protein kinase C and its downstream signaling pathway(s).
组织酸中毒是许多病理情况下的共同特征。酸感应离子通道 1a（ASIC1a）的激活在酸中毒介导的神经毒性中起着关键作用。蛋白激酶 C（PKC）的活性已被证明与许多生理过程和病理条件有关；然而，PKC 激活是否调节 ASIC1a 蛋白表达和通道功能仍未明确。在这项研究中，我们证明了用佛波醇 12-肉豆蔻酸 13-醋酸酯（PMA，PKC 激活剂）处理 6 小时可显著增加 NS20Y 细胞（神经元细胞系）和原代培养的小鼠皮质神经元中的 ASIC1a 蛋白表达和 ASIC 电流。相比之下，用 Calphostin C（一种非选择性 PKC 抑制剂）处理 6 小时或更长时间会降低 ASIC1a 蛋白表达和 ASIC 电流。与 Calphostin C 相似，PKCα和βI 抑制剂 Go6976 的暴露也降低了 ASIC1a 蛋白表达。PKC 抑制导致的 ASIC1a 蛋白表达减少涉及 ASIC1a 蛋白降解的变化，这是由泛素-蛋白酶体系统（UPS）依赖性降解途径介导的。此外，我们表明 PKC 调节 ASIC1a 蛋白表达涉及 NF-κB 信号通路。与它们对 ASIC1a 蛋白表达和通道功能的影响一致，PKC 抑制可保护 NS20Y 细胞免受酸中毒诱导的细胞毒性，而 PKC 激活则增强了酸中毒诱导的细胞损伤。总之，这些结果表明 ASIC1a 蛋白表达和通道功能受到蛋白激酶 C 及其下游信号通路的活性的密切调节。
