Xinjiang Medical University, School of Basic Medical Science, Urumqi 830017, China.
Department of Pathology, The First Affiliated Hospital of Xinjiang Medical University, Xinjiang, China.
Int Immunopharmacol. 2024 Dec 25;143(Pt 2):113468. doi: 10.1016/j.intimp.2024.113468. Epub 2024 Oct 26.
Diacetylmorphine (DA) is widely implicated in neuronal injury; however, the underlying mechanisms remain unclear. We investigated the role of iron metamorphosis in DA-induced neurotoxicity using Sprague-Dawley rats and PC12 and SH-SY5Y cells. Tandem mass tag proteomics analysis showed that the upregulation of protein kinase C delta (PKCδ) and iron metabolism-related protein transferrin receptor (TFRC) significantly the enriched iron metabolism pathway. Subsequent experiments showed that DA exposure significantly upregulated PKCδ in PC12 cells, which increased the nuclear translocation of specificity protein 1 (SP1), and the intracellular free iron and lipid peroxide levels. In addition, silencing of PKCδ in rats improved behaviour and restored the expression level of glutathione peroxidase 4 (GPX4). In addition, DA exposure activated mitochondrial autophagy in PC12 cells, leading to a decrease in the mitochondrial membrane potential, accumulation of reactive oxygen species (ROS), elevation of LC3 (which plays a key role in autophagy), and a decrease in p62 expression. Following the inhibition of autophagy, the mitochondrial membrane potential and ROS were restored, as was the expression of voltage-dependent anion channel 1 (VDAC1) and GPX4. In conclusion, the present study suggests that PKCδ regulates SP1, further exacerbating DA-induced neuronal ferroptosis. Therefore, inhibition of PKCδ and mitochondrial autophagy or ferroptosis may be a key therapeutic target to ameliorate neurotoxicity following DA exposure.
二乙酰吗啡（DA）广泛参与神经元损伤；然而，其潜在机制仍不清楚。我们使用 Sprague-Dawley 大鼠和 PC12 及 SH-SY5Y 细胞研究了铁代谢变化在 DA 诱导的神经毒性中的作用。串联质量标签蛋白质组学分析显示，蛋白激酶 C 三角洲（PKCδ）和铁代谢相关蛋白转铁蛋白受体（TFRC）的上调显著富集了铁代谢途径。随后的实验表明，DA 暴露显著上调了 PC12 细胞中的 PKCδ，增加了特异性蛋白 1（SP1）的核易位，以及细胞内游离铁和脂质过氧化物水平。此外，大鼠中 PKCδ 的沉默改善了行为，并恢复了谷胱甘肽过氧化物酶 4（GPX4）的表达水平。此外，DA 暴露激活了 PC12 细胞中的线粒体自噬，导致线粒体膜电位下降，活性氧（ROS）积累，LC3（自噬的关键作用）升高，以及 p62 表达下降。自噬抑制后，线粒体膜电位和 ROS 得到恢复，电压依赖性阴离子通道 1（VDAC1）和 GPX4 的表达也得到恢复。综上所述，本研究表明 PKCδ 调节 SP1，进一步加重了 DA 诱导的神经元铁死亡。因此，抑制 PKCδ 和线粒体自噬或铁死亡可能是改善 DA 暴露后神经毒性的关键治疗靶点。
