Department of Physiological Sciences, Stellenbosch University, Stellenbosch 7600, South Africa.
Department of Electric and Electronic Engineering, Stellenbosch University, Stellenbosch 7600, South Africa.
Cells. 2023 Jun 27;12(13):1726. doi: 10.3390/cells12131726.
Memantine is an FDA-approved, non-competitive NMDA-receptor antagonist that has been shown to have mitochondrial protective effects, improve cell viability and enhance clearance of Aβ peptide. Currently, there are uncertainties regarding the precise molecular targets as well as the most favourable treatment concentrations of memantine. Here, we made use of an imaging-based approach to investigate the concentration-dependent effects of memantine on mitochondrial fission and fusion dynamics, autophagy and mitochondrial quality control using a neuronal model of CCCP-induced mitochondrial injury so as to better unpack how memantine aids in promoting neuronal health. GT1-7 murine hypothalamic cells were cultured under standard conditions, treated with a relatively high and low concentration (100 µM and 50 µM) of memantine for 48 h. Images were acquired using a Zeiss 780 PS1 platform. Utilising the mitochondrial event localiser (MEL), we demonstrated clear concentration-dependent effects of memantine causing a protective response to mitochondrial injury. Both concentrations maintained the mitochondrial network volume whilst the low concentration caused an increase in mitochondrial number as well as increased fission and fusion events following CCCP-induced injury. Additionally, we made use of a customised Python-based image processing and analysis pipeline to quantitatively assess memantine-dependent changes in the autophagosomal and lysosomal compartments. Our results revealed that memantine elicits a differential, concentration-dependent effect on autophagy pathway intermediates. Intriguingly, low but not high concentrations of memantine lead to the induction of mitophagy. Taken together, our findings have shown that memantine is able to protect the mitochondrial network by preserving its volume upon mitochondrial injury with high concentrations of memantine inducing macroautophagy, whereas low concentrations lead to the induction of mitophagy.
美金刚是一种获得美国食品药品监督管理局批准的非竞争性 NMDA 受体拮抗剂，已被证明具有线粒体保护作用，可以提高细胞活力并增强 Aβ 肽的清除。目前，关于美金刚的确切分子靶点以及最有利的治疗浓度仍存在不确定性。在这里，我们利用基于成像的方法研究了美金刚对线粒体裂变和融合动力学、自噬以及线粒体质量控制的浓度依赖性影响，使用 CCCP 诱导的线粒体损伤的神经元模型，以更好地阐明美金刚如何有助于促进神经元健康。GT1-7 小鼠下丘脑细胞在标准条件下培养，用相对较高和较低浓度（100 μM 和 50 μM）的美金刚处理 48 小时。使用蔡司 780 PS1 平台获取图像。利用线粒体事件定位器（MEL），我们证明了美金刚的浓度依赖性作用，对线粒体损伤有保护作用。两种浓度都维持了线粒体网络体积，而低浓度导致线粒体数量增加，以及 CCCP 诱导损伤后裂变和融合事件增加。此外，我们还使用了一个基于 Python 的定制图像处理和分析管道，对美金刚依赖性自噬体和溶酶体腔室变化进行定量评估。我们的结果表明，美金刚对自噬途径中间产物产生了不同的、浓度依赖性的影响。有趣的是，低浓度但不是高浓度的美金刚会引发细胞自噬。总之，我们的研究结果表明，美金刚能够通过在高浓度美金刚诱导巨自噬时保持线粒体网络的体积来保护线粒体网络，而低浓度则会诱导细胞自噬。
