Center for Neuroscience and Cell Biology, University of Coimbra (CNC-UC), Portugal; Center for Innovation in Biomedicine and Biotechnology (CIBB), Portugal; Institute for Interdisciplinary Research (III), University of Coimbra, Portugal.
Center for Neuroscience and Cell Biology, University of Coimbra (CNC-UC), Portugal; Center for Innovation in Biomedicine and Biotechnology (CIBB), Portugal; Institute of Physiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
Free Radic Biol Med. 2024 Aug 1;220:192-206. doi: 10.1016/j.freeradbiomed.2024.05.011. Epub 2024 May 9.
Enhanced formation of advanced glycation end products (AGEs) is a pivotal factor in diabetes pathophysiology, increasing the risk of diabetic complications. Nε-carboxy-methyl-lysine (CML) is one of the most relevant AGEs found in several tissues including the peripheral blood of diabetic subjects. Despite recognizing diabetes as a risk factor for neurodegenerative diseases and the documented role of mitochondrial abnormalities in this connection, the impact of CML on neuronal mitochondria and its contribution to diabetes-related neurodegeneration remain uncertain. Here, we evaluated the effects of CML in differentiated SH-SY5Y human neuroblastoma cells. Due to the association between mitochondrial dysfunction and increased production of reactive oxygen species (ROS), the possible protective effects of MitoTempo, a mitochondria-targeted antioxidant, were also evaluated. Several parameters were assessed namely cells viability, mitochondrial respiration and membrane potential, ATP and ROS production, Ca levels, mitochondrial biogenesis and dynamics, mito/autophagy, endoplasmic reticulum (ER) stress and amyloidogenic and synaptic integrity markers. CML caused pronounced mitochondrial defects characterized by a significant decrease in mitochondrial respiration, membrane potential, and ATP production and an increase in ROS production. An accumulation of individual mitochondria associated with disrupted mitochondrial networks was also observed. Furthermore, CML caused mitochondrial fusion and a decrease in mitochondrial mass and induced ER stress associated with altered unfolded protein response and Ca dyshomeostasis. Moreover, CML increased the protein levels of β-secretase-1 and amyloid precursor protein, key proteins involved in Alzheimer's Disease pathophysiology. All these effects contributed to the decline in neuronal cells viability. Notable, MitoTempo was able to counteract most of CML-mediated mitochondrial defects and neuronal cells injury and death. Overall, these findings suggest that CML induces pronounced defects in neuronal mitochondria and ER stress, predisposing to neurodegenerative events. More, our observations suggest that MitoTempo holds therapeutic promise in mitigating CML-induced mitochondrial imbalance and neuronal damage and death.
糖基化终产物（AGEs）的形成增加是糖尿病病理生理学的一个关键因素，增加了糖尿病并发症的风险。Nε-羧甲基赖氨酸（CML）是在包括糖尿病患者外周血在内的几种组织中发现的最相关的 AGEs 之一。尽管认识到糖尿病是神经退行性疾病的一个危险因素，并且线粒体异常在这方面的作用已有记载，但 CML 对神经元线粒体的影响及其对与糖尿病相关的神经退行性变的贡献仍不确定。在这里，我们评估了 CML 在分化的 SH-SY5Y 人神经母细胞瘤细胞中的作用。由于线粒体功能障碍与活性氧（ROS）产生增加之间存在关联，因此还评估了线粒体靶向抗氧化剂 MitoTempo 的可能保护作用。评估了几个参数，即细胞活力、线粒体呼吸和膜电位、ATP 和 ROS 产生、Ca 水平、线粒体生物发生和动力学、线粒体自噬、内质网（ER）应激和淀粉样和突触完整性标志物。CML 引起明显的线粒体缺陷，表现为线粒体呼吸、膜电位和 ATP 产生显著下降，ROS 产生增加。还观察到与破坏的线粒体网络相关的单个线粒体的积累。此外，CML 导致线粒体融合和线粒体质量减少，并诱导与未折叠蛋白反应改变和 Ca 动态失衡相关的 ER 应激。此外，CML 增加了β-分泌酶-1 和淀粉样前体蛋白的蛋白水平，这是阿尔茨海默病病理生理学的关键蛋白。所有这些作用都导致神经元细胞活力下降。值得注意的是，MitoTempo 能够抵消 CML 介导的大部分线粒体缺陷和神经元细胞损伤和死亡。总体而言，这些发现表明 CML 诱导神经元线粒体和 ER 应激明显缺陷，易发生神经退行性事件。更重要的是，我们的观察结果表明，MitoTempo 具有治疗潜力，可以减轻 CML 诱导的线粒体失衡和神经元损伤和死亡。
