Neuroscience Research Group, Medical Research Institute, Faculty of Medicine, University of Antioquia (UdeA), SIU Medellin, Medellin, Colombia.
PLoS One. 2020 May 21;15(5):e0221669. doi: 10.1371/journal.pone.0221669. eCollection 2020.
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive memory loss and cognitive disturbance as a consequence of the loss of cholinergic neurons in the brain, neuritic plaques and hyperphosphorylation of TAU protein. Although the underlying mechanisms leading to these events are unclear, mutations in presenilin 1 (PSEN1), e.g., E280A (PSEN1 E280A), are causative factors for autosomal dominant early-onset familial AD (FAD). Despite advances in the understanding of the physiopathology of AD, there are no efficient therapies to date. Limitations in culturing brain-derived live neurons might explain the limited effectiveness of AD research. Here, we show that mesenchymal stromal (stem) cells (MSCs) can be used to model FAD, providing novel opportunities to study cellular mechanisms and to establish therapeutic strategies. Indeed, we cultured MSCs with the FAD mutation PSEN1 E280A and wild-type (WT) PSEN1 from umbilical cords and characterized the transdifferentiation of these cells into cholinergic-like neurons (ChLNs). PSEN1 E280A ChLNs but not WT PSEN1 ChLNs exhibited increased intracellular soluble amyloid precursor protein (sAPPf) fragments and extracellular Aβ42 peptide and TAU phosphorylation (at residues Ser202/Thr205), recapitulating the molecular pathogenesis of FAD caused by mutant PSEN1. Furthermore, PSEN1 E280A ChLNs presented oxidative stress (OS) as evidenced by the oxidation of DJ-1Cys106-SH into DJ-1Cys106-SO3 and the detection of DCF-positive cells and apoptosis markers such as activated pro-apoptosis proteins p53, c-JUN, PUMA and CASPASE-3 and the concomitant loss of the mitochondrial membrane potential and DNA fragmentation. Additionally, mutant ChLNs displayed Ca2+ flux dysregulation and deficient acetylcholinesterase (AChE) activity compared to control ChLNs. Interestingly, the inhibitor JNK SP600125 almost completely blocked TAU phosphorylation. Our findings demonstrate that FAD MSC-derived cholinergic neurons with the PSEN1 E280A mutation provide important clues for the identification of targetable pathological molecules.
阿尔茨海默病（AD）是一种神经退行性疾病，其特征是由于大脑中的胆碱能神经元丧失、神经原纤维缠结和 TAU 蛋白过度磷酸化导致进行性记忆丧失和认知障碍。尽管导致这些事件的潜在机制尚不清楚，但早发性家族性 AD（FAD）的 PSEN1 基因突变，例如 E280A（PSEN1 E280A），是其致病因素。尽管对 AD 病理生理学的认识有所提高，但迄今为止尚无有效的治疗方法。培养源自大脑的活神经元的局限性可能解释了 AD 研究效果有限的原因。在这里，我们表明间充质基质（干）细胞（MSCs）可用于模拟 FAD，为研究细胞机制和建立治疗策略提供了新的机会。事实上，我们培养了携带 FAD 突变 PSEN1 E280A 和野生型（WT）PSEN1 的脐带间充质干细胞，并将这些细胞向胆碱能样神经元（ChLNs）的转分化进行了特征描述。PSEN1 E280A ChLNs 而非 WT PSEN1 ChLNs 表现出细胞内可溶性淀粉样前体蛋白（sAPPf）片段和细胞外 Aβ42 肽和 TAU 磷酸化（Ser202/Thr205 残基）增加，再现了由突变 PSEN1 引起的 FAD 的分子发病机制。此外，PSEN1 E280A ChLNs 表现出氧化应激（OS），证据是 DJ-1Cys106-SH 氧化成 DJ-1Cys106-SO3，以及 DCF 阳性细胞和凋亡标志物如激活的促凋亡蛋白 p53、c-JUN、PUMA 和 CASPASE-3 的检测，以及线粒体膜电位和 DNA 片段化的丧失。此外，与对照 ChLNs 相比，突变 ChLNs 表现出 Ca2+ 通量失调和乙酰胆碱酯酶（AChE）活性不足。有趣的是，JNK SP600125 抑制剂几乎完全阻断了 TAU 磷酸化。我们的研究结果表明，携带 PSEN1 E280A 突变的 FAD MSC 衍生的胆碱能神经元为鉴定可靶向的病理分子提供了重要线索。
