Itsuno Maika, Tanabe Hirokazu, Sano Etsuko, Sasaki Takashi, Oyama Chisato, Bannai Hiroko, Saito Koichi, Nakata Kazuhiko, Endoh-Yamagami Setsu, Okano Hideyuki, Maeda Sumihiro
Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan.
FUJIFILM Corporation, Bio Science & Engineering Laboratories, 577 Ushijima, Kaisei-cho, Ashigarakami-gun, Kanagawa 258-8577, Japan.
Regen Ther. 2024 Dec 24;28:201-213. doi: 10.1016/j.reth.2024.12.009. eCollection 2025 Mar.
Tau protein plays a pivotal role in the pathogenesis of Alzheimer's disease (AD) and in regulating neuronal excitability. Among tau-coding microtubule associated protein tau () gene mutations, the A152T mutation is reported to increase the risk of AD and neuronal excitability in mouse models.
To investigate the effects of gene expression and its mutations on neuronal activity in human neurons, we employed genome editing technology to introduce the A152T or P301S mutations into induced pluripotent stem cells (iPSCs). We then differentiated them into excitatory and inhibitory neurons. As a control, iPSCs in which the gene was replaced with a fluorescent protein were also created.
In excitatory neuronal cultures, the A152T mutation was found to enhance spontaneous neuronal activity and the association of tau and Fyn. However, in inhibitory neuron-enriched cultures, the A152T mutation did not affect neuronal activity. Inhibition of NMDA receptors (NMDAR) and the reduction of tau protein levels decreased neuronal excitability in both A152T/A152T and healthy control (WT/WT) excitatory neurons. In addition, the A152T mutation increased the interaction between tau and Fyn. These findings suggest that the tau-Fyn interaction plays a critical role in regulating neuronal activity under physiological conditions, while the A152T mutation enhances neuronal activity by strengthening this endogenous interaction between tau and Fyn. In addition, transcriptomic analysis revealed structural changes specific to excitatory neurons with the A152T mutation. Common changes observed in both A152T and P301S lines recapitulated a dedifferentiation phenotype, consistent with previous reports.
These data demonstrate that the A152T mutation in the gene increases neuronal excitability through the tau-Fyn-NMDAR pathway in excitatory neurons, shedding light on its role in AD pathogenesis.
Tau蛋白在阿尔茨海默病（AD）的发病机制以及调节神经元兴奋性中起关键作用。在tau编码微管相关蛋白tau（）基因突变中，据报道A152T突变会增加小鼠模型中患AD和神经元兴奋性的风险。
为了研究基因表达及其突变对人类神经元中神经元活动的影响，我们采用基因组编辑技术将A152T或P301S突变引入诱导多能干细胞（iPSC）。然后我们将它们分化为兴奋性和抑制性神经元。作为对照，还创建了用荧光蛋白替换基因的iPSC。
在兴奋性神经元培养物中，发现A152T突变增强了神经元的自发活动以及tau与Fyn的关联。然而，在富含抑制性神经元的培养物中，A152T突变并未影响神经元活动。抑制NMDA受体（NMDAR）和降低tau蛋白水平降低了A152T/A152T和健康对照（WT/WT）兴奋性神经元的神经元兴奋性。此外，A152T突变增加了tau与Fyn之间的相互作用。这些发现表明，tau-Fyn相互作用在生理条件下调节神经元活动中起关键作用，而A152T突变通过加强tau与Fyn之间的这种内源性相互作用来增强神经元活动。此外，转录组分析揭示了具有A152T突变的兴奋性神经元特有的结构变化。在A152T和P301S系中观察到的共同变化概括了一种去分化表型，与先前的报道一致。
这些数据表明，基因中的A152T突变通过兴奋性神经元中的tau-Fyn-NMDAR途径增加神经元兴奋性，揭示了其在AD发病机制中的作用。
