Department of Life Science, Chung-Ang University, Seoul, Republic of Korea.
Department of Anatomy and Cell Biology, College of Medicine, Chung-Ang University, Seoul, Republic of Korea.
J Cell Physiol. 2023 Dec;238(12):2812-2826. doi: 10.1002/jcp.31131. Epub 2023 Oct 6.
Excessive production and accumulation of amyloid-beta (Aβ) in the brain are one of the hallmarks of Alzheimer's disease (AD). Although oxidative stress is known to trigger and promote the progression of AD, the molecular relationship between oxidative stress and Aβ production is not yet fully understood. In this study, we demonstrate that microtubule acetylation induced by oxidative stress plays a critical role in Aβ production and secretion by altering the subcellular distribution of Aβ precursor protein (APP)-containing lysosomal vesicles. Under oxidative stress, both H4-APP and HEK293T-APP cell lines showed increased microtubule acetylation and Aβ secretion. Knockdown (KD) of alpha-tubulin N-acetyltransferase 1 (ATAT1) by using a lentiviral shRNA not only inhibited the generation of intermediate APP fragments, such as β-CTF and AICD, but also suppressed Aβ secretion. Oxidative stress promoted the dispersion of LAMP1-positive vesicles to the periphery of the cell through microtubule acetylation, leading to the formation of neutralized lysosomal vesicles (NLVs), which was inhibited by ATAT1 KD. Treatment of the cells with the dynein ATPase inhibitor EHNA or downregulation of LIS1, a regulator of dynein-mediated intracellular transport, increased the peripheral localization of NLVs and promoted Aβ secretion, whereas KD of ADP ribosylation factor like GTPase 8B showed the opposite result. ATAT1 KD in the hippocampal region of the 5×FAD AD mouse model also showed significant reductions in Aβ plaque accumulation and memory loss. Taken together, these findings suggest that oxidative stress-induced microtubule acetylation promotes the peripheral localization of lysosomal vesicles to form NLVs, thereby enhancing Aβ secretion.
脑内淀粉样β（Aβ）的过度产生和积累是阿尔茨海默病（AD）的标志之一。尽管氧化应激已知可引发和促进 AD 的进展，但氧化应激与 Aβ产生之间的分子关系尚未完全了解。在这项研究中，我们证明了氧化应激诱导的微管乙酰化通过改变含有 Aβ前体蛋白（APP）的溶酶体囊泡的亚细胞分布，在 Aβ产生和分泌中起关键作用。在氧化应激下，H4-APP 和 HEK293T-APP 细胞系均显示出微管乙酰化增加和 Aβ分泌增加。使用慢病毒 shRNA 敲低（KD）α-微管蛋白 N-乙酰转移酶 1（ATAT1）不仅抑制了中间 APP 片段（如β-CTF 和 AICD）的产生，还抑制了 Aβ的分泌。氧化应激通过微管乙酰化促进 LAMP1 阳性囊泡分散到细胞周围，导致形成中和的溶酶体囊泡（NLVs），这一过程被 ATAT1 KD 抑制。用胞质动力蛋白 ATP 酶抑制剂 EHNA 处理细胞或下调胞质动力蛋白介导的细胞内运输调节剂 LIS1，增加了 NLVs 的外周定位并促进了 Aβ的分泌，而 ADP 核糖基化因子样 GTPase 8B 的 KD 则显示出相反的结果。在 5×FAD AD 小鼠模型的海马区进行 ATAT1 KD 也显示出 Aβ斑块积累减少和记忆丧失显著减轻。总之，这些发现表明，氧化应激诱导的微管乙酰化促进溶酶体囊泡的外周定位形成 NLVs，从而增强 Aβ的分泌。
