Zhou Xiuya, Du Kaili, Mao Tian, Wang Ning, Zhang Lifei, Tian Yuan, Liu Ting, Wang Li, Wang Xiaohui
Basic Medical Sciences Center, Shanxi Medical University, Taiyuan, China.
Department of Pathology, West China Hospital, West China Medical School, Sichuan University, Chengdu, China.
iScience. 2024 Nov 18;27(12):111413. doi: 10.1016/j.isci.2024.111413. eCollection 2024 Dec 20.
We aim to investigate muscle ARNT-like protein 1 (BMAL1) regulation of syntaxin17 (STX17) in mouse hippocampal neurons, focusing on autophagy and amyloid-β (Aβ) deposition. Autophagosome-lysosome fusion in APP/PS1 hippocampal tissues was observed using transmission electron microscopy, while mRNA levels of LC3II and P62 were measured via reverse-transcription PCR (RT-PCR) after Amyloid precursor protein (APP) overexpression. STX17, linked to autophagy and differentially expressed in Alzheimer's disease (AD) brains, was knocked down or overexpressed to assess its effects. The results showed that reduced STX17 impairs autophagosome-lysosome fusion, leading to abnormal Aβ deposition. Coimmunoprecipitation (Co-IP) and immunofluorescence confirmed STX17 interaction with SNAP29 and VAMP8 to form SNARE complexes. Furthermore, BMAL1 binding to STX17 was examined using luciferase assays. Circadian rhythm disturbances and decreased BMAL1 expression in APP/PS1 mice were noted, while BMAL1 overexpression upregulated STX17 expression and promoted autophagy to reduce Aβ deposition. Thus, the BMAL1 protein can promote STX17 transcription to induce STX17-SNAP29-VAMP8 complex formation to clear intracellular Aβ through autophagy.
我们旨在研究小鼠海马神经元中肌肉芳香烃受体核转运蛋白样蛋白1（BMAL1）对 syntaxin17（STX17）的调控作用，重点关注自噬和淀粉样β蛋白（Aβ）沉积。使用透射电子显微镜观察APP/PS1海马组织中的自噬体-溶酶体融合情况，同时在淀粉样前体蛋白（APP）过表达后，通过逆转录聚合酶链反应（RT-PCR）测量LC3II和P62的mRNA水平。敲低或过表达与自噬相关且在阿尔茨海默病（AD）大脑中差异表达的STX17，以评估其作用。结果表明，STX17减少会损害自噬体-溶酶体融合，导致Aβ异常沉积。免疫共沉淀（Co-IP）和免疫荧光证实STX17与SNAP29和VAMP8相互作用形成SNARE复合体。此外，使用荧光素酶报告基因检测法检测BMAL1与STX17的结合情况。注意到APP/PS1小鼠存在昼夜节律紊乱和BMAL1表达降低的情况，而BMAL1过表达会上调STX17表达并促进自噬以减少Aβ沉积。因此，BMAL1蛋白可促进STX17转录，诱导STX17-SNAP29-VAMP8复合体形成，通过自噬清除细胞内Aβ。
