Zhang Lu, Fang Yu, Cheng Xuan, Lian Yajun, Xu Hongliang, Zeng Zhaoshu, Zhu Hongcan
Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
Department of Intensive Care Unit, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
Cell Physiol Biochem. 2017;43(6):2446-2456. doi: 10.1159/000484449. Epub 2017 Oct 31.
TRPML1 is reported to be involved in the pathogenesis of Alzheimer's disease (AD) by regulating autophagy; however, the underlying mechanism is not completely clear.
We developed an APP/PS1 transgenic animal model that presents with AD. TRPML1 was also overexpressed in these mice. Protein expression levels were determined by Western blot. Morris water maze (MWM) and recognition tasks were performed to characterize cognitive ability. TUNEL assays were analysed for the detection of neuronal apoptosis. Primary neurons were isolated and treated with the vehicle, Aβ1-42 or Aβ1-42 + mTOR activator, as well as infected with the recombinant adenovirus TRPML1 overexpression vector in vitro. Cell viability was measured by the MTS assay, and lysosomal Ca2+ was also measured.
In the APP/PS1 transgenic mice, TRPML1 was downregulated, the PPARγ/AMPK signalling pathway was activated, the mTOR/S6K signalling pathway was suppressed, and autophagic lysosome reformation (ALR)-related proteins were upregulated. TRPML1 overexpression or treatment with PPARγ and AMPK inhibitors or an mTOR activator reduced the expression levels of ALR-related proteins, rescued the memory and recognition impairments and attenuated neuronal apoptosis in mice with the APP/PS1 transgenes. In vitro experiments showed that TRPML1 overexpression or treatment with the mTOR activator propranolol attenuated the Aβ1-42-suppressed cell viability and the Aβ1-42-decreased lysosomal [Ca2+] ion concentration in primary neurons. TRPML1 overexpression or treatment with the mTOR activator propranolol also attenuated the Aβ1-42-inhibited mTOR/S6K signalling pathway and the Aβ1-42-induced ALR-related protein expression levels.
TRPML1 is involved in the pathogenesis of AD by regulating autophagy at least in part through the PPARγ/AMPK/mTOR signallingpathway.
据报道，瞬时受体电位黏蛋白1（TRPML1）通过调节自噬参与阿尔茨海默病（AD）的发病机制；然而，其潜在机制尚不完全清楚。
我们构建了呈现AD症状的APP/PS1转基因动物模型。在这些小鼠中也过表达了TRPML1。通过蛋白质免疫印迹法测定蛋白质表达水平。进行莫里斯水迷宫（MWM）和识别任务以表征认知能力。通过TUNEL分析检测神经元凋亡。体外分离原代神经元，用溶剂、Aβ1-42或Aβ1-42 + mTOR激活剂处理，并感染重组腺病毒TRPML1过表达载体。通过MTS法测量细胞活力，同时也测量溶酶体Ca2+。
在APP/PS1转基因小鼠中，TRPML1表达下调，PPARγ/AMPK信号通路被激活，mTOR/S6K信号通路被抑制，且自噬溶酶体重组（ALR）相关蛋白上调。TRPML1过表达或用PPARγ和AMPK抑制剂或mTOR激活剂处理可降低APP/PS1转基因小鼠中ALR相关蛋白的表达水平，挽救记忆和识别障碍，并减轻神经元凋亡。体外实验表明，TRPML1过表达或用mTOR激活剂普萘洛尔处理可减轻Aβ1-42抑制的原代神经元细胞活力以及Aβ1-42降低的溶酶体[Ca2+]离子浓度。TRPML1过表达或用mTOR激活剂普萘洛尔处理还可减轻Aβ1-42抑制的mTOR/S6K信号通路以及Aβ1-42诱导的ALR相关蛋白表达水平。
TRPML1至少部分通过PPARγ/AMPK/mTOR信号通路调节自噬参与AD的发病机制。
