Abstract

Objective

To explore the role of protease nexin-1 (PN-1) in Alzheimer’s disease (AD) via the sonic hedgehog (SHH) pathway.

Methods

PN-1 lentiviral activation particles were injected into APP/PS1 transgenic AD and wild-type (WT) mice; these mice were subjected to the Morris water maze test, followed by ELISA, thioflavin S staining and NeuN-TUNEL dual staining. HT22 cells were induced with Aβ_1–42 and treated with PN-1 siRNA and/or cyclopamine (an SHH signaling inhibitor). The cells were then subjected to MTT and Annexin V-FITC/PI analyses. qRT-PCR and Western blotting were conducted to measure mRNA and protein expression.

Results

The escape latency of the APP/PS1 transgenic AD mice was extended with a decreased number of platform crossings; in addition, increased Aβ deposits, Aβ_1–42 levels and hippocampal neuron apoptosis were observed in the brain tissues of AD mice. However, these changes were improved by PN-1 lentiviral activation particles. In addition, PN-1 overexpression inhibited the SHH pathway in AD mice. Moreover, PN-1 overexpression abolished the Aβ_1–42-induced activation of the SHH pathway in HT22 cells. In addition, Aβ_1–42 induction resulted in an increased apoptotic rate and decreased cell viability of HT22 cells; however, these effects were reversed by PN-1 or cyclopamine. Compared with that in the PN-1 siRNA + cyclopamine + Aβ_1–42 group, apoptosis of HT22 cells in the cyclopamine + Aβ_1–42 group was reduced and cell viability was improved.

Conclusion

PN-1, by blocking SHH pathway, reduced apoptosis of hippocampal neurons to improve spatial learning and memory ability, thereby playing a protective role in AD.

中文翻译：

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蛋白酶 nexin-1 通过调节声波刺猬信号通路来预防阿尔茨海默病

摘要

客观的

探讨蛋白酶 nexin-1 (PN-1)通过声波刺猬 (SHH) 通路在阿尔茨海默病 (AD)中的作用。

方法

将PN-1慢病毒激活颗粒注射到APP/PS1转基因AD和野生型（WT）小鼠体内；对这些小鼠进行Morris水迷宫试验，随后进行ELISA、硫代黄素S染色和NeuN-TUNEL双重染色。HT22 细胞用 Aβ _1-42诱导并用 PN-1 siRNA 和/或环巴胺（一种 SHH 信号传导抑制剂）处理。然后对细胞进行 MTT 和膜联蛋白 V-FITC/PI 分析。进行qRT-PCR和Western印迹以测量mRNA和蛋白质表达。

结果

APP/PS1转基因AD小鼠的逃逸潜伏期随着平台穿越次数的减少而延长；此外，在 AD 小鼠的脑组织中观察到Aβ 沉积增加、Aβ _{1-42水平和海马神经元凋亡。}然而，PN-1 慢病毒激活颗粒改善了这些变化。此外，PN-1 过表达抑制 AD 小鼠的 SHH 通路。此外，PN-1 过表达消除了 Aβ _1-42诱导的 HT22 细胞中 SHH 通路的激活。此外，Aβ _1-42诱导导致 HT22 细胞的凋亡率增加和细胞活力降低；然而，这些影响被 PN-1 或环巴胺逆转。与 PN-1 siRNA + 环巴胺 + Aβ _{1-42相比环巴胺+ Aβ1-42}组HT22细胞凋亡减少，细胞活力提高。

结论

PN-1通过阻断SHH通路，减少海马神经元凋亡，提高空间学习记忆能力，从而对AD起到保护作用。