MicroRNA-128 knockout inhibits the development of Alzheimer's disease by targeting PPARγ in mouse models.

Affiliation

Department of Neurology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450014, China. Electronic address: [Email]

Abstract

Alzheimer's disease (AD) is a great threat for the health and life of elderly people. MicroRNA-128 (miR-128) has been reported to be abnormally expressed in the brain of AD patients and associated with the pathogenesis of AD. Our study aimed to have a deep insight into the roles and molecular basis of miR-128 in the development and progression of AD. The cognitive ability and exploratory behaviors were assessed by morris water maze and open-field tests, respectively. The concentrations of amyloid-β (Aβ) 40, Aβ 42, tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-10 and activity of β-secretase and α-secretase were determined by corresponding ELISA commercial kits. RT-qPCR assay was performed to detect miR-128 level and the mRNA expression of peroxisome proliferator-activated receptor gamma (PPARγ), ionized calcium-binding adaptor molecule 1 (Iba1) and glial fibrillary acidic protein (GFAP). Western blot assay was conducted to determine protein expression of PPARγ, amyloid precursor protein (APP), β-APP cleaving enzyme (BACE1), sAPPα and sAPPβ. The effect of miR-128 and PPARγ on amyloid plaque formation was assessed by immunohistochemistry assay. PPARγ mean optical density was determined by immunofluorescence assay. The interaction between miR-128 and PPARγ were validated by bioinformatics analysis and luciferase reporter assay. We found AD mice showed AD-like performance and an increased cerebral cortex Aβ production. MiR-128 expression was upregulated and PPARγ expression was downregulated in cerebral cortex of AD mice. Moreover, PPARγ was a target of miR-128. Additionally, miR-128 knockout or PPARγ upregulation inhibited AD-like performances, amyloid plaque formation, Aβ generation, APP amyloidogenic processing and inflammatory responses in AD mice, while these effects of miR-128 knockout were abrogated by PPARγ inhibitor. The results indicated MiR-128 knockout weakened AD-like performances, and reduced Aβ production and inflammatory responses by targeting PPARγ in AD mice.

Keywords

3×Tg-AD triple transgenic mouse model,Alzheimer's disease,PPARγ,miR-128,