Inhibition of miR-128 Abates Aβ-Mediated Cytotoxicity by Targeting PPAR-γ via NF-κB Inactivation in Primary Mouse Cortical Neurons and Neuro2a Cells

Abstract

PurposeAlzheimer's disease (AD) is the sixth most common cause of death in the United States. MicroRNAs have been identified as vital players in neurodegenerative diseases, including AD. microRNA-128 (miR-128) has been shown to be dysregulated in AD. This study aimed to explore the roles and molecular mechanisms of miR-128 in AD progression.Materials and MethodsExpression patterns of miR-128 and peroxisome proliferator-activated receptor gamma (PPAR-γ) messenger RNA in clinical samples and cells were measured using RT-qPCR assay. PPAR-γ protein levels were determined by Western blot assay. Cell viability was determined by MTT assay. Cell apoptotic rate was detected by flow cytometry via double-staining of Annexin V-FITC/PI. Caspase 3 and NF-κB activity was determined by a Caspase 3 Activity Assay Kit or NF-κB p65 Transcription Factor Assay Kit, respectively. Bioinformatics prediction and luciferase reporter assay were used to investigate interactions between miR-128 and PPAR-γ 3′UTR.ResultsMiR-128 expression was upregulated and PPAR-γ expression was downregulated in plasma from AD patients and amyloid-β (Aβ)-treated primary mouse cortical neurons (MCN) and Neuro2a (N2a) cells. Inhibition of miR-128 decreased Aβ-mediated cytotoxicity through inactivation of NF-κB in MCN and N2a cells. Moreover, PPAR-γ was a target of miR-128. PPAR-γ upregulation attenuated Aβ-mediated cytotoxicity by inactivating NF-κB in MCN and N2a cells. Furthermore, PPAR-γ downregulation was able to abolish the effect of anti-miR-128 on cytotoxicity and NF-κB activity in MCN and N2a cells.ConclusionMiR-128 inhibitor decreased Aβ-mediated cytotoxicity by upregulating PPAR-γ via inactivation of NF-κB in MCN and N2a cells, providing a new potential target in AD treatment.

MicroRNA in Brain pathology: Neurodegeneration the Other Side of the Brain Cancer

“…However, other studies have shown that a decrease in the miR-128 level significantly reduced apoptosis and caspase-3 activity in AD model on primary mouse cortical neurons and Neuro2a cells. In this model, Aβ mediated toxicity was decreased by targeting PPAR-γ via inactivation of NF-κB [120]. These results were confirmed in a mouse model of AD, where a miR-128 knockout weakened AD-like performances and reduced Aβ production and inflammatory responses by targeting PPARγ [122].…”

“…Reactive oxygen species (ROS) result in hyper-upregulation of miR-128 in cultured neurons, which suggests the possibility that microRNA may mediate ROS’s pathogenic effects in AD [119]. miR-128 is highly expressed in the hippocampus of AD patients relative to age-matched controls [120,121] and its expression is upregulated in the hippocampus in an intermediate stage of AD patients [120]. However, other studies have shown that a decrease in the miR-128 level significantly reduced apoptosis and caspase-3 activity in AD model on primary mouse cortical neurons and Neuro2a cells.…”

Molecular and cellular mechanisms underlying the pathogenesis of Alzheimer’s disease

“…miRNAs may participate AD pathogenesis by modulating amyloidogenic pathways: for example, miR-346 can up-regulate APP translation and Aβ production [614]. In addition, miRNAs can activate PPAR-γ, thereby stimulating NF-κB pathways to induce cytokine release and consequent Aβ production [615]. However, how a particular neurodegenerative environment within pathological contexts can alter miRNA levels, and consequential effects in modulating the miRNA milieu requires further elucidation.…”

Plasma microRNAs biomarkers in mild cognitive impairment among patients with type 2 diabetes mellitus

“…miR-128 was reported to be overexpressed in AD patients [ 31 ]. In the present study, plasma miR-128 expression was found insignificantly higher in T2DM patients with MCI compared to T2DM patients and non diabetic individuals with normal cognitive functions.…”

“…Moreover, MÜller and co-workers [ 32 ] reported increase expression of miR-128 in the hippocampus in an intermediate stages of AD patients and to be downregulated in late stages of AD patients. In cell cultures, inhibition of miR-128 decreases Aβ-mediated cytotoxicity through inactivation of the NF-κB pathway [ 31 ].…”