Inhibition of miR-128 Abates A beta-Mediated Cytotoxicity by Targeting PPAR-gamma via NF-kappa B Inactivation in Primary Mouse Cortical Neurons and Neuro2a Cells

Purpose: Alzheimer'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 Methods: Expression patterns of miR-128 and peroxisome proliferator-activated receptor gamma (PPAR-gamma) messenger RNA in clinical samples and cells were measured using RT-qPCR assay. PPAR-gamma 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-kappa B activity was determined by a Caspase 3 Activity Assay Kit or NF-kappa B p65 Transcription Factor Assay Kit, respectively. Bioinformatics prediction and luciferase reporter assay were used to investigate interactions between miR-128 and PPAR-gamma 3'UTR. Results: MiR-128 expression was upregulated and PPAR-gamma expression was downregulated in plasma from AD patients and amyloid-beta (A beta)-treated primary mouse cortical neurons (MCN) and Neuro2a (N2a) cells. Inhibition of miR-128 decreased A beta-mediated cytotoxicity through inactivation of NF-kappa B in MCN and N2a cells. Moreover, PPAR-gamma was a target of miR-128. PPAR-gamma upregulation attenuated A beta-mediated cytotoxicity by inactivating NF-kappa B in MCN and N2a cells. Furthermore, PPAR-gamma downregulation was able to abolish the effect of anti-miR-128 on cytotoxicity and NF-kappa B activity in MCN and N2a cells. Conclusion: MiR-128 inhibitor decreased A beta-mediated cytotoxicity by upregulating PPAR-gamma via inactivation of NF-kappa B in MCN and N2a cells, providing a new potential target in AD treatment.