A recent study has shown that early growth response 1 (EGR1) plays a critical role in the β-amyloid cascade and tau hypotheses. In addition, evidence has suggested that EGR1 can regulate levels of amyloid-beta peptides, key molecules in the pathogenesis of Alzheimer's disease (AD). However, whether EGR1 is a deleterious or protective factor in the AD is still controversial. In this present study, we constructed an overexpression plasmid, CMV-EGFP-EGR1-Kanamycin, and transfected it into U87MG cells to investigate the effects of EGR1 expression on amyloid-β (1-40) peptide (Aβ40) levels. U87MG cells transfected by CMV-EGFP-EGR1-Kanamycin and CMV-EGFP-Kanamycin were assigned, respectively, to experimental and control groups. Fluorescence microscopy was used to observe transfection efficiencies of the plasmids after 6 hours. EGR1 messenger RNA levels were measured by quantitative reverse transcription polymerase chain reaction. Aβ40 secretion was analyzed by enzyme-linked immunosorbent assay. Expression of the amyloid precursor protein, beta-secretase enzyme, and presenilin 1 proteins were analyzed by Western blot analysis. The results showed that EGR1 overexpression increased Aβ40 secretion in vitro, possibly through increasing BACE1 expression. Based on these results, EGR1 might be a promising therapeutic target for the AD.
Keywords: Alzheimers disease (AD); amyloid precursor protein (APP); amyloid-β (1-40) peptide (Aβ40); early growth response 1 (EGR1); presenilin 1(PS1); β-secretase (BACE1).
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