Retracted: Palmitate‐induced C/EBP homologous protein activation leads to NF‐κB‐mediated increase in BACE1 activity and amyloid beta genesis

Abstract The etiology of Alzheimer's disease ( AD ) is egregiously comprehended, but epidemiological studies have posited that diets rich in the saturated fatty acid palmitic acid (palmitate) are a significant risk factor. The production and accumulation of amyloid beta peptide (Aβ) is considered the core pathological molecular event in the pathogenesis of AD . The rate‐limiting step in Aβ genesis from amyloid‐β precursor protein (Aβ PP ) is catalyzed by the enzyme β‐site amyloid precursor protein cleaving enzyme 1 ( BACE 1), the expression and enzymatic activity of which is significantly up‐regulated in the AD brain. In this study, we determined the molecular mechanisms that potentially underlie the palmitate‐induced up‐regulation in BACE 1 expression and augmented Aβ production. We demonstrate that a palmitate‐enriched diet and exogenous palmitate treatment evoke an increase in BACE 1 expression and activity leading to enhanced Aβ genesis in the mouse brain and SH ‐ SY 5Y‐ APP S we cells, respectively, through the activation of the transcription factor NF ‐κB. Chromatin immunoprecipitation (Ch IP ) assays and luciferase reporter assays revealed that palmitate enhances BACE 1 expression by increasing the binding of NF ‐κB in the BACE 1 promoter followed by an enhancement in the transactivation of the BACE 1 promoter. Elucidation and delineation of upstream molecular events unveiled a critical role of the endoplasmic reticulum stress‐associated transcription factor, C/ EBP homologous protein ( CHOP ) in the palmitate‐induced NF ‐κB activation, as CHOP knock‐down cells and Chop −/− mice do not exhibit the same degree of NF ‐κB activation in response to the palmitate challenge. Our study delineates a novel CHOP ‐ NF ‐κB signaling pathway that mediates palmitate‐induced up‐regulation of BACE 1 expression and Aβ genesis. image