Single and repeated bisphenol A treatment induces ROS, Aβ and hyperphosphorylated-tau accumulation, and insulin pathways disruption, through HDAC2 and PTP1B overexpression, leading to SN56 cholinergic apoptotic cell death

Abstract

Bisphenol-A (BPA), a polymer component extensively used, produces memory and learning alterations after acute and long-term exposure. However, the mechanisms are not well known. Cortex and hippocampus neuronal networks control cognitive functions, which are innervated by basal forebrain cholinergic neurons (BFCN), and their neurodegeneration induces cognitive dysfunctions. Wild type or protein tyrosine phosphatase 1B (PTP1B), histone deacetylase 2 (HDAC2), tau or β amyloid precursor protein (βAPP) silenced SN56 cells treated with BPA (0.001 μM-100 μM) with or without N-acetylcysteine (NAC; 1 mM), following 1 and 14 days, were used, as a model of BFCN to determine the insulin pathway dysfunction, oxidative stress (OS) generation and amyloid-β (Aβ) and tau proteins accumulation involvement in the BCFN cell death induction, as a possible mechanism that could produce the cognitive disorders reported. BPA-induced BFCN cell death, after 24 h and 14 days of treatment, through insulin pathway dysfunction, OS generation, mediated by NRF2 pathway downregulation, and Aβ and tau proteins accumulation, which were in turn induced by HDAC2 and PTP1B overexpression. This is relevant information to explain the BFCN neurodegeneration mechanisms that could trigger the neurodegeneration in the rest of the regions innerved by them, leading to cognitive disorders.

Keywords: Bisphenol-A; HDAC2; Insulin; NRF2; PTP1B; SN56 cholinergic neuronal cell death.