Exploring the effects of squalene in the PERK/ATF4/eIF2α/CHOP signalling pathway in an in vitro Alzheimer Disease model and in silico approach.

Recent studies emphasize the pivotal role of endoplasmic reticulum (ER) stress in Alzheimer's disease (AD), highlighting the need for further investigation into this critical link. In response to ER stress, cells increase reactive oxygen species (ROS) production, leading to heightened oxidative stress. This interplay has sparked interest in antioxidant molecules such as squalene (SQ) as potential therapeutic agents. The primary objective of this study was to examine the impact of SQ on the unfolded protein response (UPR) pathway triggered by ER stress in an in vitro AD model. Herein, molecular docking analysis was performed to evaluate SQ interactions with target proteins, followed by in vitro assays. Human bone marrow-derived mesenchymal stem cells were differentiated into neuronal-like cells and characterized via immunostaining. The cells were then exposed to Aβ1-42 toxicity to establish an in vitro AD model. To assess the effects of SQ treatment following Aβ1-42 exposure, UPR-related proteins (BIP, p-PERK, PERK, eIF2α, p-eIF2α, ATF4, CHOP) were analysed by Western blotting; ROS levels were quantified to evaluate oxidative stress, and a TUNEL assay was performed to assess apoptosis. Our findings indicate that SQ alters protein expression within the UPR pathway in the AD experimental model. Notably, amyloid-β levels were significantly reduced in the SQ-treated group (p˂0.001). Furthermore, SQ reduced ROS levels. These results suggest that SQ holds potential as a therapeutic agent for mitigating amyloid-β toxicity.