A unique serum-free murine cortical astrocyte culture to study endoplasmic reticulum stress in response to amyloid-β

Abstract

Astrocytes are integral to understand Alzheimers disease (AD) pathology but the existing serum-supplemented in vitro astrocyte culture models are not suitable to study certain stress response mechanisms. Here, we developed a serum-free murine primary cortical astrocyte culture model to study endoplasmic reticulum (ER) stress and inflammation to see the effect of amyloid-beta (A{beta}1-42). Astrocytes were cultured in a controlled serum-free environment to minimize interference from serum components. Serum-free astrocytes were exposed to oligomeric A{beta} to induce ER stress and inflammation. Initially no significant activation of eIF2, a key marker of ER stress, was observed under serum-free condition but with the removal of N-acetyl cysteine ER stress response was enhanced after 24 hours of A{beta} exposure. Subsequently, the inflammatory response, assessed through TNF- expression, was minimal in the presence of growth factors but became pronounced when these factors were withdrawn. Astrocytic reactivity, assessed by GFAP expression, was observed with prolonged A{beta} exposure, indicating a reactive astrogliosis response. Transcript analysis revealed a time-dependent shift in the expression of inflammatory modulators, with early time points showing increased anti-inflammatory markers and late exposure promoting pro-inflammatory responses. These findings highlight the potential of serum-free cultures for studying ER stress and inflammation together in astrocytes and offer insights into the complex role of these cells in AD pathophysiology.