Cadmium toxicity on endoplasmic reticulum functioning.

Cadmium (Cd) is a heavy metal pollutant widely distributed in the environment due to industrial activities, mining, and agricultural practices. Cadmium-induced Toxicity exerts profound effects on ER functioning through multiple mechanisms, leading to cellular dysfunction and pathological consequences. Cadmium disrupts protein folding and activates the unfolded protein response (UPR). Cd exposure leads to the accumulation of misfolded proteins, triggering UPR pathways mediated by critical ER transmembrane sensors: IRE1, PERK, and ATF6. The subsequent UPR aims to restore ER homeostasis but can also induce apoptosis under severe stress conditions. Cd disrupts ER calcium homeostasis by inhibiting the SERCA pump, further exacerbating ER stress. The generation of reactive oxygen species (ROS also plays a critical role in Cd toxicity, damaging ER-resident proteins and amplifying UPR activation). Cadmium also affects the lipid metabolism. This review examines the mechanisms by which Cd toxicity impairs ER functioning, disruption of protein folding and quality control mechanisms, and dysregulation of calcium signaling and lipid metabolism. The subsequent cellular consequences, including oxidative stress, apoptosis, and inflammation, are discussed in the context of Cd-induced pathogenesis of diseases such as Cancer and neurodegenerative and cardiovascular disorders. Finally, potential therapeutic strategies must be explored to mitigate the adverse effects of Cd on ER functioning and human health.