Endoplasmic reticulum stress stimulates the release of extracellular vesicles carrying danger-associated molecular pattern (DAMP) molecules

Disturbances in endoplasmic reticulum (ER) function lead to ER stress which, when severe or prolonged, may result in apoptosis. Severe ER stress has been implicated in several pathological conditions including pre-eclampsia, a multisystem disorder of pregnancy associated with the release of pro-inflammatory factors from the placenta into the maternal circulation. Here, we show that severe ER stress induced by two distinct mechanisms in BeWo choriocarcinoma cells leads to the release of extracellular vesicles (EVs) carrying pro-inflammatory damage-associated molecular pattern (DAMP) molecules. Co-treatment with the antioxidant pyrrolidine dithiocarbamate results in a reduction in ER stress-induced EV-associated DAMP release. We further demonstrate that severe ER stress is associated with changes in the expression of several stress-related proteins, notably Cited-2 and phosphorylated JNK. Together, these data indicate that severe ER stress-mediated release of EV-associated DAMPs may contribute to the heightened systemic maternal inflammatory response characteristic of pre-eclampsia and may also be relevant to other chronic inflammatory diseases which display elevated ER stress.