Tunicamycin induced endoplasmatic reticulum changes in endothelial cells investigated in vitro by confocal Raman imaging

The paper describes how tunicamycin (Tu), the most widely used pharmacological agents for inducing endoplasmic reticulum (ER)-stress, interacts with endothelial cells. Our results show that tunicamycin enters the cells and accumulates within the ER area. The ER stress takes place when improperly folded or damaged proteins begin to accumulate, however the spectroscopic markers of these changes have not been identified as yet. In this work, Raman spectroscopy and Scanning Electron Microscopy imaging of individual endothelial cells treated with Tu were performed. The changes in biochemical composition of endothelial cells induced by Tu attributed to the ER-stress were studied in detail. A main feature of the Tu impact on cells was a decrease of phospholipids content in the area of ER, and the most abundant lipid with the phosphorus groups found there was identified as sphingomyelin.