Liver sinusoidal endothelial cells are the border patrol in the liver. Their open transcellular fenestrations allow the transfer of small and dissolved substances from the blood into the liver parenchymal cells. Fenestrations are dynamic structures, and many drugs and diseases alter their size and number, thus making them an important target for modulation. There is an urgent need to understand how various diseases, toxic substances, and physiological conditions influence liver endothelial cell fenestrations, and how these changes affects liver function. This work represents a straightforward quantitative proteomics study of the in vivo arsenic-stressed liver sinusoidal endothelial cells using a reverse super-SILAC based method. The aim of this study was to identify proteins, which are up- or down-regulated in response to arsenic. This knowledge will aid in identification of potential targets and mechanisms of arsenic toxicity and novel ways to reverse these changes. (C) 2019 Published by Elsevier Inc.