Immunohistochemical detection of the unfolded protein response in atherosclerotic plaques

It is well established that activation of the unfolded protein response (UPR) occurs during all stages of plaque development and progression. Mouse models of atherosclerosis have allowed the study of the UPR in the complex environment of lesions which are composed of different cell types, abundant extracellular matrix, as well as necrotic and apoptotic areas. For proper evaluation of the UPR, the processing, sectioning, and staining of lesions have to be performed in a consistent and reproducible manner. In this chapter, we describe in detail how to embed aortic roots in paraffin, cut serial sections through the aortic root, measure lesion size, and stain paraffin sections by immunohistochemistry, immunofluorescence, and the terminal dUTP nick-end-labeling (TUNEL) technique, with special attention to the proteins involved in the UPR.