Fig. (3) Erstressin (Compound 1) induces biochemical markers of ER stress and expression of genes involved in the UPR. Panel A. Erstressin increases mRNA levels of ER stress genes. Heat map of normalized microarray data from A172 cells simultaneously induced with pro-inflammatory cytokines and treated with indicated compound at 10 µM for 6 hours. A selection of UPR-related genes is shown. Data are shown as a ratio of expression with compound treatment versus vehicle. Red indicates up-regulation, green down-regulation, and black shows no difference between compound and the vehicle control. Panel B. Immunoblot of extracts from RAW 264.7 cells after 30 minutes treatment with compound shows elevated phosphorylation of serine 51 of eIF-2α when treated with erstressin (Es, 10 µM) or thapsigargin (Tg, 1 µM), but not with nostressin (Ns, 10 µM) or vehicle (Veh) alone. Panel C.XBP-1 rtPCR of RNA isolated form HeLa cells following treatment for 1 hour with compound shows the spliced variant (XBP-1s) present in cells treated with thapsigargin (Tg, 50 nM) and erstressin (Es, 20 µM), but not in cells treated with nostressin (Ns, 20 µM).