Figure 3.

Effects of AZE treatment on the expression of ER stress/UPR genes. Gene expression was measured using real-time qPCR and quantified using the ΔCt method after normalization to the S18 housekeeping gene. Bar graphs show the differential expressions of the following upstream and downstream regulators of the ER stress/UPR response: ATF6, PERK (also known as EIF2AK3), IRE1α (also known as ERN1), ATF4, GADD34 (also known as PPP1R15A), XBP1 and DDIT3 (also known as CHOP). A schematic diagram showing the main ER stress/UPR pathways and biological outcomes (apoptosis/autophagy or survival) are shown on the right. Relative expression levels of (A) ATF6, (B) PERK, (C) IRE1α, (D) ATF4, (E) GADD34, (F) XBP1 and (G) DDIT3 transcripts were measured in untreated (control) and AZE-treated BV2 microglial cells at various times (1, 6 and 24 h, respectively). Results are presented as mean fold changes in controls ± SEM of three independent experiments, each run using two biological replicates per experiment (n = 6). * p < 0.05, ** p < 0.01 or *** p < 0.001 vs. control, as determined by repeated measures ANOVAs followed by Tukey post hoc tests. Aze = L-azetidine-2-carboxylic acid; ATF6 = activating transcription factor 6; PERK = protein kinase R-like endoplasmic reticulum kinase (also known as EIF2AK3 = eukaryotic translation initiation factor 2-alpha kinase 3); IRE1α = inositol-requiring transmembrane kinase/endoribonuclease 1α (also known as ERN1 = endoplasmic reticulum to nucleus signaling 1); ATF4 = activating transcription factor 4; GADD34 = growth arrest and DNA damage-inducible protein (also known as PPP1R15A = protein phosphatase 1 regulatory subunit 15A); XBP1 = X-box binding protein 1; DDIT3 = DNA damage inducible transcript 3 (also known as CHOP = C/EBP homologous protein); RIDD = regulated IRE1α-dependent decay; JNK = c-Jun N-terminal kinase.