Fig. 4

Effects of ER stress on gene transcription and mRNA stability in RA FLS. a FLS (n = 3) were stimulated with 1 μg/ml LPS in the presence or absence of 10 nM TG for the indicated amount of time. mRNA expression of mature and primary forms of transcripts of IL6 and IL8 was measured by qPCR. Shown is the ratio between expression observed in both experimental conditions at each time point. b FLS (n = 8) were stimulated with 1 μg/ml LPS in the presence or absence of 10 nM TG for 4 h, followed by incubation with 10 μg/ml ActD to induce transcriptional block. Cells were lysed at the indicated time points after addition of ActD, and the amount of transcript for each gene remaining in cells was analyzed by qPCR. Data are presented as a fraction of transcript detectable at each time point relative to the moment immediately after addition of ActD. Table shows 95% CIs of transcript half-life calculated using Prism software (GraphPad Software). ActD Actinomycin D; CXCL Chemokine (C-X-C motif) ligand, ER Endoplasmic reticulum, FLS Fibroblast-like synoviocytes, IL Interleukin, LPS Lipopolysaccharide, mRNA Messenger RNA, qPCR Quantitative polymerase chain reaction, RA Rheumatoid arthritis, TG Thapsigargin