Fig. 5

ERAP1 is a regulator of ER stress. Bone marrow-derived macrophages (2 × 10⁶ cells) were plated into 6-well plates. Cells were pretreated with 500 ug/mL of TUDCA for 48 h and were then stimulated with LPS (25 ng/mL) for 18 h (A). Cells were harvested for RNA isolation. mRNA levels of ATF6, ATF4, BiP, CHOP, sXBP1 and GAPDH were evaluated. BMDMs were primed with LPS overnight, incubated with TUDCA the next day, and then stimulated with nigericin for an additional 16 h. Supernatant was collected and 23-bead Bioplex was run for cytokine examination of IL-1β and IL-1α (C). CD4⁺ T cells were isolated from total splenocytes, pooled, and plated at 3 × 10⁶ cells per well into 6-well plates. Cells were stimulated with LPS (20 ng/mL) for approximately 12 h. Cells were harvested for RNA isolation. Cells were collected from 5 WT and 4 ERAP1^−/− cells and kept separate during the experiment. mRNA levels of ER stress genes BiP and sXBP1 (B) was assessed. Raw Ct values from representative experiments are presented in Supplemental Information (Additional file 5: Supplemental Tables). Data are expressed as means ± SEM. These figures are representative of four independent experiments