Fig. 6. Downregulation of IFNAR1 in MDSCs is mediated by p38.
a IFNAR1 levels on PMN-MDSCs from tumor-free or WT and p38 KO (Mapk14Δ/Δ) TB mice (n = 3 for tumor-free and WT groups, n = 6 for p38 KO group). Data are expressed as mean ± SEM and the p values were calculated using unpaired two-sided Student’s t test. b Phosphorylation and total p38 protein in BM PMNs treated with 20% TES for 18 h in vitro. A typical example of two performed experiments is shown. c Histogram (left) of phosphorylation of p38 (p-p38) in spleen (red) and tumor (blue) PMN-MDSCs compared to isotype (gray) (n = 4; right). p Value was calculated in unpaired two-sided Student’s t test. d BM PMNs were cultured in 0.5% O2 for 2 h and p-p38 was measured by flow cytometry (n = 2). e IFNAR1 levels on BM PMNs from WT or p38 KO cultured with 30% TES in normoxia or hypoxia for 16–18 h (n = 3). Data are expressed as mean ± SEM and the p values were calculated using unpaired two-sided Student’s t test. f Monocytes and PMN were isolated from bone marrows from naïve mice, treated for 18 h in vitro with 20% of TES. Cells were then lysed and phospho-p38 and total p38 measured by western blot. Experiments were performed twice with the same result. g Totally, 1 × 107 of THP-1 cells were pretreated with vehicle (DMSO) or p38 inhibitor LY2228820 1 h prior to the 1 h treatment with 1 μM THG or 30 min treatment with MC38 tumor conditioned media (75%, v/v). Serum-free medium (SFM) served as control. Cell lysates were immunoprecipitated with IFNAR1 antibody and probed with anti-ubiquitin antibody. Whole-cell lysates (WCL) were used to evaluate IFNAR1 and p-IFNAR1 proteins. Two experiments with the same results were performed. h Phosphorylated and total p38 protein in HD PMNs treated with different TES (30%) or THG (1 µM) for 16–18 h in vitro.