Fig. 2.

Recombinant APEX1 downregulates TNF-α/IL-17-mediated p38 MAPK and NF-κB phosphorylation, PI3K activation, and IL-1 family production. A) Phosphorylation levels of p-p38 MAPK, p-NF-κB p65, and PI3K delta isoform (110δ) were evaluated by western blot in RA FLS stimulated with TNF-α (10 ng/ml)/IL-17 (10 ng/ml) alone or with recombinant APEX1 (10 ng/ml) for 30 min. Data represent one median experiment (left panel) with fold change of band intensity relative to unstimulated control (right panel). GAPDH served as a loading control. Each symbol represents an individual donor (n = 3), and bars represent means. Statistical analysis between TNF-α/IL-17 and TNF-α/IL-17/APEX1 was performed using the paired Student’s t-test. *p < 0.05 B) RA FLS were treated with TNF-α/IL-17 alone or with recombinant APEX1 (1, 10, and 100 ng/ml) for 1 h, and IL-1β, IL-18, IL-33, and IL-36α mRNA levels were assessed by qRT-PCR. Data represent one experiment conducted in triplicate with similar results C) RA FLS were treated with TNF-α/IL-17 alone or with recombinant APEX1 (10 ng/ml) for 1, 3, and 6 h, and IL-1β, IL-18, IL-33, and IL-36α mRNA levels were analyzed. Data represent one experiment conducted in triplicate with similar results. Data are presented as mean ± standard deviation