Figure 5.

Reduced arthritis and inflammation in PAD4^−/− mice with TNFα-induced arthritis. A, Severity of clinical arthritis was scored in TNF⁺PAD4^+/+ mice (solid circles) and TNF⁺PAD4^−/− mice (open circles). Graph depicts the mean ± SEM of 12 pairs of mice. *** = P = 0.0001 versus TNF⁺PAD4^+/+ mice, by paired t-test. B, Hind legs from TNF⁺PAD4^+/+ and TNF⁺PAD4^−/− littermates at age 5 months were assessed histologically. Images are representative of 12 pairs of mice and show inflamed synovium/pannus invading cartilage and bone (arrowheads) at the tibiotalar joint. Original magnification × 100. Bar = 200 μm. C, The extent of synovitis and erosion at the tibiotalar joint was scored in a blinded manner on a scale of 0–4, and the graph depicts the mean ± SEM (n = 12 pairs of mice). * = P < 0.05 by paired t-test. D, Blood from TNF⁺PAD4^+/+ and TNF⁺PAD4^−/− mice at age 5 months was pipetted into Kit-On-A-Lid-Assay microfluidic devices. Neutrophils were captured by the P-selectin–coated surface and counted. All experiments were performed at least in triplicate. Graph depicts the mean ± SEM number of captured neutrophils from the TNF⁺PAD4^−/− mouse normalized to the number from the TNF⁺PAD4^+/+ littermate in 7 experiments. *** = P < 0.0001 by unpaired t-test. See Figure 2 for definitions.