Figure 5.

15-PGDH inhibition attenuates the conversion of SPMs to biologically inactive metabolites and regulates markers of inflammation in diseased tendon stromal cells. (A,B) Diseased tendon stromal cells isolated from patients with supraspinatus tendinopathy were pre-incubated with 10μM indomethacin (Indo) or 25 μM 15-PGDH inhibitor (SW033291) for 2 h, followed by incubation in 10 nM of 15-epi-LXA₄ or MaR1 or vehicle for 24 h at 37 °C. Incubations were then treated with IL-1β for 24 h at 37 °C. Lipid mediators were identified and quantified using lipid mediator profiling. (A) 15-oxo-LXA₄ and 14-oxo-MaR1 concentrations; (B) 15-epi-LXA₄ and MaR1 concentrations relative to amounts added to each incubation. Statistically significant differences were calculated using one-way ANOVA followed by Tukey post hoc test. Data are shown as means and SEM, n = 3 separate donors. *p < 0.05 vs cells + IL-1β. (C) ELISA assay of IL-6 protein secretion from IL-1β stimulated diseased tendon cells in the presence of 15-PGDH inhibitors and 15-epi-LXA₄ or MaR1. Data are shown as means and SEM, n = 4 separate donors. **P < 0.01. (D) Representative immunofluorescence images showing staining for PDPN (green), STAT-1 (green), IL-6 (red) and nuclei (cyan) in IL-1β-stimulated diseased tendon stromal cells incubated in 10 μM indomethacin and 10 nM 15-epi-LXA₄ or vehicle control media (n = 3 separate donors). Scale bar, 20 μm.