Fig. 1

Engulfment of MSU crystal-induced NETs by synovial fluid macrophages. a Fluorescence units were measured after incubation of SFMCs with or without SYTOX Green-labeled NETs. The NET engulfment ratio was determined as the ratio of fluorescence units of SFMCs with NETs to that of SFMCs alone. When indicated, the engulfment ratio was calculated after exposure to MSU crystals during incubation. b Flow cytometric analysis of intracellular SYTOX Green in CD14⁺ macrophages (CD14⁺CD1c⁻CD3⁻CD19⁻CD56⁻ viable cells) from the SFMCs of gout patients. Statistical analysis (left) and representative plots (right) are shown. c NET uptake by synovial macrophages visualized based on the intracellular expression of neutrophil elastase (NE) (yellow) and myeloperoxidase (MPO) (green). Synovial macrophages were identified by staining for Hoechst 33342 (blue) and CD14 (red). Scale bar represents 5 μm. A quantitative comparison of NET formation measured by NE or MPO between the indicated conditions (right). gMFI, geometric mean fluorescence intensity. **P value < 0.01, ***P value < 0.001, ****P value < 0.0001