Gout is a prevalent and incapacitating disease triggered by the deposition of monosodium urate (MSU) crystals in joints, which are also massively infiltrated by neutrophils. The interaction of the latter with MSU crystals triggers several responses, including the generation of inflammatory mediators and of neutrophil extracellular traps (NETs). Though some of the signaling events mobilized by MSU in neutrophils have been described (e.g., Src family kinases, Syk, PKC, PI3K), the picture remains fragmentary. Likewise, the impact of these signaling events on cellular responses is incompletely understood. In this study, we examined transcriptomic changes triggered by MSU in neutrophils and their impact on the corresponding proteins, as well as the role of various signaling pathways in prominent functional responses. We report for the first time that neutrophils can secrete the monocyte chemoattractant, CCL4, in response to MSU. Accordingly, we found that transcription factors NF-κB, CREB, and C/EBP are belatedly activated by MSU crystals, and at least the former is involved in chemokine generation. Moreover, we show that MAPKs and Akt are activated by MSU in neutrophils, that they are under the control of TAK1 and Syk, and that they participate in cytokine generation and NETosis. In the latter instance, we found the phenomenon to be independent of endogenous ROS, but under the control of PAD4. We finally provide evidence that endogenous factors contribute to the belated phosphorylation of kinases and transcription factors in response to MSU. Collectively, our findings unveil potentially important therapeutic targets for gouty arthritis.

痛风是一种普遍存在的致残性疾病，由关节中的尿酸单钠（MSU）晶体沉积引起，而中性粒细胞也大量渗透了该疾病。后者与MSU晶体的相互作用触发了多种反应，包括炎性介质和嗜中性粒细胞外陷阱（NETs）的产生。尽管已描述了MSU在嗜中性粒细胞中动员的某些信号事件（例如Src家族激酶，Syk，PKC，PI3K），但该图仍然是零碎的。同样，这些信号事件对细胞应答的影响还不完全清楚。在这项研究中，我们检查了中性粒细胞中MSU触发的转录组变化及其对相应蛋白质的影响，以及各种信号通路在重要功能反应中的作用。我们首次报道中性粒细胞可以分泌单核细胞趋化因子CCL4，以响应MSU。因此，我们发现转录因子NF-κB，CREB和C / EBP被MSU晶体延迟激活，至少前者参与趋化因子的产生。此外，我们显示MSU在中性粒细胞中激活MAPK和Akt，它们在TAK1和Syk的控制下，并且它们参与细胞因子的产生和NETosis。在后一种情况下，我们发现该现象与内源性ROS无关，但受PAD4的控制。我们最终提供证据，证明内源性因素促成迟来的MSU激酶和转录因子磷酸化。总的来说，我们的发现揭示了痛风性关节炎的潜在重要治疗靶点。