BACKGROUND Inflammation is a double-edged state of immune activation that is required to resolve threats harmful to the host, but can also cause severe collateral damage. Polymorphonuclear neutrophils (PMNs), the primary leukocyte population in humans, mediate inflammation through the release of cytokines and neutrophil extracellular traps (NETs). Although the pathophysiological importance of NETs is unequivocal, the multiple molecular pathways driving NET release are not fully defined. Recently, NET release was linked to the NLRP3 inflammasome, which is regulated by Bruton's tyrosine kinase (BTK) in macrophages. OBJECTIVE As NLRP3 inflammasome regulation by BTK has not been studied in neutrophils, we explored a potential regulatory role of BTK in primary murine and human neutrophils and matched monocytes or macrophages from Btk-deficient versus wild-type mice, or from healthy donors versus BTK-deficient patients with X-linked agammaglobulinemia. METHODS Cytokine, myeloperoxidase, and matrix metalloproteinase-9 (MMP-9) release were quantified by ELISA, NET release, and inflammasome formation by immunofluorescence microscopy. RESULTS Surprisingly, in both mouse and human primary neutrophils, we observed a significant increase in NLRP3 inflammasome-dependent IL-1β and NETs when BTK was absent or inhibited, whereas IL-1β release was decreased in corresponding primary mouse macrophages or human PBMCs. This suggests a novel negative regulatory role of BTK in terms of neutrophil NLRP3 activation. IL-1β and NET release in both mouse and human primary neutrophils was strictly dependent on NLRP3, caspase-1 and, surprisingly, MMP-9. CONCLUSIONS This study highlights BTK and MMP-9 as novel and versatile inflammasome regulators and may have implications for the clinical use of BTK inhibitors.

中文翻译：

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布鲁顿酪氨酸激酶 （BTK） 和基质金属蛋白酶-9 （MMP-9） 调节原代中性粒细胞中 NLRP3 炎性小体依赖性细胞因子和中性粒细胞胞外陷阱反应。


背景 炎症是免疫激活的双刃剑状态，是解决对宿主有害的威胁所必需的，但也可能导致严重的附带损害。多形核中性粒细胞 （PMN） 是人类的主要白细胞群，通过释放细胞因子和中性粒细胞胞外陷阱 （NET） 来介导炎症。尽管 NET 的病理生理学重要性是明确的，但驱动 NET 释放的多种分子途径尚未完全定义。最近，NET 释放与 NLRP3 炎性小体有关，NLRP3 炎性小体受巨噬细胞中布鲁顿酪氨酸激酶 （BTK） 的调节。目的 由于尚未在中性粒细胞中研究 BTK 对 NLRP3 炎性小体的调节，我们探讨了 BTK 在原代小鼠和人中性粒细胞以及来自 Btk 缺陷小鼠与野生型小鼠或健康供体与 BTK 缺陷患者的匹配单核细胞或巨噬细胞中的潜在调节作用患有 X 连锁无丙种球蛋白血症。方法 ELISA 定量细胞因子、髓过氧化物酶和基质金属蛋白酶-9 （MMP-9） 的释放，NET 的释放和免疫荧光显微镜的炎性小体形成。结果令人惊讶的是，在小鼠和人原代中性粒细胞中，我们观察到当 BTK 不存在或受到抑制时，NLRP3 炎性小体依赖性 IL-1β 和 NETs 显着增加，而 IL-1β 释放在相应的原代小鼠巨噬细胞或人 PBMC 中减少。这表明 BTK 在中性粒细胞 NLRP3 激活方面具有新的负调节作用。小鼠和人原代中性粒细胞中的 IL-1β 和 NET 释放严格依赖于 NLRP3、caspase-1 和令人惊讶的 MMP-9。 结论 本研究强调 BTK 和 MMP-9 是新型和多功能的炎症调节因子，可能对 BTK 抑制剂的临床应用产生影响。