From the Department of Surgery (A.K.M., M.S., J.P.D., N.P., V.E.L., G.S., G.A., G.R.U.), Department of Pharmacology (A.K.M., V.S., N.L.), Robert M. Berne Cardiovascular Research Center (A.K.M., N.L., G.A., G.R.U.), Department of Molecular Physiology and Biological Physics (G.R.U.), and Department of Biomedical Engineering (G.A.), University of Virginia, Charlottesville.
Arterioscler Thromb Vasc Biol. 2018 Apr;38(4):843-853. doi: 10.1161/ATVBAHA.117.309897. Epub 2018 Feb 22.
Neutrophils promote experimental abdominal aortic aneurysm (AAA) formation via a mechanism that is independent from MMPs (matrix metalloproteinases). Recently, we reported a dominant role of IL (interleukin)-1β in the formation of murine experimental AAAs. Here, the hypothesis that IL-1β-induced neutrophil extracellular trap formation (NETosis) promotes AAA was tested.
NETs were identified through colocalized staining of neutrophil, Cit-H3 (citrullinated histone H3), and DNA, using immunohistochemistry. NETs were detected in human AAAs and were colocalized with IL-1β. In vitro, IL-1RA attenuated IL-1β-induced NETosis in human neutrophils. Mechanistically, IL-1β treatment of isolated neutrophils induced nuclear localization of ceramide synthase 6 and synthesis of C16-ceramide, which was inhibited by IL-1RA or fumonisin B1, an inhibitor of ceramide synthesis. Furthermore, IL-1RA or fumonisin B1 attenuated IL1-β-induced NETosis. In an experimental model of murine AAA, NETs were detected at a very early stage-day 3 of aneurysm induction. IL-1β-knockout mice demonstrated significantly lower infiltration of neutrophils to aorta and were protected from AAA. Adoptive transfer of wild-type neutrophils promoted AAA formation in IL-1β-knockout mice. Moreover, treatment of wild-type mice with Cl-amidine, an inhibitor NETosis, significantly attenuated AAA formation, whereas, treatment with deoxyribonuclease, a DNA digesting enzyme, had no effect on AAA formation.
Altogether, the results suggest a dominant role of IL-1β-induced NETosis in AAA formation.
中性粒细胞通过一种独立于基质金属蛋白酶（MMPs）的机制促进实验性腹主动脉瘤（AAA）的形成。最近，我们报道了白细胞介素（IL）-1β在小鼠实验性 AAA 形成中的主要作用。在此，我们检验了 IL-1β诱导的中性粒细胞胞外诱捕网形成（NETosis）促进 AAA 的假设。
通过免疫组织化学，使用中性粒细胞、Cit-H3（瓜氨酸化组蛋白 H3）和 DNA 的共定位染色来鉴定 NETs。在人类 AAA 中检测到 NETs，并与 IL-1β共定位。在体外，IL-1RA 减弱了 IL-1β诱导的人中性粒细胞的 NETosis。在机制上，IL-1β处理分离的中性粒细胞诱导鞘氨醇合酶 6 的核定位和 C16-神经酰胺的合成，IL-1RA 或鞘氨醇合成抑制剂 Fumonisin B1 可抑制这一过程。此外，IL-1RA 或 Fumonisin B1 减弱了 IL1-β诱导的 NETosis。在小鼠 AAA 的实验模型中，在动脉瘤诱导的第 3 天就检测到 NETs。IL-1β 敲除小鼠对主动脉的中性粒细胞浸润明显减少，并免受 AAA 的影响。野生型中性粒细胞的过继转移促进了 IL-1β 敲除小鼠的 AAA 形成。此外，NETosis 抑制剂 Cl-amidine 处理野生型小鼠显著减轻了 AAA 的形成，而 DNA 消化酶脱氧核糖核酸酶对 AAA 的形成没有影响。
总之，结果表明 IL-1β 诱导的 NETosis 在 AAA 的形成中起主导作用。
