Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, MI, 48109, United States; Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109, United States.
Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109, United States; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, United States.
Biomaterials. 2020 Apr;238:119836. doi: 10.1016/j.biomaterials.2020.119836. Epub 2020 Feb 3.
Neutrophil elastase (NE) is a serine protease stored in the azurophilic granules of neutrophils and released into the extracellular milieu during inflammatory response or formation of neutrophil extracellular traps (NETs). Neutrophils release NETs to entrap pathogens by externalizing their cellular contents in a DNA framework decorated with anti-microbials and proteases, including NE. Importantly, excess NETs in tissues are implicated in numerous pathologies, including sepsis, rheumatoid arthritis, vasculitis, and cancer. However, it remains unknown how to effectively prevent NET formation. Here, we show that NE plays a major role during NET formation and that inhibition of NE is a promising approach for decreasing NET-mediated tissue injury. NE promoted NET formation by human neutrophils. Whereas sivelestat, a small molecule inhibitor of NE, inhibited the formation of NETs in vitro , administration of free sivelestat did not have any efficacy in a murine model of lipopolysaccharide-induced endotoxic shock. To improve the efficacy of sivelestat in vivo, we have developed a nanoparticle system for delivering sivelestat. We demonstrate that nanoparticle-mediated delivery of sivelestat effectively inhibited NET formation, decreased the clinical signs of lung injury, reduced NE and other proinflammatory cytokines in serum, and rescued animals against endotoxic shock. Collectively, our data demonstrates that NE signaling can initiate NET formation and that nanoparticle-mediated inhibition of NE improves drug efficacy for preventing NET formation.
中性粒细胞弹性蛋白酶 (NE) 是一种丝氨酸蛋白酶，储存在中性粒细胞的嗜天青颗粒中，并在炎症反应或中性粒细胞胞外陷阱 (NETs) 形成过程中释放到细胞外环境中。中性粒细胞通过将其细胞内容物外化到带有抗微生物剂和蛋白酶（包括 NE）的 DNA 支架上来捕获病原体，从而释放 NETs。重要的是，组织中过多的 NETs 与许多病理学有关，包括败血症、类风湿关节炎、血管炎和癌症。然而，目前尚不清楚如何有效预防 NET 的形成。在这里，我们表明 NE 在 NET 的形成中起主要作用，并且抑制 NE 是减少 NET 介导的组织损伤的有前途的方法。NE 促进人中性粒细胞形成 NET。虽然 sivelestat 是一种 NE 的小分子抑制剂，可抑制体外 NET 的形成，但游离 sivelestat 在脂多糖诱导的内毒素休克的小鼠模型中没有任何疗效。为了提高 sivelestat 在体内的疗效，我们开发了一种用于输送 sivelestat 的纳米颗粒系统。我们证明，纳米颗粒介导的 sivelestat 输送可有效抑制 NET 的形成，减少肺损伤的临床症状，降低血清中的 NE 和其他促炎细胞因子，并使动物免受内毒素休克的影响。总之，我们的数据表明 NE 信号可以启动 NET 的形成，并且纳米颗粒介导的 NE 抑制可提高预防 NET 形成的药物疗效。
