LL-37 促进鼻息肉慢性鼻窦炎患者中性粒细胞胞外诱捕网的形成。
LL-37 promotes neutrophil extracellular trap formation in chronic rhinosinusitis with nasal polyps.
机构信息
Otorhinolaryngology Hospital, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Department of Otolaryngology, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China.
出版信息
Clin Exp Allergy. 2019 Jul;49(7):990-999. doi: 10.1111/cea.13408. Epub 2019 May 29.
BACKGROUND
Neutrophil accumulation has been observed in chronic rhinosinusitis with nasal polyps (CRSwNP). However, the functions of neutrophils are poorly understood. Neutrophils produce neutrophil extracellular traps (NETs), which are involved in a variety of chronic inflammatory pathologies. LL-37 is the only member of the cathelicidin family in human.
OBJECTIVE
Our aims were to examine the presence of NETs in CRSwNP and to investigate the regulatory effect of LL-37 on NET formation.
METHODS
Nasal polyp tissues were investigated for the presence of NETs by using immunofluorescent (IF) staining. The expression and distribution of LL-37 were examined by using quantitative RT-PCR, ELISA, IF, and immunohistochemistry. Purified peripheral neutrophils were stimulated with LL-37 and stained with IF to identify NETs. NETs% was defined as percentage of NET-generating neutrophils to the total number of neutrophils.
RESULTS
Neutrophil extracellular traps were located in the subepithelial layer of nasal polyps and control tissues. Nasal polyps had higher NETs% compared with that of controls (23.01% ± 3.43% vs 4.52% ± 1.33%, P < 0.0001). NET count was also increased in nasal polyps. NET count correlated with neutrophil count (r = 0.908, P < 0.001). LL-37 protein and mRNA levels were upregulated in nasal polyps. LL-37 was distributed in the epithelial and subepithelial layer and mainly expressed by neutrophils. Moreover, LL-37 promoted peripheral neutrophils to form NETs in a dose-dependent manner ex vivo. Interestingly, dexamethasone did not inhibit the effect of LL-37 on inducing NET formation. Furthermore, peripheral neutrophils from CRSwNP patients were more susceptible to LL-37-mediated NET formation, compared with neutrophils derived from control subjects. In addition, NETs released LL-37 in vivo and ex vivo.
CONCLUSION
Neutrophil extracellular traps are significantly increased in nasal polyps and LL-37 induces NET formation in CRSwNP patients. These findings indicate that NETs may contribute to the pathogenesis of neutrophilic inflammation in CRSwNP.
背景
中性粒细胞在慢性鼻-鼻窦炎伴鼻息肉（CRSwNP）中聚集。然而，中性粒细胞的功能尚未完全阐明。中性粒细胞产生中性粒细胞胞外诱捕网（NETs），这涉及多种慢性炎症性病理。LL-37 是人类唯一的抗菌肽家族成员。
目的
本研究旨在检测 CRSwNP 中 NETs 的存在，并研究 LL-37 对 NET 形成的调控作用。
方法
通过免疫荧光（IF）染色检测鼻息肉组织中 NETs 的存在。采用定量 RT-PCR、ELISA、IF 和免疫组化检测 LL-37 的表达和分布。用 LL-37 刺激纯化的外周血中性粒细胞，并用 IF 染色鉴定 NETs。NETs%定义为产生 NET 的中性粒细胞占总中性粒细胞的百分比。
结果
NETs 位于鼻息肉和对照组织的黏膜下层。与对照组相比，鼻息肉中的 NETs%更高（23.01%±3.43%比 4.52%±1.33%，P<0.0001）。鼻息肉中的 NET 计数也增加了。NET 计数与中性粒细胞计数呈正相关（r=0.908，P<0.001）。鼻息肉中 LL-37 蛋白和 mRNA 水平上调。LL-37 分布在上皮和黏膜下层，主要由中性粒细胞表达。此外，LL-37 以剂量依赖的方式在体外促进外周血中性粒细胞形成 NETs。有趣的是，地塞米松不能抑制 LL-37 诱导 NET 形成的作用。此外，与对照组相比，CRSwNP 患者的外周血中性粒细胞对 LL-37 介导的 NET 形成更敏感。此外，NETs 在体内和体外释放 LL-37。
结论
鼻息肉中 NETs 显著增加，LL-37 诱导 CRSwNP 患者形成 NETs。这些发现表明 NETs 可能有助于 CRSwNP 中性粒细胞炎症的发病机制。
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