Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands.
J Innate Immun. 2017;9(4):359-374. doi: 10.1159/000455193. Epub 2017 Feb 8.
Antimicrobial proteins and peptides (AMPs) are a central component of the antibacterial activity of airway epithelial cells. It has been proposed that a decrease in antibacterial lung defense contributes to an increased susceptibility to microbial infection in smokers and patients with chronic obstructive pulmonary disease (COPD). However, whether reduced AMP expression in the epithelium contributes to this lower defense is largely unknown. We investigated the bacterial killing activity and expression of AMPs by air-liquid interface-cultured primary bronchial epithelial cells from COPD patients and non-COPD (ex-)smokers that were stimulated with nontypeable Haemophilus influenzae (NTHi). In addition, the effect of cigarette smoke on AMP expression and the activation of signaling pathways was determined. COPD cell cultures displayed reduced antibacterial activity, whereas smoke exposure suppressed the NTHi-induced expression of AMPs and further increased IL-8 expression in COPD and non-COPD cultures. Moreover, smoke exposure impaired NTHi-induced activation of NF-κB, but not MAP-kinase signaling. Our findings demonstrate that the antibacterial activity of cultured airway epithelial cells induced by acute bacterial exposure was reduced in COPD and suppressed by cigarette smoke, whereas inflammatory responses persisted. These findings help to explain the imbalance between protective antibacterial and destructive inflammatory innate immune responses in COPD.
抗菌蛋白和肽 (AMPs) 是气道上皮细胞抗菌活性的核心组成部分。有人提出,抗菌肺防御功能下降导致吸烟者和慢性阻塞性肺疾病 (COPD) 患者对微生物感染的易感性增加。然而,上皮细胞中 AMP 表达的减少是否导致这种防御能力降低在很大程度上尚不清楚。我们通过气液界面培养 COPD 患者和非 COPD(ex-)吸烟者的原代支气管上皮细胞,研究了其对非定型流感嗜血杆菌 (NTHi) 的细菌杀伤活性和 AMP 表达。此外,还确定了香烟烟雾对 AMP 表达和信号通路激活的影响。COPD 细胞培养物显示出抗菌活性降低,而烟雾暴露抑制了 NTHi 诱导的 AMP 表达,并进一步增加了 COPD 和非 COPD 培养物中 IL-8 的表达。此外,烟雾暴露损害了 NTHi 诱导的 NF-κB 激活,但不影响 MAP-激酶信号通路。我们的研究结果表明,在 COPD 和香烟烟雾的抑制下,急性细菌暴露诱导的培养气道上皮细胞的抗菌活性降低,而炎症反应持续存在。这些发现有助于解释 COPD 中保护性抗菌和破坏性炎症固有免疫反应之间的失衡。