Wu Qun, Jiang Di, Matsuda Jennifer L, Ternyak Kristina, Zhang Bicheng, Chu Hong Wei
1 Department of Medicine and.
2 Mouse Genetics Core Facility, National Jewish Health, Denver, Colorado.
Am J Respir Cell Mol Biol. 2016 Sep;55(3):429-38. doi: 10.1165/rcmb.2015-0143OC.
Cigarette smoke (CS)-induced airway epithelial senescence has been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD), although the underlying mechanisms remain largely unknown. Growth differentiation factor (GDF) 15 is increased in airway epithelium of smokers with COPD and CS-exposed human airway epithelial cells, but its role in CS-induced airway epithelial senescence is unclear. In this study, we first analyzed expression of GDF15 and cellular senescence markers in airway epithelial cells of current smokers and nonsmokers. Second, we determined the role of GDF15 in CS-induced airway epithelial senescence by using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) 9 genome editing approach. Finally, we examined whether exogenous GDF15 protein promoted airway epithelial senescence through the activin receptor-like kinase 1/Smad1 pathway. GDF15 up-regulation was found in parallel with increased cellular senescence markers, p21, p16, and high-mobility group box 1 in airway epithelial cells of current smokers compared with nonsmokers. Moreover, CS extract induced cellular senescence in cultured human airway epithelial cells, represented by induced senescence-associated β-galactosidase activity, inhibited cell proliferation, increased p21 expression, and increased release of high-mobility group box 1 and IL-6. Disruption of GDF15 significantly inhibited CS extract-induced airway epithelial senescence. Lastly, GDF15 protein bound to the activin receptor-like kinase 1 receptor and promoted airway epithelial senescence via activation of the Smad1 pathway. Our findings highlight an important contribution of GDF15 in promoting airway epithelial senescence upon CS exposure. Senescent airway epithelial cells that chronically accumulate in CS-exposed lungs could contribute substantially to chronic airway inflammation in COPD development and progression.
香烟烟雾（CS）诱导的气道上皮衰老与慢性阻塞性肺疾病（COPD）的发病机制有关，尽管其潜在机制在很大程度上仍不清楚。生长分化因子（GDF）15在患有COPD的吸烟者和暴露于CS的人气道上皮细胞中升高，但其在CS诱导的气道上皮衰老中的作用尚不清楚。在本研究中，我们首先分析了当前吸烟者和非吸烟者气道上皮细胞中GDF15和细胞衰老标志物的表达。其次，我们使用成簇规律间隔短回文重复序列（CRISPR）/CRISPR相关蛋白（Cas）9基因组编辑方法确定了GDF15在CS诱导的气道上皮衰老中的作用。最后，我们研究了外源性GDF15蛋白是否通过激活素受体样激酶1/Smad1途径促进气道上皮衰老。与非吸烟者相比，当前吸烟者气道上皮细胞中GDF15上调与细胞衰老标志物p21、p16和高迁移率族蛋白B1增加同时出现。此外，CS提取物在培养的人气道上皮细胞中诱导细胞衰老，表现为诱导衰老相关β-半乳糖苷酶活性、抑制细胞增殖、增加p21表达以及增加高迁移率族蛋白B1和IL-6的释放。破坏GDF15可显著抑制CS提取物诱导的气道上皮衰老。最后，GDF15蛋白与激活素受体样激酶1受体结合，并通过激活Smad1途径促进气道上皮衰老。我们的研究结果突出了GDF15在CS暴露后促进气道上皮衰老中的重要作用。长期积聚在暴露于CS的肺部的衰老气道上皮细胞可能在COPD的发生和发展中对慢性气道炎症有很大贡献。
