Yao Hongwei, Sundar Isaac K, Huang Yadi, Gerloff Janice, Sellix Michael T, Sime Patricia J, Rahman Irfan
Departments of 1 Environmental Medicine, Lung Biology and Disease Program.
2 Medicine, Division of Endocrinology, Diabetes and Metabolism; and.
Am J Respir Cell Mol Biol. 2015 Dec;53(6):782-92. doi: 10.1165/rcmb.2014-0474OC.
Chronic obstructive pulmonary disease (COPD) is the fourth most common cause of death, and it is characterized by abnormal inflammation and lung function decline. Although the circadian molecular clock regulates inflammatory responses, there is no information available regarding the impact of COPD on lung molecular clock function and its regulation by sirtuin 1 (SIRT1). We hypothesize that the molecular clock in the lungs is disrupted, leading to increased inflammatory responses in smokers and patients with COPD and its regulation by SIRT1. Lung tissues, peripheral blood mononuclear cells (PBMCs), and sputum cells were obtained from nonsmokers, smokers, and patients with COPD for measurement of core molecular clock proteins (BMAL1, CLOCK, PER1, PER2, and CRY1), clock-associated nuclear receptors (REV-ERBα, REV-ERBβ, and RORα), and SIRT1 by immunohistochemistry, immunofluorescence, and immunoblot. PBMCs were treated with the SIRT1 activator SRT1720 followed by LPS treatment, and supernatant was collected at 6-hour intervals. Levels of IL-8, IL-6, and TNF-α released from PBMCs were determined by ELISA. Expression of BMAL1, PER2, CRY1, and REV-ERBα was reduced in PBMCs, sputum cells, and lung tissues from smokers and patients with COPD when compared with nonsmokers. SRT1720 treatment attenuated LPS-mediated reduction of BMAL1 and REV-ERBα in PBMCs from nonsmokers. Additionally, LPS differentially affected the timing and amplitude of cytokine (IL-8, IL-6, and TNF-α) release from PBMCs in nonsmokers, smokers, and patients with COPD. Moreover, SRT1720 was able to inhibit LPS-induced cytokine release from cultured PBMCs. In conclusion, disruption of the molecular clock due to SIRT1 reduction contributes to abnormal inflammatory response in smokers and patients with COPD.
慢性阻塞性肺疾病（COPD）是第四大常见死因，其特征为异常炎症和肺功能下降。尽管昼夜分子时钟调节炎症反应，但关于COPD对肺分子时钟功能的影响及其受沉默调节蛋白1（SIRT1）调控的信息尚不可得。我们推测，肺中的分子时钟被破坏，导致吸烟者和COPD患者的炎症反应增加，且受SIRT1调控。从非吸烟者、吸烟者和COPD患者获取肺组织、外周血单核细胞（PBMC）和痰液细胞，通过免疫组织化学、免疫荧光和免疫印迹法检测核心分子时钟蛋白（BMAL1、CLOCK、PER1、PER2和CRY1）、时钟相关核受体（REV-ERBα、REV-ERBβ和RORα）以及SIRT1。用SIRT1激活剂SRT1720处理PBMC，随后进行LPS处理，每隔6小时收集上清液。通过ELISA测定PBMC释放的IL-8、IL-6和TNF-α水平。与非吸烟者相比，吸烟者和COPD患者的PBMC、痰液细胞和肺组织中BMAL1、PER2、CRY1和REV-ERBα的表达降低。SRT1720处理减弱了LPS介导的非吸烟者PBMC中BMAL1和REV-ERBα的减少。此外，LPS对非吸烟者、吸烟者和COPD患者PBMC中细胞因子（IL-8、IL-6和TNF-α）释放的时间和幅度有不同影响。而且，SRT1720能够抑制LPS诱导的培养PBMC中细胞因子的释放。总之，由于SIRT1减少导致的分子时钟破坏促成了吸烟者和COPD患者的异常炎症反应。
