Molecular Respiratory Research Laboratory, Chest Research Foundation, Sr. No 15, Marigold Premises, Behind Gold Adlabs, Pune, Pune, 411014, Maharashtra, India.
Respir Res. 2019 Jul 30;20(1):171. doi: 10.1186/s12931-019-1139-2.
Metabolic adaptation in immune cells is necessary to modulate immune cell function as it is intricately coupled with intracellular metabolism. We aimed to characterize the metabolic state of human peripheral blood mononuclear cells (PBMCs) after long-term exposure to tobacco smoke in smokers with preserved lung function and COPD subjects.
PBMCs were isolated from healthy non-smokers (HNS), healthy smokers (HS) and COPD subjects, cultured and the mitochondrial respiration while utilizing glucose (glycolysis), fatty acids (β-oxidation) or pyruvate (direct Krebs' cycle substrate) was measured using the XFp Extracellular Flux Analyzer. Plasma levels of inflammatory cytokines IFN-γ, IL-17, TNF-α, IL-5, IL-9 and IFN-α were measured using flow cytometry. RAW264.7 cells were exposed to cigarette smoke condensate (CSC) for 1 h and its effect on cell viability, cellular metabolism and phagocytosis ability were also studied. Patient's data was analyzed using the Mann Whitney U test, whereas Student's t test was performed to analyze the in-vitro data.
PBMCs from COPD subjects showed a significant decrease in extracellular acidification rate (ECAR) while utilizing glucose as compared to HNS (151.9 Vs 215%). Mitochondrial oxygen consumption rate (OCR) on palmitate or pyruvate was also found to be significantly lower in COPD subjects as compared to HS and a strong positive correlation between palmitate OCR in PBMCs and FEV (r = 0.74, p < 0.05) and FVC (r = 0.79, p < 0.05) values in HS was observed. The metabolic shift towards fatty acid metabolism in healthy smokers promoted an inflammatory cytokine response with a greater increase in the levels of IL-5, IL-9 and IFN-α as compared to IFN-γ, IL-17 and TNF-α. In-vitro experiments with RAW 264.7 cells showed similar metabolic alterations and a reduced ability to phagocytose Streptococcus pneumonia and Haemophilus influenza after cigarette smoke exposure in the presence of glucose or palmitate.
These findings indicate a metabolic basis for the inflammatory response in COPD and could suggest a new therapeutic target for controlling the immune response and delaying the onset of disease.
This observational study was retrospectively registered in the Clinical Trails Registry - India (ICMR - NIMS) on 19th January 2018 with the registration number CTRI/2018/01/011441 .
免疫细胞的代谢适应对于调节免疫细胞功能是必要的，因为它与细胞内代谢密切相关。我们旨在描述在肺功能正常的吸烟者和 COPD 患者中，长期暴露于烟草烟雾后，人外周血单核细胞（PBMC）的代谢状态。
从健康不吸烟者（HNS）、健康吸烟者（HS）和 COPD 患者中分离 PBMC，培养并利用 XFp 细胞外通量分析仪测量利用葡萄糖（糖酵解）、脂肪酸（β-氧化）或丙酮酸（直接三羧酸循环底物）时的线粒体呼吸。使用流式细胞术测量血浆中炎症细胞因子 IFN-γ、IL-17、TNF-α、IL-5、IL-9 和 IFN-α 的水平。RAW264.7 细胞暴露于香烟烟雾冷凝物（CSC） 1 小时，还研究了其对细胞活力、细胞代谢和吞噬能力的影响。使用 Mann Whitney U 检验分析患者数据，而使用 Student t 检验分析体外数据。
与 HNS 相比，COPD 患者的 PBMC 利用葡萄糖时的细胞外酸化率（ECAR）明显降低（151.9 比 215%）。利用棕榈酸或丙酮酸时的线粒体耗氧率（OCR）也发现 COPD 患者明显低于 HS，并且 HS 中棕榈酸 PBMC 的 OCR 与 FEV（r=0.74，p<0.05）和 FVC（r=0.79，p<0.05）值之间存在很强的正相关关系。健康吸烟者中脂肪酸代谢的代谢转变促进了炎症细胞因子的反应，与 IFN-γ、IL-17 和 TNF-α相比，IL-5、IL-9 和 IFN-α 的水平有更大的增加。体外实验表明，RAW 264.7 细胞在葡萄糖或棕榈酸存在下暴露于香烟烟雾后，代谢发生类似改变，吞噬肺炎链球菌和流感嗜血杆菌的能力降低。
这些发现表明 COPD 中炎症反应的代谢基础，并可能为控制免疫反应和延迟疾病发作提供新的治疗靶点。
本观察性研究于 2018 年 1 月 19 日在印度临床试验注册中心（ICMR-NIMS）进行了回顾性登记，注册号为 CTRI/2018/01/011441。
