Nguyen H, Finkelstein E, Reznick A, Cross C, van der Vliet A
Center for Comparative Respiratory Biology and Medicine, Department of Internal Medicine, CCRBM, 1121 Surge I, University of California, Davis, CA 95616, USA.
Toxicology. 2001 Mar 7;160(1-3):207-17. doi: 10.1016/s0300-483x(00)00450-9.
Exposure to airborne pollutants such as tobacco smoke is associated with increased activation of inflammatory-immune processes and is thought to contribute to the incidence of respiratory tract disease. We hypothezised that cigarette smoke (CS) could synergize with activated inflammatory/immune cells to cause oxidative injury or result in the formation of unique reactive oxidants. Isolated human neutrophils were exposed to gas-phase CS, and the production of nitrating and chlorinating oxidants following neutrophil stimulation was monitored using the substrate 4-hydroxyphenylacetate (HPA). Stimulation of neutrophils in the presence of CS resulted in a reduced oxidation and chlorination of HPA, suggesting inhibition of NADPH oxidase or myeloperoxidase (MPO), the two major enzymes involved in inflammatory oxidant formation. Peroxidase assays demonstrated that neutrophil MPO activity was not significantly affected after CS-exposure, leaving the NADPH oxidase as a likely target. The inhibition of neutrophil oxidant formation was found to coincide with depletion of cellular GSH, and a similar modification of critical cysteine residues, such as those in NADPH oxidase components, might be involved in reduced respiratory burst activity. As alpha,beta-unsaturated aldehydes such as acrolein have been implicated in thiol modifications by CS, we exposed neutrophils to acrolein prior to stimulation, and observed inhibition of NADPH oxidase activation in relation to GSH depletion. Additionally, translocation of the cytosolic components of NADPH oxidase to the membrane, a necessary requirement for enzyme activation, was inhibited. Protein adducts of acrolein (or related aldehydes) could be detected in several neutrophil proteins, including NADPH oxidase components, following neutrophil exposure to either CS or acrolein. Alterations in neutrophil function by exposure to (environmental) tobacco smoke may affect inflammatory/infectious conditions and thereby contribute to tobacco-related disease.
暴露于诸如烟草烟雾等空气传播污染物与炎症免疫过程的激活增加相关，并且被认为会导致呼吸道疾病的发生。我们推测香烟烟雾（CS）可能与活化的炎症/免疫细胞协同作用，导致氧化损伤或形成独特的活性氧化剂。将分离的人中性粒细胞暴露于气相CS中，并使用底物4-羟基苯乙酸（HPA）监测中性粒细胞刺激后硝化和氯化氧化剂的产生。在CS存在下刺激中性粒细胞导致HPA的氧化和氯化减少，表明参与炎症氧化剂形成的两种主要酶，即NADPH氧化酶或髓过氧化物酶（MPO）受到抑制。过氧化物酶测定表明，CS暴露后中性粒细胞MPO活性没有受到显著影响，使得NADPH氧化酶成为可能的靶点。发现中性粒细胞氧化剂形成的抑制与细胞内谷胱甘肽（GSH）的消耗同时发生，并且关键半胱氨酸残基的类似修饰，例如NADPH氧化酶组分中的那些，可能参与呼吸爆发活性的降低。由于诸如丙烯醛等α，β-不饱和醛已被认为与CS引起的硫醇修饰有关，我们在刺激前将中性粒细胞暴露于丙烯醛，并观察到与GSH消耗相关的NADPH氧化酶激活受到抑制。此外，NADPH氧化酶的胞质组分向膜的转位，这是酶激活的必要条件，也受到抑制。在中性粒细胞暴露于CS或丙烯醛后，在几种中性粒细胞蛋白质中，包括NADPH氧化酶组分中，可以检测到丙烯醛（或相关醛）的蛋白质加合物。暴露于（环境）烟草烟雾对中性粒细胞功能的改变可能会影响炎症/感染状况，从而导致与烟草相关的疾病。
