Irish Centre for Genetic Lung Disease, Royal College of Surgeons in Ireland, Dublin 9, Ireland.
National Institute for Cellular Biotechnology, Dublin City University, Glasnevin, Dublin 9, Ireland; and.
Am J Respir Cell Mol Biol. 2022 Jul;67(1):76-88. doi: 10.1165/rcmb.2021-0433OC.
Alpha-1 antitrypsin deficiency (AATD) is characterized by neutrophil-dominated inflammation resulting in emphysema. The cholesterol-rich neutrophil outer plasma membrane plays a central role in adhesion and subsequent transmigration to underlying tissues. This study aimed to investigate mechanisms of increased neutrophil adhesion in AATD and whether alpha-1 antitrypsin (AAT) augmentation therapy abrogates this effect. Plasma and blood neutrophils were donated by healthy controls ( = 20), AATD ( = 30), and AATD patients after AAT augmentation therapy ( = 6). Neutrophil membrane protein expression was investigated using liquid chromatography-tandem mass spectrometry. The effect of once-weekly intravenous AAT augmentation therapy was assessed by calcium fluorometric, μ-calpain, and cell adhesion assays. Decreased neutrophil plasma membrane cholesterol content ( = 0.03), yet increased abundance of integrin α-M (fold change 1.91), integrin α-L (fold change 3.76), and cytoskeletal adaptor proteins including talin-1 (fold change 4.04) were detected on AATD neutrophil plasma membrane fractions. The described inflammatory induced structural changes were a result of a more than twofold increased cytosolic calcium concentration ( = 0.02), leading to significant calcium-dependent μ-calpain activity (3.5-fold change; = 0.005), resulting in proteolysis of the membrane cholesterol trafficking protein caveolin-1. Treatment of AAT-deficient individuals with AAT augmentation therapy resulted in increased caveolin-1 and membrane cholesterol content (111.8 ± 15.5 vs. 64.18 ± 7.8 μg/2 × 10 cells before and after treatment, respectively; = 0.02), with concurrent decreased neutrophil integrin expression and adhesion. Results demonstrate an auxiliary benefit of AAT augmentation therapy, evident by a decrease in circulating inflammation and controlled neutrophil adhesion.
α-1 抗胰蛋白酶缺乏症（AATD）的特征是中性粒细胞主导的炎症导致肺气肿。富含胆固醇的中性粒细胞外质膜在粘附和随后向基底组织迁移中起核心作用。本研究旨在探讨 AATD 中中性粒细胞粘附增加的机制，以及α-1 抗胰蛋白酶（AAT）增强疗法是否会消除这种作用。健康对照者（ = 20）、AATD 患者（ = 30）和接受 AAT 增强治疗后的 AATD 患者（ = 6）捐赠了血浆和血液中性粒细胞。使用液相色谱-串联质谱法研究中性粒细胞膜蛋白表达。通过钙荧光、μ-钙蛋白酶和细胞粘附测定评估每周一次静脉内 AAT 增强治疗的效果。在 AATD 中性粒细胞质膜部分检测到中性粒细胞血浆膜胆固醇含量降低（ = 0.03），但整合素 α-M（倍数变化 1.91）、整合素 α-L（倍数变化 3.76）和细胞骨架衔接蛋白的丰度增加，包括 talin-1（倍数变化 4.04）。描述的炎症诱导的结构变化是由于细胞浆钙离子浓度增加两倍以上（ = 0.02），导致显著的钙依赖性 μ-钙蛋白酶活性（倍数变化 3.5； = 0.005），导致膜胆固醇转运蛋白 caveolin-1 的蛋白水解。用 AAT 增强疗法治疗 AAT 缺乏个体导致 caveolin-1 和质膜胆固醇含量增加（治疗前后分别为 111.8 ± 15.5 和 64.18 ± 7.8 μg/2 × 10 细胞； = 0.02），同时中性粒细胞整合素表达和粘附减少。结果表明，AAT 增强治疗具有辅助益处，表现为循环炎症减少和控制中性粒细胞粘附。
