Abstract：
BACKGROUND: Altered complement component 3 (C3) activation in patients with alpha-1 antitrypsin (AAT) deficiency (AATD) has been reported. To understand the potential impact on course of inflammation, the aim of this study was to investigate whether C3d, a cleavage-product of C3, triggers interleukin (IL)-1β secretion via activation of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome. The objective was to explore the effect of AAT augmentation therapy in patients with AATD on the C3d/complement receptor 3 (CR3) signalling axis of monocytes and on circulating pro-inflammatory markers.
METHODS: Inflammatory mediators were detected in blood from patients with AATD (n=28) and patients with AATD receiving augmentation therapy (n=19). Inflammasome activation and IL-1β secretion were measured in monocytes of patients with AATD, and following C3d stimulation in the presence or absence of CR3 or NLRP3 inhibitors.
RESULTS: C3d acting via CR3 induces NLRP3 and pro-IL-1β production, and through induction of endoplasmic reticulum (ER) stress and calcium flux, triggers caspase-1 activation and IL-1β secretion. Treatment of individuals with AATD with AAT therapy results in decreased plasma levels of C3d (3.0±1.2 µg/mL vs 1.3±0.5 µg/mL respectively, p<0.0001) and IL-1β (115.4±30 pg/mL vs 73.3±20 pg/mL, respectively, p<0.0001), with a 2.0-fold decrease in monocyte NLRP3 protein expression (p=0.0303), despite continued ER stress activation.
CONCLUSIONS: These results provide strong insight into the mechanism of complement-driven inflammation associated with AATD. Although the described variance in C3d and NLRP3 activation decreased post AAT augmentation therapy, results demonstrate persistent C3d and monocyte ER stress, with implications for new therapeutics and clinical practice.
METHODS: Inflammatory mediators were detected in blood from patients with AATD (n=28) and patients with AATD receiving augmentation therapy (n=19). Inflammasome activation and IL-1β secretion were measured in monocytes of patients with AATD, and following C3d stimulation in the presence or absence of CR3 or NLRP3 inhibitors.
RESULTS: C3d acting via CR3 induces NLRP3 and pro-IL-1β production, and through induction of endoplasmic reticulum (ER) stress and calcium flux, triggers caspase-1 activation and IL-1β secretion. Treatment of individuals with AATD with AAT therapy results in decreased plasma levels of C3d (3.0±1.2 µg/mL vs 1.3±0.5 µg/mL respectively, p<0.0001) and IL-1β (115.4±30 pg/mL vs 73.3±20 pg/mL, respectively, p<0.0001), with a 2.0-fold decrease in monocyte NLRP3 protein expression (p=0.0303), despite continued ER stress activation.
CONCLUSIONS: These results provide strong insight into the mechanism of complement-driven inflammation associated with AATD. Although the described variance in C3d and NLRP3 activation decreased post AAT augmentation therapy, results demonstrate persistent C3d and monocyte ER stress, with implications for new therapeutics and clinical practice.
摘要：
背景：已经报道了α-1抗胰蛋白酶（AAT）缺乏症（AATD）患者中补体成分3（C3）激活的改变。为了了解对炎症过程的潜在影响，这项研究的目的是调查C3d，C3的切割产物，通过激活NOD-，触发白细胞介素（IL）-1β分泌，含有LRR和pyrin结构域的蛋白3(NLRP3)炎性体。目的是探讨AAT增强疗法对AATD患者单核细胞C3d/补体受体3（CR3）信号轴和循环促炎标志物的影响。
方法：在AATD患者（n=28）和接受强化治疗的AATD患者（n=19）的血液中检测到炎症介质。在AATD患者的单核细胞中测量炎症小体激活和IL-1β分泌，以及在存在或不存在CR3或NLRP3抑制剂的情况下的C3d刺激之后。
结果：通过CR3作用的C3d诱导NLRP3和pro-IL-1β的产生，并通过诱导内质网（ER）应激和钙通量，触发caspase-1激活和IL-1β分泌。用AAT治疗AATD个体导致血浆C3d水平降低（分别为3.0±1.2µg/mL和1.3±0.5µg/mL，p<0.0001）和IL-1β（115.4±30pg/mLvs73.3±20pg/mL，分别,p<0.0001),单核细胞NLRP3蛋白表达减少2.0倍（p=0.0303），尽管持续的ER压力激活。
结论：这些结果对补体驱动的与AATD相关的炎症机制提供了强有力的见解。尽管在AAT增强治疗后C3d和NLRP3激活的所述变化减少，结果表明持续的C3d和单核细胞内质网应激，对新疗法和临床实践的影响。
方法：在AATD患者（n=28）和接受强化治疗的AATD患者（n=19）的血液中检测到炎症介质。在AATD患者的单核细胞中测量炎症小体激活和IL-1β分泌，以及在存在或不存在CR3或NLRP3抑制剂的情况下的C3d刺激之后。
结果：通过CR3作用的C3d诱导NLRP3和pro-IL-1β的产生，并通过诱导内质网（ER）应激和钙通量，触发caspase-1激活和IL-1β分泌。用AAT治疗AATD个体导致血浆C3d水平降低（分别为3.0±1.2µg/mL和1.3±0.5µg/mL，p<0.0001）和IL-1β（115.4±30pg/mLvs73.3±20pg/mL，分别,p<0.0001),单核细胞NLRP3蛋白表达减少2.0倍（p=0.0303），尽管持续的ER压力激活。
结论：这些结果对补体驱动的与AATD相关的炎症机制提供了强有力的见解。尽管在AAT增强治疗后C3d和NLRP3激活的所述变化减少，结果表明持续的C3d和单核细胞内质网应激，对新疗法和临床实践的影响。
