由迄今未描述的机制引发的过度炎症是严重急性呼吸综合征冠状病毒2(SARS-CoV-2)感染的标志,并且与增强的致病性和死亡率相关。
补体过度激活促进肺损伤,并在中东呼吸综合征相关冠状病毒患者中观察到,SARS-CoV-1和SARS-CoV-2感染。因此,我们从补体成分3(C3)介导的作用方面研究了人气道上皮细胞在暴露于SARS-CoV-2时的首次相互作用。
为此,我们使用了感染SARS-CoV-2患者分离株的高分化原代人3维组织模型.关于感染,病毒载量,病毒感染性,细胞内补体激活,炎症机制,和组织破坏通过实时RT-PCR分析,高含量筛选,斑块检测,luminex分析,和跨上皮电阻测量。
这里,我们表明,原发性正常人支气管和小气道上皮细胞通过膨胀的局部C3动员对SARS-CoV-2感染作出反应。SARS-CoV-2感染导致细胞内补体激活过度,并破坏了单层培养的人气道细胞和高度分化的上皮完整性,伪分层,粘液产生,纤毛呼吸组织模型。SARS-CoV-2感染的3维培养物分泌的C3a和促炎细胞因子IL-6,单核细胞趋化蛋白1,IL-1α的水平显着升高,和RANTES。
最重要的是,我们在此首次说明,靶向非免疫呼吸细胞中的过敏毒素受体C3a受体和C5a受体可以预防内在肺部炎症和组织损伤.这为COVID-19的治疗开辟了令人兴奋的可能性。
Excessive inflammation triggered by a hitherto undescribed mechanism is a hallmark of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and is associated with enhanced pathogenicity and mortality.
Complement hyperactivation promotes lung injury and was observed in patients suffering from Middle East respiratory syndrome-related coronavirus, SARS-CoV-1, and SARS-CoV-2 infections. Therefore, we investigated the very first interactions of primary human airway epithelial cells on exposure to SARS-CoV-2 in terms of complement component 3 (C3)-mediated effects.
For this, we used highly differentiated primary human 3-dimensional tissue models infected with SARS-CoV-2 patient isolates. On infection, viral load, viral infectivity, intracellular complement activation, inflammatory mechanisms, and tissue destruction were analyzed by real-time RT-PCR, high content screening, plaque assays, luminex analyses, and transepithelial electrical resistance measurements.
Here, we show that primary normal human bronchial and small airway epithelial cells respond to SARS-CoV-2 infection by an inflated local C3 mobilization. SARS-CoV-2 infection resulted in exaggerated intracellular complement activation and destruction of the epithelial integrity in monolayer cultures of primary human airway cells and highly differentiated, pseudostratified, mucus-producing, ciliated respiratory tissue models. SARS-CoV-2-infected 3-dimensional cultures secreted significantly higher levels of C3a and the proinflammatory cytokines IL-6, monocyte chemoattractant protein 1, IL-1α, and RANTES.
Crucially, we illustrate here for the first time that targeting the anaphylotoxin receptors C3a receptor and C5a receptor in nonimmune respiratory cells can prevent intrinsic lung inflammation and tissue damage. This opens up the exciting possibility in the treatment of COVID-19.