Department I of Internal Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany.
Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and University Hospital Cologne, University of Cologne, Robert-Koch-Strasse 21, 50931 Cologne, Germany.
Viruses. 2021 Oct 15;13(10):2076. doi: 10.3390/v13102076.
Infections with viral pathogens are widespread and can cause a variety of different diseases. In-depth knowledge about viral triggers initiating an immune response is necessary to decipher viral pathogenesis. Inflammasomes, as part of the innate immune system, can be activated by viral pathogens. However, viral structural components responsible for inflammasome activation remain largely unknown. Here we analyzed glycoproteins derived from SARS-CoV-1/2, HCMV and HCV, required for viral entry and fusion, as potential triggers of NLRP3 inflammasome activation and pyroptosis in THP-1 macrophages. All tested glycoproteins were able to potently induce NLRP3 inflammasome activation, indicated by ASC-SPECK formation and secretion of cleaved IL-1β. Lytic cell death via gasdermin D (GSDMD), pore formation, and pyroptosis are required for IL-1β release. As a hallmark of pyroptosis, we were able to detect cleavage of GSDMD and, correspondingly, cell death in THP-1 macrophages. CRISPR-Cas9 knockout of NLRP3 and GSDMD in THP-1 macrophages confirmed and strongly support the evidence that viral glycoproteins can act as innate immunity triggers. With our study, we decipher key mechanisms of viral pathogenesis by showing that viral glycoproteins potently induce innate immune responses. These insights could be beneficial in vaccine development and provide new impulses for the investigation of vaccine-induced innate immunity.
病毒病原体的感染非常普遍，可导致多种不同的疾病。深入了解引发免疫反应的病毒触发因素对于解析病毒发病机制是必要的。作为先天免疫系统的一部分，炎症小体可以被病毒病原体激活。然而，负责炎症小体激活的病毒结构成分在很大程度上仍然未知。在这里，我们分析了 SARS-CoV-1/2、HCMV 和 HCV 病毒进入和融合所需的糖蛋白，作为 NLRP3 炎症小体激活和 THP-1 巨噬细胞焦亡的潜在触发因素。所有测试的糖蛋白都能够强烈诱导 NLRP3 炎症小体的激活，表现为 ASC-SPECK 形成和裂解的 IL-1β 的分泌。通过 gasdermin D (GSDMD) 裂解、孔形成和焦亡导致细胞溶解死亡，这是 IL-1β 释放所必需的。作为焦亡的标志，我们能够检测到 GSDMD 的裂解，以及相应的 THP-1 巨噬细胞死亡。THP-1 巨噬细胞中 NLRP3 和 GSDMD 的 CRISPR-Cas9 敲除证实并强烈支持了病毒糖蛋白可以作为先天免疫触发物的证据。通过我们的研究，我们通过显示病毒糖蛋白能够强烈诱导先天免疫反应来解析病毒发病机制的关键机制。这些见解可能有益于疫苗开发，并为研究疫苗诱导的先天免疫提供新的动力。
