Department of Immunology, School of Medicine, University of Connecticut Health Center, Farmington, CT, 06030, USA.
Mil Med Res. 2021 Sep 7;8(1):49. doi: 10.1186/s40779-021-00340-5.
Retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated protein 5 (MDA5) sense viral RNA and activate antiviral immune responses. Herein we investigate their functions in human epithelial cells, the primary and initial target of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A deficiency in MDA5, RIG-I or mitochondrial antiviral signaling protein (MAVS) enhanced viral replication. The expression of the type I/III interferon (IFN) during infection was impaired in MDA5 and MAVS, but not in RIG-I, when compared to wild type (WT) cells. The mRNA level of full-length angiotensin-converting enzyme 2 (ACE2), the cellular entry receptor for SARS-CoV-2, was ~ 2.5-fold higher in RIG-I than WT cells. These data demonstrate MDA5 as the predominant SARS-CoV-2 sensor, IFN-independent induction of ACE2 and anti-SARS-CoV-2 role of RIG-I in epithelial cells.
视黄酸诱导基因 I(RIG-I)和黑色素瘤分化相关蛋白 5(MDA5)可识别病毒 RNA 并激活抗病毒免疫反应。在此,我们研究了它们在人上皮细胞中的功能,人上皮细胞是严重急性呼吸综合征冠状病毒 2(SARS-CoV-2)的主要初始靶细胞。与野生型(WT)细胞相比,MDA5、RIG-I 或线粒体抗病毒信号蛋白(MAVS)缺陷会增强病毒复制。与 WT 细胞相比,MDA5 和 MAVS 中的 I/III 型干扰素(IFN)的表达在感染过程中受到抑制,但 RIG-I 中不受抑制。全长血管紧张素转换酶 2(ACE2)的 mRNA 水平,即 SARS-CoV-2 的细胞进入受体,在 RIG-I 细胞中比 WT 细胞高约 2.5 倍。这些数据表明 MDA5 是 SARS-CoV-2 的主要传感器,IFN 独立诱导 ACE2 的产生,以及 RIG-I 在上皮细胞中抗 SARS-CoV-2 的作用。