Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.
Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA; Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, USA.
J Biol Chem. 2022 Mar;298(3):101710. doi: 10.1016/j.jbc.2022.101710. Epub 2022 Feb 10.
Coronavirus disease 2019 (COVID-19) is a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is broadly accepted that SARS-CoV-2 utilizes its spike protein to recognize the extracellular domain of angiotensin-converting enzyme 2 (ACE2) to enter cells for viral infection. However, other mechanisms of SARS-CoV-2 cell entry may occur. We show quantitatively that the SARS-CoV-2 spike protein also binds to the extracellular domain of broadly expressed integrin α5β1 with an affinity comparable to that of SARS-CoV-2 binding to ACE2. More importantly, we provide direct evidence that such binding promotes the internalization of SARS-CoV-2 into non-ACE2 cells in a manner critically dependent upon the activation of the integrin. Our data demonstrate an alternative pathway for the cell entry of SARS-CoV-2, suggesting that upon initial ACE2-mediated invasion of the virus in the respiratory system, which is known to trigger an immune response and secretion of cytokines to activate integrin, the integrin-mediated cell invasion of SARS-CoV-2 into the respiratory system and other organs becomes effective, thereby promoting further infection and progression of COVID-19.
2019 年冠状病毒病(COVID-19)是由严重急性呼吸系统综合征冠状病毒 2(SARS-CoV-2)引起的高度传染性疾病。人们普遍认为,SARS-CoV-2 利用其刺突蛋白识别血管紧张素转换酶 2(ACE2)的细胞外结构域,从而进入细胞进行病毒感染。然而,SARS-CoV-2 进入细胞的其他机制也可能发生。我们定量地表明,SARS-CoV-2 刺突蛋白也与广泛表达的整合素 α5β1 的细胞外结构域结合,亲和力可与 SARS-CoV-2 与 ACE2 的结合相媲美。更重要的是,我们提供了直接证据表明,这种结合以整合素激活为关键依赖性方式促进 SARS-CoV-2 进入非 ACE2 细胞的内化。我们的数据表明了 SARS-CoV-2 进入细胞的另一种途径,表明在病毒最初通过 ACE2 入侵呼吸系统后,众所周知,这会引发免疫反应和细胞因子的分泌以激活整合素,随后 SARS-CoV-2 通过整合素介导的细胞入侵呼吸系统和其他器官变得有效,从而促进 COVID-19 的进一步感染和进展。