SARS-CoV-2 uses major endothelial integrin αvβ3 to cause vascular dysregulation in-vitro during COVID-19

Abstract

The unprecedented global COVID-19 pandemic has prompted a desperate international effort to accelerate the development of anti-viral candidates. For unknown reasons, COVID-19 infections are associated with adverse cardiovascular complications, implicating that vascular endothelial cells are essential in viral propagation. The etiological pathogen, SARS-CoV-2, has a higher reproductive number and infection rate than its predecessors, indicating it possesses novel characteristics that infers enhanced transmissibility. A unique K403R spike protein substitution encodes an Arg-Gly-Asp (RGD) motif, introducing a potential role for RGD-binding host integrins. Integrin αVβ3 is widely expressed across the host, particularly in the endothelium, which acts as the final barrier before microbial entry into the bloodstream. This mutagenesis creates an additional binding site, which may be sufficient to increase SARS-CoV-2 pathogenicity. Here, we investigate how SARS-CoV-2 passes from the epithelium to endothelium, the effects of αVβ3 antagonist, Cilengitide, on viral adhesion, vasculature permeability and leakage, and also report on a simulated interaction between the viral and host protein in-silico.

Can the SARS-CoV-2 Spike Protein Bind Integrins Independent of the RGD Sequence?

“…Binding assays have shown that the spike protein directly interacts with α 5 β 1 and α V β 3 integrins ( Beddingfield et al, 2021 ; Nader et al, 2021 )⁠. One study discovered that the ATN-161 pentapeptide inhibited interactions between integrin α 5 β 1 and the SARS-CoV-2 spike protein, for which they predicted three inhibitory ATN-161 binding sites on α 5 β 1 ( Beddingfield et al, 2021 ).…”

“…The Severe Acute Syndrome Coronavirus 2 (SARS-CoV-2) spike protein receptor-binding domain, which binds to angiotensin-converting enzyme 2 (ACE2) to initiate viral cell entry, has been shown to contain an exposed RGD motif that has been suggested to be integrin-binding, thus potentially allowing for integrin-mediated cell entry ( Luan et al, 2020 ; Makowski et al, 2021 ). Experimental studies have shown that the SARS-CoV-2 spike protein directly binds α V β 3 and α 5 β 1 integrins and may also interact with α 3 , β 1 , α 4 , and α X integrin subunits ( Aguirre et al, 2020 ; Kotani and Nakano, 2020 ; Beddingfield et al, 2021 ; Nader et al, 2021 ; Wang et al, 2021 ). RGD-based drugs were found to inhibit spike binding to α V β 3 and α 5 β 1 integrins, and mutating the RGD motif to RGE or RGA was also found to decrease binding to α V β 5 integrins – further implicating the spike RGD motif in interactions with integrins ( Sebé-Pedrós et al, 2010 ; Robles et al, 2021 )⁠.…”

DataSheet_1.xlsx

“…Binding assays have shown that the spike protein directly interacts with a 5 b 1 and a V b 3 integrins (Beddingfield et al, 2021;Nader et al, 2021). One study discovered that the ATN-161 pentapeptide inhibited interactions between integrin a 5 b 1 and the SARS-CoV-2 spike protein, for which they predicted three inhibitory ATN-161 binding sites on a 5 b 1 (Beddingfield et al, 2021).…”

“…One study discovered that the ATN-161 pentapeptide inhibited interactions between integrin a 5 b 1 and the SARS-CoV-2 spike protein, for which they predicted three inhibitory ATN-161 binding sites on a 5 b 1 (Beddingfield et al, 2021). Cilengitide, an RGD-based drug, and an RGD peptide were found to block the SARS-CoV-2 spike protein from binding to a V b 3 and a 5 b 1 integrins, respectively, indicating that the spike protein binds in an RGD-dependent manner (Nader et al, 2021;Robles et al, 2021). A co-immunoprecipitation study found that mutating the RGD sequence to RGE or RGA reduced the binding of the SARS-CoV-2 spike protein to a V b 5 integrins (Gao et al, 2021).…”

“…The Severe Acute Syndrome Coronavirus 2 (SARS-CoV-2) spike protein receptor-binding domain, which binds to angiotensin-converting enzyme 2 (ACE2) to initiate viral cell entry, has been shown to contain an exposed RGD motif that has been suggested to be integrin-binding, thus potentially allowing for integrin-mediated cell entry (Luan et al, 2020;Makowski et al, 2021). Experimental studies have shown that the SARS-CoV-2 spike protein directly binds a V b 3 and a 5 b 1 integrins and may also interact with a 3 , b 1 , a 4 , and a X integrin subunits (Aguirre et al, 2020;Kotani and Nakano, 2020;Beddingfield et al, 2021;Nader et al, 2021;Wang et al, 2021). RGD-based drugs were found to inhibit spike binding to a V b 3 and a 5 b 1 integrins, and mutating the RGD motif to RGE or RGA was also found to decrease binding to a V b 5 integrinsfurther implicating the spike RGD motif in interactions with integrins (Sebe-Pedroś et al, 2010;Robles et al, 2021).…”