In the context of SARS-CoV-2 research, several studies have used high-throughput target-based (i.e., against spike, M pro) or phenotypic screens, as well as in silico studies, to identify inhibitors of SARS-CoV-2 infection. Repurposing existing drugs is the most rapid path to clinical intervention for emerging diseases. Independently of this secondary mechanism for entry, the SARS-CoV-2 spike receptor binding domain (RBD) was found to have a higher affinity for ACE2 than the SARS-CoV spike RBD, making it an ideal target to block the attachment of virus to host cells for drug discovery ( 4, 6).
This process may be facilitated by the preactivation of the spike protein by furin, which reduces the dependence of SARS-CoV-2 on TMPRSS2 for entry. Upon binding to ACE2, the SARS-CoV-2 spike protein needs to be activated by cellular proteases, such as TMPRSS2, to initiate the spike-mediated fusion of the viral envelope with the host-cell membrane ( 4, 6). SARS-CoV-2 engages the ACE2 receptor with higher-affinity binding than SARS-CoV-1 ( 5). SARS-CoV-2 is closely related to severe acute respiratory syndrome coronavirus (SARS-CoV-1) ( 3), and recent studies have demonstrated that the SARS-CoV-2 spike protein, like SARS-CoV-1, uses the angiotensin converting enzyme 2 (ACE2) as a cellular receptor to engage with host cells ( 4). The entry-blocking approach has been targeted with therapeutic antibodies ( 2) however, this approach targets the SARS-CoV-2 spike protein, whereas drugs have the potential to also target the host receptor for the virus. Inhibiting viral entry into host cells via blocking access to cell surface viral receptors can also be a successful strategy, the best example being the entry inhibitor drug maraviroc, which binds to the human immunodeficiency virus 1 (HIV-1) coreceptor CCR5 to block infection ( 1).
Most antiviral drug strategies target viral proteins or host factors required for intracellular replicative processes. The current pandemic caused by SARS-CoV-2 is a health emergency that requires the development of new vaccines and drugs to prevent or treat this disease. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a recently emerged virus that causes an often-fatal respiratory disease, COVID-19. This study has identified potential drugs for repurposing as SARS-CoV-2 entry inhibitors or as chemical scaffolds for drug development. Three compounds demonstrated dose-dependent antiviral in vitro potency-Evans blue, sodium lifitegrast, and lumacaftor.
A Vero-E6 cell-based SARS-CoV-2 infection assay was used to evaluate infection blockade by candidate entry inhibitors. These compounds included registered drugs and dyes used in biomedical applications. Twelve ACE2 binders and six of the RBD binders compete with the RBD-ACE2 interaction in an SPR-based competition assay. These combined screens identified compounds from these libraries that bind at K D (equilibrium dissociation constant) <3 μM affinity to their respective targets, 17 for ACE2 and 6 for SARS-CoV-2 RBD. SPR screening used immobilized human ACE2 and SARS-CoV-2 Spike protein to evaluate the binding of these proteins to a library of 3,141 compounds. Molecular modeling screening interrogated 57,641 compounds and focused on the region of ACE2 that is engaged by RBD of the SARS-CoV-2 spike glycoprotein and vice versa. Here, we used a dual strategy of molecular docking and surface plasmon resonance (SPR) screening of compound libraries to identify those that bind to human ACE2 or the SARS-CoV-2 spike protein receptor binding domain (RBD). Compounds that interfere with the SARS-CoV-2 spike protein receptor binding domain protein (RBD)-ACE2 receptor interaction may function as entry inhibitors. SARS-CoV-2 spike protein, like SARS-CoV-1, uses the angiotensin converting enzyme 2 (ACE2) as a cellular receptor to initiate infection. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a recently emerged virus that causes coronavirus infectious disease 2019 (COVID-19).
0 kommentar(er)
