The rapid spread of the new coronavirus SARS-CoV-2 has resulted in a global pandemic of coronavirus disease (COVID-19) sadly resulting in millions of deaths and many more patients ill. The pandemic has shutdown economies all over the world.
While development of effective vaccines proceeded quickly and allowed the development of worldwide vaccination programs, there are still no effective therapies available to treat COVID patients with severe and life-threatening symptoms. Recent findings indicate the disease is hard to manage therapeutically and standard antivirals seem to be ineffective. Development of anti-viral drugs that inhibit or at least reduce viral spread and attenuate pathogenesis would be highly valuable in fighting the COVID-19 pandemic.
Currently, scientists worldwide are studying the infection process of SARS-CoV-2, searching for effective therapeutic solutions to prevent and cure the disease. One of most important targets in COVID-19 research is the Spike (S) Protein on the surface of the viral envelope that interacts with the ACE2 receptor on the surface of human cells. This protein mediates either fusion of the virus membrane with the host cell membrane (TMPRSS2 activated mediation) or endocytosis of the virus particle (Cathepsin-activated mediation) and its entry into the cell. The S Protein is important in both mechanism studies and the development of vaccines and therapeutics such as antibodies and chemical drug compounds.
By both routes, the S Protein plays a vital role in the process of SARS-CoV-2 infection. Recent research has found that both prior to and after attachment, the S Protein requires activation by cellular proteases (such as the serine protease TMPRSS2) to trigger viral entry into the target cell. A new approach to impede S Protein activation is being considered.
Another protease essential for priming the S Protein is Furin protease. It seems a furin-like cleavage site (FCS) in the S Protein, absent in other lineage B βCoVs (such as SARS-CoV), is responsible for the high infectivity and transmissibility of COVID-19. The pathogenicity of some coronaviruses strongly depends on the furin-like cleavage of the S Protein, which seems to worsen the symptoms of viral bronchitis, as well as increase viral pathogenicity.
A further host protease required for activation of the S Protein is Cathepsin L which also facilitates SARS-CoV-2 entry into target cells through an alternative route. This route enables virus uptake via endosomes by receptor-mediated endocytosis. The S Protein is then processed/activated by the lysosomal Cathepsin L in the late endosomes (endo-lysosomes) following endocytosis of the virus.
Inhibition of the Furin protease and Cathepsin L might therefore be an efficient way to attenuate the infection process and reduce the spread and severity of COVID-19. Specific Furin and Cathepsin L inhibitors which block proteolytic activation of the S Protein, and thus SARS-CoV-2 virus entry and replication, are potential antiviral agents to counteract SARS-CoV-2 infection and pathogenesis.
In addition to our assays for studying binding of SARS-CoV-2 to the ACE2 receptor and screening for respective inhibitors/drugs (see below), we offer the Furin Activity Assay Kit & Furin Inhibitor Screening Kit as well as Cathepsin L Activity Assay Kit & Cathepsin L Inhibitor Screening Kit as tools to develop new targeted therapeutics for Covid-19. In addition, a broad range of other Cathepsin Assays, Cathepsin Inhibitors as well as recombinant Cathepsins, Cathepsin antibodies & ELISAs also useful to study SARS-CoV infections (e.g. Cathepsin B) are available at PromoCell. We also supply a choice of Biochemicals with known inhibitory effects on SARS-CoVs as well as a range of high-quality Antibodies specifically directed against particular components of SARS-CoV and the ACE2 receptor.
Please note that our Spore-EX Disinfection Spray has been tested for its efficacy against coronavirus (validated according to EN14476).
See also our wide range of products for Respiratory Research.
Note: All products are for research use only and not for in vitro-diagnostic or therapeutic purposes.