Therapeutic Options Against the New Coronavirus: Updated Clinical and Laboratory Evidences

Antisense oligonucleotide: A promising therapeutic option to beat COVID-19

The COVID-19 crisis and the development of the first approved mRNA vaccine have highlighted the power of RNA-based therapeutic strategies for the development of new medicines. Aside from RNA-vaccines, antisense oligonucleotides (ASOs) represent a new and very promising class of RNA-targeted therapy. Few drugs have already received approval from the Food and Drug Administration. Here, we underscored why and how ASOs hold the potential to change the therapeutic landscape to beat SARS-CoV-2 viral infections. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Small Molecule-RNA Interactions.

Development and Effects of Influenza Antiviral Drugs

Influenza virus is a highly contagious zoonotic respiratory disease that causes seasonal outbreaks each year and unpredictable pandemics occasionally with high morbidity and mortality rates, posing a great threat to public health worldwide. Besides the limited effect of vaccines, the problem is exacerbated by the lack of drugs with strong antiviral activity against all flu strains. Currently, there are two classes of antiviral drugs available that are chemosynthetic and approved against influenza A virus for prophylactic and therapeutic treatment, but the appearance of drug-resistant virus strains is a serious issue that strikes at the core of influenza control. There is therefore an urgent need to develop new antiviral drugs. Many reports have shown that the development of novel bioactive plant extracts and microbial extracts has significant advantages in influenza treatment. This paper comprehensively reviews the development and effects of chemosynthetic drugs, plant extracts, and microbial extracts with influenza antiviral activity, hoping to provide some references for novel antiviral drug design and promising alternative candidates for further anti-influenza drug development.

Potency, Safety, and Pharmacokinetic Profiles of Potential Inhibitors Targeting SARS-CoV-2 Main Protease

Effective, safe, and pharmacokinetically suitable drugs are urgently needed to curb the ongoing COVID-19 pandemic. The main protease or 3C-like protease (Mpro or 3CLpro) of SARS-CoV-2 is considered an important target to formulate potent drugs corresponding to its crucial role in virus replication and maturation in addition to its relatively conserved active site. Promising baseline data on the potency and safety of drugs targeting SARS-CoV-2 Mpro are currently available. However, preclinical and clinical data on the pharmacokinetic profiles of these drugs are very limited. This review discusses the potency, safety, and pharmacokinetic profiles of potential inhibitors of SARS-CoV-2 Mpro and forward directions on the development of future studies focusing on COVID-19 therapeutics.

Rationally Designed ACE2-Derived Peptides Inhibit SARS-CoV-2

Severe acute respiratory syndrome coronavirus (SARS-CoV)-2 is a novel and highly pathogenic coronavirus and is the causative agent of the coronavirus disease 2019 (COVID-19). The high morbidity and mortality associated with COVID-19 and the lack of an approved drug or vaccine for SARS-CoV-2 underscores the urgent need for developing effective antiviral therapies. Therapeutics that target essential viral proteins are effective at controlling virus replication and spread. Coronavirus Spike glycoproteins mediate viral entry and fusion with the host cell, and thus are essential for viral replication. To enter host cells, the Spike proteins of SARS-CoV-2 and related coronavirus, SARS-CoV, bind the host angiotensin-converting enzyme 2 (ACE2) receptor through their receptor binding domains (RBDs). Here, we rationally designed a panel of ACE2-derived peptides based on the RBD-ACE2 binding interfaces of SARS-CoV-2 and SARS-CoV. Using SARS-CoV-2 and SARS-CoV Spike-pseudotyped viruses, we found that a subset of peptides inhibits Spike-mediated infection with IC50 values in the low millimolar range. We identified two peptides that bound Spike RBD in affinity precipitation assays and inhibited infection with genuine SARS-CoV-2. Moreover, these peptides inhibited the replication of a common cold causing coronavirus, which also uses ACE2 as its entry receptor. Results from the infection experiments and modeling of the peptides with Spike RBD identified a 6-amino-acid (Glu37-Gln42) ACE2 motif that is important for SARS-CoV-2 inhibition. Our work demonstrates the feasibility of inhibiting SARS-CoV-2 with peptide-based inhibitors. These findings will allow for the successful development of engineered peptides and peptidomimetic-based compounds for the treatment of COVID-19.

COVID-19 and Neutrophils: The Relationship between Hyperinflammation and Neutrophil Extracellular Traps

Coronavirus disease 2019 (COVID-19) is a virus-induced respiratory disease that may progress to acute respiratory distress syndrome (ARDS) and is triggered by immunopathological mechanisms that cause excessive inflammation and leukocyte dysfunction. Neutrophils play a critical function in the clearance of bacteria with specific mechanisms to combat viruses. The aim of this review is to highlight the current advances in the pathways of neutrophilic inflammation against viral infection over the past ten years, focusing on the production of neutrophil extracellular traps (NETs) and its impact on severe lung diseases, such as COVID-19. We focused on studies regarding hyperinflammation, cytokine storms, neutrophil function, and viral infections. We discuss how the neutrophil's role could influence COVID-19 symptoms in the interaction between hyperinflammation (overproduction of NETs and cytokines) and the clearance function of neutrophils to eliminate the viral infection. We also propose a more in-depth investigation into the neutrophil response mechanism targeting NETosis in the different phases of COVID-19.