In 2012, a new SARS-like coronavirus emerged in the Middle East, namely the Middle East respiratory syndrome coronavirus (MERS-CoV). It has caused outbreaks with high mortality. During infection of target cell, MERS-CoV S protein S1 subunit binds to the cellular receptor (DPP4), and its S2 subunit HR1 and HR2 regions intact with each other to form a stable six-helix bundle to mediate the fusion between virus and target cell membranes. Hence, blocking the process of six-helix bundle formation can effectively inhibit MERS-CoV entry into the target cells. This review focuses on the recent advance in the development of peptidic entry inhibitors targeting the MERS-CoV S2 subunit.
Antiviral Agents ; pharmacology ; Coronavirus Infections ; drug therapy ; Dipeptidyl Peptidase 4 ; metabolism ; Drug Design ; Humans ; Middle East Respiratory Syndrome Coronavirus ; drug effects ; physiology ; Peptides ; pharmacology ; Spike Glycoprotein, Coronavirus ; metabolism ; Virus Internalization ; drug effects

Amino Acid Sequence ; Coronavirus/drug effects* ; Coronavirus Infections/drug therapy* ; Drug Design ; Humans ; Protein Structure, Secondary ; Spike Glycoprotein, Coronavirus/metabolism* ; Viral Fusion Protein Inhibitors/pharmacology* ; Viral Fusion Proteins/metabolism*

Objective To explore the effects and mechanisms of a traditional Chinese medicine (TCM) prescription, "Fang-gan Decoction" (FGD), in protecting against SARS-CoV-2 spike protein-induced lung and intestinal injuries in vitro and in vivo.Methods Female BALB/c mice and three cell lines pretreated with FGD were stimulated with recombinant SARS-CoV-2 spike protein (spike protein). Hematoxylin-eosin (HE) staining and pathologic scoring of tissues, cell permeability and viability, and angiotensin-converting enzyme 2 (ACE2) expression in the lung and colon were detected. Enzyme-linked immunosorbent assay (ELISA) was performed to detect the levels of inflammatory factors in serum and cell supernatant. The expression of NF-κB p65, p-NF-κB p65, p-IκBα, p-Smad2/3, TGF-β1, Caspase3, and Bcl-2 was evaluated by Western blotting.Results FGD protected against the damage to the lung and colon caused by the spike protein in vivo and in vitro according to the pathologic score and cell permeability and viability (P<0.05). FGD up-regulated ACE2 expression, which was reduced by the spike protein in the lung and colon, significantly improved the deregulation of inflammatory markers caused by the spike protein, and regulated the activity of TGF-β/Smads and NF-κB signaling.Conclusion Traditional Chinese medicine has a protective effect on lung and intestinal tissue injury stimulated by the spike protein through possible regulatory functions of the NF-κB and TGF-β1/Smad pathways with tissue type specificity.
Mice ; Animals ; Female ; Humans ; NF-kappa B/metabolism* ; Spike Glycoprotein, Coronavirus/pharmacology* ; Transforming Growth Factor beta1/metabolism* ; Angiotensin-Converting Enzyme 2/pharmacology* ; COVID-19 ; SARS-CoV-2/metabolism* ; Lung ; Antineoplastic Agents ; Transforming Growth Factor beta/pharmacology* ; Epithelial Cells/metabolism* ; Colon

Middle East respiratory syndrome coronavirus (MERS-CoV) causes high fever, cough, acute respiratory tract infection and multiorgan dysfunction that may eventually lead to the death of the infected individuals. MERS-CoV is thought to be transmitted to humans through dromedary camels. The occurrence of the virus was first reported in the Middle East and it subsequently spread to several parts of the world. Since 2012, about 1368 infections, including ~487 deaths, have been reported worldwide. Notably, the recent human-to-human \'superspreading' of MERS-CoV in hospitals in South Korea has raised a major global health concern. The fatality rate in MERS-CoV infection is four times higher compared with that of the closely related severe acute respiratory syndrome coronavirus infection. Currently, no drug has been clinically approved to control MERS-CoV infection. In this study, we highlight the potential drug targets that can be used to develop anti-MERS-CoV therapeutics.
Animals ; Antiviral Agents/*pharmacology ; Cell Line ; Coronavirus Infections/drug therapy/*epidemiology/metabolism/*transmission ; Dipeptidyl Peptidase 4/metabolism ; Disease Outbreaks ; Drug Discovery ; Host-Pathogen Interactions/drug effects ; Humans ; Middle East Respiratory Syndrome Coronavirus/drug effects/*physiology ; Molecular Targeted Therapy ; Spike Glycoprotein, Coronavirus/metabolism

The coronavirus disease 2019(COVID-19) is raging in China and more than 20 other countries and regions since the middle of December 2019. Currently, there is no specific drug or vaccine besides symptomatic supportive therapy. Taking full advantage of the clinical experience of traditional Chinese medicine(TCM) in preventing and controlling major epidemics such as SARS, it is an important mission for TCM to propose effective formula with immediate response and solid evidence by using modern biomedical knowledge and techniques(molecular docking assisted TCM formulation for short). In view of the high homology between the gene sequences of the novel coronavirus and SARS virus, and the similarities between the two in terms of pathogenic mechanism and clinical manifestations, our team established a rapid screening and optimization model for the prevention and treatment of the novel coronavirus based on clinical experience and molecular docking technology. Firstly, the clinical team and the research team pre-developed and screened TCM formula by using "back-to-back" manner. Then, the formula was optimized and determined by comparing and analyzing the results of the two groups. The results showed that the research team screened out 46 active ingredients from candidate TCMs that could act on the novel coronavirus S-protein-binding site of human ACE2 protein, which were mainly attributed to 7 herbs such as Lonicerae Japonicae Flos and Mori Folium. The result was largely consistent with the formula raised by the clinical group, verifying and supporting its rationality. This provides evidence for the scientific and potential efficacy of the TCM prescription from the perspective of treatment target analysis, and also suggests that the TCM prescription has the potential to directly inhibit viral infection in addition to improving clinical symptoms or syndromes. Based on this, our team optimized and formed a new anti-coronavirus TCM prescription "Keguan Yihao", immediately providing the TCM prescription with certain clinical experience and objective evidence support for the prevention and treatment of new emergent infectious diseases in our hospital. The TCM prescription was combined with modern medicine symptomatic supportive treatment for clinical treatment, preliminary results showed better effect than symptomatic supportive therapy alone. This research has innovated the method mode in clinical practice and basic research integration of traditional Chinese medicine for the prevention and control of new emerging infectious diseases. It is of great significance to further improve the rapid response mechanism of TCM in face of major epidemics, and further improve the capability level of TCM to prevent and treat new emerging infectious diseases.
Angiotensin-Converting Enzyme 2 ; Angiotensin-Converting Enzyme Inhibitors/pharmacology* ; Betacoronavirus ; COVID-19 ; China ; Coronavirus Infections/drug therapy* ; Drugs, Chinese Herbal/pharmacology* ; Humans ; Medicine, Chinese Traditional ; Molecular Docking Simulation ; Pandemics ; Peptidyl-Dipeptidase A/chemistry* ; Pneumonia, Viral/drug therapy* ; SARS-CoV-2 ; Spike Glycoprotein, Coronavirus/chemistry* ; COVID-19 Drug Treatment