Since the development of the new crown epidemic, in addition to vaccines, some scientific teams around the world are still working on finding antiviral drugs. The new use of old drugs is one of the ideas for screening drug candidates. 
On the evening of April 7, local time, top international The academic journal “Nature” published online in the form of “Accelerated Article Preview” a study jointly completed by a team from King’s College London, Imperial College London, and the University of Trieste in Italy. It is “Drugs that inhibit TMEM16 proteins block SARS-CoV-2 Spike-induced syncytia”.
Research found that a drug commonly used to treat tapeworm infections, namely Niclosamide (Niclosamide),
div>May help prevent the formation of atypical fusion cells in the lungs of COVID-19 patients. The corresponding author of this study is Professor Mauro Giacca from King’s College London, UK.
The research team mentioned that COVID-19 is a disease with unique characteristics, including pulmonary thrombosis, frequent diarrhea, abnormal activation of inflammation, and rapid deterioration of lung function. Accompanied by alveolar edema. As of now, the pathological basis of these findings is unclear.
In this study, Giacca and colleagues studied the lungs of 41 patients who died of COVID-19 between March and May 2020. . They found that the pulmonary epithelial cells infected in the lungs of COVID-19 patients are abnormal and often merge together. Some of these fusion cells (also called syncytia) contain more than 20 different nuclei.
The study believes that the production of these syncytia is due to the activation of the SARS-CoV-2 spike protein (S protein) at the cell membrane level. This fusion process is affected by S Mediated by protein, S protein can trigger calcium oscillations and activate the protein named TMEM16F. 
drugs inhibit SARS-CoV-2 spike protein-induced syncytia.
Based on these observations, The research team screened more than 3000 clinically approved drugs to find out which molecules can inhibit the cell fusion induced by this spike protein.
The study screened out 83 It has carried out further experiments on 43 kinds of drugs that can prevent virus replication and cell damage. Among them, the antiparasitic drug niclosamide is one of the most effective molecules. Niclosamide was developed in the 1950s It was originally used as a molluscicide against Oncomelania snails, and was later approved for the treatment of tapeworm infections in the human body. It is known to have killing activity against a variety of viruses. 
drugs to SARS-CoV-2 The effect of replication and intracellular calcium oscillations.
According to the study, niclosamide can inhibit virus replication in experiments, weaken the calcium oscillations of cells expressing S protein, inhibit the activity of TMEM16F, and prevent S protein-induced synthesis The formation of cell bodies.
The research team pointed out that drugs known to inhibit other members of the TMEM16 protein family also performed well in these experiments, or could be aimed at the treatment of COVID-19 Start further research.
Link to the paper: https://nature.com/articles/s41586-021-03491-6