These drugs don’t target the coronavirus—they target us
Thousands of researchers around the world are investigating existing drugs as potential therapies for COVID-19, most of them looking at antivirals, such as remdesivir, developed to treat Ebola, or Kaletra, a combination drug against HIV. But Nevan Krogan, a molecular biologist at the University of California, San Francisco, sees another opportunity: “The virus can’t live by itself, right? It needs our genes and proteins in order to live and to replicate.” Camostat mesylate is one of several candidate drugs that block those interactions. They don’t target the virus, but us, the host.
To identify these drugs, scientists study the complicated molecular dance that happens between a virus and its host cells. For instance, from past work, researchers know in detail how other coronaviruses—those that cause severe acute respiratory syndrome and Middle East respiratory syndrome—infect a cell. First, a protein on the viral surface called the spike attaches to a receptor on the human cell called ACE2. Then, another human protein, TMPRSS2, cleaves the spike protein, allowing the virus to fuse with the cell and start to replicate inside it.
