Asian herb holds promise in fight against Ebola

A molecule derived from an Asian herb may protect against Ebola by switching off the channels which the deadly virus uses to enter and infect cells, a new study suggests.
Researchers said that the small molecule called Tetrandrine has shown to be potent in inhibiting infection of human white blood cells in vitro or petri dish experiments and prevented Ebola virus disease in mice.
Scientists at Texas Biomedical Research Institute have been working on stopping the virus before it has a chance to enter or interact with cellular factors, as that is a critical first step to combating infection.
Ebola virus begins its entry into a cell by first binding to several types of cell surface proteins.

Then the virus is taken into the cell and follows an endosomal route, or membrane-bound route that transports the virus to various cell compartments.
From previous studies, scientists knew that calcium signalling in cells, which allow cells to transmit electrical charges to one another, controls many of the processes in the cell and was important for Ebola virus infection.

"With this research, we discovered that two pore channels (TPCs) are the key calcium sensor involved in Ebola virus infection. These TPCs essentially needed to be turned on in order for the virus to function properly," said Robert Davey, from the Department of Immunology and Virology.

Two pore channels are unusual calcium channels found in endosomes that control the way endosomes move through cells and the environment of the cells.
Working with a group in Munich, Germany and Southwest Research Institute, the team tested several small molecules to see which was most effective at turning the sensors off, thus prohibiting Ebola virus from moving any further through the cell.
The team found Tetrandrine protected mice from disease without obvious side effects and was the best candidate for further animal testing, because it was the most potent compound tested, gave little evidence of cytotoxicity and required a smaller dose to be effective and tolerated.

"When we tested in mice, the drugs stopped virus replication and saved most of them from disease," Davey said.
Essentially, this drug shows an ability to stop the virus before it has a chance to interact with cellular factors, thus stopping the virus from continuing its infection process.
"We are cautiously optimistic. The next step in the process is to test both safety and effectiveness of the interaction of the drug with Ebola virus in non-human primates," Davey added.
The research was published in the journal Science.