Researchers identify protein that could block bioterror pathogens

A team of researchers from UCLA recently identified a protein with broad virus-fighting properties that could potentially protect against Ebola virus and other pathogens designated as priority pathogens for national biosecurity purposes.

In the study, which was published in January in the journal Immunity, the researchers described the novel antiviral properties of cholesterol-25-hydroxylase, an enzyme that converts cholesterol to an oxysterol that can block a virus from getting into cells. The CH25H enzyme is activated by interferon, an essential antiviral cell-signaling protein in the body.

"Antiviral genes have been hard to apply for therapeutic purposes because it is difficult to express genes in cells," Su-Yang Liu, the lead author of the study, said. "CH25H, however, produces a natural, soluble oxysterol that can be synthesized and administered. Also, our initial studies showing that 25HC can inhibit HIV growth in vivo should prompt further study into membrane-modifying cholesterols that inhibit viruses."

Liu and his team found that 25HC dramatically inhibited HIV in cell cultures and that the enzyme significantly reduced the HIV load of mice implanted with human tissues within seven days. The enzyme also reversed T-cell depletion caused by HIV.

The study also determined that the enzyme inhibited the growth of other deadly viruses like Nipah, Ebola and the Rift Valley Fever virus.

The research represents the first description of an interferon-induced antiviral oxysterol through the activation of the CH25H enzyme.

Liu said that CH25H is difficult to deliver in large doses and the antiviral effect against Nipah, Ebola and other highly pathogenic viruses has not been tested in vivo. Future studies may compare the enzyme's antiviral effect against other HIV antivirals.