Mammals Use RNA Interference Too

Like plants and invertebrates, mammalian cells also use RNA interference to protect themselves against viral infections.

AsianScientist (July 4, 2017) – In a study published in Immunity, researchers from China have found that small interferring RNAs (siRNAs) can be triggered and suppressed by human viruses. These findings provide evidence that RNA interference (RNAi), which is known to be an important antiviral mechanism in plants and invertebrates, also plays an antiviral role in mammals.

In eukaryotes such as fungi, plants and invertebrates, RNAi helps to fight viral infections by silencing the genes of invading viruses. Despite its important antiviral role in these organisms, it remains unclear if RNAi can function as an antiviral defense in mammals, particularly in differentiated somatic cells.

To find out, a team of researchers led by Dr. Zhou Xi at the State Key Laboratory of Virology, Wuhan Institute of Virology of the Chinese Academy of Science, and Dr. Qin Cheng-Feng from Beijing Institute of Microbiology and Epidemiology, studied what happened to mammalian cells when infected with HEV71, the enterovirus that causes hand, foot and mouth disease.

They found that the nonstructural protein 3A of HEV71 can suppress the production of RNAi in both mammalian cell cultures and mice. Furthermore, when the 3A protein was mutated, infection with HEV71 effectively triggered a RNAi response that was able to degrade viral RNA and limit the spread of the virus.

These findings highlight that RNAi can indeed function as an antiviral immunity in mammals. It also uncovers for the first time the detailed mechanism by which a human RNA virus evades antiviral RNAi in cell culture and animal models.

“This work defines RNAi as a novel antiviral immune pathway in mammals. Given the evolutionary conservation of RNAi in all eukaryotes, RNAi evolves from the simplest eukaryotic organisms to human beings, and keeps combating against viruses,” said Dr. Qiu Yang, the first author of the paper.

“Our study is a conceptual advance in antiviral immunity, and should inspire and attract more scientists to this field,” said Zhou.

The article can be found at: Qui et al. (2017) Human Virus-Derived Small RNAs Can Confer Antiviral Immunity in Mammals.


Source: Chinese Academy of Sciences; Photo: Shutterstock.
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