U Alabama and Polish make claim that Covid-19 is more deadly than “common cold coronaviruses” because Covid-19 can “sponge up micro RNA that human cells need”
Human microRNAs, or miRNAs, are short, non-coding RNAs with about 22 bases. They act to regulate gene expression by their complementary pairing with specific messenger RNAs of the cell. That pairing silences the messenger RNA, preventing it from being translated into a protein. Thus, miRNAs are a fine-tuned controller of cell metabolism or the cell's response to stress and adverse challenges, like infection by a virus.
The miRNAs are only about 0.01 percent of total human cell and tissue RNA, while replicating viral RNA of a virus like the COVID-19 virus may reach 50 percent of the total cellular RNA. So, the UAB and Polish researchers say, if the COVID-19 virus has binding sites for specific miRNAs—and these sites are different from the binding sites for miRNAs found on coronaviruses that cause colds—the more pathogenic COVID-19 virus may selectively sponge up certain miRNAs to dysregulate the cell in ways that make it a dangerous human coronavirus.
The sponge idea is not novel. Viral RNA sponges have been shown capable of removing host miRNA by the Epstein-Barr virus, and sponge activity has also been shown for the herpes and hepatitis C viruses.
