New research has identified the microRNAs that play a key role in combating SARS-CoV-2.
Scientists first discovered microRNAs in the mid-1990s. MicroRNAs are tiny fragments of RNA genetic sequence produced within the cells.
They play a role in fine-tuning how the body reads genetic code and turns it into protein. They usually switch off parts of the genetic code, but sometimes, they amplify it. They are also important in several conditions, ranging from cancer to cardiac disease, dementia, and viral infections.
When the body recognizes viral RNA within a cell, it produces a range of microRNAs that both enhance the body’s inflammatory response and act directly on the virus. The response is specific to each virus.
MicroRNAs decrease with age and due to underlying health conditions. This may explain why older adults and people with certain health concerns are more likely to die if they contract SARS-CoV-2.
The new research, which now appears in journal Aging and Disease, focuses on the interplay between microRNAs and the new coronavirus.
The findings may open the door to treatments that allow for the replacement of these microRNAs where necessary, hopefully reducing the risk of COVID-19 for the most vulnerable people.
The sudden and rapid spread of SARS-CoV-2 across the world has had scientists racing to understand precisely how the virus infects its hosts. Gaining a clear idea of how the virus functions is crucial if they are to produce effective treatments and, ultimately, a vaccine.
This is especially urgent given that certain risk factors increase the risk of some people dying after contracting the virus.
According to the Centers for Disease Control and Prevention (CDC), risk factors include being over the age of 65 and having conditions such as lung disease, heart conditions, obesity, or diabetes.
Understanding why these groups of people are at greater risk is important if scientists are to develop effective treatments.
Previous research has demonstrated the important role that microRNAs play in the body’s defense against viruses. MicroRNAs act in a number of ways to reduce replication of the virus within a host’s cell.
Given this fact, the authors of the new study wanted to identify which microRNAs did this work when responding to SARS-CoV-2. They also wanted to find out whether or not a person’s age or health status affected these microRNAs.
To do this, the researchers used computer modeling to identify precisely which microRNAs targeted SARS-CoV-2.
They analyzed the RNA sequence of different SARS-CoV-2 samples and the sequence of the microRNAs that appeared to be attacking the virus. This allowed the team to determine which microRNAs would best fit the virus RNA and thus effectively neutralize them.
They found that the microRNAs that would be effective in combating the virus were also crucial for numerous other processes in a person’s body, and that these microRNAs diminished as a person got older or if they had an underlying health condition.
Because of this, the researchers speculate that for older people and those with underlying health conditions, their bodies are not able to mount an effective defense against the virus — in part because of the lack of these specific microRNAs.
According to co-senior study author Dr. Carlos M. Isales, co-director of the MCG Center for Healthy Aging at Augusta University in Georgia, “[m]y perspective is there is a key set of microRNAs that are important in triggering this abnormal response, in making older [people] more susceptible.”
“We are looking at microRNAs in general dropping, but there is a specific subset that is key. The question is whether we can […] target those as a therapy.”
The researchers believe that a possible therapy could involve administering a mixture of microRNAs into a person’s nose, which could help restore their microRNAs to a level able to fight off the virus.
They have started the work of synthesizing this therapy. However, a drug useful for treatment in humans may be some way off, as work in this area is still in its infancy.
The researchers also note that — judging by the genetic samples of SARS-CoV-2, which they obtained from across the world and whose microRNA they examined — if they can indeed develop a treatment, it is likely to be effective at a wide scale.
To build on this research, the study authors want to explore which microRNAs would be most effective alongside other potential treatments for COVID-19.
Further, they need to test their findings in cultures and, ultimately, in a host organism to verify that their computer modeling works in a real-world setting.
Nonetheless, the new study sets the ground for this future research, which is urgently needed, given the significant lethality of the virus and the speed at which it can spread between hosts.
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