MicroRNAs (miRNAs)- A group of tiny RNAs that should attack the coronavirus when it tries to enter a host gets diminished with age and due to chronic ailments, according to a new report. This explains why older individuals and people with underlying health conditions are the most vulnerable to COVID-19.

What are MicroRNAs?

miRNAs are those tiny molecules that play a crucial role in one’s body in controlling gene expression and are also at the frontline during a virus invasion. They latch onto the genetic material of the virus- the RNA and cut through it. But with age and some chronic health conditions, the number of microRNAs diminish in number and reduces a person’s ability to respond to the viruses.

The deadly novel coronavirus is then able to hijack people’s cell machinery and then replicate, according to the report published in the journal Aging and Disease.

The Study:

The researchers analyzed the RNA sequence of two different coronaviruses- the SARS and the SARS-CoV-2. They looked at the sequence of the microRNAs that appeared to be fighting the virus and used computer simulation methods to figure out which of them would logically fit together like pieces of a puzzle. The findings revealed 848 microRNAs that target the SARS genome and 873 microRNAs that target the SARS-CoV-2 genome. They also identified some microRNAs that were unique to SARS and SARS-CoV-2.

Key Findings include:

  • MicroRNAs that were highly proficient at fighting the coronavirus changed much of the way the world functions
  • MicroRNAs that target the novel coronavirus were linked to more than 72 different biological processes including the production of molecules, immune response, etc.
  • Many of them become dysregulated and diminish in number with age and underlying health conditions such as diabetes or heart diseases
  • The decrease in the number of these tiny RNAs might explain the increased disease presentation and mortality rates in these individuals
  • In healthy, younger individuals, the microRNAs more aptly bind to the virus and prevent replication
  • The virus has a fairly uniform presence internationally

Culture studies and animal studies should be conducted to ensure that these findings are consistent with the computer analysis of human microRNAs in the study.

According to the Centers for Disease Control and Prevention (CDC), nearly 50% of COVID-19 patients who require hospitalization are aged 65 and above, and these individuals account for about 80% of coronavirus deaths. The increased case fatality rate in aged individuals is the most striking feature of COVID-19.

“My perspective is there is a key set of microRNAs that are important in triggering this abnormal response, in making older patients 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," EurekAlert quoted Dr. Carlos M. Isales, the study’s senior author and co-director of the MCG Center for Healthy Aging and chief of the MCG Division of Endocrinology, Diabetes, and Metabolism.

Patterns are emerging in patients presenting with severe COVID-19 symptoms
Patterns are emerging in patients presenting with severe COVID-19 symptoms AFP / LUCAS BARIOULET