MicroRNA, which should attack the coronavirus, decreases with age. This explains why older people and patients with chronic illnesses are more likely to tolerate COVID-19 harder and die, according to a study by scientists from the Center for Healthy Aging at Georgia College of Medicine. The work was published in the journal Aging and Disease.
MicroRNAs are short non-coding RNAs with a length of about 22 nucleotides. They play an important role in the human body: when a virus enters, they fix and cut its RNA, preventing it from integrating into the genome of healthy cells.
In a new study, scientists found that with age, the number of microRNAs decreases – this directly affects the body’s ability to fight viruses, greatly reducing its protection.
In their work, scientists investigated two viruses of the SARS family – the causative agent of SARS in 2002 and the causative agent COVID-19, which caused the current pandemic. They then examined the miRNA sequence, which appears to attack the virus.
Computer modeling based on the data obtained allowed scientists to detect 848 miRNAs that target the SARS genome, and 873 miRNAs that target the SARS-CoV-2 genome.
Sequences fighting SARS-CoV-2 are influenced by 72 biological processes — from the production of molecules to the immune response — many of which are uncontrolled and actually stop with age. In addition, they are affected by chronic diseases.
According to the authors of the study, a decrease in the number of microRNAs due to aging or chronic diseases can explain the more severe course of COVID-19 in such patients.