The role of circulating miR-19b miRNA in predicting the outcome of COVID-19

Background. MicroRNAs are short (20–22 nucleotides) non-coding RNAs that can posttranscriptionally regulate gene expression and are considered a regulator of the innate immunity system. Previously, many papers were published on the prediction of the interaction of the single-stranded (+)RNA virus SARS-CoV-2 with human microRNAs, as well as on the profile of circulating microRNAs in patients with COVID-19 of varying severity. However, no works are analyzing the possible contribution of miRNAs circulating in blood plasma to the severity of COVID-19. The aim. To study the features of the blood plasma microRNA profile of patients with different severity of the new coronavirus infection COVID-19 and to evaluate the possibility of microRNA interaction with the SARS-CoV-2 genome. Materials and methods . The results of NGS sequencing of plasma miRNAs of 3 recovered and 8 deceased patients with a highly severe form of COVID-19 were studied. Differentially presented microRNAs were determined using bioinformatics methods, and their binding sites with the SARS-CoV-2 genome were predicted. Results. This study demonstrates that in patients who have recovered from a highly severe form of COVID-19, the level of hsa-miR-19b-3p in the blood plasma is significantly increased. This microRNA makes up about 1.5 % of all circulating microRNAs and can bind to SARS-CoV-2 regions encoding proteins that suppress intracellular immunity mechanisms (NSP3, NSP9). In addition, this miRNA can stimulate the functional activity and proliferation of cytotoxic T-lymphocytes, one of the critical components of acquired cellular immunity against SARS-CoV-2. Conclusion. The results of the study can be used in the development of antiviral drugs based on RNA interference, as well as in the development of predictive test systems to optimize the tactics of treating patients with COVID-19.