Evaluation of Serum Levels of MicroRNA-200C and ACE2 Gene Expression in Severe and Mild Phases of Patients with COVID-19.

The role of microRNA (miR)200c-3p in regulating ACE2 gene expression in viral and bacterial respiratory diseases has been established. Since ACE2 reduces the acute inflammatory effects in lung diseases and acts as a coronavirus receptor to invade the lung cells, this study investigates the relationship between miR-200c-3p and ACE2 expression in COVID -19 patients. In this study, COVID-19 patients were divided into two groups: mild phase (PCR-positive and mild symptoms) and severe phase (PCR-positive with acute pulmonary symptoms and inflammation). Then, the subjects' demographic, clinical, and paraclinical characteristics were recorded using a prepared checklist. Total RNA was isolated from all samples according to the Trizol kit protocol to evaluate gene expression. Subsequently, the extracted product was analysed for miR-200c expression and ACE2 target gene expression by real-time PCR. The results of the checklist data showed that smoking, cough, and the factors ESR and HCT were statistically significant between the two groups of patients in the mild and acute phases. Also, the mean expression of the miR-200c gene in the mild and acute patients was 1.87±0.70 and 1.87±0.62, respectively, which was not statistically significant. Still, the mean expression of the ACE2 gene, which was 3.96±0.76 and 3.28±0.52 in the mild and acute disease groups, respectively, showed a significant difference between the two groups. This study showed that the expression levels of ACE2 were significantly reduced in people with severe inflammation compared to people with mild inflammation.