Role of microRNA-16-5p, microRNA-194, IP-10 and APRIL in inducing inflammation in SARS-CoV-2 infected patients with severe symptoms

The immune system is the main responsible candidate to induce pro-inflammatory conditions in the hospitalized SARS-CoV-2 infected patients. The roles played by humoral immunity-related factors in the pro-inflammatory conditions of the patients are yet to be clarified. It has been revealed that a proliferation-inducing ligand (APRIL), interferon (IFN)-γ-inducible protein 10 (IP-10), and microRNA-16-5p (miR-16-5p) play key roles in the induction of inflammation. Thus, this project was aimed to explore the expression levels of the molecules in the SARS-CoV-2 infected patients with severe symptoms. In addition, miR-194 can inhibit immune responses against viral infection. Another aim of this study was to evaluate expression of the molecule in the patients to explore the effects of the molecule during coronavirus disease 2019 (COVID-19). In this project, 60 severe SARS-CoV-2 infected patients who were in the peak of the disease and 60 healthy controls were enrolled to evaluate APRIL, IP-10, miR16-5p, and miR-194 expression levels. IP-10 expressions were evaluated using enzyme linked immunoassay (ELISA), while APRIL, miR-16-5p, and miR-194 were evaluated using Real-Time PCR technique. The results showed that APRIL, miR-16-5p, and miR-194 expression and serum levels of IP-10 significantly increased in the hospitalized SARS-CoV-2 infected patients in comparison to healthy controls. There was a positive correlation between miR-16-5p and miR-194 levels in the patients. Due to the fact that miR-16-5p significantly participates in the induction of inflammation, it, APRIL, and IP-10 may be the main parts of the excess inflammation in the hospitalized SARS-CoV-2 infected patients with severe symptoms. Up-regulation of miR-194 may be natural negative feedback to the pro-inflammatory conditions and may be associated with establishment of SARS-CoV-2 infection.