Circulating miRNA Biomarkers Linking NeuroCOVID and Cognitive Decline

Objective: SARS-CoV-2 infection can lead to neurological deficits in a significant number of patients. NeuroCOVID seems to be associated with an increased risk of developing a neurodegenerative disorder or could accelerate its progression. The aim is to investigate a potential link between NeuroCOVID and cognitive decline in blood samples from patients to understand this phenomenon and develop new therapeutic strategies. Methods: 15 healthy subjects, 8 affected by NeuroCOVID and 7 with Mild Cognitive Impairment were selected. RNA was extracted and reverse transcribed from the patients' plasma. The concentration of miRNAs was assessed by RT-qPCR. Results: In a previous study carried out by us, we identified three circulating miRNAs (miR-92a-3p, miR-320a and miR-320b) that regulate the MAPT gene differentially expressed in patients with frontotemporal dementia (FTD) compared to healthy controls and/or patients with Alzheimer's disease (AD). The analysis of these miRNAs in our populationshowed a significant increase in the expression of miR-320a and miR-320b in NeuroCOVID patients compared to controls. Additionally, miR-320b expression was increased in patients with MCI. No significant differences were observed for miR-92a-3p among the study groups. Conclusions: These findings indicate that the examined miRNAs, particularly miR-320a and miR-320b, are associated with both NeuroCOVID and MCI. Further investigation of these circulating biomarkers may help to identify shared molecular mechanisms underlying cognitive