MicroRNA sequencing of peripheral blood mononuclear cells reveals significant expression changes in women with Long COVID.

Long COVID is a clinical condition marked by persistent symptoms like fatigue and brain fog, estimated to have affected many of post-SARS-CoV-2/COVID-19 infection patients. This study, conducted with adult female Long COVID patients from Pedro Ernesto University Hospital (HUPE) in Rio de Janeiro, investigated the role of microRNAs (miRNAs), key post-transcriptional gene expression regulators, in this new condition. Next-generation sequencing (NGS) and bioinformatics analysis of miRNAs extracted from Peripheral Blood Mononuclear Cells (PBMCs) revealed differential expression of 37 miRNAs (10 upregulated, 27 downregulated). Notably, 28 of these miRNAs have been previously linked to inflammation or COVID-19, a significant finding given Long COVID's association with a persistent inflammatory state and potential for serious adverse events. Validation by qPCR confirmed hsa-miR-1307-3p, hsa-miR-26a-5p, and miR-186-5p as potential Long COVID biomarkers. The continuous overexpression of hsa-miR-1307-3p, which bound to the initial SARS-CoV-2 variants, may have contributed to increased inflammatory factors. Understanding how miRNAs modulate the inflammatory cascade could be crucial in mitigating the global health impact of future pandemics.