Circulating extracellular vesicle-miRNAs as epigenetic mediators of metabolic, inflammatory, and neurological pathways in pediatric obesity.

Pediatric obesity represents a significant global health concern, associated with increased risk of early-onset metabolic disorders, chronic inflammation, and neurodevelopmental complications. Understanding the epigenetic mechanisms underlying obesity-induced metabolic and inflammatory dysregulation is essential for effective prevention and treatment. This pilot study provides the first comprehensive analysis of circulating extracellular vesicle (EV)-derived microRNAs (miRNAs) in pediatric obese individuals. Using age-and sex-matched pediatric obese (pOB) and healthy-weight controls (pNW), we identified distinct EV-miRNA signatures associated with pediatric obesity. Plasma EVs were isolated via tangential flow filtration and characterized using microfluidic resistive pulse sensing, transmission electron microscopy, and immunoblotting for canonical EV markers (CD81, CD63) and non-EV markers (calnexin). Differential miRNA profiling revealed significant obesity-driven epigenetic alterations, including known miRNAs involved in adipogenesis (miR-29a-3p, miR-643), lipid metabolism (miR-339-5p, miR-328-3p), inflammatory responses (miR-142-5p, miR-1249-3p), insulin signaling (let-7a-5p), and novel miRNAs (miR-1268a, miR-1268b, miR-3173-5p). Functional enrichment analyses using Kyoto Encyclopedia of Genes and Genomes and Gene Ontology highlighted significant regulation of pathways central to lipid metabolism, insulin resistance, mitochondrial function, immune activation, and neuronal signaling. Notable pathways, including PI3K-Akt signaling, MAPK signaling, calcium signaling, and axon guidance, were significantly enriched, emphasizing the systemic and central nervous system implications of the brain-fat axis in obesity. These findings underscore the potential of circulating EV-miRNAs as minimally invasive epigenetic biomarkers and epigenetic therapeutic targets for pediatric obesity. Larger studies are needed to validate the theranostic potential of EV-miRNAs in pediatric obesity.