Insights from meta-analysis and experimental validation identify exosomal miR-146a-5p as a potential biomarker for sporadic amyotrophic lateral sclerosis.

MicroRNAs (miRNAs) have emerged as key regulators in the pathogenesis of amyotrophic lateral sclerosis (ALS). Despite growing evidence that miRNAs exhibit altered expression profiles in ALS, their utility as a biomarker remains limited. To address this, we conducted a meta-analysis using the Robust Rank Aggregation package, incorporating 20 differential miRNA profiling studies. Among these, miR-146a-5p emerged as the most dysregulated and significant miRNA in ALS (P = 0.0000142, P-adj = 0.0096), particularly in extracellular vesicle-derived studies. To evaluate its diagnostic accuracy, we validated miR-146a-5p expression in serum-derived exosomes and observed a significant increase in sporadic ALS (sALS) patients (n = 22) as compared to healthy controls (n = 18). Moreover, higher levels of miR-146a-5p were strongly associated with longer survival (≥ 5 years) (P = 0.0135), with a positive correlation between miR-146a-5p expression and survival duration (P = 0.0313) in sALS patients. Further, gene set enrichment analysis of miR-146a-5p target genes highlighted critical involvement of the Immune system and NF-kappa B signaling pathways in ALS pathophysiology. These findings highlight miR-146a-5p as a potential biomarker for ALS.