MicroRNAs as Key Regulators in the Progression of Metabolic Dysfunction-Associated Steatotic Liver Disease: A Bioinformatics Analysis

<b>Background:</b> Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease, is a highly prevalent hepatic condition closely linked to metabolic syndrome (MetS). Epigenetic regulators such as microRNAs (miRNAs) have emerged as critical modulators of the molecular pathways underlying MASLD pathogenesis, offering new perspectives for non-invasive diagnosis and targeted therapy. This study aimed to identify and characterize target genes and pathways regulated by two key hepatic miRNAs, namely miR-122 and miR-29a, through a comprehensive in silico bioinformatics approach, to better understand their functional roles in MASLD and MetS. <b>Methods:</b> Target genes of miR-122 and miR-29a were predicted using three databases (TargetScan, DIANA-microT-CDS, and miRWalk), and those identified by at least two databases were selected for downstream analyses. Functional enrichment was performed using Gene Ontology and KEGG pathway analysis. Gene networks and biological process maps were constructed using Metascape, clusterProfiler and Cytoscape. <b>Results:</b> miR-122 was found to negatively regulate genes involved in lipid metabolism, insulin signaling, and inflammatory pathways, including <i>PPARGC1A</i>, <i>PPARA</i>, <i>LPL</i>, <i>TLR4</i>, and <i>HMGCR</i>, contributing to insulin resistance and liver dysfunction. By contrast, miR-29a demonstrated potential hepatoprotective effects by targeting <i>LEP</i>, <i>INSR</i>, <i>IL13</i>, and <i>IL18</i>, enhancing insulin sensitivity and reducing fibrogenic activity. Enrichment analysis revealed strong associations with biological processes, such as STAT phosphorylation, lipid homeostasis, and inflammatory signaling, as well as associations with cellular components, including lipoproteins and plasma membranes. miR-122 and miR-29a exhibit opposing regulatory functions in MASLD pathogenesis. Whereas miR-122 is associated with disease progression, miR-29a acts protectively. These miRNAs may serve as promising biomarkers and therapeutic targets in MASLD and related metabolic conditions. Further validation through experimental and clinical studies is warranted.