Prioritization of Candidate miRNA Regulators Targeting Fibrotic-Immune Remodeling in Ligamentum Flavum Hypertrophy: An Integrated mRNA-miRNA Transcriptomic Study.

Background: Ligamentum flavum hypertrophy (LFH) is a major structural contributor to lumbar spinal stenosis and is characterized by extracellular matrix (ECM) remodeling with an increasingly recognized immune-associated component. However, the regulatory architecture linking disease-associated microRNA (miRNA) dysregulation to LFH transcriptomic remodeling remains incompletely defined. Methods: Public Gene Expression Omnibus datasets were analyzed using an integrated mRNA-miRNA transcriptomic framework. Single-cell RNA sequencing (GSE294458) was used to characterize the cellular landscape of hypertrophic and non-hypertrophic ligamentum flavum, whereas bulk transcriptomic analysis (GSE113212) identified LFH-associated differentially expressed genes. Differentially expressed miRNAs from an ossified ligamentum flavum dataset (GSE106256) were integrated with LFH-associated mRNA profiles through inverse miRNA-mRNA regulatory filtering. Functional enrichment, STRING protein-protein interaction (PPI) analysis, cytoHubba hub gene prioritization, LASSO regression, ROC analysis, remodeling-signature scoring, DGIdb, ChEA, and database-supported miRNA-target annotation were subsequently performed. Results: Single-cell analysis supported fibroblast-, myofibroblast-, and ECM-associated remodeling in hypertrophic ligamentum flavum. Bulk analysis identified nine significant differentially expressed genes, and integration with 33 dysregulated miRNAs generated 651 inverse-regulated core genes. Enrichment analyses highlighted ECM organization, proteoglycan/glycosaminoglycan (GAG) biology, immune cell differentiation, antigen presentation, and NF-κB/Wnt-related pathways. The STRING network included 650 nodes and 547 edges, with significant PPI enrichment (p = 2.04 × 10-14). LASSO prioritized PABPC1 and RPL4 as exploratory candidate hub features showing apparent discovery-cohort discrimination (AUC = 1.00); supplementary uncertainty, internal-stability, and separation-aware sensitivity analyses supported interpretation of this finding as a discovery-cohort signal rather than as independent diagnostic validation. Remodeling-signature analyses showed increased ECM fibrosis and proteoglycan/GAG scores, with inverse associations involving PABPC1 and RPL4. Multi-layer prioritization identified hsa-miR-708-5p as the leading candidate, followed by hsa-miR-23b-3p, hsa-miR-191-5p, hsa-miR-181a-5p, and hsa-miR-653-5p. Conclusions: This integrated mRNA-miRNA transcriptomic analysis delineated a coordinated fibrotic-immune remodeling landscape in LFH and prioritized experimentally testable miRNA candidates linked to network-central regulatory pathways.