Integrative multi-dataset analysis identifies immune-inflammatory hub genes as diagnostic biomarkers and therapeutic targets for age-related hearing loss.

Age-related hearing loss (ARHL) is a common neurodegenerative disorder in the elderly, but its molecular mechanisms and diagnostic biomarkers remain unclear. Here, by using the GSE49543 dataset (n = 40, Affymetrix microarray) from the Gene Expression Omnibus (GEO) with limma, 17 ARHL-associated differentially expressed genes were identified, which were enriched in immune effector functions and the IL-17 signaling pathway. Weighted gene co-expression network analysis (WGCNA) further revealed that 168 genes were associated with hearing loss (module significance > 0.3). Intersecting DEGs with this module yielded 15 candidates, which were prioritized via protein-protein interaction (PPI) network (STRING) and CytoHubba algorithms to 7 core genes. Machine learning refined these to 5 hub genes: Fcgr3, Cd68, Lgals3, Laptm5, and Mpeg1, showing excellent diagnostic performance. Validation in five independent transcriptomic datasets (GSE49543, GSE6045, GSE153882, GSE154833, and GSE233798) confirmed their upregulation in ARHL samples, and experimental verification via quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC) further validated elevated mRNA (FCGR3, CD68, LGALS3, MPEG1) and protein (FCGR3, CD68, LGALS3) levels in aged mouse cochleae. Additionally, single-nucleus RNA sequencing (snRNA-seq) dataset GSE274279 was integrated to validate hub gene expression at single-cell resolution. These findings identify Fcgr3, Cd68, Lgals3, Laptm5, and Mpeg1 as immune-inflammatory hub genes with potential as diagnostic biomarkers and therapeutic targets for ARHL.