Bioinformatics Re-analysis of murine transcriptomic datasets identifies SASP and MAPK/NF-κB signaling pathways in noise-accelerated cochlear aging.

Noise exposure is an important contributor to age-related hearing loss (ARHL) or presbycusis; however, the underlying mechanism remains elusive. This study re-analyzed two Mus musculus cochlear transcriptomic datasets on acoustic trauma from the Gene Expression Omnibus (GEO) database to investigate mechanisms underlying noise-accelerated cochlear aging. We defined age-related differentially expressed genes (ARDEGs) as those genes that were both differentially expressed in response to noise exposure in cochleae and belonged to the aging-related genes (ARGs) set. This analytical step yielded 14 ARDEGs: Il6, Cxcl1, Ccl2, Ccl7, Icam1, Gdf15, Mmp10, Jun, Fos, Atf3, Gadd45b, Mbl1, Gem, and Atm. Functional enrichment analyses, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene set enrichment analysis (GSEA), revealed multiple biological processes and signaling pathways significantly associated with noise-accelerated cochlear aging. These pathways include the MAPK (notably the ERK cascade), NF-κB, JAK-STAT, and IL-18 signaling pathways. Using the ARDEGs, we constructed a classification model and identified signature genes associated with noise-induced cochlear injury within these two datasets. Exploratory analysis of the signature genes in a separate M. musculus dataset suggested their classification value and relevance in auditory tissue. Regulatory networks of the signature genes were constructed. Finally, immune cell infiltration was also analyzed. Our integrative analysis implicated inflammation, cell cycle arrest, aberrant extracellular matrix remodeling, and lipid peroxidation-associated atherosclerosis as potential mechanisms through which noise exposure accelerates cochlear aging.