Investigating the mechanisms of ageing and neuroinflammation in age-related hearing loss: A proteomic analysis

• Our aim was to identify protein evidence of age-related hearing loss (ARHL) influenced by aging and neuroinflammation. • Using proteomic research methods such as TMT, we successfully identified 7 proteins involved in ARHL due to aging and 2 proteins involved in ARHL due to neuroinflammation. • Through GO analysis, KEGG pathways, and GSEA analysis, we provided detailed descriptions of the pathways or mechanisms these proteins may be involved in, making significant contributions to the understanding of ARHL. Age-related hearing loss (ARHL) is a prevalent neurodegenerative condition commonly linked to aging and chronic inflammation. However, there is currently a lack of substantial proteomic evidence elucidating the underlying mechanisms within the brain. The study employed proteomic techniques to identify proteins as biomarkers for ARHL and to investigate and predict their underlying pathogenic mechanisms and potential intervention targets. In studying the impact of aging on ARHL, we found significant expression of 7 hearing-related proteins. including Mbp, Mag, Plp1, Orm1, Orm2, Tubb2b, Tuba3aa, and Tuba4a. These proteins were enriched in the ceramide-related pathway (CAMS), sphingolipid pathway, and microtubule transport pathway. Further investigations into the impact of chronic neuroinflammation, particularly reflecting the activation of microglial, revealed an improvement in hearing following the inhibition of microglial activation. Additionally, two proteins significantly associated with hearing were discovered to be expressed in the cochlear nucleus. Mag, Orm1, enriched in CAMs and sphingolipid pathways. In conclusion, we predict that aging may hinder the microtubule transport pathway, affect the CAMS and acidic glycoprotein pathways, influence the differential expression of proteins, thereby leading to the occurrence and development of ARHL. After the inhibition of microglia, key proteins of the CAMS and acidic glycoprotein pathways appeared among the differentially expressed proteins, which suggests that aging may induce ARHL by affecting myelin stripping in microglia, ultimately promoting the development of ARHL.