MiR-29a-deficiency causes thickening of the basilar membrane and age-related hearing loss by upregulating collagen IV and laminin

Peng Ma; Shuli Wang; Ruishuang Geng; Yongfeng Gong; Mulan Li; Daoli Xie; Yaning Dong; Tihua Zheng; Bo Li; Tong Zhao; Qingyin Zheng

doi:10.3389/fncel.2023.1191740

MiR-29a-deficiency causes thickening of the basilar membrane and age-related hearing loss by upregulating collagen IV and laminin

Front Cell Neurosci. 2023 May 18:17:1191740. doi: 10.3389/fncel.2023.1191740. eCollection 2023.

Authors

Peng Ma^#^{1

2}, Shuli Wang^#³, Ruishuang Geng³, Yongfeng Gong², Mulan Li³, Daoli Xie³, Yaning Dong³, Tihua Zheng³, Bo Li³, Tong Zhao³, Qingyin Zheng^{1

4}

Affiliations

¹ School of Basic Medicine, Qingdao University, Qingdao, China.
² School of Basic Medicine, Binzhou Medical University, Yantai, China.
³ Department of Hearing and Speech Rehabilitation, School of Special Education, Binzhou Medical University, Yantai, China.
⁴ Department of Otolaryngology, Case Western Reserve University, Cleveland, OH, United States.

^# Contributed equally.

Abstract

Age-related hearing loss (ARHL) is the most common sensory degenerative disease and can significantly impact the quality of life in elderly people. A previous study using GeneChip miRNA microarray assays showed that the expression of miR-29a changes with age, however, its role in hearing loss is still unclear. In this study, we characterized the cochlear phenotype of miR-29a knockout (miR-29a^-/-) mice and found that miR-29a-deficient mice had a rapid progressive elevation of the hearing threshold from 2 to 5 months of age compared with littermate controls as measured by the auditory brainstem response. Stereocilia degeneration, hair cell loss and abnormal stria vascularis (SV) were observed in miR-29a^-/- mice at 4 months of age. Transcriptome sequencing results showed elevated extracellular matrix (ECM) gene expression in miR-29a^-/- mice. Both Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that the key differences were closely related to ECM. Further examination with a transmission electron microscope showed thickening of the basilar membrane in the cochlea of miR-29a^-/- mice. Five Col4a genes (Col4a1-a5) and two laminin genes (Lamb2 and Lamc1) were validated as miR-29a direct targets by dual luciferase assays and miR-29a inhibition assays with a miR-29a inhibitor. Consistent with the target gene validation results, the expression of these genes was significantly increased in the cochlea of miR-29a^-/- mice, as shown by RT-PCR and Western blot. These findings suggest that miR-29a plays an important role in maintaining cochlear structure and function by regulating the expression of collagen and laminin and that the disturbance of its expression could be a cause of progressive hearing loss.

Keywords: basilar membrane; collagen IV; hair cells; hearing loss; miR-29a.

Grants and funding

This work was supported by grants from the Shandong Provincial Natural Science Foundation of China (ZR2020KH025), the National Natural Science Foundation of China (81530030 and 81873697), the National Institutes of Health (R01DC015111 and R21DC005846), and Binzhou Medical University start-up fund to RG.