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Deng X, Hu Z. Hearing Recovery Induced by DNA Demethylation in a Chemically Deafened Adult Mouse Model. Front Cell Neurosci 2022; 16:792089. [PMID: 35250483 PMCID: PMC8891629 DOI: 10.3389/fncel.2022.792089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 01/04/2022] [Indexed: 11/13/2022] Open
Abstract
Functional hair cell regeneration in the adult mammalian inner ear remains challenging. This study aimed to study the function of new hair cells induced by a DNA demethylating agent 5-azacytidine. Adult mice were deafened chemically, followed by injection of 5-azacytidine or vehicle into the inner ear. Functionality of regenerated hair cells was evaluated by expression of hair cell proteins, auditory brainstem response (ABR), and distortion-product otoacoustic emission (DPOAE) tests for 6 weeks. In the vehicle-treated group, no cells expressed the hair cell-specific protein myosin VIIa in the cochlea, whereas numerous myosin VIIa-expressing cells were found in the 5-azacytidine-treated cochlea, suggesting the regeneration of auditory hair cells. Moreover, regenerated hair cells were co-labeled with functional proteins espin and prestin. Expression of ribbon synapse proteins suggested synapse formation between new hair cells and neurons. In hearing tests, progressive improvements in ABR [5–30 dB sound pressure level (SPL)] and DPOAE (5–20 dB) thresholds were observed in 5-azacytidine-treated mice. In vehicle-treated mice, there were <5 dB threshold changes in hearing tests. This study demonstrated the ability of 5-azacytidine to promote the functional regeneration of auditory hair cells in a mature mouse model via DNA demethylation, which may provide insights into hearing regeneration using an epigenetic approach.
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Affiliation(s)
- Xin Deng
- Department of Otolaryngology-Head and Neck Surgery (HNS), Wayne State University School of Medicine, Detroit, MI, United States
| | - Zhengqing Hu
- Department of Otolaryngology-Head and Neck Surgery (HNS), Wayne State University School of Medicine, Detroit, MI, United States
- John D. Dingell VA Medical Center, Detroit, MI, United States
- *Correspondence: Zhengqing Hu,
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