ERBB2 is a Key Mediator in Hearing Restoration in Noise-Deafened Young Adult Mice

Abstract

Noise induced hearing loss (NIHL) affects over ten million adults in the United States, and there is no biological treatment to restore endogenous function after damage. We hypothesized that activation of signaling from ERBB2 receptors in cochlear supporting cells could mitigate NIHL damage. We used the Tet-On genetic expression system to drive a constitutively active variant of ERBB2 (CA-ERBB2) in cochlear supporting cells three days after permanent noise damage in young adult mice. Hearing thresholds were assessed with auditory brainstem response tests prior to noise damage, and hearing recovery was assessed over a three month period. We evaluated supporting cell proliferation, inner and outer hair cell (IHC and OHC) survival, synaptic preservation, and IHC cytoskeletal alterations with histological techniques. Mice harboring CA-ERBB2 capability had similar hearing thresholds to control littermates prior to and immediately after noise exposure, and incurred similar levels of permanent hearing loss. Two and three months after noise exposure, CA-ERBB2+ mice demonstrated a partial but significant reversal of NIHL threshold shifts at the lowest frequency tested, out of five frequencies (n=19 total mice, p=0.0015, ANOVA). We also observed improved IHC and OHC survival (n=7 total cochleae, p=5 x 10 -5 , Kruskal-Wallis rank sum test). There was no evidence for sustained supporting cell proliferation. Some mortality was associated with doxycycline and furosemide treatments to induce the Tet-ON system. These data suggest that ERBB2 signaling in supporting cells promotes HC repair and some functional recovery. Funded by NIH R01 DC014261, and grants from the Schmitt Foundation and UR Ventures.

Single cell RNA sequencing analysis of mouse cochlear supporting cell transcriptomes with activated ERBB2 receptor, a candidate mediator of cochlear regeneration mechanisms

“…Three weeks old mice were genotyped and weaned, and tamoxifen injections (75 mg/kg) were performed at P21, P22 and P23. At P28 their hearing was tested by auditory brainstem response (ABR) and distortion product acoustic emissions (DPOAE) 21 . The mice were then divided into DOX exposed and control conditions.…”

“…Consistent with this interpretation, SOX2 protein was broadly down-regulated in the apical turn harboring sparse CA-ERBB2+ cells 20 . In a companion paper, we use the same transgenic mouse model to demonstrate that activation of the ERBB2-mediated signaling in supporting cells in young adult mice after traumatic noise damage correlates with partial low-frequency auditory recovery 21 .…”

Single cell RNA sequencing analysis of mouse cochlear supporting cell transcriptomes with activated ERBB2 receptor, a candidate mediator of hearing restoration mechanisms.

“…Tamoxifen injections (75 mg/kg) were performed at P21, P22 and P23. At P28 their hearing was tested by auditory brainstem response (ABR) and distortion product acoustic emissions (DPOAE) 75 . The mice were then divided into DOX exposed and control conditions.…”

“…The mice were then divided into DOX exposed and control conditions. Mice experienced a noise exposure of 110 dB of 8-16 kHz octave band noise for 2 hours, as described previously 75 . The next day (1 DPN), mice received hearing tests to con rm severe noise-induced hearing loss evident by threshold shift for at least 25 dB across ve frequencies (8, 12, 16, 24 and 32 kHz).…”

Perspectives on Human Hearing Loss, Cochlear Regeneration, and the Potential for Hearing Restoration Therapies

“…Lastly, restoring hearing after noise damage may require additional approaches beyond assessing pathways that promote HC differentiation. Figure 3 shows representative data for a four-month old genetic control mouse from a noise damage experiment (see [ 135 ] for methods and statistical analysis). The mouse was an F1 hybrid of CBA/CaJ mated to C57BL6/J, a cross that exhibits good hearing up to a year of age and youthful sensitivity to noise [ 136 ].…”