The role of Efr3a in age-related hearing loss

Neuroscience. 2017 Jan 26:341:1-8. doi: 10.1016/j.neuroscience.2016.11.013. Epub 2016 Nov 17.

Abstract

Efr3a has been found to be involved in the functional maintenance and structural degeneration of sensory and motor nervous tissues. Our previous data have suggested that Efr3a may be associated with the initiation of the degeneration of spiral ganglion neurons (SGNs). In this study, we used Efr3a knockdown (Efr3a KD) and Efr3a overexpression (Efr3a OE) mice to determine the role of Efr3a in age-related hearing loss. Measurements of hearing thresholds showed that Efr3a had little or no influence on the hearing threshold at all frequencies in adult mice, whereas in an early stage of senescence, Efr3a reduction resulted in better hearing function, especially at 10 and 12months of age. No significant differences were observed in hair cell loss among the three groups until 14months. The number of surviving hair cells in the OE mice was lower than that in the KD mice. As indicated by the density of SGNs in the upper basal turn, the Efr3a OE mice displayed earlier and more severe degeneration than the KD mice. In addition, the p-Akt levels in the cochlear spiral ganglions were higher in adult Efr3a KD mice than in WT and OE mice, although there was no difference in Akt expression among the three groups. Our study suggests that down-regulation of Efr3a might improve hearing function and alleviate the degeneration of SGNs in an early stage of senescence, probably via enhancing the basal expression of activated Akt.

Keywords: Efr3a; age-related hearing loss; degeneration; hair cell; spiral ganglion neuron.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / metabolism*
  • Aging / pathology
  • Animals
  • Auditory Threshold / physiology
  • Cell Survival / physiology
  • Disease Models, Animal
  • Evoked Potentials, Auditory, Brain Stem / physiology
  • Hair Cells, Auditory / metabolism
  • Hair Cells, Auditory / pathology
  • Hearing Loss / metabolism*
  • Hearing Loss / pathology
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Nerve Degeneration / metabolism
  • Nerve Degeneration / pathology
  • Proto-Oncogene Proteins c-akt / metabolism
  • Spiral Ganglion / metabolism
  • Spiral Ganglion / pathology

Substances

  • EFR3A protein, mouse
  • Membrane Proteins
  • Proto-Oncogene Proteins c-akt