Low-dose rapamycin-induced autophagy in cochlear outer sulcus cells

Chika Saegusa, Makoto Hosoya, Takanori Nishiyama, Tsubasa Saeki, Chisato Fujimoto, Hideyuki Okano, Masato Fujioka, Kaoru Ogawa

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Objectives: Autophagy is an intracellular housekeeping process that degrades cytoplasmic organelles, damaged molecules, and abnormal proteins or pathogens and is essential for normal hearing. Recent studies revealed the essential roles of autophagy in hearing and balance. The aim of this study was to evaluate the activation state of rapamycin-induced autophagy in cochlear outer sulcus cells (OSCs). Methods: We used autophagy reporter transgenic mice expressing the green fluorescent protein-microtubule-associated protein light chain 3 (GFP-LC3) fusion protein and counted GFP-LC3 puncta in cochlear OSCs to evaluate the activation state of autophagy after oral administration of rapamycin. Results: We observed basal level GFP-LC3 expression and an increase in the number of GFP-LC3 puncta in cochlear OSCs by oral administration of rapamycin. This increase was detected when the daily rapamycin intake was as low as 0.025 mg/kg, and it was dose dependent. The increased number of puncta was more at the basal turn than the apical turn. Conclusion: Oral intake of low-dose rapamycin activates autophagy in cochlear OSCs. Level of evidence: NA.

Original languageEnglish
Pages (from-to)520-528
Number of pages9
JournalLaryngoscope investigative otolaryngology
Volume5
Issue number3
DOIs
Publication statusPublished - 2020 Jun 1

Keywords

  • autophagy
  • hearing loss
  • inner ear
  • outer sulcus cell
  • rapamycin

ASJC Scopus subject areas

  • Surgery
  • Otorhinolaryngology

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