Dexamethasone Regulates Cochlear Expression of Deafness-associated Proteins Myelin Protein Zero and Heat Shock Protein 70, as Revealed by iTRAQ Proteomics

Yukihide Maeda, Kunihiro Fukushima, Shin Kariya, Yorihisa Orita, Kazunori Nishizaki

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Abstract

Aim Using proteomics, we aimed to identify the proteins differentially regulated by dexamethasone in the mouse cochlea based on mass-spectrometry data. Background Glucocorticoid therapy is widely used for many forms of sensorineural hearing loss; however, the molecular mechanism of its action in the cochlea remains poorly understood. Methods Dexamethasone or control saline was intratympanically applied to the cochleae of mice. Twelve hours after application, proteins differentially regulated by dexamethasone in the cochlea were analyzed by isobaric Tag for Relative and Absolute Quantitation (iTRAQ)-mass spectrometry. Next, dexamethasone-dependent regulation of these proteins was verified in the cochleae of mice with noise-induced hearing loss (NIHL) and systemic administration of dexamethasone by western blotting. Immunolocalizations of these proteins were examined in cochleae with NIHL. Results A total of 247 proteins with a greater than 95% confidence interval of protein identification were found, and 11 differentially expressed proteins by dexamethasone were identified by the iTRAQ-mass spectrometry. One protein, myelin protein zero (Mpz), was upregulated (1.870 ± 0.201-fold change, p <0.01) at 6 hours post-systemic dexamethasone and noise exposure in a mouse model of NIHL. Heat shock protein 70 (Hsp70) was downregulated (0.511 ± 0.274-fold change, p <0.05) at 12 hours post-systemic dexamethasone. Immunohistochemistry confirmed Mpz localization to the efferent and afferent processes of the spiral neurons, whereas Hsp70 showed a more ubiquitous expression pattern in the cochlea. Conclusion Both Mpz and Hsp70 have been reported to be closely associated with sensorineural hearing loss in humans. Dexamethasone significantly modulated the expression levels of these proteins in the cochleae of mice.

Original languageEnglish
Pages (from-to)1255-1265
Number of pages11
JournalOtology and Neurotology
Volume36
Issue number7
DOIs
Publication statusPublished - Aug 27 2015

Fingerprint

Myelin P0 Protein
HSP70 Heat-Shock Proteins
Cochlea
Deafness
Proteomics
Dexamethasone
Noise-Induced Hearing Loss
Proteins
Mass Spectrometry
Sensorineural Hearing Loss
Glucocorticoids
Noise
Down-Regulation
Western Blotting
Immunohistochemistry
Confidence Intervals

Keywords

  • Charcot-Marie-Tooth neuropathy
  • Dexamethasone
  • Heat shock protein 70
  • Mouse cochlea
  • Myelin protein zero
  • Noise-induced hearing loss
  • Proteome
  • Sensorineural hearing loss

ASJC Scopus subject areas

  • Otorhinolaryngology
  • Clinical Neurology
  • Sensory Systems

Cite this

@article{57b4aaa7b8604e2c8ab7706e866ed73e,
title = "Dexamethasone Regulates Cochlear Expression of Deafness-associated Proteins Myelin Protein Zero and Heat Shock Protein 70, as Revealed by iTRAQ Proteomics",
abstract = "Aim Using proteomics, we aimed to identify the proteins differentially regulated by dexamethasone in the mouse cochlea based on mass-spectrometry data. Background Glucocorticoid therapy is widely used for many forms of sensorineural hearing loss; however, the molecular mechanism of its action in the cochlea remains poorly understood. Methods Dexamethasone or control saline was intratympanically applied to the cochleae of mice. Twelve hours after application, proteins differentially regulated by dexamethasone in the cochlea were analyzed by isobaric Tag for Relative and Absolute Quantitation (iTRAQ)-mass spectrometry. Next, dexamethasone-dependent regulation of these proteins was verified in the cochleae of mice with noise-induced hearing loss (NIHL) and systemic administration of dexamethasone by western blotting. Immunolocalizations of these proteins were examined in cochleae with NIHL. Results A total of 247 proteins with a greater than 95{\%} confidence interval of protein identification were found, and 11 differentially expressed proteins by dexamethasone were identified by the iTRAQ-mass spectrometry. One protein, myelin protein zero (Mpz), was upregulated (1.870 ± 0.201-fold change, p <0.01) at 6 hours post-systemic dexamethasone and noise exposure in a mouse model of NIHL. Heat shock protein 70 (Hsp70) was downregulated (0.511 ± 0.274-fold change, p <0.05) at 12 hours post-systemic dexamethasone. Immunohistochemistry confirmed Mpz localization to the efferent and afferent processes of the spiral neurons, whereas Hsp70 showed a more ubiquitous expression pattern in the cochlea. Conclusion Both Mpz and Hsp70 have been reported to be closely associated with sensorineural hearing loss in humans. Dexamethasone significantly modulated the expression levels of these proteins in the cochleae of mice.",
keywords = "Charcot-Marie-Tooth neuropathy, Dexamethasone, Heat shock protein 70, Mouse cochlea, Myelin protein zero, Noise-induced hearing loss, Proteome, Sensorineural hearing loss",
author = "Yukihide Maeda and Kunihiro Fukushima and Shin Kariya and Yorihisa Orita and Kazunori Nishizaki",
year = "2015",
month = "8",
day = "27",
doi = "10.1097/MAO.0000000000000748",
language = "English",
volume = "36",
pages = "1255--1265",
journal = "Otology and Neurotology",
issn = "1531-7129",
publisher = "Lippincott Williams and Wilkins",
number = "7",

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TY - JOUR

T1 - Dexamethasone Regulates Cochlear Expression of Deafness-associated Proteins Myelin Protein Zero and Heat Shock Protein 70, as Revealed by iTRAQ Proteomics

AU - Maeda, Yukihide

AU - Fukushima, Kunihiro

AU - Kariya, Shin

AU - Orita, Yorihisa

AU - Nishizaki, Kazunori

PY - 2015/8/27

Y1 - 2015/8/27

N2 - Aim Using proteomics, we aimed to identify the proteins differentially regulated by dexamethasone in the mouse cochlea based on mass-spectrometry data. Background Glucocorticoid therapy is widely used for many forms of sensorineural hearing loss; however, the molecular mechanism of its action in the cochlea remains poorly understood. Methods Dexamethasone or control saline was intratympanically applied to the cochleae of mice. Twelve hours after application, proteins differentially regulated by dexamethasone in the cochlea were analyzed by isobaric Tag for Relative and Absolute Quantitation (iTRAQ)-mass spectrometry. Next, dexamethasone-dependent regulation of these proteins was verified in the cochleae of mice with noise-induced hearing loss (NIHL) and systemic administration of dexamethasone by western blotting. Immunolocalizations of these proteins were examined in cochleae with NIHL. Results A total of 247 proteins with a greater than 95% confidence interval of protein identification were found, and 11 differentially expressed proteins by dexamethasone were identified by the iTRAQ-mass spectrometry. One protein, myelin protein zero (Mpz), was upregulated (1.870 ± 0.201-fold change, p <0.01) at 6 hours post-systemic dexamethasone and noise exposure in a mouse model of NIHL. Heat shock protein 70 (Hsp70) was downregulated (0.511 ± 0.274-fold change, p <0.05) at 12 hours post-systemic dexamethasone. Immunohistochemistry confirmed Mpz localization to the efferent and afferent processes of the spiral neurons, whereas Hsp70 showed a more ubiquitous expression pattern in the cochlea. Conclusion Both Mpz and Hsp70 have been reported to be closely associated with sensorineural hearing loss in humans. Dexamethasone significantly modulated the expression levels of these proteins in the cochleae of mice.

AB - Aim Using proteomics, we aimed to identify the proteins differentially regulated by dexamethasone in the mouse cochlea based on mass-spectrometry data. Background Glucocorticoid therapy is widely used for many forms of sensorineural hearing loss; however, the molecular mechanism of its action in the cochlea remains poorly understood. Methods Dexamethasone or control saline was intratympanically applied to the cochleae of mice. Twelve hours after application, proteins differentially regulated by dexamethasone in the cochlea were analyzed by isobaric Tag for Relative and Absolute Quantitation (iTRAQ)-mass spectrometry. Next, dexamethasone-dependent regulation of these proteins was verified in the cochleae of mice with noise-induced hearing loss (NIHL) and systemic administration of dexamethasone by western blotting. Immunolocalizations of these proteins were examined in cochleae with NIHL. Results A total of 247 proteins with a greater than 95% confidence interval of protein identification were found, and 11 differentially expressed proteins by dexamethasone were identified by the iTRAQ-mass spectrometry. One protein, myelin protein zero (Mpz), was upregulated (1.870 ± 0.201-fold change, p <0.01) at 6 hours post-systemic dexamethasone and noise exposure in a mouse model of NIHL. Heat shock protein 70 (Hsp70) was downregulated (0.511 ± 0.274-fold change, p <0.05) at 12 hours post-systemic dexamethasone. Immunohistochemistry confirmed Mpz localization to the efferent and afferent processes of the spiral neurons, whereas Hsp70 showed a more ubiquitous expression pattern in the cochlea. Conclusion Both Mpz and Hsp70 have been reported to be closely associated with sensorineural hearing loss in humans. Dexamethasone significantly modulated the expression levels of these proteins in the cochleae of mice.

KW - Charcot-Marie-Tooth neuropathy

KW - Dexamethasone

KW - Heat shock protein 70

KW - Mouse cochlea

KW - Myelin protein zero

KW - Noise-induced hearing loss

KW - Proteome

KW - Sensorineural hearing loss

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