Osteopontin is not critical for otoconia formation or balance function

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Unlike the structural and mechanical role of bone crystals, the inertial mass of otoconia crystals provides a shearing force to stimulate the mechanoreceptors of the utricle and saccule (the gravity receptor organ) under the stimuli of linear motion. It is not clear whether otoconia, composed primarily of CaCO3 and glycoproteins, go through similar calcification processes as bone. We have recently shown that otoconin-90 (Oc90) regulates the growth of otoconia crystals as osteopontin does bone crystals. Here, we analyzed the role of this non-collagenous bone matrix protein, osteopontin, in otoconia formation and balance function utilizing its knockout mice, whose inner ear phenotype has not been examined. Despite the presence of the protein in wild-type otoconia and vestibular hair cells, morphological, ultrastructural, and protein and calcium composition analyses of osteopontin null otoconia show that the protein is not needed for crystal formation, and no evidence of compensatory protein deposition is found. Employment of a wide spectrum of balance behavioral tests demonstrates that the protein is not critical for balance function either, which is confirmed by the normal function of the gravity receptor organ directly measured with linear vestibular-evoked potentials (VsEPs). When compared with findings on other otoconins, the data manifest a hierarchy of importance of proteins in crystallization and indicate mechanistic similarities and differences between bone and otoconia calcification.

Original languageEnglish (US)
Pages (from-to)191-201
Number of pages11
JournalJARO - Journal of the Association for Research in Otolaryngology
Volume9
Issue number2
DOIs
StatePublished - Jun 1 2008

Fingerprint

Otolithic Membrane
Osteopontin
Proteins
Bone and Bones
Gravitation
Crystallization
Vestibular Hair Cells
Saccule and Utricle
Mechanoreceptors
Bone Matrix
Inner Ear
Evoked Potentials
Knockout Mice
Glycoproteins
Calcium
Phenotype

Keywords

  • Balance behaviors
  • Bone
  • Calcification
  • Vestibular-evoked potentials

ASJC Scopus subject areas

  • Otorhinolaryngology
  • Sensory Systems

Cite this

@article{7afbcf0c9e9a44eeb669ddcfc2a2af70,
title = "Osteopontin is not critical for otoconia formation or balance function",
abstract = "Unlike the structural and mechanical role of bone crystals, the inertial mass of otoconia crystals provides a shearing force to stimulate the mechanoreceptors of the utricle and saccule (the gravity receptor organ) under the stimuli of linear motion. It is not clear whether otoconia, composed primarily of CaCO3 and glycoproteins, go through similar calcification processes as bone. We have recently shown that otoconin-90 (Oc90) regulates the growth of otoconia crystals as osteopontin does bone crystals. Here, we analyzed the role of this non-collagenous bone matrix protein, osteopontin, in otoconia formation and balance function utilizing its knockout mice, whose inner ear phenotype has not been examined. Despite the presence of the protein in wild-type otoconia and vestibular hair cells, morphological, ultrastructural, and protein and calcium composition analyses of osteopontin null otoconia show that the protein is not needed for crystal formation, and no evidence of compensatory protein deposition is found. Employment of a wide spectrum of balance behavioral tests demonstrates that the protein is not critical for balance function either, which is confirmed by the normal function of the gravity receptor organ directly measured with linear vestibular-evoked potentials (VsEPs). When compared with findings on other otoconins, the data manifest a hierarchy of importance of proteins in crystallization and indicate mechanistic similarities and differences between bone and otoconia calcification.",
keywords = "Balance behaviors, Bone, Calcification, Vestibular-evoked potentials",
author = "Xing Zhao and Jones, {Sherri M} and Thoreson, {Wallace B} and Lundberg, {Yunxia W}",
year = "2008",
month = "6",
day = "1",
doi = "10.1007/s10162-008-0117-z",
language = "English (US)",
volume = "9",
pages = "191--201",
journal = "JARO - Journal of the Association for Research in Otolaryngology",
issn = "1525-3961",
publisher = "Springer New York",
number = "2",

}

TY - JOUR

T1 - Osteopontin is not critical for otoconia formation or balance function

AU - Zhao, Xing

AU - Jones, Sherri M

AU - Thoreson, Wallace B

AU - Lundberg, Yunxia W

PY - 2008/6/1

Y1 - 2008/6/1

N2 - Unlike the structural and mechanical role of bone crystals, the inertial mass of otoconia crystals provides a shearing force to stimulate the mechanoreceptors of the utricle and saccule (the gravity receptor organ) under the stimuli of linear motion. It is not clear whether otoconia, composed primarily of CaCO3 and glycoproteins, go through similar calcification processes as bone. We have recently shown that otoconin-90 (Oc90) regulates the growth of otoconia crystals as osteopontin does bone crystals. Here, we analyzed the role of this non-collagenous bone matrix protein, osteopontin, in otoconia formation and balance function utilizing its knockout mice, whose inner ear phenotype has not been examined. Despite the presence of the protein in wild-type otoconia and vestibular hair cells, morphological, ultrastructural, and protein and calcium composition analyses of osteopontin null otoconia show that the protein is not needed for crystal formation, and no evidence of compensatory protein deposition is found. Employment of a wide spectrum of balance behavioral tests demonstrates that the protein is not critical for balance function either, which is confirmed by the normal function of the gravity receptor organ directly measured with linear vestibular-evoked potentials (VsEPs). When compared with findings on other otoconins, the data manifest a hierarchy of importance of proteins in crystallization and indicate mechanistic similarities and differences between bone and otoconia calcification.

AB - Unlike the structural and mechanical role of bone crystals, the inertial mass of otoconia crystals provides a shearing force to stimulate the mechanoreceptors of the utricle and saccule (the gravity receptor organ) under the stimuli of linear motion. It is not clear whether otoconia, composed primarily of CaCO3 and glycoproteins, go through similar calcification processes as bone. We have recently shown that otoconin-90 (Oc90) regulates the growth of otoconia crystals as osteopontin does bone crystals. Here, we analyzed the role of this non-collagenous bone matrix protein, osteopontin, in otoconia formation and balance function utilizing its knockout mice, whose inner ear phenotype has not been examined. Despite the presence of the protein in wild-type otoconia and vestibular hair cells, morphological, ultrastructural, and protein and calcium composition analyses of osteopontin null otoconia show that the protein is not needed for crystal formation, and no evidence of compensatory protein deposition is found. Employment of a wide spectrum of balance behavioral tests demonstrates that the protein is not critical for balance function either, which is confirmed by the normal function of the gravity receptor organ directly measured with linear vestibular-evoked potentials (VsEPs). When compared with findings on other otoconins, the data manifest a hierarchy of importance of proteins in crystallization and indicate mechanistic similarities and differences between bone and otoconia calcification.

KW - Balance behaviors

KW - Bone

KW - Calcification

KW - Vestibular-evoked potentials

UR - http://www.scopus.com/inward/record.url?scp=44449136661&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=44449136661&partnerID=8YFLogxK

U2 - 10.1007/s10162-008-0117-z

DO - 10.1007/s10162-008-0117-z

M3 - Article

VL - 9

SP - 191

EP - 201

JO - JARO - Journal of the Association for Research in Otolaryngology

JF - JARO - Journal of the Association for Research in Otolaryngology

SN - 1525-3961

IS - 2

ER -