Mixing model systems: using zebrafish and mouse inner ear mutants and other organ systems to unravel the mystery of otoconial development

Brain Res. 2006 May 26;1091(1):58-74. doi: 10.1016/j.brainres.2006.01.074. Epub 2006 Mar 9.

Abstract

Human vestibular dysfunction is an increasing clinical problem. Degeneration or displacement of otoconia is a significant etiology of age-related balance disorders and Benign Positional Vertigo (BPV). In addition, commonly used antibiotics, such as aminoglycoside antibiotics, can lead to disruption of otoconial structure and function. Despite such clinical significance, relatively little information has been compiled about the development and maintenance of otoconia in humans. Recent studies in model organisms and other mammalian organ systems have revealed some of the proteins and processes required for the normal biomineralization of otoconia and otoliths in the inner ear of vertebrates. Orchestration of extracellular biomineralization requires bringing together ionic and proteinaceous components in time and space. Coordination of these events requires the normal formation of the otocyst and sensory maculae, specific secretion and localization of extracellular matrix proteins, as well as tight regulation of the endolymph ionic environment. Disruption of any of these processes can lead to the formation of abnormally shaped, or ectopic, otoconia, or otoconial agenesis. We propose that normal generation of otoconia requires a complex temporal and spatial control of developmental and biochemical events. In this review, we suggest a new hypothetical model for normal otoconial and otolith formation based on matrix vesicle mineralization in bone which we believe to be supported by information from existing mutants, morphants, and biochemical studies.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Animals
  • Calcification, Physiologic
  • Calcium / metabolism
  • Endolymph / physiology
  • Epithelium / physiology
  • Humans
  • Mice
  • Mice, Mutant Strains / physiology
  • Models, Animal*
  • Models, Biological
  • Olfactory Marker Protein / metabolism
  • Otolithic Membrane / cytology
  • Otolithic Membrane / growth & development*
  • Otolithic Membrane / physiology*
  • Zebrafish / physiology

Substances

  • Olfactory Marker Protein
  • Calcium