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Disruption of ephrin B/Eph B interaction results in abnormal cochlear innervation patterns
Author(s) -
Zhou Constance Q.,
Lee James,
Henkemeyer Mark J.,
Lee Kenneth H.
Publication year - 2011
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1002/lary.21861
Subject(s) - spiral ganglion , erythropoietin producing hepatocellular (eph) receptor , cochlea , ephrin , organ of corti , biology , knockout mouse , microbiology and biotechnology , inner ear , ganglion , anatomy , receptor , signal transduction , genetics , receptor tyrosine kinase
Objective: To determine the expression patterns of B ephrins and Ephs in the cochlea and identify functional consequences of disruption of ephrin B/Eph B interactions in both cultured spiral ganglion neurons and in the cochlea of live animals. Study Design: The expression patterns of various B ephrins and Ephs were determined in mice with Lac‐Z mutation. Mice with null function of individual B ephrin and Eph proteins and those with multiple knockouts were studied for cochlear innervation patterns. Methods: Mice with B ephrins and Ephs disrupted with the β‐galactosidase gene were sacrificed at P6, and their cochleae isolated and processed for Lac‐Z staining to determine expression of these proteins in cochlear tissue. Spiral ganglion cells from wild‐type as well as ephrin B1 knockout mice were isolated and cocultured with Eph B2 expressing Cos1 cells and neurite lengths were determined. Fluorescent lipophillic dyes were used to label spiral ganglion cell nerve fibers to determine cochlear innervation patterns in wild‐type and knockout mice. Results: Eph B1, B2, and ephrin B2 but not B3 was expressed in the cochlea. Eph B2 inhibited outgrowth of spiral ganglion cell axons from wild‐type mice, but not from ephrin B1 knockout mice in culture. Knockout mice with null function of ephrin B1 alone or Eph B1, Eph B2, Eph B3 in combination demonstrated abnormal innervation patterns in the organ of Corti. Conclusions: Disruption of B ephrins and Ephs results in functional consequences in spiral ganglion cells, suggesting that these proteins play a role in establishing normal innervation patterns in the cochlea.