The laminins in the murine inner ear: developmental transitions and expression in cochlear basement membranes

Rodgers, Kathyrn D.; Barritt, Laura C.; Miner, J. H.; Cosgrove, Dominic

doi:10.1016/s0378-5955(01)00283-0

Cited by 28 publications

(23 citation statements)

References 55 publications

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“…For instance, hair cells may project to the ECM in pursuit of a molecular signal which they require, but are unable to receive. Interactions with the ECM provide important developmental and functional clues to epithelial cells [Cosgrove et al, 1996;Cosgrove and Rodgers, 1997;Rodgers et al, 2001]. We have shown that cytocauds reach and at times penetrate the basement membrane to make direct contact with the ECM.…”

Section: Discussionmentioning

confidence: 99%

The Cytocaud: A Hair Cell Pathology in the Waltzing Guinea Pig

Kanzaki¹,

Beyer²,

Canlon³

et al. 2002

Audiol Neurotol

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The waltzing guinea pig displays severe inner ear dysfunction that involves both an auditory and a vestibular manifestation. The aim of this study was to characterize a pathological tail-like extension of the vestibular hair cells, the cytocaud. Our data suggest that nearly all type I hair cells in the waltzing guinea pig have cytocauds, which appear as membrane-bound tails containing mitochondria and cytoplasm that proceed in a basal direction toward the basement membrane. The extensions either attach to the basement membrane or penetrate it, and further proceed into the extracellular matrix. A core made of a thick and long (30 µm) actin-rich structure supports the slender long process. The actin core has cross-links that are periodically placed along the length of the cytocaud. Our data suggest that the cytocauds in vestibular hair cells of the waltzing guinea pig are highly organized structures associated with a failure to detach from the basement membrane.

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Section: Discussionmentioning

confidence: 99%

The Cytocaud: A Hair Cell Pathology in the Waltzing Guinea Pig

Kanzaki¹,

Beyer²,

Canlon³

et al. 2002

Audiol Neurotol

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“…After investigating the effects of the individual ECM proteins LN and FN on SGN neurite extension by comparison against PLL-control, we then examined the effects of direct competition between LN and FN, by alternating stripes of the two ECM molecules, since the two ECM molecules occur in nonidentical patterns in the perinatal organ of Corti (Woolf et al, 1992;Cosgrove and Rodgers, 1997;Rodgers et al, 2001). By immunofluoresence staining of the stripes, little deposition of the second ECM protein onto the stripes of the first ECM protein was observed (see Methods section).…”

Section: Sg Neurites On Stripes Of Fn Versus Lnmentioning

confidence: 99%

“…The SG is centrally located in the modiolus, while the mechanosensory target cells, inner and outer hair cells (HCs), are located peripherally on the basilar membrane. The ECM molecule laminin (LN), a heterotrimer of a, b, and c chains, has been identified in the mammalian cochlea in the basement membranes surrounding the developing SG and underlying the basilar membrane (Cosgrove and Rodgers, 1997;Rodgers et al, 2001). During postnatal maturation of the organ of Corti, a change in expression of LN heterotrimer subunits occurs at the same time as the SG dendrites target the HCs (Cosgrove and Rodgers, 1997;Rodgers et al, 2001), suggesting a possible functional linkage of LN to postnatal SG differentiation and dendrite targeting.…”

Section: Introductionmentioning

confidence: 99%

“…The ECM molecule laminin (LN), a heterotrimer of a, b, and c chains, has been identified in the mammalian cochlea in the basement membranes surrounding the developing SG and underlying the basilar membrane (Cosgrove and Rodgers, 1997;Rodgers et al, 2001). During postnatal maturation of the organ of Corti, a change in expression of LN heterotrimer subunits occurs at the same time as the SG dendrites target the HCs (Cosgrove and Rodgers, 1997;Rodgers et al, 2001), suggesting a possible functional linkage of LN to postnatal SG differentiation and dendrite targeting. Another major ECM molecule, the dimeric glycoprotein fibronectin (FN), has also been identified in the mammalian cochlea (Woolf et al, 1992;Cosgrove and Rodgers, 1997).…”

Section: Introductionmentioning

confidence: 99%

“…On homogenous LN surfaces, SG neurites showed a dose-dependent increase in length and number of neurites with increasing LN concentrations (Aletsee et al, 2001). However, in some areas of the inner ear, such as the osseus spiral lamina, ECMs appear to be present in more or less continuous surfaces (Woolf et al, 1992;Rodgers et al, 2001). In the organ of Corti, the target tissue for the SG dendrites, they appear to be present in stripes or tracks, and more than one ECM is present (Woolf et al, 1992;Cosgrove and Rodgers, 1997), suggesting that the differential composition of the ECM in the cochlea could provide guidance cues to SG dendrites.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Laminin and fibronectin modulate inner ear spiral ganglion neurite outgrowth in an in vitro alternate choice assay

Evans

Euteneuer

Chávez

et al. 2007

Developmental Neurobiology

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Extracellular matrix (ECM) molecules have been shown to function as cues for neurite guidance in various populations of neurons. Here we show that laminin (LN) and fibronectin (FN) presented in stripe micro-patterns can provide guidance cues to neonatal (P5) inner ear spiral ganglion (SG) neurites. The response to both ECM molecules was dose-dependent. In a LN versus poly-L-lysine (PLL) assay, neurites were more often observed on PLL at low coating concentrations (5 and 10 microg/mL), while they were more often on LN at a high concentration (80 microg/mL). In a FN versus PLL assay, neurites were more often on PLL than on FN stripes at high coating concentrations (40 and 80 microg/mL). In a direct competition between LN and FN, neurites were observed on LN significantly more often than on FN at both 10 and 40 microg/mL. The data suggest a preference by SG neurites for LN at high concentrations, as well as avoidance of both LN at low and FN at high concentrations. The results also support a potential model for neurite guidance in the developing inner ear in vivo. LN, in the SG and osseus spiral lamina may promote SG dendrite growth toward the organ of Corti. Within the organ of Corti, lower concentrations of LN may slow neurite growth, with FN beneath each row of hair cells providing a stop or avoidance signal. This could allow growth cone filopodia increased time to sample their cellular targets, or direct the fibers upward toward the hair cells.

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Differential expression of α3 and α6 integrins in the developing mouse inner ear

Davies

Holley²

2002

J of Comparative Neurology

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The development of the mammalian inner ear involves a complex series of cell-cell and cell-extracellular matrix interactions. These interactions are likely to be mediated by families of adhesion molecules, including the integrins. We have studied the expression of three integrin subunits known to be expressed on epithelia in a number of tissues (namely, alpha3, alpha6, and beta4) during the development of the murine inner ear. At E10.5, both alpha3 and alpha6 were expressed in the epithelial layers of the otocyst. The expression of alpha6 was concentrated in an anterioventral region of the epithelium and in a proportion of the cells forming the cochlear-vestibular and facial ganglia. By E12.5, alpha6 showed a more restricted expression, confined mainly to the pro-sensory epithelia and the neural processes from the cochlear-vestibular ganglion. In contrast, alpha3 was expressed in epithelia adjacent to the pro-sensory areas. This reciprocal expression pattern was maintained until birth. Between birth and P6, a switch in expression occurred such that alpha3 was upregulated and alpha6 was downregulated in the sensory epithelia of both the auditory and vestibular systems. At this stage, alpha3 was expressed in all the epithelia lining the scala media, thus defining the endolymph compartment. The expression of beta4 was restricted to epithelial/mesenchymal borders throughout the developmental stages studied, suggesting that alpha6 expression observed within the epithelium and neuronal tissue was alpha6beta1. The early expression and changing pattern of alpha3 and alpha6 integrins during development of the mammalian inner ear suggests that they may be involved in the molecular processes that define epithelial boundaries and guide sensory innervation.

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The laminins in the murine inner ear: developmental transitions and expression in cochlear basement membranes

Cited by 28 publications

References 55 publications

The Cytocaud: A Hair Cell Pathology in the Waltzing Guinea Pig

The Cytocaud: A Hair Cell Pathology in the Waltzing Guinea Pig

Laminin and fibronectin modulate inner ear spiral ganglion neurite outgrowth in an in vitro alternate choice assay

Differential expression of α3 and α6 integrins in the developing mouse inner ear

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