References of "Francart, Marie-Emilie"
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See detailStudy of the Boettcher cells along their development: Junctions and expression of the urea-transporter B (UT-B)
Cloes, Marie ULg; Renson, Thomas; Johnen, Nicolas ULg et al

Poster (2012, September 30)

The Boettcher cells (BC) lie on the sensory epithelium of the cochlea. Their function has never been clearly defined. However it has been suggested that they may influence the ionic composition of the ... [more ▼]

The Boettcher cells (BC) lie on the sensory epithelium of the cochlea. Their function has never been clearly defined. However it has been suggested that they may influence the ionic composition of the fluids of the inner ear, which play a central role in the conduction of the sensory information. In this context the compartimentating function of the BC around and after the onset of hearing may influence the subsequent refining of hearing. We collected ultrastructural and immunohistological data during the final maturation stage of the sensory epithelium. In particular the cell junctions were investigated to clarify the compartimentating function of the BC at early stages. As a potential actor in the ion flow in the sensory epithelium, the urea transporter-B (UT-B) was also immunolocalised during the development of the BC. At the mature stage (P25) the BC are linked to the adjacent cells by numerous adherens and non-adherens junctions. They rest on a basilar membrane to which they are attached by hemidesmosomes. They typically exhibit large basolateral interdigitations. We found that, at the 8th postnatal day, the BC are separated from the neighbouring cells by wide spaces entered by scarce cytoplasmic extensions. These spaces are interrupted by areas of close contact, where adherens and non-adherens junctions may be found. Thus, although there seems to be fewer interdigitations at P8, gap junctions probably still allow easy cell-to-cell exchanges. Moreover non-adherens junctions can systematically be identified apically. Although it was impossible to differenciate tight and gap junctions without specific labeling, we postulate that these non-adherens junctions correspond to tight junctions and seal the apex of the BC. This feature is necessary to enable the control of the ion concentrations surrounding the sensory epithelium. We also found that UT-B, known for water and urea transport in red blood cells, is present in the membranes of the BC from P12 (the earliest stage tested) to P25. Thus UT-B may play a role in the regulation of the ionic concentrations of the inner ear fluids. [less ▲]

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See detailEvidence for a partial epithelial-mesenchymal transition in postnatal stages of rat auditory organ morphogenesis.
Johnen, Nicolas ULg; Francart, Marie-Emilie ULg; Thelen, Nicolas ULg et al

in Histochemistry & Cell Biology (2012)

The epithelial-mesenchymal transition (EMT) plays a crucial role in the differentiation of many tissues and organs. So far, an EMT was not detected in the development of the auditory organ. To determine ... [more ▼]

The epithelial-mesenchymal transition (EMT) plays a crucial role in the differentiation of many tissues and organs. So far, an EMT was not detected in the development of the auditory organ. To determine whether an EMT may play a role in the morphogenesis of the auditory organ, we studied the spatial localization of several EMT markers, the cell-cell adhesion molecules and intermediate filament cytoskeletal proteins, in epithelium of the dorsal cochlea during development of the rat Corti organ from E18 (18th embryonic day) until P25 (25th postnatal day). We examined by confocal microscopy immunolabelings on cryosections of whole cochleae with antibodies anti-cytokeratins as well as with antibodies anti-vimentin, anti-E-cadherin and anti-β-catenin. Our results showed a partial loss of E-cadherin and β-catenin and a temporary appearance of vimentin in pillar cells and Deiters between P8 and P10. These observations suggest that a partial EMT might be involved in the remodelling of the Corti organ during the postnatal stages of development in rat. [less ▲]

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