Search

Your search keyword '"Defourny, Jean"' showing total 26 results
Start Over Author "Defourny, Jean"
26 results on '"Defourny, Jean"'

6. Recent insights into gap junction biogenesis in the cochlea.

Author

Defourny, Jean and Thiry, Marc

Subjects
COCHLEA, RECESSIVE genes, ADHERENS junctions, EPITHELIAL cells, HEARING disorders, CAVEOLAE
Abstract

In the cochlea, connexin 26 (Cx26) and connexin 30 (Cx30) co‐assemble into two types of homomeric and heteromeric gap junctions between adjacent non‐sensory epithelial cells. These channels provide a mechanical coupling between connected cells, and their activity is critical to maintain cochlear homeostasis. Many of the mutations in GJB2 or GJB6, which encode Cx26 and Cx30 in humans, impair the formation of membrane channels and cause autosomal syndromic and non‐syndromic hearing loss. Thus, deciphering the connexin trafficking pathways in situ should represent a major step forward in understanding the pathogenic significance of many of these mutations. A growing body of evidence now suggests that Cx26/Cx30 heteromeric and Cx30 homomeric channels display distinct assembly mechanisms. Here, we review the most recent advances that have been made toward unraveling the biogenesis and stability of these gap junctions in the cochlea. Key Findings: Cx26/Cx30 heteromeric and Cx30 homomeric channels display distinct assembly mechanismsCadherin‐based tricellular adherens junctions promote the microtubule‐mediated trafficking of Cx26/Cx30 oligomers to the cell surface and further assembly into GJPsEphrin‐B2 promotes the assembly and sequestration of Cx30 GJPs into caveolae membrane domains in a cell‐autonomous manner [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

10. Contributors

Author

Alexander, Erika E., primary, Altieri, Stefanie C., additional, Avraham, Karen B., additional, Bardhan, Tanaya, additional, Baxendale, Sarah, additional, Beraneck, Mathieu, additional, Bhonker, Yoni, additional, Cardon, Garrett, additional, Chen, Ping, additional, Clause, Amanda, additional, Contreras, Julio, additional, Corns, Laura F., additional, Defourny, Jean, additional, Delacroix, Laurence, additional, Duncan, Jeremy S., additional, Fritzsch, Bernd, additional, Grimsley-Myers, Cynthia M., additional, Hashino, Eri, additional, Holley, Matthew C., additional, Horn, Eberhard R., additional, Houston, Oliver, additional, Jarman, Andrew P., additional, Johnson, Stuart L., additional, Kandler, Karl, additional, Koehler, Karl R., additional, Kopecky, Benjamin J., additional, Lambert, François M., additional, Lopez-Poveda, Enrique A., additional, Magariños, Marta, additional, Malgrange, Brigitte, additional, Malone, Alexander K., additional, Marcotti, Walter, additional, Maricich, Stephen M., additional, Masetto, Sergio, additional, Olt, Jennifer, additional, Peusner, Kenna D., additional, Rida, Padmashree C.G., additional, Sadeghi, Soroush G., additional, Sharma, Anu, additional, Simmons, Andrea Megela, additional, Sturm, Joshua, additional, Ushakov, Kathy, additional, Varela-Nieto, Isabel, additional, and Whitfield, Tanya T., additional

Published
2014
Full Text
View/download PDF

11. Visualization of Chromatin in the Yeast Nucleus and Nucleolus Using Hyperosmotic Shock

Author

Thelen, Nicolas, Defourny, Jean, Lafontaine, Denis, and Thiry, Marc

Subjects
Cell Nucleus, perichromatin granules, electron cytochemistry, Histocytochemistry, nucleus, Saccharomyces cerevisiae, yeast, Chromatin Assembly and Disassembly, Article, lcsh:Chemistry, Microscopy, Electron, Transmission, lcsh:Biology (General), lcsh:QD1-999, immunoelectron microscopy, Osmotic Pressure, Heterochromatin, chromatin, Biologie cellulaire, nucleolus, lcsh:QH301-705.5, Cell Nucleolus
Abstract

Unlike in most eukaryotic cells, the genetic information of budding yeast in the exponential growth phase is only present in the form of decondensed chromatin, a configuration that does not allow its visualization in cell nuclei conventionally prepared for transmission electron microscopy. In this work, we studied the distribution of chromatin and its relationships to the nucleolus using different cytochemical and immunocytological approaches applied to yeast cells subjected to hyperosmotic shock. Our results show that osmotic shock induces the formation of heterochromatin patches in the nucleoplasm and intranucleolar regions of the yeast nucleus. In the nucleolus, we further revealed the presence of osmotic shock-resistant DNA in the fibrillar cords which, in places, take on a pinnate appearance reminiscent of ribosomal genes in active transcription as observed after molecular spreading (&ldquo, Christmas trees&rdquo, ). We also identified chromatin-associated granules whose size, composition and behaviour after osmotic shock are reminiscent of that of mammalian perichromatin granules. Altogether, these data reveal that it is possible to visualize heterochromatin in yeast and suggest that the yeast nucleus displays a less-effective compartmentalized organization than that of mammals.

Published
2021

20. Hypervulnerability to Sound Exposure through Impaired Adaptive Proliferation of Peroxisomes

Author

Delmaghani, Sedigheh, primary, Defourny, Jean, additional, Aghaie, Asadollah, additional, Beurg, Maryline, additional, Dulon, Didier, additional, Thelen, Nicolas, additional, Perfettini, Isabelle, additional, Zelles, Tibor, additional, Aller, Mate, additional, Meyer, Anaïs, additional, Emptoz, Alice, additional, Giraudet, Fabrice, additional, Leibovici, Michel, additional, Dartevelle, Sylvie, additional, Soubigou, Guillaume, additional, Thiry, Marc, additional, Vizi, E. Sylvester, additional, Safieddine, Saaid, additional, Hardelin, Jean-Pierre, additional, Avan, Paul, additional, and Petit, Christine, additional

Published
2015
Full Text
View/download PDF

22. Ephrin-A5/EphA4 signalling controls specific afferent targeting to cochlear hair cells

Author

Defourny, Jean, Poirrier, Anne-Lise, Lallemend, Francois, Sanchez, Susana Mateo, Neef, Jakob, Vanderhaeghen, Pierre, Soriano, Eduardo, Peuckert, Christiane, Kullander, Klas, Fritzsch, Bernd, Nguyen, Laurent, Moonen, Gustave, Moser, Tobias, Malgrange, Brigitte, Defourny, Jean, Poirrier, Anne-Lise, Lallemend, Francois, Sanchez, Susana Mateo, Neef, Jakob, Vanderhaeghen, Pierre, Soriano, Eduardo, Peuckert, Christiane, Kullander, Klas, Fritzsch, Bernd, Nguyen, Laurent, Moonen, Gustave, Moser, Tobias, and Malgrange, Brigitte

Abstract

Hearing requires an optimal afferent innervation of sensory hair cells by spiral ganglion neurons in the cochlea. Here we report that complementary expression of ephrin-A5 in hair cells and EphA4 receptor among spiral ganglion neuron populations controls the targeting of type I and type II afferent fibres to inner and outer hair cells, respectively. In the absence of ephrin-A5 or EphA4 forward signalling, a subset of type I projections aberrantly overshoot the inner hair cell layer and invade the outer hair cell area. Lack of type I afferent synapses impairs neurotransmission from inner hair cells to the auditory nerve. By contrast, radial shift of type I projections coincides with a gain of presynaptic ribbons that could enhance the afferent signalling from outer hair cells. Ephexin-1, cofilin and myosin light chain kinase act downstream of EphA4 to induce type I spiral ganglion neuron growth cone collapse. Our findings constitute the first identification of an Eph/ephrin-mediated mutual repulsion mechanism responsible for specific sorting of auditory projections in the cochlea.

Published
2013
Full Text
View/download PDF

23. Ephrin-A5/EphA4 signalling controls specific afferent targeting to cochlear hair cells

Author

Defourny, Jean, primary, Poirrier, Anne-Lise, additional, Lallemend, François, additional, Mateo Sánchez, Susana, additional, Neef, Jakob, additional, Vanderhaeghen, Pierre, additional, Soriano, Eduardo, additional, Peuckert, Christiane, additional, Kullander, Klas, additional, Fritzsch, Bernd, additional, Nguyen, Laurent, additional, Moonen, Gustave, additional, Moser, Tobias, additional, and Malgrange, Brigitte, additional

Published
2013
Full Text
View/download PDF

26. Structure and development of cochlear afferent innervation in mammals.

Author

Defourny J, Lallemend F, and Malgrange B

Subjects
Animals, Cochlea growth & development, Hearing physiology, Neurons, Afferent physiology, Synapses physiology, Cochlea innervation, Mammals anatomy & histology, Neurons, Afferent cytology
Abstract

In mammals, sensorineural deafness results from damage to the auditory receptors of the inner ear, the nerve pathways to the brain or the cortical area that receives sound information. In this review, we first focused on the cellular and molecular events taking part to spiral ganglion axon growth, extension to the organ of Corti, and refinement. In the second half, we considered the functional maturation of synaptic contacts between sensory hair cells and their afferent projections. A better understanding of all these processes could open insights into novel therapeutic strategies aimed to re-establish primary connections from sound transducers to the ascending auditory nerve pathways.

Published
2011
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results