A 'Tric' to tighten cell-cell junctions in the cochlea for hearing
| Autor: | Tomohito Higashi, Danielle R. Lenz, Mikio Furuse, Karen B. Avraham |
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| Rok vydání: | 2013 |
| Předmět: |
Male
medicine.medical_specialty Endolymph Endocochlear potential Hearing loss General Medicine Audiology Biology Perilymph Cell junction Tight Junctions Hair Cells Auditory Outer MARVEL Domain Containing 2 Protein medicine.anatomical_structure otorhinolaryngologic diseases medicine Animals Female Inner ear sense organs medicine.symptom Hearing Loss Transduction (physiology) Cochlea Research Article |
| Zdroj: | Journal of Clinical Investigation. 123:3712-3715 |
| ISSN: | 0021-9738 |
| DOI: | 10.1172/jci69651 |
| Popis: | The two compositionally distinct extracellular cochlear fluids, endolymph and perilymph, are separated by tight junctions that outline the scala media and reticular lamina. Mutations in TRIC (also known as MARVELD2), which encodes a tricellular tight junction protein known as tricellulin, lead to nonsyndromic hearing loss (DFNB49). We generated a knockin mouse that carries a mutation orthologous to the TRIC coding mutation linked to DFNB49 hearing loss in humans. Tricellulin was absent from the tricellular junctions in the inner ear epithelia of the mutant animals, which developed rapidly progressing hearing loss accompanied by loss of mechanosensory cochlear hair cells, while the endocochlear potential and paracellular permeability of a biotin-based tracer in the stria vascularis were unaltered. Freeze-fracture electron microscopy revealed disruption of the strands of intramembrane particles connecting bicellular and tricellular junctions in the inner ear epithelia of tricellulin-deficient mice. These ultrastructural changes may selectively affect the paracellular permeability of ions or small molecules, resulting in a toxic microenvironment for cochlear hair cells. Consistent with this hypothesis, hair cell loss was rescued in tricellulin-deficient mice when generation of normal endolymph was inhibited by a concomitant deletion of the transcription factor, Pou3f4. Finally, comprehensive phenotypic screening showed a broader pathological phenotype in the mutant mice, which highlights the non-redundant roles played by tricellulin. |
| Databáze: | OpenAIRE |
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