Lamellar projections in the endolymphatic sac act as a relief valve to regulate inner ear pressure.

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eLife. 2018 Jun 19;7. doi: 10.7554/eLife.37131

Lamellar projections in the endolymphatic sac act as a relief valve to regulate inner ear pressure. Betzig Lab

Swinburne IA, Mosaliganti KR, Upadhyayula S, Liu T, Hildebrand DG, Tsai TY, Chen A, Al-Obeidi E, Fass AK, Malhotra S, Engert F, Lichtman JW, Kirchausen T, Betzig E, Megason SG

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Abstract

The inner ear is a fluid-filled closed-epithelial structure whose function requires maintenance of an internal hydrostatic pressure and fluid composition. The endolymphatic sac (ES) is a dead-end epithelial tube connected to the inner ear whose function is unclear. ES defects can cause distended ear tissue, a pathology often seen in hearing and balance disorders. Using live imaging of zebrafish larvae, we reveal that the ES undergoes cycles of slow pressure-driven inflation followed by rapid deflation. Absence of these cycles in mutants leads to distended ear tissue. Using serial-section electron microscopy and adaptive optics lattice light-sheet microscopy, we find a pressure relief valve in the ES comprised of partially separated apical junctions and dynamic overlapping basal lamellae that separate under pressure to release fluid. We propose that this lmx1-dependent pressure relief valve is required to maintain fluid homeostasis in the inner ear and other fluid-filled cavities.

PMID: 29916365 [PubMed - indexed for MEDLINE]

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Lamellar projections in the endolymphatic sac act as a relief valve to regulate inner ear pressure.

Abstract

PMID: 29916365 [PubMed - indexed for MEDLINE]

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