Intermediate Cells of Dual Embryonic Origin Follow a Basal to Apical Gradient of Ingression Into the Lateral Wall of the Cochlea

Abstract

Intermediate cells of the stria vascularis are neural crest derived melanocytes. They are essential for the establishment of the endocochlear potential in the inner ear, which allows mechanosensory hair cells to transduce sound into nerve impulses. Despite their importance for normal hearing, how these cells develop and migrate to their position in the lateral wall of the cochlea has not been studied. We find that as early as E10.5 some Schwann cell precursors in the VIIIth ganglion begin to express melanocyte specific markers while neural crest derived melanoblasts migrate into the otic vesicle. Intermediate cells of both melanoblast and Schwann cell precursor origin ingress into the lateral wall of the cochlea starting at around E15.5 following a basal to apical gradient during embryonic development, and continue to proliferate postnatally.

Development of the stria vascularis in the common marmoset, a primate model

“…Next, we examined the integration and development of intermediate cells of the stria vascularis by evaluating a marker of intermediate cells: melan-A (MLANA). The intermediate cells of the stria vascularis are melanocyte-like cells that originate from the neural crest cells and Schwann cell precursors, which immigrate into the cochlea, integrate into the stria vascularis, and, finally, develop into intermediate cells 14,15,18,19,28 . MLANA encodes a surface protein of melanocytes, Melan-A, whose expression is reported in developing intermediate cells 2 .…”

“…This stria vascularis comprises mainly three layers of cells: the marginal, intermediate, and basal cells 12 . Previous reports reveal that the three layers of the stria vascularis have different origins: the marginal cells are derived from epithelial cells of the cochlear duct that develop from the otocyst, intermediate cells originate from immigrating neural crest cells and Schwann cell precursors, and basal cells differentiate from periotic mesenchymal cells [13][14][15][16][17][18][19] . In addition to these three layers, the stria vascularis contains capillaries that directly influence the composition of the endolymph 12,20 .…”

Incoherent collective cell chemotaxis underlies organ dysmorphia in a model of branchio-oto-renal syndrome

“…Yet, the cellular processes affected by mutations in Eya1 and its effectors remain undefined. Collective cell migration underlies morphogenesis of the inner ear and the kidney, the two main organs affected in BOR patients (Vasilyev et al, 2009; Schumacher, 2019; Ishii et al, 2021; Renauld et al, 2022). Based on our findings, we propose that Eya1 governs coherent collective cell movement during otic and renal development mainly via chemokine signaling.…”

Human pluripotent stem cells-derived inner ear organoids recapitulate otic developmentin vitro

“…Migrating cranial neural crest (CNC) infiltrates the OV and surrounding otic mesenchyme and contributes to the population of glial/Schwann cells in the cochlear and vestibular ganglia (Mendez-Maldonado et al, 2020;Renauld et al, 2022) and to the intermediate cell layer in the stria vascularis (which was not certified by peer review) is the author/funder. All rights reserved.…”

“…The copyright holder for this preprint this version posted April 12, 2023. ; https://doi.org/10.1101/2023.04.11.536448 doi: bioRxiv preprint (Adameyko et al, 2012;Cable et al, 1992;Locher et al, 2015;Renauld et al, 2022;Steel and Barkway, 1989). CNC-derived mesenchyme instead, will give rise to the ossicles of the middle ear (Martik and Bronner, 2021).…”