Molecular architecture underlying fluid absorption by the developing inner ear
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE87293 | GEO | 2017/09/11
SECONDARY ACCESSION(S): PRJNA344028
REPOSITORIES: GEO
Similar Datasets
Project description:Mutations of SLC26A4 are a common cause of hearing loss associated with enlargement of the endolymphatic sac (EES). Slc26a4 expression in the developing mouse endolymphatic sac is required for acquisition of normal inner ear structure and function. Here, we show that the mouse endolymphatic sac absorbs fluid in an SLC26A4-dependent fashion. Fluid absorption was sensitive to ouabain and gadolinium but insensitive to benzamil, bafilomycin and S3226. Single-cell RNA-seq analysis of pre- and postnatal endolymphatic sacs demonstrates two types of differentiated cells. Early ribosome-rich cells (RRCs) have a transcriptomic signature suggesting expression and secretion of extracellular proteins, while mature RRCs express genes implicated in innate immunity. The transcriptomic signature of mitochondria-rich cells (MRCs) indicates that they mediate vectorial ion transport. We propose a molecular mechanism for resorption of NaCl by MRCs during development, and conclude that disruption of this mechanism is the root cause of hearing loss associated with EES.
| S-EPMC5634787 | biostudies-literature
Project description:The embryonic endolymphatic sac mediates fluid resorption for which anion exchangers such as SLC26A4, and its transcriptional activator FOXI1, are required. Apart from FOXI1, little is known about transcriptional regulators of this fluid balance. Altered fluid homeostasis in the inner ear is the leading cause of congenital hearing loss. Some patients with campomelic dysplasia (CD) caused by heterozygous mutations in SOX9, in addition to skeletal malformation, are deaf, with an unknown etiology. In a mouse model of CD caused by the SOX9Y440X mutation, which results in a truncated protein lacking the transactivation domain, we show severe endolymphatic dysfunction leading to deafness and vestibular problems. Adult heterozygous Sox9Y440X mice that express the mutation in the developing inner ear display sensorineural deafness combined with endolymphatic hydrops and lack of endocochlear potential. The mutant inner ear is enlarged from E15 and fewer Slc26a4-expressing cells are present in the endolymphatic epithelium. By single cell RNA sequencing of mutant and wild-type endolymphatic sacs we find marked reduction in genes important for ion transport such as Slc24a4 and Ttyh1 and gap-junctions such as Gjb2 and up-regulation of Wnt signaling and Igfbp2 that promotes progenitor proliferation. The cochlea overexpresses Aqp3, which encodes a water channel. We find by biochemical and cell-based transactivation assays and genetic interaction tests that SOX9 and SOX10 normally work co-operatively to repress Aqp3 transcription: SOX9Y440X blocks this repression by dominant interference. Our study reveals the key roles of SOXE transcription factors in the development of endolymphatic sac function, and highlight a molecular mechanism whereby the CD mutation exerts both a dominant negative and haploinsufficient mechanisms in different compartments of the inner ear to maintain fluid homeostasis. In the cochlea, SOX9 and SOX10 together repress aquaporin expression whereas in the endolymphatic sac, SOX9 controls SOX10 expression and genes for ion transport and gap-junctions. We postulate that in addition to loss of control of cell proliferation results in the exhaustion of progenitors which in turn leads to a deficit in mitochondria-rich cells. These results highlight a multifaceted mechanism for maintaining the proper fluid balance for hearing.
2022-10-10 | GSE131196 | GEO
Project description:The embryonic endolymphatic sac mediates fluid resorption for which anion exchangers such as SLC26A4, and its transcriptional activator FOXI1, are required. Apart from FOXI1, little is known about transcriptional regulators of this fluid balance. Altered fluid homeostasis in the inner ear is the leading cause of congenital hearing loss. Some patients with campomelic dysplasia (CD) caused by heterozygous mutations in SOX9, in addition to skeletal malformation, are deaf, with an unknown etiology. In a mouse model of CD caused by the SOX9Y440X mutation, which results in a truncated protein lacking the transactivation domain, we show severe endolymphatic dysfunction leading to deafness and vestibular problems. Adult heterozygous Sox9Y440X mice that express the mutation in the developing inner ear display sensorineural deafness combined with endolymphatic hydrops and lack of endocochlear potential. The mutant inner ear is enlarged from E15 and fewer Slc26a4-expressing cells are present in the endolymphatic epithelium. By single cell RNA sequencing of mutant and wild-type endolymphatic sacs we find marked reduction in genes important for ion transport such as Slc24a4 and Ttyh1 and gap-junctions such as Gjb2 and up-regulation of Wnt signaling and Igfbp2 that promotes progenitor proliferation. The cochlea overexpresses Aqp3, which encodes a water channel. We find by biochemical and cell-based transactivation assays and genetic interaction tests that SOX9 and SOX10 normally work co-operatively to repress Aqp3 transcription: SOX9Y440X blocks this repression by dominant interference. Our study reveals the key roles of SOXE transcription factors in the development of endolymphatic sac function, and highlight a molecular mechanism whereby the CD mutation exerts both a dominant negative and haploinsufficient mechanisms in different compartments of the inner ear to maintain fluid homeostasis. In the cochlea, SOX9 and SOX10 together repress aquaporin expression whereas in the endolymphatic sac, SOX9 controls SOX10 expression and genes for ion transport and gap-junctions. We postulate that in addition to loss of control of cell proliferation results in the exhaustion of progenitors which in turn leads to a deficit in mitochondria-rich cells. These results highlight a multifaceted mechanism for maintaining the proper fluid balance for hearing.
2022-10-10 | GSE139587 | GEO
Project description:The inner ear constitutes different cell types next to one another: the sensory patches whose hair cells synapse with neurons, the thin channels of three semicircular canals whose perpendicular organization enables detection of directional head rotation, and the endolymphatic duct and sac whose conditional epithelial barrier relieves excess pressure and promotes fluid pressure homeostasis. How the ear’s component cell states are established during development has remained unknown. We use single-cell RNA sequencing to distinguish cell states within the developing ear with wild-type zebrafish embryos and lmx1bb mutants that exhibit defects in canal and sac morphogenesis. We identify the earliest marker for the semicircular canal-genesis zone (ccn1l1), unexpected genes in the endolymphatic sac that suggest a role for tissue contraction in its function (smtnb), parallel gene sets for sensory patches in the neuromast and ear, and a conserved role for cell-cycle pausing (cdkn1bb expression in the canals and sac as previously observed in the developing mouse ear). This atlas provides the most comprehensive transcriptional profiling of the developing inner ear, identifying new molecular leads to understand ear morphogenesis.
2025-10-03 | GSE309286 | GEO
Project description:Comparison of gene expression in rat endolymphatic sac with dura tissue to pure dura tissue.
2010-11-30 | E-MEXP-3022 | biostudies-arrayexpress
Project description:Methylation analysis of sporadic and von Hippel-Lindau syndrome associated endolymphatic sac tumors (ELST).
2021-06-15 | GSE168808 | GEO
Project description:Sensorineural deafness can occur in campomelic dysplasia (CD). In a mouse model of the SOX9Y440X/+ CD mutation, SOX10 downregulation was previously shown to be associated with impaired development of the endolymphatic system at mid-gestation. The underlying molecular causes are unknown. Here we found at E10.5 when the otocyst lacks overt inner ear structures, Sox10 was downregulated in the dorsal and medial aspects of the Sox9Y440X/+ otic epithelium, regions associated with specification of the endolymphatic sac and duct. Single-cell transcriptomic profiling revealed differential elevation of Wnt signaling pathway genes associated with the domain-specific Sox10 reduction. Otocyst-specific forced elevation of Wnt signaling by expression of stabilized β-catenin suppressed Sox10 expression. Similarly, WNT exerted an inhibitory effect on SOX10 expression in human inner ear organoids derived from pluripotent stem cells. We propose a conserved regulatory model of SOX9-WNT antagonism governing SOX10 action in the otocyst underlies the specification of endolymphatic cell fate, with important implications for understanding human deafness syndromes.
2024-11-07 | GSE271849 | GEO
Project description:Methylation profiling of endolymphatic sac tumors
| PRJNA714076 | ENA
Project description:Cellular senescence disables the proliferation of damaged cells and it is relevant for cancer and aging. Here, we show that cellular senescence occurs during mammalian embryonic development. Specifically, we have focused on the mouse regressing mesonephros and the endolymphatic sac of the inner ear. Senescence is characterized by SAM-NM-2G activity, heterochromatinization, and proliferative arrest. Mechanistically, developmentally-programmed senescence at the mesonephros and endolymphatic sac is strictly dependent on p21, but independent of DNA damage, p53 or other cell cycle inhibitors, and it is regulated by the TGFM-NM-2/SMAD and PI3K/FOXO pathways. Developmentally-programmed senescence is followed by macrophage infiltration and clearance of senescent cells. Abrogation of senescence by p21 deletion is only partially compensated by apoptosis and originates detectable developmental abnormalities. Importantly, high levels of p21 are also associated to the regressing mesonephros and endolymphatic sac in human embryos. These findings place cellular senescence as a relevant morphogenic process during embryonic development. We microdissected mesonephric tubules from senescent (WT) and non-senescent (p21-null) embryos to get information about this new senescence that occurs during embryogenesis.
2013-11-14 | E-GEOD-49108 | biostudies-arrayexpress
Project description:Cellular senescence disables the proliferation of damaged cells and it is relevant for cancer and aging. Here, we show that cellular senescence occurs during mammalian embryonic development. Specifically, we have focused on the mouse regressing mesonephros and the endolymphatic sac of the inner ear. Senescence is characterized by SAβG activity, heterochromatinization, and proliferative arrest. Mechanistically, developmentally-programmed senescence at the mesonephros and endolymphatic sac is strictly dependent on p21, but independent of DNA damage, p53 or other cell cycle inhibitors, and it is regulated by the TGFβ/SMAD and PI3K/FOXO pathways. Developmentally-programmed senescence is followed by macrophage infiltration and clearance of senescent cells. Abrogation of senescence by p21 deletion is only partially compensated by apoptosis and originates detectable developmental abnormalities. Importantly, high levels of p21 are also associated to the regressing mesonephros and endolymphatic sac in human embryos. These findings place cellular senescence as a relevant morphogenic process during embryonic development.
2013-11-14 | GSE49108 | GEO