Opposing activity of SOX9 and Wnt in the developing otocyst ensures SOX10 control of endolymphatic development
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE271849 | GEO | 2024/11/07
REPOSITORIES: GEO
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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 otic placode, from which the inner ear develops, initially forms as a thickened ectodermal patch adjacent to the dorsolateral hindbrain. Induction of otic placodal cells from human pluripotent stem cells (hPSCs) provides a robust approach to investigation of otic development. However, attempts to recapitulate otic lineage specification from hPSCs by stepwise differentiation methods have had limited success. One possible reason is that the role of signaling pathways in otic cell differentiation is not fully understood. Here, we developed a novel differentiation system involving use of suspension culture (3D floating culture) in combination with signaling factors for generating otic placodal cells via stepwise differentiation of hPSCs. We demonstrate that hPSC-derived pre-placodal cells acquired the potential to differentiate into posterior placodal cells after fibroblast growth factor 2 (FGF2) and retinoic acid (RA) treatment. Subsequent activation of WNT signaling following posterior placode specification induced differentiation of SIX1+/PAX8+/SOX2+ otic placodal cells. qPCR analysis showed that WNT activation increased expression of otocyst markers, including PAX8, PAX2, DLX5 and FBXO2. Moreover, induced otic cells exhibited similar gene expression patterns to the ventral and medial portions of the otocyst that give rise to the sensory epithelium of the inner ear. Collectively, our results indicate a critical role for FGF2, RA, and WNT signaling for the in vitro differentiation of the otic cell lineage from hPSCs. Our new culture system paves the way for improved modeling of early human inner ear development and will be of value to studies on the further differentiation of sensory epithelial cells.
2022-02-01 | GSE175998 | GEO
Project description:The inner ear arises from multipotent placodal precursors that are gradually committed to the otic fate and further differentiate into all inner ear cell types, with the exception of a few neural crest-derived cells. The otocyst has a pivotal role during inner ear development: otic progenitor cells sub-compartmentalize into non-sensory regions and regions giving rise to prosensory domains where subsequently also hair cells differentiate. The genes and pathways underlying this progressive subdivision and differentiation process are not entirely known. The goal of this study was to identify a comprehensive set of genes expressed in the chicken otocyst using the serial analysis of gene expression (SAGE) method. Our analysis revealed several hundred transcriptional regulators, potential signaling proteins, and receptors. We identified a substantial collection of genes that were previously known in the context of inner ear development, but we also found many new candidate genes, such as Sox4, Sox5, Sox7, Sox8, Sox11, and Sox18, which previously were not known to be expressed in the developing inner ear. Despite its obvious limitation of not being all-inclusive, the generated otocyst SAGE library is a practical bioinformatics tool to study otocyst gene expression and to identify candidate genes for developmental studies.
2011-03-01 | GSE27176 | GEO
Project description:The inner ear arises from multipotent placodal precursors that are gradually committed to the otic fate and further differentiate into all inner ear cell types, with the exception of a few neural crest-derived cells. The otocyst has a pivotal role during inner ear development: otic progenitor cells sub-compartmentalize into non-sensory regions and regions giving rise to prosensory domains where subsequently also hair cells differentiate. The genes and pathways underlying this progressive subdivision and differentiation process are not entirely known. The goal of this study was to identify a comprehensive set of genes expressed in the chicken otocyst using the serial analysis of gene expression (SAGE) method. Our analysis revealed several hundred transcriptional regulators, potential signaling proteins, and receptors. We identified a substantial collection of genes that were previously known in the context of inner ear development, but we also found many new candidate genes, such as Sox4, Sox5, Sox7, Sox8, Sox11, and Sox18, which previously were not known to be expressed in the developing inner ear. Despite its obvious limitation of not being all-inclusive, the generated otocyst SAGE library is a practical bioinformatics tool to study otocyst gene expression and to identify candidate genes for developmental studies. Otocysts were dissected from HH stage 18-19 chicken embryos, total RNA was extracted, and subjected to a commercial long-SAGE protocol, resulting in a library of concatemerized tags. 3,512 individual clones of SAGE concatemers were sequenced resulting in 39,326 17-bp tags with tag counts up to 718 for the most abundant tag; 3,292 tags that were represented between two and five times, whereas the majority of tags (11,717) were only found once. Overall, we identified 16,008 unique sequence tags.
2011-03-01 | E-GEOD-27176 | biostudies-arrayexpress
Project description:Deafness is the most common form of sensory impairment in humans and frequently caused by defects in hair cells of the inner ear. Here we demonstrate that in a mouse model for recessive non-syndromic deafness (DFNB6), inactivation of Tmie in hair cells disrupts gene expression in the neurons that innervate them. This includes genes regulating axonal pathfinding and synaptogenesis, two processes that are disrupted in the inner ear of the mutant mice. Similar defects are observed in mouse models for deafness caused by mutations in other genes with primary functions in hair cells. Gene therapy targeting hair cells restores hearing and inner ear circuitry in DFNB6 model mice. We conclude that hair cell function is crucial for the establishment of peripheral auditory circuitry. Treatment modalities for deafness thus need to consider restoration of the function of both hair cells and neurons, even when the primary defect occurs in hair cells.
2024-11-10 | GSE281207 | GEO
Project description:We established a novel EGFP reporter mouse line (named Tg(ETAR-EGFP)14Imeg), which enables the placode-derived inner ear sensory cell lineage to be visualized and monitored. At E10.5, EGFP expression was detected in the ventral and dorsomedial region of the otocyst. Using this reporter line and FACS-array technology, we performed gene expression profiling focused on the regional specificity of the otocyst. We sorted E10.5 otocyst epithelial cells of heterozygous mice into EGFP-positive and EGFP-negative cells for RNA extraction and hybridization on Affymetrix microarrays. We profiled the expression of the genes in FACS-enriched cell population and conducted transcriptome analysis.
2011-05-23 | E-GEOD-19618 | biostudies-arrayexpress
Project description:Waardenburg syndrome (WS) is a autosomal dominant inherited disorder characterized by sensorineural hearing loss (SNHL) and pigment abnormalities. SOX10 is one of its main pathogenicity genes. In vitro generation of patient-specific induced pluripotent stem cells (iPSCs) is an effective approach for exploring the mechanisms of human disease. Here, we established an iPSCs from a WS patient with SOX10 mutation and differentiated it into induced neural crest cells (NCCs), the key cell type involves in inner ear development. Compared with control-derived iPSCs, the SOX10 mutant iPSCs showed significantly decreased efficiency of development and differentiation potential at the stage of NCCs. We then performed high-throughput RNA-seq and examined the transcriptional misregulation at each stage. The transcriptome analysis differentiated NCCs reveals widespread gene expression changes and the differentially expressed genes(DEGs) were enriched with gene ontology (GO) of neuron migration, skeletal system development, multicellular organism development, which indicate the important role of SOX10 plays in the differentiation of NCCs. It's worth noting that, a significant enrichment among the nominal DEGs for genes implicated in inner ear development was found, as well as several genes related to the inner ear morphogenesis. Based on protein-protein interaction（PPI）net work, we selected four candidate genes that may be regulated by SOX10 in inner ear development: BMP2, LGR5, GBX2 and GATA3. In conclusion, the SOX10 deficiency in this WS patient has a significant impact on the gene expression patterns during the development of NCCs. The DEGs most significantly enriched the inner ear development and morphogenesis could help explain the underlying basis for the inner ear malformation seen in WS patient.
2021-06-04 | GSE176101 | GEO
Project description:We established a novel EGFP reporter mouse line (named Tg(ETAR-EGFP)14Imeg), which enables the placode-derived inner ear sensory cell lineage to be visualized and monitored. At E10.5, EGFP expression was detected in the ventral and dorsomedial region of the otocyst. Using this reporter line and FACS-array technology, we performed gene expression profiling focused on the regional specificity of the otocyst.
2011-05-23 | GSE19618 | GEO
Project description:Gene expression was analyzed in endolymphatic sacs of two groups of mice: Slc26a4Δ/Δ and Slc26a4Δ/+ mice. Slc26a4Δ/Δ mice fail to develop hearing and are a model for Enlarged Vestibular Aqueduct and Pendred Syndrome, two forms of human deafness that are associated with mutations of SLC26A4. Slc26a4Δ/+ mice develop normal hearing and served a controls. Gene expression was performed at embryonic day (E) 13.5, E14.5, E16.5 and E17.5, which are pathobiologically relevant time points that mark growth and enlargement of the entire inner ear including the cochlea and the vestibular aqueduct. Affymetrix microarrays were used to analyze gene expression and developmental changes in gene expression in Slc26a4Δ/Δ and Slc26a4Δ/+ mice with the goal to identify genes that are in a functional relationship with Slc26a4, the gene that codes for pendrin.
2017-09-22 | GSE90092 | GEO