scholarly journals A Critical E-box in Barhl1 3′ Enhancer Is Essential for Auditory Hair Cell Differentiation

Cells ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 458 ◽  
Author(s):  
Kun Hou ◽  
Hui Jiang ◽  
Md. Rezaul Karim ◽  
Chao Zhong ◽  
Zhouwen Xu ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Hair Cell ◽  
Hair Cells ◽  
Embryonic Stem ◽  
Cell Development ◽  
Homologous Gene ◽  
Auditory Hair Cells ◽  
E Box ◽  
Hair Cell Differentiation

Barhl1, a mouse homologous gene of Drosophila BarH class homeobox genes, is highly expressed within the inner ear and crucial for the long-term maintenance of auditory hair cells that mediate hearing and balance, yet little is known about the molecular events underlying Barhl1 regulation and function in hair cells. In this study, through data mining and in vitro report assay, we firstly identified Barhl1 as a direct target gene of Atoh1 and one E-box (E3) in Barhl1 3’ enhancer is crucial for Atoh1-mediated Barhl1 activation. Then we generated a mouse embryonic stem cell (mESC) line carrying disruptions on this E3 site E-box (CAGCTG) using CRISPR/Cas9 technology and this E3 mutated mESC line is further subjected to an efficient stepwise hair cell differentiation strategy in vitro. Disruptions on this E3 site caused dramatic loss of Barhl1 expression and significantly reduced the number of induced hair cell-like cells, while no affections on the differentiation toward early primitive ectoderm-like cells and otic progenitors. Finally, through RNA-seq profiling and gene ontology (GO) enrichment analysis, we found that this E3 box was indispensable for Barhl1 expression to maintain hair cell development and normal functions. We also compared the transcriptional profiles of induced cells from CDS mutated and E3 mutated mESCs, respectively, and got very consistent results except the Barhl1 transcript itself. These observations indicated that Atoh1-mediated Barhl1 expression could have important roles during auditory hair cell development. In brief, our findings delineate the detail molecular mechanism of Barhl1 expression regulation in auditory hair cell differentiation.

scholarly journals Promotion of In Vitro Hair Cell-like Cell Differentiation from Human Embryonic Stem Cells through the Regulation of Notch Signaling

Metabolites ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 873
Author(s):  
Fengjiao Chen ◽  
Ying Yang ◽  
Jianling Chen ◽  
Zihua Tang ◽  
Qian Peng ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cell Differentiation ◽  
Hair Cell ◽  
Hair Cells ◽  
Embryonic Stem ◽  
Temporal Expression ◽  
Supporting Cells ◽  
Temporal Expression Pattern ◽  
Notch Ligands

The Notch signaling pathway plays an important role in otic neurogenesis by regulating the differentiation of inner ear hair cells and supporting cells. Notch-regulated differentiation is required for the regeneration of hair cells in the inner ear. The temporal expression pattern of Notch ligands and receptors during in vitro hair cell-like cell differentiation from human embryonic stem cells (hESCs) was detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Subsequently, pAJ-U6-shRNA-CMV-Puro/GFP recombinant lentiviral vectors encoding short hairpin RNAs were used to silence JAG-1, JAG-2, and DLL-1, according to the temporal expression pattern of Notch ligands. Then, the effect of each ligand on the in vitro differentiation of hair cells was examined by RT-PCR, immunofluorescence, and scanning electron microscopy (SEM). The results showed that the individual deletion of JAG-2 or DLL-1 had no significant effect on the differentiation of hair cell-like cells. However, the simultaneous inhibition of both DLL-1 and JAG-2 increased the number of hair cell-like cells and decreased the number of supporting cells. JAG-2 and DLL-1 may have a synergistic role in in vitro hair cell differentiation.

Hes1 is a negative regulator of inner ear hair cell differentiation

Development ◽  
2000 ◽  
Vol 127 (21) ◽  
pp. 4551-4560 ◽  
Author(s):  
J.L. Zheng ◽  
J. Shou ◽  
F. Guillemot ◽  
R. Kageyama ◽  
W.Q. Gao
Keyword(s):  
Cell Differentiation ◽  
Hair Cell ◽  
Inner Ear ◽  
Cell Fate ◽  
Hair Cells ◽  
Outer Hair Cells ◽  
Negative Regulator ◽  
Pcr Analysis ◽  
Loss Of Function ◽  
Hair Cell Differentiation

Hair cell fate determination in the inner ear has been shown to be controlled by specific genes. Recent loss-of-function and gain-of-function experiments have demonstrated that Math1, a mouse homolog of the Drosophila gene atonal, is essential for the production of hair cells. To identify genes that may interact with Math1 and inhibit hair cell differentiation, we have focused on Hes1, a mammalian hairy and enhancer of split homolog, which is a negative regulator of neurogenesis. We report here that targeted deletion of Hes1 leads to formation of supernumerary hair cells in the cochlea and utricle of the inner ear. RT-PCR analysis shows that Hes1 is expressed in inner ear during hair cell differentiation and its expression is maintained in adulthood. In situ hybridization with late embryonic inner ear tissue reveals that Hes1 is expressed in supporting cells, but not hair cells, of the vestibular sensory epithelium. In the cochlea, Hes1 is selectively expressed in the greater epithelial ridge and lesser epithelial ridge regions which are adjacent to inner and outer hair cells. Co-transfection experiments in postnatal rat explant cultures show that overexpression of Hes1 prevents hair cell differentiation induced by Math1. Therefore Hes1 can negatively regulate hair cell differentiation by antagonizing Math1. These results suggest that a balance between Math1 and negative regulators such as Hes1 is crucial for the production of an appropriate number of inner ear hair cells.

scholarly journals A counter gradient of Activin A and follistatin instructs the timing of hair cell differentiation in the murine cochlea

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Meenakshi Prajapati-DiNubila ◽  
Ana Benito-Gonzalez ◽  
Erin Jennifer Golden ◽  
Shuran Zhang ◽  
Angelika Doetzlhofer
Keyword(s):  
Cell Differentiation ◽  
Hair Cell ◽  
Hair Cells ◽  
Activin A ◽  
Sensory Epithelium ◽  
Outer Hair Cells ◽  
Longitudinal Gradient ◽  
Hair Cell Differentiation ◽  
Local Gradient ◽  
Molecular Signals

The mammalian auditory sensory epithelium has one of the most stereotyped cellular patterns known in vertebrates. Mechano-sensory hair cells are arranged in precise rows, with one row of inner and three rows of outer hair cells spanning the length of the spiral-shaped sensory epithelium. Aiding such precise cellular patterning, differentiation of the auditory sensory epithelium is precisely timed and follows a steep longitudinal gradient. The molecular signals that promote auditory sensory differentiation and instruct its graded pattern are largely unknown. Here, we identify Activin A and its antagonist follistatin as key regulators of hair cell differentiation and show, using mouse genetic approaches, that a local gradient of Activin A signaling within the auditory sensory epithelium times the longitudinal gradient of hair cell differentiation. Furthermore, we provide evidence that Activin-type signaling regulates a radial gradient of terminal mitosis within the auditory sensory epithelium, which constitutes a novel mechanism for limiting the number of inner hair cells being produced.

Hair cell development in vivo and in vitro: Analysis by using a monoclonal antibody specific to hair cells in the chick inner ear

2002 ◽  
Vol 445 (2) ◽  
pp. 176-198
Author(s):  
Kenji Kondo ◽  
Hiroshi Sagara ◽  
Kazushige Hirosawa ◽  
Kimitaka Kaga ◽  
Satsuki Matsushima ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Hair Cell ◽  
Inner Ear ◽  
Hair Cells ◽  
Cell Development ◽  
Vitro Analysis ◽  
In Vitro Analysis

Notch signaling regulates the pattern of auditory hair cell differentiation in mammals

Development ◽  
2000 ◽  
Vol 127 (15) ◽  
pp. 3373-3383 ◽  
Author(s):  
A. Zine ◽  
T.R. Van De Water ◽  
F. de Ribaupierre
Keyword(s):  
Cell Differentiation ◽  
Hair Cell ◽  
Notch Signaling ◽  
Cell Fate ◽  
Hair Cells ◽  
Expression Patterns ◽  
Sensory Epithelium ◽  
Supporting Cells ◽  
Hair Cell Differentiation ◽  
Notch1 Signaling Pathway

The development of the mammalian cochlea is an example of patterning in the peripheral nervous system. Sensory hair cells and supporting cells in the cochlea differentiate via regional and cell fate specification. The Notch signaling components shows both distinct and overlapping expression patterns of Notch1 receptor and its ligands Jagged1 (Jag1) and Jagged2 (Jag2) in the developing auditory epithelium of the rat. On embryonic day 16 (E16), many precursor cells within the Kolliker's organ immunostained for the presence of both Notch1 and Jag1, while the area of hair cell precursors did not express either Notch1 and Jag1. During initial events of hair cell differentiation between E18 and birth, Notch1 and Jag1 expression predominated in supporting cells and Jag2 in nascent hair cells. Early after birth, Jag2 expression decreased in hair cells while the pattern of Notch1 expression now included both supporting cells and hair cells. We show that the normal pattern of hair cell differentiation is disrupted by alteration of Notch signaling. A decrease of either Notch1 or Jag1 expression by antisense oligonucleotides in cultures of the developing sensory epithelium resulted in an increase in the number of hair cells. Our data suggest that the Notch1 signaling pathway is involved in a complex interplay between the consequences of different ligand-Notch1 combinations during cochlear morphogenesis and the phases of hair cell differentiation.

scholarly journals The deltaA gene of zebrafish mediates lateral inhibition of hair cells in the inner ear and is regulated by pax2.1

Development ◽  
1999 ◽  
Vol 126 (24) ◽  
pp. 5669-5678 ◽  
Author(s):  
B.B. Riley ◽  
M. Chiang ◽  
L. Farmer ◽  
R. Heck
Keyword(s):  
Cell Differentiation ◽  
Hair Cell ◽  
Inner Ear ◽  
Cell Fate ◽  
Lateral Inhibition ◽  
Hair Cells ◽  
Fold Increase ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Hair Cell Differentiation

Recent studies of inner ear development suggest that hair cells and support cells arise within a common equivalence group by cell-cell interactions mediated by Delta and Notch proteins. We have extended these studies by analyzing the effects of a mutant allele of the zebrafish deltaA gene, deltaA(dx2), which encodes a dominant-negative protein. deltaA(dx2/dx2)homozygous mutants develop with a 5- to 6-fold excess of hair cells and a severe deficiency of support cells. In addition, deltaA(dx2/dx2) mutants show an increased number of cells expressing pax2.1 in regions where hair cells are normally produced. Immunohistological analysis of wild-type and deltaA(dx2/dx2) mutant embryos confirmed that pax2.1 is expressed during the initial stages of hair cell differentiation and is later maintained at high levels in mature hair cells. In contrast, pax2.1 is not expressed in support cells. To address the function of pax2.1, we analyzed hair cell differentiation in no isthmus mutant embryos, which are deficient for pax2.1 function. no isthmus mutant embryos develop with approximately twice the normal number of hair cells. This neurogenic defect correlates with reduced levels of expression of deltaA and deltaD in the hair cells in no isthmus mutants. Analysis of deltaA(dx2/dx2); no isthmus double mutants showed that no isthmus suppresses the deltaA(dx2) phenotype, probably by reducing levels of the dominant-negative mutant protein. This interpretation was supported by analysis of T(msxB)(b220), a deletion that removes the deltaA locus. Reducing the dose of deltaA(dx2) by generating deltaA(dx2)/T(msxB)(b220)trans-heterozygotes weakens the neurogenic effects of deltaA(dx2), whereas T(msxB)(b220) enhances the neurogenic defects of no isthmus. mind bomb, another strong neurogenic mutation that may disrupt reception of Delta signals, causes a 10-fold increase in hair cell production and is epistatic to both no isthmus and deltaA(dx2). These data indicate that deltaA expressed by hair cells normally prevents adjacent cells from adopting the same cell fate, and that pax2.1 is required for normal levels of Delta-mediated lateral inhibition.

scholarly journals GFI1 functions to repress neuronal gene expression in the developing inner ear hair cells

Development ◽  
2020 ◽  
Vol 147 (17) ◽  
pp. dev186015 ◽  
Author(s):  
Maggie S. Matern ◽  
Beatrice Milon ◽  
Erika L. Lipford ◽  
Mark McMurray ◽  
Yoko Ogawa ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Hair Cell ◽  
Inner Ear ◽  
Hair Cells ◽  
Neuronal Development ◽  
Cell Development ◽  
Vestibular Hair Cells ◽  
Normal Functional ◽  
Neuronal Genes ◽  
Hair Cell Differentiation

ABSTRACTDespite the known importance of the transcription factors ATOH1, POU4F3 and GFI1 in hair cell development and regeneration, their downstream transcriptional cascades in the inner ear remain largely unknown. Here, we have used Gfi1cre;RiboTag mice to evaluate changes to the hair cell translatome in the absence of GFI1. We identify a systematic downregulation of hair cell differentiation genes, concomitant with robust upregulation of neuronal genes in the GFI1-deficient hair cells. This includes increased expression of neuronal-associated transcription factors (e.g. Pou4f1) as well as transcription factors that serve dual roles in hair cell and neuronal development (e.g. Neurod1, Atoh1 and Insm1). We further show that the upregulated genes are consistent with the NEUROD1 regulon and are normally expressed in hair cells prior to GFI1 onset. Additionally, minimal overlap of differentially expressed genes in auditory and vestibular hair cells suggests that GFI1 serves different roles in these systems. From these data, we propose a dual mechanism for GFI1 in promoting hair cell development, consisting of repression of neuronal-associated genes as well as activation of hair cell-specific genes required for normal functional maturation.

Promotion of in Vitro Hair Cell-like Cell Differentiation from Human Embryonic Stem Cells through the Regulation of Notch Signaling

2021 ◽  
Author(s):  
Fengjiao Chen ◽  
Ying Yang ◽  
Jianling Chen ◽  
Zihua Tang ◽  
Qian Peng ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Hair Cell ◽  
Notch Signaling ◽  
Hair Cells ◽  
Embryonic Stem ◽  
In Vitro Differentiation ◽  
Supporting Cells ◽  
Notch Ligands

Abstract Background Notch signaling mediates the committed induced differentiation of ear sensory cells and promotes the formation of a precise arrangement of mosaics between hair cells and supporting cells. Embryonic stem cells (ESCs) are pluripotent stem cells which have the potential to differentiate into cell lines through three germ layers. Therefore, it is necessary to study the effects of regulating Notch receptors and ligand expression on the in vitro differentiation equilibrium of hair cells and supporting cells from ESCs.Methods and Results The temporal ex-pression pattern of Notch ligands and receptors during in vitro hair cell-like cell differentia-tion from human embryonic stem cells (hESCs) was detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Subsequently, pAJ-U6-shRNA-CMV-Puro/GFP recombinant lentiviral vectors, encoding short hairpin RNAs, were used to silence JAG-1, JAG-2, and DLL-1, according to the temporal expression pattern of Notch ligands. Then the effect of each ligand on the in vitro differentiation of hair cells was examined by RT-PCR, immunofluorescence, and scanning electron microscopy (SEM).Conclusions Results showed that JAG-1 played an important role in regulating hESC differentiation to otic progenitors. The individual deletion of JAG-2 or DLL-1 had no significant effect on the differentiation of hair cell-like cells. Although the simultaneous inhibition of both DLL-1 and JAG-2 could increase the number of hair cell-like cells, it decreased the number of supporting cells.

scholarly journals Hair necessities: Hair cell differentiation and regeneration

2002 ◽  
Vol 24 (6) ◽  
pp. 9-11
Author(s):  
Matthew Holley
Keyword(s):  
Cell Differentiation ◽  
Hair Cell ◽  
Hair Cells ◽  
Organ Of Corti ◽  
Structural Diversity ◽  
Sensory Epithelium ◽  
Animal Kingdom ◽  
Hair Cell Differentiation ◽  
Human Hearing ◽  
Mechanosensory Hair Cells

Human hearing is governed by approximately 15 500 mechanosensory hair cells in each ear. These cells are located within the organ of Corti, the elongated auditory sensory epithelium that is stretched inside the coiled cochleae of the inner ear. Despite the structural diversity between the organs of hearing throughout the animal kingdom, hair cells are instantly recognizable. Their shapes and sizes vary considerably, but their apices carry a characteristic bundle of actin-filled stereocilia, or hairs, whose tips are connected by stretch-sensitive ‘tip-links’1. However, unlike most other animals, mammals do not regenerate lost hair cells2, consequently most forms of deafness are irreversible.

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