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Singh N, Kaushik R, Prakash A, Singh Saini S, Garg S, Adhikary A, Ladher RK. Mosaic Atoh1 deletion in the chick auditory epithelium reveals a homeostatic mechanism to restore hair cell number. Dev Biol 2024; 516:35-46. [PMID: 39074652 DOI: 10.1016/j.ydbio.2024.07.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2024] [Revised: 07/16/2024] [Accepted: 07/26/2024] [Indexed: 07/31/2024]
Abstract
The mechanosensory hair cell of the vertebrate inner ear responds to the mechanical deflections that result from hearing or change in the acceleration due to gravity, to allow us to perceive and interpret sounds, maintain balance and spatial orientation. In mammals, ototoxic compounds, disease, and acoustic trauma can result in damage and extrusion of hair cells, without replacement, resulting in hearing loss. In contrast, non-mammalian vertebrates can regenerate sensory hair cells. Upon damage, hair cells are extruded and an associated cell type, the supporting cell is transformed into a hair cell. The mechanisms that can trigger regeneration are not known. Using mosaic deletion of the hair cell master gene, Atoh1, in the embryonic avian inner ear, we find that despite hair cells depletion at E9, by E12, hair cell number is restored in sensory epithelium. Our study suggests a homeostatic mechanism can restores hair cell number in the basilar papilla, that is activated when juxtracrine signalling is disrupted. Restoration of hair cell numbers during development may mirror regenerative processes, and our work provides insights into the mechanisms that trigger regeneration.
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Affiliation(s)
- Nishant Singh
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, GKVK PO, Bellary Road, Bangalore, 560065, India; The University of Trans-Disciplinary Health Sciences and Technology, Yelahanka, Bangalore, 560064, India
| | - Raman Kaushik
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, GKVK PO, Bellary Road, Bangalore, 560065, India
| | - Anubhav Prakash
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, GKVK PO, Bellary Road, Bangalore, 560065, India; Ashoka University, Sonipat, Haryana, 131029, India
| | - Surjit Singh Saini
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, GKVK PO, Bellary Road, Bangalore, 560065, India
| | - Sonal Garg
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, GKVK PO, Bellary Road, Bangalore, 560065, India
| | - Adrija Adhikary
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, GKVK PO, Bellary Road, Bangalore, 560065, India
| | - Raj K Ladher
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, GKVK PO, Bellary Road, Bangalore, 560065, India.
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2
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Cai W, Huang Z, Sun B, Lu L, Ding X, Tao F. The differentiation of Lgr5+ progenitor cells on nanostructures of self-assembled silica beads. PLoS One 2024; 19:e0304809. [PMID: 38995923 PMCID: PMC11244819 DOI: 10.1371/journal.pone.0304809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 05/19/2024] [Indexed: 07/14/2024] Open
Abstract
Supporting cells(SCs) have been demonstrated to be a reliable source for regenerating hair cells(HCs). Previous research has reported that Lgr5+ SCs can regenerate HCs both in vitro and in vivo. However, there is limited knowledge about the impact of the material on Lgr5+ cells. In this study, Lgr5+ cells were isolated from neonatal Lgr5-EGFP-CreERT2 transgenic mice by flow cytometry and then plated on self-assembled silica beads (SB). Lgr5+ cell differentiation was observed by immunofluorescence. We found that in the direct differentiation assay, the SB group generated more hair cells than the control group(*p < 0.05). Especially in the SB group, Lgr5+ progenitors generated significantly more Myo7a+ HCs outside of the colony than in the control group(**p < 0.01). In the sphere differentiation assay, we found that the diameter of spheres in the SB group was significantly larger compared to those of the control group(**p < 0.01). However, the difference in the ratio of myo7a+ cell counts was not obvious(P>0.05). The experiment proved that the self-assembled silica beads could promote the differentiation of Lgr5+ progenitors in vitro. Our findings implicate that nanostructures of self-assembled silica beads can be used as vectors for stem cell research in the inner ear.
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Affiliation(s)
- Wenjun Cai
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhong Da Hospital, Southeast University, Nanjing, China
| | - Zhichun Huang
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhong Da Hospital, Southeast University, Nanjing, China
| | - Baobin Sun
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhong Da Hospital, Southeast University, Nanjing, China
| | - Ling Lu
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhong Da Hospital, Southeast University, Nanjing, China
| | - Xiaoqiong Ding
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhong Da Hospital, Southeast University, Nanjing, China
| | - Feng Tao
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhong Da Hospital, Southeast University, Nanjing, China
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3
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Choi SW, Abitbol JM, Cheng AG. Hair Cell Regeneration: From Animals to Humans. Clin Exp Otorhinolaryngol 2024; 17:1-14. [PMID: 38271988 PMCID: PMC10933805 DOI: 10.21053/ceo.2023.01382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 01/07/2024] [Accepted: 01/17/2024] [Indexed: 01/27/2024] Open
Abstract
Cochlear hair cells convert sound into electrical signals that are relayed via the spiral ganglion neurons to the central auditory pathway. Hair cells are vulnerable to damage caused by excessive noise, aging, and ototoxic agents. Non-mammals can regenerate lost hair cells by mitotic regeneration and direct transdifferentiation of surrounding supporting cells. However, in mature mammals, damaged hair cells are not replaced, resulting in permanent hearing loss. Recent studies have uncovered mechanisms by which sensory organs in non-mammals and the neonatal mammalian cochlea regenerate hair cells, and outlined possible mechanisms why this ability declines rapidly with age in mammals. Here, we review similarities and differences between avian, zebrafish, and mammalian hair cell regeneration. Moreover, we discuss advances and limitations of hair cell regeneration in the mature cochlea and their potential applications to human hearing loss.
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Affiliation(s)
- Sung-Won Choi
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA
- Department of Otorhinolaryngology-Head and Neck Surgery and Biomedical Research Institute, Pusan National University Hospital, Busan, Korea
- Department of Otorhinolaryngology-Head and Neck Surgery, Pusan National University School of Medicine, Busan, Korea
| | - Julia M. Abitbol
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Alan G. Cheng
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA
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4
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Li X, Morgan C, Nadar‐Ponniah PT, Kolanus W, Doetzlhofer A. TRIM71 reactivation enhances the mitotic and hair cell-forming potential of cochlear supporting cells. EMBO Rep 2023; 24:e56562. [PMID: 37492931 PMCID: PMC10481673 DOI: 10.15252/embr.202256562] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 06/27/2023] [Accepted: 07/04/2023] [Indexed: 07/27/2023] Open
Abstract
Cochlear hair cell loss is a leading cause of deafness in humans. Neighboring supporting cells have some capacity to regenerate hair cells. However, their regenerative potential sharply declines as supporting cells undergo maturation (postnatal day 5 in mice). We recently reported that reactivation of the RNA-binding protein LIN28B restores the hair cell-regenerative potential of P5 cochlear supporting cells. Here, we identify the LIN28B target Trim71 as a novel and equally potent enhancer of supporting cell plasticity. TRIM71 is a critical regulator of stem cell behavior and cell reprogramming; however, its role in cell regeneration is poorly understood. Employing an organoid-based assay, we show that TRIM71 re-expression increases the mitotic and hair cell-forming potential of P5 cochlear supporting cells by facilitating their de-differentiation into progenitor-like cells. Our mechanistic work indicates that TRIM71's RNA-binding activity is essential for such ability, and our transcriptomic analysis identifies gene modules that are linked to TRIM71 and LIN28B-mediated supporting cell reprogramming. Furthermore, our study uncovers that the TRIM71-LIN28B target Hmga2 is essential for supporting cell self-renewal and hair cell formation.
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Affiliation(s)
- Xiao‐Jun Li
- The Solomon H. Snyder Department of NeuroscienceJohns Hopkins University School of MedicineBaltimoreMDUSA
- Present address:
Frontier Institute of Science and TechnologyXi'an Jiaotong UniversityXi'an710054China
| | - Charles Morgan
- The Solomon H. Snyder Department of NeuroscienceJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Prathamesh T Nadar‐Ponniah
- The Solomon H. Snyder Department of NeuroscienceJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Waldemar Kolanus
- Molecular Immunology and Cell Biology, Life & Medical Sciences Institute (LIMES)University of BonnBonnGermany
| | - Angelika Doetzlhofer
- The Solomon H. Snyder Department of NeuroscienceJohns Hopkins University School of MedicineBaltimoreMDUSA
- Department of Otolaryngology and Center for Hearing and BalanceJohns Hopkins University School of MedicineBaltimoreMDUSA
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5
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Nguyen JD, Llamas J, Shi T, Crump JG, Groves AK, Segil N. DNA methylation in the mouse cochlea promotes maturation of supporting cells and contributes to the failure of hair cell regeneration. Proc Natl Acad Sci U S A 2023; 120:e2300839120. [PMID: 37549271 PMCID: PMC10438394 DOI: 10.1073/pnas.2300839120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 07/11/2023] [Indexed: 08/09/2023] Open
Abstract
Mammalian hair cells do not functionally regenerate in adulthood but can regenerate at embryonic and neonatal stages in mice by direct transdifferentiation of neighboring supporting cells into new hair cells. Previous work showed loss of transdifferentiation potential of supporting cells is in part due to H3K4me1 enhancer decommissioning of the hair cell gene regulatory network during the first postnatal week. However, inhibiting this decommissioning only partially preserves transdifferentiation potential. Therefore, we explored other repressive epigenetic modifications that may be responsible for this loss of plasticity. We find supporting cells progressively accumulate DNA methylation at promoters of developmentally regulated hair cell genes. Specifically, DNA methylation overlaps with binding sites of Atoh1, a key transcription factor for hair cell fate. We further show that DNA hypermethylation replaces H3K27me3-mediated repression of hair cell genes in mature supporting cells, and is accompanied by progressive loss of chromatin accessibility, suggestive of facultative heterochromatin formation. Another subset of hair cell loci is hypermethylated in supporting cells, but not in hair cells. Ten-eleven translocation (TET) enzyme-mediated demethylation of these hypermethylated sites is necessary for neonatal supporting cells to transdifferentiate into hair cells. We also observe changes in chromatin accessibility of supporting cell subtypes at the single-cell level with increasing age: Gene programs promoting sensory epithelium development loses chromatin accessibility, in favor of gene programs that promote physiological maturation and function of the cochlea. We also find chromatin accessibility is partially recovered in a chronically deafened mouse model, which holds promise for future translational efforts in hearing restoration.
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Affiliation(s)
- John D. Nguyen
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of the University of Southern California, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Biology at the University of Southern California, Los Angeles, CA90033
| | - Juan Llamas
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of the University of Southern California, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Biology at the University of Southern California, Los Angeles, CA90033
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA90033
| | - Tuo Shi
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of the University of Southern California, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Biology at the University of Southern California, Los Angeles, CA90033
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA90033
| | - J. Gage Crump
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of the University of Southern California, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Biology at the University of Southern California, Los Angeles, CA90033
| | - Andrew K. Groves
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX77030
- Department of Neuroscience, Baylor College of Medicine, Houston, TX77030
| | - Neil Segil
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of the University of Southern California, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Biology at the University of Southern California, Los Angeles, CA90033
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA90033
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6
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Smith-Cortinez N, Tan AK, Stokroos RJ, Versnel H, Straatman LV. Regeneration of Hair Cells from Endogenous Otic Progenitors in the Adult Mammalian Cochlea: Understanding Its Origins and Future Directions. Int J Mol Sci 2023; 24:ijms24097840. [PMID: 37175547 PMCID: PMC10177935 DOI: 10.3390/ijms24097840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/20/2023] [Accepted: 04/21/2023] [Indexed: 05/15/2023] Open
Abstract
Sensorineural hearing loss is caused by damage to sensory hair cells and/or spiral ganglion neurons. In non-mammalian species, hair cell regeneration after damage is observed, even in adulthood. Although the neonatal mammalian cochlea carries regenerative potential, the adult cochlea cannot regenerate lost hair cells. The survival of supporting cells with regenerative potential after cochlear trauma in adults is promising for promoting hair cell regeneration through therapeutic approaches. Targeting these cells by manipulating key signaling pathways that control mammalian cochlear development and non-mammalian hair cell regeneration could lead to regeneration of hair cells in the mammalian cochlea. This review discusses the pathways involved in the development of the cochlea and the impact that trauma has on the regenerative capacity of the endogenous progenitor cells. Furthermore, it discusses the effects of manipulating key signaling pathways targeting supporting cells with progenitor potential to promote hair cell regeneration and translates these findings to the human situation. To improve hearing recovery after hearing loss in adults, we propose a combined approach targeting (1) the endogenous progenitor cells by manipulating signaling pathways (Wnt, Notch, Shh, FGF and BMP/TGFβ signaling pathways), (2) by manipulating epigenetic control, and (3) by applying neurotrophic treatments to promote reinnervation.
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Affiliation(s)
- Natalia Smith-Cortinez
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- UMC Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
| | - A Katherine Tan
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- UMC Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
| | - Robert J Stokroos
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- UMC Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
| | - Huib Versnel
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- UMC Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
| | - Louise V Straatman
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- UMC Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
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7
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Li XJ, Morgan C, Nadar-Ponniah PT, Kolanus W, Doetzlhofer A. Reactivation of the progenitor gene Trim71 enhances the mitotic and hair cell-forming potential of cochlear supporting cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.12.523802. [PMID: 36711735 PMCID: PMC9882147 DOI: 10.1101/2023.01.12.523802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Cochlear hair cell loss is a leading cause of deafness in humans. Neighboring supporting cells have some capacity to regenerate hair cells. However, their regenerative potential sharply declines as supporting cells undergo maturation (postnatal day 5 in mice). We recently reported that reactivation of the RNA-binding protein LIN28B restores the hair cell-regenerative potential of P5 cochlear supporting cells. Here, we identify the LIN28B target Trim71 as a novel and equally potent enhancer of supporting cell plasticity. TRIM71 is a critical regulator of stem cell behavior and cell reprogramming, however, its role in cell regeneration is poorly understood. Employing an organoid-based assay, we show that TRIM71 reactivation increases the mitotic and hair cell-forming potential of P5 cochlear supporting cells by facilitating their de-differentiation into progenitor-like cells. Our mechanistic work indicates that TRIM71’s RNA-binding activity is essential for such ability, and our transcriptomic analysis identifies gene modules that are linked to TRIM71 and LIN28B-mediated supporting cell reprogramming. Furthermore, our study uncovers that the TRIM71-LIN28B target Hmga2 is essential for supporting cell self-renewal and hair cell formation.
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8
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Deletion of Notch1 during Cochlear Maturation Leads to Rapid Supporting Cell Death and Profound Deafness. J Neurosci 2023; 43:199-210. [PMID: 36418183 PMCID: PMC9838715 DOI: 10.1523/jneurosci.1090-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 09/14/2022] [Accepted: 11/08/2022] [Indexed: 11/25/2022] Open
Abstract
The sensory region of the mammalian hearing organ contains two main cell types-hair cells and supporting cells. During development, Notch signaling plays an important role in whether a cell becomes either a hair cell or supporting cell by mediating lateral inhibition. However, once the cell fate decisions have been determined, little is understood about the role Notch plays in cochlear maturation. Here, we report that deletion of Notch1 from the early postnatal mouse cochlea in both male and female animals resulted in profound deafness at 6 weeks of age. Histologic analyses at 6 weeks revealed significant hair cell and supporting cell loss throughout the Notch1-deficient cochlea. Early analyses revealed a reduction in supporting cells in the outer hair cell region between postnatal day (P) 2 and P6, without a comparable increase in outer hair cell number, suggesting a mechanism other than lateral inhibition. Consistent with this, we found apoptotic cells in the outer supporting cell region of the cochlea at P1 and P2, indicating that Notch1 is required for outer supporting cell survival during early cochlear maturation. Interestingly, inner supporting cell types were not lost after Notch1 deletion. Surprisingly, we do not detect outer hair cell loss in Notch1 mutants until after the onset of hearing, around P14, suggesting that hair cell loss is caused by loss of the supporting cells. Together, these results demonstrate that Notch1 is required for supporting cell survival during early maturation and that loss of these cells causes later loss of the hair cells and cochlear dysfunction.SIGNIFICANCE STATEMENT During development, Notch signaling has been shown to be critical in regulating the cell fate choices between hair cells and supporting cells. However, little is known about how Notch functions after those cell fate choices are made. Here, we examine the role of Notch1 in the maturing cochlea. We demonstrate that deletion of Notch1 results in profound deafness by 6 weeks of age. Histologic analyses revealed rapid supporting cell death shortly after Notch1 deletion, followed by eventual loss of the hair cells. These results reveal an unexpected role for Notch in supporting cell survival during cochlear maturation.
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9
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Piekna-Przybylska D, Na D, Zhang J, Baker C, Ashton JM, White PM. Single cell RNA sequencing analysis of mouse cochlear supporting cell transcriptomes with activated ERBB2 receptor indicates a cell-specific response that promotes CD44 activation. Front Cell Neurosci 2023; 16:1096872. [PMID: 36687526 PMCID: PMC9853549 DOI: 10.3389/fncel.2022.1096872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 12/12/2022] [Indexed: 01/07/2023] Open
Abstract
Hearing loss caused by the death of cochlear hair cells (HCs) might be restored through regeneration from supporting cells (SCs) via dedifferentiation and proliferation, as observed in birds. In a previous report, ERBB2 activation in a subset of cochlear SCs promoted widespread down-regulation of SOX2 in neighboring cells, proliferation, and the differentiation of HC-like cells. Here we analyze single cell transcriptomes from neonatal mouse cochlear SCs with activated ERBB2, with the goal of identifying potential secreted effectors. ERBB2 induction in vivo generated a new population of cells with de novo expression of a gene network. Called small integrin-binding ligand n-linked glycoproteins (SIBLINGs), these ligands and their regulators can alter NOTCH signaling and promote cell survival, proliferation, and differentiation in other systems. We validated mRNA expression of network members, and then extended our analysis to older stages. ERBB2 signaling in young adult SCs also promoted protein expression of gene network members. Furthermore, we found proliferating cochlear cell aggregates in the organ of Corti. Our results suggest that ectopic activation of ERBB2 signaling in cochlear SCs can alter the microenvironment, promoting proliferation and cell rearrangements. Together these results suggest a novel mechanism for inducing stem cell-like activity in the adult mammalian cochlea.
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Affiliation(s)
- Dorota Piekna-Przybylska
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Daxiang Na
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Jingyuan Zhang
- Department of Biology, University of Rochester, Rochester, NY, United States
| | - Cameron Baker
- Genomic Research Center, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - John M. Ashton
- Genomic Research Center, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Patricia M. White
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
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10
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Iyer AA, Hosamani I, Nguyen JD, Cai T, Singh S, McGovern MM, Beyer L, Zhang H, Jen HI, Yousaf R, Birol O, Sun JJ, Ray RS, Raphael Y, Segil N, Groves AK. Cellular reprogramming with ATOH1, GFI1, and POU4F3 implicate epigenetic changes and cell-cell signaling as obstacles to hair cell regeneration in mature mammals. eLife 2022; 11:e79712. [PMID: 36445327 PMCID: PMC9708077 DOI: 10.7554/elife.79712] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 11/16/2022] [Indexed: 11/30/2022] Open
Abstract
Reprogramming of the cochlea with hair-cell-specific transcription factors such as ATOH1 has been proposed as a potential therapeutic strategy for hearing loss. ATOH1 expression in the developing cochlea can efficiently induce hair cell regeneration but the efficiency of hair cell reprogramming declines rapidly as the cochlea matures. We developed Cre-inducible mice to compare hair cell reprogramming with ATOH1 alone or in combination with two other hair cell transcription factors, GFI1 and POU4F3. In newborn mice, all transcription factor combinations tested produced large numbers of cells with the morphology of hair cells and rudimentary mechanotransduction properties. However, 1 week later, only a combination of ATOH1, GFI1 and POU4F3 could reprogram non-sensory cells of the cochlea to a hair cell fate, and these new cells were less mature than cells generated by reprogramming 1 week earlier. We used scRNA-seq and combined scRNA-seq and ATAC-seq to suggest at least two impediments to hair cell reprogramming in older animals. First, hair cell gene loci become less epigenetically accessible in non-sensory cells of the cochlea with increasing age. Second, signaling from hair cells to supporting cells, including Notch signaling, can prevent reprogramming of many supporting cells to hair cells, even with three hair cell transcription factors. Our results shed light on the molecular barriers that must be overcome to promote hair cell regeneration in the adult cochlea.
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Affiliation(s)
- Amrita A Iyer
- Department of Molecular & Human Genetics, Baylor College of MedicineHoustonUnited States
| | - Ishwar Hosamani
- Department of Molecular & Human Genetics, Baylor College of MedicineHoustonUnited States
| | - John D Nguyen
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of the University of Southern California, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Biology at USCLos AngelesUnited States
| | - Tiantian Cai
- Program in Developmental Biology, Baylor College of MedicineHoustonUnited States
| | - Sunita Singh
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
| | - Melissa M McGovern
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
| | - Lisa Beyer
- Department of Otolaryngology-Head and Neck Surgery, University of MichiganAnn ArborUnited States
| | - Hongyuan Zhang
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
| | - Hsin-I Jen
- Program in Developmental Biology, Baylor College of MedicineHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
| | - Rizwan Yousaf
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
| | - Onur Birol
- Program in Developmental Biology, Baylor College of MedicineHoustonUnited States
| | - Jenny J Sun
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
| | - Russell S Ray
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
| | - Yehoash Raphael
- Department of Otolaryngology-Head and Neck Surgery, University of MichiganAnn ArborUnited States
| | - Neil Segil
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of the University of Southern California, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Biology at USCLos AngelesUnited States
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern CaliforniaLos AngelesUnited States
| | - Andrew K Groves
- Department of Molecular & Human Genetics, Baylor College of MedicineHoustonUnited States
- Program in Developmental Biology, Baylor College of MedicineHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
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11
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Chen J, Gao D, Sun L, Yang J. Kölliker’s organ-supporting cells and cochlear auditory development. Front Mol Neurosci 2022; 15:1031989. [PMID: 36304996 PMCID: PMC9592740 DOI: 10.3389/fnmol.2022.1031989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 09/23/2022] [Indexed: 11/21/2022] Open
Abstract
The Kölliker’s organ is a transient cellular cluster structure in the development of the mammalian cochlea. It gradually degenerates from embryonic columnar cells to cuboidal cells in the internal sulcus at postnatal day 12 (P12)–P14, with the cochlea maturing when the degeneration of supporting cells in the Kölliker’s organ is complete, which is distinct from humans because it disappears at birth already. The supporting cells in the Kölliker’s organ play a key role during this critical period of auditory development. Spontaneous release of ATP induces an increase in intracellular Ca2+ levels in inner hair cells in a paracrine form via intercellular gap junction protein hemichannels. The Ca2+ further induces the release of the neurotransmitter glutamate from the synaptic vesicles of the inner hair cells, which subsequently excite afferent nerve fibers. In this way, the supporting cells in the Kölliker’s organ transmit temporal and spatial information relevant to cochlear development to the hair cells, promoting fine-tuned connections at the synapses in the auditory pathway, thus facilitating cochlear maturation and auditory acquisition. The Kölliker’s organ plays a crucial role in such a scenario. In this article, we review the morphological changes, biological functions, degeneration, possible trans-differentiation of cochlear hair cells, and potential molecular mechanisms of supporting cells in the Kölliker’s organ during the auditory development in mammals, as well as future research perspectives.
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Affiliation(s)
- Jianyong Chen
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Dekun Gao
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Lianhua Sun
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
- *Correspondence: Lianhua Sun Jun Yang
| | - Jun Yang
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
- *Correspondence: Lianhua Sun Jun Yang
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12
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Single-cell transcriptome analysis reveals three sequential phases of gene expression during zebrafish sensory hair cell regeneration. Dev Cell 2022; 57:799-819.e6. [PMID: 35316618 PMCID: PMC9188816 DOI: 10.1016/j.devcel.2022.03.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 11/19/2021] [Accepted: 02/28/2022] [Indexed: 12/20/2022]
Abstract
Loss of sensory hair cells (HCs) in the mammalian inner ear leads to permanent hearing and vestibular defects, whereas loss of HCs in zebrafish results in their regeneration. We used single-cell RNA sequencing (scRNA-seq) to characterize the transcriptional dynamics of HC regeneration in zebrafish at unprecedented spatiotemporal resolution. We uncovered three sequentially activated modules: first, an injury/inflammatory response and downregulation of progenitor cell maintenance genes within minutes after HC loss; second, the transient activation of regeneration-specific genes; and third, a robust re-activation of developmental gene programs, including HC specification, cell-cycle activation, ribosome biogenesis, and a metabolic switch to oxidative phosphorylation. The results are relevant not only for our understanding of HC regeneration and how we might be able to trigger it in mammals but also for regenerative processes in general. The data are searchable and publicly accessible via a web-based interface.
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13
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Li XJ, Morgan C, Goff LA, Doetzlhofer A. Follistatin promotes LIN28B-mediated supporting cell reprogramming and hair cell regeneration in the murine cochlea. SCIENCE ADVANCES 2022; 8:eabj7651. [PMID: 35148175 PMCID: PMC8836811 DOI: 10.1126/sciadv.abj7651] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 12/18/2021] [Indexed: 05/27/2023]
Abstract
Hair cell (HC) loss within the inner ear cochlea is a leading cause for deafness in humans. Before the onset of hearing, immature supporting cells (SCs) in neonatal mice have some limited capacity for HC regeneration. Here, we show that in organoid culture, transient activation of the progenitor-specific RNA binding protein LIN28B and Activin antagonist follistatin (FST) enhances regenerative competence of maturing/mature cochlear SCs by reprogramming them into progenitor-like cells. Transcriptome profiling and mechanistic studies reveal that LIN28B drives SC reprogramming, while FST is required to counterbalance hyperactivation of transforming growth factor-β-type signaling by LIN28B. Last, we show that LIN28B and FST coactivation enhances spontaneous cochlear HC regeneration in neonatal mice and that LIN28B may be part of an endogenous repair mechanism that primes SCs for HC regeneration. These findings indicate that SC dedifferentiation is critical for HC regeneration and identify LIN28B and FST as main regulators.
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Affiliation(s)
- Xiao-Jun Li
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Charles Morgan
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Loyal A. Goff
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Angelika Doetzlhofer
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Otolaryngology and Center for Hearing and Balance, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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14
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Chen Y, Qiang R, Zhang Y, Cao W, Wu L, Jiang P, Ai J, Ma X, Dong Y, Gao X, Li H, Lu L, Zhang S, Chai R. The Expression and Roles of the Super Elongation Complex in Mouse Cochlear Lgr5+ Progenitor Cells. Front Cell Neurosci 2021; 15:735723. [PMID: 34658793 PMCID: PMC8519586 DOI: 10.3389/fncel.2021.735723] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 09/14/2021] [Indexed: 12/04/2022] Open
Abstract
The super elongation complex (SEC) has been reported to play a key role in the proliferation and differentiation of mouse embryonic stem cells. However, the expression pattern and function of the SEC in the inner ear has not been investigated. Here, we studied the inner ear expression pattern of three key SEC components, AFF1, AFF4, and ELL3, and found that these three proteins are all expressed in both cochlear hair cells (HCs)and supporting cells (SCs). We also cultured Lgr5+ inner ear progenitors in vitro for sphere-forming assays and differentiation assays in the presence of the SEC inhibitor flavopiridol. We found that flavopiridol treatment decreased the proliferation ability of Lgr5+ progenitors, while the differentiation ability of Lgr5+ progenitors was not affected. Our results suggest that the SEC might play important roles in regulating inner ear progenitors and thus regulating HC regeneration. Therefore, it will be very meaningful to further investigate the detailed roles of the SEC signaling pathway in the inner ear in vivo in order to develop effective treatments for sensorineural hearing loss.
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Affiliation(s)
- Yin Chen
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - Ruiying Qiang
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Yuan Zhang
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Wei Cao
- Department of Otorhinolaryngology, Head and Neck Surgery, The Second Hospital of Anhui Medical University, Hefei, China
| | - Leilei Wu
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Pei Jiang
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Jingru Ai
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Xiangyu Ma
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Ying Dong
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Xia Gao
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - He Li
- Department of Otolaryngology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Ling Lu
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - Shasha Zhang
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
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15
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Hu Z, Singh A, Bojrab D, Sim N. Insights into the molecular mechanisms regulating mammalian hair cell regeneration. Curr Opin Otolaryngol Head Neck Surg 2021; 29:400-406. [PMID: 34374666 DOI: 10.1097/moo.0000000000000752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
PURPOSE OF REVIEW To give an overview of recent advances in mammalian auditory hair cell regeneration. RECENT FINDINGS Supporting cells act as progenitors to regenerate hair cells in the prehearing mammalian cochlea but not in the mature cochlea. To overcome this developmental obstacle, manipulation of multiple genes and intracellular pathways has been investigated, which has obtained promising data. This review focuses on recent advances in auditory hair cell regeneration, including synergic gene regulation associated with Atoh1 and Notch signaling, epigenetics, and functional recovery of regenerated hair cells. Co-manipulation of genes critical for hair cell development and cell cycle re-entry, including Atoh1, Isl1, Pou4f3, Gata3, Gfi1, P27kip1, RB, Myc, and Notch-signaling genes, has generated hair cell-like cells in the adult cochlea both in vitro and in vivo. The epigenetic mechanism has been studied in hair cell development and regeneration. Regeneration of hair cell function has a very limited progress, which lacks in-vitro and in-vivo electrophysiology data. SUMMARY Regeneration of adult auditory hair cells remains a major challenge. Manipulation of multiple genes and pathways together with epigenetic regulation might potentially regenerate functional hair cells in the adult mammalian cochlea.
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Affiliation(s)
- Zhengqing Hu
- John D. Dingell VA Medical Center
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit
| | - Aditi Singh
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit
| | - Dennis Bojrab
- Michigan Ear Institute, Farmington Hills, Michigan, USA
| | - Nathan Sim
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit
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16
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Xu S, Yang N. Research Progress on the Mechanism of Cochlear Hair Cell Regeneration. Front Cell Neurosci 2021; 15:732507. [PMID: 34489646 PMCID: PMC8417573 DOI: 10.3389/fncel.2021.732507] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 07/28/2021] [Indexed: 12/26/2022] Open
Abstract
Mammalian inner ear hair cells do not have the ability to spontaneously regenerate, so their irreversible damage is the main cause of sensorineural hearing loss. The damage and loss of hair cells are mainly caused by factors such as aging, infection, genetic factors, hypoxia, autoimmune diseases, ototoxic drugs, or noise exposure. In recent years, research on the regeneration and functional recovery of mammalian auditory hair cells has attracted more and more attention in the field of auditory research. How to regenerate and protect hair cells or auditory neurons through biological methods and rebuild auditory circuits and functions are key scientific issues that need to be resolved in this field. This review mainly summarizes and discusses the recent research progress in gene therapy and molecular mechanisms related to hair cell regeneration in the field of sensorineural hearing loss.
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Affiliation(s)
- Shan Xu
- Department of Otolaryngology, The First Hospital of China Medical University, Shenyang, China
| | - Ning Yang
- Department of Otolaryngology, The First Hospital of China Medical University, Shenyang, China
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17
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Erni ST, Gill JC, Palaferri C, Fernandes G, Buri M, Lazarides K, Grandgirard D, Edge ASB, Leib SL, Roccio M. Hair Cell Generation in Cochlear Culture Models Mediated by Novel γ-Secretase Inhibitors. Front Cell Dev Biol 2021; 9:710159. [PMID: 34485296 PMCID: PMC8414802 DOI: 10.3389/fcell.2021.710159] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 07/26/2021] [Indexed: 12/30/2022] Open
Abstract
Sensorineural hearing loss is prevalent within society affecting the quality of life of 460 million worldwide. In the majority of cases, this is due to insult or degeneration of mechanosensory hair cells in the cochlea. In adult mammals, hair cell loss is irreversible as sensory cells are not replaced spontaneously. Genetic inhibition of Notch signaling had been shown to induce hair cell formation by transdifferentiation of supporting cells in young postnatal rodents and provided an impetus for targeting Notch pathway with small molecule inhibitors for hearing restoration. Here, the oto-regenerative potential of different γ-secretase inhibitors (GSIs) was evaluated in complementary assay models, including cell lines, organotypic cultures of the organ of Corti and cochlear organoids to characterize two novel GSIs (CPD3 and CPD8). GSI-treatment induced hair cell gene expression in all these models and was effective in increasing hair cell numbers, in particular outer hair cells, both in baseline conditions and in response to ototoxic damage. Hair cells were generated from transdifferentiation of supporting cells. Similar findings were obtained in cochlear organoid cultures, used for the first time to probe regeneration following sisomicin-induced damage. Finally, effective absorption of a novel GSI through the round window membrane and hair cell induction was attained in a whole cochlea culture model and in vivo pharmacokinetic comparisons of transtympanic delivery of GSIs and different vehicle formulations were successfully conducted in guinea pigs. This preclinical evaluation of targeting Notch signaling with novel GSIs illustrates methods of characterization for hearing restoration molecules, enabling translation to more complex animal studies and clinical research.
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Affiliation(s)
- Silvia T Erni
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland.,Cluster for Regenerative Neuroscience, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland.,Laboratory of Inner Ear Research, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - John C Gill
- Audion Therapeutics B.V., Amsterdam, Netherlands
| | - Carlotta Palaferri
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland.,Cluster for Regenerative Neuroscience, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland.,Laboratory of Inner Ear Research, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Gabriella Fernandes
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland.,Cluster for Regenerative Neuroscience, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland.,Laboratory of Inner Ear Research, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Michelle Buri
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland.,Cluster for Regenerative Neuroscience, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland.,Laboratory of Inner Ear Research, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | | | - Denis Grandgirard
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland.,Cluster for Regenerative Neuroscience, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Albert S B Edge
- Massachusetts Eye and Ear, Boston, MA, United States.,Harvard Medical School, Boston, MA, United States.,Harvard Stem Cell Institute, Cambridge, MA, United States
| | - Stephen L Leib
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland.,Cluster for Regenerative Neuroscience, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Marta Roccio
- Cluster for Regenerative Neuroscience, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland.,Laboratory of Inner Ear Research, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland.,Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich, Zurich, Switzerland.,Department of Otorhinolaryngology, University of Zurich, Zurich, Switzerland
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18
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Enhancer decommissioning imposes an epigenetic barrier to sensory hair cell regeneration. Dev Cell 2021; 56:2471-2485.e5. [PMID: 34331868 DOI: 10.1016/j.devcel.2021.07.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/24/2021] [Accepted: 07/08/2021] [Indexed: 01/02/2023]
Abstract
Adult mammalian tissues such as heart, brain, retina, and the sensory structures of the inner ear do not effectively regenerate, although a latent capacity for regeneration exists at embryonic and perinatal times. We explored the epigenetic basis for this latent regenerative potential in the mouse inner ear and its rapid loss during maturation. In perinatal supporting cells, whose fate is maintained by Notch-mediated lateral inhibition, the hair cell enhancer network is epigenetically primed (H3K4me1) but silenced (active H3K27 de-acetylation and trimethylation). Blocking Notch signaling during the perinatal period of plasticity rapidly eliminates epigenetic silencing and allows supporting cells to transdifferentiate into hair cells. Importantly, H3K4me1 priming of the hair cell enhancers in supporting cells is removed during the first post-natal week, coinciding with the loss of transdifferentiation potential. We hypothesize that enhancer decommissioning during cochlear maturation contributes to the failure of hair cell regeneration in the mature organ of Corti.
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19
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Ballesteros A, Fitzgerald TS, Swartz KJ. Expression of a membrane-targeted fluorescent reporter disrupts auditory hair cell mechanoelectrical transduction and causes profound deafness. Hear Res 2021; 404:108212. [PMID: 33667877 PMCID: PMC8035305 DOI: 10.1016/j.heares.2021.108212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 02/11/2021] [Accepted: 02/13/2021] [Indexed: 11/22/2022]
Abstract
The reporter mT/mG mice expressing a membrane-targeted fluorescent protein are becoming widely used to study the auditory and vestibular system due to its versatility. Here we show that high expression levels of the fluorescent mtdTomato reporter affect the function of the sensory hair cells and the auditory performance of mT/mG transgenic mice. Auditory brainstem responses and distortion product otoacoustic emissions revealed that adult mT/mG homozygous mice are profoundly deaf, whereas heterozygous mice present high frequency loss. We explore whether this line would be useful for studying and visualizing the membrane of auditory hair cells by airyscan super-resolution confocal microscopy. Membrane localization of the reporter was observed in hair cells of the cochlea, facilitating imaging of both cell bodies and stereocilia bundles without altering cellular architecture or the expression of the integral membrane motor protein prestin. Remarkably, hair cells from mT/mG homozygous mice failed to uptake the FM1-43 dye and to locate TMC1 at the stereocilia, indicating defective mechanotransduction machinery. Our work emphasizes that precautions must be considered when working with reporter mice and highlights the potential role of the cellular membrane in maintaining functional hair cells and ensuring proper hearing.
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Affiliation(s)
- Angela Ballesteros
- Molecular Physiology and Biophysics Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
| | - Tracy S Fitzgerald
- Mouse Auditory Testing Core, National Institute on Deafness and other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, United States
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
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20
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Gao J, Fan L, Zhao L, Su Y. The interaction of Notch and Wnt signaling pathways in vertebrate regeneration. CELL REGENERATION (LONDON, ENGLAND) 2021; 10:11. [PMID: 33791915 PMCID: PMC8012441 DOI: 10.1186/s13619-020-00072-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 12/14/2020] [Indexed: 12/21/2022]
Abstract
Regeneration is an evolutionarily conserved process in animal kingdoms, however, the regenerative capacities differ from species and organ/tissues. Mammals possess very limited regenerative potential to replace damaged organs, whereas non-mammalian species usually have impressive abilities to regenerate organs. The regeneration process requires proper spatiotemporal regulation from key signaling pathways. The canonical Notch and Wnt signaling pathways, two fundamental signals guiding animal development, have been demonstrated to play significant roles in the regeneration of vertebrates. In recent years, increasing evidence has implicated the cross-talking between Notch and Wnt signals during organ regeneration. In this review, we summarize the roles of Notch signaling and Wnt signaling during several representative organ regenerative events, emphasizing the functions and molecular bases of their interplay in these processes, shedding light on utilizing these two signaling pathways to enhance regeneration in mammals and design legitimate therapeutic strategies.
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Affiliation(s)
- Junying Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, Shandong, China.,College of Fisheries, Ocean University of China, Qingdao, 266003, Shandong, China
| | - Lixia Fan
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, Shandong, China.,College of Fisheries, Ocean University of China, Qingdao, 266003, Shandong, China
| | - Long Zhao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, Shandong, China. .,College of Fisheries, Ocean University of China, Qingdao, 266003, Shandong, China.
| | - Ying Su
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, Shandong, China. .,College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, Shandong, China.
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21
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Iyer AA, Groves AK. Transcription Factor Reprogramming in the Inner Ear: Turning on Cell Fate Switches to Regenerate Sensory Hair Cells. Front Cell Neurosci 2021; 15:660748. [PMID: 33854418 PMCID: PMC8039129 DOI: 10.3389/fncel.2021.660748] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/08/2021] [Indexed: 12/15/2022] Open
Abstract
Non-mammalian vertebrates can restore their auditory and vestibular hair cells naturally by triggering the regeneration of adjacent supporting cells. The transcription factor ATOH1 is a key regulator of hair cell development and regeneration in the inner ear. Following the death of hair cells, supporting cells upregulate ATOH1 and give rise to new hair cells. However, in the mature mammalian cochlea, such natural regeneration of hair cells is largely absent. Transcription factor reprogramming has been used in many tissues to convert one cell type into another, with the long-term hope of achieving tissue regeneration. Reprogramming transcription factors work by altering the transcriptomic and epigenetic landscapes in a target cell, resulting in a fate change to the desired cell type. Several studies have shown that ATOH1 is capable of reprogramming cochlear non-sensory tissue into cells resembling hair cells in young animals. However, the reprogramming ability of ATOH1 is lost with age, implying that the potency of individual hair cell-specific transcription factors may be reduced or lost over time by mechanisms that are still not clear. To circumvent this, combinations of key hair cell transcription factors have been used to promote hair cell regeneration in older animals. In this review, we summarize recent findings that have identified and studied these reprogramming factor combinations for hair cell regeneration. Finally, we discuss the important questions that emerge from these findings, particularly the feasibility of therapeutic strategies using reprogramming factors to restore human hearing in the future.
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Affiliation(s)
- Amrita A. Iyer
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
- Program in Genetics & Genomics, Houston, TX, United States
| | - Andrew K. Groves
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
- Program in Genetics & Genomics, Houston, TX, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
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22
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LIN28B/ let-7 control the ability of neonatal murine auditory supporting cells to generate hair cells through mTOR signaling. Proc Natl Acad Sci U S A 2020; 117:22225-22236. [PMID: 32826333 DOI: 10.1073/pnas.2000417117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mechano-sensory hair cells within the inner ear cochlea are essential for the detection of sound. In mammals, cochlear hair cells are only produced during development and their loss, due to disease or trauma, is a leading cause of deafness. In the immature cochlea, prior to the onset of hearing, hair cell loss stimulates neighboring supporting cells to act as hair cell progenitors and produce new hair cells. However, for reasons unknown, such regenerative capacity (plasticity) is lost once supporting cells undergo maturation. Here, we demonstrate that the RNA binding protein LIN28B plays an important role in the production of hair cells by supporting cells and provide evidence that the developmental drop in supporting cell plasticity in the mammalian cochlea is, at least in part, a product of declining LIN28B-mammalian target of rapamycin (mTOR) activity. Employing murine cochlear organoid and explant cultures to model mitotic and nonmitotic mechanisms of hair cell generation, we show that loss of LIN28B function, due to its conditional deletion, or due to overexpression of the antagonistic miRNA let-7g, suppressed Akt-mTOR complex 1 (mTORC1) activity and renders young, immature supporting cells incapable of generating hair cells. Conversely, we found that LIN28B overexpression increased Akt-mTORC1 activity and allowed supporting cells that were undergoing maturation to de-differentiate into progenitor-like cells and to produce hair cells via mitotic and nonmitotic mechanisms. Finally, using the mTORC1 inhibitor rapamycin, we demonstrate that LIN28B promotes supporting cell plasticity in an mTORC1-dependent manner.
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23
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Zhang S, Qiang R, Dong Y, Zhang Y, Chen Y, Zhou H, Gao X, Chai R. Hair cell regeneration from inner ear progenitors in the mammalian cochlea. AMERICAN JOURNAL OF STEM CELLS 2020; 9:25-35. [PMID: 32699655 PMCID: PMC7364385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/10/2020] [Indexed: 06/11/2023]
Abstract
Cochlear hair cells (HCs) are the mechanoreceptors of the auditory system, and because these cells cannot be spontaneously regenerated in adult mammals, hearing loss due to HC damage is permanent. However, cochleae of neonatal mice harbor some progenitor cells that retain limited ability to give rise to new HCs in vivo. Here we review the regulatory factors, signaling pathways, and epigenetic factors that have been reported to play roles in HC regeneration in the neonatal mammalian cochlea.
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Affiliation(s)
- Shasha Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing 210096, China
| | - Ruiying Qiang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing 210096, China
| | - Ying Dong
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing 210096, China
| | - Yuan Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing 210096, China
| | - Yin Chen
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory)Nanjing 210008, China
| | - Han Zhou
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory)Nanjing 210008, China
| | - Xia Gao
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory)Nanjing 210008, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing 210096, China
- Co-Innovation Center of Neuroregeneration, Nantong UniversityNantong 226001, China
- Institute for Stem Cell and Regeneration, Chinese Academy of ScienceBeijing, China
- Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast UniversityNanjing 211189, China
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory)Nanjing 210008, China
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24
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Cheng C, Wang Y, Guo L, Lu X, Zhu W, Muhammad W, Zhang L, Lu L, Gao J, Tang M, Chen F, Gao X, Li H, Chai R. Age-related transcriptome changes in Sox2+ supporting cells in the mouse cochlea. Stem Cell Res Ther 2019; 10:365. [PMID: 31791390 PMCID: PMC6889721 DOI: 10.1186/s13287-019-1437-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/29/2019] [Accepted: 10/01/2019] [Indexed: 12/17/2022] Open
Abstract
Background Inner ear supporting cells (SCs) in the neonatal mouse cochlea are a potential source for hair cell (HC) regeneration, but several studies have shown that the regeneration ability of SCs decreases dramatically as mice age and that lost HCs cannot be regenerated in adult mice. To better understand how SCs might be better used to regenerate HCs, it is important to understand how the gene expression profile changes in SCs at different ages. Methods Here, we used Sox2GFP/+ mice to isolate the Sox2+ SCs at postnatal day (P)3, P7, P14, and P30 via flow cytometry. Next, we used RNA-seq to determine the transcriptome expression profiles of P3, P7, P14, and P30 SCs. To further analyze the relationships between these age-related and differentially expressed genes in Sox2+ SCs, we performed gene ontology (GO) analysis. Results Consistent with previous reports, we also found that the proliferation and HC regeneration ability of isolated Sox2+ SCs significantly decreased as mice aged. We identified numerous genes that are enriched and differentially expressed in Sox2+ SCs at four different postnatal ages, including cell cycle genes, signaling pathway genes, and transcription factors that might be involved in regulating the proliferation and HC differentiation ability of SCs. We thus present a set of genes that might regulate the proliferation and HC regeneration ability of SCs, and these might serve as potential new therapeutic targets for HC regeneration. Conclusions In our research, we found several genes that might play an important role in regulating the proliferation and HC regeneration ability of SCs. These datasets are expected to serve as a resource to provide potential new therapeutic targets for regulating the ability of SCs to regenerate HCs in postnatal mammals.
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Affiliation(s)
- Cheng Cheng
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, No. 321 Zhongshan Road, Nanjing, 210008, China.,Research Institute of Otolaryngology, No. 321 Zhongshan Road, Nanjing, 210008, China
| | - Yunfeng Wang
- Shanghai Fenyang Vision & Audition Center, Shanghai, China.,ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Room 611, Building 9, No. 83, Fenyang Road, Xuhui District, Shanghai, 200031, China
| | - Luo Guo
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Room 611, Building 9, No. 83, Fenyang Road, Xuhui District, Shanghai, 200031, China
| | - Xiaoling Lu
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Room 611, Building 9, No. 83, Fenyang Road, Xuhui District, Shanghai, 200031, China
| | - Weijie Zhu
- MOE Key Laboratory for Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Co-Innovation Center of Neuroregeneration, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Waqas Muhammad
- MOE Key Laboratory for Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Co-Innovation Center of Neuroregeneration, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China.,Department of Biotechnology, Federal Urdu University of Arts, Science and Technology, Gulshan-e-Iqbal Campus, Karachi, Pakistan
| | - Liyan Zhang
- MOE Key Laboratory for Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Co-Innovation Center of Neuroregeneration, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Ling Lu
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, No. 321 Zhongshan Road, Nanjing, 210008, China
| | - Junyan Gao
- Jiangsu Rehabilitation Research Center for Hearing and Speech Impairment, Nanjing, 210004, Jiangsu, China
| | - Mingliang Tang
- MOE Key Laboratory for Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Co-Innovation Center of Neuroregeneration, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Fangyi Chen
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Xia Gao
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, No. 321 Zhongshan Road, Nanjing, 210008, China.
| | - Huawei Li
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Room 611, Building 9, No. 83, Fenyang Road, Xuhui District, Shanghai, 200031, China.
| | - Renjie Chai
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Room 611, Building 9, No. 83, Fenyang Road, Xuhui District, Shanghai, 200031, China. .,MOE Key Laboratory for Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Co-Innovation Center of Neuroregeneration, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China. .,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China. .,Institute for Stem Cell and Regeneration, Chinese Academy of Science, Beijing, China. .,Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, 100069, China.
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25
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Novel insights into inner ear development and regeneration for targeted hearing loss therapies. Hear Res 2019; 397:107859. [PMID: 31810596 DOI: 10.1016/j.heares.2019.107859] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/06/2019] [Accepted: 11/25/2019] [Indexed: 02/06/2023]
Abstract
Sensorineural hearing loss is the most common sensory deficit in humans. Despite the global scale of the problem, only limited treatment options are available today. The mammalian inner ear is a highly specialized postmitotic organ, which lacks proliferative or regenerative capacity. Since the discovery of hair cell regeneration in non-mammalian species however, much attention has been placed on identifying possible strategies to reactivate similar responses in humans. The development of successful regenerative approaches for hearing loss strongly depends on a detailed understanding of the mechanisms that control human inner ear cellular specification, differentiation and function, as well as on the development of robust in vitro cellular assays, based on human inner ear cells, to study these processes and optimize therapeutic interventions. We summarize here some aspects of inner ear development and strategies to induce regeneration that have been investigated in rodents. Moreover, we discuss recent findings in human inner ear development and compare the results with findings from animal models. Finally, we provide an overview of strategies for in vitro generation of human sensory cells from pluripotent and somatic progenitors that may provide a platform for drug development and validation of therapeutic strategies in vitro.
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26
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Cigliola V, Ghila L, Chera S, Herrera PL. Tissue repair brakes: A common paradigm in the biology of regeneration. Stem Cells 2019; 38:330-339. [PMID: 31722129 DOI: 10.1002/stem.3118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 10/09/2019] [Accepted: 10/20/2019] [Indexed: 12/12/2022]
Abstract
To date, most attention on tissue regeneration has focused on the exploration of positive cues promoting or allowing the engagement of natural cellular restoration upon injury. In contrast, the signals fostering cell identity maintenance in the vertebrate body have been poorly investigated; yet they are crucial, for their counteraction could become a powerful method to induce and modulate regeneration. Here we review the mechanisms inhibiting pro-regenerative spontaneous adaptive cell responses in different model organisms and organs. The pharmacological or genetic/epigenetic modulation of such regenerative brakes could release a dormant but innate adaptive competence of certain cell types and therefore boost tissue regeneration in different situations.
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Affiliation(s)
- Valentina Cigliola
- Department of Cell Biology, Regeneration Next, Duke University Medical Center, Durham, North Carolina
| | - Luiza Ghila
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Simona Chera
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Pedro L Herrera
- Department of Genetic Medicine & Development, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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27
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Abstract
Deafness or hearing deficits are debilitating conditions. They are often caused by loss of sensory hair cells or defects in their function. In contrast to mammals, nonmammalian vertebrates robustly regenerate hair cells after injury. Studying the molecular and cellular basis of nonmammalian vertebrate hair cell regeneration provides valuable insights into developing cures for human deafness. In this review, we discuss the current literature on hair cell regeneration in the context of other models for sensory cell regeneration, such as the retina and the olfactory epithelium. This comparison reveals commonalities with, as well as differences between, the different regenerating systems, which begin to define a cellular and molecular blueprint of regeneration. In addition, we propose how new technical advances can address outstanding questions in the field.
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Affiliation(s)
- Nicolas Denans
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA;
| | - Sungmin Baek
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA;
| | - Tatjana Piotrowski
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA;
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28
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Roccio M, Edge ASB. Inner ear organoids: new tools to understand neurosensory cell development, degeneration and regeneration. Development 2019; 146:146/17/dev177188. [PMID: 31477580 DOI: 10.1242/dev.177188] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The development of therapeutic interventions for hearing loss requires fundamental knowledge about the signaling pathways controlling tissue development as well as the establishment of human cell-based assays to validate therapeutic strategies ex vivo Recent advances in the field of stem cell biology and organoid culture systems allow the expansion and differentiation of tissue-specific progenitors and pluripotent stem cells in vitro into functional hair cells and otic-like neurons. We discuss how inner ear organoids have been developed and how they offer for the first time the opportunity to validate drug-based therapies, gene-targeting approaches and cell replacement strategies.
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Affiliation(s)
- Marta Roccio
- Inner Ear Research Laboratory, Department of Biomedical Research (DBMR), University of Bern, Bern 3008, Switzerland .,Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern 3010, Switzerland
| | - Albert S B Edge
- Department of Otolaryngology, Harvard Medical School, Boston, MA 02115, USA.,Eaton-Peabody Laboratory, Massachusetts Eye and Ear, Boston, MA 02114, USA.,Harvard Stem Cell Institute, Cambridge, MA 02138, USA
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29
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Ma Y, Wise AK, Shepherd RK, Richardson RT. New molecular therapies for the treatment of hearing loss. Pharmacol Ther 2019; 200:190-209. [PMID: 31075354 DOI: 10.1016/j.pharmthera.2019.05.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/02/2019] [Indexed: 12/11/2022]
Abstract
An estimated 466 million people suffer from hearing loss worldwide. Sensorineural hearing loss is characterized by degeneration of key structures of the sensory pathway in the cochlea such as the sensory hair cells, the primary auditory neurons and their synaptic connection to the hair cells - the ribbon synapse. Various strategies to protect or regenerate these sensory cells and structures are the subject of intensive research. Yet despite recent advances in our understandings of the capacity of the cochlea for repair and regeneration there are currently no pharmacological or biological interventions for hearing loss. Current research focusses on localized cochlear drug, gene and cell-based therapies. One of the more promising drug-based therapies is based on neurotrophic factors for the repair of the ribbon synapse after noise exposure, as well as preventing loss of primary auditory neurons and regrowth of the auditory neuron fibers after severe hearing loss. Drug therapy delivery technologies are being employed to address the specific needs of neurotrophin and other therapies for hearing loss that include the need for high doses, long-term delivery, localised or cell-specific targeting and techniques for their safe and efficacious delivery to the cochlea. Novel biomaterials are enabling high payloads of drugs to be administered to the cochlea with subsequent slow-release properties that are proving to be beneficial for treating hearing loss. In parallel, new gene therapy technologies are addressing the need for cell specificity and high efficacy for the treatment of both genetic and acquired hearing loss with promising reports of hearing recovery. Some biomaterials and cell therapies are being used in conjunction with the cochlear implant ensuring therapeutic benefit to the primary neurons during electrical stimulation. This review will introduce the auditory system, hearing loss and the potential for repair and regeneration in the cochlea. Drug delivery to the cochlea will then be reviewed, with a focus on new biomaterials, gene therapy technologies, cell therapy and the use of the cochlear implant as a vehicle for drug delivery. With the current pre-clinical research effort into therapies for hearing loss, including clinical trials for gene therapy, the future for the treatment for hearing loss is looking bright.
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Affiliation(s)
- Yutian Ma
- Bionics Institute, East Melbourne, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Australia; University of Melbourne, Department of Chemical Engineering, Parkville, Victoria, Australia
| | - Andrew K Wise
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia
| | - Robert K Shepherd
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia
| | - Rachael T Richardson
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia.
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30
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Walters BJ, Cox BC. Approaches for the study of epigenetic modifications in the inner ear and related tissues. Hear Res 2019; 376:69-85. [PMID: 30679030 PMCID: PMC6456365 DOI: 10.1016/j.heares.2019.01.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/12/2018] [Accepted: 01/11/2019] [Indexed: 12/12/2022]
Abstract
DNA methylation and histone modifications such as methylation, acetylation, and phosphorylation, are two types of epigenetic modifications that alter gene expression. These additions to DNA regulatory elements or to the tails of histones can be inherited or can also occur de novo. Since epigenetic modifications can have significant effects on various processes at both the cellular and organismal level, there has been a rapid increase in research on this topic throughout all fields of biology in recent years. However, epigenetic research is relativity new for the inner ear field, likely due to the limited number of cells present and their quiescent nature. Here, we provide an overview of methods used to detect DNA methylation and histone modifications with a focus on those that have been validated for use with limited cell numbers and a discussion of the strengths and limitations for each. We also provide examples for how these methods have been used to investigate the epigenetic landscape in the inner ear and related tissues.
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Affiliation(s)
- Bradley J Walters
- Departments of Neurobiology and Anatomical Sciences, and of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Brandon C Cox
- Departments of Pharmacology and Surgery, Division of Otolaryngology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA.
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31
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McGovern MM, Randle MR, Cuppini CL, Graves KA, Cox BC. Multiple supporting cell subtypes are capable of spontaneous hair cell regeneration in the neonatal mouse cochlea. Development 2019; 146:146/4/dev171009. [PMID: 30770379 DOI: 10.1242/dev.171009] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 01/09/2019] [Indexed: 12/20/2022]
Abstract
Supporting cells (SCs) are known to spontaneously regenerate hair cells (HCs) in the neonatal mouse cochlea, yet little is known about the relative contribution of distinct SC subtypes which differ in morphology and function. We have previously shown that HC regeneration is linked to Notch signaling, and some SC subtypes, but not others, lose expression of the Notch effector Hes5 Other work has demonstrated that Lgr5-positive SCs have an increased capacity to regenerate HCs; however, several SC subtypes express Lgr5. To further investigate the source for spontaneous HC regeneration, we used three CreER lines to fate-map distinct groups of SCs during regeneration. Fate-mapping either alone or combined with a mitotic tracer showed that pillar and Deiters' cells contributed more regenerated HCs overall. However, when normalized to the total fate-mapped population, pillar, Deiters', inner phalangeal and border cells had equal capacity to regenerate HCs, and all SC subtypes could divide after HC damage. Investigating the mechanisms that allow individual SC subtypes to regenerate HCs and the postnatal changes that occur in each group during maturation could lead to therapies for hearing loss.
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Affiliation(s)
- Melissa M McGovern
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA
| | - Michelle R Randle
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA
| | - Candice L Cuppini
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA
| | - Kaley A Graves
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA
| | - Brandon C Cox
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA .,Department of Surgery, Division of Otolaryngology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA
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32
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Nam YH, Rodriguez I, Jeong SY, Pham TNM, Nuankaew W, Kim YH, Castañeda R, Jeong SY, Park MS, Lee KW, Lee JS, Kim DH, Park YH, Kim SH, Moon IS, Choung SY, Hong BN, Jeong KW, Kang TH. Avocado Oil Extract Modulates Auditory Hair Cell Function through the Regulation of Amino Acid Biosynthesis Genes. Nutrients 2019; 11:nu11010113. [PMID: 30626089 PMCID: PMC6356572 DOI: 10.3390/nu11010113] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 12/24/2018] [Accepted: 01/05/2019] [Indexed: 12/21/2022] Open
Abstract
Sensorineural hearing loss (SNHL) is one of the most common causes of disability, affecting over 466 million people worldwide. However, prevention or therapy of SNHL has not been widely studied. Avocado oil has shown many health benefits but it has not yet been studied in regards to SNHL. Therefore, we aimed to investigate the efficacy of avocado oil on SNHL in vitro and in vivo and elucidate its mode of action. For the present study, we used enhanced functional avocado oil extract (DKB122). DKB122 led to recovery of otic hair cells in zebrafish after neomycin-induced otic cell damage. Also, DKB122 improved auditory sensory transmission function in a mouse model of noise induced-hearing loss and protected sensory hair cells in the cochlea. In addition, RNA sequencing was performed to elucidate the mechanism involved. KEGG pathway enrichment analysis of differentially expressed genes showed that DKB122 protected House Ear Institute-Organ of Corti 1 (HEI-OC1) cells against neomycin-related alterations in gene expression due to oxidative stress, cytokine production and protein synthesis.
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MESH Headings
- Amino Acids/biosynthesis
- Animals
- Auditory Perception/drug effects
- Cochlea/cytology
- Cochlea/drug effects
- Cochlea/metabolism
- Gene Expression Regulation/drug effects
- Hair Cells, Auditory/drug effects
- Hair Cells, Auditory/metabolism
- Hair Cells, Auditory/physiology
- Hearing Loss, Noise-Induced/drug therapy
- Hearing Loss, Noise-Induced/genetics
- Hearing Loss, Noise-Induced/metabolism
- Hearing Loss, Noise-Induced/physiopathology
- Hearing Loss, Sensorineural/drug therapy
- Hearing Loss, Sensorineural/genetics
- Hearing Loss, Sensorineural/metabolism
- Hearing Loss, Sensorineural/physiopathology
- Metabolic Networks and Pathways/drug effects
- Metabolic Networks and Pathways/genetics
- Mice
- Persea/chemistry
- Phytotherapy
- Plant Extracts/pharmacology
- Plant Extracts/therapeutic use
- Plant Oils/pharmacology
- Plant Oils/therapeutic use
- Sequence Analysis, RNA
- Zebrafish
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Affiliation(s)
- Youn Hee Nam
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Isabel Rodriguez
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Seo Yeon Jeong
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, Incheon 21936, Korea.
| | - Thu Nguyen Minh Pham
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, Incheon 21936, Korea.
| | - Wanlapa Nuankaew
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Yun Hee Kim
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Rodrigo Castañeda
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Seo Yule Jeong
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Min Seon Park
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Kye Wan Lee
- R&D Center, Dongkook Pharm. Co., Ltd., Gyeonggi 16229, Korea.
| | - Jung Suk Lee
- R&D Center, Dongkook Pharm. Co., Ltd., Gyeonggi 16229, Korea.
| | - Do Hoon Kim
- R&D Center, Dongkook Pharm. Co., Ltd., Gyeonggi 16229, Korea.
| | - Yu Hwa Park
- R&D Center, Dongkook Pharm. Co., Ltd., Gyeonggi 16229, Korea.
| | - Seung Hyun Kim
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon 21983, Korea.
| | - In Seok Moon
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul 03722, Korea.
| | - Se-Young Choung
- Department of Preventive Pharmacy and Toxicology, College of Pharmacy, Kyung Hee University, Seoul 02453, Korea.
| | - Bin Na Hong
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Kwang Won Jeong
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, Incheon 21936, Korea.
| | - Tong Ho Kang
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
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34
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Molecular characterization and prospective isolation of human fetal cochlear hair cell progenitors. Nat Commun 2018; 9:4027. [PMID: 30279445 PMCID: PMC6168603 DOI: 10.1038/s41467-018-06334-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 08/27/2018] [Indexed: 01/02/2023] Open
Abstract
Sensory hair cells located in the organ of Corti are essential for cochlear mechanosensation. Their loss is irreversible in humans resulting in permanent hearing loss. The development of therapeutic interventions for hearing loss requires fundamental knowledge about similarities and potential differences between animal models and human development as well as the establishment of human cell based-assays. Here we analyze gene and protein expression of the developing human inner ear in a temporal window spanning from week 8 to 12 post conception, when cochlear hair cells become specified. Utilizing surface markers for the cochlear prosensory domain, namely EPCAM and CD271, we purify postmitotic hair cell progenitors that, when placed in culture in three-dimensional organoids, regain proliferative potential and eventually differentiate to hair cell-like cells in vitro. These results provide a foundation for comparative studies with otic cells generated from human pluripotent stem cells and for establishing novel platforms for drug validation. Hearing requires mechanosensitive hair cells in the organ of Corti, which derive from progenitors of the cochlear duct. Here the authors examine human inner ear development by studying key developmental markers and describe organoid cultures from human cochlear duct progenitors for in vitro hair cell differentiation.
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35
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Abstract
Sensorineural hearing impairment is the most common sensory disorder and a major health and socio-economic issue in industrialized countries. It is primarily due to the degeneration of mechanosensory hair cells and spiral ganglion neurons in the cochlea via complex pathophysiological mechanisms. These occur following acute and/or chronic exposure to harmful extrinsic (e.g., ototoxic drugs, noise...) and intrinsic (e.g., aging, genetic) causative factors. No clinical therapies currently exist to rescue the dying sensorineural cells or regenerate these cells once lost. Recent studies have, however, provided renewed hope, with insights into the therapeutic targets allowing the prevention and treatment of ototoxic drug- and noise-induced, age-related hearing loss as well as cochlear cell degeneration. Moreover, genetic routes involving the replacement or corrective editing of mutant sequences or defected genes are showing promise, as are cell-replacement therapies to repair damaged cells for the future restoration of hearing in deaf people. This review begins by recapitulating our current understanding of the molecular pathways that underlie cochlear sensorineural damage, as well as the survival signaling pathways that can provide endogenous protection and tissue rescue. It then guides the reader through to the recent discoveries in pharmacological, gene and cell therapy research towards hearing protection and restoration as well as their potential clinical application.
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Affiliation(s)
- Jing Wang
- INSERM UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; and University of Montpellier, Montpellier, France
| | - Jean-Luc Puel
- INSERM UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; and University of Montpellier, Montpellier, France
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36
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McGovern MM, Zhou L, Randle MR, Cox BC. Spontaneous Hair Cell Regeneration Is Prevented by Increased Notch Signaling in Supporting Cells. Front Cell Neurosci 2018; 12:120. [PMID: 29780306 PMCID: PMC5945818 DOI: 10.3389/fncel.2018.00120] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/13/2018] [Indexed: 11/13/2022] Open
Abstract
During embryonic development, differentiation of cochlear progenitor cells into hair cells (HCs) or supporting cells (SCs) is partially controlled through Notch signaling. Many studies have shown that inhibition of Notch signaling allows SCs to convert into HCs in both normal and drug damaged neonatal mouse cochleae. This mechanism is also implicated during HC regeneration in non-mammalian vertebrates; however, the mechanism of spontaneous HC regeneration in the neonatal mouse cochlea is less understood. While inhibition of Notch signaling can force SCs to convert into HCs and increase the number of regenerated HCs, it is currently unknown whether this pathway is involved in spontaneous HC regeneration observed in vivo. Therefore, we investigated the role of Notch signaling during the spontaneous HC regeneration process using Atoh1-CreERTM::Rosa26loxP-stop-loxP-DTA/+ mice injected with tamoxifen at postnatal day (P) 0 and P1 to ablate HCs and stimulate spontaneous HC regeneration. Expression changes of genes in the Notch pathway were measured using immunostaining and in situ hybridization, with most changes observed in the apical one-third of the cochlea where the majority of HC regeneration occurs. Expression of the Notch target genes Hes1, Hes5, Hey1, HeyL, and Jagged1 were decreased. To investigate whether reduction of Notch signaling is involved in the spontaneous HC regeneration process, we overexpressed the Notch1 intracellular fragment (N1ICD) in cochlear SCs and other non-sensory epithelial cells in the context of HC damage. Specifically, Atoh1-CreERTM::Rosa26loxP-stop-loxP-DTA/+::Sox10rtTA::TetO-LacZ::TetO-N1ICD mice were injected with tamoxifen at P0/P1 to stimulate spontaneous HC regeneration and given doxycycline from P0-P7 to induce expression of N1ICD as well as LacZ for fate-mapping. We observed a 92% reduction in the number of fate-mapped regenerated HCs in mice with N1ICD overexpression compared to controls with HC damage but no manipulation of Notch signaling. Therefore, we conclude that increased Notch signaling prevents spontaneous HC regeneration from occurring in the neonatal mouse cochlea. Understanding which components of the Notch pathway regulates regenerative plasticity in the neonatal mouse cochlea will inform investigations focused on stimulating HC regeneration in mature cochlea and eventually in humans to treat hearing loss.
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Affiliation(s)
- Melissa M. McGovern
- Department of Pharmacology, School of Medicine, Southern Illinois University, Springfield, IL, United States
| | - Luyi Zhou
- Department of Pharmacology, School of Medicine, Southern Illinois University, Springfield, IL, United States
| | - Michelle R. Randle
- Department of Pharmacology, School of Medicine, Southern Illinois University, Springfield, IL, United States
| | - Brandon C. Cox
- Department of Pharmacology, School of Medicine, Southern Illinois University, Springfield, IL, United States
- Department of Surgery, Division of Otolaryngology, School of Medicine, Southern Illinois University, Springfield, IL, United States
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You D, Guo L, Li W, Sun S, Chen Y, Chai R, Li H. Characterization of Wnt and Notch-Responsive Lgr5+ Hair Cell Progenitors in the Striolar Region of the Neonatal Mouse Utricle. Front Mol Neurosci 2018; 11:137. [PMID: 29760650 PMCID: PMC5937014 DOI: 10.3389/fnmol.2018.00137] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/04/2018] [Indexed: 12/22/2022] Open
Abstract
Dysfunctions in hearing and balance are largely connected with hair cell (HC) loss. Although regeneration of HCs in the adult cochlea does not occur, there is still limited capacity for HC regeneration in the mammalian utricle from a distinct population of supporting cells (SCs). In response to HC damage, these Lgr5+ SCs, especially those in the striolar region, can regenerate HCs. In this study, we isolated Lgr5+ SCs and Plp1+ SCs (which originate from the striolar and extrastriolar regions, respectively) from transgenic mice by flow cytometry so as to compare the properties of these two subsets of SCs. We found that the Lgr5+ progenitors had greater proliferation and HC regeneration ability than the Plp1+ SCs and that the Lgr5+ progenitors responded more strongly to Wnt and Notch signaling than Plp1+ SCs. We then compared the gene expression profiles of the two populations by RNA-Seq and identified several genes that were significantly differentially expressed between the two populations, including genes involved in the cell cycle, transcription and cell signaling pathways. Targeting these genes and pathways might be a potential way to activate HC regeneration.
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Affiliation(s)
- Dan You
- ENT Institute and Otorhinolaryngology, Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Luo Guo
- ENT Institute and Otorhinolaryngology, Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Wenyan Li
- ENT Institute and Otorhinolaryngology, Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Shan Sun
- ENT Institute and Otorhinolaryngology, Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Yan Chen
- ENT Institute and Otorhinolaryngology, Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Institute of Life Sciences, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Huawei Li
- ENT Institute and Otorhinolaryngology, Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Institutes of Biomedical Sciences and The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
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38
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Atkinson PJ, Dong Y, Gu S, Liu W, Najarro EH, Udagawa T, Cheng AG. Sox2 haploinsufficiency primes regeneration and Wnt responsiveness in the mouse cochlea. J Clin Invest 2018; 128:1641-1656. [PMID: 29553487 DOI: 10.1172/jci97248] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 02/01/2018] [Indexed: 12/31/2022] Open
Abstract
During development, Sox2 is indispensable for cell division and differentiation, yet its roles in regenerating tissues are less clear. Here, we used combinations of transgenic mouse models to reveal that Sox2 haploinsufficiency (Sox2haplo) increases rather than impairs cochlear regeneration in vivo. Sox2haplo cochleae had delayed terminal mitosis and ectopic sensory cells, yet normal auditory function. Sox2haplo amplified and expanded domains of damage-induced Atoh1+ transitional cell formation in neonatal cochlea. Wnt activation via β-catenin stabilization (β-cateninGOF) alone failed to induce proliferation or transitional cell formation. By contrast, β-cateninGOF caused proliferation when either Sox2haplo or damage was present, and transitional cell formation when both were present in neonatal, but not mature, cochlea. Mechanistically, Sox2haplo or damaged neonatal cochleae showed lower levels of Sox2 and Hes5, but not of Wnt target genes. Together, our study unveils an interplay between Sox2 and damage in directing tissue regeneration and Wnt responsiveness and thus provides a foundation for potential combinatorial therapies aimed at stimulating mammalian cochlear regeneration to reverse hearing loss in humans.
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Affiliation(s)
- Patrick J Atkinson
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Yaodong Dong
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA.,Department of Otology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
| | - Shuping Gu
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Wenwen Liu
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Elvis Huarcaya Najarro
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Tomokatsu Udagawa
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Alan G Cheng
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
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Regeneration of Cochlear Hair Cells and Hearing Recovery through Hes1 Modulation with siRNA Nanoparticles in Adult Guinea Pigs. Mol Ther 2018; 26:1313-1326. [PMID: 29680697 DOI: 10.1016/j.ymthe.2018.03.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 03/06/2018] [Accepted: 03/06/2018] [Indexed: 12/17/2022] Open
Abstract
Deafness is commonly caused by the irreversible loss of mammalian cochlear hair cells (HCs) due to noise trauma, toxins, or infections. We previously demonstrated that small interfering RNAs (siRNAs) directed against the Notch pathway gene, hairy and enhancer of split 1 (Hes1), encapsulated within biocompatible poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) could regenerate HCs within ototoxin-ablated murine organotypic cultures. In the present study, we delivered this sustained-release formulation of Hes1 siRNA (siHes1) into the cochleae of noise-injured adult guinea pigs. Auditory functional recovery was measured by serial auditory brainstem responses over a nine-week follow-up period, and HC regeneration was evaluated by immunohistological evaluations and scanning electron microscopy. Significant HC restoration and hearing recovery were observed across a broad tonotopic range in ears treated with siHes1 NPs, beginning at three weeks and extending out to nine weeks post-treatment. Moreover, both ectopic and immature HCs were uniquely observed in noise-injured cochleae treated with siHes1 NPs, consistent with de novo HC production. Our results indicate that durable cochlear HCs were regenerated and promoted significant hearing recovery in adult guinea pigs through reversible modulation of Hes1 expression. Therefore, PLGA-NP-mediated delivery of siHes1 to the cochlea represents a promising pharmacologic approach to regenerate functional and sustainable mammalian HCs in vivo.
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Abstract
Presbycusis, or age-related hearing loss (ARHL), is the result of physiologic and pathologic changes associated with advancing age. ARHL presents typically with a high-frequency hearing loss, which contributes to greater trouble hearing consonants within words. Consonants convey the bulk of meaning within a word, and this loss of linguistic information results in complaints associated with ARHL. Hearing aids and cochlear implants significantly improve the lives of older adults with hearing loss, in particular, those with depression and dementia. Successful current research in gene therapy, pharmacotherapy, and stems cells holds the promise of being able to restore native cochlear function.
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Affiliation(s)
- Rohan Patel
- Drexel University College of Medicine, 2900 West Queen Lane, Philadelphia, PA 19129, USA
| | - Brian J McKinnon
- Departments of Otolaryngology-Head and Neck Surgery and Neurosurgery, 219 North Broad Street, 10th Floor, Philadelphia, PA 19107, USA.
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McLean WJ, Yin X, Lu L, Lenz DR, McLean D, Langer R, Karp JM, Edge ASB. Clonal Expansion of Lgr5-Positive Cells from Mammalian Cochlea and High-Purity Generation of Sensory Hair Cells. Cell Rep 2017; 18:1917-1929. [PMID: 28228258 DOI: 10.1016/j.celrep.2017.01.066] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 01/05/2017] [Accepted: 01/25/2017] [Indexed: 12/24/2022] Open
Abstract
Death of cochlear hair cells, which do not regenerate, is a cause of hearing loss in a high percentage of the population. Currently, no approach exists to obtain large numbers of cochlear hair cells. Here, using a small-molecule approach, we show significant expansion (>2,000-fold) of cochlear supporting cells expressing and maintaining Lgr5, an epithelial stem cell marker, in response to stimulation of Wnt signaling by a GSK3β inhibitor and transcriptional activation by a histone deacetylase inhibitor. The Lgr5-expressing cells differentiate into hair cells in high yield. From a single mouse cochlea, we obtained over 11,500 hair cells, compared to less than 200 in the absence of induction. The newly generated hair cells have bundles and molecular machinery for transduction, synapse formation, and specialized hair cell activity. Targeting supporting cells capable of proliferation and cochlear hair cell replacement could lead to the discovery of hearing loss treatments.
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Affiliation(s)
- Will J McLean
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02115, USA; Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA; Program in Speech and Hearing Bioscience and Technology, Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA
| | - Xiaolei Yin
- Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA 02142, USA; Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA
| | - Lin Lu
- Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA 02142, USA; Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Danielle R Lenz
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02115, USA; Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA
| | - Dalton McLean
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02115, USA; Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA
| | - Robert Langer
- Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA 02142, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA; Department of Chemical Engineering, MIT, Cambridge, MA 02142, USA.
| | - Jeffrey M Karp
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA.
| | - Albert S B Edge
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02115, USA; Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA; Program in Speech and Hearing Bioscience and Technology, Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA.
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Wu JS, Vyas P, Glowatzki E, Fuchs PA. Opposing expression gradients of calcitonin-related polypeptide alpha (Calca/Cgrpα) and tyrosine hydroxylase (Th) in type II afferent neurons of the mouse cochlea. J Comp Neurol 2017; 526:425-438. [PMID: 29055051 DOI: 10.1002/cne.24341] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 10/04/2017] [Accepted: 10/10/2017] [Indexed: 12/20/2022]
Abstract
Type II spiral ganglion neurons (SGNs) are small caliber, unmyelinated afferents that extend dendritic arbors hundreds of microns along the cochlear spiral, contacting many outer hair cells (OHCs). Despite these many contacts, type II afferents are insensitive to sound and only weakly depolarized by glutamate release from OHCs. Recent studies suggest that type II afferents may be cochlear nociceptors, and can be excited by ATP released during tissue damage, by analogy to somatic pain-sensing C-fibers. The present work compares the expression patterns among cochlear type II afferents of two genes found in C-fibers: calcitonin-related polypeptide alpha (Calca/Cgrpα), specific to pain-sensing C-fibers, and tyrosine hydroxylase (Th), specific to low-threshold mechanoreceptive C-fibers, which was shown previously to be a selective biomarker of type II versus type I cochlear afferents (Vyas et al., ). Whole-mount cochlear preparations from 3-week- to 2-month-old CGRPα-EGFP (GENSAT) mice showed expression of Cgrpα in a subset of SGNs with type II-like peripheral dendrites extending beneath OHCs. Double labeling with other molecular markers confirmed that the labeled SGNs were neither type I SGNs nor olivocochlear efferents. Cgrpα starts to express in type II SGNs before hearing onset, but the expression level declines in the adult. The expression patterns of Cgrpα and Th formed opposing gradients, with Th being preferentially expressed in apical and Cgrpα in basal type II afferent neurons, indicating heterogeneity among type II afferent neurons. The expression of Th and Cgrpα was not mutually exclusive and co-expression could be observed, most abundantly in the middle cochlear turn.
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Affiliation(s)
- Jingjing Sherry Wu
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,The Center for Hearing and Balance and the Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Pankhuri Vyas
- The Center for Hearing and Balance and the Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Elisabeth Glowatzki
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,The Center for Hearing and Balance and the Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Paul Albert Fuchs
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,The Center for Hearing and Balance and the Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
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Fritzsch B, Elliott KL. Gene, cell, and organ multiplication drives inner ear evolution. Dev Biol 2017; 431:3-15. [PMID: 28866362 DOI: 10.1016/j.ydbio.2017.08.034] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 04/27/2017] [Accepted: 08/25/2017] [Indexed: 12/14/2022]
Abstract
We review the development and evolution of the ear neurosensory cells, the aggregation of neurosensory cells into an otic placode, the evolution of novel neurosensory structures dedicated to hearing and the evolution of novel nuclei in the brain and their input dedicated to processing those novel auditory stimuli. The evolution of the apparently novel auditory system lies in duplication and diversification of cell fate transcription regulation that allows variation at the cellular level [transforming a single neurosensory cell into a sensory cell connected to its targets by a sensory neuron as well as diversifying hair cells], organ level [duplication of organ development followed by diversification and novel stimulus acquisition] and brain nuclear level [multiplication of transcription factors to regulate various neuron and neuron aggregate fate to transform the spinal cord into the unique hindbrain organization]. Tying cell fate changes driven by bHLH and other transcription factors into cell and organ changes is at the moment tentative as not all relevant factors are known and their gene regulatory network is only rudimentary understood. Future research can use the blueprint proposed here to provide both the deeper molecular evolutionary understanding as well as a more detailed appreciation of developmental networks. This understanding can reveal how an auditory system evolved through transformation of existing cell fate determining networks and thus how neurosensory evolution occurred through molecular changes affecting cell fate decision processes. Appreciating the evolutionary cascade of developmental program changes could allow identifying essential steps needed to restore cells and organs in the future.
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Affiliation(s)
- Bernd Fritzsch
- University of Iowa, Department of Biology, Iowa City, IA 52242, United States.
| | - Karen L Elliott
- University of Iowa, Department of Biology, Iowa City, IA 52242, United States
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Diphtheria Toxin-Induced Cell Death Triggers Wnt-Dependent Hair Cell Regeneration in Neonatal Mice. J Neurosci 2017; 36:9479-89. [PMID: 27605621 DOI: 10.1523/jneurosci.2447-15.2016] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 07/20/2016] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED Cochlear hair cells (HCs), the sensory cells that respond to sound, do not regenerate after damage in adult mammals, and their loss is a major cause of deafness. Here we show that HC regeneration in newborn mouse ears occurred spontaneously when the original cells were ablated by treatment with diphtheria toxin (DT) in ears that had been engineered to overexpress the DT receptor, but was not detectable when HCs were ablated in vivo by the aminoglycoside antibiotic neomycin. A variety of Wnts (Wnt1, Wnt2, Wnt2b, Wnt4, Wnt5a, Wnt7b, Wnt9a, Wnt9b, and Wnt11) and Wnt pathway component Krm2 were upregulated after DT damage. Nuclear β-catenin was upregulated in HCs and supporting cells of the DT-damaged cochlea. Pharmacological inhibition of Wnt decreased spontaneous regeneration, confirming a role of Wnt signaling in HC regeneration. Inhibition of Notch signaling further potentiated supporting cell proliferation and HC differentiation that occurred spontaneously. The absence of new HCs in the neomycin ears was correlated to less robust Wnt pathway activation, but the ears subjected to neomycin treatment nonetheless showed increased cell division and HC differentiation after subsequent forced upregulation of β-catenin. These studies suggest, first, that Wnt signaling plays a key role in regeneration, and, second, that the outcome of a regenerative response to damage in the newborn cochlea is determined by reaching a threshold level of Wnt signaling rather than its complete absence or presence. SIGNIFICANCE STATEMENT Sensory HCs of the inner ear do not regenerate in the adult, and their loss is a major cause of deafness. We found that HCs regenerated spontaneously in the newborn mouse after diphtheria toxin (DT)-induced, but not neomycin-induced, HC death. Regeneration depended on activation of Wnt signaling, and regeneration in DT-treated ears correlated to a higher level of Wnt activation than occurred in nonregenerating neomycin-treated ears. This is significant because insufficient regeneration caused by a failure to reach a threshold level of signaling, if true in the adult, has the potential to be exploited for development of clinical approaches for the treatment of deafness caused by HC loss.
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Zhang S, Zhang Y, Yu P, Hu Y, Zhou H, Guo L, Xu X, Zhu X, Waqas M, Qi J, Zhang X, Liu Y, Chen F, Tang M, Qian X, Shi H, Gao X, Chai R. Characterization of Lgr5+ Progenitor Cell Transcriptomes after Neomycin Injury in the Neonatal Mouse Cochlea. Front Mol Neurosci 2017; 10:213. [PMID: 28725177 PMCID: PMC5496572 DOI: 10.3389/fnmol.2017.00213] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 06/16/2017] [Indexed: 12/17/2022] Open
Abstract
Lgr5+ supporting cells (SCs) are enriched hair cell (HC) progenitors in the cochlea. Both in vitro and in vivo studies have shown that HC injury can spontaneously activate Lgr5+ progenitors to regenerate HCs in the neonatal mouse cochlea. Promoting HC regeneration requires the understanding of the mechanism of HC regeneration, and this requires knowledge of the key genes involved in HC injury-induced self-repair responses that promote the proliferation and differentiation of Lgr5+ progenitors. Here, as expected, we found that neomycin-treated Lgr5+ progenitors (NLPs) had significantly greater HC regeneration ability, and greater but not significant proliferation ability compared to untreated Lgr5+ progenitors (ULPs) in response to neomycin exposure. Next, we used RNA-seq analysis to determine the differences in the gene-expression profiles between the transcriptomes of NLPs and ULPs from the neonatal mouse cochlea. We first analyzed the genes that were enriched and differentially expressed in NLPs and ULPs and then analyzed the cell cycle genes, the transcription factors, and the signaling pathway genes that might regulate the proliferation and differentiation of Lgr5+ progenitors. We found 9 cell cycle genes, 88 transcription factors, 8 microRNAs, and 16 cell-signaling pathway genes that were significantly upregulated or downregulated after neomycin injury in NLPs. Lastly, we constructed a protein-protein interaction network to show the interaction and connections of genes that are differentially expressed in NLPs and ULPs. This study has identified the genes that might regulate the proliferation and HC regeneration of Lgr5+ progenitors after neomycin injury, and investigations into the roles and mechanisms of these genes in the cochlea should be performed in the future to identify potential therapeutic targets for HC regeneration.
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Affiliation(s)
- Shasha Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China.,Research Institute of OtolaryngologyNanjing, China.,Co-innovation Center of Neuroregeneration, Nantong UniversityNantong, China
| | - Yuan Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China
| | - Pengfei Yu
- Bioinformatics Department, Admera Health LLCSouth Plainfield, NJ, United States
| | - Yao Hu
- School of Pharmacy, Institute for Stem Cell and Neural Regeneration, Nanjing Medical UniversityNanjing, China
| | - Han Zhou
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjing, China
| | - Lingna Guo
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China
| | - Xiaochen Xu
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China
| | - Xiaocheng Zhu
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjing, China
| | - Muhammad Waqas
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China.,Department of Biotechnology, Federal Urdu University of Arts, Science and TechnologyKarachi, Pakistan
| | - Jieyu Qi
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China
| | - Xiaoli Zhang
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjing, China
| | - Yan Liu
- School of Pharmacy, Institute for Stem Cell and Neural Regeneration, Nanjing Medical UniversityNanjing, China
| | - Fangyi Chen
- Department of Biomedical Engineering, Southern University of Science and TechnologyShenzhen, China
| | - Mingliang Tang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China
| | - Xiaoyun Qian
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjing, China
| | - Haibo Shi
- Department of Otorhinolaryngology Head and Neck Surgery, The Sixth People's Hospital Affiliated to Shanghai Jiao Tong UniversityShanghai, China
| | - Xia Gao
- Research Institute of OtolaryngologyNanjing, China.,Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjing, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China.,Research Institute of OtolaryngologyNanjing, China.,Co-innovation Center of Neuroregeneration, Nantong UniversityNantong, China
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46
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Doetzlhofer A, Avraham KB. Insights into inner ear-specific gene regulation: Epigenetics and non-coding RNAs in inner ear development and regeneration. Semin Cell Dev Biol 2017; 65:69-79. [PMID: 27836639 PMCID: PMC5512292 DOI: 10.1016/j.semcdb.2016.11.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/14/2016] [Accepted: 11/03/2016] [Indexed: 12/12/2022]
Abstract
The vertebrate inner ear houses highly specialized sensory organs, tuned to detect and encode sound, head motion and gravity. Gene expression programs under the control of transcription factors orchestrate the formation and specialization of the non-sensory inner ear labyrinth and its sensory constituents. More recently, epigenetic factors and non-coding RNAs emerged as an additional layer of gene regulation, both in inner ear development and disease. In this review, we provide an overview on how epigenetic modifications and non-coding RNAs, in particular microRNAs (miRNAs), influence gene expression and summarize recent discoveries that highlight their critical role in the proper formation of the inner ear labyrinth and its sensory organs. Finally, we discuss recent insights into how epigenetic factors and miRNAs may facilitate, or in the case of mammals, restrict inner ear sensory hair cell regeneration.
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Affiliation(s)
- Angelika Doetzlhofer
- The Solomon H. Snyder Department of Neuroscience, the Center for Sensory Biology, the Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel.
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Mittal R, Debs LH, Nguyen D, Patel AP, Grati M, Mittal J, Yan D, Eshraghi AA, Liu XZ. Signaling in the Auditory System: Implications in Hair Cell Regeneration and Hearing Function. J Cell Physiol 2017; 232:2710-2721. [DOI: 10.1002/jcp.25695] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 11/18/2016] [Indexed: 02/06/2023]
Affiliation(s)
- Rahul Mittal
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Luca H. Debs
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Desiree Nguyen
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Amit P. Patel
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - M'hamed Grati
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Jeenu Mittal
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Denise Yan
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Adrien A. Eshraghi
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Xue Zhong Liu
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
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Rask-Andersen H, Li H, Löwenheim H, Müller M, Pfaller K, Schrott-Fischer A, Glueckert R. Supernumerary human hair cells-signs of regeneration or impaired development? A field emission scanning electron microscopy study. Ups J Med Sci 2017; 122:11-19. [PMID: 28145795 PMCID: PMC5361427 DOI: 10.1080/03009734.2016.1271843] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Current attempts to regenerate cochlear sensorineural structures motivate further inspection of the human organ of hearing. Here, we analyzed the supernumerary inner hair cell (sIHC), a possible sign of regeneration and cell replacement. METHODS Human cochleae were studied using field emission scanning electron microscopy (FESEM; maximum resolution 2 nm) obtained from individuals aged 44, 48, and 58 years with normal sensorineural pure-tone average (PTA) thresholds (PTA <20 dB). The wasted tissue was harvested during trans-cochlear approaches and immediately fixed for ultrastructural analysis. RESULTS All specimens exhibited sIHCs at all turns except at the extreme lower basal turn. In one specimen, it was possible to image and count the inner hair cells (IHCs) along the cochlea representing the 0.2 kHz-8 kHz region according to the Greenwood place/frequency scale. In a region with 2,321 IHCs, there were 120 scattered one-cell losses or 'gaps' (5%). Forty-two sIHCs were present facing the modiolus. Thirty-eight percent of the sIHCs were located near a 'gap' in the IHC row (±6 IHCs). CONCLUSIONS The prevalence of ectopic inner hair cells was higher than expected. The morphology and placement could reflect a certain ongoing regeneration. Further molecular studies are needed to verify if the regenerative capacity of the human auditory periphery might have been underestimated.
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Affiliation(s)
- Helge Rask-Andersen
- Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
- Department of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
- CONTACT Helge Rask-Andersen Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, SE-751 85, Uppsala, Sweden
| | - Hao Li
- Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
- Department of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
| | - Hubert Löwenheim
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
- Medical Campus University of Oldenburg School of Medicine and Health Sciences, European Medical School, Oldenburg, Germany
- Research Center of Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Marcus Müller
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
- Medical Campus University of Oldenburg School of Medicine and Health Sciences, European Medical School, Oldenburg, Germany
- Research Center of Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Kristian Pfaller
- Cluster of Excellence Hearing4all, University of Oldenburg, Oldenburg, Germany
| | - Annelies Schrott-Fischer
- Department of Histology and Molecular Cell Biology, Institute of Anatomy and Histology, Medical University of Innsbruck, Innsbruck, Austria
| | - Rudolf Glueckert
- Department of Histology and Molecular Cell Biology, Institute of Anatomy and Histology, Medical University of Innsbruck, Innsbruck, Austria
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Kelley MW, Stone JS. Development and Regeneration of Sensory Hair Cells. AUDITORY DEVELOPMENT AND PLASTICITY 2017. [DOI: 10.1007/978-3-319-21530-3_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Zheng F, Zuo J. Cochlear hair cell regeneration after noise-induced hearing loss: Does regeneration follow development? Hear Res 2016; 349:182-196. [PMID: 28034617 DOI: 10.1016/j.heares.2016.12.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 11/22/2016] [Accepted: 12/20/2016] [Indexed: 12/14/2022]
Abstract
Noise-induced hearing loss (NIHL) affects a large number of military personnel and civilians. Regenerating inner-ear cochlear hair cells (HCs) is a promising strategy to restore hearing after NIHL. In this review, we first summarize recent transcriptome profile analysis of zebrafish lateral lines and chick utricles where spontaneous HC regeneration occurs after HC damage. We then discuss recent studies in other mammalian regenerative systems such as pancreas, heart and central nervous system. Both spontaneous and forced HC regeneration occurs in mammalian cochleae in vivo involving proliferation and direct lineage conversion. However, both processes are inefficient and incomplete, and decline with age. For direct lineage conversion in vivo in cochleae and in other systems, further improvement requires multiple factors, including transcription, epigenetic and trophic factors, with appropriate stoichiometry in appropriate architectural niche. Increasing evidence from other systems indicates that the molecular paths of direct lineage conversion may be different from those of normal developmental lineages. We therefore hypothesize that HC regeneration does not have to follow HC development and that epigenetic memory of supporting cells influences the HC regeneration, which may be a key to successful cochlear HC regeneration. Finally, we discuss recent efforts in viral gene therapy and drug discovery for HC regeneration. We hope that combination therapy targeting multiple factors and epigenetic signaling pathways will provide promising avenues for HC regeneration in humans with NIHL and other types of hearing loss.
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Affiliation(s)
- Fei Zheng
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, MS 322, Memphis, TN 38105, United States.
| | - Jian Zuo
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, MS 322, Memphis, TN 38105, United States.
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