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Zhang L, Chen X, Wang X, Zhou Y, Fang Y, Gu X, Zhang Z, Sun Q, Li N, Xu L, Tan F, Chai R, Qi J. AAV-mediated Gene Cocktails Enhance Supporting Cell Reprogramming and Hair Cell Regeneration. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2304551. [PMID: 38810137 DOI: 10.1002/advs.202304551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 05/02/2024] [Indexed: 05/31/2024]
Abstract
Mammalian cochlear hair cells (HCs) are essential for hearing, and damage to HCs results in severe hearing impairment. Damaged HCs can be regenerated by neighboring supporting cells (SCs), thus the functional regeneration of HCs is the main goal for the restoration of auditory function in vivo. Here, cochlear SC trans-differentiation into outer and inner HC by the induced expression of the key transcription factors Atoh1 and its co-regulators Gfi1, Pou4f3, and Six1 (GPAS), which are necessary for SCs that are destined for HC development and maturation via the AAV-ie targeting the inner ear stem cells are successfully achieved. Single-cell nuclear sequencing and lineaging tracing results showed that the majority of new Atoh1-derived HCs are in a state of initiating differentiation, while GP (Gfi1, Pou4f3) and GPS (Gfi1, Pou4f3, and Six1) enhanced the Atoh1-induced new HCs into inner and outer HCs. Moreover, the patch-clamp analysis indicated that newborn inner HCs induced by GPAS forced expression have similar electrophysiological characteristics to those of native inner HCs. Also, GPAS can induce HC regeneration in the HC-damaged mice model. In summary, the study demonstrates that AAV-mediated co-regulation of multiple genes, such as GPAS, is an effective means to achieve functional HC regeneration in the mouse cochlea.
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Affiliation(s)
- Liyan Zhang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Xin Chen
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Xinlin Wang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Yinyi Zhou
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Yuan Fang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Xingliang Gu
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Ziyu Zhang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Qiuhan Sun
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Nianci Li
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Lei Xu
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Shandong University, Jinan, 250022, China
- Shandong Institute of Otorhinolaryngology, Jinan, 250022, China
| | - Fangzhi Tan
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Renjie Chai
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, 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
- Department of Neurology, Aerospace Center Hospital, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
- Department of Otolaryngology-Head and Neck Surgery, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China
- Southeast University Shenzhen Research Institute, Shenzhen, 518063, China
| | - Jieyu Qi
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, 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
- Department of Neurology, Aerospace Center Hospital, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
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Veithen M, Huyghe A, Van Den Ackerveken P, Fukada SI, Kokubo H, Breuskin I, Nguyen L, Delacroix L, Malgrange B. Sox9 Inhibits Cochlear Hair Cell Fate by Upregulating Hey1 and HeyL Antagonists of Atoh1. Cells 2023; 12:2148. [PMID: 37681879 PMCID: PMC10486728 DOI: 10.3390/cells12172148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 09/09/2023] Open
Abstract
It is widely accepted that cell fate determination in the cochlea is tightly controlled by different transcription factors (TFs) that remain to be fully defined. Here, we show that Sox9, initially expressed in the entire sensory epithelium of the cochlea, progressively disappears from differentiating hair cells (HCs) and is finally restricted to supporting cells (SCs). By performing ex vivo electroporation of E13.5-E14.5 cochleae, we demonstrate that maintenance of Sox9 expression in the progenitors committed to HC fate blocks their differentiation, even if co-expressed with Atoh1, a transcription factor necessary and sufficient to form HC. Sox9 inhibits Atoh1 transcriptional activity by upregulating Hey1 and HeyL antagonists, and genetic ablation of these genes induces extra HCs along the cochlea. Although Sox9 suppression from sensory progenitors ex vivo leads to a modest increase in the number of HCs, it is not sufficient in vivo to induce supernumerary HC production in an inducible Sox9 knockout model. Taken together, these data show that Sox9 is downregulated from nascent HCs to allow the unfolding of their differentiation program. This may be critical for future strategies to promote fully mature HC formation in regeneration approaches.
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Affiliation(s)
- Mona Veithen
- Laboratory of Developmental Neurobiology, GIGA-Neurosciences, University of Liege, 4000 Liege, Belgium; (M.V.); (A.H.); (P.V.D.A.); (I.B.); (L.D.)
| | - Aurélia Huyghe
- Laboratory of Developmental Neurobiology, GIGA-Neurosciences, University of Liege, 4000 Liege, Belgium; (M.V.); (A.H.); (P.V.D.A.); (I.B.); (L.D.)
| | - Priscilla Van Den Ackerveken
- Laboratory of Developmental Neurobiology, GIGA-Neurosciences, University of Liege, 4000 Liege, Belgium; (M.V.); (A.H.); (P.V.D.A.); (I.B.); (L.D.)
| | - So-ichiro Fukada
- Laboratory of Stem Cell Regeneration and Adaptation, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan;
| | - Hiroki Kokubo
- Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan;
| | - Ingrid Breuskin
- Laboratory of Developmental Neurobiology, GIGA-Neurosciences, University of Liege, 4000 Liege, Belgium; (M.V.); (A.H.); (P.V.D.A.); (I.B.); (L.D.)
| | - Laurent Nguyen
- Laboratory of Molecular Regulation of Neurogenesis, GIGA-Neurosciences, University of Liege, 4000 Liege, Belgium;
| | - Laurence Delacroix
- Laboratory of Developmental Neurobiology, GIGA-Neurosciences, University of Liege, 4000 Liege, Belgium; (M.V.); (A.H.); (P.V.D.A.); (I.B.); (L.D.)
| | - Brigitte Malgrange
- Laboratory of Developmental Neurobiology, GIGA-Neurosciences, University of Liege, 4000 Liege, Belgium; (M.V.); (A.H.); (P.V.D.A.); (I.B.); (L.D.)
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Wang X, Llamas J, Trecek T, Shi T, Tao L, Makmura W, Crump JG, Segil N, Gnedeva K. SoxC transcription factors shape the epigenetic landscape to establish competence for sensory differentiation in the mammalian organ of Corti. Proc Natl Acad Sci U S A 2023; 120:e2301301120. [PMID: 37585469 PMCID: PMC10450657 DOI: 10.1073/pnas.2301301120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 06/28/2023] [Indexed: 08/18/2023] Open
Abstract
The auditory organ of Corti is comprised of only two major cell types-the mechanosensory hair cells and their associated supporting cells-both specified from a single pool of prosensory progenitors in the cochlear duct. Here, we show that competence to respond to Atoh1, a transcriptional master regulator necessary and sufficient for induction of mechanosensory hair cells, is established in the prosensory progenitors between E12.0 and 13.5. The transition to the competent state is rapid and is associated with extensive remodeling of the epigenetic landscape controlled by the SoxC group of transcription factors. Conditional loss of Sox4 and Sox11-the two homologous family members transiently expressed in the inner ear at the time of competence establishment-blocks the ability of prosensory progenitors to differentiate as hair cells. Mechanistically, we show that Sox4 binds to and establishes accessibility of early sensory lineage-specific regulatory elements, including ones associated with Atoh1 and its direct downstream targets. Consistent with these observations, overexpression of Sox4 or Sox11 prior to developmental establishment of competence precociously induces hair cell differentiation in the cochlear progenitors. Further, reintroducing Sox4 or Sox11 expression restores the ability of postnatal supporting cells to differentiate as hair cells in vitro and in vivo. Our findings demonstrate the pivotal role of SoxC family members as agents of epigenetic and transcriptional changes necessary for establishing competence for sensory receptor differentiation in the inner ear.
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Affiliation(s)
- Xizi Wang
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Juan Llamas
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Talon Trecek
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Tuo Shi
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Litao Tao
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Welly Makmura
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - J. Gage Crump
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Neil Segil
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Ksenia Gnedeva
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
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4
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Reagor CC, Velez-Angel N, Hudspeth AJ. Depicting pseudotime-lagged causality across single-cell trajectories for accurate gene-regulatory inference. PNAS NEXUS 2023; 2:pgad113. [PMID: 37113980 PMCID: PMC10129065 DOI: 10.1093/pnasnexus/pgad113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 03/21/2023] [Accepted: 03/23/2023] [Indexed: 04/29/2023]
Abstract
Identifying the causal interactions in gene-regulatory networks requires an accurate understanding of the time-lagged relationships between transcription factors and their target genes. Here we describe DELAY (short for Depicting Lagged Causality), a convolutional neural network for the inference of gene-regulatory relationships across pseudotime-ordered single-cell trajectories. We show that combining supervised deep learning with joint probability matrices of pseudotime-lagged trajectories allows the network to overcome important limitations of ordinary Granger causality-based methods, for example, the inability to infer cyclic relationships such as feedback loops. Our network outperforms several common methods for inferring gene regulation and, when given partial ground-truth labels, predicts novel regulatory networks from single-cell RNA sequencing (scRNA-seq) and single-cell ATAC sequencing (scATAC-seq) data sets. To validate this approach, we used DELAY to identify important genes and modules in the regulatory network of auditory hair cells, as well as likely DNA-binding partners for two hair cell cofactors (Hist1h1c and Ccnd1) and a novel binding sequence for the hair cell-specific transcription factor Fiz1. We provide an easy-to-use implementation of DELAY under an open-source license at https://github.com/calebclayreagor/DELAY.
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Affiliation(s)
| | - Nicolas Velez-Angel
- Howard Hughes Medical Institute and Laboratory of Sensory Neuroscience, The Rockefeller University, New York, NY 10065, USA
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5
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Future Pharmacotherapy for Sensorineural Hearing Loss by Protection and Regeneration of Auditory Hair Cells. Pharmaceutics 2023; 15:pharmaceutics15030777. [PMID: 36986638 PMCID: PMC10054686 DOI: 10.3390/pharmaceutics15030777] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 02/14/2023] [Accepted: 02/24/2023] [Indexed: 03/03/2023] Open
Abstract
Sensorineural hearing loss has been a global burden of diseases for decades. However, according to recent progress in experimental studies on hair cell regeneration and protection, clinical trials of pharmacotherapy for sensorineural hearing loss have rapidly progressed. In this review, we focus on recent clinical trials for hair cell protection and regeneration and outline mechanisms based on associated experimental studies. Outcomes of recent clinical trials provided valuable data regarding the safety and tolerability of intra-cochlear and intra-tympanic applications as drug delivery methods. Recent findings in molecular mechanisms of hair cell regeneration suggested the realization of regenerative medicine for sensorineural hearing loss in the near future.
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6
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Stepwise fate conversion of supporting cells to sensory hair cells in the chick auditory epithelium. iScience 2023; 26:106046. [PMID: 36818302 PMCID: PMC9932131 DOI: 10.1016/j.isci.2023.106046] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 12/17/2022] [Accepted: 01/20/2023] [Indexed: 01/26/2023] Open
Abstract
In contrast to mammals, the avian cochlea, specifically the basilar papilla, can regenerate sensory hair cells, which involves fate conversion of supporting cells to hair cells. To determine the mechanisms for converting supporting cells to hair cells, we used single-cell RNA sequencing during hair cell regeneration in explant cultures of chick basilar papillae. We identified dynamic changes in the gene expression of supporting cells, and the pseudotime trajectory analysis demonstrated the stepwise fate conversion from supporting cells to hair cells. Initially, supporting cell identity was erased and transition to the precursor state occurred. A subsequent gain in hair cell identity progressed together with downregulation of precursor-state genes. Transforming growth factor β receptor 1-mediated signaling was involved in induction of the initial step, and its inhibition resulted in suppression of hair cell regeneration. Our data provide new insights for understanding fate conversion from supporting cells to hair cells in avian basilar papillae.
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7
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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: 16] [Impact Index Per Article: 8.0] [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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Deletion of the Notch ligand Jagged1 during cochlear maturation leads to inner hair cell defects and hearing loss. Cell Death Dis 2022; 13:971. [PMID: 36400760 PMCID: PMC9674855 DOI: 10.1038/s41419-022-05380-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/25/2022] [Accepted: 10/26/2022] [Indexed: 11/19/2022]
Abstract
The mammalian cochlea is an exceptionally well-organized epithelium composed of hair cells, supporting cells, and innervating neurons. Loss or defects in any of these cell types, particularly the specialized sensory hair cells, leads to deafness. The Notch pathway is known to play a critical role in the decision to become either a hair cell or a supporting cell during embryogenesis; however, little is known about how Notch functions later during cochlear maturation. Uniquely amongst Notch ligands, Jagged1 (JAG1) is localized to supporting cells during cell fate acquisition and continues to be expressed into adulthood. Here, we demonstrate that JAG1 in maturing cochlear supporting cells is essential for normal cochlear function. Specifically, we show that deletion of JAG1 during cochlear maturation disrupts the inner hair cell pathway and leads to a type of deafness clinically similar to auditory neuropathy. Common pathologies associated with disruptions in inner hair cell function, including loss of hair cells, synapses, or auditory neurons, were not observed in JAG1 mutant cochleae. Instead, RNA-seq analysis of JAG1-deficient cochleae identified dysregulation of the Rho GTPase pathway, known to be involved in stereocilia development and maintenance. Interestingly, the overexpression of one of the altered genes, Diaph3, is responsible for autosomal dominant auditory neuropathy-1 (AUNA1) in humans and mice, and is associated with defects in the inner hair cell stereocilia. Strikingly, ultrastructural analyses of JAG1-deleted cochleae revealed stereocilia defects in inner hair cells, including fused and elongated bundles, that were similar to those stereocilia defects reported in AUNA1 mice. Taken together, these data indicate a novel role for Notch signaling in normal hearing development through maintaining stereocilia integrity of the inner hair cells during cochlear maturation.
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Tao L, Segil N. CDK2 regulates aminoglycoside-induced hair cell death through modulating c-Jun activity: Inhibiting CDK2 to preserve hearing. Front Mol Neurosci 2022; 15:1013383. [PMID: 36311033 PMCID: PMC9606710 DOI: 10.3389/fnmol.2022.1013383] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 09/27/2022] [Indexed: 11/13/2022] Open
Abstract
Sensory hair cell death caused by the ototoxic side effects of many clinically used drugs leads to permanent sensorineural hearing loss in patients. Aminoglycoside antibiotics are widely used and well-known for their ototoxicity, but the molecular mechanisms of aminoglycoside-induced hair cell death are not well understood. This creates challenges in our attempts to alleviate or prevent such adverse side effects. Here, we report a regulatory role of CDK2 in aminoglycoside-induced hair cell death. Utilizing organotypic cultures of cochleae from neonatal mice, we show that blocking CDK2 activity by either pharmaceutical inhibition or by Cdk2 gene knockout protects hair cells against the ototoxicity of gentamicin—one of the most commonly used aminoglycoside antibiotics—by interfering with intrinsic programmed cell death processes. Specifically, we show that CDK2 inhibition delays the collapse of mitochondria and the activation of a caspase cascade. Furthermore, at the molecular level, inhibition of CDK2 activity influences proapoptotic JNK signaling by reducing the protein level of c-Jun and suppressing the gentamicin-induced upregulation of c-Jun target genes Jun and Bim. Our in vivo studies reveal that Cdk2 gene knockout animals are significantly less sensitive to gentamicin ototoxicity compared to wild-type littermates. Altogether, our work ascertains the non-cell cycle role of CDK2 in regulating aminoglycoside-induced hair cell apoptosis and sheds lights on new potential strategies for hearing protection against ototoxicity.
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Affiliation(s)
- Litao Tao
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
- USC Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
- *Correspondence: Litao Tao,
| | - Neil Segil
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
- USC Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
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An X, Wang Y, Han B, Hong L, Zha D, Han Y. Expression and distribution of Nob1 in the developing rat cochleae. Gene Expr Patterns 2022; 44:119235. [DOI: 10.1016/j.gep.2022.119235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/21/2022] [Accepted: 03/04/2022] [Indexed: 11/04/2022]
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Langlie J, Finberg A, Bencie NB, Mittal J, Omidian H, Omidi Y, Mittal R, Eshraghi AA. Recent advancements in cell-based models for auditory disorders. BIOIMPACTS 2022; 12:155-169. [PMID: 35411298 PMCID: PMC8905588 DOI: 10.34172/bi.2022.23900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/09/2021] [Accepted: 11/15/2021] [Indexed: 11/24/2022]
Abstract
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Introduction: Cell-based models play an important role in understanding the pathophysiology and etiology of auditory disorders. For the auditory system, models have primarily focused on restoring inner and outer hair cells. However, they have largely underrepresented the surrounding structures and cells that support the function of the hair cells.
Methods: In this article, we will review recent advancements in the evolution of cell-based models of auditory disorders in their progression towards three dimensional (3D) models and organoids that more closely mimic the pathophysiology in vivo.
Results: With the elucidation of the molecular targets and transcription factors required to generate diverse cell lines of the components of inner ear, research is starting to progress from two dimensional (2D) models to a greater 3D approach. Of note, the 3D models of the inner ear, including organoids, are relatively new and emerging in the field. As 3D models of the inner ear continue to evolve in complexity, their role in modeling disease will grow as they bridge the gap between cell culture and in vivo models.
Conclusion: Using 3D cell models to understand the etiology and molecular mechanisms underlying auditory disorders holds great potential for developing more targeted and effective novel therapeutics.
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Affiliation(s)
- Jake Langlie
- Department of Otolaryngology, Cochlear Implant and Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Ariel Finberg
- Department of Otolaryngology, Cochlear Implant and Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Nathalie B. Bencie
- Department of Otolaryngology, Cochlear Implant and Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Jeenu Mittal
- Department of Otolaryngology, Cochlear Implant and Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Hossein Omidian
- Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL 33328, USA
| | - Yadollah Omidi
- Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL 33328, USA
| | - Rahul Mittal
- Department of Otolaryngology, Cochlear Implant and Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Adrien A. Eshraghi
- Department of Otolaryngology, Cochlear Implant and Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, Florida, USA
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA
- Department of Biomedical Engineering, University of Miami, Coral Gables, Florida, USA
- Department of Pediatrics, University of Miami Miller School of Medicine, Miami, Florida, USA
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12
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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: 3] [Impact Index Per Article: 1.0] [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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13
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Sun S, Li S, Luo Z, Ren M, He S, Wang G, Liu Z. Dual expression of Atoh1 and Ikzf2 promotes transformation of adult cochlear supporting cells into outer hair cells. eLife 2021; 10:66547. [PMID: 34477109 PMCID: PMC8439656 DOI: 10.7554/elife.66547] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 09/02/2021] [Indexed: 12/24/2022] Open
Abstract
Mammalian cochlear outer hair cells (OHCs) are essential for hearing. Severe hearing impairment follows OHC degeneration. Previous attempts at regenerating new OHCs from cochlear supporting cells (SCs) have been unsuccessful, notably lacking expression of the key OHC motor protein, Prestin. Thus, regeneration of Prestin+ OHCs represents a barrier to restore auditory function in vivo. Here, we reported the successful in vivo conversion of adult mouse cochlear SCs into Prestin+ OHC-like cells through the concurrent induction of two key transcriptional factors known to be necessary for OHC development: Atoh1 and Ikzf2. Single-cell RNA sequencing revealed the upregulation of 729 OHC genes and downregulation of 331 SC genes in OHC-like cells. The resulting differentiation status of these OHC-like cells was much more advanced than previously achieved. This study thus established an efficient approach to induce the regeneration of Prestin+ OHCs, paving the way for in vivo cochlear repair via SC transdifferentiation.
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Affiliation(s)
- Suhong Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shuting Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhengnan Luo
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Minhui Ren
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shunji He
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Guangqin Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhiyong Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
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14
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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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15
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POU4F3 pioneer activity enables ATOH1 to drive diverse mechanoreceptor differentiation through a feed-forward epigenetic mechanism. Proc Natl Acad Sci U S A 2021; 118:2105137118. [PMID: 34266958 DOI: 10.1073/pnas.2105137118] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During embryonic development, hierarchical cascades of transcription factors interact with lineage-specific chromatin structures to control the sequential steps in the differentiation of specialized cell types. While examples of transcription factor cascades have been well documented, the mechanisms underlying developmental changes in accessibility of cell type-specific enhancers remain poorly understood. Here, we show that the transcriptional "master regulator" ATOH1-which is necessary for the differentiation of two distinct mechanoreceptor cell types, hair cells in the inner ear and Merkel cells of the epidermis-is unable to access much of its target enhancer network in the progenitor populations of either cell type when it first appears, imposing a block to further differentiation. This block is overcome by a feed-forward mechanism in which ATOH1 first stimulates expression of POU4F3, which subsequently acts as a pioneer factor to provide access to closed ATOH1 enhancers, allowing hair cell and Merkel cell differentiation to proceed. Our analysis also indicates the presence of both shared and divergent ATOH1/POU4F3-dependent enhancer networks in hair cells and Merkel cells. These cells share a deep developmental lineage relationship, deriving from their common epidermal origin, and suggesting that this feed-forward mechanism preceded the evolutionary divergence of these very different mechanoreceptive cell types.
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16
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Key Signaling Pathways Regulate the Development and Survival of Auditory Hair Cells. Neural Plast 2021; 2021:5522717. [PMID: 34194486 PMCID: PMC8214483 DOI: 10.1155/2021/5522717] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/01/2021] [Accepted: 05/31/2021] [Indexed: 01/16/2023] Open
Abstract
The loss of auditory sensory hair cells (HCs) is the most common cause of sensorineural hearing loss (SNHL). As the main sound transmission structure in the cochlea, it is necessary to maintain the normal shape and survival of HCs. In this review, we described and summarized the signaling pathways that regulate the development and survival of auditory HCs in SNHL. The role of the mitogen-activated protein kinase (MAPK), phosphoinositide-3 kinase/protein kinase B (PI3K/Akt), Notch/Wnt/Atoh1, calcium channels, and oxidative stress/reactive oxygen species (ROS) signaling pathways are the most relevant. The molecular interactions of these signaling pathways play an important role in the survival of HCs, which may provide a theoretical basis and possible therapeutic interventions for the treatment of hearing loss.
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17
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Karimi-Boroujeni M, Zahedi-Amiri A, Coombs KM. Embryonic Origins of Virus-Induced Hearing Loss: Overview of Molecular Etiology. Viruses 2021; 13:71. [PMID: 33419104 PMCID: PMC7825458 DOI: 10.3390/v13010071] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 12/19/2022] Open
Abstract
Hearing loss, one of the most prevalent chronic health conditions, affects around half a billion people worldwide, including 34 million children. The World Health Organization estimates that the prevalence of disabling hearing loss will increase to over 900 million people by 2050. Many cases of congenital hearing loss are triggered by viral infections during different stages of pregnancy. However, the molecular mechanisms by which viruses induce hearing loss are not sufficiently explored, especially cases that are of embryonic origins. The present review first describes the cellular and molecular characteristics of the auditory system development at early stages of embryogenesis. These developmental hallmarks, which initiate upon axial specification of the otic placode as the primary root of the inner ear morphogenesis, involve the stage-specific regulation of several molecules and pathways, such as retinoic acid signaling, Sonic hedgehog, and Wnt. Different RNA and DNA viruses contributing to congenital and acquired hearing loss are then discussed in terms of their potential effects on the expression of molecules that control the formation of the auditory and vestibular compartments following otic vesicle differentiation. Among these viruses, cytomegalovirus and herpes simplex virus appear to have the most effect upon initial molecular determinants of inner ear development. Moreover, of the molecules governing the inner ear development at initial stages, SOX2, FGFR3, and CDKN1B are more affected by viruses causing either congenital or acquired hearing loss. Abnormalities in the function or expression of these molecules influence processes like cochlear development and production of inner ear hair and supporting cells. Nevertheless, because most of such virus-host interactions were studied in unrelated tissues, further validations are needed to confirm whether these viruses can mediate the same effects in physiologically relevant models simulating otic vesicle specification and growth.
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Affiliation(s)
- Maryam Karimi-Boroujeni
- School of Rehabilitation Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1H 8M5, Canada;
| | - Ali Zahedi-Amiri
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3E 0J9, Canada;
- Manitoba Centre for Proteomics and Systems Biology, Winnipeg, MB R3E 3P4, Canada
| | - Kevin M. Coombs
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3E 0J9, Canada;
- Manitoba Centre for Proteomics and Systems Biology, Winnipeg, MB R3E 3P4, Canada
- Children’s Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB R3E 3P4, Canada
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18
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Watanabe Y, Seya D, Ihara D, Ishii S, Uemoto T, Kubo A, Arai Y, Isomoto Y, Nakano A, Abe T, Shigeta M, Kawamura T, Saito Y, Ogura T, Nakagawa O. Importance of endothelial Hey1 expression for thoracic great vessel development and its distal enhancer for Notch-dependent endothelial transcription. J Biol Chem 2020; 295:17632-17645. [PMID: 33454003 PMCID: PMC7762959 DOI: 10.1074/jbc.ra120.015003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 10/12/2020] [Indexed: 12/19/2022] Open
Abstract
Thoracic great vessels such as the aorta and subclavian arteries are formed through dynamic remodeling of embryonic pharyngeal arch arteries (PAAs). Previous work has shown that loss of a basic helix-loop-helix transcription factor Hey1 in mice causes abnormal fourth PAA development and lethal great vessel anomalies resembling congenital malformations in humans. However, how Hey1 mediates vascular formation remains unclear. In this study, we revealed that Hey1 in vascular endothelial cells, but not in smooth muscle cells, played essential roles for PAA development and great vessel morphogenesis in mouse embryos. Tek-Cre-mediated Hey1 deletion in endothelial cells affected endothelial tube formation and smooth muscle differentiation in embryonic fourth PAAs and resulted in interruption of the aortic arch and other great vessel malformations. Cell specificity and signal responsiveness of Hey1 expression were controlled through multiple cis-regulatory regions. We found two distal genomic regions that had enhancer activity in endothelial cells and in the pharyngeal epithelium and somites, respectively. The novel endothelial enhancer was conserved across species and was specific to large-caliber arteries. Its transcriptional activity was regulated by Notch signaling in vitro and in vivo, but not by ALK1 signaling and other transcription factors implicated in endothelial cell specificity. The distal endothelial enhancer was not essential for basal Hey1 expression in mouse embryos but may likely serve for Notch-dependent transcriptional control in endothelial cells together with the proximal regulatory region. These findings help in understanding the significance and regulation of endothelial Hey1 as a mediator of multiple signaling pathways in embryonic vascular formation.
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Affiliation(s)
- Yusuke Watanabe
- Department of Molecular Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan; Graduate School of Medical Sciences, Nara Medical University, Kashihara, Nara, Japan.
| | - Daiki Seya
- Department of Molecular Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
| | - Dai Ihara
- Department of Molecular Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan; Laboratory of Stem Cell and Regenerative Medicine, Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Shuhei Ishii
- Department of Molecular Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan; Graduate School of Medical Sciences, Nara Medical University, Kashihara, Nara, Japan
| | - Taiki Uemoto
- Department of Molecular Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan; Graduate School of Medical Sciences, Nara Medical University, Kashihara, Nara, Japan
| | - Atsushi Kubo
- Department of Developmental Neurobiology, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Miyagi, Japan
| | - Yuji Arai
- Department of Molecular Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan; Laboratory of Animal Experiment and Medical Management, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
| | - Yoshie Isomoto
- Laboratory of Animal Experiment and Medical Management, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
| | - Atsushi Nakano
- Laboratory of Animal Experiment and Medical Management, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
| | - Takaya Abe
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Mayo Shigeta
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Teruhisa Kawamura
- Laboratory of Stem Cell and Regenerative Medicine, Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Yoshihiko Saito
- Graduate School of Medical Sciences, Nara Medical University, Kashihara, Nara, Japan; Department of Cardiovascular Medicine, Nara Medical University, Kashihara, Nara, Japan
| | - Toshihiko Ogura
- Department of Developmental Neurobiology, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Miyagi, Japan
| | - Osamu Nakagawa
- Department of Molecular Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan; Graduate School of Medical Sciences, Nara Medical University, Kashihara, Nara, Japan.
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19
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Mittal R, Bencie N, Liu G, Eshraghi N, Nisenbaum E, Blanton SH, Yan D, Mittal J, Dinh CT, Young JI, Gong F, Liu XZ. Recent advancements in understanding the role of epigenetics in the auditory system. Gene 2020; 761:144996. [PMID: 32738421 DOI: 10.1016/j.gene.2020.144996] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/21/2020] [Indexed: 11/19/2022]
Abstract
Sensorineural deafness in mammals is most commonly caused by damage to inner ear sensory epithelia, or hair cells, and can be attributed to genetic and environmental causes. After undergoing trauma, many non-mammalian organisms, including reptiles, birds, and zebrafish, are capable of regenerating damaged hair cells. Mammals, however, are not capable of regenerating damaged inner ear sensory epithelia, so that hair cell damage is permanent and can lead to hearing loss. The field of epigenetics, which is the study of various phenotypic changes caused by modification of genetic expression rather than alteration of DNA sequence, has seen numerous developments in uncovering biological mechanisms of gene expression and creating various medical treatments. However, there is a lack of information on the precise contribution of epigenetic modifications in the auditory system, specifically regarding their correlation with development of inner ear (cochlea) and consequent hearing impairment. Current studies have suggested that epigenetic modifications influence differentiation, development, and protection of auditory hair cells in cochlea, and can lead to hair cell degeneration. The objective of this article is to review the existing literature and discuss the advancements made in understanding epigenetic modifications of inner ear sensory epithelial cells. The analysis of the emerging epigenetic mechanisms related to inner ear sensory epithelial cells development, differentiation, protection, and regeneration will pave the way to develop novel therapeutic strategies for hearing loss.
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Affiliation(s)
- Rahul Mittal
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Nicole Bencie
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - George Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Nicolas Eshraghi
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Eric Nisenbaum
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Susan H Blanton
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA; Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Denise Yan
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jeenu Mittal
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Christine T Dinh
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Juan I Young
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Feng Gong
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Xue Zhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA; Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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20
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Hes5.9 Coordinate FGF and Notch Signaling to Modulate Gastrulation via Regulating Cell Fate Specification and Cell Migration in Xenopus tropicalis. Genes (Basel) 2020; 11:genes11111363. [PMID: 33218193 PMCID: PMC7699193 DOI: 10.3390/genes11111363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/02/2020] [Accepted: 11/13/2020] [Indexed: 01/15/2023] Open
Abstract
Gastrulation drives the establishment of three germ layers and embryonic axes during frog embryonic development. Mesodermal cell fate specification and morphogenetic movements are vital factors coordinating gastrulation, which are regulated by numerous signaling pathways, such as the Wnt (Wingless/Integrated), Notch, and FGF (Fibroblast growth factor) pathways. However, the coordination of the Notch and FGF signaling pathways during gastrulation remains unclear. We identified a novel helix–loop–helix DNA binding domain gene (Hes5.9), which was regulated by the FGF and Notch signaling pathways during gastrulation. Furthermore, gain- and loss-of-function of Hes5.9 led to defective cell migration and disturbed the expression patterns of mesodermal and endodermal marker genes, thus interfering with gastrulation. Collectively, these results suggest that Hes5.9 plays a crucial role in cell fate decisions and cell migration during gastrulation, which is modulated by the FGF and Notch signaling pathways.
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21
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Matsunaga M, Kita T, Yamamoto R, Yamamoto N, Okano T, Omori K, Sakamoto S, Nakagawa T. Initiation of Supporting Cell Activation for Hair Cell Regeneration in the Avian Auditory Epithelium: An Explant Culture Model. Front Cell Neurosci 2020; 14:583994. [PMID: 33281558 PMCID: PMC7688741 DOI: 10.3389/fncel.2020.583994] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 10/14/2020] [Indexed: 01/08/2023] Open
Abstract
Sensorineural hearing loss is a common disability often caused by the loss of sensory hair cells in the cochlea. Hair cell (HCs) regeneration has long been the main target for the development of novel therapeutics for sensorineural hearing loss. In the mammalian cochlea, hair cell regeneration is limited, but the auditory epithelia of non-mammalian organisms retain the capacity for hair cell regeneration. In the avian basilar papilla (BP), supporting cells (SCs), which give rise to regenerated hair cells, are usually quiescent. Hair cell loss induces both direct transdifferentiation and mitotic division of supporting cells. Here, we established an explant culture model for hair cell regeneration in chick basilar papillae and validated it for investigating the initial phase of hair cell regeneration. The histological assessment demonstrated hair cell regeneration via direct transdifferentiation of supporting cells. Labeling with 5-ethynyl-2′-deoxyuridine (EdU) revealed the occurrence of mitotic division in the supporting cells at specific locations in the basilar papillae, while no EdU labeling was observed in newly generated hair cells. RNA sequencing indicated alterations in known signaling pathways associated with hair cell regeneration, consistent with previous findings. Also, unbiased analyses of RNA sequencing data revealed novel genes and signaling pathways that may be related to the induction of supporting cell activation in the chick basilar papillae. These results indicate the advantages of our explant culture model of the chick basilar papillae for exploring the molecular mechanisms of hair cell regeneration.
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Affiliation(s)
- Mami Matsunaga
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tomoko Kita
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Ryosuke Yamamoto
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Norio Yamamoto
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takayuki Okano
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Koichi Omori
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | | | - Takayuki Nakagawa
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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22
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Recent advancements in understanding the role of epigenetics in the auditory system. Gene 2020. [DOI: 10.1016/j.gene.2020.144996
expr 848609818 + 898508594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
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23
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The Notch Ligand Jagged1 Is Required for the Formation, Maintenance, and Survival of Hensen's Cells in the Mouse Cochlea. J Neurosci 2020; 40:9401-9413. [PMID: 33127852 DOI: 10.1523/jneurosci.1192-20.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 10/16/2020] [Accepted: 10/23/2020] [Indexed: 01/09/2023] Open
Abstract
During cochlear development, the Notch ligand JAGGED 1 (JAG1) plays an important role in the specification of the prosensory region, which gives rise to sound-sensing hair cells and neighboring supporting cells (SCs). While JAG1's expression is maintained in SCs through adulthood, the function of JAG1 in SC development is unknown. Here, we demonstrate that JAG1 is essential for the formation and maintenance of Hensen's cells, a highly specialized SC subtype located at the edge of the auditory epithelium. Using Sox2 CreERT2/+::Jag1loxP/loxP mice of both genders, we show that Jag1 deletion at the onset of differentiation, at embryonic day 14.5, disrupted Hensen's cell formation. Similar loss of Hensen's cells was observed when Jag1 was deleted after Hensen's cell formation at postnatal day (P) 0/P1 and fate-mapping analysis revealed that in the absence of Jag1, some Hensen's cells die, but others convert into neighboring Claudius cells. In support of a role for JAG1 in cell survival, genes involved in mitochondrial function and protein synthesis were downregulated in the sensory epithelium of P0 cochlea lacking Jag1 Finally, using Fgfr3-iCreERT2 ::Jag1loxP/loxP mice to delete Jag1 at P0, we observed a similar loss of Hensen's cells and found that adult Jag1 mutant mice have hearing deficits at the low-frequency range.SIGNIFICANCE STATEMENT Hensen's cells play an essential role in the development and homeostasis of the cochlea. Defects in the biophysical or functional properties of Hensen's cells have been linked to auditory dysfunction and hearing loss. Despite their importance, surprisingly little is known about the molecular mechanisms that guide their development. Morphologic and fate-mapping analyses in our study revealed that, in the absence of the Notch ligand JAGGED1, Hensen's cells died or converted into Claudius cells, which are specialized epithelium-like cells outside the sensory epithelium. Confirming a link between JAGGED1 and cell survival, transcriptional profiling showed that JAGGED1 maintains genes critical for mitochondrial function and tissue homeostasis. Finally, auditory phenotyping revealed that JAGGED1's function in supporting cells is necessary for low-frequency hearing.
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White PM. Perspectives on Human Hearing Loss, Cochlear Regeneration, and the Potential for Hearing Restoration Therapies. Brain Sci 2020; 10:brainsci10100756. [PMID: 33092183 PMCID: PMC7589617 DOI: 10.3390/brainsci10100756] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/13/2020] [Accepted: 10/16/2020] [Indexed: 12/23/2022] Open
Abstract
Most adults who acquire hearing loss find it to be a disability that is poorly corrected by current prosthetics. This gap drives current research in cochlear mechanosensory hair cell regeneration and in hearing restoration. Birds and fish can spontaneously regenerate lost hair cells through a process that has become better defined in the last few years. Findings from these studies have informed new research on hair cell regeneration in the mammalian cochlea. Hair cell regeneration is one part of the greater problem of hearing restoration, as hearing loss can stem from a myriad of causes. This review discusses these issues and recent findings, and places them in the greater social context of need and community.
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Affiliation(s)
- Patricia M White
- Department of Neuroscience, Ernest J. Del Monte Institute for Neuroscience, University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY 14642, USA
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25
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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: 30] [Impact Index Per Article: 7.5] [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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Menendez L, Trecek T, Gopalakrishnan S, Tao L, Markowitz AL, Yu HV, Wang X, Llamas J, Huang C, Lee J, Kalluri R, Ichida J, Segil N. Generation of inner ear hair cells by direct lineage conversion of primary somatic cells. eLife 2020; 9:e55249. [PMID: 32602462 PMCID: PMC7326493 DOI: 10.7554/elife.55249] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 05/27/2020] [Indexed: 02/06/2023] Open
Abstract
The mechanoreceptive sensory hair cells in the inner ear are selectively vulnerable to numerous genetic and environmental insults. In mammals, hair cells lack regenerative capacity, and their death leads to permanent hearing loss and vestibular dysfunction. Their paucity and inaccessibility has limited the search for otoprotective and regenerative strategies. Growing hair cells in vitro would provide a route to overcome this experimental bottleneck. We report a combination of four transcription factors (Six1, Atoh1, Pou4f3, and Gfi1) that can convert mouse embryonic fibroblasts, adult tail-tip fibroblasts and postnatal supporting cells into induced hair cell-like cells (iHCs). iHCs exhibit hair cell-like morphology, transcriptomic and epigenetic profiles, electrophysiological properties, mechanosensory channel expression, and vulnerability to ototoxin in a high-content phenotypic screening system. Thus, direct reprogramming provides a platform to identify causes and treatments for hair cell loss, and may help identify future gene therapy approaches for restoring hearing.
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Affiliation(s)
- Louise Menendez
- Department of Stem Cell and Regenerative Medicine, University of Southern CaliforniaLos AngelesUnited States
- Eli and Edythe Broad Center, University of Southern CaliforniaLos AngelesUnited States
- Zilkha Neurogenetic Institute, University of Southern CaliforniaLos AngelesUnited States
| | - Talon Trecek
- Department of Stem Cell and Regenerative Medicine, University of Southern CaliforniaLos AngelesUnited States
- Eli and Edythe Broad Center, University of Southern CaliforniaLos AngelesUnited States
| | - Suhasni Gopalakrishnan
- Department of Stem Cell and Regenerative Medicine, University of Southern CaliforniaLos AngelesUnited States
- Eli and Edythe Broad Center, University of Southern CaliforniaLos AngelesUnited States
- Zilkha Neurogenetic Institute, University of Southern CaliforniaLos AngelesUnited States
| | - Litao Tao
- Department of Stem Cell and Regenerative Medicine, University of Southern CaliforniaLos AngelesUnited States
- Eli and Edythe Broad Center, University of Southern CaliforniaLos AngelesUnited States
| | - Alexander L Markowitz
- Zilkha Neurogenetic Institute, University of Southern CaliforniaLos AngelesUnited States
- USC Caruso Department of Otolaryngology – Head and Neck Surgery, University of Southern CaliforniaLos AngelesUnited States
| | - Haoze V Yu
- Department of Stem Cell and Regenerative Medicine, University of Southern CaliforniaLos AngelesUnited States
- Eli and Edythe Broad Center, University of Southern CaliforniaLos AngelesUnited States
| | - Xizi Wang
- Department of Stem Cell and Regenerative Medicine, University of Southern CaliforniaLos AngelesUnited States
- Eli and Edythe Broad Center, University of Southern CaliforniaLos AngelesUnited States
| | - Juan Llamas
- Department of Stem Cell and Regenerative Medicine, University of Southern CaliforniaLos AngelesUnited States
- Eli and Edythe Broad Center, University of Southern CaliforniaLos AngelesUnited States
| | | | - James Lee
- DRVision TechnologiesBellevueUnited States
| | - Radha Kalluri
- Zilkha Neurogenetic Institute, University of Southern CaliforniaLos AngelesUnited States
- USC Caruso Department of Otolaryngology – Head and Neck Surgery, University of Southern CaliforniaLos AngelesUnited States
| | - Justin Ichida
- Department of Stem Cell and Regenerative Medicine, University of Southern CaliforniaLos AngelesUnited States
- Eli and Edythe Broad Center, University of Southern CaliforniaLos AngelesUnited States
- Zilkha Neurogenetic Institute, University of Southern CaliforniaLos AngelesUnited States
| | - Neil Segil
- Department of Stem Cell and Regenerative Medicine, University of Southern CaliforniaLos AngelesUnited States
- Eli and Edythe Broad Center, University of Southern CaliforniaLos AngelesUnited States
- USC Caruso Department of Otolaryngology – Head and Neck Surgery, University of Southern CaliforniaLos AngelesUnited States
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Abstract
The cochlea, a coiled structure located in the ventral region of the inner ear, acts as the primary structure for the perception of sound. Along the length of the cochlear spiral is the organ of Corti, a highly derived and rigorously patterned sensory epithelium that acts to convert auditory stimuli into neural impulses. The development of the organ of Corti requires a series of inductive events that specify unique cellular characteristics and axial identities along its three major axes. Here, we review recent studies of the cellular and molecular processes regulating several aspects of cochlear development, such as axial patterning, cochlear outgrowth and cellular differentiation. We highlight how the precise coordination of multiple signaling pathways is required for the successful formation of a complete organ of Corti.
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Affiliation(s)
- Elizabeth Carroll Driver
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Matthew W Kelley
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
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28
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Yang LM, Stout L, Rauchman M, Ornitz DM. Analysis of FGF20-regulated genes in organ of Corti progenitors by translating ribosome affinity purification. Dev Dyn 2020; 249:1217-1242. [PMID: 32492250 DOI: 10.1002/dvdy.211] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Understanding the mechanisms that regulate hair cell (HC) differentiation in the organ of Corti (OC) is essential to designing genetic therapies for hearing loss due to HC loss or damage. We have previously identified Fibroblast Growth Factor 20 (FGF20) as having a key role in HC and supporting cell differentiation in the mouse OC. To investigate the genetic landscape regulated by FGF20 signaling in OC progenitors, we employ Translating Ribosome Affinity Purification combined with Next Generation RNA Sequencing (TRAPseq) in the Fgf20 lineage. RESULTS We show that TRAPseq targeting OC progenitors effectively enriched for RNA from this rare cell population. TRAPseq identified differentially expressed genes (DEGs) downstream of FGF20, including Etv4, Etv5, Etv1, Dusp6, Hey1, Hey2, Heyl, Tectb, Fat3, Cpxm2, Sall1, Sall3, and cell cycle regulators such as Cdc20. Analysis of Cdc20 conditional-null mice identified decreased cochlea length, while analysis of Sall1-null and Sall1-ΔZn2-10 mice, which harbor a mutation that causes Townes-Brocks syndrome, identified a decrease in outer hair cell number. CONCLUSIONS We present two datasets: genes with enriched expression in OC progenitors, and DEGs downstream of FGF20 in the embryonic day 14.5 cochlea. We validate select DEGs via in situ hybridization and in vivo functional studies in mice.
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Affiliation(s)
- Lu M Yang
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Lisa Stout
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael Rauchman
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - David M Ornitz
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, USA
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Notch3 signalling and vascular remodelling in pulmonary arterial hypertension. Clin Sci (Lond) 2020; 133:2481-2498. [PMID: 31868216 PMCID: PMC6928565 DOI: 10.1042/cs20190835] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 11/27/2019] [Accepted: 12/11/2019] [Indexed: 02/07/2023]
Abstract
Notch signalling is critically involved in vascular morphogenesis and function. Four Notch isoforms (Notch1–4) regulating diverse cellular processes have been identified. Of these, Notch3 is expressed almost exclusively in vascular smooth muscle cells (VSMCs), where it is critically involved in vascular development and differentiation. Under pathological conditions, Notch3 regulates VSMC switching between the contractile and synthetic phenotypes. Abnormal Notch3 signalling plays an important role in vascular remodelling, a hallmark of several cardiovascular diseases, including pulmonary arterial hypertension (PAH). Because of the importance of Notch3 in VSMC (de)differentiation, Notch3 has been implicated in the pathophysiology of pulmonary vascular remodelling in PAH. Here we review the current literature on the role of Notch in VSMC function with a focus on Notch3 signalling in pulmonary artery VSMCs, and discuss potential implications in pulmonary artery remodelling in PAH.
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30
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Ihara D, Watanabe Y, Seya D, Arai Y, Isomoto Y, Nakano A, Kubo A, Ogura T, Kawamura T, Nakagawa O. Expression of Hey2 transcription factor in the early embryonic ventricles is controlled through a distal enhancer by Tbx20 and Gata transcription factors. Dev Biol 2020; 461:124-131. [DOI: 10.1016/j.ydbio.2020.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/01/2020] [Accepted: 02/01/2020] [Indexed: 02/07/2023]
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Wu X, Zou S, Wu F, He Z, Kong W. Role of microRNA in inner ear stem cells and related research progress. AMERICAN JOURNAL OF STEM CELLS 2020; 9:16-24. [PMID: 32419976 PMCID: PMC7218733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/22/2020] [Indexed: 06/11/2023]
Abstract
Deafness is one of the major global health problems that seriously affects the quality of human life. At present, there are no successful treatments for deafness caused by cochlear hair cell (HC) damage. The irreversibility of mammalian hearing impairment is that the inner ear's sensory epithelium cannot repair lost hair cells and neurons through spontaneous regeneration. The goal of stem cell therapy for sensorineural hearing loss is to reconstruct the damaged inner ear structure and achieve functional repair. microRNA (miRNA), as a class of highly conserved endogenous non-coding small RNAs, plays an important role in the development of cochlea and HCs. miRNA also participates in the regulation of stem cell proliferation and differentiation, and plays an important role in the process of regeneration of inner ear HCs, miRNA has a broad application prospect of clinical treatment of hearing loss, which is conducive to solving the medical problem of inner ear HC regeneration.
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Affiliation(s)
- Xia Wu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan 430022, P. R. China
| | - Shengyu Zou
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan 430022, P. R. China
| | - Fan Wu
- Otorhinolaryngology Department, Sun Yat-sen Memorial Hospital, Sun Yat-Sen University107 West Yan Jiang Road, Guangzhou 510120, P. R. China
| | - Zuhong He
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan 430022, P. R. China
| | - Weijia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan 430022, P. R. China
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Brown R, Groves AK. Hear, Hear for Notch: Control of Cell Fates in the Inner Ear by Notch Signaling. Biomolecules 2020; 10:biom10030370. [PMID: 32121147 PMCID: PMC7175228 DOI: 10.3390/biom10030370] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 02/08/2023] Open
Abstract
The vertebrate inner ear is responsible for detecting sound, gravity, and head motion. These mechanical forces are detected by mechanosensitive hair cells, arranged in a series of sensory patches in the vestibular and cochlear regions of the ear. Hair cells form synapses with neurons of the VIIIth cranial ganglion, which convey sound and balance information to the brain. They are surrounded by supporting cells, which nourish and protect the hair cells, and which can serve as a source of stem cells to regenerate hair cells after damage in non-mammalian vertebrates. The Notch signaling pathway plays many roles in the development of the inner ear, from the earliest formation of future inner ear ectoderm on the side of the embryonic head, to regulating the production of supporting cells, hair cells, and the neurons that innervate them. Notch signaling is re-deployed in non-mammalian vertebrates during hair cell regeneration, and attempts have been made to manipulate the Notch pathway to promote hair cell regeneration in mammals. In this review, we summarize the different modes of Notch signaling in inner ear development and regeneration, and describe how they interact with other signaling pathways to orchestrate the fine-grained cellular patterns of the ear.
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Affiliation(s)
- Rogers Brown
- Program in Developmental Biology; Baylor College of Medicine, Houston, TX 77030, USA;
| | - Andrew K. Groves
- Program in Developmental Biology; Baylor College of Medicine, Houston, TX 77030, USA;
- Department of Neuroscience; Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Correspondence: ; Tel.: +1-713-798-8743
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Tambalo M, Anwar M, Ahmed M, Streit A. Enhancer activation by FGF signalling during otic induction. Dev Biol 2020; 457:69-82. [PMID: 31539539 PMCID: PMC6902270 DOI: 10.1016/j.ydbio.2019.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/16/2019] [Accepted: 09/16/2019] [Indexed: 02/07/2023]
Abstract
Vertebrate ear progenitors are induced by fibroblast growth factor signalling, however the molecular mechanisms leading to the coordinate activation of downstream targets are yet to be discovered. The ear, like other sensory placodes, arises from the pre-placodal region at the border of the neural plate. Using a multiplex NanoString approach, we determined the response of these progenitors to FGF signalling by examining the changes of more than 200 transcripts that define the otic and other placodes, neural crest and neural plate territories. This analysis identifies new direct and indirect FGF targets during otic induction. Investigating changes in histone marks by ChIP-seq reveals that FGF exposure of pre-placodal cells leads to rapid deposition of active chromatin marks H3K27ac near FGF-response genes, while H3K27ac is depleted in the vicinity of non-otic genes. Genomic regions that gain H3K27ac act as cis-regulatory elements controlling otic gene expression in time and space and define a unique transcription factor signature likely to control their activity. Finally, we show that in response to FGF signalling the transcription factor dimer AP1 recruits the histone acetyl transferase p300 to selected otic enhancers. Thus, during ear induction FGF signalling modifies the chromatin landscape to promote enhancer activation and chromatin accessibility.
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Affiliation(s)
- Monica Tambalo
- Centre for Craniofacial and Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London, SE1 9RT, UK
| | - Maryam Anwar
- Centre for Craniofacial and Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London, SE1 9RT, UK
| | - Mohi Ahmed
- Centre for Craniofacial and Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London, SE1 9RT, UK
| | - Andrea Streit
- Centre for Craniofacial and Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London, SE1 9RT, UK.
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Notch Signalling: The Multitask Manager of Inner Ear Development and Regeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1218:129-157. [DOI: 10.1007/978-3-030-34436-8_8] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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35
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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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36
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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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37
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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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38
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Munnamalai V, Fekete DM. The acquisition of positional information across the radial axis of the cochlea. Dev Dyn 2019; 249:281-297. [PMID: 31566832 DOI: 10.1002/dvdy.118] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 12/11/2022] Open
Affiliation(s)
- Vidhya Munnamalai
- The Jackson Laboratory Bar Harbor Maine
- Graduate Program of Biomedical Sciences and EngineeringUniversity of Maine Orono Maine
- The Neuroscience ProgramSackler School of Biomedical Sciences, Tufts University Boston Massachusetts
| | - Donna M. Fekete
- Department of Biological SciencesPurdue University West Lafayette Indiana
- Purdue Institute for Integrative Neuroscience West Lafayette Indiana
- Purdue Center for Cancer Research West Lafayette Indiana
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39
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Unidirectional and stage-dependent roles of Notch1 in Wnt-responsive Lgr5 + cells during mouse inner ear development. Front Med 2019; 13:705-712. [PMID: 31598881 DOI: 10.1007/s11684-019-0703-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 06/03/2019] [Indexed: 10/25/2022]
Abstract
Wnt and Notch signaling play crucial roles in the determination of the prosensory domain and in the differentiation of hair cells (HCs) and supporting cells during mouse inner ear development; however, the relationship between the two signaling pathways in the mouse cochlea remains largely unknown. Here, we investigated the interactions between Notch and Wnt signaling on the basis of the bidirectional regulation of Notch1 specifically in Wnt-responsive Lgr5+ progenitors during different cochlear development stages. We found that the downregulation of Notch1 in Lgr5+ cells from embryonic day (E) 14.5 to E18.5 can drive the quiescent Lgr5+ cells to re-enter the cell cycle and differentiate into extra HCs, whereas the upregulation of Notch1 expression did not affect the proliferation or differentiation of otic progenitor cells. No effect was observed on the upregulation or downregulation of Notch1 in Lgr5+ cells from E10.5 to E14.5. We concluded that the roles of Notch1 in Wnt-responsive Lgr5+ cells are unidirectional and stage dependent and Notch1 serves as a negative regulator for Lgr5+ progenitor activation during cochlear differentiation. Our findings improved the understanding of the interactions between Notch and Wnt signaling in cochlear development.
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Flint Brodsly N, Bitman-Lotan E, Boico O, Shafat A, Monastirioti M, Gessler M, Delidakis C, Rincon-Arano H, Orian A. The transcription factor Hey and nuclear lamins specify and maintain cell identity. eLife 2019; 8:44745. [PMID: 31310235 PMCID: PMC6634966 DOI: 10.7554/elife.44745] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 07/03/2019] [Indexed: 12/12/2022] Open
Abstract
The inability of differentiated cells to maintain their identity is a hallmark of age-related diseases. We found that the transcription factor Hey supervises the identity of differentiated enterocytes (ECs) in the adult Drosophila midgut. Lineage tracing established that Hey-deficient ECs are unable to maintain their unique nuclear organization and identity. To supervise cell identity, Hey determines the expression of nuclear lamins, switching from a stem-cell lamin configuration to a differentiated lamin configuration. Moreover, continued Hey expression is required to conserve large-scale nuclear organization. During aging, Hey levels decline, and EC identity and gut homeostasis are impaired, including pathological reprograming and compromised gut integrity. These phenotypes are highly similar to those observed upon acute targeting of Hey or perturbation of lamin expression in ECs in young adults. Indeed, aging phenotypes were suppressed by continued expression of Hey in ECs, suggesting that a Hey-lamin network safeguards nuclear organization and differentiated cell identity.
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Affiliation(s)
- Naama Flint Brodsly
- Rappaport Research Institute and Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Eliya Bitman-Lotan
- Rappaport Research Institute and Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Olga Boico
- Rappaport Research Institute and Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Adi Shafat
- Rappaport Research Institute and Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Maria Monastirioti
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology - Hellas (FORTH), Heraklion, Greece
| | - Manfred Gessler
- Biocenter of Developmental Biochemistry, University of Würzburg, Würzburg, Germany
| | - Christos Delidakis
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology - Hellas (FORTH), Heraklion, Greece
| | - Hector Rincon-Arano
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Amir Orian
- Rappaport Research Institute and Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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Prajapati-DiNubila M, Benito-Gonzalez A, Golden EJ, Zhang S, Doetzlhofer A. A counter gradient of Activin A and follistatin instructs the timing of hair cell differentiation in the murine cochlea. eLife 2019; 8:47613. [PMID: 31187730 PMCID: PMC6561706 DOI: 10.7554/elife.47613] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 05/27/2019] [Indexed: 12/14/2022] Open
Abstract
The mammalian auditory sensory epithelium has one of the most stereotyped cellular patterns known in vertebrates. Mechano-sensory hair cells are arranged in precise rows, with one row of inner and three rows of outer hair cells spanning the length of the spiral-shaped sensory epithelium. Aiding such precise cellular patterning, differentiation of the auditory sensory epithelium is precisely timed and follows a steep longitudinal gradient. The molecular signals that promote auditory sensory differentiation and instruct its graded pattern are largely unknown. Here, we identify Activin A and its antagonist follistatin as key regulators of hair cell differentiation and show, using mouse genetic approaches, that a local gradient of Activin A signaling within the auditory sensory epithelium times the longitudinal gradient of hair cell differentiation. Furthermore, we provide evidence that Activin-type signaling regulates a radial gradient of terminal mitosis within the auditory sensory epithelium, which constitutes a novel mechanism for limiting the number of inner hair cells being produced.
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Affiliation(s)
- Meenakshi Prajapati-DiNubila
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Ana Benito-Gonzalez
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Erin Jennifer Golden
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Shuran Zhang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Angelika Doetzlhofer
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, United States
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42
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Ogier JM, Burt RA, Drury HR, Lim R, Nayagam BA. Organotypic Culture of Neonatal Murine Inner Ear Explants. Front Cell Neurosci 2019; 13:170. [PMID: 31130846 PMCID: PMC6509234 DOI: 10.3389/fncel.2019.00170] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 04/11/2019] [Indexed: 01/08/2023] Open
Abstract
The inner ear is a complex organ containing highly specialised cell types and structures that are critical for sensing sound and movement. In vivo, the inner ear is difficult to study due to the osseous nature of the otic capsule and its encapsulation within an intricate bony labyrinth. As such, mammalian inner ear explants are an invaluable tool for the study and manipulation of the complex intercellular connections, structures, and cell types within this specialised organ. The greatest strength of this technique is that the complete organ of Corti, or peripheral vestibular organs including hair cells, supporting cells and accompanying neurons, is maintained in its in situ form. The greatest weakness of in vitro hair cell preparations is the short time frame in which the explanted tissue remains viable. Yet, cochlear explants have proven to be an excellent experimental model for understanding the fundamental aspects of auditory biology, substantiated by their use for over 40 years. In this protocol, we present a modernised inner ear explant technique that employs organotypic cell culture inserts and serum free media. This approach decreases the likelihood of explant damage by eliminating the need for adhesive substances. Serum free media also restricts excessive cellular outgrowth and inter-experimental variability, both of which are side effects of exogenous serum addition to cell cultures. The protocol described can be applied to culture both cochlear and vestibular explants from various mammals. Example outcomes are demonstrated by immunohistochemistry, hair cell quantification, and electrophysiological recordings to validate the versatility and viability of the protocol.
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Affiliation(s)
- Jacqueline M. Ogier
- Department of Genetics, The Murdoch Children's Research Institute, Parkville, VIC, Australia
- Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia
| | - Rachel A. Burt
- Department of Genetics, The Murdoch Children's Research Institute, Parkville, VIC, Australia
- Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia
- Department of Genetics, The University of Melbourne, Parkville, VIC, Australia
| | - Hannah R. Drury
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia
| | - Rebecca Lim
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia
| | - Bryony A. Nayagam
- Department of Audiology and Speech Pathology, The University of Melbourne, Parkville, VIC, Australia
- The Bionics Institute, East Melbourne, VIC, Australia
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43
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Zhong C, Fu Y, Pan W, Yu J, Wang J. Atoh1 and other related key regulators in the development of auditory sensory epithelium in the mammalian inner ear: function and interplay. Dev Biol 2019; 446:133-141. [DOI: 10.1016/j.ydbio.2018.12.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 12/30/2018] [Accepted: 12/30/2018] [Indexed: 01/08/2023]
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44
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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 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] [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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45
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Defourny J, Peuckert C, Kullander K, Malgrange B. EphA4-ADAM10 Interplay Patterns the Cochlear Sensory Epithelium through Local Disruption of Adherens Junctions. iScience 2018; 11:246-257. [PMID: 30639848 PMCID: PMC6327856 DOI: 10.1016/j.isci.2018.12.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 12/19/2018] [Accepted: 12/20/2018] [Indexed: 12/11/2022] Open
Abstract
The cochlear sensory epithelium contains a functionally important triangular fluid-filled space between adjacent pillar cells referred to as the tunnel of Corti. However, the molecular mechanisms leading to local cell-cell separation during development remain elusive. Here we show that EphA4 associates with ADAM10 to promote the destruction of E-cadherin-based adhesions between adjacent pillar cells. These cells fail to separate from each other, and E-cadherin abnormally persists at the pillar cell junction in EphA4 forward-signaling-deficient mice, as well as in the presence of ADAM10 inhibitor. Using immunolabeling and an in situ proximity ligation assay, we found that EphA4 forms a complex with E-cadherin and its sheddase ADAM10, which could be activated by ephrin-B2 across the pillar cell junction to trigger the cleavage of E-cadherin. Altogether, our findings provide a new molecular insight into the regulation of adherens junctions, which might be extended to a variety of physiological or pathological processes.
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Affiliation(s)
- Jean Defourny
- GIGA-Neurosciences, Unit of Cell and Tissue Biology, University of Liège, C.H.U. B36, 4000 Liège, Belgium; GIGA-Neurosciences, Developmental Neurobiology Unit, University of Liège, C.H.U. B36, 4000 Liège, Belgium
| | - Christiane Peuckert
- Department of Neuroscience, Uppsala University, Box 593, Uppsala 75124, Sweden
| | - Klas Kullander
- Department of Neuroscience, Uppsala University, Box 593, Uppsala 75124, Sweden
| | - Brigitte Malgrange
- GIGA-Neurosciences, Developmental Neurobiology Unit, University of Liège, C.H.U. B36, 4000 Liège, Belgium.
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46
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Gibb N, Lazic S, Yuan X, Deshwar AR, Leslie M, Wilson MD, Scott IC. Hey2 regulates the size of the cardiac progenitor pool during vertebrate heart development. Development 2018; 145:dev.167510. [PMID: 30355727 DOI: 10.1242/dev.167510] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 10/13/2018] [Indexed: 01/04/2023]
Abstract
A key event in heart development is the timely addition of cardiac progenitor cells, defects in which can lead to congenital heart defects. However, how the balance and proportion of progenitor proliferation versus addition to the heart is regulated remains poorly understood. Here, we demonstrate that Hey2 functions to regulate the dynamics of cardiac progenitor addition to the zebrafish heart. We found that the previously noted increase in myocardial cell number found in the absence of Hey2 function was due to a pronounced expansion in the size of the cardiac progenitor pool. Expression analysis and lineage tracing of hey2-expressing cells showed that hey2 is active in cardiac progenitors. Hey2 acted to limit proliferation of cardiac progenitors, prior to heart tube formation. Use of a transplantation approach demonstrated a likely cell-autonomous (in cardiac progenitors) function for Hey2. Taken together, our data suggest a previously unappreciated role for Hey2 in controlling the proliferative capacity of cardiac progenitors, affecting the subsequent contribution of late-differentiating cardiac progenitors to the developing vertebrate heart.
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Affiliation(s)
- Natalie Gibb
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Savo Lazic
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Ontario M5S 1A8, Canada
| | - Xuefei Yuan
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Ontario M5S 1A8, Canada
| | - Ashish R Deshwar
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Ontario M5S 1A8, Canada
| | - Meaghan Leslie
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Ontario M5S 1A8, Canada
| | - Michael D Wilson
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Ontario M5S 1A8, Canada
| | - Ian C Scott
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada .,Department of Molecular Genetics, University of Toronto, Ontario M5S 1A8, Canada.,Ted Rogers Centre for Heart Research, Toronto, Ontario M5G 1M1, Canada.,Heart and Stroke Richard Lewar Centres of Excellence in Cardiovascular Research, Toronto, Ontario M5S 3H2, Canada
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47
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Jahan I, Elliott KL, Fritzsch B. Understanding Molecular Evolution and Development of the Organ of Corti Can Provide Clues for Hearing Restoration. Integr Comp Biol 2018; 58:351-365. [PMID: 29718413 PMCID: PMC6104702 DOI: 10.1093/icb/icy019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The mammalian hearing organ is a stereotyped cellular assembly with orderly innervation: two types of spiral ganglion neurons (SGNs) innervate two types of differentially distributed hair cells (HCs). HCs and SGNs evolved from single neurosensory cells through gene multiplication and diversification. Independent regulation of HCs and neuronal differentiation through expression of basic helix-loop-helix transcription factors (bHLH TFs: Atoh1, Neurog1, Neurod1) led to the evolution of vestibular HC assembly and their unique type of innervation. In ancestral mammals, a vestibular organ was transformed into the organ of Corti (OC) containing a single row of inner HC (IHC), three rows of outer HCs (OHCs), several unique supporting cell types, and a peculiar innervation distribution. Restoring the OC following long-term hearing loss is complicated by the fact that the entire organ is replaced by a flat epithelium and requires reconstructing the organ from uniform undifferentiated cell types, recapitulating both evolution and development. Finding the right sequence of gene activation during development that is useful for regeneration could benefit from an understanding of the OC evolution. Toward this end, we report on Foxg1 and Lmx1a mutants that radically alter the OC cell assembly and its innervation when mutated and may have driven the evolutionary reorganization of the basilar papilla into an OC in ancestral Therapsids. Furthermore, genetically manipulating the level of bHLH TFs changes HC type and distribution and allows inference how transformation of HCs might have happened evolutionarily. We report on how bHLH TFs regulate OHC/IHC and how misexpression (Atoh1-Cre; Atoh1f/kiNeurog1) alters HC fate and supporting cell development. Using mice with altered HC types and distribution, we demonstrate innervation changes driven by HC patterning. Using these insights, we speculate on necessary steps needed to convert a random mixture of post-mitotic precursors into the orderly OC through spatially and temporally regulated critical bHLH genes in the context of other TFs to restore normal innervation patterns.
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Affiliation(s)
- Israt Jahan
- Department of Biology, University of Iowa, 129 East Jefferson, Iowa City, IA 52242, USA
| | - Karen L Elliott
- Department of Biology, University of Iowa, 129 East Jefferson, Iowa City, IA 52242, USA
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, 129 East Jefferson, Iowa City, IA 52242, USA
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48
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Zhang Y, Guo L, Lu X, Cheng C, Sun S, Li W, Zhao L, Lai C, Zhang S, Yu C, Tang M, Chen Y, Chai R, Li H. Characterization of Lgr6+ Cells as an Enriched Population of Hair Cell Progenitors Compared to Lgr5+ Cells for Hair Cell Generation in the Neonatal Mouse Cochlea. Front Mol Neurosci 2018; 11:147. [PMID: 29867341 PMCID: PMC5961437 DOI: 10.3389/fnmol.2018.00147] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 04/12/2018] [Indexed: 12/20/2022] Open
Abstract
Hair cell (HC) loss is irreversible because only very limited HC regeneration has been observed in the adult mammalian cochlea. Wnt/β-catenin signaling regulates prosensory cell proliferation and differentiation during cochlear development, and Wnt activation promotes the proliferation of Lgr5+ cochlear HC progenitors in newborn mice. Similar to Lgr5, Lgr6 is also a Wnt downstream target gene. Lgr6 is reported to be present in adult stem cells in the skin, nail, tongue, lung, and mammary gland, and this protein is very important for adult stem cell maintenance in rapidly proliferating organs. Our previous studies showed that Lgr6+ cells are a subpopulation of Lgr5+ progenitor cells and that both Lgr6+ and Lgr5+ progenitors can generate Myosin7a+ HCs in vitro. Thus we hypothesized that Lgr6+ cells are an enriched population of cochlear progenitor cells. However, the detailed distinctions between the Lgr5+ and Lgr6+ progenitors are unclear. Here, we systematically compared the proliferation, HC differentiation, and detailed transcriptome expression profiles of these two progenitor populations. We found that the same number of isolated Lgr6+ progenitors generated significantly more Myosin7a+ HCs compared to Lgr5+ progenitors; however, Lgr5+ progenitors formed more epithelial colonies and more spheres than Lgr6+ progenitors in vitro. Using RNA-Seq, we compared the transcriptome differences between Lgr5+ and Lgr6+ progenitors and identified a list of significantly differential expressed genes that might regulate the proliferation and differentiation of these HC progenitors, including 4 cell cycle genes, 9 cell signaling pathway genes, and 54 transcription factors. In conclusion, we demonstrate that Lgr6+ progenitors are an enriched population of inner ear progenitors that generate more HCs compared to Lgr5+ progenitors in the newborn mouse cochlea, and the our research provides a series of genes that might regulate the proliferation of progenitors and HC generation.
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Affiliation(s)
- Yanping Zhang
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Luo Guo
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Xiaoling Lu
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Cheng Cheng
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Shan Sun
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Wen Li
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Liping Zhao
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Chuijin Lai
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Shasha Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Chenjie Yu
- Department of Otolaryngology Head and Neck Surgery, Jiangsu Provincial Key Medical Discipline Laboratory, Affiliated Drum Tower Hospital, Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Mingliang Tang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Yan Chen
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China.,Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research, 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, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine, National Health and Family Planning Commission (NHFPC), Shanghai, China.,Shanghai Engineering Research Center of Cochlear Implant, Shanghai, China.,The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China.,Institutes of Biomedical Sciences, Fudan University, Shanghai, China
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49
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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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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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