1
|
Hu Z, Singh A, Bojrab D, Sim N. Insights into the molecular mechanisms regulating mammalian hair cell regeneration. Curr Opin Otolaryngol Head Neck Surg 2021; 29:400-406. [PMID: 34374666 DOI: 10.1097/moo.0000000000000752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
PURPOSE OF REVIEW To give an overview of recent advances in mammalian auditory hair cell regeneration. RECENT FINDINGS Supporting cells act as progenitors to regenerate hair cells in the prehearing mammalian cochlea but not in the mature cochlea. To overcome this developmental obstacle, manipulation of multiple genes and intracellular pathways has been investigated, which has obtained promising data. This review focuses on recent advances in auditory hair cell regeneration, including synergic gene regulation associated with Atoh1 and Notch signaling, epigenetics, and functional recovery of regenerated hair cells. Co-manipulation of genes critical for hair cell development and cell cycle re-entry, including Atoh1, Isl1, Pou4f3, Gata3, Gfi1, P27kip1, RB, Myc, and Notch-signaling genes, has generated hair cell-like cells in the adult cochlea both in vitro and in vivo. The epigenetic mechanism has been studied in hair cell development and regeneration. Regeneration of hair cell function has a very limited progress, which lacks in-vitro and in-vivo electrophysiology data. SUMMARY Regeneration of adult auditory hair cells remains a major challenge. Manipulation of multiple genes and pathways together with epigenetic regulation might potentially regenerate functional hair cells in the adult mammalian cochlea.
Collapse
Affiliation(s)
- Zhengqing Hu
- John D. Dingell VA Medical Center
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit
| | - Aditi Singh
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit
| | - Dennis Bojrab
- Michigan Ear Institute, Farmington Hills, Michigan, USA
| | - Nathan Sim
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit
| |
Collapse
|
2
|
Pisciottano F, Cinalli AR, Stopiello JM, Castagna VC, Elgoyhen AB, Rubinstein M, Gómez-Casati ME, Franchini LF. Inner Ear Genes Underwent Positive Selection and Adaptation in the Mammalian Lineage. Mol Biol Evol 2020; 36:1653-1670. [PMID: 31137036 DOI: 10.1093/molbev/msz077] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The mammalian inner ear possesses functional and morphological innovations that contribute to its unique hearing capacities. The genetic bases underlying the evolution of this mammalian landmark are poorly understood. We propose that the emergence of morphological and functional innovations in the mammalian inner ear could have been driven by adaptive molecular evolution. In this work, we performed a meta-analysis of available inner ear gene expression data sets in order to identify genes that show signatures of adaptive evolution in the mammalian lineage. We analyzed ∼1,300 inner ear expressed genes and found that 13% show signatures of positive selection in the mammalian lineage. Several of these genes are known to play an important function in the inner ear. In addition, we identified that a significant proportion of genes showing signatures of adaptive evolution in mammals have not been previously reported to participate in inner ear development and/or physiology. We focused our analysis in two of these genes: STRIP2 and ABLIM2 by generating null mutant mice and analyzed their auditory function. We found that mice lacking Strip2 displayed a decrease in neural response amplitudes. In addition, we observed a reduction in the number of afferent synapses, suggesting a potential cochlear neuropathy. Thus, this study shows the usefulness of pursuing a high-throughput evolutionary approach followed by functional studies to track down genes that are important for inner ear function. Moreover, this approach sheds light on the genetic bases underlying the evolution of the mammalian inner ear.
Collapse
Affiliation(s)
- Francisco Pisciottano
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Alejandro R Cinalli
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Juan Matías Stopiello
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Valeria C Castagna
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires,Argentina
| | - Ana Belén Elgoyhen
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Marcelo Rubinstein
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Facultad de Ciencias Exactas y Naturales (FCEN), Universidad de Buenos Aires, Buenos Aires,Argentina
| | - María Eugenia Gómez-Casati
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires,Argentina
| | - Lucía F Franchini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| |
Collapse
|
3
|
He Z, Fang Q, Li H, Shao B, Zhang Y, Zhang Y, Han X, Guo R, Cheng C, Guo L, Shi L, Li A, Yu C, Kong W, Zhao C, Gao X, Chai R. The role of FOXG1 in the postnatal development and survival of mouse cochlear hair cells. Neuropharmacology 2018; 144:43-57. [PMID: 30336149 DOI: 10.1016/j.neuropharm.2018.10.021] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 09/30/2018] [Accepted: 10/14/2018] [Indexed: 12/17/2022]
Abstract
The development of therapeutic interventions for hearing loss requires a detailed understanding of the genes and proteins involved in hearing. The FOXG1 protein plays an important role in early neural development and in a variety of neurodevelopmental disorders. Previous studies have shown that there are severe deformities in the inner ear in Foxg1 knockout mice, but due to the postnatal lethality of Foxg1 knockout mice, the role of FOXG1 in hair cell (HC) development and survival during the postnatal period has not been investigated. In this study, we took advantage of transgenic mice that have a specific knockout of Foxg1 in HCs, thus allowing us to explore the role of FOXG1 in postnatal HC development and survival. In the Foxg1 conditional knockout (CKO) HCs, an extra row of HCs appeared in the apical turn of the cochlea and some parts of the middle turn at postnatal day (P)1 and P7; however, these HCs gradually underwent apoptosis, and the HC number was significantly decreased by P21. Auditory brainstem response tests showed that the Foxg1 CKO mice had lost their hearing by P30. The RNA-Seq results and the qPCR verification both showed that the Wnt, Notch, IGF, EGF, and Hippo signaling pathways were down-regulated in the HCs of Foxg1 CKO mice. The significant down-regulation of the Notch signaling pathway might be the reason for the increased numbers of HCs in the cochleae of Foxg1 CKO mice at P1 and P7, while the down-regulation of the Wnt, IGF, and EGF signaling pathways might lead to subsequent HC apoptosis. Together, these results indicate that knockout of Foxg1 induces an extra row of HCs via Notch signaling inhibition and induces subsequent apoptosis of these HCs by inhibiting the Wnt, IGF, and EGF signaling pathways. This study thus provides new evidence for the function and mechanism of FOXG1 in HC development and survival in mice.
Collapse
Affiliation(s)
- Zuhong He
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China; Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Qiaojun Fang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China; Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - He Li
- Department of Otolaryngology-Head and Neck Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Buwei Shao
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China; Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Yuan Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China; Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Yuhua Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China; Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Xiao Han
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of Histology and Embryology, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Rongrong Guo
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China; Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Cheng Cheng
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China; Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Lingna Guo
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China; Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Lusen Shi
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory), Nanjing, 210008, China
| | - Ao Li
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory), Nanjing, 210008, China
| | - Chenjie Yu
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory), Nanjing, 210008, China
| | - Weijia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Chunjie Zhao
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of Histology and Embryology, School of Medicine, Southeast University, Nanjing, 210009, China; Center of Depression, Beijing Institute for Brain Disorders, China.
| | - Xia Gao
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory), Nanjing, 210008, China.
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China; Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China; Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 211189, China; Institute for Stem Cell and Regeneration, Chinese Academy of Science, Beijing, China.
| |
Collapse
|
4
|
Chen Y, Lu X, Guo L, Ni W, Zhang Y, Zhao L, Wu L, Sun S, Zhang S, Tang M, Li W, Chai R, Li H. Hedgehog Signaling Promotes the Proliferation and Subsequent Hair Cell Formation of Progenitor Cells in the Neonatal Mouse Cochlea. Front Mol Neurosci 2017; 10:426. [PMID: 29311816 PMCID: PMC5742997 DOI: 10.3389/fnmol.2017.00426] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 12/06/2017] [Indexed: 12/11/2022] Open
Abstract
Hair cell (HC) loss is the major cause of permanent sensorineural hearing loss in mammals. Unlike lower vertebrates, mammalian cochlear HCs cannot regenerate spontaneously after damage, although the vestibular system does maintain limited HC regeneration capacity. Thus HC regeneration from the damaged sensory epithelium has been one of the main areas of research in the field of hearing restoration. Hedgehog signaling plays important roles during the embryonic development of the inner ear, and it is involved in progenitor cell proliferation and differentiation as well as the cell fate decision. In this study, we show that recombinant Sonic Hedgehog (Shh) protein effectively promotes sphere formation, proliferation, and differentiation of Lgr5+ progenitor cells isolated from the neonatal mouse cochlea. To further explore this, we determined the effect of Hedgehog signaling on cell proliferation and HC regeneration in cultured cochlear explant from transgenic R26-SmoM2 mice that constitutively activate Hedgehog signaling in the supporting cells of the cochlea. Without neomycin treatment, up-regulation of Hedgehog signaling did not significantly promote cell proliferation or new HC formation. However, after injury to the sensory epithelium by neomycin treatment, the over-activation of Hedgehog signaling led to significant supporting cell proliferation and HC regeneration in the cochlear epithelium explants. RNA sequencing and real-time PCR were used to compare the transcripts of the cochleae from control mice and R26-SmoM2 mice, and multiple genes involved in the proliferation and differentiation processes were identified. This study has important implications for the treatment of sensorineural hearing loss by manipulating the Hedgehog signaling pathway.
Collapse
Affiliation(s)
- Yan Chen
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Xiaoling Lu
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Luo Guo
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Wenli Ni
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Yanping Zhang
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Liping Zhao
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Lingjie Wu
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Shan Sun
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Shasha Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Mingliang Tang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Wenyan Li
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), 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 High-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, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China.,Institutes of Biomedical Sciences, Fudan University, Shanghai, China.,The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China.,Shanghai Engineering Research Centre of Cochlear Implant, Shanghai, China
| |
Collapse
|
5
|
Ikeda R, Pak K, Chavez E, Ryan AF. Transcription factors with conserved binding sites near ATOH1 on the POU4F3 gene enhance the induction of cochlear hair cells. Mol Neurobiol 2016; 51:672-84. [PMID: 25015561 DOI: 10.1007/s12035-014-8801-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 06/22/2014] [Indexed: 01/21/2023]
Abstract
Overexpression of the transcription factor (TF) ATOH1 is known to induce the transformation of nonsensory cells in the organ of Corti into hair cells (HCs). Evaluating DNA 5Œ to the coding sequence of the pou4f3 gene, a target of ATOH1 in HCs, we identified in three regions containing clustered binding sites for ATOH1 and several other TFs that are expressed in developing inner ear sensory epithelia at the time of HC specification. These regions and sites are highly conserved across evolutionarily distant mammalian species. To test the hypothesis that the identified TFs act in combination to regulate the pou4f3 gene, we transfected by electroporation neonatal cochlear sensory epithelium from mice expressing green fluorescent protein (GFP) under the control of an 8.5-kb 5' pou4f3 genomic fragment. Plasmids encoding 21 TFs c-transfected with human ATOH1 (hATOH1). Cotransfection with hETV4, hNMYC, or hETS2 produced significantly more pou4f3/GFP and myosin 7A-positive nonsensory cells than hATOH1 alone. Co-transfection of hATOH1 with hHES1, hHES5, or hNEUROD1 reduced the effects of hATOH1. Chromatin immunoprecipitation (ChIP)of DNA from an inner ear cell line transfected with hNMYC,hETV4, or hETS2 revealed binding to a conserved region immediately proximal to the coding sequence. ChIP similarly revealed binding of hGATA3, hNMYC, and hTFE2 to a region several kilobases distal to the coding sequence, which we have previously shown to bind ATOH1. The results suggest that ATOH1 acts in concert with a subset of other TFs to directly regulate the pou4f3 gene and more broadly to regulate the HC phenotype.
Collapse
|
6
|
Li Y, Liu H, Barta CL, Judge PD, Zhao L, Zhang WJ, Gong S, Beisel KW, He DZZ. Transcription Factors Expressed in Mouse Cochlear Inner and Outer Hair Cells. PLoS One 2016; 11:e0151291. [PMID: 26974322 PMCID: PMC4790917 DOI: 10.1371/journal.pone.0151291] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 02/25/2016] [Indexed: 11/24/2022] Open
Abstract
Regulation of gene expression is essential to determining the functional complexity and morphological diversity seen among different cells. Transcriptional regulation is a crucial step in gene expression regulation because the genetic information is directly read from DNA by sequence-specific transcription factors (TFs). Although several mouse TF databases created from genome sequences and transcriptomes are available, a cell type-specific TF database from any normal cell populations is still lacking. We identify cell type-specific TF genes expressed in cochlear inner hair cells (IHCs) and outer hair cells (OHCs) using hair cell-specific transcriptomes from adult mice. IHCs and OHCs are the two types of sensory receptor cells in the mammalian cochlea. We show that 1,563 and 1,616 TF genes are respectively expressed in IHCs and OHCs among 2,230 putative mouse TF genes. While 1,536 are commonly expressed in both populations, 73 genes are differentially expressed (with at least a twofold difference) in IHCs and 13 are differentially expressed in OHCs. Our datasets represent the first cell type-specific TF databases for two populations of sensory receptor cells and are key informational resources for understanding the molecular mechanism underlying the biological properties and phenotypical differences of these cells.
Collapse
Affiliation(s)
- Yi Li
- Department of Otorhinolaryngology—Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, 68178, United States of America
| | - Huizhan Liu
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, 68178, United States of America
| | - Cody L. Barta
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, 68178, United States of America
| | - Paul D. Judge
- Department of Otorhinolaryngology—Head and Neck Surgery, University of Nebraska Medical Center, Omaha, NE, 68198, United States of America
| | - Lidong Zhao
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, 68178, United States of America
- Department of Otorhinolaryngology—Head and Neck Surgery, Chinese PLA General Hospital, Beijing, 100853, China
| | - Weiping J. Zhang
- Department of Pathophysiology, Second Military Medical University, Shanghai, 200433, China
| | - Shusheng Gong
- Department of Otorhinolaryngology—Head and Neck Surgery, Beijing Friendship Hospital, Beijing, China
| | - Kirk W. Beisel
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, 68178, United States of America
| | - David Z. Z. He
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, 68178, United States of America
- * E-mail:
| |
Collapse
|
7
|
Tropitzsch A, Arnold H, Bassiouni M, Müller A, Eckhard A, Müller M, Löwenheim H. Assessing cisplatin-induced ototoxicity and otoprotection in whole organ culture of the mouse inner ear in simulated microgravity. Toxicol Lett 2014; 227:203-12. [PMID: 24709139 DOI: 10.1016/j.toxlet.2014.03.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 03/25/2014] [Accepted: 03/27/2014] [Indexed: 12/20/2022]
Abstract
Cisplatin is a widely used anti-cancer drug. Ototoxicity is a major dose-limiting side-effect. A reproducible mammalian in-vitro model of cisplatin ototoxicity is required to screen and validate otoprotective drug candidates. We utilized a whole organ culture system of the postnatal mouse inner ear in a rotating wall vessel bioreactor under "simulated microgravity" culture conditions. As previously described this system allows whole organ culture of the inner ear and quantitative assessment of ototoxic effects of aminoglycoside induced hair cell loss. Here we demonstrate that this model is also applicable to the assessment of cisplatin induced ototoxicity. In this model cisplatin induced hair cell loss was dose and time dependent. Increasing exposure time of cisplatin led to decreasing EC50 concentrations. Outer hair cells were more susceptible than inner hair cells, and hair cells in the cochlear base were more susceptible than hair cells in the cochlear apex. Initial cisplatin dose determined the final extent of hair cell loss irrespective if the drug was withdrawn or continued. Dose dependant otoprotection was demonstrated by co-administration of the antioxidant agent N-acetyl l-cysteine. The results support the use of this inner ear organ culture system as an in vitro assay and validation platform for inner ear toxicology and the search for otoprotective compounds.
Collapse
Affiliation(s)
- Anke Tropitzsch
- University of Tübingen Medical School, Department of Otorhinolaryngology - Head & Neck Surgery, Hearing Research Center, Elfriede-Aulhorn-Straße 5, D-72076 Tübingen, Germany.
| | - Heinz Arnold
- University of Tübingen Medical School, Department of Otorhinolaryngology - Head & Neck Surgery, Hearing Research Center, Elfriede-Aulhorn-Straße 5, D-72076 Tübingen, Germany.
| | - Mohamed Bassiouni
- University of Tübingen Medical School, Department of Otorhinolaryngology - Head & Neck Surgery, Hearing Research Center, Elfriede-Aulhorn-Straße 5, D-72076 Tübingen, Germany.
| | - Andrea Müller
- University of Tübingen Medical School, Department of Otorhinolaryngology - Head & Neck Surgery, Hearing Research Center, Elfriede-Aulhorn-Straße 5, D-72076 Tübingen, Germany.
| | - Andreas Eckhard
- University of Tübingen Medical School, Department of Otorhinolaryngology - Head & Neck Surgery, Hearing Research Center, Elfriede-Aulhorn-Straße 5, D-72076 Tübingen, Germany.
| | - Marcus Müller
- University of Tübingen Medical School, Department of Otorhinolaryngology - Head & Neck Surgery, Hearing Research Center, Elfriede-Aulhorn-Straße 5, D-72076 Tübingen, Germany.
| | - Hubert Löwenheim
- University of Tübingen Medical School, Department of Otorhinolaryngology - Head & Neck Surgery, Hearing Research Center, Elfriede-Aulhorn-Straße 5, D-72076 Tübingen, Germany.
| |
Collapse
|
8
|
Abstract
The study of MYC has led to pivotal discoveries in cancer biology, induced pluripotency, and transcriptional regulation. In this review, continuing advances in our understanding of the function of MYC as a transcription factor and how its transcriptional activity controls normal vertebrate development and contributes to developmental disorders is discussed.
Collapse
Affiliation(s)
- Peter J Hurlin
- Shriners Hospitals for Children Portland, Portland, Oregon 97239
| |
Collapse
|
9
|
Kopecky BJ, Jahan I, Fritzsch B. Correct timing of proliferation and differentiation is necessary for normal inner ear development and auditory hair cell viability. Dev Dyn 2013. [PMID: 23193000 DOI: 10.1002/dvdy.23910] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Hearing restoration through hair cell regeneration will require revealing the dynamic interactions between proliferation and differentiation during development to avoid the limited viability of regenerated hair cells. Pax2-Cre N-Myc conditional knockout (CKO) mice highlighted the need of N-Myc for proper neurosensory development and possible redundancy with L-Myc. The late-onset hair cell death in the absence of early N-Myc expression could be due to mis-regulation of genes necessary for neurosensory formation and maintenance, such as Neurod1, Atoh1, Pou4f3, and Barhl1. RESULTS Pax2-Cre N-Myc L-Myc double CKO mice show that proliferation and differentiation are linked together through Myc and in the absence of both Mycs, altered proliferation and differentiation result in morphologically abnormal ears. In particular, the organ of Corti apex is re-patterned into a vestibular-like organization and the base is truncated and fused with the saccule. CONCLUSIONS These data indicate that therapeutic approaches to restore hair cells must take into account a dynamic interaction of proliferation and differentiation regulation of basic Helix-Loop-Helix transcription factors in attempts to stably replace lost cochlear hair cells. In addition, our data indicate that Myc is an integral component of the evolutionary transformation process that resulted in the organ of Corti development.
Collapse
|
10
|
Coupling the cell cycle to development and regeneration of the inner ear. Semin Cell Dev Biol 2013; 24:507-13. [PMID: 23665151 DOI: 10.1016/j.semcdb.2013.04.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 04/23/2013] [Indexed: 12/19/2022]
Abstract
Cell cycle exit and acquirement of a postmitotic state is essential for the proper development of organs. In the present review, we examine the role of the cell cycle control in the sensory epithelia of the mammalian inner ear. We describe the roles of the core cell cycle regulators in the proliferation of prosensory cells and in the initiation and maintenance of terminal mitosis of the sensory epithelia. We also discuss how other intracellular signalling may influence the cell cycle. Finally, we address the question of whether manipulations of the cell cycle may have the potential to create replacement cells for the damaged inner sensory epithelia.
Collapse
|
11
|
Kopecky BJ, Duncan JS, Elliott KL, Fritzsch B. Three-dimensional reconstructions from optical sections of thick mouse inner ears using confocal microscopy. J Microsc 2012; 248:292-8. [PMID: 23140378 PMCID: PMC3625616 DOI: 10.1111/j.1365-2818.2012.03673.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Three-dimensional (3D) reconstructions of the vertebrate inner ear have provided novel insights into the development of this complex organ. 3D reconstructions enable superior analysis of phenotypic differences between wild type and mutant ears but can result in laborious work when reconstructed from physically sectioned material. Although nondestructive optical sectioning light sheet microscopy may ultimately prove the ideal solution, these technologies are not yet commercially available, or in many instances are not monetarily feasible. Here we introduce a simple technique to image a fluorescently labelled ear at different stages throughout development at high resolution enabling 3D reconstruction of any component of the inner ear using confocal microscopy. We provide a step-by-step manual from tissue preparation to imaging to 3D reconstruction and analysis including a rationale and troubleshooting guide at each step for researchers with different equipment, protocols, and access to resources to successfully incorporate the principles of this method and customize them to their laboratory settings.
Collapse
Affiliation(s)
- B J Kopecky
- Department of Biology, University of Iowa, Iowa City, Iowa, USA.
| | | | | | | |
Collapse
|
12
|
Kopecky B, Fritzsch B. The myc road to hearing restoration. Cells 2012; 1:667-98. [PMID: 24710525 PMCID: PMC3901154 DOI: 10.3390/cells1040667] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/12/2012] [Accepted: 09/14/2012] [Indexed: 01/01/2023] Open
Abstract
Current treatments for hearing loss, the most common neurosensory disorder, do not restore perfect hearing. Regeneration of lost organ of Corti hair cells through forced cell cycle re-entry of supporting cells or through manipulation of stem cells, both avenues towards a permanent cure, require a more complete understanding of normal inner ear development, specifically the balance of proliferation and differentiation required to form and to maintain hair cells. Direct successful alterations to the cell cycle result in cell death whereas regulation of upstream genes is insufficient to permanently alter cell cycle dynamics. The Myc gene family is uniquely situated to synergize upstream pathways into downstream cell cycle control. There are three Mycs that are embedded within the Myc/Max/Mad network to regulate proliferation. The function of the two ear expressed Mycs, N-Myc and L-Myc were unknown less than two years ago and their therapeutic potentials remain speculative. In this review, we discuss the roles the Mycs play in the body and what led us to choose them to be our candidate gene for inner ear therapies. We will summarize the recently published work describing the early and late effects of N-Myc and L-Myc on hair cell formation and maintenance. Lastly, we detail the translational significance of our findings and what future work must be performed to make the ultimate hearing aid: the regeneration of the organ of Corti.
Collapse
Affiliation(s)
- Benjamin Kopecky
- Department of Biology, 143 Biology Building, University of Iowa, Iowa City, IA 52242, USA.
| | - Bernd Fritzsch
- Department of Biology, 143 Biology Building, University of Iowa, Iowa City, IA 52242, USA.
| |
Collapse
|