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Liao Y, Mao H, Gao X, Lin H, Li W, Chen Y, Li H. Drug screening identifies aldose reductase as a novel target for treating cisplatin-induced hearing loss. Free Radic Biol Med 2024; 210:430-447. [PMID: 38056576 DOI: 10.1016/j.freeradbiomed.2023.11.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 11/08/2023] [Accepted: 11/24/2023] [Indexed: 12/08/2023]
Abstract
Cisplatin is a frequently used chemotherapeutic medicine for cancer treatment. Permanent hearing loss is one of the most serious side effects of cisplatin, but there are few FDA-approved medicines to prevent it. We applied high-through screening and target fishing and identified aldose reductase, a key enzyme of the polyol pathway, as a novel target for treating cisplatin ototoxicity. Cisplatin treatment significantly increased the expression level and enzyme activity of aldose reductase in the cochlear sensory epithelium. Genetic knockdown or pharmacological inhibition of aldose reductase showed a significant protective effect on cochlear hair cells. Cisplatin-induced overactivation of aldose reductase led to the decrease of NADPH/NADP+ and GSH/GSSG ratios, as well as the increase of oxidative stress, and contributed to hair cell death. Results of target prediction, molecular docking, and enzyme activity detection further identified that Tiliroside was an effective inhibitor of aldose reductase. Tiliroside was proven to inhibit the enzymatic activity of aldose reductase via competitively interfering with the substrate-binding region. Both Tiliroside and another clinically approved aldose reductase inhibitor, Epalrestat, inhibited cisplatin-induced oxidative stress and subsequent cell death and thus protected hearing function. These findings discovered the role of aldose reductase in the pathogenesis of cisplatin-induced deafness and identified aldose reductase as a new target for the prevention and treatment of hearing loss.
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Affiliation(s)
- Yaqi Liao
- Department of Otorhinolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230031, PR China; NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031, PR China; ENT Institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, PR China
| | - Huanyu Mao
- Department of Otorhinolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230031, PR China; NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031, PR China; ENT Institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, PR China
| | - Xian Gao
- Department of Otorhinolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230031, PR China; NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031, PR China; ENT Institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, PR China
| | - Hailiang Lin
- Department of Otorhinolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230031, PR China; NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031, PR China; ENT Institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, PR China
| | - Wenyan Li
- Department of Otorhinolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230031, PR China; Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, PR China; NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031, PR China; The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, PR China; ENT Institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, PR China.
| | - Yan Chen
- Department of Otorhinolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230031, PR China; NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031, PR China; ENT Institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, PR China.
| | - Huawei Li
- Department of Otorhinolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230031, PR China; Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, PR China; NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031, PR China; The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, PR China; ENT Institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, PR China.
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Tao Y, Lamas V, Du W, Zhu W, Li Y, Whittaker MN, Zuris JA, Thompson DB, Rameshbabu AP, Shu Y, Gao X, Hu JH, Pei C, Kong WJ, Liu X, Wu H, Kleinstiver BP, Liu DR, Chen ZY. Treatment of monogenic and digenic dominant genetic hearing loss by CRISPR-Cas9 ribonucleoprotein delivery in vivo. Nat Commun 2023; 14:4928. [PMID: 37582836 PMCID: PMC10427623 DOI: 10.1038/s41467-023-40476-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 07/31/2023] [Indexed: 08/17/2023] Open
Abstract
Mutations in Atp2b2, an outer hair cell gene, cause dominant hearing loss in humans. Using a mouse model Atp2b2Obl/+, with a dominant hearing loss mutation (Oblivion), we show that liposome-mediated in vivo delivery of CRISPR-Cas9 ribonucleoprotein complexes leads to specific editing of the Obl allele. Large deletions encompassing the Obl locus and indels were identified as the result of editing. In vivo genome editing promotes outer hair cell survival and restores their function, leading to hearing recovery. We further show that in a double-dominant mutant mouse model, in which the Tmc1 Beethoven mutation and the Atp2b2 Oblivion mutation cause digenic genetic hearing loss, Cas9/sgRNA delivery targeting both mutations leads to partial hearing recovery. These findings suggest that liposome-RNP delivery can be used as a strategy to recover hearing with dominant mutations in OHC genes and with digenic mutations in the auditory hair cells, potentially expanding therapeutics of gene editing to treat hearing loss.
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Affiliation(s)
- Yong Tao
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Veronica Lamas
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
- Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Wan Du
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
| | - Wenliang Zhu
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
| | - Yiran Li
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
- C.S. Mott Children's Hospital, Ann Harbor, MI, USA
| | - Madelynn N Whittaker
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, 02114, USA
- Department of Pathology, Massachusetts General hospital, Boston, MA, 02114, USA
| | - John A Zuris
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - David B Thompson
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Arun Prabhu Rameshbabu
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
| | - Yilai Shu
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, NHC Key Laboratory of Hearing Medicine, Institutes of Biomedical Sciences, Fudan University, Shanghai, 200031, China
| | - Xue Gao
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Johnny H Hu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Charles Pei
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
| | - Wei-Jia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xuezhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Hao Wu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Benjamin P Kleinstiver
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, 02114, USA
- Department of Pathology, Massachusetts General hospital, Boston, MA, 02114, USA
- Department of Pathology, Harvard Medical School, Boston, MA, 02115, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA.
| | - Zheng-Yi Chen
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA.
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA.
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Wijesinghe P, Sastry A, Hui E, Cogan TA, Zheng B, Ho G, Kakal J, Nunez DA. Adult porcine (Sus scrofa) derived inner ear cells: Characteristics in in-vitro cultures. Anat Rec (Hoboken) 2023. [PMID: 36598271 DOI: 10.1002/ar.25149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/21/2022] [Accepted: 12/10/2022] [Indexed: 01/05/2023]
Abstract
There is a need for an animal model that closely parallels human cochlea gestational development. This study aims to document porcine inner ear anatomy, and in vitro porcine derived inner ear cell culture characteristics. Twenty-four temporal bone were harvested from 12 adult pigs (Sus scrofa). Six were formalin fixed and their maximal diameters were measured. The cochlea duct length was determined by the insertion length of a Nucleus 22 cochlear implant in two bones. Four formalin fixed bones were sectioned for histology. Cochlear and vestibular tissues were harvested from non-fixed bones, cultured and characterized at different passages (P). Gene and protein expression of multipotent stem/progenitor (Nestin and Sox2), inner ear hair (Myosin VIIa, Prestin) and supporting (Cytokeratin 18 and Vimentin) cell markers were determined. The porcine cochlea was a 3.5 turn spiral. There was a separate vestibular compartment. The cochlear mean maximal diameter and height was 7.99 and 3.77 mm, respectively. Sphere forming cells were identified on phase-contrast microscopy. The relative mRNA expression levels of KRT18, MYO7A and SLC26A5 were significantly positively correlated in cochlear cultures; and MYO7A and SLC26A5; SOX2 and KRT18; NES and SLC26A5 genes were positively correlated in vestibular cultures (p = .037, Spearman correlation [τ] = .900). Inner ear sensory and stem cell characteristics persist in passaged porcine inner ear cells. Further work is required to establish the usefulness of porcine inner ear cell cultures to the study of human inner ear disorders.
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Affiliation(s)
- Printha Wijesinghe
- Division of Otolaryngology, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada
| | - Anand Sastry
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Elizabeth Hui
- Division of Otolaryngology, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada
| | - Tristan A Cogan
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Boyuan Zheng
- Division of Otolaryngology, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada
| | - Germain Ho
- Division of Otolaryngology, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada
| | - Juzer Kakal
- Division of Otolaryngology, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada
| | - Desmond A Nunez
- Division of Otolaryngology, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada
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4
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Liquid Crystalline Nanoparticles Conjugated with Dexamethasone Prevent Cisplatin Ototoxicity In Vitro. Int J Mol Sci 2022; 23:ijms232314881. [PMID: 36499206 PMCID: PMC9741167 DOI: 10.3390/ijms232314881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 11/29/2022] Open
Abstract
The conjugation of drugs with nanoparticles represents an innovative approach for controlled and targeted administration of therapeutic agents. Nanoparticle-based systems have been tested for the inner ear therapy, increasing the drug diffusion and being detected in all parts of the cochlea when locally applied near the round window. In this study, glycerol monooleate liquid crystalline NanoParticles were conjugated with Dexamethasone (NPD), a hydrophobic drug already used for inner ear treatments but defective in solubility and bioavailability. NPD has been tested in vitro in the cell line OC-k3, a model of sensory cells of the inner ear, and the therapeutic efficacy has been evaluated against cisplatin, a chemotherapeutic compound known to induce ototoxicity. After comparing the physical chemical characteristics of NPD to the equivalent naïve nanoparticles, an initial investigation was carried out into the nanoparticle's uptake in OC-k3 cells, which takes place within a few hours of treatment without causing toxic damage up to a concentration of 50 µg/mL. The NPD delivered the dexamethasone inside the cells at a significantly increased rate compared to the equivalent free drug administration, increasing the half-life of the therapeutic compound within the cell. Concerning the co-treatment with cisplatin, the NPD significantly lowered the cisplatin cytotoxicity after 48 h of administration, preventing cell apoptosis. To confirm this result, also cell morphology, cell cycle and glucocorticoids receptor expression were investigated. In conclusion, the NPD system has thus preliminarily shown the potential to improve the therapeutic efficacy of treatments delivered in the inner ear and prevent drug-induced ototoxicity.
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5
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Role of Oxidative Stress in the Senescence Pattern of Auditory Cells in Age-Related Hearing Loss. Antioxidants (Basel) 2021; 10:antiox10091497. [PMID: 34573129 PMCID: PMC8464759 DOI: 10.3390/antiox10091497] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/09/2021] [Accepted: 09/18/2021] [Indexed: 01/10/2023] Open
Abstract
Age-related hearing loss (ARHL) is an increasing and gradual sensorineural hearing dysfunction. Oxidative stress is an essential factor in developing ARHL; additionally, premature senescence of auditory cells induced by oxidative stress can produce hearing loss. Hydrogen peroxide (H2O2) represents a method commonly used to generate cellular senescence in vitro. The objective of the present paper is to study H2O2-induced senescence patterns in three auditory cell lines (House Ear Institute-Organ of Corti 1, HEI-OC1; organ of Corti, OC-k3, and stria vascularis, SV-k1 cells) to elucidate the intrinsic mechanisms responsible for ARHL. The auditory cells were exposed to H2O2 at different concentrations and times. The results obtained show different responses of the hearing cells concerning cell growth, β-galactosidase activity, morphological changes, mitochondrial activation, levels of oxidative stress, and other markers of cell damage (Forkhead box O3a, FoxO3a, and 8-oxoguanine, 8-oxoG). Comparison between the responses of these auditory cells to H2O2 is a helpful method to evaluate the molecular mechanisms responsible for these auditory cells' senescence. Furthermore, this in vitro model could help develop anti-senescent therapeutic strategies for the treatment of AHRL.
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6
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Fetoni AR, Astolfi L. Cisplatin ototoxicity and role of antioxidant on its prevention. HEARING, BALANCE AND COMMUNICATION 2020. [DOI: 10.1080/21695717.2020.1810962] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Anna Rita Fetoni
- Department of Head and Neck Surgery, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Roma, Italia
| | - Laura Astolfi
- Bioacoustics Research Laboratory, Department of Neuroscience, University of Padua, Padua, Italy
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7
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Sphingosine 1-Phosphate Receptor 2 Induces Otoprotective Responses to Cisplatin Treatment. Cancers (Basel) 2020; 12:cancers12010211. [PMID: 31952197 PMCID: PMC7016659 DOI: 10.3390/cancers12010211] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 11/08/2019] [Accepted: 01/09/2020] [Indexed: 12/19/2022] Open
Abstract
Ototoxicity is a major adverse effect of platinum-based chemotherapeutics and currently, there remains a lack of United States Food and Drug Administration-approved therapies to prevent or treat this problem. In our study, we examined the role of the sphingosine 1-phosphate receptor 2 (S1P2) in attenuating cisplatin-induced ototoxicity in several different animal models and cell lines. We found that ototoxicity in S1P2 knockout mice is dependent on reactive oxygen species (ROS) production and that S1P2 receptor activation with a specific agonist, CYM-5478, significantly attenuates cisplatin-induced defects, including hair cell degeneration in zebrafish and prolonged auditory brainstem response latency in rats. We also evaluated the cytoprotective effect of CYM-5478 across different cell lines and showed that CYM-5478 protects neural-derived cell lines but not breast cancer cells against cisplatin toxicity. We show that this selective protection of CYM-5478 is due to its differential effects on key regulators of apoptosis between neural cells and breast cancer cells. Overall, our study suggests that targeting the S1P2 receptor represents a promising therapeutic approach for the treatment of cisplatin-induced ototoxicity in cancer patients.
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Kojima K, Nishida AT, Tashiro K, Hirota K, Nishio T, Murata M, Kato N, Kawaguchi S, Zine A, Ito J, Van De Water TR. Isolation and Characterization of Mammalian Otic Progenitor Cells that Can Differentiate into Both Sensory Epithelial and Neuronal Cell Lineages. Anat Rec (Hoboken) 2020; 303:451-460. [PMID: 31943808 DOI: 10.1002/ar.24335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 11/25/2019] [Accepted: 12/03/2019] [Indexed: 01/01/2023]
Abstract
The mammalian inner ear mediates hearing and balance and during development generates both cochleo-vestibular ganglion neurons and sensory epithelial receptor cells, that is, hair cells and support cells. Cell marking experiments have shown that both hair cells and support cells can originate from a common progenitor. Here, we demonstrate the lineage potential of individual otic epithelial cell clones using three cell lines established by a combination of limiting dilution and gene-marking techniques from an embryonic day 12 (E12) rat otocyst. Cell-type specific marker analyses of these clonal lines under proliferation and differentiation culture conditions demonstrate that during differentiation immature cell markers (Nanog and Nestin) were downregulated and hair cell (Myosin VIIa and Math1), support cell (p27Kip1 and cytokeratin) and neuronal cell (NF-H and NeuroD) markers were upregulated. Our results suggest that the otic epithelium of the E12 mammalian inner ear possess multipotent progenitor cells able to generate cell types of both sensory epithelial and neural cell lineages when cultured under a differentiation culture condition. Understanding the molecular mechanisms of proliferation and differentiation of multipotent otic progenitor cells may provide insights that could contribute to the development of a novel cell therapy with a potential to initiate or stimulate the sensorineural repair of damaged inner ear sensory receptors. Anat Rec, 303:451-460, 2020. © 2019 American Association for Anatomy.
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Affiliation(s)
- Ken Kojima
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.,University of Miami Ear Institute, Department of Otolaryngology, University of Miami School of Medicine, Miami, Florida.,Department of Integrative Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Akiko T Nishida
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.,Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan.,Center for Molecular Biology and Genetics, Kyoto University, Kyoto, Japan
| | - Kei Tashiro
- Center for Molecular Biology and Genetics, Kyoto University, Kyoto, Japan
| | - Kiichi Hirota
- BioMedical Special Research Unit, Human Stress Signal Research Center, National Institute of Advanced Industrial Science and Technology, Ikeda, Japan
| | - Takeshi Nishio
- Department of Integrative Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Miyahiko Murata
- Department of Integrative Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Nobuo Kato
- Department of Integrative Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Saburo Kawaguchi
- Department of Integrative Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Azel Zine
- Institute of Neuroscience, INSERM U. 583, University of Montpellier I, Montpellier, France
| | - Juichi Ito
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Thomas R Van De Water
- University of Miami Ear Institute, Department of Otolaryngology, University of Miami School of Medicine, Miami, Florida
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Simoni E, Valente F, Boge L, Eriksson M, Gentilin E, Candito M, Cazzador D, Astolfi L. Biocompatibility of glycerol monooleate nanoparticles as tested on inner ear cells. Int J Pharm 2019; 572:118788. [DOI: 10.1016/j.ijpharm.2019.118788] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 10/10/2019] [Accepted: 10/11/2019] [Indexed: 12/13/2022]
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10
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Lower ototoxicity and absence of hidden hearing loss point to gentamicin C1a and apramycin as promising antibiotics for clinical use. Sci Rep 2019; 9:2410. [PMID: 30787404 PMCID: PMC6382871 DOI: 10.1038/s41598-019-38634-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 11/29/2018] [Indexed: 11/08/2022] Open
Abstract
Spread of antimicrobial resistance and shortage of novel antibiotics have led to an urgent need for new antibacterials. Although aminoglycoside antibiotics (AGs) are very potent anti-infectives, their use is largely restricted due to serious side-effects, mainly nephrotoxicity and ototoxicity. We evaluated the ototoxicity of various AGs selected from a larger set of AGs on the basis of their strong antibacterial activities against multidrug-resistant clinical isolates of the ESKAPE panel: gentamicin, gentamicin C1a, apramycin, paromomycin and neomycin. Following local round window application, dose-dependent effects of AGs on outer hair cell survival and compound action potentials showed gentamicin C1a and apramycin as the least toxic. Strikingly, although no changes were observed in compound action potential thresholds and outer hair cell survival following treatment with low concentrations of neomycin, gentamicin and paromomycin, the number of inner hair cell synaptic ribbons and the compound action potential amplitudes were reduced. This indication of hidden hearing loss was not observed with gentamicin C1a or apramycin at such concentrations. These findings identify the inner hair cells as the most vulnerable element to AG treatment, indicating that gentamicin C1a and apramycin are promising bases for the development of clinically useful antibiotics.
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11
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Lim HW, Pak K, Ryan AF, Kurabi A. Screening Mammalian Cochlear Hair Cells to Identify Critical Processes in Aminoglycoside-Mediated Damage. Front Cell Neurosci 2018; 12:179. [PMID: 30013464 PMCID: PMC6036173 DOI: 10.3389/fncel.2018.00179] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/07/2018] [Indexed: 12/22/2022] Open
Abstract
There is considerable interest in discovering drugs with the potential to protect inner ear hair cells (HCs) from damage. One means of discovery is to screen compound libraries. Excellent screening protocols have been developed employing cell lines derived from the cochlea and zebrafish larvae. However, these do not address the differentiated mammalian hair cell. We have developed a screening method employing micro-explants of the mammalian organ of Corti (oC) to identify compounds with the ability to influence aminoglycoside-induced HC loss. The assay is based on short segments of the neonatal mouse oC, containing ~80 HCs which selectively express green fluorescent protein (GFP). This allows the screening of hundreds of potential protectants in an assay that includes both inner and outer HCs. This review article describes various screening methods, including the micro-explant assay. In addition, two micro-explant screening studies in which antioxidant and kinase inhibitor libraries were evaluated are reviewed. The results from these screens are related to current models of HC damage and protection.
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Affiliation(s)
- Hyun Woo Lim
- Division of Otolaryngology, Department of Surgery, University of California, San Diego, La Jolla, CA, United States.,Department of Otolaryngology, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, South Korea
| | - Kwang Pak
- Division of Otolaryngology, Department of Surgery, University of California, San Diego, La Jolla, CA, United States.,San Diego VA Healthcare System, La Jolla, CA, United States
| | - Allen F Ryan
- Division of Otolaryngology, Department of Surgery, University of California, San Diego, La Jolla, CA, United States.,San Diego VA Healthcare System, La Jolla, CA, United States.,Department of Neurosciences, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Arwa Kurabi
- Division of Otolaryngology, Department of Surgery, University of California, San Diego, La Jolla, CA, United States
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12
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Bhavsar AP, Gunaretnam EP, Li Y, Hasbullah JS, Carleton BC, Ross CJD. Pharmacogenetic variants in TPMT alter cellular responses to cisplatin in inner ear cell lines. PLoS One 2017; 12:e0175711. [PMID: 28406961 PMCID: PMC5391095 DOI: 10.1371/journal.pone.0175711] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 03/30/2017] [Indexed: 11/19/2022] Open
Abstract
Cisplatin is a highly-effective and widely-used chemotherapeutic agent that causes ototoxicity in many patients. Pharmacogenomic studies of key genes controlling drug biotransformation identified variants in thiopurine methyltransferase (TPMT) as predictors of cisplatin-induced ototoxicity, although the mechanistic basis of this interaction has not been reported. Expression constructs of TPMT*3A, *3B and *3C variants were generated and monitored in cultured cells. Cellular TPMT*3A levels were detected at >20-fold lower amounts than the wild type confirming the unstable nature of this variant. The expression of wild type TPMT (TPMT*1) in two murine ear cell lines, HEI-OC1 and UB/OC-1, significantly mitigated their susceptibility to cisplatin toxicity. Cisplatin treatment induced Tlr4 gene expression in HEI-OC1 cells and this response was blunted by the expression of wild type TPMT but not TPMT*3A. In line with the significant mitigation of TPMT*1-expressing cells to cisplatin cytotoxicity, these findings demonstrate a drug-gene interaction between increased TPMT activity and decreased susceptibility to cisplatin-induced toxicity of inner ear cells.
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Affiliation(s)
- Amit P. Bhavsar
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Erandika P. Gunaretnam
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Division of Translational Therapeutics, Department of Pediatrics, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Yuling Li
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Division of Translational Therapeutics, Department of Pediatrics, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Jafar S. Hasbullah
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Medical Genetics, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Bruce C. Carleton
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Division of Translational Therapeutics, Department of Pediatrics, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Colin J. D. Ross
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- * E-mail:
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Abstract
HEI-OC1 is one of the few mouse auditory cell lines available for research purposes. Originally proposed as an in vitro system for screening of ototoxic drugs, these cells have been used to investigate drug-activated apoptotic pathways, autophagy, senescence, mechanism of cell protection, inflammatory responses, cell differentiation, genetic and epigenetic effects of pharmacological drugs, effects of hypoxia, oxidative and endoplasmic reticulum stress, and expression of molecular channels and receptors. Among other several important markers of cochlear hair cells, HEI-OC1 cells endogenously express prestin, the paradigmatic motor protein of outer hair cells. Thus, they can be very useful to elucidate novel functional aspects of this important auditory protein. HEI-OC1 cells are very robust, and their culture usually does not present big complications. However, they require some special conditions such as avoiding the use of common anti-bacterial cocktails containing streptomycin or other antibiotics as well as incubation at 33 °C to stimulate cell proliferation and incubation at 39 °C to trigger cell differentiation. Here, we describe how to culture HEI-OC1 cells and how to use them in some typical assays, such as cell proliferation, viability, death, autophagy and senescence, as well as how to perform patch-clamp and non-linear capacitance measurements.
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Affiliation(s)
- Gilda M Kalinec
- Head and Neck Surgery, David Geffen School of Medicine, University of California, Los Angeles
| | - Channy Park
- Head and Neck Surgery, David Geffen School of Medicine, University of California, Los Angeles
| | - Pru Thein
- Head and Neck Surgery, David Geffen School of Medicine, University of California, Los Angeles
| | - Federico Kalinec
- Head and Neck Surgery, David Geffen School of Medicine, University of California, Los Angeles;
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Kempfle JS, Turban JL, Edge ASB. Sox2 in the differentiation of cochlear progenitor cells. Sci Rep 2016; 6:23293. [PMID: 26988140 PMCID: PMC4796895 DOI: 10.1038/srep23293] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 03/02/2016] [Indexed: 12/19/2022] Open
Abstract
HMG domain transcription factor, Sox2, is a critical gene for the development of cochlear hair cells, the receptor cells for hearing, but this has been ascribed to expansion of the progenitors that become hair cells. Here, we show that Sox2 activated Atoh1, a transcription factor important for hair cell differentiation, through an interaction with the 3′ enhancer of Atoh1. Binding to consensus sequences in the Atoh1 enhancer was dependent on the level of Sox2, and the extent of enhancer binding correlated to the extent of activation. Atoh1 activation by Sox2 was required for embryonic hair cell development: deletion of Sox2 in an inducible mutant, even after progenitor cells were fully established, halted development of hair cells, and silencing also inhibited postnatal differentiation of hair cells induced by inhibition of γ-secretase. Sox2 is thus required in the cochlea to both expand the progenitor cells and initiate their differentiation to hair cells.
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Affiliation(s)
- Judith S Kempfle
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02115, USA.,Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA
| | - Jack L Turban
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02115, USA.,Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA
| | - Albert S B Edge
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02115, USA.,Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA.,Program in Speech and Hearing Bioscience and Technology, Division of Health Science and Technology, Harvard &MIT, Cambridge, MA 02139, USA
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15
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Astolfi L, Simoni E, Martini A. OC-k3 cells, anin vitromodel for cochlear implant biocompatibility. HEARING BALANCE AND COMMUNICATION 2015. [DOI: 10.3109/21695717.2015.1063232] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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16
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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.
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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.
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Altun Z, Olgun Y, Ercetin P, Aktas S, Kirkim G, Serbetcioglu B, Olgun N, Guneri EA. Protective effect of acetyl-l-carnitine against cisplatin ototoxicity: role of apoptosis-related genes and pro-inflammatory cytokines. Cell Prolif 2013; 47:72-80. [PMID: 24286513 DOI: 10.1111/cpr.12080] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 09/15/2013] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVES Cisplatin is an anti-neoplastic agent treatment with which causes many side effects including ototoxicity. The aim of this study was to investigate whether acetyl-L-carnitine would have protective effects on cisplatin-induced ototoxicity in vitro, and if present, to reveal roles of apoptotic gene expressions and pro-inflammatory cytokines. MATERIALS AND METHODS House Ear Institute-Organ of Corti 1 cell line was used for this study. Apoptotic genes were evaluated with an apoptosis PCR array and pro-inflammatory cytokine levels were measured using ELISA. RESULTS Apoptotic cell death reduced by around 22% with acetyl-L-carnitine-cisplatin treatment compared to cisplatin alone. Genes displaying increase in expression of apoptosis, related to cisplatin treatment, were Casp8, Bcl10, Bcl2, Bcl2l1, Bcl2l2, Bid, Naip1, Bnip3l, Card6, Pak7, Cd40, Trp 53inp1, Cideb and Cd70. The acetyl-L-carnitine-cisplatin combination caused reduced expression of genes Casp8, Fas, Casp1, Tnfrsf11b, Tnfrsf10b induced by cisplatin. Acetyl-L-carnitine-cisplatin also caused reduced levels of IL-6, IL-1β and TNF-α, pro-inflammatory cytokines, induced by cisplatin. CONCLUSION Protective mechanisms of aceytl-L-carnitine against cisplatin induced apoptosis, mainly due to activation of anti-apoptotic Bcl family members' genes, and in an Akt-related gene expression dependent manner. This is the first study to indicate that acetyl-L-carnitine can be an effective agent against cisplatin ototoxicity in auditory cells, with induction of anti-apoptotic gene expression and attenuating levels of pro-inflammatory cytokines.
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Affiliation(s)
- Z Altun
- Department of Basic Oncology, Institute of Oncology, Dokuz Eylul University, Izmir, 35340, Turkey
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18
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Ye F, Laurent S, Fornara A, Astolfi L, Qin J, Roch A, Martini A, Toprak MS, Muller RN, Muhammed M. Uniform mesoporous silica coated iron oxide nanoparticles as a highly efficient, nontoxic MRI T(2) contrast agent with tunable proton relaxivities. CONTRAST MEDIA & MOLECULAR IMAGING 2013; 7:460-8. [PMID: 22821880 DOI: 10.1002/cmmi.1473] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Monodisperse mesoporous silica (mSiO(2) ) coated superparamagnetic iron oxide (Fe(3) O(4) @mSiO(2) ) nanoparticles (NPs) have been developed as a potential magnetic resonance imaging (MRI) T(2) contrast agent. To evaluate the effect of surface coating on MRI contrast efficiency, we examined the proton relaxivities of Fe(3) O(4) @mSiO(2) NPs with different coating thicknesses. It was found that the mSiO(2) coating has a significant impact on the efficiency of Fe(3) O(4) NPs for MRI contrast enhancement. The efficiency increases with the thickness of mSiO(2) coating and is much higher than that of the commercial contrast agents. Nuclear magnetic resonance (NMR) relaxometry of Fe(3) O(4) @mSiO(2) further revealed that mSiO(2) coating is partially permeable to water molecules and therefore induces the decrease of longitudinal relaxivity, r(1) . Biocompatibility evaluation of various sized (ca. 35-95 nm) Fe(3) O(4) @mSiO(2) NPs was tested on OC-k3 cells and the result showed that these particles have no negative impact on cell viability. The enhanced MRI efficiency of Fe(3) O(4) @mSiO(2) highlights these core-shell particles as highly efficient T(2) contrast agents with high biocompatibility.
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Affiliation(s)
- Fei Ye
- Functional Materials Division, Royal Institute of Technology (KTH), Electrum 229, 164 40, Kista, Stockholm, Sweden.
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19
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Water channel proteins in the inner ear and their link to hearing impairment and deafness. Mol Aspects Med 2012; 33:612-37. [DOI: 10.1016/j.mam.2012.06.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 06/11/2012] [Accepted: 06/17/2012] [Indexed: 11/24/2022]
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20
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Ou H, Simon JA, Rubel EW, Raible DW. Screening for chemicals that affect hair cell death and survival in the zebrafish lateral line. Hear Res 2012; 288:58-66. [PMID: 22310494 PMCID: PMC3371178 DOI: 10.1016/j.heares.2012.01.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 01/05/2012] [Accepted: 01/23/2012] [Indexed: 02/09/2023]
Abstract
The zebrafish lateral line is an efficient model system for the evaluation of chemicals that protect and damage hair cells. Located on the surface of the body, lateral line hair cells are accessible for manipulation and visualization. The zebrafish lateral line system allows rapid screens of large chemical libraries, as well as subsequent thorough evaluation of interesting compounds. In this review, we focus on the results of our previous screens and the evolving methodology of our screens for chemicals that protect hair cells, and chemicals that damage hair cells using the zebrafish lateral line.
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Affiliation(s)
- Henry Ou
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Box 357923, Seattle, WA 98195-7923, USA.
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21
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Basappa J, Turcan S, Vetter DE. Corticotropin-releasing factor-2 activation prevents gentamicin-induced oxidative stress in cells derived from the inner ear. J Neurosci Res 2010; 88:2976-90. [PMID: 20544827 DOI: 10.1002/jnr.22449] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Generation of reactive oxygen species (ROS) is a common denominator in many conditions leading to cell death in the cochlea, yet little is known of the cochlea's endogenous mechanisms involved in preventing oxidative stress and its consequences in the cochlea. We have recently described a corticotropin-releasing factor (CRF) signaling system in the inner ear involved in susceptibility to noise-induced hearing loss. We use biochemical and proteomics assays to define further the role of CRF signaling in the response of cochlear cells to aminoglycoside exposure. We demonstrate that activity via the CRF(2) class of receptors protects against aminoglycoside-induced ROS production and activation of cell death pathways. This study suggests for the first time a role for CRF signaling in protecting the cochlea against oxidative stress, and our proteomics data suggest novel mechanisms beyond induction of free radical scavengers that are involved in its protective mechanisms.
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Affiliation(s)
- Johnvesly Basappa
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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22
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Ototoxicity from combined Cisplatin and radiation treatment: an in vitro study. Int J Otolaryngol 2010; 2010:523976. [PMID: 21151649 PMCID: PMC2995915 DOI: 10.1155/2010/523976] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 07/29/2010] [Accepted: 08/10/2010] [Indexed: 11/17/2022] Open
Abstract
Objective. Combined cisplatin (CDDP) and radiotherapy is increasingly being used to treat advanced head and neck cancers. As both CDDP and radiation can cause hearing loss, it is important to have a better understanding of the cellular and molecular ototoxic mechanisms involved in combined therapy. Procedure. The effects of CDDP, radiation, and combined CDDP-radiation on the OC-k3 cochlear cell line were studied using MTS assay, flow cytometry, Western blotting, and microarray analysis. Results. Compared to using CDDP or radiation alone, its combined use resulted in enhanced apoptotic cell death and apoptotic-related gene expression, including that of FAS. Phosphorylation of p53 at Ser15 (a marker for p53 pathway activation in response to DNA damage) was observed after treatment with either CDDP or radiation. However, posttreatment activation of p53 occurred earlier in radiation than in CDDP which corresponded to the timings of MDM2 and TP53INP1 expression. Conclusion. Enhanced apoptotic-related gene expressions leading to increased apoptotic cell deaths could explain the synergistic ototoxicity seen clinically in combined CDDP-radiation therapy. CDDP and radiation led to differential temporal activation of p53 which suggests that their activation is the result of different upstream processes. These have implications in future antiapoptotic treatments for ototoxicity.
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23
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Kohn EA, Du Z, Sato M, Van Schyndle CMH, Welsh MA, Yang YA, Stuelten CH, Tang B, Ju W, Bottinger EP, Wakefield LM. A novel approach for the generation of genetically modified mammary epithelial cell cultures yields new insights into TGFβ signaling in the mammary gland. Breast Cancer Res 2010; 12:R83. [PMID: 20942910 PMCID: PMC3096976 DOI: 10.1186/bcr2728] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 07/29/2010] [Accepted: 10/13/2010] [Indexed: 12/14/2022] Open
Abstract
INTRODUCTION Molecular dissection of the signaling pathways that underlie complex biological responses in the mammary epithelium is limited by the difficulty of propagating large numbers of mouse mammary epithelial cells, and by the inability of ribonucleic acid interference (RNAi)-based knockdown approaches to fully ablate gene function. Here we describe a method for the generation of conditionally immortalized mammary epithelial cells with defined genetic defects, and we show how such cells can be used to investigate complex signal transduction processes using the transforming growth factor beta (TGFβ/Smad pathway as an example. METHODS We intercrossed the previously described H-2Kb-tsA58 transgenic mouse (Immortomouse) which expresses a temperature-sensitive mutant of the simian virus-40 large T-antigen (tsTAg), with mice of differing Smad genotypes. A panel of conditionally immortalized mammary epithelial cell (IMEC) cultures were derived from the virgin mammary glands of offspring of these crosses and used to assess the Smad dependency of different biological responses to TGFβ. RESULTS IMECs could be propagated indefinitely at permissive temperatures and had a stable epithelial phenotype, resembling primary mammary epithelial cells with respect to several criteria, including responsiveness to TGFβ. Using this panel of cells, we demonstrated that Smad3, but not Smad2, is necessary for TGFβ-induced apoptotic, growth inhibitory and EMT responses, whereas either Smad can support TGFβ-induced invasion as long as a threshold level of total Smad is exceeded. CONCLUSIONS This work demonstrates the practicality and utility of generating conditionally immortalized mammary epithelial cell lines from genetically modified Immortomice for detailed investigation of complex signaling pathways in the mammary epithelium.
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Affiliation(s)
- Ethan A Kohn
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive MSC 4255, Bethesda MD 20892, USA
| | - Zhijun Du
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive MSC 4255, Bethesda MD 20892, USA
| | - Misako Sato
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive MSC 4255, Bethesda MD 20892, USA
| | - Catherine MH Van Schyndle
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive MSC 4255, Bethesda MD 20892, USA
| | - Michael A Welsh
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive MSC 4255, Bethesda MD 20892, USA
| | - Yu-an Yang
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive MSC 4255, Bethesda MD 20892, USA
| | - Christina H Stuelten
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive MSC 4255, Bethesda MD 20892, USA
| | - Binwu Tang
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive MSC 4255, Bethesda MD 20892, USA
| | - Wenjun Ju
- Department of Internal Medicine, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA
| | - Erwin P Bottinger
- Division of Nephrology, Department of Medicine, Charles R Bronfman Institute for Personalized Medicine, Mount Sinai School of Medicine, 1468 Madison Avenue, New York, NY 10029, USA
| | - Lalage M Wakefield
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive MSC 4255, Bethesda MD 20892, USA
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Ou HC, Santos F, Raible DW, Simon JA, Rubel EW. Drug screening for hearing loss: using the zebrafish lateral line to screen for drugs that prevent and cause hearing loss. Drug Discov Today 2010; 15:265-71. [PMID: 20096805 DOI: 10.1016/j.drudis.2010.01.001] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2009] [Revised: 12/01/2009] [Accepted: 01/06/2010] [Indexed: 12/17/2022]
Abstract
Several animal models have been used for the study of mechanosensory hair cells and hearing loss. Because of the difficulty of tissue acquisition and large animal size, these traditional models are impractical for high-throughput screening. The zebrafish has emerged as a powerful animal model for screening drugs that cause and prevent hair cell death. The unique characteristics of the zebrafish enable rapid in vivo imaging of hair cells and hair cell death. We have used this model to screen for and identify multiple drugs that protect hair cells from aminoglycoside-induced death. The identification of multiple drugs and drug-like compounds that inhibit multiple hair cell death pathways might enable the development of protective cocktails to achieve complete hair cell protection.
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Affiliation(s)
- Henry C Ou
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Box 357923, Seattle, WA 98195, USA.
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25
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Astolfi L, Simoni E, Ciorba A, Martini A. In vitro protective effects of Ginkgo biloba against cisplatin toxicity in mouse cell line OCk3. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/16513860802527930] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Lin J, Feng L, Hamajima Y, Komori M, Burns TC, Fukudome S, Anderson J, Wang D, Verfaillie CM, Low WC. Directed differentiation of mouse cochlear neural progenitors in vitro. Am J Physiol Cell Physiol 2008; 296:C441-52. [PMID: 19261910 DOI: 10.1152/ajpcell.00324.2008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Multipotent cochlear neural progenitors (CNPs) in the organ of Corti hold the promise for cell replacement in degenerative hearing disorders. However, not much is known about the CNPs and the specific conditions for their differentiation. Here we isolate the CNPs from the postnatal day 1 organ of Corti in mice and demonstrate their capability to self-renew and to differentiate into hair cell-like and neuronal cell-like phenotypes under the guidance of sonic hedgehog (SHH), epidermal growth factor (EGF), retinoic acid (RA), and brain-derived neurotrophic factor (BDNF), herein termed SERB (abbreviation of SHH, EGF, RA, and BDNF) in an asymmetric or symmetric manner from clonal isolates. Differentiation of CNPs into hair cells by SERB was dependent on the ERK signaling pathway, whereas the differentiation of CNPs into neurons by SERB was not. This work develops a new in vitro methodology for the maintenance and self-regeneration of CNPs for future design of regenerative strategies for hearing disorders.
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Affiliation(s)
- Jizhen Lin
- Department of Otolaryngology, 216 Lions Research Bldg., Univ. of Minnesota, 2001 Sixth St. S.E., Minneapolis, MN 55455, USA.
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29
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Vrijens K, Van Camp G, Van Laer L. Characterization of the murine Dfna5 promoter and regulatory regions. Gene 2008; 432:82-90. [PMID: 19095048 DOI: 10.1016/j.gene.2008.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 10/30/2008] [Accepted: 11/10/2008] [Indexed: 01/17/2023]
Abstract
Mutations in DFNA5 cause a non-syndromic autosomal dominant type of hearing loss. Although not much is known regarding the physiological function of DFNA5, it is not only related to hearing loss. A clear link with cancer exists. For example, methylation of the 5' flanking region of DFNA5 was detected in breast, colorectal and gastric cancer. So far, this 5' flanking region has not been studied in detail. Here, we describe the identification of the cochlear transcription initiation site (TIS), the identification of the core promoter region between -120 and +70 relative to the TIS and the identification of an enhancer (between -121 and -356 bp) and a silencer element (between -356 and -670 bp). Results were similar in HEK293 cells and in the organ of Corti cell line OC-k3. Transfection with a reversely-oriented construct resulted in high transcriptional activity. We subsequently confirmed this antisense activity and identified a novel antisense transcript partly overlapping Dfna5.
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Affiliation(s)
- Karen Vrijens
- Department of Medical Genetics, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, B-2610 Antwerp, Belgium
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Chung WH, Boo SH, Chung MK, Lee HS, Cho YS, Hong SH. Proapoptotic effects of NF-kappaB on cisplatin-induced cell death in auditory cell line. Acta Otolaryngol 2008; 128:1063-70. [PMID: 18607991 DOI: 10.1080/00016480701881811] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
CONCLUSIONS The findings suggest that nuclear factor (NF)-kappaB is activated by cisplatin and plays a proapoptotic role during cell death in the auditory cell line HEI-OC1. OBJECTIVES Cisplatin is a very effective antineoplastic drug but in high doses it shows ototoxicity by inducing apoptosis of hair cells in the cochlea. NF-kappaB is a transcription factor regulating apoptosis in many organs and tissues. This study examined the role of NF-kappaB in the apoptotic pathway induced by cisplatin in the auditory cell line, HEI-OC1. MATERIALS AND METHODS Apoptotic cell death was identified by measuring caspase 3 activity and immunostaining with anti-caspase 3 antibody after cisplatin treatment (50 microM) for 24 h. To investigate the role of NF-kappaB in apoptotic cell death, HEI-OC1 cells treated with 50 microM of cisplatin were immunostained with anti-NF-kappaB (p65) antibody. Two different NF-kappaB inhibitors, Bay 11-7085 and SN-50, were co-incubated with cisplatin (50 microM) for 24 h and caspase 3 activity was assayed. RESULTS Immunostaining with anti-caspase 3 antibody and caspase 3 assay showed that cisplatin induced apoptosis in HEI-OC1 cells. After cisplatin treatment, NF-kappaB (p65) was activated to translocate from the cytoplasm into the nucleus. Co-treatment with NF-kappaB inhibitors reduced the cisplatin-induced apoptosis of HEI-OC1 cells.
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Seok Choi H, Joo Park K, Chul Hwang S, Yi Park H, Sun Kim Y, Park K. The role of peroxiredoxin III in the ototoxic drug-induced mitochondrial apoptosis of cochlear hair cells. Acta Otolaryngol 2008; 128:944-51. [PMID: 19086304 DOI: 10.1080/00016480701805463] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
CONCLUSION Peroxiredoxin (Prx) III plays a protective role in cisplatin- and gentamicin-induced apoptosis via a mitochondria-dependent pathway in cochlear hair cells. OBJECTIVES The aim of the present study was to investigate the effects of the depletion of endogenous Prx III on oxidative damage to mitochondrial components and on apoptotic events with the use of RNA interference. MATERIALS AND METHOD . Depletion of Prx III was done by RNA interference in cochlear hair cells (UB/OC-1), and cells were exposed to ototoxic drugs (cisplatin or gentamicin). We then compared the apoptotic signaling between Prx III-depleted and control cells. RESULTS The depletion of Prx III resulted in increased intracellular ROS levels accompanied by enhanced apoptosis by ototoxic drugs. The Prx III-depleted cells showed mitochondrial membrane potential collapse, cytochrome c release, and caspase activation.
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Low WK, Sun L, Tan MG, Chua AW, Wang DY. L-N-Acetylcysteine protects against radiation-induced apoptosis in a cochlear cell line. Acta Otolaryngol 2008; 128:440-5. [PMID: 18368580 DOI: 10.1080/00016480701762490] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
CONCLUSION L-N-Acetylcysteine (L-NAC) significantly reduced reactive oxygen species (ROS) generation and cochlear cell apoptosis after irradiation. The safe and effective use of L-NAC in reducing radiation-induced sensorineural hearing loss (SNHL) should be verified by further in vivo studies. OBJECTIVES Radiation-induced SNHL is a common complication after radiotherapy of head and neck tumours. There is growing evidence to suggest that ROS play an important role in apoptotic cochlear cell death from ototoxicity, resulting in SNHL. The aim of this study was to evaluate the effectiveness of L-NAC, an antioxidant, on radiation-induced apoptosis in cochlear cells. MATERIALS AND METHODS The OC-k3 cochlear cell line was studied after 0 and 20 Gy of gamma-irradiation. Cell viability assay was performed using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide. Flow cytometry and TUNEL assay were done with and without the addition of 10 mmol/L of L-NAC. Intracellular generation of ROS was detected by 2',7'-dichlorofluorescein diacetate, with comparisons made using fluorescence intensity. RESULTS L-NAC increased the viability of cells after irradiation. Generation of ROS was demonstrated at 1 h post-irradiation and was significantly reduced by L-NAC (p<0.0001). Flow cytometry and TUNEL assay showed cell apoptosis at 72 h post-irradiation, which was diminished by the addition of L-NAC.
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Whole organ culture of the postnatal sensory inner ear in simulated microgravity. J Neurosci Methods 2008; 171:60-71. [PMID: 18440073 DOI: 10.1016/j.jneumeth.2008.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 01/16/2008] [Accepted: 02/04/2008] [Indexed: 11/23/2022]
Abstract
Among the three major biological in vitro models, cell culture, tissue culture, and organ culture, the latter provides the closest approximation to the in vivo situation, but also requires the most demanding culture conditions. Due to its small size and complex tissue architecture, the mammalian inner ear provides a particular challenge to the development of whole organ culture. Using a rotating bioreactor system with simulated microgravity conditions, the entire mouse inner ear organ can be maintained in culture for up to seven days with preservation of sensory organ morphology and robust marker protein expression in sensory hair cells. Controlled sensory cell lesions can be induced by the ototoxic agent, neomycin sulphate, as a toxicologic model of hair cell degeneration and hair cell loss. The results demonstrate that simulated microgravity organ culture of the inner ear affords an in vitro model for the investigation of developmental, regulatory, and differentiation processes, as well as toxicological, biotechnological, and pharmaceutical screening applications within the normal and pathologic sensory hearing organ.
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Previati M, Lanzoni I, Astolfi L, Fagioli F, Vecchiati G, Pagnoni A, Martini A, Capitani S. Cisplatin cytotoxicity in organ of corti-derived immortalized cells. J Cell Biochem 2007; 101:1185-97. [PMID: 17243113 DOI: 10.1002/jcb.21239] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cisplatin is an anticancer drug currently used in the treatment of genital and head and neck tumors. Its use in these and other types of tumors is narrowed by onset of chemoresistance and severe undesired side effects, like as nephro- and ototoxicity, whose mechanisms of action are only partially understood. In the present study we investigated the effects of cisplatin (cis-dichlorodiaminoplatin, CDDP) on a cell line (OC-k3) developed from organs of Corti of transgenic mice. We observed at 48 h that cell death due to cisplatin was time and concentration-dependent. The cell death displayed some morphological hallmarks of apoptosis, including nuclear fragmentation into several large nuclear fragments, surrounded by a rearranged and thickened actin cytoskeleton. No DNA laddering was detected, suggesting absence of endonuclease activity, nor annexin V positivity, suggesting absence of phosphatidylserine externalization. Several molecules protected the cells against CDDP induced cytotoxicity, including methionine, suramin and PD98059. Methionine reduced CDDP-uptake, while suramin, a polycathionic compound a specifically binding external proteins, did not. This finding suggested that suramin could exert its protective effect by acting on an intracellular transduction pathway. We tested this hypothesis by studying the effect of suramin and PD98059, a MEK inhibitor, on the mitogen activated protein kinase (MAPK) cascade. After CDDP treatment, we found an increase of phosphorylation of extracellular regulated kinases (ERK)1/2, that could be inhibited by PD98059 and suramin. These data suggest that ERK pathways can play a role in mediating the cell death induction in presence of a CDDP challenge.
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Affiliation(s)
- Maurizio Previati
- Department of Morphology and Embryology, Human Anatomy Division, University of Ferrara, Ferrara, Italy.
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Low WK, Tan MGK, Sun L, Chua AWC, Goh LK, Wang DY. Dose-dependant radiation-induced apoptosis in a cochlear cell-line. Apoptosis 2006; 11:2127-36. [PMID: 17051332 DOI: 10.1007/s10495-006-0285-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cisplatin and gentamycin are both ototoxic and they have been shown to induce cochlear cell apoptosis. Although radiation is also ototoxic, radiation-induced apoptosis in cochlear cells has not been studied. This study aimed to investigate the biophysical changes of dose-related radiation-induced cochlear cell apoptosis in an experimental model. Post gamma-irradiation apoptosis was demonstrated in the cochlear cell-line OC-k3 by flow cytometry and TUNEL assay. This was dose-dependant with enhanced apoptosis resulting after 20 than 5 Gy, and occurred predominantly at 72 h post-irradiation. Microarray analysis showed associated dose-dependant apoptotic gene regulation changes. Western blotting revealed p53 up-regulation of at 72 h and phosphorylation at 3, 24, 48 and 72 h after irradiation. Early activation of c-jun occurred at 3 h, but was not sustained with time. Associated dose-dependant intracellular generation of reactive oxygen species (ROS) was also demonstrated using 2', 7'-dichlorofluorescein diacetate. In conclusion, this study demonstrated a dose-dependant cochlear cell apoptosis and associated ROS generation after irradiation, with p53 possibly playing a key role. Based on this ROS-linked apoptotic model, anti-oxidants and anti-apoptotic factors could potentially be used to prevent radiation-induced sensori-neural hearing loss. As these medications can be delivered topically through the middle ear, their systematic side effects could therefore be minimized.
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Affiliation(s)
- Wong-Kein Low
- Department of Otolaryngology, Singapore General Hospital, Singapore, 169608, Singapore.
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36
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Manji SSM, Sørensen BS, Klockars T, Lam T, Hutchison W, Dahl HHM. Molecular characterization and expression of maternally expressed gene 3 (Meg3/Gtl2) RNA in the mouse inner ear. J Neurosci Res 2006; 83:181-90. [PMID: 16342203 DOI: 10.1002/jnr.20721] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The pathways responsible for sound perception in the cochlea involve the coordinated and regulated expression of hundreds of genes. By using microarray analysis, we identified several transcripts enriched in the inner ear, including the maternally expressed gene 3 (Meg3/Gtl2), an imprinted noncoding RNA. Real-time PCR analysis demonstrated that Meg3/Gtl2 was highly expressed in the cochlea, brain, and eye. Molecular studies revealed the presence of several Meg3/Gtl2 RNA splice variants in the mouse cochlea, brain, and eye. In situ hybridizations showed intense Meg3/Gtl2 RNA staining in the nuclei of type I spiral ganglion cells and in cerebellum near the dorsal vestibular region of the cochlea. In embryonic mouse head sections, Meg3/Gtl2 RNA expression was observed in the otocyst, brain, eye, cartilage, connective tissue, and muscle. Meg3/Gtl2 RNA expression increased in the developing otocyst and localized to the spiral ganglion, stria vascularis, Reissner's membrane, and greater epithelial ridge (GER) in the cochlear duct. RT-PCR analysis performed on cell lines derived from the organ of Corti, representing neural, supporting, and hair cells, showed significantly elevated levels of Meg3/Gtl2 expression in differentiated neural cells. We propose that Meg3/Gtl2 RNA functions as a noncoding regulatory RNA in the inner ear and that it plays a role in pattern specification and differentiation of cells during otocyst development, as well as in the maintenance of a number of terminally differentiated cochlear cell types.
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Affiliation(s)
- Shehnaaz S M Manji
- Gene Identification and Expression, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia.
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Mukherjea D, Whitworth CA, Nandish S, Dunaway GA, Rybak LP, Ramkumar V. Expression of the kidney injury molecule 1 in the rat cochlea and induction by cisplatin. Neuroscience 2006; 139:733-40. [PMID: 16464536 DOI: 10.1016/j.neuroscience.2005.12.044] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Revised: 12/16/2005] [Accepted: 12/22/2005] [Indexed: 11/29/2022]
Abstract
Cisplatin is a widely used chemotherapeutic agent whose dose-limiting side effects include ototoxicity and nephrotoxicity. Recent evidence indicates that cisplatin induces the expression of a novel protein, kidney injury molecule-1, in the renal proximal tubular epithelium to aid in regeneration. In this study, we determined whether kidney injury molecule-1 is expressed in the cochlea and is induced by cisplatin. Using reverse transcriptase polymerase chain reaction techniques, we have now identified kidney injury molecule-1 in the rat cochlea and in three different mouse transformed hair cell lines. Administration of cisplatin to rats produced hearing loss and induced kidney injury molecule-1 mRNA in the rat cochlea. Pretreatment of rats with lipoic acid, a scavenger of reactive oxygen species, significantly reduced cisplatin-induced hearing loss and kidney injury molecule-1 expression. Cisplatin also increased the expression of cochlear NOX3 mRNA, a member of the superoxide generating NADPH oxidase family of proteins recently identified in the cochlea, inhibition of which decreased kidney injury molecule-1 expression. Polymerase chain reaction performed on different regions of the cochlea indicated the presence of kidney injury molecule-1 mRNA in the lateral wall, organ of Corti and spiral ganglion. This distribution was confirmed by immunocytochemistry. Taken together, these data identify kidney injury molecule-1 as a novel cochlear injury molecule, whose expression is regulated by reactive oxygen species generated via the NADPH oxidase pathway.
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Affiliation(s)
- D Mukherjea
- Department of Pharmacology, Southern Illinois University School of Medicine, PO Box 19629, Springfield, IL 62794-9626, USA
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38
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Sekiya T, Kojima K, Matsumoto M, Kim TS, Tamura T, Ito J. Cell transplantation to the auditory nerve and cochlear duct. Exp Neurol 2005; 198:12-24. [PMID: 16376874 DOI: 10.1016/j.expneurol.2005.11.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 10/22/2005] [Accepted: 11/04/2005] [Indexed: 12/31/2022]
Abstract
We have developed a technique to deliver cells to the inner ear without injuring the membranes that seal the endolymphatic and perilymphatic chambers. The integrity of these membranes is essential for normal hearing, and the technique should significantly reduce surgical trauma during cell transplantation. Embryonic stem cells transplanted at the internal auditory meatal portion of an atrophic auditory nerve migrated extensively along it. Four-five weeks after transplantation, the cells were found not only throughout the auditory nerve, but also in Rosenthal's canal and the scala media, the most distal portion of the auditory nervous system where the hair cells reside. Migration of the transplanted cells was more extensive following damage to the auditory nerve. In the undamaged nerve, migration was more limited, but the cells showed more signs of neuronal differentiation. This highlights an important balance between tissue damage and the potential for repair.
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Affiliation(s)
- Tetsuji Sekiya
- Department of Otolaryngology-Head and Neck Surgery, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8507, Japan.
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Holley MC. Keynote review: The auditory system, hearing loss and potential targets for drug development. Drug Discov Today 2005; 10:1269-82. [PMID: 16214671 DOI: 10.1016/s1359-6446(05)03595-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
There is a huge potential market for the treatment of hearing loss. Drugs are already available to ameliorate predictable, damaging effects of excessive noise and ototoxic drugs. The biggest challenge now is to develop drug-based treatments for regeneration of sensory cells following noise-induced and age-related hearing loss. This requires careful consideration of the physiological mechanisms of hearing loss and identification of key cellular and molecular targets. There are many molecular cues for the discovery of suitable drug targets and a full range of experimental resources are available for initial screening through to functional analysis in vivo. There is now an unparalleled opportunity for translational research.
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Affiliation(s)
- Matthew C Holley
- Department of Biomedical Sciences, Addison Building, Western Bank, Sheffield S10 2TN, UK.
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Lawoko-Kerali G, Milo M, Davies D, Halsall A, Helyer R, Johnson CM, Rivolta MN, Tones MA, Holley MC. Ventral otic cell lines as developmental models of auditory epithelial and neural precursors. Dev Dyn 2005; 231:801-14. [PMID: 15499550 DOI: 10.1002/dvdy.20187] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Conditionally immortal cell lines were established from the ventral otocyst of the Immortomouse at embryonic day 10.5 and selected to represent precursors of auditory sensory neural and epithelial cells. Selection was based upon dissection, tissue-specific markers, and expression of the transcription factor GATA3. Two cell lines expressed GATA3 but possessed intrinsically different genetic programs under differentiating conditions. US/VOT-E36 represented epithelial progenitors with potential to differentiate into sensory and nonsensory epithelial cells. US/VOT-N33 represented migrating neuroblasts. Under differentiating conditions in vitro the cell lines expressed very different gene expression profiles. Expression of several cell- and tissue-specific markers, including the transcription factors Pax2, GATA3, and NeuroD, differed between the cell lines in a pattern consistent with that observed between their counterparts in vivo. We suggest that these and other conditionally immortal cell lines can be used to study transient events in development against different backgrounds of cell competence.
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Affiliation(s)
- G Lawoko-Kerali
- Department of Biomedical Sciences, Addison Building, Western Bank, Sheffield, United Kingdom
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41
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Dance AL, Miller M, Seragaki S, Aryal P, White B, Aschenbrenner L, Hasson T. Regulation of myosin-VI targeting to endocytic compartments. Traffic 2005; 5:798-813. [PMID: 15355515 DOI: 10.1111/j.1600-0854.2004.00224.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Myosin-VI has been implicated in endocytic trafficking at both the clathrin-coated and uncoated vesicle stages. The identification of alternative splice forms led to the suggestion that splicing defines the vesicle type to which myosin-VI is recruited. In contrast to this hypothesis, we find that in all cell types examined, myosin-VI is associated with uncoated endocytic vesicles, regardless of splice form. GIPC, a PDZ-domain containing adapter protein, co-assembles with myosin-VI on these vesicles. Myosin-VI is only recruited to clathrin-coated vesicles in cells that express high levels of Dab2, a clathrin-binding adapter protein. Overexpression of Dab2 is sufficient to reroute myosin-VI to clathrin-coated pits in cells where myosin-VI is normally associated with uncoated vesicles. In normal rat kidney (NRK) cells, which express high endogenous levels of Dab2, splicing of the globular tail domain further modulates targeting of ectopically expressed myosin-VI. Although myosin-VI can be recruited to clathrin-coated pits, we find no requirement for myosin-VI motor activity in endocytosis in NRK cells. Instead, our data suggest that myosin-VI recruitment to clathrin-coated pits may be an early step in the recruitment of GIPC to the vesicle surface.
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Affiliation(s)
- Amber L Dance
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093, USA
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Zhai S, Shi L, Wang BE, Zheng G, Song W, Hu Y, Gao WQ. Isolation and culture of hair cell progenitors from postnatal rat cochleae. ACTA ACUST UNITED AC 2005; 65:282-93. [DOI: 10.1002/neu.20190] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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43
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Germiller JA, Smiley EC, Ellis AD, Hoff JS, Deshmukh I, Allen SJ, Barald KF. Molecular characterization of conditionally immortalized cell lines derived from mouse early embryonic inner ear. Dev Dyn 2004; 231:815-27. [PMID: 15517566 DOI: 10.1002/dvdy.20186] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Inner ear sensory hair cells (HCs), supporting cells (SCs), and sensory neurons (SNs) are hypothesized to develop from common progenitors in the early embryonic otocyst. Because little is known about the molecular signals that control this lineage specification, we derived a model system of early otic development: conditionally immortalized otocyst (IMO) cell lines from the embryonic day 9.5 Immortomouse. This age is the earliest stage at which the otocyst can easily be separated from surrounding mesenchymal, nervous system, and epithelial cells. At 9.5 days post coitum, there are still pluripotent cells in the otocyst, allowing for the eventual identification of both SN and HC precursors--and possibly an elusive inner ear stem cell. Cell lines derived from primitive precursor cells can also be used as blank canvases for transfections of genes that can affect lineage decisions as the cells differentiate. It is important, therefore, to characterize the "baseline state" of these cell lines in as much detail as possible. We characterized seven representative "precursor-like" IMO cell populations and the uncloned IMO cells, before cell sorting, at the molecular level by polymerase chain reaction (PCR) and immunocytochemistry (IHC), and one line (IMO-2B1) in detail by real-time quantitative PCR and IHC. Many of the phenotypic markers characteristic of differentiated HCs or SCs were detected in IMO-2B1 proliferating cells, as well as during differentiation for up to 30 days in culture. These IMO cell lines represent a unique model system for studying early stages of inner ear development and determining the consequences of affecting key molecular events in their differentiation.
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Affiliation(s)
- John A Germiller
- Department of Cell and Developmental Biology, Program in Cell and Molecular Biology, Program in Neuroscience, University of Michigan, Ann Arbor, Michigan 48109-0616, USA
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Lawoko-Kerali G, Rivolta MN, Lawlor P, Cacciabue-Rivolta DI, Langton-Hewer C, van Doorninck JH, Holley MC. GATA3 and NeuroD distinguish auditory and vestibular neurons during development of the mammalian inner ear. Mech Dev 2004; 121:287-99. [PMID: 15003631 DOI: 10.1016/j.mod.2003.12.006] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2003] [Revised: 12/18/2003] [Accepted: 12/25/2003] [Indexed: 10/26/2022]
Abstract
The function of the zinc finger transcription factor GATA3 was studied in a newly established, conditionally immortal cell line derived to represent auditory sensory neuroblasts migrating from the mouse otic vesicle at embryonic day E10.5. The cell line, US/VOT-33, expressed GATA3, the bHLH transcription factor NeuroD and the POU-domain transcription factor Brn3a, as do auditory neuroblasts in vivo. When GATA3 was knocked down reversibly with antisense oligonucleotides, NeuroD was reversibly down-regulated. Auditory and vestibular neurons form from neuroblasts that express NeuroD and that migrate from the antero-ventral, otic epithelium at E9.5-10.5. On the medial side, neuroblasts and epithelial cells express GATA3 but on the lateral side they do not. At E13.5 most auditory neurons express GATA3 but no longer express NeuroD, whereas vestibular neurons express NeuroD but not GATA3. Neuroblasts expressing NeuroD and GATA3 were located in the ventral, otic epithelium, the adjacent mesenchyme and the developing auditory ganglion. The results suggest that auditory and vestibular neurons arise from different, otic epithelial domains and that they gain their identity prior to migration. In auditory neuroblasts, NeuroD appears to be dependent on the expression of GATA3.
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MESH Headings
- Animals
- Basic Helix-Loop-Helix Transcription Factors
- Cell Differentiation
- Cell Line
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- DNA-Binding Proteins/physiology
- Ear, Inner/cytology
- Ear, Inner/embryology
- Female
- GATA3 Transcription Factor
- Gene Expression Regulation, Developmental
- Immunohistochemistry
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Nerve Tissue Proteins/physiology
- Neurons, Afferent/cytology
- Neurons, Afferent/metabolism
- Oligonucleotides, Antisense/pharmacology
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Trans-Activators/physiology
- Vestibule, Labyrinth/cytology
- Vestibule, Labyrinth/embryology
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Affiliation(s)
- Grace Lawoko-Kerali
- Department of Biomedical Sciences, Institute of Molecular Physiology, Addison Building, Western Bank, Sheffield S10 2TN, UK
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45
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Previati M, Lanzoni I, Corbacella E, Magosso S, Giuffrè S, Francioso F, Arcelli D, Volinia S, Barbieri A, Hatzopoulos S, Capitani S, Martini A. RNA expression induced by cisplatin in an organ of Corti-derived immortalized cell line. Hear Res 2004; 196:8-18. [PMID: 15464296 DOI: 10.1016/j.heares.2004.04.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2003] [Accepted: 04/06/2004] [Indexed: 10/26/2022]
Abstract
Cisplatin [cis-diamminedichloroplatinum(II)] (CDDP) is an organic compound that is widely used for the treatment of a large number of tumors. Its clinical use is limited by the presence of some undesired side effects, like as oto- and nephro toxicity, whose mechanisms of action are not understood. One of the possible CDDP toxicity mechanism seems to involve the generation of reactive oxygen species (ROS), that can impair morphology and function of hair cells (HC) in the organ of Corti. To test this hypothesis we evaluated the effect of CDDP treatment on RNA steady-state levels of 15,000 genes by microarray analysis, using, as a experimental model, the OC-k3 cell line, obtained from the organ of Corti of transgenic mice and constitutively expressing the large SV40 T antigen. We have found overexpression of several genes related to arachidonate mobilization including phospholipase A2, group IV and V, phospholipase A2 activating protein and lysophospholipase I and III, as well as lipoxygenation like arachidonate 12-lipoxygenase and arachidonate 5-lipoxygenase activating protein. In addition, we found significant transcription of genes regulating cell respiration, including cyt c oxidase, as well as genes involved in xenobiotic detoxification and lipid peroxidation such as cyt P450, and other oxidases including spermine oxidase and monoamine oxidase. As a whole, overexpression of the group of different genes seems to indicate that an oxidative burst could take place during cisplatin administration. We therefore searched for evidences of superoxide anion and hydrogen peroxide by means of electron paramagnetic resonance (EPR) spectroscopy and flow cytometry, but failed to detect them. On the other hand, we found an increase of malondialdehyde (MDA) synthesis and protein carbonylation products, indicating the occurence of lipid peroxidative degradation. When we tested the effectiveness of butylated hydroxytoluene (BHT), dithiothreitol (DTT) and N-acetylcysteine (N-Ac) as cytoprotectants, all of them reduced protein carbonylation to control levels and significantly protected OC-k3 from CDDP-induced cell death, with an higher protection when using the lipophylic antioxidant BHT. The same antioxidants prevented also the onset of protein carbonylation, which extent was decreased to basal levels. These data indicate that CDDP is able to stimulate gene expression up to 12 h after the beginning of the treatment. This increase in gene transcription involves a large number of genes potentially able to increase the level of cell ROS. Consistently, cells survival is improved by cotreatment with antioxidants, in particular lipophilics.
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Affiliation(s)
- Maurizio Previati
- Department of Morphology and Embryology, Human Anatomy Division, Ferrara University Via Fossato di Mortara 66, 44100 Ferrara, Italy.
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46
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Kim TS, Kojima K, Nishida AT, Tashiro K, Lee JE, Fujino K, Nakagawa T, Naito Y, Omori K, Lefebvre P, Ito J. Expression of calretinin by fetal otocyst cells after transplantation into damaged rat utricle explants. Acta Otolaryngol 2004:34-8. [PMID: 15078075 DOI: 10.1080/03655230310016771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Severe damage by acoustic overstimulation or ototoxins induces inner ear hair cell loss, resulting in permanent hearing loss and balance disorders because hair cell regeneration scarcely occurs in the inner ear sensory organs of mammals. In this study, to evaluate the possibilities of cell transplantation therapy for damaged inner ear sensory organs, dissociated cell cultures of fetal otocyst cells (FOCs) were established from embryonic day 12.5 (E12.5) rat inner ears, and transplanted into gentamicin-treated explants of vestibular sensory epithelia. Two weeks after transplantation, immunohistochemical analysis demonstrated that some of the grafted FOCs survived within the vestibular sensory epithelia and expressed epitopes of calretinin. one of the hair cell marker proteins. These findings indicate that FOCs have the potential to migrate into damaged vestibular epithelia and differentiate into hair cell immunophenotypes. Cell transplantation therapy may be available for functional regeneration in inner ear diseases.
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Affiliation(s)
- Tae-Soo Kim
- Department of Otolaryngology--Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Kojima K, Takebayashi S, Nakagawa T, Iwai K, Ito J. Nestin expression in the developing rat cochlea sensory epithelia. Acta Otolaryngol 2004:14-7. [PMID: 15078070 DOI: 10.1080/03655230310016744] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
An intermediate filament (IF), nestin, is used as an immature cell marker because nestin occurs in neural progenitors during early development. Recent cell culture studies have indicated that proliferating otic progenitor cells express nestin in vitro. However, localization of nestin in the developing inner ear has not yet been clarified. In this study, the ontogenetical expression of nestin epitopes in the rat cochlea was examined immunohistochemically. Sensory epithelial cells in the rat Corti organ (e.g. hair cells and support cells) transiently demonstrated immunoreactivity for nestin during the late embryonic period. After birth, nestin expression in the sensory epithelia disappeared gradually. The findings of this study indicate that the expression of nestin epitopes in the developing cochlea is linked with the plasticities of sensory epithelial cells, such as proliferation or differentiation.
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Affiliation(s)
- Ken Kojima
- Department of Otolaryngology--Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Ozeki M, Duan L, Hamajima Y, Obritch W, Edson-Herzovi D, Lin J. Establishment and characterization of rat progenitor hair cell lines. Hear Res 2003; 179:43-52. [PMID: 12742237 DOI: 10.1016/s0378-5955(03)00077-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cochlear progenitor hair cell lines are useful for studies of cellular specification, gene expression features, and signal transduction involved in the development of hair cells. To obtain embryonic and postnatal cochlear progenitor hair cell lines, we immortalized primary cultures of sensorineural epithelial cells from otocysts on embryonic day 12 (E12) and explants of the organ of Corti tissues on postnatal day 5 (P5). Primary cultures and explants were then transduced by the E6/E7 genes of human papilloma virus type 16. Transduced cells were passed for >50 passages and partial clonal cells were isolated from the above P5 organ of Corti explants by limiting dilution. The expression of neuronal, neural, epithelial, hair cell markers, and important transcription factors were then examined in these cell clones. Clones that express the above markers were considered as being progenitor hair cells. At least two representative cell lines, one from a mixed culture of otocyst epithelial cells and the other from the organ of Corti cells, ultimately expressed hair cell markers and neuronal/neural cell markers. The former only expressed the early hair cell marker oncomodulin and myosin VIIa, whereas the latter expressed oncomodulin, calretinin, myosin VIIa and Brn 3.1. These cell lines may represent progenitor hair cells at the different stages of cochlear development.
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Affiliation(s)
- Masashi Ozeki
- Department of Otolaryngology, University of Minnesota Medical School, University of Minnesota, 2001 Sixth Street S.E., 216 Lions Research Building, Minneapolis, MN 55455, USA
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Devarajan P, Savoca M, Castaneda MP, Park MS, Esteban-Cruciani N, Kalinec G, Kalinec F. Cisplatin-induced apoptosis in auditory cells: role of death receptor and mitochondrial pathways. Hear Res 2002; 174:45-54. [PMID: 12433395 DOI: 10.1016/s0378-5955(02)00634-2] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Cisplatin, a commonly used chemotherapeutic agent, has a major limitation due to its ototoxicity. Previous studies have shown that cisplatin induces apoptosis in auditory sensory cells, but the underlying mechanisms remain to be elucidated. In this study, cisplatin was found to induce apoptosis in a cochlear cell line, in a dose- and duration-dependent manner. Specific caspase assays revealed an early (6 h) but transient increase in caspase 8 activity, and a delayed (12 h) increase in caspase 9 activity. The enhanced caspase 8 activity was preceded by upregulation of p53 expression, and coincided with cleavage of Bid to its truncated form. This was followed temporally by activation and mitochondrial translocation of Bax, induction of mitochondrial permeability transition, release of cytochrome c into the cytosol, activation of caspase 9, and entry into the execution phase of apoptosis. Our results indicate the involvement of both the death receptor mechanisms as well as mitochondrial pathways in cisplatin-induced apoptosis of auditory cells in an in vitro model system.
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Affiliation(s)
- Prasad Devarajan
- Division of Nephrology, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY 10467, USA.
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Abstract
Cell lines have provided important experimental tools that have enhanced our understanding of neural and sensory function. They are particularly valuable in inner ear research because the auditory and vestibular systems are small, complex, and encased in several layers of bone. Organotypic cultures provide an invaluable experimental resource but require repeated microdissection and culture, and remain complex in terms of cell types and states of differentiation. A number of laboratories have established cell lines that offer a range of potential applications to hearing research. This review describes the advances that have already been made with these lines and the potential applications that they offer in the future. The majority of the cell lines are immortalized with a conditionally expressed, temperature sensitive variant of the SV40 tumor antigen. We discuss the value of these cells in developmental studies.
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Affiliation(s)
- Marcelo N Rivolta
- Department of Biomedical Science, Institute of Molecular Physiology, University of Sheffield, Alfred Denny Building, Western Bank, Sheffield, S10 2TN, United Kingdom.
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