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Benkafadar N, Sato MP, Ling AH, Janesick A, Scheibinger M, Jan TA, Heller S. An essential signaling cascade for avian auditory hair cell regeneration. Dev Cell 2024; 59:280-291.e5. [PMID: 38128539 DOI: 10.1016/j.devcel.2023.11.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 09/27/2023] [Accepted: 11/30/2023] [Indexed: 12/23/2023]
Abstract
Hearing loss is a chronic disease affecting millions of people worldwide, yet no restorative treatment options are available. Although non-mammalian species can regenerate their auditory sensory hair cells, mammals cannot. Birds retain facultative stem cells known as supporting cells that engage in proliferative regeneration when surrounding hair cells die. Here, we investigated gene expression changes in chicken supporting cells during auditory hair cell death. This identified a pathway involving the receptor F2RL1, HBEGF, EGFR, and ERK signaling. We propose a cascade starting with the proteolytic activation of F2RL1, followed by matrix-metalloprotease-mediated HBEGF shedding, and culminating in EGFR-mediated ERK signaling. Each component of this cascade is essential for supporting cell S-phase entry in vivo and is integral for hair cell regeneration. Furthermore, STAT3-phosphorylation converges with this signaling toward upregulation of transcription factors ATF3, FOSL2, and CREM. Our findings could provide a basis for designing treatments for hearing and balance disorders.
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Affiliation(s)
- Nesrine Benkafadar
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Mitsuo P Sato
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Angela H Ling
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Amanda Janesick
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mirko Scheibinger
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Taha A Jan
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Stefan Heller
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Okhovat M, VanCampen J, Nevonen KA, Harshman L, Li W, Layman CE, Ward S, Herrera J, Wells J, Sheng RR, Mao Y, Ndjamen B, Lima AC, Vigh-Conrad KA, Stendahl AM, Yang R, Fedorov L, Matthews IR, Easow SA, Chan DK, Jan TA, Eichler EE, Rugonyi S, Conrad DF, Ahituv N, Carbone L. TAD evolutionary and functional characterization reveals diversity in mammalian TAD boundary properties and function. Nat Commun 2023; 14:8111. [PMID: 38062027 PMCID: PMC10703881 DOI: 10.1038/s41467-023-43841-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
Topological associating domains (TADs) are self-interacting genomic units crucial for shaping gene regulation patterns. Despite their importance, the extent of their evolutionary conservation and its functional implications remain largely unknown. In this study, we generate Hi-C and ChIP-seq data and compare TAD organization across four primate and four rodent species and characterize the genetic and epigenetic properties of TAD boundaries in correspondence to their evolutionary conservation. We find 14% of all human TAD boundaries to be shared among all eight species (ultraconserved), while 15% are human-specific. Ultraconserved TAD boundaries have stronger insulation strength, CTCF binding, and enrichment of older retrotransposons compared to species-specific boundaries. CRISPR-Cas9 knockouts of an ultraconserved boundary in a mouse model lead to tissue-specific gene expression changes and morphological phenotypes. Deletion of a human-specific boundary near the autism-related AUTS2 gene results in the upregulation of this gene in neurons. Overall, our study provides pertinent TAD boundary evolutionary conservation annotations and showcases the functional importance of TAD evolution.
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Affiliation(s)
- Mariam Okhovat
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA.
| | - Jake VanCampen
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Kimberly A Nevonen
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Lana Harshman
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Weiyu Li
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Cora E Layman
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Samantha Ward
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Jarod Herrera
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Jackson Wells
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Rory R Sheng
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Yafei Mao
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China
| | - Blaise Ndjamen
- Histology and Light Microscopy Core Facility, Gladstone Institutes, San Francisco, CA, USA
| | - Ana C Lima
- Division of Genetics, Oregon National Primate Research Center, Beaverton, OR, USA
| | | | - Alexandra M Stendahl
- Division of Genetics, Oregon National Primate Research Center, Beaverton, OR, USA
| | - Ran Yang
- Division of Genetics, Oregon National Primate Research Center, Beaverton, OR, USA
| | - Lev Fedorov
- OHSU Transgenic Mouse Models Core Lab, Oregon Health and Science University, Portland, OR, USA
| | - Ian R Matthews
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, CA, USA
| | - Sarah A Easow
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, CA, USA
| | - Dylan K Chan
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, CA, USA
| | - Taha A Jan
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, 98195, USA
| | - Sandra Rugonyi
- Department of Biomedical Engineering, Oregon Health and Science University, Portland, OR, USA
| | - Donald F Conrad
- Division of Genetics, Oregon National Primate Research Center, Beaverton, OR, USA
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Nadav Ahituv
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA.
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA.
| | - Lucia Carbone
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA.
- Division of Genetics, Oregon National Primate Research Center, Beaverton, OR, USA.
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA.
- Department of Medical Informatics and Clinical Epidemiology, Oregon Health and Science University, Portland, OR, USA.
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Okhovat M, VanCampen J, Lima AC, Nevonen KA, Layman CE, Ward S, Herrera J, Stendahl AM, Yang R, Harshman L, Li W, Sheng RR, Mao Y, Fedorov L, Ndjamen B, Vigh-Conrad KA, Matthews IR, Easow SA, Chan DK, Jan TA, Eichler EE, Rugonyi S, Conrad DF, Ahituv N, Carbone L. TAD Evolutionary and functional characterization reveals diversity in mammalian TAD boundary properties and function. bioRxiv 2023:2023.03.07.531534. [PMID: 36945527 PMCID: PMC10028908 DOI: 10.1101/2023.03.07.531534] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Topological associating domains (TADs) are self-interacting genomic units crucial for shaping gene regulation patterns. Despite their importance, the extent of their evolutionary conservation and its functional implications remain largely unknown. In this study, we generate Hi-C and ChIP-seq data and compare TAD organization across four primate and four rodent species, and characterize the genetic and epigenetic properties of TAD boundaries in correspondence to their evolutionary conservation. We find that only 14% of all human TAD boundaries are shared among all eight species (ultraconserved), while 15% are human-specific. Ultraconserved TAD boundaries have stronger insulation strength, CTCF binding, and enrichment of older retrotransposons, compared to species-specific boundaries. CRISPR-Cas9 knockouts of two ultraconserved boundaries in mouse models leads to tissue-specific gene expression changes and morphological phenotypes. Deletion of a human-specific boundary near the autism-related AUTS2 gene results in upregulation of this gene in neurons. Overall, our study provides pertinent TAD boundary evolutionary conservation annotations, and showcase the functional importance of TAD evolution.
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David AP, Loftus PA, Russell MS, Goldberg AN, El-Sayed IH, Jan TA, Roland LT. RNA Sequencing and Gene Ontology Analysis in Acute Invasive Fungal Sinusitis. Am J Rhinol Allergy 2022; 37:78-82. [DOI: 10.1177/19458924221134732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background Acute invasive fungal sinusitis (AIFS) is an aggressive and dangerous disease of the paranasal sinuses with high morbidity and mortality. The immune response at the level of the nasal mucosa, the site of entry, has not been previously evaluated. Objective To evaluate differential gene expression in the sinonasal mucosa of AIFS patients as compared to control patients using RNA sequencing. Methods Sinonasal tissue samples were prospectively obtained from consenting patients undergoing surgery between November, 2020 and November, 2021. RNA extraction and sequencing were performed and differential expression was analyzed to detect transcriptional differences between patient groups. Results Tissue samples were collected from 4 patients with active AIFS diagnoses, 2 patients with recovered AIFS, 1 patient with a diagnosis of non-invasive fungal ball, and 4 healthy controls. 255 genes were differentially expressed in AIFS patients as compared to control patients. Specific Gene Ontology (GO) biological processes that were identified as differentially expressed in AIFS patients as compared to controls included the following: 1. GO:0007155 (cell adhesion), 2. GO:0030199 (collagen fibril organization) and 3. GO:0001525 (angiogenesis). Conclusion Transcriptional differences were noted between AIFS and control patients in sinonasal tissue samples. Future work is necessary to determine causes of the differential gene expressions between AIFS and control patients, specifically those who are immunosuppressed, or with preexisting non-invasive forms of fungal sinusitis, to guide treatment and prevention strategies.
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Affiliation(s)
- Abel P. David
- Department of Otolaryngology – Head and Neck Surgery, University of California, San Francisco, San Francisco, CA, USA
| | - Patricia A. Loftus
- Department of Otolaryngology – Head and Neck Surgery, University of California, San Francisco, San Francisco, CA, USA
| | - Matthew S. Russell
- Department of Otolaryngology – Head and Neck Surgery, Mass Eye and Ear, Boston, MA, USA
| | - Andrew N. Goldberg
- Department of Otolaryngology – Head and Neck Surgery, University of California, San Francisco, San Francisco, CA, USA
| | - Ivan H. El-Sayed
- Department of Otolaryngology – Head and Neck Surgery, University of California, San Francisco, San Francisco, CA, USA
| | - Taha A. Jan
- Department of Otolaryngology – Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lauren T. Roland
- Department of Otolaryngology – Head and Neck Surgery, Washington University in St Louis, St Louis, MO, USA
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Scheibinger M, Janesick A, Benkafadar N, Ellwanger DC, Jan TA, Heller S. Cell-type identity of the avian utricle. Cell Rep 2022; 40:111432. [PMID: 36170825 PMCID: PMC9588199 DOI: 10.1016/j.celrep.2022.111432] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/18/2022] [Accepted: 09/08/2022] [Indexed: 11/30/2022] Open
Abstract
The avian utricle, a vestibular organ of the inner ear, displays turnover of sensory hair cells throughout life. This is in sharp contrast to the mammalian utricle, which shows limited regenerative capacity. Here, we use single-cell RNA sequencing to identify distinct marker genes for the different sensory hair cell subtypes of the chicken utricle, which we validated in situ. We provide markers for spatially distinct supporting cell populations and identify two transitional cell populations of dedifferentiating supporting cells and developing hair cells. Trajectory reconstruction resulted in an inventory of gene expression dynamics of natural hair cell generation in the avian utricle. Scheibinger et al. provide a single-cell transcriptomic atlas of the chicken utricle, a vestibular organ. Hair cell and supporting cell subtypes are defined by marker genes, and trajectories of gene expression dynamics during hair cell turnover are shown. This resource provides a baseline to study inner ear damage and regeneration.
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Affiliation(s)
- Mirko Scheibinger
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Amanda Janesick
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Nesrine Benkafadar
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Daniel C Ellwanger
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Taha A Jan
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Stefan Heller
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Landegger LD, Fujita T, Jan TA, Varela-Nieto I. Editorial: Otologic Trauma, Pathology, and Therapy. Front Cell Neurosci 2022; 16:900074. [PMID: 35496907 PMCID: PMC9043112 DOI: 10.3389/fncel.2022.900074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 03/25/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Lukas D. Landegger
- Department of Otolaryngology-Head and Neck Surgery, Vienna General Hospital, Medical University of Vienna, Vienna, Austria
- *Correspondence: Lukas D. Landegger
| | - Takeshi Fujita
- Department of Otolaryngology-Head and Neck Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Taha A. Jan
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Isabel Varela-Nieto
- Institute for Biomedical Research “Alberto Sols”, Spanish National Research Council-Autonomous University of Madrid, Madrid, Spain
- Rare Diseases Networking Biomedical Research Centre, CIBER, Carlos III Institute of Health, Madrid, Spain
- La Paz Hospital Institute for Health Research, Madrid, Spain
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Jan TA, Eltawil Y, Ling AH, Chen L, Ellwanger DC, Heller S, Cheng AG. Spatiotemporal dynamics of inner ear sensory and non-sensory cells revealed by single-cell transcriptomics. Cell Rep 2021; 36:109358. [PMID: 34260939 PMCID: PMC8378666 DOI: 10.1016/j.celrep.2021.109358] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 12/25/2020] [Accepted: 06/17/2021] [Indexed: 11/28/2022] Open
Abstract
The utricle is a vestibular sensory organ that requires mechanosensitive hair cells to detect linear acceleration. In neonatal mice, new hair cells are derived from non-sensory supporting cells, yet cell type diversity and mechanisms of cell addition remain poorly characterized. Here, we perform computational analyses on single-cell transcriptomes to categorize cell types and resolve 14 individual sensory and non-sensory subtypes. Along the periphery of the sensory epithelium, we uncover distinct groups of transitional epithelial cells, marked by Islr, Cnmd, and Enpep expression. By reconstructing de novo trajectories and gene dynamics, we show that as the utricle expands, Islr+ transitional epithelial cells exhibit a dynamic and proliferative phase to generate new supporting cells, followed by coordinated differentiation into hair cells. Taken together, our study reveals a sequential and coordinated process by which non-sensory epithelial cells contribute to growth of the postnatal mouse sensory epithelium. The postnatal mouse utricle expands by more than 35% and doubles its number of hair cells during the first 8 days. Using single-cell transcriptomics, Jan et al. show that the surrounding transitional epithelial cells proliferate and contribute to the expansion of the sensory epithelium through a stepwise differentiation mechanism.
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Affiliation(s)
- Taha A Jan
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Palo Alto, CA 94305, USA; Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco, San Francisco, CA 94115, USA
| | - Yasmin Eltawil
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Palo Alto, CA 94305, USA
| | - Angela H Ling
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Palo Alto, CA 94305, USA; Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco, San Francisco, CA 94115, USA
| | - Leon Chen
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Palo Alto, CA 94305, USA
| | - Daniel C Ellwanger
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Palo Alto, CA 94305, USA; Genome Analysis Unit, Amgen Research, Amgen Inc., South San Francisco, CA 94080, USA
| | - Stefan Heller
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Palo Alto, CA 94305, USA.
| | - Alan G Cheng
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Palo Alto, CA 94305, USA.
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Benkafadar N, Janesick A, Scheibinger M, Ling AH, Jan TA, Heller S. Transcriptomic characterization of dying hair cells in the avian cochlea. Cell Rep 2021; 34:108902. [PMID: 33761357 DOI: 10.1016/j.celrep.2021.108902] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 01/11/2021] [Accepted: 03/03/2021] [Indexed: 12/28/2022] Open
Abstract
Sensory hair cells are prone to apoptosis caused by various drugs including aminoglycoside antibiotics. In mammals, this vulnerability results in permanent hearing loss because lost hair cells are not regenerated. Conversely, hair cells regenerate in birds, making the avian inner ear an exquisite model for studying ototoxicity and regeneration. Here, we use single-cell RNA sequencing and trajectory analysis on control and dying hair cells after aminoglycoside treatment. Interestingly, the two major subtypes of avian cochlear hair cells, tall and short hair cells, respond differently. Dying short hair cells show a noticeable transient upregulation of many more genes than tall hair cells. The most prominent gene group identified is associated with potassium ion conductances, suggesting distinct physiological differences. Moreover, the dynamic characterization of >15,000 genes expressed in tall and short avian hair cells during their apoptotic demise comprises a resource for further investigations toward mammalian hair cell protection and hair cell regeneration.
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Affiliation(s)
- Nesrine Benkafadar
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Amanda Janesick
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mirko Scheibinger
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Angela H Ling
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Taha A Jan
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Stefan Heller
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Kubota M, Scheibinger M, Jan TA, Heller S. Greater epithelial ridge cells are the principal organoid-forming progenitors of the mouse cochlea. Cell Rep 2021; 34:108646. [PMID: 33472062 PMCID: PMC7847202 DOI: 10.1016/j.celrep.2020.108646] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 11/01/2020] [Accepted: 12/21/2020] [Indexed: 02/07/2023] Open
Abstract
In mammals, hearing loss is irreversible due to the lack of regenerative potential of non-sensory cochlear cells. Neonatal cochlear cells, however, can grow into organoids that harbor sensory epithelial cells, including hair cells and supporting cells. Here, we purify different cochlear cell types from neonatal mice, validate the composition of the different groups with single-cell RNA sequencing (RNA-seq), and assess the various groups' potential to grow into inner ear organoids. We find that the greater epithelial ridge (GER), a transient cell population that disappears during post-natal cochlear maturation, harbors the most potent organoid-forming cells. We identified three distinct GER cell groups that correlate with a specific spatial distribution of marker genes. Organoid formation was synergistically enhanced when the cells were cultured at increasing density. This effect is not due to diffusible signals but requires direct cell-to-cell contact. Our findings improve the development of cell-based assays to study culture-generated inner ear cell types.
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Affiliation(s)
- Marie Kubota
- Department of Otolaryngology - Head & Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Mirko Scheibinger
- Department of Otolaryngology - Head & Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Taha A Jan
- Department of Otolaryngology - Head & Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Otolaryngology - Head & Neck Surgery, University of California San Francisco, San Francisco, CA 94115, USA
| | - Stefan Heller
- Department of Otolaryngology - Head & Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Jan TA, Remenschneider AK, Halpin C, Seton M, McKenna MJ, Quesnel AM. Third-generation bisphosphonates for cochlear otosclerosis stabilizes sensorineural hearing loss in long-term follow-up. Laryngoscope Investig Otolaryngol 2017; 2:262-268. [PMID: 29094069 PMCID: PMC5655565 DOI: 10.1002/lio2.91] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Revised: 06/12/2017] [Accepted: 07/01/2017] [Indexed: 12/22/2022] Open
Abstract
Objective To assess long‐term hearing outcomes in patients treated with third‐generation bisphosphonates for otosclerosis‐related progressive sensorineural hearing loss (SNHL). Study Design Retrospective case series review Methods We performed a retrospective case series review of patients with otosclerosis and progressive SNHL. Patients were treated with either risedronate or zoledronate after a diagnosis of otosclerosis with a significant SNHL component. Bone conduction pure tone threshold averages (BC‐PTAs) and word recognition scores (WRS) before and after bisphosphonate administration in long‐term follow‐up was analyzed. Significant change in BC‐PTA was defined as greater than 10dB or between 4% and 18% in WRS based on binomial variance. Results Seven patients were identified and 14 ears met inclusion criteria. Three patients were female and the mean age was 48.3 ± 10.3 years. The mean duration between treatment with bisphosphonate administration and long‐term post‐treatment follow‐up audiometry was 87.6 ± 18.3 months, with a range of 61.6 to 109.1 months and median of 89.2 months. Analysis using BC‐PTA and WRS demonstrated that 11 ears remained stable while 2 improved and 1 worsened. No patient experienced any major complication as the result of bisphosphonate therapy. Conclusion Treatment with third‐generation bisphosphonates is associated with stability in otosclerosis‐related sensorineural hearing over 5‐ to 9‐year period. These results suggest that such medications may prevent the progression of SNHL in patients with otosclerosis. Level of Evidence 4 (Case series).
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Affiliation(s)
- Taha A Jan
- Department of Otolaryngology , Massachusetts Eye and Ear Harvard Medical School Boston Massachusetts U.S.A
| | - Aaron K Remenschneider
- Department of Otolaryngology , Massachusetts Eye and Ear Harvard Medical School Boston Massachusetts U.S.A
| | - Christopher Halpin
- Department of Otolaryngology , Massachusetts Eye and Ear Harvard Medical School Boston Massachusetts U.S.A
| | - Margaret Seton
- Department of Medicine , Brigham and Women's Hospital Harvard Medical School Boston Massachusetts U.S.A
| | - Michael J McKenna
- Department of Otolaryngology , Massachusetts Eye and Ear Harvard Medical School Boston Massachusetts U.S.A
| | - Alicia M Quesnel
- Department of Otolaryngology , Massachusetts Eye and Ear Harvard Medical School Boston Massachusetts U.S.A
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Jan TA, Cheng YS, Landegger LD, Lin BM, Srikanth P, Niesten MEF, Lee DJ. Relationship between Surgically Treated Superior Canal Dehiscence Syndrome and Body Mass Index. Otolaryngol Head Neck Surg 2017; 156:722-727. [DOI: 10.1177/0194599816686563] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective Examine the association between body mass index (BMI) and superior canal dehiscence (SCD) among patients who have undergone surgical repair for superior canal dehiscence. Study Design Retrospective comparison study. Setting Neurotology tertiary care center. Subjects and Methods Retrospective review of consecutive adult patients evaluated at our institution for SCD syndrome between November 2006 and August 2015. A control group who underwent imaging within the same period for reasons other than SCD was also included. Patient demographics, weight, and height were examined. We performed multiple subgroup analyses to investigate the relationship of BMI, surgery vs no surgery, and correlation between patient BMI and SCD size. Results Of the 268 patients with SCD, 99 underwent surgery; 96 of these patients had complete medical records and were eligible for inclusion. Eighty-eight patients were noted to have arcuate eminence defects, and the mean BMI of this surgical cohort was 28.09 ± 5.26 kg/m2. Nonsurgically treated patients with SCD with available data (n = 94) had a mean BMI of 27.97 ± 6.95 kg/m2. A control group of 204 patients who underwent computed tomography for non-SCD-related causes was analyzed, of whom 155 had available data with a mean BMI of 27.91 ± 6.38 kg/m2. Conclusion We demonstrate that adult patients who undergo surgery for SCD are not obese (mean BMI <30), and size of dehiscence poorly correlates with BMI. Our observations call into question the proposed theory that patient weight is a risk factor for the development of symptomatic SCD involving the arcuate eminence.
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Affiliation(s)
- Taha A. Jan
- Department of Otolaryngology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - Yew Song Cheng
- Department of Otolaryngology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - Lukas D. Landegger
- Department of Otolaryngology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - Brian M. Lin
- Department of Otolaryngology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - Priya Srikanth
- Department of Otolaryngology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - Marlien E. F. Niesten
- Department of Otorhinolaryngology–Head and Neck Surgery, University Medical Center, Utrecht, the Netherlands
| | - Daniel J. Lee
- Department of Otolaryngology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
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Jan TA, Kozin ED, Kanumuri VV, Sethi RK, Jung DH. Improvement in word recognition following treatment failure for sudden sensorineural hearing loss. World J Otorhinolaryngol Head Neck Surg 2016; 2:168-174. [PMID: 29204563 PMCID: PMC5698528 DOI: 10.1016/j.wjorl.2016.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/20/2016] [Accepted: 06/29/2016] [Indexed: 12/20/2022] Open
Abstract
Objectives Patients with sudden sensorineural hearing loss (SSNHL) may have word recognition scores (WRS) that correlate with pure tone average (PTA). We hypothesize that there is a subset of patients with SSNHL who have improved WRS despite stable PTA. Methods Retrospective case review at a tertiary otolaryngology practice. Results We identified 13 of 113 patients with SSNHL whose WRS increased despite overall stable pure tone averages. There was an observed average improvement in WRS by 23.8 points in this patient cohort at follow-up, with mean initial PTA in the affected ear at 48.7 dB. Conclusions We identify a novel cohort of SSNHL patients that have failed treatment as measured by PTA, but who have increased WRS over time. These data have implications for patient counseling and lend insight into the pathophysiology of SSNHL.
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Affiliation(s)
- Taha A Jan
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Elliott D Kozin
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Vivek V Kanumuri
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Rosh K Sethi
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - David H Jung
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
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Herget M, Scheibinger M, Guo Z, Jan TA, Adams CM, Cheng AG, Heller S. A simple method for purification of vestibular hair cells and non-sensory cells, and application for proteomic analysis. PLoS One 2013; 8:e66026. [PMID: 23750277 PMCID: PMC3672136 DOI: 10.1371/journal.pone.0066026] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 05/07/2013] [Indexed: 11/23/2022] Open
Abstract
Mechanosensitive hair cells and supporting cells comprise the sensory epithelia of the inner ear. The paucity of both cell types has hampered molecular and cell biological studies, which often require large quantities of purified cells. Here, we report a strategy allowing the enrichment of relatively pure populations of vestibular hair cells and non-sensory cells including supporting cells. We utilized specific uptake of fluorescent styryl dyes for labeling of hair cells. Enzymatic isolation and flow cytometry was used to generate pure populations of sensory hair cells and non-sensory cells. We applied mass spectrometry to perform a qualitative high-resolution analysis of the proteomic makeup of both the hair cell and non-sensory cell populations. Our conservative analysis identified more than 600 proteins with a false discovery rate of <3% at the protein level and <1% at the peptide level. Analysis of proteins exclusively detected in either population revealed 64 proteins that were specific to hair cells and 103 proteins that were only detectable in non-sensory cells. Statistical analyses extended these groups by 53 proteins that are strongly upregulated in hair cells versus non-sensory cells and vice versa by 68 proteins. Our results demonstrate that enzymatic dissociation of styryl dye-labeled sensory hair cells and non-sensory cells is a valid method to generate pure enough cell populations for flow cytometry and subsequent molecular analyses.
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Affiliation(s)
- Meike Herget
- Department of Otolaryngology – HNS, Stanford University, Stanford, California, United States of America
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
| | - Mirko Scheibinger
- Department of Otolaryngology – HNS, Stanford University, Stanford, California, United States of America
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
| | - Zhaohua Guo
- Department of Otolaryngology – HNS, Stanford University, Stanford, California, United States of America
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
| | - Taha A. Jan
- Department of Otolaryngology – HNS, Stanford University, Stanford, California, United States of America
| | - Christopher M. Adams
- Mass Spectrometry Core, Stanford University, Stanford, California, United States of America
| | - Alan G. Cheng
- Department of Otolaryngology – HNS, Stanford University, Stanford, California, United States of America
| | - Stefan Heller
- Department of Otolaryngology – HNS, Stanford University, Stanford, California, United States of America
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
- * E-mail:
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14
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Jan TA, Redjal N, Walcott BP, Sheth SA. Intranasal myiasis: a rare complication of transnasal skull base surgery. J Clin Neurosci 2013; 20:1178-80. [PMID: 23669173 DOI: 10.1016/j.jocn.2012.09.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 09/08/2012] [Indexed: 11/28/2022]
Abstract
A 57-year-old woman with a history of atypical intracranial meningioma had undergone multiple craniotomies and endoscopic skull base procedures over several years. She presented most recently with nasal discharge consisting of intranasal larvae. Isolated organisms from the nasal cavity and maxillary sinus were identified as blow fly larvae (Calliphoridae family). The patient was treated with transnasal debridement and antibiotic therapy. The organisms were successfully eradicated and she is free from further signs of infection. Intranasal myiasis is an unusual complication of anterior skull base surgery.
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Affiliation(s)
- Taha A Jan
- Department of Otolaryngology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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Chan DK, Jan TA, Koltai PJ. Effect of Obesity and Medical Comorbidities on Outcomes After Adjunct Surgery for Obstructive Sleep Apnea in Cases of Adenotonsillectomy Failure. ACTA ACUST UNITED AC 2012; 138:891-6. [DOI: 10.1001/2013.jamaoto.197] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Abstract
Isolation of specific cell types allows one to analyze rare cell populations such as stem/progenitor cells. Such an approach to studying inner ear tissues presents a unique challenge because of the paucity of cells of interest and few transgenic reporter mouse models. Here, we describe a protocol using fluorescence-conjugated probes to selectively label LacZ-positive cells from the neonatal cochleae. The most common underlying pathology of sensorineural hearing loss is the irreversible damage and loss of cochlear sensory hair cells, which are required to transduce sound waves to neural impulses. Recent evidence suggests that the murine auditory and vestibular organs harbor stem/progenitor cells that may have regenerative potential. These findings warrant further investigation, including identifying specific cell types with stem/progenitor cell characteristics. The Wnt signaling pathway has been demonstrated to play a critical role in maintaining stem/progenitor cell populations in several organ systems. We have recently identified Wnt-responsive Axin2-expressing cells in the neonatal cochlea, but their function is largely unknown. To better understand the behavior of these Wnt-responsive cells in vitro, we have developed a method of isolating Axin2-expressing cells from cochleae of Axin2-LacZ reporter mice. Using flow cytometry to isolate Axin2-LacZ positive cells from the neonatal cochleae, we could in turn execute a variety of experiments on live cells to interrogate their behavior as stem/progenitor cells. Here, we describe in detail the steps for the microdissection of neonatal cochlea, dissociation of these tissues, labeling of the LacZ-positive cells using a fluorogenic substrate, and cell sorting. Techniques for dissociating cochleae into single cells and isolating cochlear cells via flow cytometry have been described. We have made modifications to these techniques to establish a novel protocol to isolate LacZ-expressing cells from the neonatal cochlea.
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Affiliation(s)
- Taha A Jan
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, CA, USA
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Sinkkonen ST, Chai R, Jan TA, Hartman BH, Laske RD, Gahlen F, Sinkkonen W, Cheng AG, Oshima K, Heller S. Intrinsic regenerative potential of murine cochlear supporting cells. Sci Rep 2011; 1:26. [PMID: 22355545 PMCID: PMC3216513 DOI: 10.1038/srep00026] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 06/17/2011] [Indexed: 12/17/2022] Open
Abstract
The lack of cochlear regenerative potential is the main cause for the permanence of hearing loss. Albeit quiescent in vivo, dissociated non-sensory cells from the neonatal cochlea proliferate and show ability to generate hair cell-like cells in vitro. Only a few non-sensory cell-derived colonies, however, give rise to hair cell-like cells, suggesting that sensory progenitor cells are a subpopulation of proliferating non-sensory cells. Here we purify from the neonatal mouse cochlea four different non-sensory cell populations by fluorescence-activated cell sorting (FACS). All four populations displayed proliferative potential, but only lesser epithelial ridge and supporting cells robustly gave rise to hair cell marker-positive cells. These results suggest that cochlear supporting cells and cells of the lesser epithelial ridge show robust potential to de-differentiate into prosensory cells that proliferate and undergo differentiation in similar fashion to native prosensory cells of the developing inner ear.
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Affiliation(s)
- Saku T Sinkkonen
- Department of Otolaryngology - Head & Neck Surgery, Stanford University School of Medicine, Stanford CA 94305, USA
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Lieberman DM, Jan TA, Ahmad SO, Most SP. Effects of corticosteroids on functional recovery and neuron survival after facial nerve injury in mice. ACTA ACUST UNITED AC 2010; 13:117-24. [PMID: 21079107 DOI: 10.1001/archfacial.2010.98] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVES To assess the effects of corticosteroid administration on functional recovery and cell survival in the facial motor nucleus (FMN) following crush injury in adult and juvenile mice and to evaluate the relationship between functional recovery and facial motoneuron survival. METHODS A prospective blinded analysis of functional recovery and cell survival in the FMN after crush injury in juvenile and adult mice was carried out. All mice underwent a unilateral facial nerve crush injury and received 7 doses of daily injections. Adults received normal saline or low-dose or high-dose corticosteroid treatment. Juveniles received either normal saline or low-dose corticosteroid treatment. Whisker function was monitored to assess functional recovery. Stereologic analysis was performed to determine neuron and glial survival in the FMN following recovery. RESULTS Following facial nerve injury, all adult mice recovered fully, while juvenile mice recovered slower and incompletely. This corresponded to a significantly greater neuron loss in the FMN of juveniles compared with adults. Corticosteroid treatment slowed functional recovery in adult mice. This corresponded with significantly greater neuron loss in the FMN in corticosteroid-treated mice. In juvenile mice, corticosteroid treatment showed a trend, which was significant at several time points, toward a more robust functional recovery compared with controls. CONCLUSIONS Corticosteroid treatment slows functional recovery and impairs neuron survival following facial nerve crush injury in adult mice. The degree of motor neuron survival corresponds with functional status. In juvenile mice, crush injury results in overall poor functional recovery and profound cell loss in the FMN. With low-dose corticosteroid treatment, there is a significantly enhanced functional recovery after injury in these mice (P < .05).
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Affiliation(s)
- David M Lieberman
- Department of Otolaryngology-Head & Neck Surgery, Stanford University, 801 Welch Road, Stanford, CA 94305, USA
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Reiner DJ, Jan TA, Boughter JD, Li CX, Lu L, Williams RW, Waters RS. Genetic analysis of tongue size and taste papillae number and size in recombinant inbred strains of mice. Chem Senses 2008; 33:693-707. [PMID: 18653645 DOI: 10.1093/chemse/bjn025] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Quantitative trait loci (QTLs) analysis has been used to examine natural variation of phenotypes in the mouse somatosensory cortex, hippocampus, cerebellum, and amygdala. QTL analysis has also been utilized to map and identify genes underlying anatomical features such as muscle, organ, and body weights. However, this methodology has not been previously applied to identification of anatomical structures related to gustatory phenotypes. In this study, we used QTL analysis to map and characterize genes underlying tongue size, papillae number, and papillae area. In a set of 43 BXD recombinant inbred (RI) mice (n = 111) and 2 parental strains (C57BL/6J and DBA/2J; n = 7), we measured tongue length, width, and weight. In a subset of 23 BXD RI mice and the parental mice, we measured filiform and fungiform papillae number and fungiform papillae area. Using QTL linkage analysis (through WebQTL), we detected 2 significant and noninteracting QTLs influencing tongue length on chromosomes 5 and 7. We also found a significant QTL on chromosome 19 underlying fungiform papillae area and a suggestive QTL on chromosome 2 linked to fungiform papillae number. From these QTLs, we identified a number of candidate genes within the QTL intervals that include SRY-box containing gene, nebulin-related anchoring protein, and actin-binding LIM protein 1. This study is an important first step in identifying genetic factors underlying tongue size, papillae size, and papillae number using QTL analysis.
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Affiliation(s)
- David J Reiner
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Memphis, TN 38163, USA
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Jan TA, Lu L, Li CX, Williams RW, Waters RS. Genetic analysis of posterior medial barrel subfield (PMBSF) size in somatosensory cortex (SI) in recombinant inbred strains of mice. BMC Neurosci 2008; 9:3. [PMID: 18179704 PMCID: PMC2254631 DOI: 10.1186/1471-2202-9-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Accepted: 01/07/2008] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Quantitative trait locus (QTL) mapping is an important tool for identifying potential candidate genes linked to complex traits. QTL mapping has been used to identify genes associated with cytoarchitecture, cell number, brain size, and brain volume. Previously, QTL mapping was utilized to examine variation of barrel field size in the somatosensory cortex in a limited number of recombinant inbred (RI) strains of mice. In order to further elucidate the underlying natural variation in mouse primary somatosensory cortex, we measured the size of the posterior medial barrel subfield (PMBSF), associated with the representation of the large mystacial vibrissae, in an expanded sample set that included 42 BXD RI strains, two parental strains (C57BL/6J and DBA/2J), and one F1 strain (B6D2F1). Cytochrome oxidase labeling was used to visualize barrels within the PMBSF. RESULTS We observed a 33% difference between the largest and smallest BXD RI strains with continuous variation in-between. Using QTL linkage analysis from WebQTL, we generated linkage maps of raw total PMBSF and brain weight adjusted total PMBSF areas. After removing the effects of brain weight, we detected a suggestive QTL (likelihood ratio statistic [LRS]: 14.20) on the proximal arm of chromosome 4. Candidate genes under the suggestive QTL peak for PMBSF area were selected based on the number of single nucleotide polymorphisms (SNPs) present and the biological relevance of each gene. Among the candidate genes are Car8 and Rab2. More importantly, mRNA expression profiles obtained using GeneNetwork indicated a strong correlation between total PMBSF area and two genes (Adcy1 and Gap43) known to be important in mouse cortex development. GAP43 has been shown to be critical during neurodevelopment of the somatosensory cortex, while knockout Adcy1 mice have disrupted barrel field patterns. CONCLUSION We detected a novel suggestive QTL on chromosome 4 that is linked to PMBSF size. The present study is an important step towards identifying genes underlying the size and possible development of cortical structures.
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Affiliation(s)
- Taha A Jan
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA.
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Oladehin A, Margret CP, Maier SE, Li CX, Jan TA, Chappell TD, Waters RS. Early postnatal alcohol exposure reduced the size of vibrissal barrel field in rat somatosensory cortex (SI) but did not disrupt barrel field organization. Alcohol 2007; 41:253-61. [PMID: 17630086 PMCID: PMC2435073 DOI: 10.1016/j.alcohol.2007.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2007] [Revised: 04/13/2007] [Accepted: 04/13/2007] [Indexed: 12/24/2022]
Abstract
Prenatal alcohol exposure (PAE) has been shown to alter the somatosensory cortex in both human and animal studies. In rodents, PAE reduced the size, but not the pattern of the posteromedial barrel subfield (PMBSF) associated with the representation of the whiskers, in newborn, juvenile, and adult rats. However, the PMBSF is not present at birth, but rather first appears in the middle of the first postnatal week during the brain-growth spurt period. These findings raise questions whether early postnatal alcohol exposure might disrupt both barrel field pattern and size, questions that were investigated in the present study. Newborn Sprague-Dawley rats were assigned into alcohol (Alc), nutritional gastric control (GC), and suckle control (SC) groups on postnatal day 4 (P4). Rat pups in Alc and GC were artificially fed with alcohol and maltose-dextrin dissolved in milk, respectively, via an implant gastrostomy tube, from P4 to P9. Pups in the Alc group received alcohol (6.0 g/kg) in milk, while the GC controls received isocaloric equivalent maltose-dextrin dissolved in milk. Pups in the SC group remained with their mothers and breast fed throughout the experimental period. On P10, pups in each group were weighed, sacrificed, and their brains removed and weighed. Cortical hemispheres were separated, weighed, flattened, sectioned tangentially, stained with cytochrome oxidase, and PMBSF measured. The sizes of barrels and the interbarrel septal region within PMBSF, as well as body and brain weights were compared between the three groups. The sizes of PMSBF barrel and septal areas were significantly smaller (P<.01) in Alc group compared to controls, while the PMBSF barrel pattern remained unaltered. Body, whole-brain, forebrain, and hemisphere weights were significantly reduced (P<.01) in Alc pups compared to control groups. GC and SC groups did not differ significantly in all dependent variables, except body weight at P9 and P10 (P<.01). These results suggest that postnatal alcohol exposure, like prenatal exposure, significantly influenced the size of the barrel field, but not barrel field pattern formation, indicating that barrel field pattern formation consolidated prior to P4. These results are important for understanding sensorimotor deficits reported in children suffering from fetal alcohol spectrum disorder (FASD).
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Affiliation(s)
- Akinniran Oladehin
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Memphis, TN 38163, USA
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Margret CP, Chappell TD, Li CX, Jan TA, Matta SG, Elberger AJ, Waters RS. Prenatal alcohol exposure (PAE) reduces the size of the forepaw representation in forepaw barrel subfield (FBS) cortex in neonatal rats: relationship between periphery and central representation. Exp Brain Res 2006; 172:387-96. [PMID: 16424976 DOI: 10.1007/s00221-005-0339-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Accepted: 12/12/2005] [Indexed: 10/25/2022]
Abstract
Prenatal alcohol exposure (PAE) alters limb development that may lead to structural and functional abnormalities of the limb reported in children diagnosed with Fetal Alcohol Spectrum Disorder. To determine whether PAE alters the central representation of the forelimb we used the rodent barrel cortex as our model system where it was possible to visualize and quantitatively measure the size of the forepaw representation in the forepaw barrel subfield (FBS) in first somatosensory cortex. In the present study, we examined the effects of PAE on pattern and size of the forepaw and forepaw representation in FBS in neonatal rats at gestational day 32 that corresponds to postnatal day 9. Pregnant Sprague-Dawley rats were chronically intubated with binge doses of ethanol (6 g/kg) from gestational day 1 through gestational day 20. The offspring of the ethanol treated dams comprised the ethanol (EtOH) group. The effect of PAE on the EtOH group was compared with a nutritional-controlled pairfed (PF) group and a normal chowfed (CF) group. The ventral (glabrous) surface area of the forepaw digits, length of digit 2 through digit 5, and the corresponding glabrous forepaw digit representations in the FBS were measured and compared between treatment groups. In rats exposed to in utero alcohol, the sizes of the overall glabrous forepaw and forepaw digits were significantly reduced in EtOH pups compared to CF and PF pups; overall glabrous forepaw area was 11% smaller than CF controls. Glabrous digit lengths were also smaller in EtOH rats compared to CF controls and significantly smaller in digit 2 through digit 4. The glabrous digit representation in FBS was 18% smaller in the EtOH group when compared to the CF treatment. However, PAE did not produce malformations in the forepaw or alter the pattern of the forepaw representation in FBS; instead, PAE significantly reduced both body and brain weights compared to controls. Unexpectedly, little or no correlation was observed between the size of the glabrous forepaw compared to the size of the glabrous forepaw representation in the FBS for any of the treatment groups. The present findings of PAE-related alterations in sensory periphery and the central cortical representation may underlie deficits in sensorimotor integration reported among children with Fetal Alcohol Spectrum Disorder.
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Affiliation(s)
- Cecilia P Margret
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Memphis, TN 38163, USA
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