1
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Buswinka CJ, Osgood RT, Simikyan RG, Rosenberg DB, Indzhykulian AA. The hair cell analysis toolbox is a precise and fully automated pipeline for whole cochlea hair cell quantification. PLoS Biol 2023; 21:e3002041. [PMID: 36947567 PMCID: PMC10069775 DOI: 10.1371/journal.pbio.3002041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 04/03/2023] [Accepted: 02/17/2023] [Indexed: 03/23/2023] Open
Abstract
Our sense of hearing is mediated by sensory hair cells, precisely arranged and highly specialized cells subdivided into outer hair cells (OHCs) and inner hair cells (IHCs). Light microscopy tools allow for imaging of auditory hair cells along the full length of the cochlea, often yielding more data than feasible to manually analyze. Currently, there are no widely applicable tools for fast, unsupervised, unbiased, and comprehensive image analysis of auditory hair cells that work well either with imaging datasets containing an entire cochlea or smaller sampled regions. Here, we present a highly accurate machine learning-based hair cell analysis toolbox (HCAT) for the comprehensive analysis of whole cochleae (or smaller regions of interest) across light microscopy imaging modalities and species. The HCAT is a software that automates common image analysis tasks such as counting hair cells, classifying them by subtype (IHCs versus OHCs), determining their best frequency based on their location along the cochlea, and generating cochleograms. These automated tools remove a considerable barrier in cochlear image analysis, allowing for faster, unbiased, and more comprehensive data analysis practices. Furthermore, HCAT can serve as a template for deep learning-based detection tasks in other types of biological tissue: With some training data, HCAT's core codebase can be trained to develop a custom deep learning detection model for any object on an image.
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Affiliation(s)
- Christopher J Buswinka
- Mass Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States of America
- Speech and Hearing Bioscience and Technology Program, Harvard University, Cambridge, Massachusetts, United States of America
| | - Richard T Osgood
- Mass Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Rubina G Simikyan
- Mass Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States of America
| | - David B Rosenberg
- Mass Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Artur A Indzhykulian
- Mass Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States of America
- Speech and Hearing Bioscience and Technology Program, Harvard University, Cambridge, Massachusetts, United States of America
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2
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Ackerman JE, Best KT, Muscat SN, Pritchett EM, Nichols AE, Wu CL, Loiselle AE. Defining the spatial-molecular map of fibrotic tendon healing and the drivers of Scleraxis-lineage cell fate and function. Cell Rep 2022; 41:111706. [PMID: 36417854 PMCID: PMC9741867 DOI: 10.1016/j.celrep.2022.111706] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 09/16/2022] [Accepted: 11/01/2022] [Indexed: 11/23/2022] Open
Abstract
Tendon injuries heal via a scar-mediated response, and there are no biological approaches to promote more regenerative healing. Mouse flexor tendons heal through the formation of spatially distinct tissue areas: a highly aligned tissue bridge between the native tendon stubs that is enriched for adult Scleraxis-lineage cells and a disorganized outer shell associated with peri-tendinous scar formation. However, the specific molecular programs that underpin these spatially distinct tissue profiles are poorly defined. In the present study, we combine lineage tracing of adult Scleraxis-lineage cells with spatial transcriptomic profiling to define the overarching molecular programs that govern tendon healing and cell-fate decisions. Pseudotime analysis identified three fibroblast trajectories (synthetic, fibrotic, and reactive) and key transcription factors regulating these fate-switching decisions, including the progression of adult Scleraxis-lineage cells through the reactive trajectory. Collectively, this resource defines the molecular mechanisms that coordinate the temporo-spatial healing phenotype, which can be leveraged to inform therapeutic candidate selection.
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Affiliation(s)
- Jessica E. Ackerman
- Center for Musculoskeletal Research, Department of Orthopedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14642, USA,Department of Pathology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA
| | - Katherine T. Best
- Center for Musculoskeletal Research, Department of Orthopedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14642, USA,Department of Pathology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA
| | - Samantha N. Muscat
- Center for Musculoskeletal Research, Department of Orthopedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14642, USA,Department of Pathology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA
| | - Elizabeth M. Pritchett
- Genomics Research Center, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA
| | - Anne E.C. Nichols
- Center for Musculoskeletal Research, Department of Orthopedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Chia-Lung Wu
- Center for Musculoskeletal Research, Department of Orthopedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14642, USA,Senior author
| | - Alayna E. Loiselle
- Center for Musculoskeletal Research, Department of Orthopedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14642, USA,Department of Pathology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA,Senior author,Lead contact,Correspondence:
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3
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Fan C, Zhao Y, Chen Y, Qin T, Lin J, Han S, Yan R, Lei T, Xie Y, Wang T, Gu S, Ouyang H, Shen W, Yin Z, Chen X. A Cd9 +Cd271 + stem/progenitor population and the SHP2 pathway contribute to neonatal-to-adult switching that regulates tendon maturation. Cell Rep 2022; 39:110762. [PMID: 35476985 DOI: 10.1016/j.celrep.2022.110762] [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: 12/18/2020] [Revised: 02/06/2022] [Accepted: 04/08/2022] [Indexed: 11/03/2022] Open
Abstract
Tendon maturation lays the foundation for postnatal tendon development, its proper mechanical function, and regeneration, but the critical cell populations and the entangled mechanisms remain poorly understood. Here, by integrating the structural, mechanical, and molecular properties, we show that post-natal days 7-14 are the crucial transitional stage for mouse tendon maturation. We decode the cellular and molecular regulatory networks at the single-cell level. We find that a nerve growth factor (NGF)-secreting Cd9+Cd271+ tendon stem/progenitor cell population mainly prompts conversion from neonate to adult tendon. Through single-cell gene regulatory network analysis, in vitro inhibitor identification, and in vivo tendon-specific Shp2 deletion, we find that SHP2 signaling is a regulator for tendon maturation. Our research comprehensively reveals the dynamic cell population transition during tendon maturation, implementing insights into the critical roles of the maturation-related stem cell population and SHP2 signaling pathway during tendon differentiation and regeneration.
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Affiliation(s)
- Chunmei Fan
- Dr. Li Dak Sum-Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China; Department of Sports Medicine, Zhejiang University School of Medicine, Hangzhou, China; China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, China
| | - Yanyan Zhao
- Dr. Li Dak Sum-Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China; Department of Sports Medicine, Zhejiang University School of Medicine, Hangzhou, China; China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, China
| | - Yangwu Chen
- Dr. Li Dak Sum-Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China; Department of Sports Medicine, Zhejiang University School of Medicine, Hangzhou, China; China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, China
| | - Tian Qin
- Dr. Li Dak Sum-Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China; Department of Sports Medicine, Zhejiang University School of Medicine, Hangzhou, China; China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, China
| | - Junxin Lin
- Dr. Li Dak Sum-Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China; Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Hangzhou, China; Department of Sports Medicine, Zhejiang University School of Medicine, Hangzhou, China; China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, China
| | - Shan Han
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong SAR, China
| | - Ruojin Yan
- Dr. Li Dak Sum-Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China; Department of Sports Medicine, Zhejiang University School of Medicine, Hangzhou, China; China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, China
| | - Tingyun Lei
- Dr. Li Dak Sum-Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China; Department of Sports Medicine, Zhejiang University School of Medicine, Hangzhou, China; China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, China
| | - Yuanhao Xie
- Dr. Li Dak Sum-Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China; Department of Sports Medicine, Zhejiang University School of Medicine, Hangzhou, China; China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, China
| | - Tingzhang Wang
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Shen Gu
- School of Biomedical Sciences, Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Hongwei Ouyang
- Dr. Li Dak Sum-Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China; Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Hangzhou, China; Department of Sports Medicine, Zhejiang University School of Medicine, Hangzhou, China; China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, China
| | - Weiliang Shen
- Dr. Li Dak Sum-Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, China.
| | - Zi Yin
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of Sir Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China; Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Hangzhou, China; Department of Sports Medicine, Zhejiang University School of Medicine, Hangzhou, China; China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, China.
| | - Xiao Chen
- Dr. Li Dak Sum-Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China; Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Hangzhou, China; Department of Sports Medicine, Zhejiang University School of Medicine, Hangzhou, China; China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, China.
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4
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Rigueur D, Roberts RR, Bobzin L, Merrill AE. A requirement for Fgfr2 in middle ear development. Genesis 2018; 57:e23252. [PMID: 30253032 DOI: 10.1002/dvg.23252] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 09/17/2018] [Accepted: 09/18/2018] [Indexed: 12/12/2022]
Abstract
The skeletal structure of the mammalian middle ear, which is composed of three endochondral ossicles suspended within a membranous air-filled capsule, plays a critical role in conducting sound. Gene mutations that alter skeletal development in the middle ear result in auditory impairment. Mutations in fibroblast growth factor receptor 2 (FGFR2), an important regulator of endochondral and intramembranous bone formation, cause a spectrum of congenital skeletal disorders featuring conductive hearing loss. Although the middle ear malformations in multiple FGFR2 gain-of-function disorders are clinically characterized, those in the FGFR2 loss-of-function disorder lacrimo-auriculo-dento-digital (LADD) syndrome are relatively undescribed. To better understand conductive hearing loss in LADD, we examined the middle ear skeleton of mice with conditional loss of Fgfr2. We find that decreased auditory function in Fgfr2 mutant mice correlates with hypoplasia of the auditory bulla and ectopic bone growth at sites of tendon/ligament attachment. We show that ectopic bone associated with the intra-articular ligaments of the incudomalleal joint is derived from Scx-expressing cells and preceded by decreased expression of the joint progenitor marker Gdf5. Together, these results identify a role for Fgfr2 in development of the middle ear skeletal tissues and suggest potential causes for conductive hearing loss in LADD syndrome.
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Affiliation(s)
- Diana Rigueur
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, California.,Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Ryan R Roberts
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, California.,Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Lauren Bobzin
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, California.,Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Amy E Merrill
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, California.,Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
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5
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Delgado Caceres M, Pfeifer CG, Docheva D. Understanding Tendons: Lessons from Transgenic Mouse Models. Stem Cells Dev 2018; 27:1161-1174. [PMID: 29978741 PMCID: PMC6121181 DOI: 10.1089/scd.2018.0121] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 07/05/2018] [Indexed: 12/26/2022] Open
Abstract
Tendons and ligaments are connective tissues that have been comparatively less studied than muscle and cartilage/bone, even though they are crucial for proper function of the musculoskeletal system. In tendon biology, considerable progress has been made in identifying tendon-specific genes (Scleraxis, Mohawk, and Tenomodulin) in the past decade. However, besides tendon function and the knowledge of a small number of important players in tendon biology, neither the ontogeny of the tenogenic lineage nor signaling cascades have been fully understood. This results in major drawbacks in treatment and repair options following tendon degeneration. In this review, we have systematically evaluated publications describing tendon-related genes, which were studied in depth and characterized by using knockout technologies and the subsequently generated transgenic mouse models (Tg) (knockout mice, KO). We report in a tabular manner, that from a total of 24 tendon-related genes, in 22 of the respective knockout mouse models, phenotypic changes were detected. Additionally, in some of the models it was described at which developmental stages these changes appeared and progressed. To summarize, only loss of Scleraxis and TGFβ signaling led to severe tendon developmental phenotypes, while mice deficient for various proteoglycans, Mohawk, EGR1 and 2, and Tenomodulin presented mild phenotypes. These data suggest that the tendon developmental system is well organized, orchestrated, and backed up; this is even more evident among the members of the proteoglycan family, where the compensatory effects are much clearer. In future, it will be of great importance to discover additional master tendon transcription factors and the genes that play crucial roles in tendon development. This would improve our understanding of the genetic makeup of tendons, and will increase the chances of generating tendon-specific drugs to advance overall treatment strategies.
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Affiliation(s)
- Manuel Delgado Caceres
- Experimental Trauma Surgery, Department of Trauma Surgery, University Regensburg Medical Centre, Regensburg, Germany
| | - Christian G. Pfeifer
- Experimental Trauma Surgery, Department of Trauma Surgery, University Regensburg Medical Centre, Regensburg, Germany
- Department of Trauma Surgery, University Regensburg Medical Centre, Regensburg, Germany
| | - Denitsa Docheva
- Experimental Trauma Surgery, Department of Trauma Surgery, University Regensburg Medical Centre, Regensburg, Germany
- Department of Medical Biology, Medical University-Plovdiv, Plovdiv, Bulgaria
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6
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Schomann T, Mezzanotte L, De Groot JCMJ, Rivolta MN, Hendriks SH, Frijns JHM, Huisman MA. Neuronal differentiation of hair-follicle-bulge-derived stem cells co-cultured with mouse cochlear modiolus explants. PLoS One 2017; 12:e0187183. [PMID: 29084289 PMCID: PMC5662184 DOI: 10.1371/journal.pone.0187183] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 10/16/2017] [Indexed: 11/18/2022] Open
Abstract
Stem-cell-based repair of auditory neurons may represent an attractive therapeutic option to restore sensorineural hearing loss. Hair-follicle-bulge-derived stem cells (HFBSCs) are promising candidates for this type of therapy, because they (1) have migratory properties, enabling migration after transplantation, (2) can differentiate into sensory neurons and glial cells, and (3) can easily be harvested in relatively high numbers. However, HFBSCs have never been used for this purpose. We hypothesized that HFBSCs can be used for cell-based repair of the auditory nerve and we have examined their migration and incorporation into cochlear modiolus explants and their subsequent differentiation. Modiolus explants obtained from adult wild-type mice were cultured in the presence of EF1α-copGFP-transduced HFBSCs, constitutively expressing copepod green fluorescent protein (copGFP). Also, modiolus explants without hair cells were co-cultured with DCX-copGFP-transduced HFBSCs, which demonstrate copGFP upon doublecortin expression during neuronal differentiation. Velocity of HFBSC migration towards modiolus explants was calculated, and after two weeks, co-cultures were fixed and processed for immunohistochemical staining. EF1α-copGFP HFBSC migration velocity was fast: 80.5 ± 6.1 μm/h. After arrival in the explant, the cells formed a fascicular pattern and changed their phenotype into an ATOH1-positive neuronal cell type. DCX-copGFP HFBSCs became green-fluorescent after integration into the explants, confirming neuronal differentiation of the cells. These results show that HFBSC-derived neuronal progenitors are migratory and can integrate into cochlear modiolus explants, while adapting their phenotype depending on this micro-environment. Thus, HFBSCs show potential to be employed in cell-based therapies for auditory nerve repair.
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Affiliation(s)
- Timo Schomann
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, Leiden, South Holland, the Netherlands
| | - Laura Mezzanotte
- Optical Molecular Imaging Group, Department of Radiology, Erasmus Medical Center, Rotterdam, South Holland, the Netherlands
| | - John C. M. J. De Groot
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, Leiden, South Holland, the Netherlands
| | - Marcelo N. Rivolta
- Centre for Stem Cell Biology, Department of Biomedical Science, University of Sheffield, Sheffield, England, United Kingdom
| | - Sanne H. Hendriks
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, Leiden, South Holland, the Netherlands
| | - Johan H. M. Frijns
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, Leiden, South Holland, the Netherlands
| | - Margriet A. Huisman
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, Leiden, South Holland, the Netherlands
- * E-mail:
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7
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Sakamoto A, Kuroda Y, Kanzaki S, Matsuo K. Dissection of the Auditory Bulla in Postnatal Mice: Isolation of the Middle Ear Bones and Histological Analysis. J Vis Exp 2017. [PMID: 28117786 PMCID: PMC5408703 DOI: 10.3791/55054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In most mammals, auditory ossicles in the middle ear, including the malleus, incus and stapes, are the smallest bones. In mice, a bony structure called the auditory bulla houses the ossicles, whereas the auditory capsule encloses the inner ear, namely the cochlea and semicircular canals. Murine ossicles are essential for hearing and thus of great interest to researchers in the field of otolaryngology, but their metabolism, development, and evolution are highly relevant to other fields. Altered bone metabolism can affect hearing function in adult mice, and various gene-deficient mice show changes in morphogenesis of auditory ossicles in utero. Although murine auditory ossicles are tiny, their manipulation is feasible if one understands their anatomical orientation and 3D structure. Here, we describe how to dissect the auditory bulla and capsule of postnatal mice and then isolate individual ossicles by removing part of the bulla. We also discuss how to embed the bulla and capsule in different orientations to generate paraffin or frozen sections suitable for preparation of longitudinal, horizontal, or frontal sections of the malleus. Finally, we enumerate anatomical differences between mouse and human auditory ossicles. These methods would be useful in analyzing pathological, developmental and evolutionary aspects of auditory ossicles and the middle ear in mice.
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Affiliation(s)
- Ayako Sakamoto
- Laboratory of Cell and Tissue Biology, Keio University School of Medicine
| | - Yukiko Kuroda
- Laboratory of Cell and Tissue Biology, Keio University School of Medicine
| | - Sho Kanzaki
- Department of Otolaryngology Head and Neck Surgery, Keio University School of Medicine
| | - Koichi Matsuo
- Laboratory of Cell and Tissue Biology, Keio University School of Medicine;
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8
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Bagchi RA, Lin J, Wang R, Czubryt MP. Regulation of fibronectin gene expression in cardiac fibroblasts by scleraxis. Cell Tissue Res 2016; 366:381-391. [PMID: 27324126 DOI: 10.1007/s00441-016-2439-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 05/24/2016] [Indexed: 10/21/2022]
Abstract
The glycoprotein fibronectin is a key component of the extracellular matrix. By interacting with numerous matrix and cell surface proteins, fibronectin plays important roles in cell adhesion, migration and intracellular signaling. Up-regulation of fibronectin occurs in tissue fibrosis, and previous studies have identified the pro-fibrotic factor TGFβ as an inducer of fibronectin expression, although the mechanism responsible remains unknown. We have previously shown that a key downstream effector of TGFβ signaling in cardiac fibroblasts is the transcription factor scleraxis, which in turn regulates the expression of a wide variety of extracellular matrix genes. We noted that fibronectin expression tracked closely with scleraxis expression, but it was unclear whether scleraxis directly regulated the fibronectin gene. Here, we report that scleraxis acts via two E-box binding sites in the proximal human fibronectin promoter to govern fibronectin expression, with the second E-box being both sufficient and necessary for scleraxis-mediated fibronectin expression to occur. A combination of electrophoretic mobility shift and chromatin immunoprecipitation assays indicated that scleraxis interacted to a greater degree with the second E-box. Over-expression or knockdown of scleraxis resulted in increased or decreased fibronectin expression, respectively, and scleraxis null mice presented with dramatically decreased immunolabeling for fibronectin in cardiac tissue sections compared to wild-type controls. Furthermore, scleraxis was required for TGFβ-induced fibronectin expression: TGFβ lost its ability to induce fibronectin expression following scleraxis knockdown. Together, these results demonstrate a novel and required role for scleraxis in the regulation of cardiac fibroblast fibronectin gene expression basally or in response to TGFβ.
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Affiliation(s)
- Rushita A Bagchi
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB, R2H 2A6, Canada.,Department of Physiology and Pathophysiology, College of Medicine, University of Manitoba, Winnipeg, MB, Canada.,Division of Cardiology, School of Medicine, University of Colorado Denver, Anschutz Medical Campus, RC2- Room 8450, Aurora, CO, 80045, USA
| | - Justin Lin
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB, R2H 2A6, Canada
| | - Ryan Wang
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB, R2H 2A6, Canada
| | - Michael P Czubryt
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB, R2H 2A6, Canada. .,Department of Physiology and Pathophysiology, College of Medicine, University of Manitoba, Winnipeg, MB, Canada.
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9
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Abstract
The mammalian ear is a complex structure divided into three main parts: the outer; middle; and inner ear. These parts are formed from all three germ layers and neural crest cells, which have to integrate successfully in order to form a fully functioning organ of hearing. Any defect in development of the outer and middle ear leads to conductive hearing loss, while defects in the inner ear can lead to sensorineural hearing loss. This review focuses on the development of the parts of the ear involved with sound transduction into the inner ear, and the parts largely ignored in the world of hearing research: the outer and middle ear. The published data on the embryonic origin, signalling, genetic control, development and timing of the mammalian middle and outer ear are reviewed here along with new data showing the Eustachian tube cartilage is of dual embryonic origin. The embryonic origin of some of these structures has only recently been uncovered (Science, 339, 2013, 1453; Development, 140, 2013, 4386), while the molecular mechanisms controlling the growth, structure and integration of many outer and middle ear components are hardly known. The genetic analysis of outer and middle ear development is rather limited, with a small number of genes often affecting either more than one part of the ear or having only very small effects on development. This review therefore highlights the necessity for further research into the development of outer and middle ear structures, which will be important for the understanding and treatment of conductive hearing loss.
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Affiliation(s)
- Neal Anthwal
- Craniofacial Development and Stem Cell BiologyKing's College LondonLondonUK
| | - Hannah Thompson
- Craniofacial Development and Stem Cell BiologyKing's College LondonLondonUK
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10
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Czubryt MP. A tale of 2 tissues: the overlapping role of scleraxis in tendons and the heart. Can J Physiol Pharmacol 2014; 92:707-12. [PMID: 25083735 DOI: 10.1139/cjpp-2013-0489] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Tissue integrity in the face of external physical forces requires the production of a strong extracellular matrix (ECM) composed primarily of the protein collagen. Tendons and the heart both withstand large and changing physical forces, and emerging evidence suggests that the transcription factor scleraxis plays a central role in responding to these forces by directly regulating the production of ECM components and (or) by determining the fate of matrix-producing cell types. Thus, despite the highly disparate inherent nature of these tissues, a common response mechanism may exist to govern the development, growth, and remodeling of the ECM in response to external force.
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Affiliation(s)
- Michael P Czubryt
- R4008 St. Boniface Research Centre, 351 Tache Avenue, University of Manitoba, Winnipeg, MB R2H 2A6, Canada
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11
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Mann ZF, Chang W, Lee KY, King KA, Kelley MW. Expression and function of scleraxis in the developing auditory system. PLoS One 2013; 8:e75521. [PMID: 24058692 PMCID: PMC3772897 DOI: 10.1371/journal.pone.0075521] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 08/16/2013] [Indexed: 01/02/2023] Open
Abstract
A study of genes expressed in the developing inner ear identified the bHLH transcription factor Scleraxis (Scx) in the developing cochlea. Previous work has demonstrated an essential role for Scx in the differentiation and development of tendons, ligaments and cells of chondrogenic lineage. Expression in the cochlea has been shown previously, however the functional role for Scx in the cochlea is unknown. Using a Scx-GFP reporter mouse line we examined the spatial and temporal patterns of Scx expression in the developing cochlea between embryonic day 13.5 and postnatal day 25. Embryonically, Scx is expressed broadly throughout the cochlear duct and surrounding mesenchyme and at postnatal ages becomes restricted to the inner hair cells and the interdental cells of the spiral limbus. Deletion of Scx results in hearing impairment indicated by elevated auditory brainstem response (ABR) thresholds and diminished distortion product otoacoustic emission (DPOAE) amplitudes, across a range of frequencies. No changes in either gross cochlear morphology or expression of the Scx target genes Col2A, Bmp4 or Sox9 were observed in Scx(-/-) mutants, suggesting that the auditory defects observed in these animals may be a result of unidentified Scx-dependent processes within the cochlea.
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Affiliation(s)
- Zoe F. Mann
- Laboratory of Cochlear Development, NIDCD, NIH, Bethesda, Maryland, United States of America
- * E-mail:
| | - Weise Chang
- Laboratory of Cochlear Development, NIDCD, NIH, Bethesda, Maryland, United States of America
| | - Kyu Yup Lee
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, NIH, Rockville, Maryland, United States of America
| | - Kelly A. King
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, United States of America
| | - Matthew W. Kelley
- Laboratory of Cochlear Development, NIDCD, NIH, Bethesda, Maryland, United States of America
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Bhandari RK, Schinke EN, Haque MM, Sadler-Riggleman I, Skinner MK. SRY induced TCF21 genome-wide targets and cascade of bHLH factors during Sertoli cell differentiation and male sex determination in rats. Biol Reprod 2012; 87:131. [PMID: 23034159 DOI: 10.1095/biolreprod.112.099663] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Male sex determination is initiated through the testis-determining factor SRY that promotes Sertoli cell differentiation and subsequent gonadal development. The basic helix-loop-helix (bHLH) gene Tcf21 was identified as one of the direct downstream targets of SRY. The current study was designed to identify the downstream targets of TCF21 and the potential cascade of bHLH genes that promote Sertoli cell differentiation. A modified ChIP-Chip comparative hybridization analysis identified 121 direct downstream binding targets for TCF21. The gene networks and cellular pathways potentially regulated by these TCF21 targets were identified. One of the main bHLH targets for TCF21 was the bHLH gene scleraxis (Scx). An embryonic ovarian gonadal cell culture was used to examine the functional role of Sry, Tcf21, and Scx to promote an in vitro sex reversal and induction of Sertoli cell differentiation. SRY and TCF21 were found to induce the initial stages of Sertoli cell differentiation, whereas SCX was found to induce the later stages of Sertoli cell differentiation associated with pubertal development using transferrin gene expression as a marker. Therefore, a cascade of SRY followed by TCF21 followed by SCX appears to promote, in part, Sertoli cell fate determination and subsequent differentiation. The current observations help elucidate the initial molecular events involved in the induction of Sertoli cell differentiation and testis development.
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Affiliation(s)
- Ramji K Bhandari
- Center for Reproductive Biology, School of Biological Sciences, Washington State University, Pullman, Washington, USA
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Hilton JM, Lewis MA, Grati M, Ingham N, Pearson S, Laskowski RA, Adams DJ, Steel KP. Exome sequencing identifies a missense mutation in Isl1 associated with low penetrance otitis media in dearisch mice. Genome Biol 2011; 12:R90. [PMID: 21936904 PMCID: PMC3308053 DOI: 10.1186/gb-2011-12-9-r90] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 08/02/2011] [Accepted: 09/21/2011] [Indexed: 02/06/2023] Open
Abstract
Background Inflammation of the middle ear (otitis media) is very common and can lead to serious complications if not resolved. Genetic studies suggest an inherited component, but few of the genes that contribute to this condition are known. Mouse mutants have contributed significantly to the identification of genes predisposing to otitis media Results The dearisch mouse mutant is an ENU-induced mutant detected by its impaired Preyer reflex (ear flick in response to sound). Auditory brainstem responses revealed raised thresholds from as early as three weeks old. Pedigree analysis suggested a dominant but partially penetrant mode of inheritance. The middle ear of dearisch mutants shows a thickened mucosa and cellular effusion suggesting chronic otitis media with effusion with superimposed acute infection. The inner ear, including the sensory hair cells, appears normal. Due to the low penetrance of the phenotype, normal backcross mapping of the mutation was not possible. Exome sequencing was therefore employed to identify a non-conservative tyrosine to cysteine (Y71C) missense mutation in the Islet1 gene, Isl1Drsh. Isl1 is expressed in the normal middle ear mucosa. The findings suggest the Isl1Drshmutation is likely to predispose carriers to otitis media. Conclusions Dearisch, Isl1Drsh, represents the first point mutation in the mouse Isl1 gene and suggests a previously unrecognized role for this gene. It is also the first recorded exome sequencing of the C3HeB/FeJ background relevant to many ENU-induced mutants. Most importantly, the power of exome resequencing to identify ENU-induced mutations without a mapped gene locus is illustrated.
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