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Tsukada K, Nishio SY, Takumi Y, Usami SI. Comparison of vestibular function in hereditary hearing loss patients with GJB2, CDH23, and SLC26A4 variants. Sci Rep 2024; 14:10596. [PMID: 38720048 PMCID: PMC11078969 DOI: 10.1038/s41598-024-61442-3] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 05/06/2024] [Indexed: 05/12/2024] Open
Abstract
To investigate the association between hereditary hearing loss and vestibular function, we compared vestibular function and symptoms among patients with GJB2, SLC26A4, and CDH23 variants. Thirty-nine patients with sensory neural hearing loss (11 males and 28 females) with biallelic pathogenic variants in either GJB2, SLC26A4, or CDH23 were included in this study (13 GJB2, 15 SLC26A4, and 11 CDH23). The patients were examined using caloric testing and cervical and ocular vestibular-evoked myogenic potentials (cVEMP and oVEMP). We also compared vestibular function and symptoms between patients with these gene variants and 78 normal-hearing ears without vestibular symptoms as controls. The frequency of semicircular canal hypofunction in caloric testing was higher in patients with SLC26A4 variants (47%) than in those with GJB2 (0%) and CDH23 variants (27%). According to the cVEMP results, 69% of patients with GJB2 variants had saccular hypofunction, a significantly higher proportion than in those carrying other variants (SLC26A4, 20%; CDH23, 18%). In oVEMP, which reflects utricular function, no difference was observed in the frequency of hypofunction among the three genes (GJB2, 15%; SLC26A4, 40%; and CDH23, 36%). Hence, discernable trends indicate vestibular dysfunction associated with each gene.
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Affiliation(s)
- Keita Tsukada
- Department of Otorhinolaryngology Head and Neck Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
| | - Shin-Ya Nishio
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan
| | - Yutaka Takumi
- Department of Otorhinolaryngology Head and Neck Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan
| | - Shin-Ichi Usami
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan
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2
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Ito T, Watanabe H, Honda K, Fujikawa T, Kitamura K, Tsutsumi T. The role of SLC26A4 in bony labyrinth development and otoconial mineralization in mouse models. Front Mol Neurosci 2024; 17:1384764. [PMID: 38742227 PMCID: PMC11089141 DOI: 10.3389/fnmol.2024.1384764] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 04/15/2024] [Indexed: 05/16/2024] Open
Abstract
Inner ear malformations are predominantly attributed to developmental arrest during the embryonic stage of membranous labyrinth development. Due to the inherent difficulty in clinically assessing the status of the membranous labyrinth, these malformations are diagnosed with radiographic imaging, based on the morphological characteristics of the bony labyrinth. While extensive research has elucidated the intricacies of membranous labyrinth development in mouse models, comprehensive investigations into the developmental trajectory of the bony labyrinth, especially about its calcification process, have been notably lacking. One of the most prominent types of inner ear malformations is known as incomplete partition (IP), characterized by nearly normal external cochlear appearance but pronounced irregularities in the morphology of the modiolus and inter-scalar septa. IP type II (IP-II), also known as Mondini dysplasia, is generally accompanied by an enlargement of the vestibular aqueduct and is primarily attributed to mutations in the SLC26A4 gene. In the case of IP-II, the modiolus and inter-scalar septa of the cochlear apex are underdeveloped or missing, resulting in the manifestation of a cystic structure on radiographic imaging. In this overview, we not only explore the normal development of the bony labyrinth in mice but also present our observations on otolith mineralization. Furthermore, we investigated the specifics of bony labyrinth and otolith mineralization in Slc26a4-deficient mice, which served as an animal model for IP-II. We ensured that these findings promise to provide valuable insights for the establishment of therapeutic interventions, optimal timing, targeted sites, and preventive measures when considering the management of this condition.
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Affiliation(s)
- Taku Ito
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hiroki Watanabe
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Keiji Honda
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Taro Fujikawa
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ken Kitamura
- Department of Otorhinolaryngology, Chigasaki Chuo Hospital, Kanagawa, Japan
| | - Takeshi Tsutsumi
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
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3
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Takahashi S, Homma K. The molecular principles underlying diverse functions of the SLC26 family of proteins. J Biol Chem 2024; 300:107261. [PMID: 38582450 PMCID: PMC11078650 DOI: 10.1016/j.jbc.2024.107261] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/07/2024] [Accepted: 03/30/2024] [Indexed: 04/08/2024] Open
Abstract
Mammalian SLC26 proteins are membrane-based anion transporters that belong to the large SLC26/SulP family, and many of their variants are associated with hereditary diseases. Recent structural studies revealed a strikingly similar homodimeric molecular architecture for several SLC26 members, implying a shared molecular principle. Now a new question emerges as to how these structurally similar proteins execute diverse physiological functions. In this study, we sought to identify the common versus distinct molecular mechanism among the SLC26 proteins using both naturally occurring and artificial missense changes introduced to SLC26A4, SLC26A5, and SLC26A9. We found: (i) the basic residue at the anion binding site is essential for both anion antiport of SLC26A4 and motor functions of SLC26A5, and its conversion to a nonpolar residue is crucial but not sufficient for the fast uncoupled anion transport in SLC26A9; (ii) the conserved polar residues in the N- and C-terminal cytosolic domains are likely involved in dynamic hydrogen-bonding networks and are essential for anion antiport of SLC26A4 but not for motor (SLC26A5) and uncoupled anion transport (SLC26A9) functions; (iii) the hydrophobic interaction between each protomer's last transmembrane helices, TM14, is not of functional significance in SLC26A9 but crucial for the functions of SLC26A4 and SLC26A5, likely contributing to optimally orient the axis of the relative movements of the core domain with respect to the gate domains within the cell membrane. These findings advance our understanding of the molecular mechanisms underlying the diverse physiological roles of the SLC26 family of proteins.
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Affiliation(s)
- Satoe Takahashi
- Department of Otolaryngology - Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; Center for Mechanical Excitability, The University of Chicago, Chicago, Illinois, USA
| | - Kazuaki Homma
- Department of Otolaryngology - Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; Center for Mechanical Excitability, The University of Chicago, Chicago, Illinois, USA; The Hugh Knowles Center for Clinical and Basic Science in Hearing and Its Disorders, Northwestern University, Evanston, Illinois, USA.
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Takahashi S, Kojima T, Wasano K, Homma K. Functional Studies of Deafness-Associated Pendrin and Prestin Variants. Int J Mol Sci 2024; 25:2759. [PMID: 38474007 PMCID: PMC10931795 DOI: 10.3390/ijms25052759] [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: 01/30/2024] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 03/14/2024] Open
Abstract
Pendrin and prestin are evolutionary-conserved membrane proteins that are essential for normal hearing. Dysfunction of these proteins results in hearing loss in humans, and numerous deafness-associated pendrin and prestin variants have been identified in patients. However, the pathogenic impacts of many of these variants are ambiguous. Here, we report results from our ongoing efforts to experimentally characterize pendrin and prestin variants using in vitro functional assays. With previously established fluorometric anion transport assays, we determined that many of the pendrin variants identified on transmembrane (TM) 10, which contains the essential anion binding site, and on the neighboring TM9 within the core domain resulted in impaired anion transport activity. We also determined the range of functional impairment in three deafness-associated prestin variants by measuring nonlinear capacitance (NLC), a proxy for motor function. Using the results from our functional analyses, we also evaluated the performance of AlphaMissense (AM), a computational tool for predicting the pathogenicity of missense variants. AM prediction scores correlated well with our experimental results; however, some variants were misclassified, underscoring the necessity of experimentally assessing the effects of variants. Together, our experimental efforts provide invaluable information regarding the pathogenicity of deafness-associated pendrin and prestin variants.
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Affiliation(s)
- Satoe Takahashi
- Department of Otolaryngology—Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Takashi Kojima
- Department of Otolaryngology—Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Department of Otolaryngology, Head and Neck Surgery, National Hospital Organization Tochigi Medical Center, Tochigi 320-0057, Japan
| | - Koichiro Wasano
- Department of Otolaryngology—Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Department of Otolaryngology, Head and Neck Surgery, Tokai University School of Medicine, Isehara 259-1193, Japan
| | - Kazuaki Homma
- Department of Otolaryngology—Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- The Hugh Knowles Center for Clinical and Basic Science in Hearing and Its Disorders, Northwestern University, Evanston, IL 60208, USA
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Herb M. NADPH Oxidase 3: Beyond the Inner Ear. Antioxidants (Basel) 2024; 13:219. [PMID: 38397817 PMCID: PMC10886416 DOI: 10.3390/antiox13020219] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 02/02/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Reactive oxygen species (ROS) were formerly known as mere byproducts of metabolism with damaging effects on cellular structures. The discovery and description of NADPH oxidases (Nox) as a whole enzyme family that only produce this harmful group of molecules was surprising. After intensive research, seven Nox isoforms were discovered, described and extensively studied. Among them, the NADPH oxidase 3 is the perhaps most underrated Nox isoform, since it was firstly discovered in the inner ear. This stigma of Nox3 as "being only expressed in the inner ear" was also used by me several times. Therefore, the question arose whether this sentence is still valid or even usable. To this end, this review solely focuses on Nox3 and summarizes its discovery, the structural components, the activating and regulating factors, the expression in cells, tissues and organs, as well as the beneficial and detrimental effects of Nox3-mediated ROS production on body functions. Furthermore, the involvement of Nox3-derived ROS in diseases progression and, accordingly, as a potential target for disease treatment, will be discussed.
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Affiliation(s)
- Marc Herb
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine, University Hospital Cologne, University of Cologne, 50935 Cologne, Germany;
- German Centre for Infection Research, Partner Site Bonn-Cologne, 50931 Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Aging-Associated Diseases (CECAD), 50931 Cologne, Germany
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Takahashi S, Kojima T, Wasano K, Homma K. Functional studies of deafness-associated pendrin and prestin variants. bioRxiv 2024:2024.01.23.576877. [PMID: 38328051 PMCID: PMC10849616 DOI: 10.1101/2024.01.23.576877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Pendrin and prestin are evolutionary conserved membrane proteins that are essential for normal hearing. Pendrin is an anion transporter required for normal development and maintenance of ion homeostasis in the inner ear, while prestin is a voltage-dependent motor responsible for cochlear amplification essential for high sensitivity and frequency selectivity of mammalian hearing. Dysfunction of these proteins result in hearing loss in humans, and numerous deafness-associated pendrin and prestin variants have been identified in patients. However, the pathogenic impacts of many of these variants are ambiguous. Here we report results from our ongoing efforts in experimentally characterizing pendrin and prestin variants using in vitro functional assays, providing invaluable information regarding their pathogenicity.
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7
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Warren B, Eberl D. What can insects teach us about hearing loss? J Physiol 2024; 602:297-316. [PMID: 38128023 DOI: 10.1113/jp281281] [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: 05/26/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023] Open
Abstract
Over the last three decades, insects have been utilized to provide a deep and fundamental understanding of many human diseases and disorders. Here, we present arguments for insects as models to understand general principles underlying hearing loss. Despite ∼600 million years since the last common ancestor of vertebrates and invertebrates, we share an overwhelming degree of genetic homology particularly with respect to auditory organ development and maintenance. Despite the anatomical differences between human and insect auditory organs, both share physiological principles of operation. We explain why these observations are expected and highlight areas in hearing loss research in which insects can provide insight. We start by briefly introducing the evolutionary journey of auditory organs, the reasons for using insect auditory organs for hearing loss research, and the tools and approaches available in insects. Then, the first half of the review focuses on auditory development and auditory disorders with a genetic cause. The second half analyses the physiological and genetic consequences of ageing and short- and long-term changes as a result of noise exposure. We finish with complex age and noise interactions in auditory systems. In this review, we present some of the evidence and arguments to support the use of insects to study mechanisms and potential treatments for hearing loss in humans. Obviously, insects cannot fully substitute for all aspects of human auditory function and loss of function, although there are many important questions that can be addressed in an animal model for which there are important ethical, practical and experimental advantages.
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Affiliation(s)
- Ben Warren
- Neurogenetics Group, College of Life Sciences, University of Leicester, Leicester, UK
| | - Daniel Eberl
- Department of Biology, University of Iowa, Iowa City, IA, USA
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8
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Geertsma ER, Oliver D. SLC26 Anion Transporters. Handb Exp Pharmacol 2024; 283:319-360. [PMID: 37947907 DOI: 10.1007/164_2023_698] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Solute carrier family 26 (SLC26) is a family of functionally diverse anion transporters found in all kingdoms of life. Anions transported by SLC26 proteins include chloride, bicarbonate, and sulfate, but also small organic dicarboxylates such as fumarate and oxalate. The human genome encodes ten functional homologs, several of which are causally associated with severe human diseases, highlighting their physiological importance. Here, we review novel insights into the structure and function of SLC26 proteins and summarize the physiological relevance of human members.
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Affiliation(s)
- Eric R Geertsma
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
| | - Dominik Oliver
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University Marburg, Marburg, Germany.
- Center for Mind, Brain and Behavior (CMBB), Universities of Marburg and Giessen, Marburg, Giessen, Germany.
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9
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Takahashi S, Homma K. The molecular principles underlying diverse functions of the SLC26 family of proteins. bioRxiv 2023:2023.12.10.570988. [PMID: 38106153 PMCID: PMC10723444 DOI: 10.1101/2023.12.10.570988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Mammalian SLC26 proteins are membrane-based anion transporters that belong to the large SLC26/SulP family, and many of their variants are associated with hereditary diseases. Recent structural studies revealed a strikingly similar homodimeric molecular architecture for several SLC26 members, implying a shared molecular principle. Now a new question emerges as to how these structurally similar proteins execute diverse physiological functions. In this study we sought to identify the common vs. distinct molecular mechanism among the SLC26 proteins using both naturally occurring and artificial missense changes introduced to SLC26A4, SLC26A5, and SLC26A9. We found: (i) the basic residue at the anion binding site is essential for both anion antiport of SLC26A4 and motor functions of SLC26A5, and its conversion to a nonpolar residue is crucial but not sufficient for the fast uncoupled anion transport in SLC26A9; (ii) the conserved polar residues in the N- and C-terminal cytosolic domains are likely involved in dynamic hydrogen-bonding networks and are essential for anion antiport of SLC26A4 but not for motor (SLC26A5) and uncoupled anion transport (SLC26A9) functions; (iii) the hydrophobic interaction between each protomer's last transmembrane helices, TM14, is not of functional significance in SLC26A9 but crucial for the functions of SLC26A4 and SLC26A5, likely contributing to optimally orient the axis of the relative movements of the core domain with respect to the gate domains within the cell membrane. These findings advance our understanding of the molecular mechanisms underlying the diverse physiological roles of the SLC26 family of proteins.
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10
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Feng Y, Hu S, Zhao S, Chen M. Recent advances in genetic etiology of non-syndromic deafness in children. Front Neurosci 2023; 17:1282663. [PMID: 37928735 PMCID: PMC10620706 DOI: 10.3389/fnins.2023.1282663] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/04/2023] [Indexed: 11/07/2023] Open
Abstract
Congenital auditory impairment is a prevalent anomaly observed in approximately 2-3 per 1,000 infants. The consequences associated with hearing loss among children encompass the decline of verbal communication, linguistic skills, educational progress, social integration, cognitive aptitude, and overall well-being. Approaches to reversing or preventing genetic hearing loss are limited. Patients with mild and moderate hearing loss can only use hearing aids, while those with severe hearing loss can only acquire speech and language through cochlear implants. Both environmental and genetic factors contribute to the occurrence of congenital hearing loss, and advancements in our understanding of the pathophysiology and molecular mechanisms underlying hearing loss, coupled with recent progress in genetic testing techniques, will facilitate the development of innovative approaches for treatment and screening. In this paper, the latest research progress in genetic etiology of non-syndromic deafness in children with the highest incidence is summarized in order to provide help for personalized diagnosis and treatment of deafness in children.
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Al-Qusairi L, Ferdaus MZ, Pham TD, Li D, Grimm PR, Zapf AM, Abood DC, Tahaei E, Delpire E, Wall SM, Welling PA. Dietary anions control potassium excretion: it is more than a poorly absorbable anion effect. Am J Physiol Renal Physiol 2023; 325:F377-F393. [PMID: 37498547 PMCID: PMC10639028 DOI: 10.1152/ajprenal.00193.2023] [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: 07/11/2023] [Revised: 07/20/2023] [Accepted: 07/22/2023] [Indexed: 07/28/2023] Open
Abstract
The urinary potassium (K+) excretion machinery is upregulated with increasing dietary K+, but the role of accompanying dietary anions remains inadequately characterized. Poorly absorbable anions, including [Formula: see text], are thought to increase K+ secretion through a transepithelial voltage effect. Here, we tested if they also influence the K+ secretion machinery. Wild-type mice, aldosterone synthase (AS) knockout (KO) mice, or pendrin KO mice were randomized to control, high-KCl, or high-KHCO3 diets. The K+ secretory capacity was assessed in balance experiments. Protein abundance, modification, and localization of K+-secretory transporters were evaluated by Western blot analysis and confocal microscopy. Feeding the high-KHCO3 diet increased urinary K+ excretion and the transtubular K+ gradient significantly more than the high-KCl diet, coincident with more pronounced upregulation of epithelial Na+ channels (ENaC) and renal outer medullary K+ (ROMK) channels and apical localization in the distal nephron. Experiments in AS KO mice revealed that the enhanced effects of [Formula: see text] were aldosterone independent. The high-KHCO3 diet also uniquely increased the large-conductance Ca2+-activated K+ (BK) channel β4-subunit, stabilizing BKα on the apical membrane, the Cl-/[Formula: see text] exchanger, pendrin, and the apical KCl cotransporter (KCC3a), all of which are expressed specifically in pendrin-positive intercalated cells. Experiments in pendrin KO mice revealed that pendrin was required to increase K+ excretion with the high-KHCO3 diet. In summary, [Formula: see text] stimulates K+ excretion beyond a poorly absorbable anion effect, upregulating ENaC and ROMK in principal cells and BK, pendrin, and KCC3a in pendrin-positive intercalated cells. The adaptive mechanism prevents hyperkalemia and alkalosis with the consumption of alkaline ash-rich diets but may drive K+ wasting and hypokalemia in alkalosis.NEW & NOTEWORTHY Dietary anions profoundly impact K+ homeostasis. Here, we found that a K+-rich diet, containing [Formula: see text] as the counteranion, enhances the electrogenic K+ excretory machinery, epithelial Na+ channels, and renal outer medullary K+ channels, much more than a high-KCl diet. It also uniquely induces KCC3a and pendrin, in B-intercalated cells, providing an electroneutral KHCO3 secretion pathway. These findings reveal new K+ balance mechanisms that drive adaption to alkaline and K+-rich foods, which should guide new treatment strategies for K+ disorders.
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Affiliation(s)
- Lama Al-Qusairi
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
- Department of Nephrology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Mohammed Z Ferdaus
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Truyen D Pham
- Department of Medicine Nephrology, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Dimin Li
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
- Department of Nephrology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - P Richard Grimm
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
- Department of Nephrology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Ava M Zapf
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
- Department of Nephrology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Delaney C Abood
- Department of Medicine Nephrology, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Ebrahim Tahaei
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
- Department of Nephrology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Susan M Wall
- Department of Medicine Nephrology, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Paul A Welling
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
- Department of Nephrology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
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Bai J, Ito T, Fujikawa T, Honda K, Kawashima Y, Watanabe H, Kurata N, Tsutsumi T. Three-dimensionally visualized ossification and mineralization process of the otic capsule in a postnatal developmental mouse. Laryngoscope Investig Otolaryngol 2023; 8:1036-1043. [PMID: 37621296 PMCID: PMC10446274 DOI: 10.1002/lio2.1090] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 05/29/2023] [Indexed: 08/26/2023] Open
Abstract
Objective We aimed to elucidate the ossification process of the otic capsule in postnatal C57BL/6 mice and depict the three-dimensional (3D) process of otoconial mineralization in vivo. Methods The otic capsules of C57BL/6 mice were stained with alizarin red and imaged/compared using micro-computed tomography on postnatal day (P) between P0 and P8, P10, P15, and P30 and 3-4 months old (P3-4Mo). We reconstructed 3D images of the otic capsule and otoconia and measured the bone mineral density using x-ray absorptiometry on each age. Results The 3D reconstructed otic capsule images revealed two ossification centers of the otic capsule at P0. One was observed around the ampulla of the superior semicircular canal and utricle, and the other was observed around the ampulla of the posterior semicircular canal. The cross-sectional views demonstrated that modiolar ossification developed from the base to the apex from P4 to P8. The inter-scalar septum ossified bidirectionally from the modiolus and bony otic capsule from P8 to P15. The mineralized otoconia were first detected in the utricle at P3 and saccular otoconia at P6. The density of the utricle and saccular otoconia showed different growth trends. Conclusion To the best of our knowledge, this is the first study to demonstrate the 3D appearance of the otic capsule and otoconia in different developmental stages of mice. We also revealed that modiolar and inter-scalar septal calcification is the final event in the cochlea and that it can be susceptible to pathological conditions (cochlear congenital malformations and hereditary vestibular diseases). The unique features of the ossification process and duration may explain these pathological conditions observed in humans. Level of Evidence 3.
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Affiliation(s)
- Jing Bai
- Department of OtolaryngologyTokyo Medical and Dental UniversityTokyoJapan
| | - Taku Ito
- Department of OtolaryngologyTokyo Medical and Dental UniversityTokyoJapan
| | - Taro Fujikawa
- Department of OtolaryngologyTokyo Medical and Dental UniversityTokyoJapan
| | - Keiji Honda
- Department of OtolaryngologyTokyo Medical and Dental UniversityTokyoJapan
| | | | - Hiroki Watanabe
- Department of OtolaryngologyTokyo Medical and Dental UniversityTokyoJapan
| | - Natsuko Kurata
- Department of OtolaryngologyTokyo Medical and Dental UniversityTokyoJapan
| | - Takeshi Tsutsumi
- Department of OtolaryngologyTokyo Medical and Dental UniversityTokyoJapan
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13
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Berg P, Jensen T, Andersen JF, Svendsen SL, Modvig IM, Wang T, Frische S, Chow BKC, Malte H, Holst JJ, Sørensen MV, Leipziger J. Loss of the Secretin Receptor Impairs Renal Bicarbonate Excretion and Aggravates Metabolic Alkalosis in Mice during Acute Base-Loading. J Am Soc Nephrol 2023; 34:1329-1342. [PMID: 37344929 PMCID: PMC10400107 DOI: 10.1681/asn.0000000000000173] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 05/12/2023] [Indexed: 06/23/2023] Open
Abstract
SIGNIFICANCE STATEMENT During acute base excess, the renal collecting duct β -intercalated cells ( β -ICs) become activated to increase urine base excretion. This process is dependent on pendrin and cystic fibrosis transmembrane regulator (CFTR) expressed in the apical membrane of β -ICs. The signal that leads to activation of this process was unknown. Plasma secretin levels increase during acute alkalosis, and the secretin receptor (SCTR) is functionally expressed in β -ICs. We find that mice with global knockout for the SCTR lose their ability to acutely increase renal base excretion. This forces the mice to lower their ventilation to cope with this challenge. Our findings suggest that secretin is a systemic bicarbonate-regulating hormone, likely being released from the small intestine during alkalosis. BACKGROUND The secretin receptor (SCTR) is functionally expressed in the basolateral membrane of the β -intercalated cells of the kidney cortical collecting duct and stimulates urine alkalization by activating the β -intercalated cells. Interestingly, the plasma secretin level increases during acute metabolic alkalosis, but its role in systemic acid-base homeostasis was unclear. We hypothesized that the SCTR system is essential for renal base excretion during acute metabolic alkalosis. METHODS We conducted bladder catheterization experiments, metabolic cage studies, blood gas analysis, barometric respirometry, perfusion of isolated cortical collecting ducts, immunoblotting, and immunohistochemistry in SCTR wild-type and knockout (KO) mice. We also perfused isolated rat small intestines to study secretin release. RESULTS In wild-type mice, secretin acutely increased urine pH and pendrin function in isolated perfused cortical collecting ducts. These effects were absent in KO mice, which also did not sufficiently increase renal base excretion during acute base loading. In line with these findings, KO mice developed prolonged metabolic alkalosis when exposed to acute oral or intraperitoneal base loading. Furthermore, KO mice exhibited transient but marked hypoventilation after acute base loading. In rats, increased blood alkalinity of the perfused upper small intestine increased venous secretin release. CONCLUSIONS Our results suggest that loss of SCTR impairs the appropriate increase of renal base excretion during acute base loading and that SCTR is necessary for acute correction of metabolic alkalosis. In addition, our findings suggest that blood alkalinity increases secretin release from the small intestine and that secretin action is critical for bicarbonate homeostasis.
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Affiliation(s)
- Peder Berg
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Tobias Jensen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | | | - Ida Maria Modvig
- Department of Biomedical Sciences, Copenhagen University, Copenhagen, Denmark
| | - Tobias Wang
- Department of Biology, Zoophysiology, Aarhus University, Aarhus, Denmark
| | | | - Billy K. C. Chow
- School of Biological Sciences, The University of Hong Kong, Hong Kong
| | - Hans Malte
- Department of Biology, Zoophysiology, Aarhus University, Aarhus, Denmark
| | - Jens Juul Holst
- Department of Biomedical Sciences, Copenhagen University, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Copenhagen University, Copenhagen, Denmark
| | | | - Jens Leipziger
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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14
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Koh JY, Affortit C, Ranum PT, West C, Walls WD, Yoshimura H, Shao JQ, Mostaert B, Smith RJH. Single-cell RNA-sequencing of stria vascularis cells in the adult Slc26a4 -/- mouse. BMC Med Genomics 2023; 16:133. [PMID: 37322474 PMCID: PMC10268361 DOI: 10.1186/s12920-023-01549-0] [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: 01/20/2023] [Accepted: 05/15/2023] [Indexed: 06/17/2023] Open
Abstract
BACKGROUND The primary pathological alterations of Pendred syndrome are endolymphatic pH acidification and luminal enlargement of the inner ear. However, the molecular contributions of specific cell types remain poorly characterized. Therefore, we aimed to identify pH regulators in pendrin-expressing cells that may contribute to the homeostasis of endolymph pH and define the cellular pathogenic mechanisms that contribute to the dysregulation of cochlear endolymph pH in Slc26a4-/- mice. METHODS We used single-cell RNA sequencing to identify both Slc26a4-expressing cells and Kcnj10-expressing cells in wild-type (WT, Slc26a4+/+) and Slc26a4-/- mice. Bioinformatic analysis of expression data confirmed marker genes defining the different cell types of the stria vascularis. In addition, specific findings were confirmed at the protein level by immunofluorescence. RESULTS We found that spindle cells, which express pendrin, contain extrinsic cellular components, a factor that enables cell-to-cell communication. In addition, the gene expression profile informed the pH of the spindle cells. Compared to WT, the transcriptional profiles in Slc26a4-/- mice showed downregulation of extracellular exosome-related genes in spindle cells. Immunofluorescence studies in spindle cells of Slc26a4-/- mice validated the increased expression of the exosome-related protein, annexin A1, and the clathrin-mediated endocytosis-related protein, adaptor protein 2. CONCLUSION Overall, cell isolation of stria vascularis from WT and Slc26a4-/- samples combined with cell type-specific transcriptomic analyses revealed pH-dependent alternations in spindle cells and intermediate cells, inspiring further studies into the dysfunctional role of stria vascularis cells in SLC26A4-related hearing loss.
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Affiliation(s)
- Jin-Young Koh
- Roy J. Carver Department of Biomedical Engineering, College of Engineering, University of Iowa, University of Iowa, Iowa City, IA, USA
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Corentin Affortit
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Paul T Ranum
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia Research Institute, Philadelphia, PA, USA
| | - Cody West
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - William D Walls
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Hidekane Yoshimura
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Department of Otorhinolaryngology - Head and Neck Surgery, Shinshu University School of Medicine, Matsumoto, Japan
| | - Jian Q Shao
- Central Microscopy Research Facility, University of Iowa, Iowa City, IA, USA
| | - Brian Mostaert
- Department of Otolaryngology, Head and Neck Surgery, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Richard J H Smith
- Roy J. Carver Department of Biomedical Engineering, College of Engineering, University of Iowa, University of Iowa, Iowa City, IA, USA.
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
- Department of Otolaryngology, Head and Neck Surgery, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
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15
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Watanabe H, Ito T, Aoki N, Bai J, Honda K, Kawashima Y, Fujikawa T, Ikeda T, Tsutsumi T. Quantitative analysis and correlative evaluation of video-oculography, micro-computed tomography, and histopathology in Pendrin-null mice. Neurobiol Dis 2023; 183:106194. [PMID: 37295562 DOI: 10.1016/j.nbd.2023.106194] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/12/2023] Open
Abstract
Patients with SLC26A4 mutations exhibit highly variable hearing loss and vestibular dysfunction. Although Slc26a4 mutant mice similarly exhibit vestibular deficits, including circling behavior, head tilting, and torticollis, the underlying pathogenesis of the vestibular symptoms remains unclear, hindering its effective management for patients with SLC26A4 mutations. In this study, we evaluated the equilibrium function using the inspection equipment, which can record eye movements against rotational, gravitational, and thermal stimulations. Moreover, we correlated the degree of functional impairment with the morphological alterations observed in Slc26a4Δ/Δ mice. The rotational stimulus and ice water caloric tests revealed considerable impairment of the semicircular canal, while the tilted gravitational stimulus test showed a severe functional decline of the otolithic system in Slc26a4Δ/Δ mice. Generally, the degree of impairment was more severe in circling Slc26a4Δ/Δ mice than in non-circling Slc26a4Δ/Δ mice. In non-circling Slc26a4Δ/Δ mice, the semicircular canal function was normal. Micro-computed tomography results showed enlargement of the vestibular aqueduct and bony semicircular canals but no correlative relationship between the severity of the caloric response and the size of bony labyrinths. Giant otoconia and a significant decrease in total otolith volume in the saccule and utricle were observed in Slc26a4Δ/Δ mice. However, the giant otoconia were not overly dislocated in the bony otolithic system and ectopic otoconia were absent in the semicircular canal. The number and morphology of the utricular hair cells in Slc26a4Δ/Δ mice were not significantly reduced compared to those in Slc26a4Δ/+ mice. Collectively, we can conclude that vestibular impairments are mainly associated with otoconia formation and morphology rather than hair cell degeneration. In addition, severe disturbances of semicircular canals cause circling behavior in Slc26a4Δ/Δ mice. Our comprehensive morphological and functional assessments apply to mouse models of other genetic diseases with vestibular impairment.
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Affiliation(s)
- Hiroki Watanabe
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan; Department of Otorhinolaryngology, Tokyo Metropolitan Institute for Geriatrics and Gerontology, 35-2 Sakaecho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Taku Ito
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
| | - Natsuki Aoki
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Jing Bai
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Keiji Honda
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Yoshiyuki Kawashima
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Taro Fujikawa
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Takuo Ikeda
- Department of Otorhinolaryngology, Tsudumigaura Medical Center for Children with disabilities, 752-4 Kume, Shunan-shi, Yamaguchi 745-0801, Japan
| | - Takeshi Tsutsumi
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
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16
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Vitzthum H, Koch M, Eckermann L, Svendsen SL, Berg P, Hübner CA, Wagner CA, Leipziger J, Meyer-Schwesinger C, Ehmke H. The AE4 transporter mediates kidney acid-base sensing. Nat Commun 2023; 14:3051. [PMID: 37236964 DOI: 10.1038/s41467-023-38562-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 05/05/2023] [Indexed: 05/28/2023] Open
Abstract
The kidney plays a key role in the correction of systemic acid-base imbalances. Central for this regulation are the intercalated cells in the distal nephron, which secrete acid or base into the urine. How these cells sense acid-base disturbances is a long-standing question. Intercalated cells exclusively express the Na+-dependent Cl-/HCO3- exchanger AE4 (Slc4a9). Here we show that AE4-deficient mice exhibit a major dysregulation of acid-base balance. By combining molecular, imaging, biochemical and integrative approaches, we demonstrate that AE4-deficient mice are unable to sense and appropriately correct metabolic alkalosis and acidosis. Mechanistically, a lack of adaptive base secretion via the Cl-/HCO3- exchanger pendrin (Slc26a4) is the key cellular cause of this derailment. Our findings identify AE4 as an essential part of the renal sensing mechanism for changes in acid-base status.
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Affiliation(s)
- H Vitzthum
- Center for Experimental Medicine, Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - M Koch
- Center for Experimental Medicine, Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - L Eckermann
- Center for Experimental Medicine, Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - S L Svendsen
- Department of Biomedicine, Physiology, Health, Aarhus University, Aarhus, Denmark
| | - P Berg
- Department of Biomedicine, Physiology, Health, Aarhus University, Aarhus, Denmark
| | - C A Hübner
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - C A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - J Leipziger
- Department of Biomedicine, Physiology, Health, Aarhus University, Aarhus, Denmark
| | - C Meyer-Schwesinger
- Center for Experimental Medicine, Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - H Ehmke
- Center for Experimental Medicine, Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
- German Center for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany.
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17
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Liu Q, Zhang X, Huang H, Chen Y, Wang F, Hao A, Zhan W, Mao Q, Hu Y, Han L, Sun Y, Zhang M, Liu Z, Li GL, Zhang W, Shu Y, Sun L, Chen Z. Asymmetric pendrin homodimer reveals its molecular mechanism as anion exchanger. Nat Commun 2023; 14:3012. [PMID: 37230976 DOI: 10.1038/s41467-023-38303-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 04/23/2023] [Indexed: 05/27/2023] Open
Abstract
Pendrin (SLC26A4) is an anion exchanger expressed in the apical membranes of selected epithelia. Pendrin ablation causes Pendred syndrome, a genetic disorder associated with sensorineural hearing loss, hypothyroid goiter, and reduced blood pressure. However its molecular structure has remained unknown, limiting our understanding of the structural basis of transport. Here, we determine the cryo-electron microscopy structures of mouse pendrin with symmetric and asymmetric homodimer conformations. The asymmetric homodimer consists of one inward-facing protomer and the other outward-facing protomer, representing coincident uptake and secretion- a unique state of pendrin as an electroneutral exchanger. The multiple conformations presented here provide an inverted alternate-access mechanism for anion exchange. The structural and functional data presented here disclose the properties of an anion exchange cleft and help understand the importance of disease-associated variants, which will shed light on the pendrin exchange mechanism.
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Affiliation(s)
- Qianying Liu
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Xiang Zhang
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Hui Huang
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yuxin Chen
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Fang Wang
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Aihua Hao
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Wuqiang Zhan
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Qiyu Mao
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yuxia Hu
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Lin Han
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yifang Sun
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Meng Zhang
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Zhimin Liu
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Geng-Lin Li
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Weijia Zhang
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yilai Shu
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China.
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China.
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China.
- Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China.
| | - Lei Sun
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China.
- Shanghai Institute of Infectious Disease and Biosecurity, Shanghai, 200032, China.
- Shanghai Key Laboratory of Medical Epigenetics, Shanghai, 200032, China.
| | - Zhenguo Chen
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China.
- Shanghai Institute of Infectious Disease and Biosecurity, Shanghai, 200032, China.
- Shanghai Key Laboratory of Medical Epigenetics, Shanghai, 200032, China.
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18
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Ferdaus MZ, Terker AS, Koumangoye R, Wall SM, Delpire E. Bicarbonate is the primary inducer of KCC3a expression in renal cortical B-type intercalated cells. Am J Physiol Cell Physiol 2023; 324:C1171-C1178. [PMID: 37036298 PMCID: PMC10191129 DOI: 10.1152/ajpcell.00094.2023] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [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: 03/14/2023] [Revised: 03/30/2023] [Accepted: 03/30/2023] [Indexed: 04/11/2023]
Abstract
A primary function of intercalated cells in the distal tubule of the kidney is to maintain pH homeostasis. For example, type B intercalated cells secrete bicarbonate largely through the action of the apical Cl-/HCO3- exchanger, pendrin, which helps correct metabolic alkalosis. Since both the K-Cl cotransporter, KCC3a and pendrin colocalize to the apical region of type B and non-A, non-B intercalated cells and since both are upregulated in models of metabolic alkalosis, such as with dietary NaHCO3 loading, we raised the possibility that apical KCC3a facilitates pendrin-mediated bicarbonate secretion, such as through apical Cl- recycling. The purpose of this study was to determine if KCC3a abundance changes through intake of bicarbonate alone or through bicarbonate plus its accompanying cation, and if it requires a direct interaction with pendrin or the renin-angiotensin-aldosterone system. We observed that KCC3a protein abundance, but not mRNA, increases in a mouse model of metabolic alkalosis, achieved with dietary NaHCO3 or KHCO3 intake. Bicarbonate ion increases KCC3a abundance, both in vivo and in vitro, independently of the accompanying cation. Moreover, bicarbonate intake upregulates KCC3a independently of aldosterone or angiotensin II. Since NaHCO3 intake increased KCC3a abundance in wild-type as well as in pendrin knockout mice, this KCC3a upregulation by bicarbonate does not depend on a direct interaction with pendrin. We conclude that increased extracellular bicarbonate, as observed in models of metabolic alkalosis, directly raises KCC3a abundance independently of angiotensin II, aldosterone, or changes in KCC3a transcription and does not involve a direct interaction with pendrin.NEW & NOTEWORTHY KCC3a expression is stimulated in alkalemia. This paper shows that bicarbonate itself is mediating this effect through a posttranscriptional mechanism. The paper also shows that this phenomenon is not mediated by aldosterone or angiotensin II.
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Affiliation(s)
- Mohammed Z Ferdaus
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Andrew S Terker
- Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Rainelli Koumangoye
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Susan M Wall
- Division of Nephrology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
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19
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Loffing J, Pech V, Loffing-Cueni D, Abood DC, Kim YH, Chen C, Pham TD, Verlander JW, Wall SM. Pendrin abundance, subcellular distribution, and function are unaffected by either αENaC gene ablation or by increasing ENaC channel activity. Pflugers Arch 2023; 475:607-620. [PMID: 36977894 PMCID: PMC10105674 DOI: 10.1007/s00424-023-02797-w] [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: 11/14/2022] [Revised: 01/20/2023] [Accepted: 02/13/2023] [Indexed: 03/30/2023]
Abstract
The intercalated cell Cl-/HCO3- exchanger, pendrin, modulates ENaC subunit abundance and function. Whether ENaC modulates pendrin abundance and function is however unknown. Because αENaC mRNA has been detected in pendrin-positive intercalated cells, we hypothesized that ENaC, or more specifically the αENaC subunit, modulates intercalated cell function. The purpose of this study was therefore to determine if αENaC is expressed at the protein level in pendrin-positive intercalated cells and to determine if αENaC gene ablation or constitutively upregulating ENaC activity changes pendrin abundance, subcellular distribution, and/or function. We observed diffuse, cytoplasmic αENaC label in pendrin-positive intercalated cells from both mice and rats, with much lower label intensity in pendrin-negative, type A intercalated cells. However, while αENaC gene ablation within principal and intercalated cells of the CCD reduced Cl- absorption, it did not change pendrin abundance or subcellular distribution in aldosterone-treated mice. Further experiments used a mouse model of Liddle's syndrome to explore the effect of increasing ENaC channel activity on pendrin abundance and function. The Liddle's variant did not increase either total or apical plasma membrane pendrin abundance in aldosterone-treated or in NaCl-restricted mice. Similarly, while the Liddle's mutation increased total Cl- absorption in CCDs from aldosterone-treated mice, it did not significantly affect the change in Cl- absorption seen with pendrin gene ablation. We conclude that in rats and mice, αENaC localizes to pendrin-positive ICs where its physiological role remains to be determined. While pendrin modulates ENaC abundance, subcellular distribution, and function, ENaC does not have a similar effect on pendrin.
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Affiliation(s)
- Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.
| | - Vladimir Pech
- Division of Renal Medicine, Department of Medicine, Emory University, Atlanta, GA, 30322, USA
| | | | - Delaney C Abood
- Division of Renal Medicine, Department of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Young Hee Kim
- Division of Renal Medicine, Department of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Chao Chen
- The Division of Nephrology, Hypertension and Renal Transplantation, The University of Florida College of Medicine, Gainesville, FL, USA
| | - Truyen D Pham
- Division of Renal Medicine, Department of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Jill W Verlander
- The Division of Nephrology, Hypertension and Renal Transplantation, The University of Florida College of Medicine, Gainesville, FL, USA
| | - Susan M Wall
- Division of Renal Medicine, Department of Medicine, Emory University, Atlanta, GA, 30322, USA.
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20
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Cobb LH, Bailey VO, Liu YF, Teixido MT, Rizk HG. Relationship of vitamin D levels with clinical presentation and recurrence of BPPV in a Southeastern United States institution. Auris Nasus Larynx 2023; 50:70-80. [PMID: 35659787 DOI: 10.1016/j.anl.2022.05.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [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: 02/09/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 01/28/2023]
Abstract
OBJECTIVE To examine the relationship of 25hydroxyvitamin D serum levels with BPPV incidence and recurrence rates. METHODS A retrospective cross-sectional, case-controlled study with follow-up phone survey was performed on patients diagnosed with BPPV between 05/2017-05/2020, who had available 25hydroxyvitamin D serology. Patients were seen at a multidisciplinary, vestibular-focused, neurotology clinic at a tertiary referral center. Controls consisted of subjects from the National Health and Nutrition Examination Survey (NHANES), and a locoregional age, sex, and race-matched group of patients from our institution. RESULTS Our BPPV cohort consisted of 173 patients (mean age 66.2 ± 11.8 years), who were predominately female (75.7%) and Caucasian (76.3%). Almost all age subgroups (BPPV, NHANES, and locoregional groups) ≤60 years old had insufficient levels of vitamin D. However, the overall BPPV cohort had a significantly higher vitamin D level than the NHANES control (31.4 ± 16.5 v. 26.0 ± 11.2 ng/mL, d=0.474 [0.323, 0.626]). There was no significant difference when compared to the overall locoregional control (31.4 ± 20.5 ng/mL). Migraines were significantly correlated to increased BPPV recurrence rates on univariate (beta=0.927, p=0.037, 95% CI: [0.057, 1.798]) and multiple regression analyses (beta=0.231, 95% CI: [0.024, 2.029], p=0.045). Furthermore, patients with BPPV recurrences had significantly lower levels of vitamin D at initial presentation when compared to patients with no recurrences (29.0 ± 12.0 v. 37.6 ± 18.3 ng/mL, d=0.571[0.139,1.001]). CONCLUSION Many BPPV patients in our cohort had insufficient vitamin D levels, and patients with BPPV recurrences had insufficient and significantly lower vitamin D levels than those without. As a readily available and affordable supplement, vitamin D may be used as an adjunct treatment but prospective studies should be done to confirm if it can prevent or reduce recurrence.
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Affiliation(s)
- Leah H Cobb
- Department of Otolaryngology; Medical University of South Carolina, Charleston, SC, USA
| | - Victoria O Bailey
- Department of Otolaryngology; Medical University of South Carolina, Charleston, SC, USA
| | - Yuan F Liu
- Department of Otolaryngology, Head and Neck Surgery, Loma Linda University Health, Loma Linda, CA, USA
| | - Michael T Teixido
- Department of Otolaryngology, University of Pennsylvania, Philadelphia, PA, USA
| | - Habib G Rizk
- Department of Otolaryngology; Medical University of South Carolina, Charleston, SC, USA.
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21
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Choi HJ, Kanwal S, Hameed R, Tamanna N, Perveen S, Mahreen H, Son W, Lee KS, Chung KW. Biallelic mutations in pakistani families with autosomal recessive prelingual nonsyndromic hearing loss. Genes Genomics 2023; 45:145-56. [PMID: 36472766 DOI: 10.1007/s13258-022-01349-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 11/24/2022] [Indexed: 12/12/2022]
Abstract
BACKGROUND Nonsyndromic autosomal recessive hearing loss (DFNB) is an etiologically heterogeneous disorder group showing a wide spectrum of onset ages and severity. DFNB genes are very diverse in their types and functions, making molecular diagnosis difficult. DFNB is particularly frequent in Pakistan, which may be partly due to consanguinity. OBJECTIVE This study was performed to determine the genetic causes in Pakistani DFNB families with prelingual onset and to establish genotype-phenotype correlation. METHODS Whole exome sequencing and subsequent genetic analysis were performed for 11 Pakistani DFNB families including eight consanguineous families. RESULTS We identified eight pathogenic or likely pathogenic mutations in LOXHD1, GJB2, SLC26A4, MYO15A, and TMC1 from six families. The GJB2 mutations were identified in two families each with compound heterozygous mutations and a homozygous mutation. The compound heterozygous mutations in LOXHD1 ([p.D278Y] + [p.D1219E]) and GJB2 [p.M1?] + [p.G12Vfs*2]) were novel. The four missense or start-loss mutations were located at well conserved residues, and most in silico analysis predicted their pathogenicity. In addition to causative mutations, we found compound heterozygous mutations in PTPRQ as variants of uncertain significance. CONCLUSION This study identified biallelic mutations as the underlying cause of early onset DFNB in six Pakistani families. This study will be helpful in providing an exact molecular diagnosis and treatment of prelingual onset deafness patients.
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22
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Durán-Alonso MB, Petković H. Induced Pluripotent Stem Cells, a Stepping Stone to In Vitro Human Models of Hearing Loss. Cells 2022; 11:3331. [PMID: 36291196 DOI: 10.3390/cells11203331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 10/05/2022] [Accepted: 10/14/2022] [Indexed: 11/28/2022] Open
Abstract
Hearing loss is the most prevalent sensorineural impairment in humans. Yet despite very active research, no effective therapy other than the cochlear implant has reached the clinic. Main reasons for this failure are the multifactorial nature of the disorder, its heterogeneity, and a late onset that hinders the identification of etiological factors. Another problem is the lack of human samples such that practically all the work has been conducted on animals. Although highly valuable data have been obtained from such models, there is the risk that inter-species differences exist that may compromise the relevance of the gathered data. Human-based models are therefore direly needed. The irruption of human induced pluripotent stem cell technologies in the field of hearing research offers the possibility to generate an array of otic cell models of human origin; these may enable the identification of guiding signalling cues during inner ear development and of the mechanisms that lead from genetic alterations to pathology. These models will also be extremely valuable when conducting ototoxicity analyses and when exploring new avenues towards regeneration in the inner ear. This review summarises some of the work that has already been conducted with these cells and contemplates future possibilities.
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23
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Merakchi K, Djerbib S, Soleimani M, Dumont JE, Miot F, De Deken X. Murine Thyroid IL-4 Expression Worsens Hypothyroidism on Iodine Restriction and Mitigates Graves Disease Development. Endocrinology 2022; 163:6650252. [PMID: 35881515 DOI: 10.1210/endocr/bqac107] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Indexed: 11/19/2022]
Abstract
Cytokines are known to perturb thyroid function and the role of interleukin-4 (IL-4) in the pathogenesis of Graves disease (GD) remains controversial. In our mouse model overexpressing IL-4 in thyrocytes (Thyr-IL4), we have reported that adult mice preserved normal serum thyroxine despite an iodide uptake defect. In the present work, we evaluated if iodine restriction could uncover the thyroid deficiency in Thyr-IL4 animals as well as the role of pendrin overexpression as a compensatory mechanism. Moreover, using an experimental model of GD we investigated the effect of a local expression of IL-4 on the incidence of hyperthyroidism. Thyr-IL4 mice developed more rapidly elevated serum thyrotropin under low-iodine supply with thyroid enlargement and classical histological modifications. These hallmarks of hypothyroidism were all enhanced in Thyr-IL4 mice with complete pendrin invalidation. Following immunization, a lower proportion of Thyr-IL4 animals developed hyperthyroidism. Surprisingly, immunized Thyr-IL4 animals presented numerous leukocyte infiltrates, associated with increased intrathyroidal expression of IFN-γ. We have demonstrated that thyroid deficiency in Thyr-IL4 mice is partially compensated for by the excessive iodide content of the standard chow and the overexpression of pendrin in these animals. Furthermore, we have shown that the local expression of IL-4 in the thyroid attenuates GD progression, which was associated with enhanced thyroid infiltration by immune cells that could negatively affect thyroid function.
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Affiliation(s)
- Karima Merakchi
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Sami Djerbib
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Manoocher Soleimani
- Department of Medicine, University of New Mexico, School of Medicine, Albuquerque, New Mexico 87106, USA
| | - Jacques-Emile Dumont
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Françoise Miot
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Xavier De Deken
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
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24
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Yamaguchi N, Suzuki A, Yoshida A, Tanaka T, Aoyama K, Oishi H, Hara Y, Ogi T, Amano I, Kameo S, Koibuchi N, Shibata Y, Ugawa S, Mizuno H, Saitoh S. The iodide transporter Slc26a7 impacts thyroid function more strongly than Slc26a4 in mice. Sci Rep 2022; 12:11259. [PMID: 35788623 PMCID: PMC9253019 DOI: 10.1038/s41598-022-15151-4] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 06/20/2022] [Indexed: 11/09/2022] Open
Abstract
SLC26A4 is a known iodide transporter, and is localized at the apical membrane of thyrocytes. Previously, we reported that SLC26A7 is also involved in iodide transport and that Slc26a7 is a novel causative gene for congenital hypothyroidism. However, its detailed role in vivo remains to be elucidated. We generated mice that were deficient in Slc26a7 and Slc26a4 to delineate differences and associations in their roles in iodide transport. Slc26a7-/- mice showed goitrous congenital hypothyroidism and mild growth failure on a normal diet. Slc26a7-/- mice with a low iodine environment showed marked growth failure. In contrast, Slc26a4-/- mice showed no growth failure and hypothyroidism in the same low iodine environment. Double-deficient mice showed more severe growth failure than Slc26a7-/- mice. RNA-seq analysis revealed that the number of differentially expressed genes (DEGs) in Slc26a7-/- mice was significantly higher than that in Slc26a4-/- mice. These indicate that SLC26A7 is more strongly involved in iodide transport and the maintenance of thyroid function than SLC26A4.
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Affiliation(s)
- Naoya Yamaguchi
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Atsushi Suzuki
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Aya Yoshida
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Tatsushi Tanaka
- Department of Pediatrics, Toyohashi Municipal Hospital, Toyohashi, Japan
| | - Kohei Aoyama
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan.
| | - Hisashi Oishi
- Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Yuichiro Hara
- Department of Genetics, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Human Genetics and Molecular Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tomoo Ogi
- Department of Genetics, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Human Genetics and Molecular Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Izuki Amano
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Satomi Kameo
- Department of Nutrition, Koshien University, Takarazuka, Japan
| | - Noriyuki Koibuchi
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Yasuhiro Shibata
- Department of Anatomy and Neuroscience, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Shinya Ugawa
- Department of Anatomy and Neuroscience, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Haruo Mizuno
- Department of Pediatrics, Fujita Health University School of Medicine, Toyoake, Japan
| | - Shinji Saitoh
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
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25
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Maudoux A, Vitry S, El-Amraoui A. Vestibular Deficits in Deafness: Clinical Presentation, Animal Modeling, and Treatment Solutions. Front Neurol 2022; 13:816534. [PMID: 35444606 PMCID: PMC9013928 DOI: 10.3389/fneur.2022.816534] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/23/2022] [Indexed: 11/13/2022] Open
Abstract
The inner ear is responsible for both hearing and balance. These functions are dependent on the correct functioning of mechanosensitive hair cells, which convert sound- and motion-induced stimuli into electrical signals conveyed to the brain. During evolution of the inner ear, the major changes occurred in the hearing organ, whereas the structure of the vestibular organs remained constant in all vertebrates over the same period. Vestibular deficits are highly prevalent in humans, due to multiple intersecting causes: genetics, environmental factors, ototoxic drugs, infections and aging. Studies of deafness genes associated with balance deficits and their corresponding animal models have shed light on the development and function of these two sensory systems. Bilateral vestibular deficits often impair individual postural control, gaze stabilization, locomotion and spatial orientation. The resulting dizziness, vertigo, and/or falls (frequent in elderly populations) greatly affect patient quality of life. In the absence of treatment, prosthetic devices, such as vestibular implants, providing information about the direction, amplitude and velocity of body movements, are being developed and have given promising results in animal models and humans. Novel methods and techniques have led to major progress in gene therapies targeting the inner ear (gene supplementation and gene editing), 3D inner ear organoids and reprograming protocols for generating hair cell-like cells. These rapid advances in multiscale approaches covering basic research, clinical diagnostics and therapies are fostering interdisciplinary research to develop personalized treatments for vestibular disorders.
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Affiliation(s)
- Audrey Maudoux
- Unit Progressive Sensory Disorders, Pathophysiology and Therapy, Institut Pasteur, Institut de l'Audition, Université de Paris, INSERM-UMRS1120, Paris, France.,Center for Balance Evaluation in Children (EFEE), Otolaryngology Department, Assistance Publique des Hôpitaux de Paris, Robert-Debré University Hospital, Paris, France
| | - Sandrine Vitry
- Unit Progressive Sensory Disorders, Pathophysiology and Therapy, Institut Pasteur, Institut de l'Audition, Université de Paris, INSERM-UMRS1120, Paris, France
| | - Aziz El-Amraoui
- Unit Progressive Sensory Disorders, Pathophysiology and Therapy, Institut Pasteur, Institut de l'Audition, Université de Paris, INSERM-UMRS1120, Paris, France
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26
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Berg P, Andersen JF, Sørensen MV, Wang T, Malte H, Leipziger J. Alkalosis-induced hypoventilation in cystic fibrosis: The importance of efficient renal adaptation. Proc Natl Acad Sci U S A 2022; 119:e2116836119. [PMID: 35173044 DOI: 10.1073/pnas.2116836119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2022] [Indexed: 11/18/2022] Open
Abstract
The lungs and kidneys are pivotal organs in the regulation of body acid-base homeostasis. In cystic fibrosis (CF), the impaired renal ability to excrete an excess amount of HCO3 - into the urine leads to metabolic alkalosis [P. Berg et al., J. Am. Soc. Nephrol. 31, 1711-1727 (2020); F. Al-Ghimlas, M. E. Faughnan, E. Tullis, Open Respir. Med. J. 6, 59-62 (2012)]. This is caused by defective HCO3 - secretion in the β-intercalated cells of the collecting duct that requires both the cystic fibrosis transmembrane conductance regulator (CFTR) and pendrin for normal function [P. Berg et al., J. Am. Soc. Nephrol. 31, 1711-1727 (2020)]. We studied the ventilatory consequences of acute oral base loading in normal, pendrin knockout (KO), and CFTR KO mice. In wild-type mice, oral base loading induced a dose-dependent metabolic alkalosis, fast urinary removal of base, and a moderate base load did not perturb ventilation. In contrast, CFTR and pendrin KO mice, which are unable to rapidly excrete excess base into the urine, developed a marked and transient depression of ventilation when subjected to the same base load. Therefore, swift renal base elimination in response to an acute oral base load is a necessary physiological function to avoid ventilatory depression. The transient urinary alkalization in the postprandial state is suggested to have evolved for proactive avoidance of hypoventilation. In CF, metabolic alkalosis may contribute to the commonly reduced lung function via a suppression of ventilatory drive.
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27
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Abstract
Intercalated cells make up about a third of all cells within the connecting tubule and the collecting duct and are subclassified as type A, type B and non-A, non-B based on the subcellular distribution of the H+-ATPase, which dictates whether it secretes H+ or HCO3-. Type B intercalated cells mediate Cl- absorption and HCO3- secretion, which occurs largely through the anion exchanger pendrin. Pendrin is stimulated by angiotensin II via the angiotensin type 1a receptor and by aldosterone through MR (mineralocorticoid receptor). Aldosterone stimulates pendrin expression and function, in part, through the alkalosis it generates. Pendrin-mediated HCO3- secretion increases in models of metabolic alkalosis, which attenuates the alkalosis. However, pendrin-positive intercalated cells also regulate blood pressure, at least partly, through pendrin-mediated Cl- absorption and through their indirect effect on the epithelial Na+ channel, ENaC. This aldosterone-induced increase in pendrin secondarily stimulates ENaC, thereby contributing to the aldosterone pressor response. This review describes the contribution of pendrin-positive intercalated cells to Na+, K+, Cl- and acid-base balance.
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Affiliation(s)
- Susan M Wall
- Department of Medicine, Emory University School of Medicine, Atlanta, GA
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28
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Abstract
Cystic fibrosis (CF) is caused by defects in an anion channel, the cystic fibrosis transmembrane conductance regulator (CFTR). Recently, a new airway epithelial cell type has been discovered and dubbed the pulmonary ionocyte. Unexpectedly, these ionocytes express higher levels of CFTR than any other airway epithelial cell type. However, ionocytes are not the sole CFTR-expressing airway epithelial cells, and CF-associated disease genes are in fact expressed in multiple airway epithelial cell types. The experimental depletion of ionocytes perturbs epithelial physiology in the mouse trachea, but the role of these rare cells in the pathogenesis of human CF remains mysterious. Ionocytes have been described in diverse tissues(kidney and inner ear) and species (frog and fish). We draw on these prior studies to suggest potential roles of airway ionocytes in health and disease. A complete understanding of ionocytes in the mammalian airway will ultimately depend on cell type-specific genetic manipulation.
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Affiliation(s)
- Viral S Shah
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA; , , , ,
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Raghu R Chivukula
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA; , , , ,
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA
| | - Brian Lin
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA; , , , ,
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
- Harvard Stem Cell Institute, Cambridge, Massachusetts 02138, USA
| | - Avinash Waghray
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA; , , , ,
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
- Harvard Stem Cell Institute, Cambridge, Massachusetts 02138, USA
| | - Jayaraj Rajagopal
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA; , , , ,
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
- Harvard Stem Cell Institute, Cambridge, Massachusetts 02138, USA
- Klarman Cell Observatory, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
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29
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Jones A. A case of 7q21.3q31.1 deletion in a preterm boy with feeding intolerance and cyanotic episodes. J Clin Neonatol 2022. [DOI: 10.4103/jcn.jcn_119_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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30
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Li M, Leng Y, Liu B. Clinical Implication of Caloric and Video Head Impulse Tests for Patients With Enlarged Vestibular Aqueduct Presenting With Vertigo. Front Neurol 2021; 12:717035. [PMID: 34707555 PMCID: PMC8542699 DOI: 10.3389/fneur.2021.717035] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 09/10/2021] [Indexed: 11/25/2022] Open
Abstract
Background: By examining the clinical features and results of video head impulse test (vHIT) and caloric tests in patients with enlarged vestibular aqueduct (EVA) presenting with vertigo, we aimed to investigate the function of angular vestibulo-ocular reflex (VOR) and its clinical implications. Methods: Nine patients with EVA manifesting with vertigo were enrolled. The medical history, audiological examination, imaging, and the results of the caloric test and the vHIT were analyzed. Results: Of the nine patients with EVA (eight bilateral and one unilateral case), five were pediatric cases. All 17 ears exhibited sensorineural hearing loss (SNHL). Enlarged vestibular aqueduct patients can present with recurrent (seven cases) or single (two cases) vertigo attack, trauma-induced (two cases), or spontaneous (seven cases) vertigo. Diminished caloric responses were observed in 77.8% (7/9) of the patients (four cases unilaterally and three bilaterally), while unilateral abnormal vHIT results in 11.1% (1/9) patients. Abnormal caloric and normal horizontal vHIT responses were found in 66.7% (6/9) of EVA patients. Conclusions: Vestibular manifestations in EVA are diverse. Enlarged vestibular aqueduct patients with vertigo can present with a reduced caloric response and normal horizontal vHIT, and this pattern of angular VOR impairment was also found in other hydropic ear diseases.
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Affiliation(s)
- Ming Li
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yangming Leng
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bo Liu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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31
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Hu CJ, Lu YC, Tsai CY, Chan YH, Lin PH, Lee YS, Yu IS, Lin SW, Liu TC, Hsu CJ, Yang TH, Cheng YF, Wu CC. Insights into phenotypic differences between humans and mice with p.T721M and other C-terminal variants of the SLC26A4 gene. Sci Rep 2021; 11:20983. [PMID: 34697379 PMCID: PMC8545921 DOI: 10.1038/s41598-021-00448-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 06/01/2021] [Accepted: 09/22/2021] [Indexed: 11/17/2022] Open
Abstract
Recessive variants of the SLC26A4 gene are an important cause of hereditary hearing impairment. Several transgenic mice with different Slc26a4 variants have been generated. However, none have recapitulated the auditory phenotypes in humans. Of the SLC26A4 variants identified thus far, the p.T721M variant is of interest, as it appears to confer a more severe pathogenicity than most of the other missense variants, but milder pathogenicity than non-sense and frameshift variants. Using a genotype-driven approach, we established a knock-in mouse model homozygous for p.T721M. To verify the pathogenicity of p.T721M, we generated mice with compound heterozygous variants by intercrossing Slc26a4+/T721M mice with Slc26a4919-2A>G/919-2A>G mice, which segregated the c.919-2A > G variant with abolished Slc26a4 function. We then performed serial audiological assessments, vestibular evaluations, and inner ear morphological studies. Surprisingly, both Slc26a4T721M/T721M and Slc26a4919-2A>G/T721M showed normal audiovestibular functions and inner ear morphology, indicating that p.T721M is non-pathogenic in mice and a single p.T721M allele is sufficient to maintain normal inner ear physiology. The evidence together with previous reports on mouse models with Slc26a4 p.C565Y and p.H723R variants, support our speculation that the absence of audiovestibular phenotypes in these mouse models could be attributed to different protein structures at the C-terminus of human and mouse pendrin.
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Affiliation(s)
- Chin-Ju Hu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.,Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA, 02115, USA
| | - Ying-Chang Lu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan
| | - Cheng-Yu Tsai
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan
| | - Yen-Hui Chan
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.,Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, 427, Taiwan
| | - Pei-Hsuan Lin
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan
| | - Yi-Shan Lee
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan
| | - I-Shing Yu
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center for Medical Excellence, National Taiwan University, Taipei, 100, Taiwan
| | - Shu-Wha Lin
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center for Medical Excellence, National Taiwan University, Taipei, 100, Taiwan
| | - Tien-Chen Liu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.,Department of Otolaryngology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - Chuan-Jen Hsu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.,Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, 427, Taiwan
| | - Ting-Hua Yang
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.
| | - Yen-Fu Cheng
- Department of Medical Research, Taipei Veteran General Hospital, 201, Sec.2, Shi-Pai Rd, Taipei, 112, Taiwan. .,Department of Otolaryngology-Head and Neck Surgery, Taipei Veteran General Hospital, Taipei, 112, Taiwan. .,School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan.
| | - Chen-Chi Wu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan. .,Department of Otolaryngology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan. .,Department of Medical Research, National Taiwan University Hospital Hsin-Chu Branch, Hsinchu, 302, Taiwan.
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32
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Ito T, Fujikawa T, Honda K, Makabe A, Watanabe H, Bai J, Kawashima Y, Miwa T, Griffith AJ, Tsutsumi T. Cochlear Pathomorphogenesis of Incomplete Partition Type II in Slc26a4-Null Mice. J Assoc Res Otolaryngol 2021; 22:681-691. [PMID: 34622375 DOI: 10.1007/s10162-021-00812-4] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 08/09/2021] [Indexed: 11/24/2022] Open
Abstract
Incomplete partition type II (IP-II) is frequently identified in ears with SLC26A4 mutations. Cochleae with IP-II are generally observed to have 1½ turns; the basal turns are normally formed, and the apical turn is dilated or cystic. The objective of this study was to characterize the pathomorphogenesis of the IP-II cochlear anomaly in Slc26a4-null mice. Otic capsules were dissected from Slc26a4Δ/+ and Slc26a4Δ/Δ mice at 1 and 8 days of age and at 1 and 3 months of age. X-ray micro-computed tomography was used to image samples. We used a multiplanar view and three-dimensional reconstructed models to calculate the cochlear duct length, cochlear turn rotation angle, and modiolus tilt angle. The number of inner hair cells was counted, and the length of the cochlear duct was measured in a whole-mount preparation of the membranous labyrinth. X-ray micro-computed tomography mid-modiolar planar views demonstrated cystic apical turns in Slc26a4Δ/Δ mice resulting from the loss or deossification of the interscalar septum, which morphologically resembles IP-II in humans. Planes vertical to the modiolus showed a similar mean rotation angle between Slc26a4Δ/+ and Slc26a4Δ/Δ mice. In contrast, the mean cochlear duct length and mean number of inner hair cells in Slc26a4Δ/Δ mice were significantly smaller than in Slc26a4Δ/+ mice. In addition, there were significant differences in the mean tilt angle and mean width of the modiolus. Our analysis of Slc26a4-null mice suggests that IP-II in humans reflects loss or deossification of the interscalar septum but not a decreased number of cochlear turns.
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Affiliation(s)
- Taku Ito
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan.
| | - Taro Fujikawa
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
| | - Keiji Honda
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
| | - Ayane Makabe
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
| | - Hiroki Watanabe
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
| | - Jing Bai
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
| | - Yoshiyuki Kawashima
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
| | - Toru Miwa
- Department of Otolaryngology, Tazuke Kofukai Medical Research Institute, Kitano Hospital, 2-4-20 Ogimachi, Kita-ku, Osaka, 530-8480, Japan
| | - Andrew J Griffith
- Molecular Biology and Genetics Section, National Institute On Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA.,Departments of Otolaryngology and Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Takeshi Tsutsumi
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
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Peusner KD, Bell NM, Hirsch JC, Beraneck M, Popratiloff A. Understanding the Pathophysiology of Congenital Vestibular Disorders: Current Challenges and Future Directions. Front Neurol 2021; 12:708395. [PMID: 34589045 PMCID: PMC8475631 DOI: 10.3389/fneur.2021.708395] [Citation(s) in RCA: 1] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 08/13/2021] [Indexed: 12/13/2022] Open
Abstract
In congenital vestibular disorders (CVDs), children develop an abnormal inner ear before birth and face postnatal challenges to maintain posture, balance, walking, eye-hand coordination, eye tracking, or reading. Only limited information on inner ear pathology is acquired from clinical imaging of the temporal bone or studying histological slides of the temporal bone. A more comprehensive and precise assessment and determination of the underlying mechanisms necessitate analyses of the disorders at the cellular level, which can be achieved using animal models. Two main criteria for a suitable animal model are first, a pathology that mirrors the human disorder, and second, a reproducible experimental outcome leading to statistical power. With over 40 genes that affect inner ear development, the phenotypic abnormalities resulting from congenital vestibular disorders (CVDs) are highly variable. Nonetheless, there is a large subset of CVDs that form a common phenotype of a sac-like inner ear with the semicircular canals missing or dysplastic, and discrete abnormalities in the vestibular sensory organs. We have focused the review on this subset, but to advance research on CVDs we have added other CVDs not forming a sac-like inner ear. We have included examples of animal models used to study these CVDs. Presently, little is known about the central pathology resulting from CVDs at the cellular level in the central vestibular neural network, except for preliminary studies on a chick model that show significant loss of second-order, vestibular reflex projection neurons.
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Affiliation(s)
- Kenna D Peusner
- Department of Neurology, The George Washington University School of Medicine and Health Sciences, Washington, DC, United States
| | - Nina M Bell
- Department of Neurology, The George Washington University School of Medicine and Health Sciences, Washington, DC, United States
| | - June C Hirsch
- Department of Neurology, The George Washington University School of Medicine and Health Sciences, Washington, DC, United States
| | - Mathieu Beraneck
- Université de Paris, Integrative Neuroscience and Cognition Center, CNRS UMR 8002, Paris, France
| | - Anastas Popratiloff
- The George Washington University Nanofabrication and Imaging Center, Washington, DC, United States
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Yoshimura H, Nishio S, Usami S. Milestones toward cochlear gene therapy for patients with hereditary hearing loss. Laryngoscope Investig Otolaryngol 2021; 6:958-967. [PMID: 34693000 PMCID: PMC8513455 DOI: 10.1002/lio2.633] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/30/2021] [Accepted: 07/28/2021] [Indexed: 02/05/2023] Open
Abstract
A number of genes are reportedly responsible for hereditary hearing loss, which accounts for over 50% of all congenital hearing loss cases. Recent advances in genetic testing have enabled the identification of pathogenic variants in many cases, and systems have been developed to provide personalized treatment based on etiology. Gene therapy is expected to become an unprecedented curative treatment. Several reports have demonstrated the successful use of cochlear gene therapy to restore auditory function in mouse models of genetic deafness; however, many hurdles remain to its clinical application in humans. Herein, we focus on the frequency of deafness genes in patients with congenital and late-onset progressive hearing loss and discuss the following points regarding which genes need to be targeted to efficiently proceed with clinical application: (a) which cells' genes are expressed within the cochlea, (b) whether gene transfer to the targeted cells is possible using vectors such as adeno-associated virus, (c) what phenotype of hearing loss in patients is exhibited, and (d) whether mouse models exist to verify the effectiveness of treatment. Moreover, at the start of clinical application, gene therapy in combination with cochlear implantation may be useful for cases of progressive hearing loss.
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Affiliation(s)
- Hidekane Yoshimura
- Department of OtorhinolaryngologyShinshu University School of MedicineMatsumotoNaganoJapan
| | - Shin‐Ya Nishio
- Department of Hearing Implant SciencesShinshu University School of MedicineMatsumotoNaganoJapan
| | - Shin‐Ichi Usami
- Department of Hearing Implant SciencesShinshu University School of MedicineMatsumotoNaganoJapan
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Mackowetzky K, Yoon KH, Mackowetzky EJ, Waskiewicz AJ. Development and evolution of the vestibular apparatuses of the inner ear. J Anat 2021; 239:801-828. [PMID: 34047378 PMCID: PMC8450482 DOI: 10.1111/joa.13459] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/07/2021] [Accepted: 05/06/2021] [Indexed: 12/16/2022] Open
Abstract
The vertebrate inner ear is a labyrinthine sensory organ responsible for perceiving sound and body motion. While a great deal of research has been invested in understanding the auditory system, a growing body of work has begun to delineate the complex developmental program behind the apparatuses of the inner ear involved with vestibular function. These animal studies have helped identify genes involved in inner ear development and model syndromes known to include vestibular dysfunction, paving the way for generating treatments for people suffering from these disorders. This review will provide an overview of known inner ear anatomy and function and summarize the exciting discoveries behind inner ear development and the evolution of its vestibular apparatuses.
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Affiliation(s)
- Kacey Mackowetzky
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | - Kevin H. Yoon
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | | | - Andrew J. Waskiewicz
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
- Women & Children’s Health Research InstituteUniversity of AlbertaEdmontonAlbertaCanada
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Abstract
Mutations of coding regions and splice sites of SLC26A4 cause Pendred syndrome and nonsyndromic recessive hearing loss DFNB4. SLC26A4 encodes pendrin, a transmembrane exchanger of anions and bases. The mutant SLC26A4 phenotype is characterized by inner ear malformations, including an enlarged vestibular aqueduct (EVA), incomplete cochlear partition type II and modiolar hypoplasia, progressive and fluctuating hearing loss, and vestibular dysfunction. A thyroid iodine organification defect can lead to multinodular goiter and distinguishes Pendred syndrome from DFNB4. Pendred syndrome and DFNB4 are each inherited as an autosomal recessive trait caused by biallelic mutations of SLC26A4 (M2). However, there are some EVA patients with only one detectable mutant allele (M1) of SLC26A4. In most European-Caucasian M1 patients, there is a haplotype that consists of 12 variants upstream of SLC26A4, called CEVA (Caucasian EVA), which acts as a pathogenic recessive allele in trans to mutations affecting the coding regions or splice sites of SLC26A4. This combination of an M1 genotype with the CEVA haplotype is associated with a less severe phenotype than the M2 genotype. The phenotype in EVA patients with no mutant alleles of SLC26A4 (M0) has a very low recurrence probability and is likely to be caused by other factors.
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Affiliation(s)
- Keiji Honda
- Department of Otorhinolaryngology, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Andrew J Griffith
- Department of Otolaryngology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA.
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Tian C, Johnson KR, Lett JM, Voss R, Salt AN, Hartsock JJ, Steyger PS, Ohlemiller KK. CACHD1-deficient mice exhibit hearing and balance deficits associated with a disruption of calcium homeostasis in the inner ear. Hear Res 2021; 409:108327. [PMID: 34388681 DOI: 10.1016/j.heares.2021.108327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/15/2021] [Accepted: 07/27/2021] [Indexed: 11/25/2022]
Abstract
CACHD1 recently was shown to be an α2δ-like subunit that can modulate the activity of some types of voltage-gated calcium channels, including the low-voltage activated, T-type CaV3 channels. CACHD1 is widely expressed in the central nervous system but its biological functions and relationship to disease states are unknown. Here, we report that mice with deleterious Cachd1 mutations are hearing impaired and have balance defects, demonstrating that CACHD1 is functionally important in the peripheral auditory and vestibular organs of the inner ear. The vestibular dysfunction of Cachd1 mutant mice, exhibited by leaning and head tilting behaviors, is related to a deficiency of calcium carbonate crystals (otoconia) in the saccule and utricle. The auditory dysfunction, shown by ABR threshold elevations and reduced DPOAEs, is associated with reduced endocochlear potentials and increased endolymph calcium concentrations. Paint-fills of mutant inner ears from prenatal and newborn mice revealed dilation of the membranous labyrinth caused by an enlarged volume of endolymph. These pathologies all can be related to a disturbance of calcium homeostasis in the endolymph of the inner ear, presumably caused by the loss of CACHD1 regulatory effects on voltage-gated calcium channel activity. Cachd1 expression in the cochlea appears stronger in late embryonic stages than in adults, suggesting an early role in establishing endolymph calcium concentrations. Our findings provide new insights into CACHD1 function and suggest the involvement of voltage-gated calcium channels in endolymph homeostasis, essential for normal auditory and vestibular function.
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Affiliation(s)
- Cong Tian
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA; Department of Biomedical Sciences, School of Medicine, Creighton University, 2500 California Plaza, Omaha, NE, 68178, USA
| | | | - Jaclynn M Lett
- Department of Otolaryngology, Central Institute for the Deaf, Fay and Carl Simons Center for Hearing and Deafness, Washington University School of Medicine, 660 S. Euclid, Saint Louis MO, 63110, USA
| | - Robert Voss
- Department of Otolaryngology, Central Institute for the Deaf, Fay and Carl Simons Center for Hearing and Deafness, Washington University School of Medicine, 660 S. Euclid, Saint Louis MO, 63110, USA
| | - Alec N Salt
- Department of Otolaryngology, Central Institute for the Deaf, Fay and Carl Simons Center for Hearing and Deafness, Washington University School of Medicine, 660 S. Euclid, Saint Louis MO, 63110, USA
| | - Jared J Hartsock
- Department of Otolaryngology, Central Institute for the Deaf, Fay and Carl Simons Center for Hearing and Deafness, Washington University School of Medicine, 660 S. Euclid, Saint Louis MO, 63110, USA
| | - Peter S Steyger
- Department of Biomedical Sciences, School of Medicine, Creighton University, 2500 California Plaza, Omaha, NE, 68178, USA
| | - Kevin K Ohlemiller
- Department of Otolaryngology, Central Institute for the Deaf, Fay and Carl Simons Center for Hearing and Deafness, Washington University School of Medicine, 660 S. Euclid, Saint Louis MO, 63110, USA
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Abstract
Congenital hearing loss is the most common birth defect, estimated to affect 2-3 in every 1000 births. Currently there is no cure for hearing loss. Treatment options are limited to hearing aids for mild and moderate cases, and cochlear implants for severe and profound hearing loss. Here we provide a literature overview of the environmental and genetic causes of congenital hearing loss, common animal models and methods used for hearing research, as well as recent advances towards developing therapies to treat congenital deafness. © 2021 The Authors.
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Affiliation(s)
- Justine M Renauld
- Department of Otolaryngology, Head & Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Martin L Basch
- Department of Otolaryngology, Head & Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, Ohio.,Department of Genetics and Genome Sciences, Case Western Reserve School of Medicine, Cleveland, Ohio.,Department of Biology, Case Western Reserve University, Cleveland, Ohio.,Department of Otolaryngology, Head & Neck Surgery, University Hospitals, Cleveland, Ohio
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Abstract
PURPOSE Congenital primary hypothyroidism (CH) is a state of inadequate thyroid hormone production detected at birth, caused either by absent, underdeveloped or ectopic thyroid gland (dysgenesis), or by defected thyroid hormone biosynthesis (dyshormonogenesis). A genetic component has been identified in many cases of CH. This review summarizes the clinical and biochemical features of the genetic causes of primary CH. METHODS A literature review was conducted of gene defects causing congenital hypothyroidism. RESULTS Mutations in five genes have predominantly been implicated in thyroid dysgenesis (TSHR, FOXE1, NKX2-1, PAX8, and NKX2-5), the primary cause of CH (85%), and mutations in seven genes in thyroid dyshormonogenesis (SLC5A5, TPO, DUOX2, DUOXA2, SLC6A4, Tg, and DEHAL1). These genes encode for proteins that regulate genes expressed during the differentiation of the thyroid, such as TPO and Tg genes, or genes that regulate iodide organification, thyroglobulin synthesis, iodide transport, and iodotyrosine deiodination. Besides thyroid dysgenesis and dyshormonogenesis, additional causes of congenital hypothyroidism, such as iodothyronine transporter defects and resistance to thyroid hormones, have also been associated with genetic mutations. CONCLUSION The identification of the underlying genetic defects of CH is important for genetic counseling of families with an affected member, for identifying additional clinical characteristics or the risk for thyroid neoplasia and for diagnostic and management purposes.
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Affiliation(s)
- Eirini Kostopoulou
- Division of Paediatric Endocrinology and Diabetes, Department of Paediatrics|, University of Patras School of Medicine, Patras, Greece.
| | - Konstantinos Miliordos
- Division of Paediatric Endocrinology and Diabetes, Department of Paediatrics|, University of Patras School of Medicine, Patras, Greece
| | - Bessie Spiliotis
- Division of Paediatric Endocrinology and Diabetes, Department of Paediatrics|, University of Patras School of Medicine, Patras, Greece
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Mohri H, Ninoyu Y, Sakaguchi H, Hirano S, Saito N, Ueyama T. Nox3-Derived Superoxide in Cochleae Induces Sensorineural Hearing Loss. J Neurosci 2021; 41:4716-4731. [PMID: 33849947 PMCID: PMC8260246 DOI: 10.1523/jneurosci.2672-20.2021] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 01/02/2023] Open
Abstract
Reactive oxygen species (ROS) produced by NADPH oxidases (Nox) contribute to the development of different types of sensorineural hearing loss (SNHL), a common impairment in humans with no established treatment. Although the essential role of Nox3 in otoconia biosynthesis and its possible involvement in hearing have been reported in rodents, immunohistological methods targeted at detecting Nox3 expression in inner ear cells reveal ambiguous results. Therefore, the mechanism underlying Nox3-dependent SNHL remains unclear and warrants further investigation. We generated Nox3-Cre knock-in mice, in which Nox3 was replaced with Cre recombinase (Cre). Using Nox3-Cre;tdTomato mice of either sex, in which tdTomato is expressed under the control of the Nox3 promoter, we determined Nox3-expressing regions and cell types in the inner ear. Nox3-expressing cells in the cochlea included various types of supporting cells, outer hair cells, inner hair cells, and spiral ganglion neurons. Nox3 expression increased with cisplatin, age, and noise insults. Moreover, increased Nox3 expression in supporting cells and outer hair cells, especially at the basal turn of the cochlea, played essential roles in ROS-related SNHL. The extent of Nox3 involvement in SNHL follows the following order: cisplatin-induced hearing loss > age-related hearing loss > noise-induced hearing loss. Here, on the basis of Nox3-Cre;tdTomato, which can be used as a reporter system (Nox3-Cre+/-;tdTomato+/+ and Nox3-Cre+/+;tdTomato+/+), and Nox3-KO (Nox3-Cre+/+;tdTomato+/+) mice, we demonstrate that Nox3 inhibition in the cochlea is a promising strategy for ROS-related SNHL, such as cisplatin-induced HL, age-related HL, and noise-induced HL.SIGNIFICANCE STATEMENT We found Nox3-expressing regions and cell types in the inner ear, especially in the cochlea, using Nox3-Cre;tdTomato mice, a reporter system generated in this study. Nox3 expression increased with cisplatin, age, and noise insults in specific cell types in the cochlea and resulted in the loss (apoptosis) of outer hair cells. Thus, Nox3 might serve as a molecular target for the development of therapeutics for sensorineural hearing loss, particularly cisplatin-induced, age-related, and noise-induced hearing loss.
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Affiliation(s)
- Hiroaki Mohri
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Yuzuru Ninoyu
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan
| | - Hirofumi Sakaguchi
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Shigeru Hirano
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Naoaki Saito
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan
| | - Takehiko Ueyama
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan
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Xue W, Tian Y, Xiong Y, Liu F, Feng Y, Chen Z, Yu D, Yin S. Transcriptomic Analysis Reveals an Altered Hcy Metabolism in the Stria Vascularis of the Pendred Syndrome Mouse Model. Neural Plast 2021; 2021:5585394. [PMID: 33959158 DOI: 10.1155/2021/5585394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/19/2021] [Accepted: 04/01/2021] [Indexed: 12/13/2022] Open
Abstract
Purpose Slc26a4-/- mice exhibit severer defects in the development of the cochlea and develop deafness, while the underlying mechanisms responsible for these effects remain unclear. Our study was to investigate the potential mechanism linking SLC26A4 deficiency to hearing loss. Materials and Methods RNA sequencing was applied to analyze the differential gene expression of the stria vascularis (SV) from wildtype and Slc26a4-/- mice. GO and KEGG pathway analysis were performed. Quantitative RT-PCR was applied to validate the expression of candidate genes affected by Slc26a4. ELISA and immunofluorescence technique were used to detect the homocysteine (Hcy) level in serum, brain, and SV, respectively. Results 183 upregulated genes and 63 downregulated genes were identified in the SV associated with Slc26a4 depletion. Transcriptomic profiling revealed that Slc26a4 deficiency significantly affected the expression of genes associated with cell adhesion, transmembrane transport, and the biogenesis of multicellular organisms. The SV from Slc26a4-/- mice exhibited a higher expression of Bhmt mRNAs, as well as altered homocysteine (Hcy) metabolism. Conclusions The altered expression of Bhmt results in a dramatic change in multiple biochemical reactions and a disruption of nutrient homeostasis in the endolymph which may contribute to hearing loss of Slc26a4 knockout mouse.
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Abstract
The differential diagnosis of vertigo syndromes is a challenging issue, as many - and in particular - rare disorders of the vestibular labyrinth can hide behind the very common symptoms of "vertigo" and "dizziness". The following article presents an overview of those rare disorders of the balance organ that are of special interest for the otorhinolaryngologist dealing with vertigo disorders. For a better orientation, these disorders are categorized as acute (AVS), episodic (EVS) and chronic vestibular syndromes (CVS) according to their clinical presentation. The main focus lies on EVS sorted by their duration and the presence/absence of triggering factors (seconds, no triggers: vestibular paroxysmia, Tumarkin attacks; seconds, sound and pressure induced: "third window" syndromes; seconds to minutes, positional: rare variants and differential diagnoses of benign paroxysmal positional vertigo; hours to days, spontaneous: intralabyrinthine schwannomas, endolymphatic sac tumors, autoimmune disorders of the inner ear). Furthermore, rare causes of AVS (inferior vestibular neuritis, otolith organ specific dysfunction, vascular labyrinthine disorders, acute bilateral vestibulopathy) and CVS (chronic bilateral vestibulopathy) are covered. In each case, special emphasis is laid on the decisive diagnostic test for the identification of the rare disease and "red flags" for potentially dangerous disorders (e. g. labyrinthine infarction/hemorrhage). Thus, this chapter may serve as a clinical companion for the otorhinolaryngologist aiding in the efficient diagnosis and treatment of rare disorders of the vestibular labyrinth.
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Affiliation(s)
- Julia Dlugaiczyk
- Klinik für Ohren-, Nasen-, Hals- und Gesichtschirurgie
& Interdisziplinäres Zentrum für Schwindel und
neurologische Sehstörungen, Universitätsspital Zürich
(USZ), Universität Zürich (UZH), Zürich,
Schweiz
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43
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Hu CJ, Lu YC, Yang TH, Chan YH, Tsai CY, Yu IS, Lin SW, Liu TC, Cheng YF, Wu CC, Hsu CJ. Toward the Pathogenicity of the SLC26A4 p.C565Y Variant Using a Genetically Driven Mouse Model. Int J Mol Sci 2021; 22:2789. [PMID: 33801843 PMCID: PMC8001573 DOI: 10.3390/ijms22062789] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 02/01/2021] [Revised: 03/05/2021] [Accepted: 03/05/2021] [Indexed: 11/19/2022] Open
Abstract
Recessive variants of the SLC26A4 gene are globally a common cause of hearing impairment. In the past, cell lines and transgenic mice were widely used to investigate the pathogenicity associated with SLC26A4 variants. However, discrepancies in pathogenicity between humans and cell lines or transgenic mice were documented for some SLC26A4 variants. For instance, the p.C565Y variant, which was reported to be pathogenic in humans, did not exhibit functional pathogenic consequences in cell lines. To address the pathogenicity of p.C565Y, we used a genotype-based approach in which we generated knock-in mice that were heterozygous (Slc26a4+/C565Y), homozygous (Slc26a4C565Y/C565Y), and compound heterozygous (Slc26a4919-2A>G/C565Y) for this variant. Subsequent phenotypic characterization revealed that mice with these genotypes demonstrated normal auditory and vestibular functions, and normal inner-ear morphology and pendrin expression. These findings indicate that the p.C565Y variant is nonpathogenic for mice, and that a single p.C565Y allele is sufficient to maintain normal inner-ear physiology in mice. Our results highlight the differences in pathogenicity associated with certain SLC26A4 variants between transgenic mice and humans, which should be considered when interpreting the results of animal studies for SLC26A4-related deafness.
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Affiliation(s)
- Chin-Ju Hu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA 02115, USA
| | - Ying-Chang Lu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Department of Medical Research, Taipei Veteran General Hospital, Taipei 112, Taiwan
| | - Ting-Hua Yang
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
| | - Yen-Hui Chan
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung 427, Taiwan
| | - Cheng-Yu Tsai
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
| | - I-Shing Yu
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center for Medical Excellence, National Taiwan University, Taipei 100, Taiwan; (I-S.Y.); (S.-W.L.)
| | - Shu-Wha Lin
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center for Medical Excellence, National Taiwan University, Taipei 100, Taiwan; (I-S.Y.); (S.-W.L.)
| | - Tien-Chen Liu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
| | - Yen-Fu Cheng
- Department of Medical Research, Taipei Veteran General Hospital, Taipei 112, Taiwan
- Department of Otolaryngology-Head and Neck Surgery, Taipei Veteran General Hospital, Taipei 112, Taiwan
- Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Chen-Chi Wu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Department of Medical Genetics, National Taiwan University Hospital, Taipei 100, Taiwan
- Department of Otolaryngology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Chuan-Jen Hsu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung 427, Taiwan
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Berg P, Svendsen SL, Hoang TTL, Praetorius HA, Sorensen MV, Leipziger J. Impaired renal HCO 3 - secretion in CFTR deficient mice causes metabolic alkalosis during chronic base-loading. Acta Physiol (Oxf) 2021; 231:e13591. [PMID: 33270356 DOI: 10.1111/apha.13591] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [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: 04/23/2020] [Revised: 11/27/2020] [Accepted: 11/27/2020] [Indexed: 12/11/2022]
Abstract
AIM Cystic fibrosis patients have an increased risk of developing metabolic alkalosis presumably as a result of altered renal HCO3 - handling. In this study, we directly assess the kidneys' ability to compensate for a chronic base-load in the absence of functional CFTR. METHODS Comprehensive urine and blood acid-base analyses were done in anaesthetized WT mice or mice lacking either CFTR or pendrin, with or without 7 days of oral NaHCO3 loading. The in vivo experiments were complemented by a combination of immunoblotting and experiments with perfused isolated mouse cortical collecting ducts (CCD). RESULTS Base-loaded WT mice maintained acid-base homeostasis by elevating urinary pH and HCO3 - excretion and decreasing urinary net acid excretion. In contrast, pendrin KO mice and CFTR KO mice were unable to increase urinary pH and HCO3 - excretion and unable to decrease urinary net acid excretion sufficiently and thus developed metabolic alkalosis in response to the same base-load. The expression of pendrin was increased in response to the base-load in WT mice with a paralleled increased pendrin function in the perfused CCD. In CFTR KO mice, 7 days of base-loading did not upregulate pendrin expression and apical Cl- /HCO3 - exchange function was strongly blunted in the CCD. CONCLUSION CFTR KO mice develop metabolic alkalosis during a chronic base-load because they are unable to sufficiently elevate renal HCO3 - excretion. This can be explained by markedly reduced pendrin function in the absence of CFTR.
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Affiliation(s)
- Peder Berg
- Department of Biomedicine, Physiology Faculty of Health Aarhus University Aarhus C Denmark
| | - Samuel L. Svendsen
- Department of Biomedicine, Physiology Faculty of Health Aarhus University Aarhus C Denmark
| | - Thi Thuy Linh Hoang
- Department of Biomedicine, Physiology Faculty of Health Aarhus University Aarhus C Denmark
| | - Helle A. Praetorius
- Department of Biomedicine, Physiology Faculty of Health Aarhus University Aarhus C Denmark
| | - Mads V. Sorensen
- Department of Biomedicine, Physiology Faculty of Health Aarhus University Aarhus C Denmark
| | - Jens Leipziger
- Department of Biomedicine, Physiology Faculty of Health Aarhus University Aarhus C Denmark
- Aarhus Institute of Advanced Studies Aarhus University Aarhus C Denmark
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Simon F, Denoyelle F, Beraneck M. Interpreting pendred syndrome as a foetal hydrops: Clinical and animal model evidence. J Vestib Res 2021; 31:315-321. [PMID: 33579884 DOI: 10.3233/ves-200789] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Menière disease (MD) and SLC26A4 related deafness (Pendred syndrome (PS) or DFNB4) are two different inner ear disorders which present with fluctuating and progressive hearing loss, which could be a direct consequence of endolymphatic hydrops. OBJECTIVE To present similarities between both pathologies and explore how the concept of hydrops may be applied to PS/DFNB4. METHODS Review of the literature on MD, PS/DFNB4 and mouse model of PS/DFNB4. RESULTS MD and PS/DFNB4 share a number of similarities such as fluctuating and progressive hearing loss, acute episodes with vertigo and tinnitus, MRI and histological evidence of endolymphatic hydrops (although with different underlying mechanisms). MD is usually diagnosed during the fourth decade of life whereas PS/DFNB4 is congenital. The PS/DFNB4 mouse models have shown that biallelic slc26a4 mutations lead to Na+ and water retention in the endolymph during the perinatal period, which in turn induces degeneration of the stria vascularis and hearing loss. Crossing clinical/imagery characteristics and animal models, evidence seems to support the hypothesis of PS being a foetal hydrops. CONCLUSIONS When understanding PS/DFNB4 as a developmental hydrops, treatments used in MD could be repositioned to PS.
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Affiliation(s)
- François Simon
- Université de Paris, INCC UMR 8002, CNRS, F-75006 Paris, France.,Université de Paris, Faculté de Médecine, F-75006 Paris, France.,Department of Paediatric Otolaryngology, AP-HP, Hôpital Necker-Enfants Malades, F-75015 Paris, France
| | - Françoise Denoyelle
- Université de Paris, Faculté de Médecine, F-75006 Paris, France.,Department of Paediatric Otolaryngology, AP-HP, Hôpital Necker-Enfants Malades, F-75015 Paris, France
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46
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Gu X, Jiang Q, Sun W, Guo W, Yang S. Anatomical analysis of vestibular aqueducts in humans and miniature pigs. Anat Rec (Hoboken) 2021. [DOI: 10.1002/ar.24577] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Xiang Gu
- College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital Beijing China
- Department of Otolayngology, Head & Neck Surgery, The Tianjin Children's Hospital Tianjin P.R. China
- State Key Lab of Hearing Science Ministry of Education Beijing China
- Department of Otolaryngeal‐Head Neck Surgery, Chinese PLA General Hospital Beijing P.R. China
- Chinese PLA Medical School Beijing China
| | - Qing‐qing Jiang
- College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital Beijing China
- Department of Otolayngology, Head & Neck Surgery, The Tianjin Children's Hospital Tianjin P.R. China
- State Key Lab of Hearing Science Ministry of Education Beijing China
- Department of Otolaryngeal‐Head Neck Surgery, Chinese PLA General Hospital Beijing P.R. China
- Chinese PLA Medical School Beijing China
| | - Wei Sun
- Department of Communicative Disorders & Sciences, Center for Hearing and Deafness State University of New York at Buffalo New York USA
| | - Weiwei Guo
- College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital Beijing China
- Department of Otolayngology, Head & Neck Surgery, The Tianjin Children's Hospital Tianjin P.R. China
- State Key Lab of Hearing Science Ministry of Education Beijing China
- Department of Otolaryngeal‐Head Neck Surgery, Chinese PLA General Hospital Beijing P.R. China
- Chinese PLA Medical School Beijing China
| | - Shi‐Ming Yang
- College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital Beijing China
- Department of Otolayngology, Head & Neck Surgery, The Tianjin Children's Hospital Tianjin P.R. China
- State Key Lab of Hearing Science Ministry of Education Beijing China
- Department of Otolaryngeal‐Head Neck Surgery, Chinese PLA General Hospital Beijing P.R. China
- Chinese PLA Medical School Beijing China
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47
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Han JW, Wang L, Zhao H, Yang SM. Biomechanical analysis of the clinical characteristics of enlarged vestibular aqueduct syndrome with Mondini malformation. Acta Otolaryngol 2020; 140:813-817. [PMID: 32662706 DOI: 10.1080/00016489.2020.1780312] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND numerous researches on the pathological mechanism of Enlarged Vestibular Aqueduct (EVA) syndrome mainly focuses on the genetic characteristics of SLC26A4 gene and the function of its encoding protein, Pendrin. One of the limitations with these explanations is that it does not explain why cerebrospinal fluid pressure can affect clinical manifestations. OBJECTIVES To establish a new approach to explain the clinical manifestations of EVA syndrome with biomechanical method. MATERIAL AND METHODS 108 cases of EVA syndrome who received cochlear implantation were analyzed retrospectively. A cochlear model was built to reflect the differences of the structure in EVA syndrome with or without Mondini malformation. The CFD software was used to simulate and display the differences in mechanical pathogenic factors to which the model was subjected. RESULTS EVA syndrome patients with Mondini malformation suffer more mechanical damage from the cerebrospinal fluid pressure due to their structural reason and their symptoms appear earlier and progress faster. CONCLUSIONS Biomechanics is an important aspect of pathological mechanism of EVA syndrome, and it provides a new angle for clinical decision-making.
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Affiliation(s)
- Jia-Wei Han
- College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Lab of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Lin Wang
- Nursing Department, Hainan Hospital of Chinese PLA General Hospital, Sanya, China
| | - Hui Zhao
- College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Lab of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Shi-Ming Yang
- College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Lab of Hearing Impairment Prevention and Treatment, Beijing, China
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Askew C, Chien WW. Adeno-associated virus gene replacement for recessive inner ear dysfunction: Progress and challenges. Hear Res 2020; 394:107947. [PMID: 32247629 DOI: 10.1016/j.heares.2020.107947] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 03/02/2020] [Accepted: 03/04/2020] [Indexed: 01/08/2023]
Abstract
Approximately 3 in 1000 children in the US under 4 years of age are affected by hearing loss. Currently, cochlear implants represent the only line of treatment for patients with severe to profound hearing loss, and there are no targeted drug or biological based therapies available. Gene replacement is a promising therapeutic approach for hereditary hearing loss, where viral vectors are used to deliver functional cDNA to "replace" defective genes in dysfunctional cells in the inner ear. Proof-of-concept studies have successfully used this approach to improve auditory function in mouse models of hereditary hearing loss, and human clinical trials are on the immediate horizon. The success of this method is ultimately determined by the underlying biology of the defective gene and design of the treatment strategy, relying on intervention before degeneration of the sensory structures occurs. A challenge will be the delivery of a corrective gene to the proper target within the therapeutic window of opportunity, which may be unique for each specific defective gene. Although rescue of pre-lingual forms of recessive deafness have been explored in animal models thus far, future identification of genes with post-lingual onset that are amenable to gene replacement holds even greater promise for treatment, since the therapeutic window is likely open for a much longer period of time. This review summarizes the current state of adeno-associated virus (AAV) gene replacement therapy for recessive hereditary hearing loss and discusses potential challenges and opportunities for translating inner ear gene replacement therapy for patients with hereditary hearing loss.
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Affiliation(s)
- Charles Askew
- Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Wade W Chien
- Inner Ear Gene Therapy Program, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health, Bethesda, MD, USA; Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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Lee EH, Shin MH, Gi M, Park J, Song D, Hyun YM, Ryu JH, Seong JK, Jeon Y, Han G, Namkung W, Park MS, Choi JY. Inhibition of Pendrin by a small molecule reduces Lipopolysaccharide-induced acute Lung Injury. Theranostics 2020; 10:9913-9922. [PMID: 32929324 PMCID: PMC7481407 DOI: 10.7150/thno.46417] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/27/2020] [Indexed: 12/11/2022] Open
Abstract
Rationale: Pendrin is encoded by SLC26A4 and its mutation leads to congenital hearing loss. Additionally, pendrin is up-regulated in inflammatory airway diseases such as chronic obstructive pulmonary disease, allergic rhinitis, and asthma. In this study, the effects of a novel pendrin inhibitor, YS-01, were investigated in an LPS-induced acute lung injury (ALI) mice model, and the mechanism underlying the effect of YS-01 was examined. Methods: Lipopolysaccharide (LPS, 10 mg/kg) was intranasally instilled in wild type (WT) and pendrin-null mice. YS-01 (10 mg/kg) was administered intra-peritoneally before or after LPS inhalation. Lung injury parameters were assessed in the lung tissue and bronchoalveolar lavage fluid (BALF). Pendrin levels in the BALF of 41 patients with acute respiratory distress syndrome (ARDS) due to pneumonia and 25 control (solitary pulmonary nodule) patients were also measured. Results: LPS instillation induced lung injury in WT mice but not in pendrin-null mice. Pendrin expression was increased by LPS stimulation both in vitro and in vivo. YS-01 treatment dramatically attenuated lung injury and reduced BALF cell counts and protein concentration after LPS instillation in WT mice. Proinflammatory cytokines and NF-κB activation were suppressed by YS-01 treatment in LPS-induced ALI mice. In BALF of patients whose ARDS was caused by pneumonia, pendrin expression was up-regulated compared to that in controls (mean, 24.86 vs. 6.83 ng/mL, P < 0.001). Conclusions: A novel pendrin inhibitor, YS-01, suppressed lung injury in LPS-induced ALI mice and our data provide a new strategy for the treatment of inflammatory airway diseases including sepsis-induced ALI.
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Berg P, Svendsen SL, Sorensen MV, Larsen CK, Andersen JF, Jensen-Fangel S, Jeppesen M, Schreiber R, Cabrita I, Kunzelmann K, Leipziger J. Impaired Renal HCO 3 - Excretion in Cystic Fibrosis. J Am Soc Nephrol 2020; 31:1711-1727. [PMID: 32703846 DOI: 10.1681/asn.2020010053] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/13/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Patients with cystic fibrosis (CF) do not respond with increased urinary HCO3 - excretion after stimulation with secretin and often present with metabolic alkalosis. METHODS By combining RT-PCR, immunohistochemistry, isolated tubule perfusion, in vitro cell studies, and in vivo studies in different mouse models, we elucidated the mechanism of secretin-induced urinary HCO3 - excretion. For CF patients and CF mice, we developed a HCO3 - drinking test to assess the role of the cystic fibrosis transmembrane conductance regulator (CFTR) in urinary HCO3 -excretion and applied it in the patients before and after treatment with the novel CFTR modulator drug, lumacaftor-ivacaftor. RESULTS β-Intercalated cells express basolateral secretin receptors and apical CFTR and pendrin. In vivo application of secretin induced a marked urinary alkalization, an effect absent in mice lacking pendrin or CFTR. In perfused cortical collecting ducts, secretin stimulated pendrin-dependent Cl-/HCO3 - exchange. In collecting ducts in CFTR knockout mice, baseline pendrin activity was significantly lower and not responsive to secretin. Notably, patients with CF (F508del/F508del) and CF mice showed a greatly attenuated or absent urinary HCO3 --excreting ability. In patients, treatment with the CFTR modulator drug lumacaftor-ivacaftor increased the renal ability to excrete HCO3 -. CONCLUSIONS These results define the mechanism of secretin-induced urinary HCO3 - excretion, explain metabolic alkalosis in patients with CF, and suggest feasibility of an in vivo human CF urine test to validate drug efficacy.
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Affiliation(s)
- Peder Berg
- Department of Biomedicine, Physiology and Biophysics, Aarhus University, Aarhus, Denmark
| | - Samuel L Svendsen
- Department of Biomedicine, Physiology and Biophysics, Aarhus University, Aarhus, Denmark
| | - Mads V Sorensen
- Department of Biomedicine, Physiology and Biophysics, Aarhus University, Aarhus, Denmark
| | - Casper K Larsen
- Department of Biomedicine, Physiology and Biophysics, Aarhus University, Aarhus, Denmark
| | - Jesper Frank Andersen
- Department of Biomedicine, Physiology and Biophysics, Aarhus University, Aarhus, Denmark
| | - Søren Jensen-Fangel
- Department of Infectious Diseases, Aarhus University Hospital, Aarhus, Denmark
| | - Majbritt Jeppesen
- Department of Infectious Diseases, Aarhus University Hospital, Aarhus, Denmark
| | - Rainer Schreiber
- Department of Physiology, University of Regensburg, Regensburg, Germany
| | - Ines Cabrita
- Department of Physiology, University of Regensburg, Regensburg, Germany
| | - Karl Kunzelmann
- Department of Physiology, University of Regensburg, Regensburg, Germany
| | - Jens Leipziger
- Department of Biomedicine, Physiology and Biophysics, Aarhus University, Aarhus, Denmark
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