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Xie Z, Ma XH, Bai QF, Tang J, Sun JH, Jiang F, Guo W, Wang CM, Yang R, Wen YC, Wang FY, Chen YX, Zhang H, He DZ, Kelley MW, Yang S, Zhang WJ. ZBTB20 is essential for cochlear maturation and hearing in mice. Proc Natl Acad Sci U S A 2023; 120:e2220867120. [PMID: 37279265 PMCID: PMC10268240 DOI: 10.1073/pnas.2220867120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 04/25/2023] [Indexed: 06/08/2023] Open
Abstract
The mammalian cochlear epithelium undergoes substantial remodeling and maturation before the onset of hearing. However, very little is known about the transcriptional network governing cochlear late-stage maturation and particularly the differentiation of its lateral nonsensory region. Here, we establish ZBTB20 as an essential transcription factor required for cochlear terminal differentiation and maturation and hearing. ZBTB20 is abundantly expressed in the developing and mature cochlear nonsensory epithelial cells, with transient expression in immature hair cells and spiral ganglion neurons. Otocyst-specific deletion of Zbtb20 causes profound deafness with reduced endolymph potential in mice. The subtypes of cochlear epithelial cells are normally generated, but their postnatal development is arrested in the absence of ZBTB20, as manifested by an immature appearance of the organ of Corti, malformation of tectorial membrane (TM), a flattened spiral prominence (SP), and a lack of identifiable Boettcher cells. Furthermore, these defects are related with a failure in the terminal differentiation of the nonsensory epithelium covering the outer border Claudius cells, outer sulcus root cells, and SP epithelial cells. Transcriptome analysis shows that ZBTB20 regulates genes encoding for TM proteins in the greater epithelial ridge, and those preferentially expressed in root cells and SP epithelium. Our results point to ZBTB20 as an essential regulator for postnatal cochlear maturation and particularly for the terminal differentiation of cochlear lateral nonsensory domain.
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Affiliation(s)
- Zhifang Xie
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai200092, China
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - Xian-Hua Ma
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - Qiu-Fang Bai
- NHC Key Laboratory of Hormones and Development, Chu Hsien-I Memorial Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin300134, China
| | - Jie Tang
- Department of Physiology, Southern Medical University, Guangzhou, Guangdong510515, China
| | - Jian-He Sun
- Senior Department of Otolaryngology-Head and Neck Surgery, National Clinical Research Center for Otolaryngologic Diseases, the Sixth Medical Center of PLA General Hospital, Beijing100141, China
| | - Fei Jiang
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai200092, China
| | - Wei Guo
- Senior Department of Otolaryngology-Head and Neck Surgery, National Clinical Research Center for Otolaryngologic Diseases, the Sixth Medical Center of PLA General Hospital, Beijing100141, China
| | - Chen-Ma Wang
- NHC Key Laboratory of Hormones and Development, Chu Hsien-I Memorial Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin300134, China
| | - Rui Yang
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - Yin-Chuan Wen
- Department of Physiology, Southern Medical University, Guangzhou, Guangdong510515, China
| | - Fang-Yuan Wang
- Senior Department of Otolaryngology-Head and Neck Surgery, National Clinical Research Center for Otolaryngologic Diseases, the Sixth Medical Center of PLA General Hospital, Beijing100141, China
| | - Yu-Xia Chen
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - Hai Zhang
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - David Z. He
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE68178
| | | | - Shiming Yang
- Senior Department of Otolaryngology-Head and Neck Surgery, National Clinical Research Center for Otolaryngologic Diseases, the Sixth Medical Center of PLA General Hospital, Beijing100141, China
| | - Weiping J. Zhang
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
- NHC Key Laboratory of Hormones and Development, Chu Hsien-I Memorial Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin300134, China
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2
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Wagner CA, Unwin R, Lopez-Garcia SC, Kleta R, Bockenhauer D, Walsh S. The pathophysiology of distal renal tubular acidosis. Nat Rev Nephrol 2023; 19:384-400. [PMID: 37016093 DOI: 10.1038/s41581-023-00699-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2023] [Indexed: 04/06/2023]
Abstract
The kidneys have a central role in the control of acid-base homeostasis owing to bicarbonate reabsorption and production of ammonia and ammonium in the proximal tubule and active acid secretion along the collecting duct. Impaired acid excretion by the collecting duct system causes distal renal tubular acidosis (dRTA), which is characterized by the failure to acidify urine below pH 5.5. This defect originates from reduced function of acid-secretory type A intercalated cells. Inherited forms of dRTA are caused by variants in SLC4A1, ATP6V1B1, ATP6V0A4, FOXI1, WDR72 and probably in other genes that are yet to be discovered. Inheritance of dRTA follows autosomal-dominant and -recessive patterns. Acquired forms of dRTA are caused by various types of autoimmune diseases or adverse effects of some drugs. Incomplete dRTA is frequently found in patients with and without kidney stone disease. These patients fail to appropriately acidify their urine when challenged, suggesting that incomplete dRTA may represent an intermediate state in the spectrum of the ability to excrete acids. Unrecognized or insufficiently treated dRTA can cause rickets and failure to thrive in children, osteomalacia in adults, nephrolithiasis and nephrocalcinosis. Electrolyte disorders are also often present and poorly controlled dRTA can increase the risk of developing chronic kidney disease.
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Affiliation(s)
- Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland.
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK.
| | - Robert Unwin
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
| | - Sergio C Lopez-Garcia
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
- Department of Paediatric Nephrology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Robert Kleta
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
| | - Detlef Bockenhauer
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
- Department of Paediatric Nephrology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Stephen Walsh
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
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3
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Carlos dos Reis D, Dastoor P, Santos AK, Sumigray K, Ameen NA. CFTR high expresser cells in cystic fibrosis and intestinal diseases. Heliyon 2023; 9:e14568. [PMID: 36967909 PMCID: PMC10031467 DOI: 10.1016/j.heliyon.2023.e14568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 03/02/2023] [Accepted: 03/09/2023] [Indexed: 03/16/2023] Open
Abstract
Cystic Fibrosis Transmembrane Conductance Regulator (CFTR), the Cl-/HCO3 - channel implicated in Cystic Fibrosis, is critical to the pathophysiology of many gastrointestinal diseases. Defects in CFTR lead to intestinal dysfunction, malabsorption, obstruction, infection, inflammation, and cancer that increases morbidity and reduces quality of life. This review will focus on CFTR in the intestine and the implications of the subpopulation of CFTR High Expresser Cells (CHEs) in Cystic Fibrosis (CF), intestinal physiology and pathophysiology of intestinal diseases.
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Affiliation(s)
- Diego Carlos dos Reis
- Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, CT, 06510, USA
| | - Parinaz Dastoor
- Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, CT, 06510, USA
| | - Anderson Kenedy Santos
- Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, CT, 06510, USA
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Kaelyn Sumigray
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA
- Yale Stem Cell Center, Yale School of Medicine, New Haven, CT, 06510, USA
- Yale Cancer Center, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Nadia A. Ameen
- Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, CT, 06510, USA
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT06510, USA
- Corresponding author. Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, CT, 06510, USA.
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4
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Szeto IYY, Chu DKH, Chen P, Chu KC, Au TYK, Leung KKH, Huang YH, Wynn SL, Mak ACY, Chan YS, Chan WY, Jauch R, Fritzsch B, Sham MH, Lovell-Badge R, Cheah KSE. SOX9 and SOX10 control fluid homeostasis in the inner ear for hearing through independent and cooperative mechanisms. Proc Natl Acad Sci U S A 2022; 119:e2122121119. [PMID: 36343245 PMCID: PMC9674217 DOI: 10.1073/pnas.2122121119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 09/10/2022] [Indexed: 11/09/2022] Open
Abstract
The in vivo mechanisms underlying dominant syndromes caused by mutations in SRY-Box Transcription Factor 9 (SOX9) and SOX10 (SOXE) transcription factors, when they either are expressed alone or are coexpressed, are ill-defined. We created a mouse model for the campomelic dysplasia SOX9Y440X mutation, which truncates the transactivation domain but leaves DNA binding and dimerization intact. Here, we find that SOX9Y440X causes deafness via distinct mechanisms in the endolymphatic sac (ES)/duct and cochlea. By contrast, conditional heterozygous Sox9-null mice are normal. During the ES development of Sox9Y440X/+ heterozygotes, Sox10 and genes important for ionic homeostasis are down-regulated, and there is developmental persistence of progenitors, resulting in fewer mature cells. Sox10 heterozygous null mutants also display persistence of ES/duct progenitors. By contrast, SOX10 retains its expression in the early Sox9Y440X/+ mutant cochlea. Later, in the postnatal stria vascularis, dominant interference by SOX9Y440X is implicated in impairing the normal cooperation of SOX9 and SOX10 in repressing the expression of the water channel Aquaporin 3, thereby contributing to endolymphatic hydrops. Our study shows that for a functioning endolymphatic system in the inner ear, SOX9 regulates Sox10, and depending on the cell type and target gene, it works either independently of or cooperatively with SOX10. SOX9Y440X can interfere with the activity of both SOXE factors, exerting effects that can be classified as haploinsufficient/hypomorphic or dominant negative depending on the cell/gene context. This model of disruption of transcription factor partnerships may be applicable to congenital deafness, which affects ∼0.3% of newborns, and other syndromic disorders.
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Affiliation(s)
- Irene Y. Y. Szeto
- School of Biomedical Sciences, The University of Hong Kong, Li Ka Shing Faculty of Medicine, Hong Kong, China
| | - Daniel K. H. Chu
- School of Biomedical Sciences, The University of Hong Kong, Li Ka Shing Faculty of Medicine, Hong Kong, China
| | - Peikai Chen
- School of Biomedical Sciences, The University of Hong Kong, Li Ka Shing Faculty of Medicine, Hong Kong, China
| | - Ka Chi Chu
- School of Biomedical Sciences, The University of Hong Kong, Li Ka Shing Faculty of Medicine, Hong Kong, China
| | - Tiffany Y. K. Au
- School of Biomedical Sciences, The University of Hong Kong, Li Ka Shing Faculty of Medicine, Hong Kong, China
| | - Keith K. H. Leung
- School of Biomedical Sciences, The University of Hong Kong, Li Ka Shing Faculty of Medicine, Hong Kong, China
| | - Yong-Heng Huang
- Genome Regulation Laboratory, CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
- Guangzhou Medical University, Guangzhou 511436, China
| | - Sarah L. Wynn
- School of Biomedical Sciences, The University of Hong Kong, Li Ka Shing Faculty of Medicine, Hong Kong, China
| | - Angel C. Y. Mak
- School of Biomedical Sciences, The University of Hong Kong, Li Ka Shing Faculty of Medicine, Hong Kong, China
| | - Ying-Shing Chan
- School of Biomedical Sciences, The University of Hong Kong, Li Ka Shing Faculty of Medicine, Hong Kong, China
| | - Wood Yee Chan
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Ralf Jauch
- School of Biomedical Sciences, The University of Hong Kong, Li Ka Shing Faculty of Medicine, Hong Kong, China
- Genome Regulation Laboratory, CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
- Guangzhou Medical University, Guangzhou 511436, China
| | - Bernd Fritzsch
- Department of Biology, College of Arts & Sciences, University of Iowa, Iowa City, IA 52242
- Department of Otolaryngology, College of Arts & Sciences, University of Iowa, Iowa City, IA 52242
| | - Mai Har Sham
- School of Biomedical Sciences, The University of Hong Kong, Li Ka Shing Faculty of Medicine, Hong Kong, China
| | | | - Kathryn S. E. Cheah
- School of Biomedical Sciences, The University of Hong Kong, Li Ka Shing Faculty of Medicine, Hong Kong, China
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5
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Shah VS, Chivukula RR, Lin B, Waghray A, Rajagopal J. Cystic Fibrosis and the Cells of the Airway Epithelium: What Are Ionocytes and What Do They Do? ANNUAL REVIEW OF PATHOLOGY 2022; 17:23-46. [PMID: 34437820 PMCID: PMC10837786 DOI: 10.1146/annurev-pathol-042420-094031] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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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6
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Roesch S, Rasp G, Sarikas A, Dossena S. Genetic Determinants of Non-Syndromic Enlarged Vestibular Aqueduct: A Review. Audiol Res 2021; 11:423-442. [PMID: 34562878 PMCID: PMC8482117 DOI: 10.3390/audiolres11030040] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/02/2021] [Accepted: 08/24/2021] [Indexed: 12/13/2022] Open
Abstract
Hearing loss is the most common sensorial deficit in humans and one of the most common birth defects. In developed countries, at least 60% of cases of hearing loss are of genetic origin and may arise from pathogenic sequence alterations in one of more than 300 genes known to be involved in the hearing function. Hearing loss of genetic origin is frequently associated with inner ear malformations; of these, the most commonly detected is the enlarged vestibular aqueduct (EVA). EVA may be associated to other cochleovestibular malformations, such as cochlear incomplete partitions, and can be found in syndromic as well as non-syndromic forms of hearing loss. Genes that have been linked to non-syndromic EVA are SLC26A4, GJB2, FOXI1, KCNJ10, and POU3F4. SLC26A4 and FOXI1 are also involved in determining syndromic forms of hearing loss with EVA, which are Pendred syndrome and distal renal tubular acidosis with deafness, respectively. In Caucasian cohorts, approximately 50% of cases of non-syndromic EVA are linked to SLC26A4 and a large fraction of patients remain undiagnosed, thus providing a strong imperative to further explore the etiology of this condition.
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Affiliation(s)
- Sebastian Roesch
- Department of Otorhinolaryngology, Head and Neck Surgery, Paracelsus Medical University, 5020 Salzburg, Austria; (S.R.); (G.R.)
| | - Gerd Rasp
- Department of Otorhinolaryngology, Head and Neck Surgery, Paracelsus Medical University, 5020 Salzburg, Austria; (S.R.); (G.R.)
| | - Antonio Sarikas
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, 5020 Salzburg, Austria;
| | - Silvia Dossena
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, 5020 Salzburg, Austria;
- Correspondence: ; Tel.: +43-(0)662-2420-80564
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7
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Smits JJ, de Bruijn SE, Lanting CP, Oostrik J, O'Gorman L, Mantere T, Cremers FPM, Roosing S, Yntema HG, de Vrieze E, Derks R, Hoischen A, Pegge SAH, Neveling K, Pennings RJE, Kremer H. Exploring the missing heritability in subjects with hearing loss, enlarged vestibular aqueducts, and a single or no pathogenic SLC26A4 variant. Hum Genet 2021; 141:465-484. [PMID: 34410491 PMCID: PMC9035008 DOI: 10.1007/s00439-021-02336-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 08/09/2021] [Indexed: 12/11/2022]
Abstract
Pathogenic variants in SLC26A4 have been associated with autosomal recessive hearing loss (arHL) and a unilateral or bilateral enlarged vestibular aqueduct (EVA). SLC26A4 is the second most frequently mutated gene in arHL. Despite the strong genotype–phenotype correlation, a significant part of cases remains genetically unresolved. In this study, we investigated a cohort of 28 Dutch index cases diagnosed with HL in combination with an EVA but without (M0) or with a single (M1) pathogenic variant in SLC26A4. To explore the missing heritability, we first determined the presence of the previously described EVA-associated haplotype (Caucasian EVA (CEVA)), characterized by 12 single nucleotide variants located upstream of SLC26A4. We found this haplotype and a delimited V1-CEVA haplotype to be significantly enriched in our M1 patient cohort (10/16 cases). The CEVA haplotype was also present in two M0 cases (2/12). Short- and long-read whole genome sequencing and optical genome mapping could not prioritize any of the variants present within the CEVA haplotype as the likely pathogenic defect. Short-read whole-genome sequencing of the six M1 cases without this haplotype and the two M0/CEVA cases only revealed previously overlooked or misinterpreted splice-altering SLC26A4 variants in two cases, who are now genetically explained. No deep-intronic or structural variants were identified in any of the M1 subjects. With this study, we have provided important insights that will pave the way for elucidating the missing heritability in M0 and M1 SLC26A4 cases. For pinpointing the pathogenic effect of the CEVA haplotype, additional analyses are required addressing defect(s) at the RNA, protein, or epigenetic level.
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Affiliation(s)
- Jeroen J Smits
- Hearing and Genes, Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Suzanne E de Bruijn
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Cornelis P Lanting
- Hearing and Genes, Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jaap Oostrik
- Hearing and Genes, Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Luke O'Gorman
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Tuomo Mantere
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.,Laboratory of Cancer Genetics and Tumor Biology, Cancer and Translational Medicine Research Unit and Biocenter Oulu, University of Oulu, Oulu, Finland
| | | | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Helger G Yntema
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Erik de Vrieze
- Hearing and Genes, Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronny Derks
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Alexander Hoischen
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.,Center for Infectious Diseases (RCI), Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Expertise Center for Immunodeficiency and Autoinflammation and Center for Infectious Disease (RCI), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Sjoert A H Pegge
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kornelia Neveling
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Ronald J E Pennings
- Hearing and Genes, Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hannie Kremer
- Hearing and Genes, Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands. .,Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands. .,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.
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8
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Honda K, Griffith AJ. Genetic architecture and phenotypic landscape of SLC26A4-related hearing loss. Hum Genet 2021; 141:455-464. [PMID: 34345941 DOI: 10.1007/s00439-021-02311-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 06/29/2021] [Indexed: 12/15/2022]
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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9
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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] [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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10
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Li H, Rajan GP, Shaw J, Rohani SA, Ladak HM, Agrawal S, Rask-Andersen H. A Synchrotron and Micro-CT Study of the Human Endolymphatic Duct System: Is Meniere's Disease Caused by an Acute Endolymph Backflow? Front Surg 2021; 8:662530. [PMID: 34136526 PMCID: PMC8200827 DOI: 10.3389/fsurg.2021.662530] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/19/2021] [Indexed: 11/13/2022] Open
Abstract
Background: The etiology of Meniere's disease (MD) and endolymphatic hydrops believed to underlie its symptoms remain unknown. One reason may be the exceptional complexity of the human inner ear, its vulnerability, and surrounding hard bone. The vestibular organ contains an endolymphatic duct system (EDS) bridging the different fluid reservoirs. It may be essential for monitoring hydraulic equilibrium, and a dysregulation may result in distension of the fluid spaces or endolymphatic hydrops. Material and Methods: We studied the EDS using high-resolution synchrotron phase contrast non-invasive imaging (SR-PCI), and micro-computed tomography (micro-CT). Ten fresh human temporal bones underwent SR-PCI. One bone underwent micro-CT after fixation and staining with Lugol's iodine solution (I2KI) to increase tissue resolution. Data were processed using volume-rendering software to create 3D reconstructions allowing orthogonal sectioning, cropping, and tissue segmentation. Results: Combined imaging techniques with segmentation and tissue modeling demonstrated the 3D anatomy of the human saccule, utricle, endolymphatic duct, and sac together with connecting pathways. The utricular duct (UD) and utriculo-endolymphatic valve (UEV or Bast's valve) were demonstrated three-dimensionally for the first time. The reunion duct was displayed with micro-CT. It may serve as a safety valve to maintain cochlear endolymph homeostasis under certain conditions. Discussion: The thin reunion duct seems to play a minor role in the exchange of endolymph between the cochlea and vestibule under normal conditions. The saccule wall appears highly flexible, which may explain occult hydrops occasionally preceding symptoms in MD on magnetic resonance imaging (MRI). The design of the UEV and connecting ducts suggests that there is a reciprocal exchange of fluid among the utricle, semicircular canals, and the EDS. Based on the anatomic framework and previous experimental data, we speculate that precipitous vestibular symptoms in MD arise from a sudden increase in endolymph pressure caused by an uncontrolled endolymphatic sac secretion. A rapid rise in UD pressure, mediated along the fairly wide UEV, may underlie the acute vertigo attack, refuting the rupture/K+-intoxication theory.
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Affiliation(s)
- Hao Li
- Department of Surgical Sciences, Section of Otolaryngology and Head and Neck Surgery, Uppsala University Hospital, Uppsala, Sweden
| | - Gunesh P. Rajan
- Department of Otolaryngology, Head and Neck Surgery, Luzerner Kantonsspital, Lucerne, Switzerland
- Department of Otolaryngology, Head and Neck Surgery Division of Surgery, Medical School, University of Western Australia, Perth, WA, Australia
| | - Jeremy Shaw
- Centre for Microscopy, Characterisation and Analysis, Perth, WA, Australia
| | - Seyed Alireza Rohani
- Department of Otolaryngology-Head and Neck Surgery, Western University, London, ON, Canada
| | - Hanif M. Ladak
- Department of Medical Biophysics and Department of Electrical and Computer Engineering, Western University, London, ON, Canada
| | - Sumit Agrawal
- Department of Otolaryngology-Head and Neck Surgery, Western University, London, ON, Canada
| | - Helge Rask-Andersen
- Department of Surgical Sciences, Section of Otolaryngology and Head and Neck Surgery, Uppsala University Hospital, Uppsala, Sweden
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11
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Absence of Endolymphatic Sac Ion Transport Proteins in Large Vestibular Aqueduct Syndrome-A Human Temporal Bone Study. Otol Neurotol 2021; 41:e1256-e1263. [PMID: 32890293 DOI: 10.1097/mao.0000000000002832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Epithelial ion transport pathologies of the endolymphatic sac (ES) are associated with large vestibular aqueduct syndrome (LVAS). BACKGROUND LVAS is defined by the pathognomonic features of a widened bony vestibular aqueduct (VA) and an enlarged ES. The underlying cause of its associated cochleovestibular symptoms remains elusive. Disturbances in epithelial ion transport in the enlarged ES, affecting inner ear fluid regulation, were proposed as a possible pathophysiology. However, although respective epithelial ion transport pathologies have been demonstrated in the enlarged ES from transgenic LVAS mouse models, these pathologies have not been investigated in human LVAS cases. METHODS Histological and immunohistochemical analysis of the enlarged ES epithelium in postmortem temporal bones from two individuals with a clinical diagnosis of LVAS. RESULTS The enlarged ES epithelium demonstrated an overall atypical epithelial differentiation and a lack of the immunolocalization of signature ion transport proteins. Notably, in both cases, a rudimentary branch of the ES with a typically differentiated ES epithelium was present. CONCLUSIONS The described cellular and molecular pathologies of the enlarged ES in humans provide evidence of epithelial transport pathology as one potential cause of cochleovestibular symptoms in LVAS. The present findings also emphasize the clinical relevance of already established LVAS mouse models.
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12
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Eaton AF, Merkulova M, Brown D. The H +-ATPase (V-ATPase): from proton pump to signaling complex in health and disease. Am J Physiol Cell Physiol 2020; 320:C392-C414. [PMID: 33326313 PMCID: PMC8294626 DOI: 10.1152/ajpcell.00442.2020] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A primary function of the H+-ATPase (or V-ATPase) is to create an electrochemical proton gradient across eukaryotic cell membranes, which energizes fundamental cellular processes. Its activity allows for the acidification of intracellular vesicles and organelles, which is necessary for many essential cell biological events to occur. In addition, many specialized cell types in various organ systems such as the kidney, bone, male reproductive tract, inner ear, olfactory mucosa, and more, use plasma membrane V-ATPases to perform specific activities that depend on extracellular acidification. It is, however, increasingly apparent that V-ATPases are central players in many normal and pathophysiological processes that directly influence human health in many different and sometimes unexpected ways. These include cancer, neurodegenerative diseases, diabetes, and sensory perception, as well as energy and nutrient-sensing functions within cells. This review first covers the well-established role of the V-ATPase as a transmembrane proton pump in the plasma membrane and intracellular vesicles and outlines factors contributing to its physiological regulation in different cell types. This is followed by a discussion of the more recently emerging unconventional roles for the V-ATPase, such as its role as a protein interaction hub involved in cell signaling, and the (patho)physiological implications of these interactions. Finally, the central importance of endosomal acidification and V-ATPase activity on viral infection will be discussed in the context of the current COVID-19 pandemic.
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Affiliation(s)
- Amity F Eaton
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Maria Merkulova
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Dennis Brown
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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13
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Dufek B, Meehan DT, Delimont D, Wilhelm K, Samuelson G, Coenen R, Madison J, Doyle E, Smyth B, Phillips G, Gratton MA, Cosgrove D. RNA-seq analysis of gene expression profiles in isolated stria vascularis from wild-type and Alport mice reveals key pathways underling Alport strial pathogenesis. PLoS One 2020; 15:e0237907. [PMID: 32822386 PMCID: PMC7446819 DOI: 10.1371/journal.pone.0237907] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 08/05/2020] [Indexed: 12/20/2022] Open
Abstract
Previous work demonstrates that the hearing loss in Alport mice is caused by defects in the stria vascularis. As the animals age, progressive thickening of strial capillary basement membranes (SCBMs) occurs associated with elevated levels of extracellular matrix expression and hypoxia-related gene and protein expression. These conditions render the animals susceptible to noise-induced hearing loss. In an effort to develop a more comprehensive understanding of how the underlying mutation in the COL4A3 gene influences homeostasis in the stria vascularis, we performed vascular permeability studies combined with RNA-seq analysis using isolated stria vascularis from 7-week old wild-type and Alport mice on the 129 Sv background. Alport SCBMs were found to be less permeable than wild-type littermates. RNA-seq and bioinformatics analysis revealed 68 genes were induced and 61 genes suppressed in the stria from Alport mice relative to wild-type using a cut-off of 2-fold. These included pathways involving transcription factors associated with the regulation of pro-inflammatory responses as well as cytokines, chemokines, and chemokine receptors that are up- or down-regulated. Canonical pathways included modulation of genes associated with glucose and glucose-1-PO4 degradation, NAD biosynthesis, histidine degradation, calcium signaling, and glutamate receptor signaling (among others). In all, the data point to the Alport stria being in an inflammatory state with disruption in numerous metabolic pathways indicative of metabolic stress, a likely cause for the susceptibility of Alport mice to noise-induced hearing loss under conditions that do not cause permanent hearing loss in age/strain-matched wild-type mice. The work lays the foundation for studies aimed at understanding the nature of strial pathology in Alport mice. The modulation of these genes under conditions of therapeutic intervention may provide important pre-clinical data to justify trials in humans afflicted with the disease.
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Affiliation(s)
- Brianna Dufek
- Boys Town National Research Hospital, Omaha, NE, United States of America
| | - Daniel T. Meehan
- Boys Town National Research Hospital, Omaha, NE, United States of America
| | - Duane Delimont
- Boys Town National Research Hospital, Omaha, NE, United States of America
| | - Kevin Wilhelm
- Boys Town National Research Hospital, Omaha, NE, United States of America
| | - Gina Samuelson
- Boys Town National Research Hospital, Omaha, NE, United States of America
| | - Ross Coenen
- Boys Town National Research Hospital, Omaha, NE, United States of America
| | - Jacob Madison
- Boys Town National Research Hospital, Omaha, NE, United States of America
| | - Edward Doyle
- Department of Otolaryngology, Wake Forest School of Medicine, Washington University, Saint Louis, MO, United States of America
| | - Brendan Smyth
- Department of Otolaryngology, Wake Forest School of Medicine, Washington University, Saint Louis, MO, United States of America
| | - Grady Phillips
- Department of Otolaryngology, Wake Forest School of Medicine, Washington University, Saint Louis, MO, United States of America
| | - Michael Anne Gratton
- Department of Otolaryngology, Wake Forest School of Medicine, Washington University, Saint Louis, MO, United States of America
| | - Dominic Cosgrove
- Boys Town National Research Hospital, Omaha, NE, United States of America
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14
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Tong K, Hu Z. FOXI1 expression in chromophobe renal cell carcinoma and renal oncocytoma: a study of The Cancer Genome Atlas transcriptome-based outlier mining and immunohistochemistry. Virchows Arch 2020; 478:647-658. [PMID: 32812119 DOI: 10.1007/s00428-020-02900-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/19/2020] [Accepted: 08/06/2020] [Indexed: 01/09/2023]
Abstract
FOXI1 is a forkhead family transcription factor that plays a key role in differentiation and functional maintenance for the renal intercalated cell (IC). The diagnostic utility of FOXI1 is rarely studied thus far. Comparative analyses of FOXI1 mRNA expression in normal kidney tissue and different renal neoplasms including chromophobe renal cell carcinoma (chRCC), renal oncocytoma (RO), and other renal cell carcinomas were conducted using transcriptomic data from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus, and single-cell RNA-seq datasets, in combination with integrative analyses using mutant data, karyotype data, and digital slides for cases with anomalous FOXI1 expression in TCGA. Formalin-fixed, paraffin-embedded whole-tissue slides of varied primary renal neoplasms (n = 367) were subjected to FOXI1 staining for validating FOXI1 transcription levels. We confirmed that FOXI1 was significantly upregulated at mRNA levels in ICs, chRCCs, and ROs compared with other renal tubule cell and renal cell carcinoma subtypes. Furthermore, most of the cases with FOXI1 expression outliers were misclassified in the TCGA kidney cancer project. An underlying novel entity with frequent mutations involved in the mTOR pathway was also found. FOXI1 immunoreactivity was consistently noted in ICs of the distal nephron. FOXI1 staining was positive in 85 of 93 chRCCs and 13 of 18 ROs, respectively. FOXI1 staining was not seen in renal neoplasms (n = 254) derived from non-ICs. In conclusion, FOXI1 expression in normal kidney tissue is restricted to ICs. This cell type-specific expression is retained during neoplastic transformation from ICs to chRCCs or ROs. FOXI1 is thereby a potential biomarker of IC-related tumors.
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Affiliation(s)
- Kuo Tong
- Department of Pathology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410078, Hunan, China.,Department of Pathology, The Bishan Hospital of Chongqing, Bishan District, Chongqing, 402760, China.,Department of Pathology, School of Basic Medical Science, Central South University, 172 Tongzi Road, Changsha, 410013, Hunan, China
| | - Zhongliang Hu
- Department of Pathology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410078, Hunan, China. .,Department of Pathology, School of Basic Medical Science, Central South University, 172 Tongzi Road, Changsha, 410013, Hunan, China.
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15
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Genini A, Mohebbi N, Daryadel A, Bettoni C, Wagner CA. Adaptive response of the murine collecting duct to alkali loading. Pflugers Arch 2020; 472:1079-1092. [DOI: 10.1007/s00424-020-02423-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/31/2020] [Accepted: 06/19/2020] [Indexed: 01/14/2023]
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16
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Liu Y, Wen J, Sang S, Mei L, He C, Jiang L, Huang S, Feng Y. Next-generation sequencing-based mutation analysis of genes associated with enlarged vestibular aqueduct in Chinese families. Eur Arch Otorhinolaryngol 2020; 277:3331-3339. [PMID: 32447495 DOI: 10.1007/s00405-020-06050-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 05/11/2020] [Indexed: 12/16/2022]
Abstract
OBJECTIVES The identification of gene mutations enables more appropriate genetic counseling and proper medical management for EVA patients. The purpose of this study was to validate the accuracy and sensitivity of our method for comprehensive mutation detection in EVA, and summarize these data to explore a more accurate and convenient genetic diagnosis method. METHODS A multiplex PCR sequencing panel was designed to capture the exons of three known EVA-associated genes (SLC26A4, KCNJ10, and FOXI1), and NGS was conducted in 17 Chinese families with EVA. RESULTS A total of 16 SLC26A4 variants were found in 21 probands with bilateral EVA, including three novel variants (c.416G>A, c.823G>A and c.1027G>C), which were not reported in the dbSNP, gnomAD database, and ClinVar databases. One patient carried a FOXI1 variant (heterozygous, c.214C>A) and one patient carried a KCNJ10 variant (heterozygous, c.1054C>A), both of which were novel variants. Biallelic potential pathogenic variants were detected in 21/21patient samples, leading to a purported diagnostic rate of 100%. All results were verified by Sanger sequencing. CONCLUSION This result supplemented the mutation spectrum of EVA, and supports that combined multiple PCR-targeted enrichment, and NGS is a valuable molecular diagnostic tool for EVA, and is suitable for clinical application.
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Affiliation(s)
- Yalan Liu
- Department of Otolaryngology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China.,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, 410008, Hunan, China
| | - Jie Wen
- Department of Otolaryngology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China.,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, 410008, Hunan, China
| | - Shushan Sang
- Department of Otolaryngology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China.,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, 410008, Hunan, China
| | - Lingyun Mei
- Department of Otolaryngology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China.,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, 410008, Hunan, China
| | - Chufeng He
- Department of Otolaryngology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China.,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, 410008, Hunan, China
| | - Lu Jiang
- Department of Otolaryngology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China.,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, 410008, Hunan, China
| | - Sida Huang
- Department of Otolaryngology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China.,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, 410008, Hunan, China
| | - Yong Feng
- Department of Otolaryngology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China. .,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, 410008, Hunan, China.
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17
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Assmus AM, Mullins JJ, Brown CM, Mullins LJ. Cellular plasticity: A mechanism for homeostasis in the kidney. Acta Physiol (Oxf) 2020; 229:e13447. [PMID: 31991057 DOI: 10.1111/apha.13447] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/15/2020] [Accepted: 01/24/2020] [Indexed: 12/30/2022]
Abstract
Cellular plasticity is a topical subject with interest spanning a wide range of fields from developmental biology to regenerative medicine. Even the nomenclature is a subject of debate, and the underlying mechanisms are still under investigation. On top of injury repair, cell plasticity is a constant physiological process in adult organisms and tissues, in response to homeostatic challenges. In this review we discuss two examples of plasticity for the maintenance of homeostasis in the renal system-namely the renin-producing juxtaglomerular cells (JG cells) and cortical collecting duct (CCD) cells. JG cells show plasticity through recruitment mechanisms, answering the demand for an increase in renin production. In the CCD, cells appear to have the ability to transdifferentiate between principal and intercalated cells to help maintain the highly regulated solute transport levels of that segment. These two cases highlight the complexity of plasticity processes and the role they can play in the kidney.
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Affiliation(s)
- Adrienne M. Assmus
- The University of Edinburgh ‐ Cardiovascular Science (CVS) Queen's Medical Research Institute Edinburgh Scotland UK
| | - John J. Mullins
- The University of Edinburgh ‐ Cardiovascular Science (CVS) Queen's Medical Research Institute Edinburgh Scotland UK
| | - Cara M. Brown
- The University of Edinburgh ‐ Cardiovascular Science (CVS) Queen's Medical Research Institute Edinburgh Scotland UK
| | - Linda J. Mullins
- The University of Edinburgh ‐ Cardiovascular Science (CVS) Queen's Medical Research Institute Edinburgh Scotland UK
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18
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Wang H, Kong X, Pei Y, Cui X, Zhu Y, He Z, Wang Y, Zhang L, Zhuo L, Chen C, Yan X. Mutation spectrum analysis of 29 causative genes in 43 Chinese patients with congenital hypothyroidism. Mol Med Rep 2020; 22:297-309. [PMID: 32319661 PMCID: PMC7248516 DOI: 10.3892/mmr.2020.11078] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 02/13/2020] [Indexed: 12/11/2022] Open
Abstract
Congenital hypothyroidism (CH) is the most common neonatal endocrine disorder with a genetic origin. The purpose of the present study was to analyze the mutation spectrum of CH patients in China. A targeted next-generation sequencing panel covering all exons of 29 CH-related causative genes was used in 43 Han Chinese patients with CH [11 dysgenesis and 32 glands in situ (GIS)]. The functional impact and pathogenicity of detected variants were analyzed using a comprehensive bioinformatics approach and co-segregation studies. A total of 47 rare non-polymorphic variants in 9 target genes associated with thyroid hormone synthesis (DUOX2, DUOXA2, TPO, TG, SLC26A4 and SLC5A5), thyroid stimulating hormone resistance (TSHR) and central hypothyroidism (PROP1 and TRHR) were identified in 31 patients (31/43, 72%). Of these variants, 8 were novel, including 3 in DUOX2, 2 in TPO, 3 in TSHR and 1 in SLC5A5. Variants were mostly affected by DUOX2, TG, TPO and TSHR. Approximately 44% of the patients (19/43) carried DUOX2 variants. The mutation detection rates in patients with GIS were higher compared with patients with dysgenesis [25/32 (78%) vs. 6/11 (54%)]. Oligogenic mutations were detected in 25.6% of the total cases and 35% of the mutated cases. Genetic basis was ascertained in 13 patients, reaching a diagnosis detection rate of 30%. In conclusion, genetic defects in dyshormonogenesis, mainly in DUOX2, were the main genetic cause of CH in the Chinese population. Oligogenicity is highly involved in CH pathogenesis and may thus be an important factor in common phenotypic variability observed in patients with CH.
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Affiliation(s)
- Huijuan Wang
- The National Engineering Research Center for Miniaturized Detection Systems, College of Life Science, Northwest University, Xi'an, Shaanxi 710069, P.R. China
| | - Xiaohong Kong
- The National Engineering Research Center for Miniaturized Detection Systems, College of Life Science, Northwest University, Xi'an, Shaanxi 710069, P.R. China
| | - Yanrui Pei
- The National Engineering Research Center for Miniaturized Detection Systems, College of Life Science, Northwest University, Xi'an, Shaanxi 710069, P.R. China
| | - Xuemei Cui
- The Tianyou Children's Hospital of Xi'an, Xi'an, Shaanxi 710061, P.R. China
| | - Yijie Zhu
- The Chang An Hospital, Xi'an, Shaanxi 710016, P.R. China
| | - Zixuan He
- Beijing Shijitan Hospital, Beijing 100080, P.R. China
| | - Yanxia Wang
- The National Engineering Research Center for Miniaturized Detection Systems, College of Life Science, Northwest University, Xi'an, Shaanxi 710069, P.R. China
| | - Lirong Zhang
- The National Engineering Research Center for Miniaturized Detection Systems, College of Life Science, Northwest University, Xi'an, Shaanxi 710069, P.R. China
| | - Lixia Zhuo
- The National Engineering Research Center for Miniaturized Detection Systems, College of Life Science, Northwest University, Xi'an, Shaanxi 710069, P.R. China
| | - Chao Chen
- The National Engineering Research Center for Miniaturized Detection Systems, College of Life Science, Northwest University, Xi'an, Shaanxi 710069, P.R. China
| | - Xiaoli Yan
- Endocrine Department, Xi'an Children's Hospital, Xi'an, Shaanxi 710003, P.R. China
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19
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Giffen KP, Liu H, Kramer KL, He DZ. Expression of Protein-Coding Gene Orthologs in Zebrafish and Mouse Inner Ear Non-sensory Supporting Cells. Front Neurosci 2019; 13:1117. [PMID: 31680844 PMCID: PMC6813431 DOI: 10.3389/fnins.2019.01117] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/03/2019] [Indexed: 11/13/2022] Open
Abstract
Non-mammalian vertebrates, including zebrafish, retain the ability to regenerate hair cells (HCs) due to unknown molecular mechanisms that regulate proliferation and conversion of non-sensory supporting cells (nsSCs) to HCs. This regenerative capacity is not conserved in mammals. Identification of uniquely expressed orthologous genes in zebrafish nsSCs may reveal gene candidates involved in the proliferation and transdifferentiation of zebrafish nsSCs to HCs in the inner ear. A list of orthologous protein-coding genes was generated based on an Ensembl Biomart comparison of the zebrafish and mouse genomes. Our previously published RNA-seq-based transcriptome datasets of isolated inner ear zebrafish nsSCs and HCs, and mouse non-sensory supporting pillar and Deiters’ cells, and HCs, were merged to analyze gene expression patterns between the two species. Out of 17,498 total orthologs, 11,752 were expressed in zebrafish nsSCs and over 10,000 orthologs were expressed in mouse pillar and Deiters’ cells. Differentially expressed genes common among the zebrafish nsSCs and mouse pillar and Deiters’ cells, compared to species-specific HCs, included 306 downregulated and 314 upregulated genes; however, over 1,500 genes were uniquely upregulated in zebrafish nsSCs. Functional analysis of genes uniquely expressed in nsSCs identified several transcription factors associated with cell fate determination, cell differentiation and nervous system development, indicating inherent molecular properties of nsSCs that promote self-renewal and transdifferentiation into new HCs. Our study provides a means of characterizing these orthologous genes, involved in proliferation and transdifferentiation of nsSCs to HCs in zebrafish, which may lead to identification of potential targets for HC regeneration in mammals.
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Affiliation(s)
- Kimberlee P Giffen
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, United States
| | - Huizhan Liu
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, United States
| | - Kenneth L Kramer
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, United States
| | - David Z He
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, United States
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20
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Molecular basis of hearing loss associated with enlarged vestibular aqueduct. JOURNAL OF BIO-X RESEARCH 2019. [DOI: 10.1097/jbr.0000000000000032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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21
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Immunolocalization of calcium sensing and transport proteins in the murine endolymphatic sac indicates calciostatic functions within the inner ear. Cell Tissue Res 2019; 378:163-173. [PMID: 31338584 PMCID: PMC6815286 DOI: 10.1007/s00441-019-03062-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 06/24/2019] [Indexed: 02/07/2023]
Abstract
An exceptionally low calcium (Ca2+) concentration in the inner ear endolymph ([Ca2+]endolymph) is crucial for proper auditory and vestibular function. The endolymphatic sac (ES) is believed to critically contribute to the maintenance of this low [Ca2+]endolymph. Here, we investigated the immunohistochemical localization of proteins that are presumably involved in the sensing and transport of extracellular Ca2+ in the murine ES epithelium. Light microscopic and fluorescence immunolabeling in paraffin-embedded murine ES tissue sections (male C57BL/6 mice, 6–8 weeks old) demonstrated the presence of the calcium-sensing receptor CaSR, transient receptor potential cation channel subtypes TRPV5 and TRPV6, sarco/endoplasmic reticulum Ca2+-ATPases SERCA1 and SERCA2, Na+/Ca2+ exchanger NCX2, and plasma membrane Ca2+ ATPases PMCA1 and PMCA4 in ES epithelial cells. These proteins exhibited (i) membranous (apical or basolateral) or cytoplasmic localization patterns, (ii) a proximal-to-distal labeling gradient within the ES, and (iii) different distribution patterns among ES epithelial cell types (mitochondria-rich cells (MRCs) and ribosome-rich cells (RRCs)). Notably, in the inner ear membranous labyrinth, CaSR was exclusively localized in MRCs, suggesting a unique role of the ES epithelium in CaSR-mediated sensing and control of [Ca2+]endolymph. Structural loss of the distal ES, which is consistently observed in Meniere’s disease, may therefore critically disturb [Ca2+]endolymph and contribute to the pathogenesis of Meniere’s disease.
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22
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Study on the relationship between the pathogenic mutations of SLC26A4 and CT phenotypes of inner ear in patient with sensorineural hearing loss. Biosci Rep 2019; 39:BSR20182241. [PMID: 30842343 PMCID: PMC6430729 DOI: 10.1042/bsr20182241] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/11/2019] [Accepted: 02/28/2019] [Indexed: 11/23/2022] Open
Abstract
To investigate the possible association of pathogenic mutations of SLC26A4 and computerized tomography (CT) phenotypes of inner ear, and explore the feasibility of using the method of gene sequence analysis. A total of 155 patients with bilateral hearing loss carrying SLC26A4 gene mutations were further subjected to high-resolution temporal bone CT and thyroid B ultrasound tests. The potential relationship between the pathogenic mutations of gene and the CT phenotypes were analyzed. As a result, 65 patients (41.9%, 65/155) carried SLC26A4 gene mutations, and 27 cases were detected with pathogenic mutations of SLC26A4 where IVS7-2A>G (55.6%, 15/27) was the most common pathogenic mutation. Amongst them, 19 patients carrying bi-allelic SLC26A4 mutations were all confirmed to have inner ear malformation by CT scan including four cases of enlarged vestibular aqueduct (EVA) and 15 cases of Mondini dysplasia (MD). However, there was only one in eight cases of single allele pathogenic mutation who was confirmed to have EVA by CT scan. Further, only one patient with EVA was confirmed to be slightly higher of total T3 than normal by thyroid ultrasound scan and thyroid hormone assays. These findings suggested that CT detection and SLC26A4 gene detection are efficient methods to diagnose EVA, which can complement each other. Also, the bi-allelic pathogenic mutations of SLC26A4 are more likely to induce inner ear malformation than single allele pathogenic mutation.
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23
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Hereditary hearing loss; about the known and the unknown. Hear Res 2019; 376:58-68. [PMID: 30665849 DOI: 10.1016/j.heares.2019.01.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/11/2018] [Accepted: 01/07/2019] [Indexed: 01/01/2023]
Abstract
Hereditary hearing loss is both clinically and genetically very heterogeneous. Despite the large number of genes that have been associated with the condition, many cases remain unexplained. Novel gene associations with hearing loss are to be expected but also are defects of regulatory regions of the genome which are currently not routinely addressed in molecular genetic testing and research. Inheritance patterns other than monogenic might be more common than assumed in isolated cases and diagnoses might have been missed because of misinterpretation of identified DNA variants. This review summarizes current insights in the genetics of hearing loss, the next steps that are being taken in research, and their challenges. Furthermore, genotype-phenotype correlations and modifying factors are discussed as these are instrumental in counselling hearing impaired individuals and/or their family members.
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24
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Singh S, Jangid RK, Crowder A, Groves AK. Foxi3 transcription factor activity is mediated by a C-terminal transactivation domain and regulated by the Protein Phosphatase 2A (PP2A) complex. Sci Rep 2018; 8:17249. [PMID: 30467319 PMCID: PMC6250667 DOI: 10.1038/s41598-018-35390-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 11/02/2018] [Indexed: 01/20/2023] Open
Abstract
The Forkhead box (FOX) family consists of at least 19 subgroups of transcription factors which are characterized by the presence of an evolutionary conserved ‘forkhead’ or ‘winged-helix’ DNA-binding domain. Despite having a conserved core DNA binding domain, FOX proteins display remarkable functional diversity and are involved in many developmental and cell specific processes. In the present study, we focus on a poorly characterized member of the Forkhead family, Foxi3, which plays a critical role in the development of the inner ear and jaw. We show that Foxi3 contains at least two important functional domains, a nuclear localization sequence (NLS) and a C-terminal transactivation domain (TAD), and that it directly binds its targets in a sequence specific manner. We also show that the transcriptional activity of Foxi3 is regulated by phosphorylation, and that the activity of Foxi3 can be attenuated by its physical interaction with the protein phosphatase 2A (PP2A) complex.
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Affiliation(s)
- Sunita Singh
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX, 77030, USA
| | - Rahul K Jangid
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX, 77030, USA
| | - Alyssa Crowder
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX, 77030, USA
| | - Andrew K Groves
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX, 77030, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX, 77030, USA. .,Program in Developmental Biology, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX, 77030, USA.
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25
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Targeted Next-Generation Sequencing Facilitates Genetic Diagnosis and Provides Novel Pathogenetic Insights into Deafness with Enlarged Vestibular Aqueduct. J Mol Diagn 2018; 21:138-148. [PMID: 30268946 DOI: 10.1016/j.jmoldx.2018.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 08/13/2018] [Accepted: 08/30/2018] [Indexed: 12/24/2022] Open
Abstract
Enlarged vestibular aqueduct (EVA) is an inner-ear malformation associated with sensorineural hearing impairment. Most EVAs are associated with Pendred syndrome and nonsyndromic autosomal recessive deafness-4 (DFNB4), two autosomal-recessive disorders caused by mutations in SLC26A4. However, many EVA patients cannot have a confirmed diagnosis by screening common SLC26A4 mutations, constituting an enigma in genetic diagnosis. To enable comprehensive genetic examination and explore the etiologies of EVA, we designed a next-generation sequencing panel targeting the entire length of 3 Pendred syndrome/DFNB4 genes (SLC26A4, FOXI1, and KCNJ10) and exons of 10 other genes related to EVA and performed genetic testing in 50 EVA families without confirmative results on screening for SLC26A4 hotspots (c.919-2A>G and p.H723R). Bi-allelic SLC26A4 mutations were identified in 34 families and EYA1 mutations in two families, yielding a diagnostic rate of 72% (36 of 50). In addition, two variants were identified in KCNJ10 and FOXI1, but findings did not support the previous hypothesis that mutations in these two genes are probable contributors to EVA through recessive inheritance or digenic inheritance with SLC26A4. Of note, a large SLC26A4 deletion was confirmed in one step using our panel. These results show the utility of a next-generation sequencing-based panel to address EVA families by identifying various types of gene mutations with satisfactory diagnostic yields and provide novel insights into the pathogenesis of EVA.
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26
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Tian C, Gagnon LH, Longo-Guess C, Korstanje R, Sheehan SM, Ohlemiller KK, Schrader AD, Lett JM, Johnson KR. Hearing loss without overt metabolic acidosis in ATP6V1B1 deficient MRL mice, a new genetic model for non-syndromic deafness with enlarged vestibular aqueducts. Hum Mol Genet 2018; 26:3722-3735. [PMID: 28934385 DOI: 10.1093/hmg/ddx257] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/30/2017] [Indexed: 12/17/2022] Open
Abstract
Mutations of the human ATP6V1B1 gene cause distal renal tubular acidosis (dRTA; OMIM #267300) often associated with sensorineural hearing impairment; however, mice with a knockout mutation of Atp6v1b1 were reported to exhibit a compensated acidosis and normal hearing. We discovered a new spontaneous mutation (vortex, symbol vtx) of Atp6v1b1 in an MRL/MpJ (MRL) colony of mice. In contrast to the reported phenotype of the knockout mouse, which was developed on a primarily C57BL/6 (B6) strain background, MRL-Atp6v1b1vtx/vtx mutant mice exhibit profound hearing impairment, which is associated with enlarged endolymphatic compartments of the inner ear. Mutant mice have alkaline urine but do not exhibit overt metabolic acidosis, a renal phenotype similar to that of the Atpbv1b1 knockout mouse. The abnormal inner ear phenotype of MRL- Atp6v1b1vtx/vtx mice was lost when the mutation was transferred onto the C57BL/6J (B6) background, indicating the influence of strain-specific genetic modifiers. To genetically map modifier loci in Atp6v1b1vtx/vtx mice, we analysed ABR thresholds of progeny from a backcross segregating MRL and B6 alleles. We found statistically significant linkage with a locus on Chr 13 that accounts for about 20% of the hearing threshold variation in the backcross mice. The important effect that genetic background has on the inner ear phenotype of Atp6v1b1 mutant mice provides insight into the hearing loss variability associated with dRTA caused by ATP6V1B1 mutations. Because MRL-Atp6v1b1vxt/vtx mice do not recapitulate the metabolic acidosis of dRTA patients, they provide a new genetic model for nonsyndromic deafness with enlarged vestibular aqueduct (EVA; OMIM #600791).
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Affiliation(s)
- Cong Tian
- The Jackson Laboratory, Bar Harbor, ME 04609, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME 04469, 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, Saint Louis, MO 63110, USA
| | - Angela D Schrader
- Department of Otolaryngology, Central Institute for the Deaf, Fay and Carl Simons Center for Hearing and Deafness, Washington University School of Medicine, Saint Louis, MO 63110, 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, Saint Louis, MO 63110, USA
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27
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Roesch S, Bernardinelli E, Nofziger C, Tóth M, Patsch W, Rasp G, Paulmichl M, Dossena S. Functional Testing of SLC26A4 Variants-Clinical and Molecular Analysis of a Cohort with Enlarged Vestibular Aqueduct from Austria. Int J Mol Sci 2018; 19:ijms19010209. [PMID: 29320412 PMCID: PMC5796158 DOI: 10.3390/ijms19010209] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 12/20/2017] [Accepted: 12/28/2017] [Indexed: 12/29/2022] Open
Abstract
The prevalence and spectrum of sequence alterations in the SLC26A4 gene, which codes for the anion exchanger pendrin, are population-specific and account for at least 50% of cases of non-syndromic hearing loss associated with an enlarged vestibular aqueduct. A cohort of nineteen patients from Austria with hearing loss and a radiological alteration of the vestibular aqueduct underwent Sanger sequencing of SLC26A4 and GJB2, coding for connexin 26. The pathogenicity of sequence alterations detected was assessed by determining ion transport and molecular features of the corresponding SLC26A4 protein variants. In this group, four uncharacterized sequence alterations within the SLC26A4 coding region were found. Three of these lead to protein variants with abnormal functional and molecular features, while one should be considered with no pathogenic potential. Pathogenic SLC26A4 sequence alterations were only found in 12% of patients. SLC26A4 sequence alterations commonly found in other Caucasian populations were not detected. This survey represents the first study on the prevalence and spectrum of SLC26A4 sequence alterations in an Austrian cohort and further suggests that genetic testing should always be integrated with functional characterization and determination of the molecular features of protein variants in order to unequivocally identify or exclude a causal link between genotype and phenotype.
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Affiliation(s)
- Sebastian Roesch
- Department of Otorhinolaryngology, Head and Neck Surgery, Paracelsus Medical University, Müllner Hauptstraße 48, A-5020 Salzburg, Austria.
| | - Emanuele Bernardinelli
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Strubergasse 21, A-5020 Salzburg, Austria.
| | - Charity Nofziger
- PharmGenetix Gmbh, Sonystrasse 20, A-5081 Niederalm Anif, Austria.
| | - Miklós Tóth
- Department of Otorhinolaryngology, Head & Neck Surgery and Oncology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, D-20251 Hamburg, Germany.
| | - Wolfgang Patsch
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Strubergasse 21, A-5020 Salzburg, Austria.
| | - Gerd Rasp
- Department of Otorhinolaryngology, Head and Neck Surgery, Paracelsus Medical University, Müllner Hauptstraße 48, A-5020 Salzburg, Austria.
| | - Markus Paulmichl
- Center for Health and Bioresources, Austrian Institute of Technology, Muthgasse 11, A-1190 Vienna, Austria.
| | - Silvia Dossena
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Strubergasse 21, A-5020 Salzburg, Austria.
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28
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Deletion of a Long-Range Dlx5 Enhancer Disrupts Inner Ear Development in Mice. Genetics 2018; 208:1165-1179. [PMID: 29301908 DOI: 10.1534/genetics.117.300447] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 12/09/2017] [Indexed: 12/19/2022] Open
Abstract
Distal enhancers are thought to play important roles in the spatiotemporal regulation of gene expression during embryonic development, but few predicted enhancer elements have been shown to affect transcription of their endogenous genes or to alter phenotypes when disrupted. Here, we demonstrate that a 123.6-kb deletion within the mouse Slc25a13 gene is associated with reduced transcription of Dlx5, a gene located 660 kb away. Mice homozygous for the Slc25a13 deletion mutation [named hyperspin (hspn)] have malformed inner ears and are deaf with balance defects, whereas previously reported Slc25a13 knockout mice showed no phenotypic abnormalities. Inner ears of Slc25a13hspn/hspn mice have malformations similar to those of Dlx5-/- embryos, and Dlx5 expression is severely reduced in the otocyst but not the branchial arches of Slc25a13hspn/hspn embryos, indicating that the Slc25a13hspn deletion affects otic-specific enhancers of Dlx5 In addition, transheterozygous Slc25a13+/hspn Dlx5+/- mice exhibit noncomplementation with inner ear dysmorphologies similar to those of Slc25a13hspn/hspn and Dlx5-/-embryos, verifying a cis-acting effect of the Slc25a13hspn deletion on Dlx5 expression. CRISPR/Cas9-mediated deletions of putative enhancer elements located within the Slc25a13hspn deleted region failed to phenocopy the defects of Slc25a13hspn/hspn mice, suggesting the possibility of multiple enhancers with redundant functions. Our findings in mice suggest that analogous enhancer elements in the human SLC25A13 gene may regulate DLX5 expression and underlie the hearing loss that is associated with split-hand/-foot malformation 1 syndrome. Slc25a13hspn/hspn mice provide a new animal model for studying long-range enhancer effects on Dlx5 expression in the developing inner ear.
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29
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Enerbäck S, Nilsson D, Edwards N, Heglind M, Alkanderi S, Ashton E, Deeb A, Kokash FEB, Bakhsh ARA, Van't Hoff W, Walsh SB, D'Arco F, Daryadel A, Bourgeois S, Wagner CA, Kleta R, Bockenhauer D, Sayer JA. Acidosis and Deafness in Patients with Recessive Mutations in FOXI1. J Am Soc Nephrol 2017; 29:1041-1048. [PMID: 29242249 DOI: 10.1681/asn.2017080840] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 11/15/2017] [Indexed: 11/03/2022] Open
Abstract
Maintenance of the composition of inner ear fluid and regulation of electrolytes and acid-base homeostasis in the collecting duct system of the kidney require an overlapping set of membrane transport proteins regulated by the forkhead transcription factor FOXI1. In two unrelated consanguineous families, we identified three patients with novel homozygous missense mutations in FOXI1 (p.L146F and p.R213P) predicted to affect the highly conserved DNA binding domain. Patients presented with early-onset sensorineural deafness and distal renal tubular acidosis. In cultured cells, the mutations reduced the DNA binding affinity of FOXI1, which hence, failed to adequately activate genes crucial for normal inner ear function and acid-base regulation in the kidney. A substantial proportion of patients with a clinical diagnosis of inherited distal renal tubular acidosis has no identified causative mutations in currently known disease genes. Our data suggest that recessive mutations in FOXI1 can explain the disease in a subset of these patients.
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Affiliation(s)
- Sven Enerbäck
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden;
| | - Daniel Nilsson
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Noel Edwards
- Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Mikael Heglind
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Sumaya Alkanderi
- Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Emma Ashton
- North East Thames Regional Genetic Service Laboratories, London, United Kingdom
| | - Asma Deeb
- Pediatric Services, Mafraq Hospital, Abu Dhabi, United Arab Emirates
| | - Feras E B Kokash
- College of Medicine, Gulf Medical University, Ajman, United Arab Emirates
| | - Abdul R A Bakhsh
- College of Medicine, Gulf Medical University, Ajman, United Arab Emirates
| | - William Van't Hoff
- Great Ormond Street Hospital for Children, National Health Service Foundation Trust, London, United Kingdom
| | - Stephen B Walsh
- University College London Centre for Nephrology, London, United Kingdom
| | - Felice D'Arco
- College of Medicine, Gulf Medical University, Ajman, United Arab Emirates
| | - Arezoo Daryadel
- Institute of Physiology, University of Zürich, Zurich, Switzerland; and.,National Center for Competence in Research, National Center in Competence in Research Kidney.CH, Zurich, Switzerland
| | - Soline Bourgeois
- Institute of Physiology, University of Zürich, Zurich, Switzerland; and.,National Center for Competence in Research, National Center in Competence in Research Kidney.CH, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zürich, Zurich, Switzerland; and.,National Center for Competence in Research, National Center in Competence in Research Kidney.CH, Zurich, Switzerland
| | - Robert Kleta
- Great Ormond Street Hospital for Children, National Health Service Foundation Trust, London, United Kingdom.,University College London Centre for Nephrology, London, United Kingdom
| | - Detlef Bockenhauer
- Great Ormond Street Hospital for Children, National Health Service Foundation Trust, London, United Kingdom.,University College London Centre for Nephrology, London, United Kingdom
| | - John A Sayer
- Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
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30
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Honda K, Kim SH, Kelly MC, Burns JC, Constance L, Li X, Zhou F, Hoa M, Kelley MW, Wangemann P, Morell RJ, Griffith AJ. Molecular architecture underlying fluid absorption by the developing inner ear. eLife 2017; 6. [PMID: 28994389 PMCID: PMC5634787 DOI: 10.7554/elife.26851] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 09/10/2017] [Indexed: 12/26/2022] Open
Abstract
Mutations of SLC26A4 are a common cause of hearing loss associated with enlargement of the endolymphatic sac (EES). Slc26a4 expression in the developing mouse endolymphatic sac is required for acquisition of normal inner ear structure and function. Here, we show that the mouse endolymphatic sac absorbs fluid in an SLC26A4-dependent fashion. Fluid absorption was sensitive to ouabain and gadolinium but insensitive to benzamil, bafilomycin and S3226. Single-cell RNA-seq analysis of pre- and postnatal endolymphatic sacs demonstrates two types of differentiated cells. Early ribosome-rich cells (RRCs) have a transcriptomic signature suggesting expression and secretion of extracellular proteins, while mature RRCs express genes implicated in innate immunity. The transcriptomic signature of mitochondria-rich cells (MRCs) indicates that they mediate vectorial ion transport. We propose a molecular mechanism for resorption of NaCl by MRCs during development, and conclude that disruption of this mechanism is the root cause of hearing loss associated with EES.
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Affiliation(s)
- Keiji Honda
- Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Sung Huhn Kim
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Michael C Kelly
- Developmental Neuroscience Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Joseph C Burns
- Developmental Neuroscience Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Laura Constance
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Xiangming Li
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Fei Zhou
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Michael Hoa
- Auditory Development and Restoration Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Matthew W Kelley
- Developmental Neuroscience Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Philine Wangemann
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Robert J Morell
- Genomics and Computational Biology Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Andrew J Griffith
- Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
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31
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Werth M, Schmidt-Ott KM, Leete T, Qiu A, Hinze C, Viltard M, Paragas N, Shawber CJ, Yu W, Lee P, Chen X, Sarkar A, Mu W, Rittenberg A, Lin CS, Kitajewski J, Al-Awqati Q, Barasch J. Transcription factor TFCP2L1 patterns cells in the mouse kidney collecting ducts. eLife 2017; 6. [PMID: 28577314 PMCID: PMC5484618 DOI: 10.7554/elife.24265] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 06/03/2017] [Indexed: 12/19/2022] Open
Abstract
Although most nephron segments contain one type of epithelial cell, the collecting ducts consists of at least two: intercalated (IC) and principal (PC) cells, which regulate acid-base and salt-water homeostasis, respectively. In adult kidneys, these cells are organized in rosettes suggesting functional interactions. Genetic studies in mouse revealed that transcription factor Tfcp2l1 coordinates IC and PC development. Tfcp2l1 induces the expression of IC specific genes, including specific H+-ATPase subunits and Jag1. Jag1 in turn, initiates Notch signaling in PCs but inhibits Notch signaling in ICs. Tfcp2l1 inactivation deletes ICs, whereas Jag1 inactivation results in the forfeiture of discrete IC and PC identities. Thus, Tfcp2l1 is a critical regulator of IC-PC patterning, acting cell-autonomously in ICs, and non-cell-autonomously in PCs. As a result, Tfcp2l1 regulates the diversification of cell types which is the central characteristic of 'salt and pepper' epithelia and distinguishes the collecting duct from all other nephron segments. DOI:http://dx.doi.org/10.7554/eLife.24265.001
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Affiliation(s)
- Max Werth
- Columbia University, New York, United States
| | - Kai M Schmidt-Ott
- Columbia University, New York, United States.,Max Delbruck Center for Molecular Medicine, Berlin, Germany.,Department of Nephrology and Intensive Care Medicine, Charité - Universitaetsmedizin Berlin, Berlin, Germany
| | | | - Andong Qiu
- Columbia University, New York, United States.,Tongji University, Shanghai, China
| | | | - Melanie Viltard
- Columbia University, New York, United States.,Institute for European Expertise in Physiology, Paris, France
| | - Neal Paragas
- Columbia University, New York, United States.,University of Washington, Seattle, United States
| | | | - Wenqiang Yu
- Columbia University, New York, United States.,Fudan University, Shanghai, China
| | - Peter Lee
- Columbia University, New York, United States
| | - Xia Chen
- Columbia University, New York, United States
| | - Abby Sarkar
- Columbia University, New York, United States
| | - Weiyi Mu
- Columbia University, New York, United States
| | | | | | - Jan Kitajewski
- Columbia University, New York, United States.,University of Illinois at Chicago, Chicago, United States
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32
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Møller MN, Kirkeby S, Vikeså J, Nielsen FC, Cayé-Thomasen P. The human endolymphatic sac expresses natriuretic peptides. Laryngoscope 2017; 127:E201-E208. [DOI: 10.1002/lary.26074] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 04/07/2016] [Accepted: 04/12/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Martin Nue Møller
- Department of Otorhinolaryngology, Head and Neck Surgery; Rigshospitalet; Copenhagen Denmark
| | - Svend Kirkeby
- Department of Oral Medicine, Dental School, Panum Institute; University of Copenhagen; Copenhagen Denmark
| | - Jonas Vikeså
- Center for Genomic Medicine; University of Copenhagen; Rigshospitalet Copenhagen Denmark
| | - Finn Cilius Nielsen
- Center for Genomic Medicine; University of Copenhagen; Rigshospitalet Copenhagen Denmark
| | - Per Cayé-Thomasen
- Department of Otorhinolaryngology, Head and Neck Surgery; Rigshospitalet; Copenhagen Denmark
- Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
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Smith ME, Monroe JD. Causes and Consequences of Sensory Hair Cell Damage and Recovery in Fishes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 877:393-417. [PMID: 26515323 DOI: 10.1007/978-3-319-21059-9_17] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Sensory hair cells are the mechanotransductive receptors that detect gravity, sound, and vibration in all vertebrates. Damage to these sensitive receptors often results in deficits in vestibular function and hearing. There are currently two main reasons for studying the process of hair cell loss in fishes. First, fishes, like other non-mammalian vertebrates, have the ability to regenerate hair cells that have been damaged or lost via exposure to ototoxic chemicals or acoustic overstimulation. Thus, they are used as a biomedical model to understand the process of hair cell death and regeneration and find therapeutics that treat or prevent human hearing loss. Secondly, scientists and governmental natural resource managers are concerned about the potential effects of intense anthropogenic sounds on aquatic organisms, including fishes. Dr. Arthur N. Popper and his students, postdocs and research associates have performed pioneering experiments in both of these lines of fish hearing research. This review will discuss the current knowledge regarding the causes and consequences of both lateral line and inner ear hair cell damage in teleost fishes.
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Affiliation(s)
- Michael E Smith
- Department of Biology, Western Kentucky University, Bowling Green, KY, 42101, USA.
| | - J David Monroe
- Department of Biology, Western Kentucky University, Bowling Green, KY, 42101, USA.
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de Moraes VCS, Bernardinelli E, Zocal N, Fernandez JA, Nofziger C, Castilho AM, Sartorato EL, Paulmichl M, Dossena S. Reduction of Cellular Expression Levels Is a Common Feature of Functionally Affected Pendrin (SLC26A4) Protein Variants. Mol Med 2016; 22:41-53. [PMID: 26752218 DOI: 10.2119/molmed.2015.00226] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/04/2016] [Indexed: 11/06/2022] Open
Abstract
Sequence alterations in the pendrin gene (SLC26A4) leading to functionally affected protein variants are frequently involved in the pathogenesis of syndromic and nonsyndromic deafness. Considering the high number of SLC26A4 sequence alterations reported to date, discriminating between functionally affected and unaffected pendrin protein variants is essential in contributing to determine the genetic cause of deafness in a given patient. In addition, identifying molecular features common to the functionally affected protein variants can be extremely useful to design future molecule-directed therapeutic approaches. Here we show the functional and molecular characterization of six previously uncharacterized pendrin protein variants found in a cohort of 58 Brazilian deaf patients. Two variants (p.T193I and p.L445W) were undetectable in the plasma membrane, completely retained in the endoplasmic reticulum and showed no transport function; four (p.P142L, p.G149R, p.C282Y and p.Q413R) showed reduced function and significant, although heterogeneous, expression levels in the plasma membrane. Importantly, total expression levels of all of the functionally affected protein variants were significantly reduced with respect to the wild-type and a fully functional variant (p.R776C), regardless of their subcellular localization. Interestingly, reduction of expression may also reduce the transport activity of variants with an intrinsic gain of function (p.Q413R). As reduction of overall cellular abundance was identified as a common molecular feature of pendrin variants with affected function, the identification of strategies to prevent reduction in expression levels may represent a crucial step of potential future therapeutic interventions aimed at restoring the transport activity of dysfunctional pendrin variants.
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Affiliation(s)
- Vanessa C S de Moraes
- Center of Molecular Biology and Genetic Engineering (CBMEG), Molecular Biology Laboratory, State University of Campinas, UNICAMP, Campinas/São Paulo, Brazil
| | - Emanuele Bernardinelli
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | - Nathalia Zocal
- Center of Molecular Biology and Genetic Engineering (CBMEG), Molecular Biology Laboratory, State University of Campinas, UNICAMP, Campinas/São Paulo, Brazil
| | - Jhonathan A Fernandez
- Center of Molecular Biology and Genetic Engineering (CBMEG), Molecular Biology Laboratory, State University of Campinas, UNICAMP, Campinas/São Paulo, Brazil
| | - Charity Nofziger
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | - Arthur M Castilho
- Otology, Audiology and Implantable Ear Prostheses, State University of Campinas, UNICAMP, Campinas/São Paulo, Brazil
| | - Edi L Sartorato
- Center of Molecular Biology and Genetic Engineering (CBMEG), Molecular Biology Laboratory, State University of Campinas, UNICAMP, Campinas/São Paulo, Brazil
| | - Markus Paulmichl
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | - Silvia Dossena
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
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Birol O, Ohyama T, Edlund RK, Drakou K, Georgiades P, Groves AK. The mouse Foxi3 transcription factor is necessary for the development of posterior placodes. Dev Biol 2015; 409:139-151. [PMID: 26550799 DOI: 10.1016/j.ydbio.2015.09.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 09/22/2015] [Indexed: 02/01/2023]
Abstract
The inner ear develops from the otic placode, one of the cranial placodes that arise from a region of ectoderm adjacent to the anterior neural plate called the pre-placodal domain. We have identified a Forkhead family transcription factor, Foxi3, that is expressed in the pre-placodal domain and down-regulated when the otic placode is induced. We now show that Foxi3 mutant mice do not form otic placodes as evidenced by expression changes in early molecular markers and the lack of thickened placodal ectoderm, an otic cup or otocyst. Some preplacodal genes downstream of Foxi3-Gata3, Six1 and Eya1-are not expressed in the ectoderm of Foxi3 mutant mice, and the ectoderm exhibits signs of increased apoptosis. We also show that Fgf signals from the hindbrain and cranial mesoderm, which are necessary for otic placode induction, are received by pre-placodal ectoderm in Foxi3 mutants, but do not initiate otic induction. Finally, we show that the epibranchial placodes that develop in close proximity to the otic placode and the mandibular division of the trigeminal ganglion are missing in Foxi3 mutants. Our data suggest that Foxi3 is necessary to prime pre-placodal ectoderm for the correct interpretation of inductive signals for the otic and epibranchial placodes.
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Affiliation(s)
- Onur Birol
- Program in Developmental Biology, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston, TX 77030, USA
| | - Takahiro Ohyama
- USC Caruso Department of Otolaryngology - Head & Neck Surgery, Keck Medicine of USC, University of Southern California, 1501 San Pablo Street, Los Angeles, CA 90033-4503, USA; Zilkha Neurogenetic Institute, Keck Medicine of USC, University of Southern California, 1501 San Pablo Street, Los Angeles, CA 90033-4503, USA
| | - Renée K Edlund
- Program in Developmental Biology, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston, TX 77030, USA
| | - Katerina Drakou
- Department of Biological Sciences, University of Cyprus, 1 University Avenue, P.O. Box 20537, 1678 Nicosia, Cyprus
| | - Pantelis Georgiades
- Department of Biological Sciences, University of Cyprus, 1 University Avenue, P.O. Box 20537, 1678 Nicosia, Cyprus
| | - Andrew K Groves
- Program in Developmental Biology, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston, TX 77030, USA; Department of Neurosc ience, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston, TX 77030, USA.
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Asymmetric and unilateral hearing loss in children. Cell Tissue Res 2015; 361:271-8. [PMID: 26004144 DOI: 10.1007/s00441-015-2208-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 05/06/2015] [Indexed: 12/11/2022]
Abstract
Asymmetric and unilateral hearing losses in children have traditionally been underappreciated, but health care practitioners are now beginning to understand their effect on development and the underlying pathophysiologic mechanisms. The common wisdom among medical and educational professionals has been that at least one normal-hearing or near-normal-hearing ear was sufficient for typical speech and language development in children. The objective of this review is to illustrate, to the non-otolaryngologist, the consequences of asymmetric and unilateral hearing loss in children on developmental and educational outcomes. Etiology, detection, and management are also discussed. Lastly, implications for further research are considered.
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Edlund RK, Birol O, Groves AK. The role of foxi family transcription factors in the development of the ear and jaw. Curr Top Dev Biol 2015; 111:461-95. [PMID: 25662269 DOI: 10.1016/bs.ctdb.2014.11.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The mammalian outer, middle, and inner ears have different embryonic origins and evolved at different times in the vertebrate lineage. The outer ear is derived from first and second branchial arch ectoderm and mesoderm, the middle ear ossicles are derived from neural crest mesenchymal cells that invade the first and second branchial arches, whereas the inner ear and its associated vestibule-acoustic (VIIIth) ganglion are derived from the otic placode. In this chapter, we discuss recent findings in the development of these structures and describe the contributions of members of a Forkhead transcription factor family, the Foxi family to their formation. Foxi transcription factors are critical for formation of the otic placode, survival of the branchial arch neural crest, and developmental remodeling of the branchial arch ectoderm.
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Affiliation(s)
- Renée K Edlund
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Onur Birol
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Andrew K Groves
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA; Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA.
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Renal acid-base regulation: new insights from animal models. Pflugers Arch 2014; 467:1623-41. [PMID: 25515081 DOI: 10.1007/s00424-014-1669-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 12/16/2022]
Abstract
Because majority of biological processes are dependent on pH, maintaining systemic acid-base balance is critical. The kidney contributes to systemic acid-base regulation, by reabsorbing HCO3 (-) (both filtered by glomeruli and generated within a nephron) and acidifying urine. Abnormalities in those processes will eventually lead to a disruption in systemic acid-base balance and provoke metabolic acid-base disorders. Research over the past 30 years advanced our understanding on cellular and molecular mechanisms responsible for those processes. In particular, a variety of transgenic animal models, where target genes are deleted either globally or conditionally, provided significant insights into how specific transporters are contributing to the renal acid-base regulation. Here, we broadly overview the mechanisms of renal ion transport participating to acid-base regulation, with emphasis on data obtained from transgenic mice models.
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Soleimani M. The multiple roles of pendrin in the kidney. Nephrol Dial Transplant 2014; 30:1257-66. [PMID: 25281699 DOI: 10.1093/ndt/gfu307] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 08/25/2014] [Indexed: 12/30/2022] Open
Abstract
The [Formula: see text] exchanger pendrin (SLC26A4, PDS) is located on the apical membrane of B-intercalated cells in the kidney cortical collecting duct and the connecting tubules and mediates the secretion of bicarbonate and the reabsorption of chloride. Given its dual function of bicarbonate secretion and chloride reabsorption in the distal tubules, it was thought that pendrin plays important roles in systemic acid-base balance and electrolyte and vascular volume homeostasis under basal conditions. Mice with the genetic deletion of pendrin or humans with inactivating mutations in PDS gene, however, do not display excessive salt and fluid wasting or altered blood pressure under baseline conditions. Very recent reports have unmasked the basis of incongruity between the mild phenotype in mutant mice and the role of pendrin as an important player in salt reabsorption in the distal tubule. These studies demonstrate that pendrin and the Na-Cl cotransporter (NCC; SLC12A3) cross compensate for the loss of each other, therefore masking the role that each transporter plays in salt reabsorption under baseline conditions. In addition, pendrin regulates calcium reabsorption in the distal tubules. Furthermore, combined deletion of pendrin and NCC not only causes severe volume depletion but also results in profound calcium wasting and luminal calcification in medullary collecting ducts. Based on studies in pathophysiological states and the examination of genetically engineered mouse models, the evolving picture points to important roles for pendrin (SLC26A4) in kidney physiology and in disease states. This review summarizes recent advances in the characterization of pendrin and the multiple roles it plays in the kidney, with emphasis on its essential roles in several diverse physiological processes, including chloride homeostasis, vascular volume and blood pressure regulation, calcium excretion and kidney stone formation.
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Affiliation(s)
- Manoocher Soleimani
- Center on Genetics of Transport and Epithelial Biology, University of Cincinnati, Cincinnati, OH, USA Research Services, Veterans Affairs Medical Center, Cincinnati, OH, USA Department of Medicine, University of Cincinnati, Cincinnati, OH, USA
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Abstract
A forward genetic screen of N-ethyl-N-nitrosourea mutagenized Xenopus tropicalis has identified an inner ear mutant named eclipse (ecl). Mutants developed enlarged otic vesicles and various defects of otoconia development; they also showed abnormal circular and inverted swimming patterns. Positional cloning identified specificity protein 8 (sp8), which was previously found to regulate limb and brain development. Two different loss-of-function approaches using transcription activator-like effector nucleases and morpholino oligonucleotides confirmed that the ecl mutant phenotype is caused by down-regulation of sp8. Depletion of sp8 resulted in otic dysmorphogenesis, such as uncompartmentalized and enlarged otic vesicles, epithelial dilation with abnormal sensory end organs. When overexpressed, sp8 was sufficient to induce ectopic otic vesicles possessing sensory hair cells, neurofilament innervation in a thickened sensory epithelium, and otoconia, all of which are found in the endogenous otic vesicle. We propose that sp8 is an important factor for initiation and elaboration of inner ear development.
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Ladsous M, Vlaeminck-Guillem V, Dumur V, Vincent C, Dubrulle F, Dhaenens CM, Wémeau JL. Analysis of the thyroid phenotype in 42 patients with Pendred syndrome and nonsyndromic enlargement of the vestibular aqueduct. Thyroid 2014; 24:639-48. [PMID: 24224479 DOI: 10.1089/thy.2013.0164] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Pendred syndrome (PS), a recessive disorder caused by mutations in the SLC26A4 (PDS) gene, is associated with deafness and goiter. SLC26A4 mutations have also been identified in patients exhibiting isolated sensorineural hearing loss without apparent thyroid abnormality (nonsyndromic enlargement of the vestibular aqueduct; nonsyndromic EVA). Our aim was to describe systematically the thyroidal phenotypes and the SLC26A4 genotypes of patients presenting with PS or nonsyndromic EVA. METHODS Nineteen patients with PS and 23 patients with nonsyndromic EVA, aged 5-53 years, were included. They underwent thyroid evaluation (physical examination, biological thyroid function tests, measurement of thyroglobulin level, thyroid ultrasonography, and thyroid (123)I scintigraphy with perchlorate discharge test), otological evaluation, and SLC26A4 mutation screening. RESULTS In 19 patients with PS, goiter was identified in 15 (79%) and hypothyroidism in 15 (79%); hypothyroidism was subclinical in four patients and congenital in six patients. The perchlorate discharge test (PDT) was positive in 10/16 (63%). Morphological evaluation of the inner ear using MRI and/or CT showed bilateral EVA in 15/15 PS patients. Mutation screening revealed two SLC26A4 mutant alleles in all 19 PS patients that were homozygous in two families and compound heterozygous in 12 families. In the 23 patients with nonsyndromic EVA, systematic thyroid evaluation found no abnormalities except for slightly increased thyroglobulin levels in two patients. SLC26A4 mutations were identified in 9/23 (39%). Mutations were biallelic in two (compound heterozygous) and monoallelic in seven patients. CONCLUSION The thyroid phenotype is widely variable in PS. SLC26A4 mutation screening is needed in patients exhibiting PS or nonsyndromic EVA. PS is associated with biallelic SLC26A4 mutations and nonsyndromic EVA with no, monoallelic, or biallelic SLC26A4 mutations. Systematic thyroid evaluation is recommended in patients with nonsyndromic EVA associated with one or two SLC26A4 mutations. We propose using a combination of three parameters to define and diagnose PS: (i) sensorineural deafness with bilateral EVA; (ii) thyroid abnormality comprising goiter and/or hypothyroidism and/or a positive PDT; (iii) biallelic SLC26A4 mutations.
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Affiliation(s)
- Miriam Ladsous
- 1 Department of Endocrinology, Regional University Hospital Center (CHRU) of Lille, Lille, France
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Edlund RK, Ohyama T, Kantarci H, Riley BB, Groves AK. Foxi transcription factors promote pharyngeal arch development by regulating formation of FGF signaling centers. Dev Biol 2014; 390:1-13. [PMID: 24650709 DOI: 10.1016/j.ydbio.2014.03.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 03/10/2014] [Indexed: 01/12/2023]
Abstract
The bones of the vertebrate face develop from transient embryonic branchial arches that are populated by cranial neural crest cells. We have characterized a mouse mutant for the Forkhead family transcription factor Foxi3, which is expressed in branchial ectoderm and endoderm. Foxi3 mutant mice are not viable and display severe branchial arch-derived facial skeleton defects, including absence of all but the most distal tip of the mandible and complete absence of the inner, middle and external ear structures. Although cranial neural crest cells of Foxi3 mutants are able to migrate, populate the branchial arches, and display some elements of correct proximo-distal patterning, they succumb to apoptosis from embryonic day 9.75 onwards. We show this cell death correlates with a delay in expression of Fgf8 in branchial arch ectoderm and a failure of neural crest cells in the arches to express FGF-responsive genes. Zebrafish foxi1 is also expressed in branchial arch ectoderm and endoderm, and morpholino knock-down of foxi1 also causes apoptosis of neural crest in the branchial arches. We show that heat shock induction of fgf3 in zebrafish arch tissue can rescue cell death in foxi1 morphants. Our results suggest that Foxi3 may play a role in the establishment of signaling centers in the branchial arches that are required for neural crest survival, patterning and the subsequent development of branchial arch derivatives.
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Affiliation(s)
- Renée K Edlund
- Program in Developmental Biology, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston TX 77030
| | - Takahiro Ohyama
- Division of Cell Biology and Genetics, House Research Institute, 2100 W 3rd St., Los Angeles, CA 90057
| | - Husniye Kantarci
- Biology Department, Texas A&M University, College Station, TX 77843-3258
| | - Bruce B Riley
- Biology Department, Texas A&M University, College Station, TX 77843-3258
| | - Andrew K Groves
- Program in Developmental Biology, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston TX 77030.,Department of Molecular and Human Genetics, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston TX 77030.,Department of Neuroscience, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston TX 77030
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Raft S, Andrade LR, Shao D, Akiyama H, Henkemeyer M, Wu DK. Ephrin-B2 governs morphogenesis of endolymphatic sac and duct epithelia in the mouse inner ear. Dev Biol 2014; 390:51-67. [PMID: 24583262 DOI: 10.1016/j.ydbio.2014.02.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 02/19/2014] [Indexed: 02/03/2023]
Abstract
Control over ionic composition and volume of the inner ear luminal fluid endolymph is essential for normal hearing and balance. Mice deficient in either the EphB2 receptor tyrosine kinase or the cognate transmembrane ligand ephrin-B2 (Efnb2) exhibit background strain-specific vestibular-behavioral dysfunction and signs of abnormal endolymph homeostasis. Using various loss-of-function mouse models, we found that Efnb2 is required for growth and morphogenesis of the embryonic endolymphatic epithelium, a precursor of the endolymphatic sac (ES) and duct (ED), which mediate endolymph homeostasis. Conditional inactivation of Efnb2 in early-stage embryonic ear tissues disrupted cell proliferation, cell survival, and epithelial folding at the origin of the endolymphatic epithelium. This correlated with apparent absence of an ED, mis-localization of ES ion transport cells relative to inner ear sensory organs, dysplasia of the endolymph fluid space, and abnormally formed otoconia (extracellular calcite-protein composites) at later stages of embryonic development. A comparison of Efnb2 and Notch signaling-deficient mutant phenotypes indicated that these two signaling systems have distinct and non-overlapping roles in ES/ED development. Homozygous deletion of the Efnb2 C-terminus caused abnormalities similar to those found in the conditional Efnb2 null homozygote. Analyses of fetal Efnb2 C-terminus deletion heterozygotes found mis-localized ES ion transport cells only in the genetic background exhibiting vestibular dysfunction. We propose that developmental dysplasias described here are a gene dose-sensitive cause of the vestibular dysfunction observed in EphB-Efnb2 signaling-deficient mice.
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Affiliation(s)
- Steven Raft
- Section on Sensory Cell Regeneration and Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Leonardo R Andrade
- Laboratory of Biomineralization, Institute of Biomedical Sciences, CCS, Universidade Federal do Rio de Janeiro, RJ 21941-902, Brazil
| | - Dongmei Shao
- Department of Otolaryngology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Haruhiko Akiyama
- Department of Orthopedics, Gifu University, Gifu City 501-1194, Japan
| | - Mark Henkemeyer
- Department of Developmental Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Doris K Wu
- Section on Sensory Cell Regeneration and Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA.
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Wangemann P. Mouse models for pendrin-associated loss of cochlear and vestibular function. Cell Physiol Biochem 2013; 32:157-65. [PMID: 24429822 PMCID: PMC4415819 DOI: 10.1159/000356635] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2013] [Indexed: 01/17/2023] Open
Abstract
The human gene SLC26A4 and the mouse ortholog Slc26a4 code for the protein pendrin, which is an anion exchanger expressed in apical membranes of selected epithelia. In the inner ear, pendrin is expressed in the cochlea, the vestibular labyrinth and the endolymphatic sac. Loss-of-function and hypo-functional mutations cause an enlargement of the vestibular aqueduct (EVA) and sensorineural hearing loss. The relatively high prevalence of SLC26A4 mutations provides a strong imperative to develop rational interventions that delay, ameliorate or prevent pendrin-associated loss of cochlear and vestibular function. This review summarizes recent studies in mouse models that have been developed to delineate the role of pendrin in the physiology of hearing and balance and that have brought forward the concept that a temporally and spatially limited therapy may be sufficient to secure a life-time of normal hearing in children bearing mutations of SLC26A4.
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Affiliation(s)
- Philine Wangemann
- Anatomy & Physiology Department, Kansas State University, Manhattan, Kansas, USA
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Geng FS, Abbas L, Baxendale S, Holdsworth CJ, Swanson AG, Slanchev K, Hammerschmidt M, Topczewski J, Whitfield TT. Semicircular canal morphogenesis in the zebrafish inner ear requires the function of gpr126 (lauscher), an adhesion class G protein-coupled receptor gene. Development 2013; 140:4362-74. [PMID: 24067352 PMCID: PMC4007713 DOI: 10.1242/dev.098061] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Morphogenesis of the semicircular canal ducts in the vertebrate inner ear is a dramatic example of epithelial remodelling in the embryo, and failure of normal canal development results in vestibular dysfunction. In zebrafish and Xenopus, semicircular canal ducts develop when projections of epithelium, driven by extracellular matrix production, push into the otic vesicle and fuse to form pillars. We show that in the zebrafish, extracellular matrix gene expression is high during projection outgrowth and then rapidly downregulated after fusion. Enzymatic disruption of hyaluronan in the projections leads to their collapse and a failure to form pillars: as a result, the ears swell. We have cloned a zebrafish mutant, lauscher (lau), identified by its swollen ear phenotype. The primary defect in the ear is abnormal projection outgrowth and a failure of fusion to form the semicircular canal pillars. Otic expression of extracellular matrix components is highly disrupted: several genes fail to become downregulated and remain expressed at abnormally high levels into late larval stages. The lau mutations disrupt gpr126, an adhesion class G protein-coupled receptor gene. Expression of gpr126 is similar to that of sox10, an ear and neural crest marker, and is partially dependent on sox10 activity. Fusion of canal projections and downregulation of otic versican expression in a hypomorphic lau allele can be restored by cAMP agonists. We propose that Gpr126 acts through a cAMP-mediated pathway to control the outgrowth and adhesion of canal projections in the zebrafish ear via the regulation of extracellular matrix gene expression.
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Affiliation(s)
- Fan-Suo Geng
- MRC Centre for Developmental and Biomedical Genetics and Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
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Landa P, Differ AM, Rajput K, Jenkins L, Bitner-Glindzicz M. Lack of significant association between mutations of KCNJ10 or FOXI1 and SLC26A4 mutations in Pendred syndrome/enlarged vestibular aqueducts. BMC MEDICAL GENETICS 2013; 14:85. [PMID: 23965030 PMCID: PMC3765178 DOI: 10.1186/1471-2350-14-85] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 08/06/2013] [Indexed: 12/11/2022]
Abstract
Background Pendred syndrome is a common autosomal recessive disorder causing deafness. Features include sensorineural hearing impairment, goitre, enlarged vestibular aqueducts (EVA) and occasionally Mondini dysplasia. Hearing impairment and EVA may occur in the absence of goitre or thyroid dyshormonogensis in a condition known as non-syndromic EVA. A significant number of patients with Pendred syndrome and non-syndromic EVA show only one mutation in SLC26A4. Two genes, KCNJ10, encoding an inwardly rectifying potassium channel and FOXI1, a transcriptional factor gene, are thought to play a role in the disease phenotypes. Methods Using Polymerase Chain Reaction and Sanger sequencing, sixty-eight patients with monoallelic mutations of SLC26A4 were tested for mutations in KCNJ10 and FOXI1. Results Two variants were observed in the KCNJ10 gene, p.Arg271Cys in three patients and p.Arg18Gln in one patient; only one variant, p.Arg123Trp was observed in the FOXI1 gene in a single patient. Both p.Arg271Cys and p.Arg18Gln are likely to be polymorphisms as judged by their frequency in the general population. Conclusion Therefore we found no evidence for a significant association between mutations of KCNJ10 and FOXI1 with SLC26A4. It was also observed that the variant, p.Arg271Cys in KCNJ10, previously thought to have a protective effect against seizure susceptibility, was found in a patient with Pendred syndrome with co-existing epilepsy.
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Affiliation(s)
- Priya Landa
- North East Thames Regional Genetics Service Laboratory, Great Ormond Street Hospital for Children NHS Foundation Trust, 37 Queen Square,York House, London WC1N 3BH, UK
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Li X, Sanneman JD, Harbidge DG, Zhou F, Ito T, Nelson R, Picard N, Chambrey R, Eladari D, Miesner T, Griffith AJ, Marcus DC, Wangemann P. SLC26A4 targeted to the endolymphatic sac rescues hearing and balance in Slc26a4 mutant mice. PLoS Genet 2013; 9:e1003641. [PMID: 23874234 PMCID: PMC3708829 DOI: 10.1371/journal.pgen.1003641] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 06/01/2013] [Indexed: 12/13/2022] Open
Abstract
Mutations of SLC26A4 are a common cause of human hearing loss associated with enlargement of the vestibular aqueduct. SLC26A4 encodes pendrin, an anion exchanger expressed in a variety of epithelial cells in the cochlea, the vestibular labyrinth and the endolymphatic sac. Slc26a4 (Δ/Δ) mice are devoid of pendrin and develop a severe enlargement of the membranous labyrinth, fail to acquire hearing and balance, and thereby provide a model for the human phenotype. Here, we generated a transgenic mouse line that expresses human SLC26A4 controlled by the promoter of ATP6V1B1. Crossing this transgene into the Slc26a4 (Δ/Δ) line restored protein expression of pendrin in the endolymphatic sac without inducing detectable expression in the cochlea or the vestibular sensory organs. The transgene prevented abnormal enlargement of the membranous labyrinth, restored a normal endocochlear potential, normal pH gradients between endolymph and perilymph in the cochlea, normal otoconia formation in the vestibular labyrinth and normal sensory functions of hearing and balance. Our study demonstrates that restoration of pendrin to the endolymphatic sac is sufficient to restore normal inner ear function. This finding in conjunction with our previous report that pendrin expression is required for embryonic development but not for the maintenance of hearing opens the prospect that a spatially and temporally limited therapy will restore normal hearing in human patients carrying a variety of mutations of SLC26A4.
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Affiliation(s)
- Xiangming Li
- Anatomy & Physiology Department, Kansas State University, Manhattan, Kansas, United States of America
| | - Joel D. Sanneman
- Anatomy & Physiology Department, Kansas State University, Manhattan, Kansas, United States of America
| | - Donald G. Harbidge
- Anatomy & Physiology Department, Kansas State University, Manhattan, Kansas, United States of America
| | - Fei Zhou
- Anatomy & Physiology Department, Kansas State University, Manhattan, Kansas, United States of America
| | - Taku Ito
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, United States of America
| | - Raoul Nelson
- Department of Pediatrics, Division of Nephrology, School of Medicine, University of Utah, Salt Lake City, Utah, United States of America
| | - Nicolas Picard
- Inserm, UMRS 970, Centre de recherche PARCC (Paris centre de recherche cardiovasculaire); Faculté de Médecine Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Régine Chambrey
- Inserm, UMRS 970, Centre de recherche PARCC (Paris centre de recherche cardiovasculaire); Faculté de Médecine Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Dominique Eladari
- Inserm, UMRS 970, Centre de recherche PARCC (Paris centre de recherche cardiovasculaire); Faculté de Médecine Paris Descartes, Sorbonne Paris Cité, Paris, France
- Département de Physiologie, HEGP, AP-HP, Paris, France
| | - Tracy Miesner
- Comparative Medicine Group, Kansas State University, Manhattan, Kansas, United States of America
| | - Andrew J. Griffith
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, United States of America
| | - Daniel C. Marcus
- Anatomy & Physiology Department, Kansas State University, Manhattan, Kansas, United States of America
| | - Philine Wangemann
- Anatomy & Physiology Department, Kansas State University, Manhattan, Kansas, United States of America
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Hans S, Irmscher A, Brand M. Zebrafish Foxi1 provides a neuronal ground state during inner ear induction preceding the Dlx3b/4b-regulated sensory lineage. Development 2013; 140:1936-45. [PMID: 23571216 DOI: 10.1242/dev.087718] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Vertebrate inner ear development is a complex process that involves the induction of a common territory for otic and epibranchial precursors and their subsequent segregation into otic and epibranchial cell fates. In zebrafish, the otic-epibranchial progenitor domain (OEPD) is induced by Fgf signaling in a Foxi1- and Dlx3b/4b-dependent manner, but the functional differences of Foxi1 and Dlx3b/4b in subsequent cell fate specifications within the developing inner ear are poorly understood. Based on pioneer tracking (PioTrack), a novel Cre-dependent genetic lineage tracing method, and genetic data, we show that the competence to embark on a neuronal or sensory fate is provided sequentially and very early during otic placode induction. Loss of Foxi1 prevents neuronal precursor formation without affecting hair cell specification, whereas loss of Dlx3b/4b inhibits hair cell but not neuronal precursor formation. Consistently, in Dlx3b/4b- and Sox9a-deficient b380 mutants almost all otic epithelial fates are absent, including sensory hair cells, and the remaining otic cells adopt a neuronal fate. Furthermore, the progenitors of the anterior lateral line ganglia also arise from the OEPD in a Foxi1-dependent manner but are unaffected in the absence of Dlx3b/4b or in b380 mutants. Thus, in addition to otic fate Foxi1 provides neuronal competence during OEPD induction prior to and independently of the Dlx3b/4b-mediated sensory fate of the developing inner ear.
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Affiliation(s)
- Stefan Hans
- Technische Universität Dresden, Biotechnology Center and DFG-Center for Regenerative Therapies Dresden Cluster of Excellence, Tatzberg 47-49, Dresden, Germany.
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Al-Awqati Q. Cell biology of the intercalated cell in the kidney. FEBS Lett 2013; 587:1911-4. [PMID: 23684635 DOI: 10.1016/j.febslet.2013.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 05/02/2013] [Accepted: 05/02/2013] [Indexed: 12/13/2022]
Abstract
The intercalated cell of the collecting tubule of the mammalian kidney is specialized for the transport of H(+) and HCO3. They exist in two forms; one specialized for acid secretion and the other secretes HCO3 into the urine. We discovered many years ago that feeding animals an acid diet converts the HCO3 secreting form to an acid secreting type. Here I discuss the molecular basis of this transformation. The conversion of the cell types is mediated by an extracellular matrix protein hensin (also known as DMBT1). However much remains to be identified in the differentiation of these cells.
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Affiliation(s)
- Qais Al-Awqati
- Department of Medicine, College of Physicians & Surgeons of Columbia University, 630 W 168th Str., New York, NY 10032, USA.
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