1
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Huang Y, Zhang L, Sun Y, Liu Q, Chen J, Qian X, Gao X, Zhu GJ, Wan G. A human-specific cytotoxic neopeptide generated by the deafness gene Cingulin. J Genet Genomics 2024:S1673-8527(24)00195-4. [PMID: 39098598 DOI: 10.1016/j.jgg.2024.07.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 07/22/2024] [Accepted: 07/26/2024] [Indexed: 08/06/2024]
Abstract
Accumulation of mutant proteins in cells can induce proteinopathies and cause functional damage to organs. Recently, the Cingulin (CGN) protein has been shown to maintain the morphology of cuticular plates of inner ear hair cells and a frameshift mutation in CGN causes autosomal dominant nonsyndromic hearing loss. Here, we find that the mutant CGN proteins form insoluble aggregates which accumulate intracellularly and lead to cell death. Expression of the mutant CGN in the inner ear results in severe hair cell death and hearing loss in mice, resembling the auditory phenotype in human patients. Interestingly, a human-specific residue (V1112) in the neopeptide generated by the frameshift mutation is critical for the aggregation and cytotoxicity of the mutant human CGN. Moreover, the expression of heat shock factor 1 (HSF1) decreases the accumulation of insoluble mutant CGN aggregates and rescues cell death. In summary, these findings identify mutant-specific toxic polypeptides as a disease-causing mechanism of the deafness mutation in CGN, which can be targeted by the expression of the cell chaperone response regulator HSF1.
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Affiliation(s)
- Yuhang Huang
- MOE Key Laboratory of Model Animal for Disease Study, Department of Otolaryngology Head and Neck Surgery, Jiangsu Provincial Key Medical Discipline (Laboratory), The Affiliated Drum Tower Hospital of Medical School, Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China; Jiangsu Key Laboratory of Molecular Medicine and National Resource Center for Mutant Mice of China, Nanjing University, Nanjing, Jiangsu 210061, China
| | - Linqing Zhang
- MOE Key Laboratory of Model Animal for Disease Study, Department of Otolaryngology Head and Neck Surgery, Jiangsu Provincial Key Medical Discipline (Laboratory), The Affiliated Drum Tower Hospital of Medical School, Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China; Jiangsu Key Laboratory of Molecular Medicine and National Resource Center for Mutant Mice of China, Nanjing University, Nanjing, Jiangsu 210061, China
| | - Yuecen Sun
- MOE Key Laboratory of Model Animal for Disease Study, Department of Otolaryngology Head and Neck Surgery, Jiangsu Provincial Key Medical Discipline (Laboratory), The Affiliated Drum Tower Hospital of Medical School, Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China; Jiangsu Key Laboratory of Molecular Medicine and National Resource Center for Mutant Mice of China, Nanjing University, Nanjing, Jiangsu 210061, China
| | - Qing Liu
- MOE Key Laboratory of Model Animal for Disease Study, Department of Otolaryngology Head and Neck Surgery, Jiangsu Provincial Key Medical Discipline (Laboratory), The Affiliated Drum Tower Hospital of Medical School, Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China; Jiangsu Key Laboratory of Molecular Medicine and National Resource Center for Mutant Mice of China, Nanjing University, Nanjing, Jiangsu 210061, China; Research Institute of Otolaryngology, No. 321 Zhongshan Road, Nanjing, Jiangsu 210061, China
| | - Jie Chen
- MOE Key Laboratory of Model Animal for Disease Study, Department of Otolaryngology Head and Neck Surgery, Jiangsu Provincial Key Medical Discipline (Laboratory), The Affiliated Drum Tower Hospital of Medical School, Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China; Research Institute of Otolaryngology, No. 321 Zhongshan Road, Nanjing, Jiangsu 210061, China
| | - Xiaoyun Qian
- MOE Key Laboratory of Model Animal for Disease Study, Department of Otolaryngology Head and Neck Surgery, Jiangsu Provincial Key Medical Discipline (Laboratory), The Affiliated Drum Tower Hospital of Medical School, Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China; Research Institute of Otolaryngology, No. 321 Zhongshan Road, Nanjing, Jiangsu 210061, China
| | - Xia Gao
- MOE Key Laboratory of Model Animal for Disease Study, Department of Otolaryngology Head and Neck Surgery, Jiangsu Provincial Key Medical Discipline (Laboratory), The Affiliated Drum Tower Hospital of Medical School, Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China; Research Institute of Otolaryngology, No. 321 Zhongshan Road, Nanjing, Jiangsu 210061, China.
| | - Guang-Jie Zhu
- MOE Key Laboratory of Model Animal for Disease Study, Department of Otolaryngology Head and Neck Surgery, Jiangsu Provincial Key Medical Discipline (Laboratory), The Affiliated Drum Tower Hospital of Medical School, Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China; Research Institute of Otolaryngology, No. 321 Zhongshan Road, Nanjing, Jiangsu 210061, China.
| | - Guoqiang Wan
- MOE Key Laboratory of Model Animal for Disease Study, Department of Otolaryngology Head and Neck Surgery, Jiangsu Provincial Key Medical Discipline (Laboratory), The Affiliated Drum Tower Hospital of Medical School, Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China; Jiangsu Key Laboratory of Molecular Medicine and National Resource Center for Mutant Mice of China, Nanjing University, Nanjing, Jiangsu 210061, China; Research Institute of Otolaryngology, No. 321 Zhongshan Road, Nanjing, Jiangsu 210061, China.
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2
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Takahashi S, Homma K. The molecular principles underlying diverse functions of the SLC26 family of proteins. J Biol Chem 2024; 300:107261. [PMID: 38582450 PMCID: PMC11078650 DOI: 10.1016/j.jbc.2024.107261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/07/2024] [Accepted: 03/30/2024] [Indexed: 04/08/2024] Open
Abstract
Mammalian SLC26 proteins are membrane-based anion transporters that belong to the large SLC26/SulP family, and many of their variants are associated with hereditary diseases. Recent structural studies revealed a strikingly similar homodimeric molecular architecture for several SLC26 members, implying a shared molecular principle. Now a new question emerges as to how these structurally similar proteins execute diverse physiological functions. In this study, we sought to identify the common versus distinct molecular mechanism among the SLC26 proteins using both naturally occurring and artificial missense changes introduced to SLC26A4, SLC26A5, and SLC26A9. We found: (i) the basic residue at the anion binding site is essential for both anion antiport of SLC26A4 and motor functions of SLC26A5, and its conversion to a nonpolar residue is crucial but not sufficient for the fast uncoupled anion transport in SLC26A9; (ii) the conserved polar residues in the N- and C-terminal cytosolic domains are likely involved in dynamic hydrogen-bonding networks and are essential for anion antiport of SLC26A4 but not for motor (SLC26A5) and uncoupled anion transport (SLC26A9) functions; (iii) the hydrophobic interaction between each protomer's last transmembrane helices, TM14, is not of functional significance in SLC26A9 but crucial for the functions of SLC26A4 and SLC26A5, likely contributing to optimally orient the axis of the relative movements of the core domain with respect to the gate domains within the cell membrane. These findings advance our understanding of the molecular mechanisms underlying the diverse physiological roles of the SLC26 family of proteins.
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Affiliation(s)
- Satoe Takahashi
- Department of Otolaryngology - Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; Center for Mechanical Excitability, The University of Chicago, Chicago, Illinois, USA
| | - Kazuaki Homma
- Department of Otolaryngology - Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; Center for Mechanical Excitability, The University of Chicago, Chicago, Illinois, USA; The Hugh Knowles Center for Clinical and Basic Science in Hearing and Its Disorders, Northwestern University, Evanston, Illinois, USA.
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3
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Lee D, Hong JH. Chloride/Multiple Anion Exchanger SLC26A Family: Systemic Roles of SLC26A4 in Various Organs. Int J Mol Sci 2024; 25:4190. [PMID: 38673775 PMCID: PMC11050216 DOI: 10.3390/ijms25084190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 03/31/2024] [Accepted: 04/08/2024] [Indexed: 04/28/2024] Open
Abstract
Solute carrier family 26 member 4 (SLC26A4) is a member of the SLC26A transporter family and is expressed in various tissues, including the airway epithelium, kidney, thyroid, and tumors. It transports various ions, including bicarbonate, chloride, iodine, and oxalate. As a multiple-ion transporter, SLC26A4 is involved in the maintenance of hearing function, renal function, blood pressure, and hormone and pH regulation. In this review, we have summarized the various functions of SLC26A4 in multiple tissues and organs. Moreover, the relationships between SLC26A4 and other channels, such as cystic fibrosis transmembrane conductance regulator, epithelial sodium channel, and sodium chloride cotransporter, are highlighted. Although the modulation of SLC26A4 is critical for recovery from malfunctions of various organs, development of specific inducers or agonists of SLC26A4 remains challenging. This review contributes to providing a better understanding of the role of SLC26A4 and development of therapeutic approaches for the SLC26A4-associated hearing loss and SLC26A4-related dysfunction of various organs.
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Affiliation(s)
| | - Jeong Hee Hong
- Department of Health Sciences and Technology, GAIHST (Gachon Advanced Institute for Health Sciences and Technology), Lee Gil Ya Cancer and Diabetes Institute, Gachon University, 155 Getbeolro, Yeonsu-gu, Incheon 21999, Republic of Korea;
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4
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Takahashi S, Kojima T, Wasano K, Homma K. Functional Studies of Deafness-Associated Pendrin and Prestin Variants. Int J Mol Sci 2024; 25:2759. [PMID: 38474007 PMCID: PMC10931795 DOI: 10.3390/ijms25052759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 03/14/2024] Open
Abstract
Pendrin and prestin are evolutionary-conserved membrane proteins that are essential for normal hearing. Dysfunction of these proteins results in hearing loss in humans, and numerous deafness-associated pendrin and prestin variants have been identified in patients. However, the pathogenic impacts of many of these variants are ambiguous. Here, we report results from our ongoing efforts to experimentally characterize pendrin and prestin variants using in vitro functional assays. With previously established fluorometric anion transport assays, we determined that many of the pendrin variants identified on transmembrane (TM) 10, which contains the essential anion binding site, and on the neighboring TM9 within the core domain resulted in impaired anion transport activity. We also determined the range of functional impairment in three deafness-associated prestin variants by measuring nonlinear capacitance (NLC), a proxy for motor function. Using the results from our functional analyses, we also evaluated the performance of AlphaMissense (AM), a computational tool for predicting the pathogenicity of missense variants. AM prediction scores correlated well with our experimental results; however, some variants were misclassified, underscoring the necessity of experimentally assessing the effects of variants. Together, our experimental efforts provide invaluable information regarding the pathogenicity of deafness-associated pendrin and prestin variants.
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Affiliation(s)
- Satoe Takahashi
- Department of Otolaryngology—Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Takashi Kojima
- Department of Otolaryngology—Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Department of Otolaryngology, Head and Neck Surgery, National Hospital Organization Tochigi Medical Center, Tochigi 320-0057, Japan
| | - Koichiro Wasano
- Department of Otolaryngology—Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Department of Otolaryngology, Head and Neck Surgery, Tokai University School of Medicine, Isehara 259-1193, Japan
| | - Kazuaki Homma
- Department of Otolaryngology—Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- The Hugh Knowles Center for Clinical and Basic Science in Hearing and Its Disorders, Northwestern University, Evanston, IL 60208, USA
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5
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Takahashi S, Kojima T, Wasano K, Homma K. Functional studies of deafness-associated pendrin and prestin variants. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.23.576877. [PMID: 38328051 PMCID: PMC10849616 DOI: 10.1101/2024.01.23.576877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Pendrin and prestin are evolutionary conserved membrane proteins that are essential for normal hearing. Pendrin is an anion transporter required for normal development and maintenance of ion homeostasis in the inner ear, while prestin is a voltage-dependent motor responsible for cochlear amplification essential for high sensitivity and frequency selectivity of mammalian hearing. Dysfunction of these proteins result in hearing loss in humans, and numerous deafness-associated pendrin and prestin variants have been identified in patients. However, the pathogenic impacts of many of these variants are ambiguous. Here we report results from our ongoing efforts in experimentally characterizing pendrin and prestin variants using in vitro functional assays, providing invaluable information regarding their pathogenicity.
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6
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Takahashi S, Homma K. The molecular principles underlying diverse functions of the SLC26 family of proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.10.570988. [PMID: 38106153 PMCID: PMC10723444 DOI: 10.1101/2023.12.10.570988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Mammalian SLC26 proteins are membrane-based anion transporters that belong to the large SLC26/SulP family, and many of their variants are associated with hereditary diseases. Recent structural studies revealed a strikingly similar homodimeric molecular architecture for several SLC26 members, implying a shared molecular principle. Now a new question emerges as to how these structurally similar proteins execute diverse physiological functions. In this study we sought to identify the common vs. distinct molecular mechanism among the SLC26 proteins using both naturally occurring and artificial missense changes introduced to SLC26A4, SLC26A5, and SLC26A9. We found: (i) the basic residue at the anion binding site is essential for both anion antiport of SLC26A4 and motor functions of SLC26A5, and its conversion to a nonpolar residue is crucial but not sufficient for the fast uncoupled anion transport in SLC26A9; (ii) the conserved polar residues in the N- and C-terminal cytosolic domains are likely involved in dynamic hydrogen-bonding networks and are essential for anion antiport of SLC26A4 but not for motor (SLC26A5) and uncoupled anion transport (SLC26A9) functions; (iii) the hydrophobic interaction between each protomer's last transmembrane helices, TM14, is not of functional significance in SLC26A9 but crucial for the functions of SLC26A4 and SLC26A5, likely contributing to optimally orient the axis of the relative movements of the core domain with respect to the gate domains within the cell membrane. These findings advance our understanding of the molecular mechanisms underlying the diverse physiological roles of the SLC26 family of proteins.
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7
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Jung J, Noh SH, Jo S, Song D, Kang MJ, Shin MH, Lee HJ, Pyun JC, Namkung W, Han G, Lee MG, Choi JY. Novel small molecule-mediated restoration of the surface expression and anion exchange activity of mutated pendrin causing Pendred syndrome and DFNB4. Biomed Pharmacother 2023; 167:115445. [PMID: 37690388 DOI: 10.1016/j.biopha.2023.115445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 08/28/2023] [Accepted: 09/04/2023] [Indexed: 09/12/2023] Open
Abstract
Variants in SLC26A4 (pendrin) are the most common reasons for genetic hearing loss and vestibular dysfunction in East Asians. In patients with Pendred syndrome and DFNB4 (autosomal recessive type of genetic hearing loss 4), caused by variants in SLC26A4, the hearing function is residual at birth and deteriorates over several years, with no curative treatment for these disorders. In the present study, we revealed that a novel small molecule restores the expression and function of mutant pendrin. High-throughput screening of 54,000 small molecules was performed. We observed that pendrin corrector (PC2-1) increased the surface expression and anion exchange activity of p.H723R pendrin (H723R-PDS), the most prevalent genetic variant that causes Pendred syndrome and DFNB4. Furthermore, in endogenous H723R-PDS-expressing human nasal epithelial cells, PC2-1 significantly increased the surface expression of pendrin. PC2-1 exhibited high membrane permeability in vitro and high micromolar concentrations in the cochlear perilymph in vivo. In addition, neither inhibition of Kv11.1 activity in the human ether-a-go-go-related gene assay nor cell toxicity in the cell proliferation assay was observed at a high PC2-1 concentration (30 μM). These preclinical data support the hypothesis of the druggability of mutant pendrin using the novel corrector molecule PC2-1. In conclusion, PC2-1 may be a new therapeutic molecule for ameliorating hearing loss and treating vestibular disorders in patients with Pendred syndrome or DFNB4.
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Affiliation(s)
- Jinsei Jung
- Department of Otorhinolaryngology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Won-Sang Lee Institute for Hearing Loss, Seoul 03722, Republic of Korea
| | - Shin Hye Noh
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Sungwoo Jo
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Republic of Korea
| | - Doona Song
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Republic of Korea; Department of Integrated OMICS for Biomedical Science, Yonsei University, Seoul 03722, Republic of Korea; Translational Research Center for Protein Function Control, Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Min Jin Kang
- Department of Otorhinolaryngology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Won-Sang Lee Institute for Hearing Loss, Seoul 03722, Republic of Korea
| | - Mi Hwa Shin
- Department of Otorhinolaryngology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Won-Sang Lee Institute for Hearing Loss, Seoul 03722, Republic of Korea
| | - Hyun Jae Lee
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, USA
| | - Jae-Chul Pyun
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Wan Namkung
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Republic of Korea.
| | - Gyoonhee Han
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Republic of Korea; Department of Integrated OMICS for Biomedical Science, Yonsei University, Seoul 03722, Republic of Korea; Translational Research Center for Protein Function Control, Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea.
| | - Min Goo Lee
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Department of Pharmacology, Graduate School of Medical Science, Brain Korea 21 Project, Republic of Korea, Seoul 03722, Republic of Korea.
| | - Jae Young Choi
- Department of Otorhinolaryngology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Won-Sang Lee Institute for Hearing Loss, Seoul 03722, Republic of Korea.
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8
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Liu Q, Zhang X, Huang H, Chen Y, Wang F, Hao A, Zhan W, Mao Q, Hu Y, Han L, Sun Y, Zhang M, Liu Z, Li GL, Zhang W, Shu Y, Sun L, Chen Z. Asymmetric pendrin homodimer reveals its molecular mechanism as anion exchanger. Nat Commun 2023; 14:3012. [PMID: 37230976 DOI: 10.1038/s41467-023-38303-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 04/23/2023] [Indexed: 05/27/2023] Open
Abstract
Pendrin (SLC26A4) is an anion exchanger expressed in the apical membranes of selected epithelia. Pendrin ablation causes Pendred syndrome, a genetic disorder associated with sensorineural hearing loss, hypothyroid goiter, and reduced blood pressure. However its molecular structure has remained unknown, limiting our understanding of the structural basis of transport. Here, we determine the cryo-electron microscopy structures of mouse pendrin with symmetric and asymmetric homodimer conformations. The asymmetric homodimer consists of one inward-facing protomer and the other outward-facing protomer, representing coincident uptake and secretion- a unique state of pendrin as an electroneutral exchanger. The multiple conformations presented here provide an inverted alternate-access mechanism for anion exchange. The structural and functional data presented here disclose the properties of an anion exchange cleft and help understand the importance of disease-associated variants, which will shed light on the pendrin exchange mechanism.
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Affiliation(s)
- Qianying Liu
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Xiang Zhang
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Hui Huang
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yuxin Chen
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Fang Wang
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Aihua Hao
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Wuqiang Zhan
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Qiyu Mao
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yuxia Hu
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Lin Han
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yifang Sun
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Meng Zhang
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Zhimin Liu
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Geng-Lin Li
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Weijia Zhang
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yilai Shu
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China.
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China.
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China.
- Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China.
| | - Lei Sun
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China.
- Shanghai Institute of Infectious Disease and Biosecurity, Shanghai, 200032, China.
- Shanghai Key Laboratory of Medical Epigenetics, Shanghai, 200032, China.
| | - Zhenguo Chen
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China.
- Shanghai Institute of Infectious Disease and Biosecurity, Shanghai, 200032, China.
- Shanghai Key Laboratory of Medical Epigenetics, Shanghai, 200032, China.
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9
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Matulevičius A, Bernardinelli E, Brownstein Z, Roesch S, Avraham KB, Dossena S. Molecular Features of SLC26A4 Common Variant p.L117F. J Clin Med 2022; 11:jcm11195549. [PMID: 36233414 PMCID: PMC9570580 DOI: 10.3390/jcm11195549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/16/2022] [Accepted: 09/19/2022] [Indexed: 11/16/2022] Open
Abstract
The SLC26A4 gene, which encodes the anion exchanger pendrin, is involved in determining syndromic (Pendred syndrome) and non-syndromic (DFNB4) autosomal recessive hearing loss. SLC26A4 c.349C>T, p.L117F is a relatively common allele in the Ashkenazi Jewish community, where its minor allele frequency is increased compared to other populations. Although segregation and allelic data support the pathogenicity of this variant, former functional tests showed characteristics that were indistinguishable from those of the wild-type protein. Here, we applied a triad of cell-based assays, i.e., measurement of the ion transport activity by a fluorometric method, determination of the subcellular localization by confocal microscopy, and assessment of protein expression levels, to conclusively assign or exclude the pathogenicity of SLC26A4 p.L117F. This protein variant showed a moderate, but significant, reduction in ion transport function, a partial retention in the endoplasmic reticulum, and a strong reduction in expression levels as a consequence of an accelerated degradation by the Ubiquitin Proteasome System, all supporting pathogenicity. The functional and molecular features of human pendrin p.L117F were recapitulated by the mouse ortholog, thus indicating that a mouse carrying this variant might represent a good model of Pendred syndrome/DFNB4.
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Affiliation(s)
- Arnoldas Matulevičius
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Emanuele Bernardinelli
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Zippora Brownstein
- Department of Human Molecular Genetics & Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Sebastian Roesch
- Department of Otorhinolaryngology, Head and Neck Surgery, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Karen B. Avraham
- Department of Human Molecular Genetics & Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
- Correspondence: (K.B.A.); (S.D.); Tel.: +972-3-6407030 (K.B.A.); +43-662-2420-80560 (S.D.)
| | - Silvia Dossena
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, 5020 Salzburg, Austria
- Correspondence: (K.B.A.); (S.D.); Tel.: +972-3-6407030 (K.B.A.); +43-662-2420-80560 (S.D.)
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10
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SLC26A4 Mutation Promotes Cell Apoptosis by Inducing Pendrin Transfer, Reducing Cl- Transport, and Inhibiting PI3K/Akt/mTOR Pathway. BIOMED RESEARCH INTERNATIONAL 2022; 2022:6496799. [PMID: 36072472 PMCID: PMC9444440 DOI: 10.1155/2022/6496799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/03/2022] [Indexed: 11/18/2022]
Abstract
Objective. Pendrin is encoded by SLC26A4, which is expressed in the apical membrane of inner ear epithelial cells and drives chloride reabsorption in the apical septum. In the inner ear, pendrin dysfunction and hypofunctional mutations lead to vestibular aqueduct (EVA) enlargement and sensory neural hearing loss. Mutations in SLC26A4 are a common reason of deafness. However, the underlying mechanisms of SLC26A4 mutants in hearing loss remain unknown. Methods. In the present study, pEGFP-N1 carrying wild-type and mutant SLC26A4 (c.85G>A, c.2006A>T, and c.853G>A) were transfected into HEK-293T cells. GFP fluorescence and GFP levels were determined. SLC26A4 mRNA levels were examined by quantitative real-time polymerase chain reaction (qRT-PCR). Then, the expression of chloride intracellular channel 1 (CLIC1) and CLIC2 was measured by Immunofluorescence assay. Intracellular chloride concentration and apoptotic rate were analyzed by flow cytometry. The levels of membrane/cytoplasmic pendrin, apoptosis-associated proteins, and the PI3K/Akt/mTOR pathway members were determined by Western blot. Results. Constructed SLC26A4 mutant 1 (c.85G>A), SLC26A4 mutant 2 (c.2006A>T), and SLC26A4 mutant 3 (c.853G>A). The wild-type and 3 mutations were stably expressed in HEK-293T. SLC26A4 mRNA expression was significantly increased after transfection with wild-type SLC26A4 and mutant SLC26A4 compared with the untransfected vector group (
). Compared with the vector group, the expression levels of membrane pendrin, cytoplasmic pendrin, CLIC1, CLIC2, Bcl-2, p-PI3K, p-Akt, and p-mTOR were upregulated. Compared with the vector group, the chloride concentration, cell apoptotic rate, and the expression levels of caspase-3, caspase-9, and Bax were downregulated. Compared with the vector group, the above effects of SLC26A4 were reversed after the SLC26A4 mutant. Conclusion. After SLC26A4 mutation, pendrin was transferred from the membrane, the chloride intracellular channel function was reduced, and the excessive accumulation of chloride in the cytoplasm induced cell apoptosis by inhibited PI3K/Akt/mTOR pathway phosphorylation.
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Park H, Seo SK, Sim J, Hwang SJ, Kim YJ, Shin DH, Jang DG, Noh SH, Park P, Ko SH, Shin MH, Choi JY, Ito Y, Kang C, Lee JM, Lee MG. TMED3 Complex Mediates ER Stress-Associated Secretion of CFTR, Pendrin, and SARS-CoV-2 Spike. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2105320. [PMID: 35748162 PMCID: PMC9350134 DOI: 10.1002/advs.202105320] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 05/06/2022] [Indexed: 05/13/2023]
Abstract
Under ER stress conditions, the ER form of transmembrane proteins can reach the plasma membrane via a Golgi-independent unconventional protein secretion (UPS) pathway. However, the targeting mechanisms of membrane proteins for UPS are unknown. Here, this study reports that TMED proteins play a critical role in the ER stress-associated UPS of transmembrane proteins. The gene silencing results reveal that TMED2, TMED3, TMED9 and TMED10 are involved in the UPS of transmembrane proteins, such as CFTR, pendrin and SARS-CoV-2 Spike. Subsequent mechanistic analyses indicate that TMED3 recognizes the ER core-glycosylated protein cargos and that the heteromeric TMED2/3/9/10 complex mediates their UPS. Co-expression of all four TMEDs improves, while each single expression reduces, the UPS and ion transport function of trafficking-deficient ΔF508-CFTR and p.H723R-pendrin, which cause cystic fibrosis and Pendred syndrome, respectively. In contrast, TMED2/3/9/10 silencing reduces SARS-CoV-2 viral release. These results provide evidence for a common role of TMED3 and related TMEDs in the ER stress-associated, Golgi-independent secretion of transmembrane proteins.
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Affiliation(s)
- Hak Park
- Department of PharmacologySeverance Biomedical Science InstituteYonsei University College of MedicineSeoul03722Korea
- Department of Laboratory MedicineSeverance HospitalYonsei University College of MedicineSeoul03722Korea
| | - Soo Kyung Seo
- Department of PharmacologySeverance Biomedical Science InstituteYonsei University College of MedicineSeoul03722Korea
- Graduate School of Medical ScienceBrain Korea 21 ProjectYonsei University College of MedicineSeoul03722Korea
| | - Ju‐Ri Sim
- Department of PharmacologySeverance Biomedical Science InstituteYonsei University College of MedicineSeoul03722Korea
- Graduate School of Medical ScienceBrain Korea 21 ProjectYonsei University College of MedicineSeoul03722Korea
| | - Su Jin Hwang
- Graduate School of Medical ScienceBrain Korea 21 ProjectYonsei University College of MedicineSeoul03722Korea
- Department of Microbiology and ImmunologyInstitute for Immunology and Immunological DiseasesYonsei University College of MedicineSeoul03722Korea
| | - Ye Jin Kim
- Department of PharmacologySeverance Biomedical Science InstituteYonsei University College of MedicineSeoul03722Korea
- Graduate School of Medical ScienceBrain Korea 21 ProjectYonsei University College of MedicineSeoul03722Korea
| | - Dong Hoon Shin
- Department of PharmacologySeverance Biomedical Science InstituteYonsei University College of MedicineSeoul03722Korea
| | - Dong Geon Jang
- Department of PharmacologySeverance Biomedical Science InstituteYonsei University College of MedicineSeoul03722Korea
- Graduate School of Medical ScienceBrain Korea 21 ProjectYonsei University College of MedicineSeoul03722Korea
| | - Shin Hye Noh
- Department of PharmacologySeverance Biomedical Science InstituteYonsei University College of MedicineSeoul03722Korea
| | - Pil‐Gu Park
- Department of Microbiology and ImmunologyInstitute for Immunology and Immunological DiseasesYonsei University College of MedicineSeoul03722Korea
| | - Si Hwan Ko
- Department of Microbiology and ImmunologyInstitute for Immunology and Immunological DiseasesYonsei University College of MedicineSeoul03722Korea
| | - Mi Hwa Shin
- Department of OtorhinolaryngologyYonsei University College of MedicineSeoul03722Korea
| | - Jae Young Choi
- Department of OtorhinolaryngologyYonsei University College of MedicineSeoul03722Korea
| | - Yukishige Ito
- Cluster for Pioneering ResearchRIKENWakoSaitama351‐0198Japan
- Graduate School of ScienceOsaka UniversityToyonakaOsaka560‐0043Japan
| | - Chung‐Min Kang
- Department of Pediatric DentistryCollege of DentistryYonsei UniversitySeoul03722Korea
| | - Jae Myun Lee
- Graduate School of Medical ScienceBrain Korea 21 ProjectYonsei University College of MedicineSeoul03722Korea
- Department of Microbiology and ImmunologyInstitute for Immunology and Immunological DiseasesYonsei University College of MedicineSeoul03722Korea
| | - Min Goo Lee
- Department of PharmacologySeverance Biomedical Science InstituteYonsei University College of MedicineSeoul03722Korea
- Graduate School of Medical ScienceBrain Korea 21 ProjectYonsei University College of MedicineSeoul03722Korea
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Murakoshi M, Koike Y, Koyama S, Usami S, Kamiya K, Ikeda K, Haga Y, Tsumoto K, Nakamura H, Hirasawa N, Ishihara K, Wada H. Effects of salicylate derivatives on localization of p.H723R allele product of SLC26A4. Auris Nasus Larynx 2022; 49:928-937. [PMID: 35305848 DOI: 10.1016/j.anl.2022.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 01/24/2022] [Accepted: 03/04/2022] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Pendrin is a transmembrane protein encoded by the SLC26A4 gene that functions in maintaining ion concentrations in the endolymph of the inner ear, most likely by acting as a chloride/bicarbonate transporter. Variants in the SLC26A4 gene are responsible for sensorineural hearing loss. Although pendrin localizes to the plasma membrane, we previously identified that 8 missense allele products of SLC26A4 were retained in the intracellular region and lost their anion exchange function. We also found that 10 mM salicylate induced the translocation of 4 out of 8 allele products from the intracellular region to the plasma membrane and restored their anion exchanger activity. However, since 10 mM salicylate exhibits cytotoxicity, the use of chemical compounds with less cell toxicity is needed. In the present study, therefore, salicylate derivatives were used as the chemical compounds and their effects on the p.H723R allele products of SLC26A4 were investigated. METHODS HEK293 cells were transfected with the cDNA of p.H723R. Cell proliferation, viability and toxicity assays were performed to investigate the response and health of cells in culture after treatment with four types of salicylate derivatives, i.e., 2-hydroxybenzyl alcohol, 2,3-dihydroxybenzoic acid, 2'-hydroxyacetophenone and methyl salicylate. The effects of these salicylate derivatives on the localization of the p.H723R were investigated by immunofluorescence microscopy. RESULTS The application of 10 mM salicylate showed an increase in cell toxicity and decrease in cell viability, leading to a significant decrease in cell proliferation. In contrast, the application of 1 mM salicylate derivatives did not show any significant increase in cell toxicity and decrease in cell viability, corresponding to a logarithmic increase in cell concentration with an increase in culture time. Immunofluorescence experiments showed that the p.H723R retained in the endoplasmic reticulum (ER). Among the salicylate derivatives applied, 2-hydroxybenzyl alcohol induced the translocation of p.H723R from the ER to the plasma membrane 3 h after its application. CONCLUSION The results obtained showed that 2-hydroxybenzyl alcohol restored the localization of the p.H723R allele products of SLC26A4 from the ER to the plasma membrane at a concentration of 1 mM by 3 h after its administration with less cytotoxicity than 10 mM salicylate.
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Affiliation(s)
- Michio Murakoshi
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan; Division of Mechanical Science and Engineering, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan.
| | - Yuhi Koike
- Division of Mechanical Science and Engineering, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan
| | - Shin Koyama
- Kansokan-kyoto.com, Kyoto, Japan; Division of Creative Research and Development of Humanosphere, Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto, Japan
| | - Shinichi Usami
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Japan
| | - Kazusaku Kamiya
- Department of Otorhinolaryngology, Juntendo University School of Medicine, Tokyo, Japan
| | - Katsuhisa Ikeda
- Department of Otorhinolaryngology, Juntendo University School of Medicine, Tokyo, Japan
| | - Yoichi Haga
- Department of Biomedical Engineering, Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
| | - Kohei Tsumoto
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Hiroyuki Nakamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Noriyasu Hirasawa
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Kenji Ishihara
- Laboratory of Medical Science, Course for School Nurse Teacher, Faculty of Education, Ibaraki University, Mito, Japan
| | - Hiroshi Wada
- Department of Intelligent Information System, Tohoku Bunka Gakuen University, Sendai, Japan
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SLC26A9 as a Potential Modifier and Therapeutic Target in Cystic Fibrosis Lung Disease. Biomolecules 2022; 12:biom12020202. [PMID: 35204703 PMCID: PMC8961553 DOI: 10.3390/biom12020202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/21/2022] [Accepted: 01/22/2022] [Indexed: 11/16/2022] Open
Abstract
SLC26A9 belongs to the solute carrier family 26 (SLC26), which comprises membrane proteins involved in ion transport mechanisms. On the basis of different preliminary findings, including the phenotype of SlC26A9-deficient mice and its possible role as a gene modifier of the human phenotype and treatment response, SLC26A9 has emerged as one of the most interesting alternative targets for the treatment of cystic fibrosis (CF). However, despite relevant clues, some open issues and controversies remain. The lack of specific pharmacological modulators, the elusive expression reported in the airways, and its complex relationships with CFTR and the CF phenotype prevent us from conclusively understanding the contribution of SLC26A9 in human lung physiology and its real potential as a therapeutic target in CF. In this review, we summarized the various studies dealing with SLC26A9 expression, molecular structure, and function as an anion channel or transporter; its interaction and functional relationships with CFTR; and its role as a gene modifier and tried to reconcile them in order to highlight the current understanding and the gap in knowledge regarding the contribution of SLC26A9 to human lung physiology and CF disease and treatment.
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Different Rates of the SLC26A4-Related Hearing Loss in Two Indigenous Peoples of Southern Siberia (Russia). Diagnostics (Basel) 2021; 11:diagnostics11122378. [PMID: 34943614 PMCID: PMC8699871 DOI: 10.3390/diagnostics11122378] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/13/2021] [Accepted: 12/13/2021] [Indexed: 12/14/2022] Open
Abstract
Hereditary hearing loss (HL) is known to be highly locus/allelic heterogeneous, and the prevalence of different HL forms significantly varies among populations worldwide. Investigation of region-specific landscapes of hereditary HL is important for local healthcare and medical genetic services. Mutations in the SLC26A4 gene leading to nonsyndromic recessive deafness (DFNB4) and Pendred syndrome are common genetic causes of hereditary HL, at least in some Asian populations. We present for the first time the results of a thorough analysis of the SLC26A4 gene by Sanger sequencing in the large cohorts of patients with HL of unknown etiology belonging to two neighboring indigenous Turkic-speaking Siberian peoples (Tuvinians and Altaians). A definite genetic diagnosis based on the presence of biallelic SLC26A4 mutations was established for 28.2% (62/220) of all enrolled Tuvinian patients vs. 4.3% (4/93) of Altaian patients. The rate of the SLC26A4-related HL in Tuvinian patients appeared to be one of the highest among populations worldwide. The SLC26A4 mutational spectrum was characterized by the presence of Asian-specific mutations c.919-2A>G and c.2027T>A (p.Leu676Gln), predominantly found in Tuvinian patients, and c.2168A>G (p.His723Arg), which was only detected in Altaian patients. In addition, a novel pathogenic variant c.1545T>G (p.Phe515Leu) was found with high frequency in Tuvinian patients. Overall, based on the findings of this study and our previous research, we were able to uncover the genetic causes of HL in 50.5% of Tuvinian patients and 34.5% of Altaian patients.
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15
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Hu CJ, Lu YC, Tsai CY, Chan YH, Lin PH, Lee YS, Yu IS, Lin SW, Liu TC, Hsu CJ, Yang TH, Cheng YF, Wu CC. Insights into phenotypic differences between humans and mice with p.T721M and other C-terminal variants of the SLC26A4 gene. Sci Rep 2021; 11:20983. [PMID: 34697379 PMCID: PMC8545921 DOI: 10.1038/s41598-021-00448-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/22/2021] [Indexed: 11/17/2022] Open
Abstract
Recessive variants of the SLC26A4 gene are an important cause of hereditary hearing impairment. Several transgenic mice with different Slc26a4 variants have been generated. However, none have recapitulated the auditory phenotypes in humans. Of the SLC26A4 variants identified thus far, the p.T721M variant is of interest, as it appears to confer a more severe pathogenicity than most of the other missense variants, but milder pathogenicity than non-sense and frameshift variants. Using a genotype-driven approach, we established a knock-in mouse model homozygous for p.T721M. To verify the pathogenicity of p.T721M, we generated mice with compound heterozygous variants by intercrossing Slc26a4+/T721M mice with Slc26a4919-2A>G/919-2A>G mice, which segregated the c.919-2A > G variant with abolished Slc26a4 function. We then performed serial audiological assessments, vestibular evaluations, and inner ear morphological studies. Surprisingly, both Slc26a4T721M/T721M and Slc26a4919-2A>G/T721M showed normal audiovestibular functions and inner ear morphology, indicating that p.T721M is non-pathogenic in mice and a single p.T721M allele is sufficient to maintain normal inner ear physiology. The evidence together with previous reports on mouse models with Slc26a4 p.C565Y and p.H723R variants, support our speculation that the absence of audiovestibular phenotypes in these mouse models could be attributed to different protein structures at the C-terminus of human and mouse pendrin.
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Affiliation(s)
- Chin-Ju Hu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.,Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA, 02115, USA
| | - Ying-Chang Lu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan
| | - Cheng-Yu Tsai
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan
| | - Yen-Hui Chan
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.,Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, 427, Taiwan
| | - Pei-Hsuan Lin
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan
| | - Yi-Shan Lee
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan
| | - I-Shing Yu
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center for Medical Excellence, National Taiwan University, Taipei, 100, Taiwan
| | - Shu-Wha Lin
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center for Medical Excellence, National Taiwan University, Taipei, 100, Taiwan
| | - Tien-Chen Liu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.,Department of Otolaryngology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - Chuan-Jen Hsu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.,Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, 427, Taiwan
| | - Ting-Hua Yang
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.
| | - Yen-Fu Cheng
- Department of Medical Research, Taipei Veteran General Hospital, 201, Sec.2, Shi-Pai Rd, Taipei, 112, Taiwan. .,Department of Otolaryngology-Head and Neck Surgery, Taipei Veteran General Hospital, Taipei, 112, Taiwan. .,School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan.
| | - Chen-Chi Wu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan. .,Department of Otolaryngology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan. .,Department of Medical Research, National Taiwan University Hospital Hsin-Chu Branch, Hsinchu, 302, Taiwan.
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16
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Hu CJ, Lu YC, Yang TH, Chan YH, Tsai CY, Yu IS, Lin SW, Liu TC, Cheng YF, Wu CC, Hsu CJ. Toward the Pathogenicity of the SLC26A4 p.C565Y Variant Using a Genetically Driven Mouse Model. Int J Mol Sci 2021; 22:2789. [PMID: 33801843 PMCID: PMC8001573 DOI: 10.3390/ijms22062789] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/05/2021] [Accepted: 03/05/2021] [Indexed: 11/19/2022] Open
Abstract
Recessive variants of the SLC26A4 gene are globally a common cause of hearing impairment. In the past, cell lines and transgenic mice were widely used to investigate the pathogenicity associated with SLC26A4 variants. However, discrepancies in pathogenicity between humans and cell lines or transgenic mice were documented for some SLC26A4 variants. For instance, the p.C565Y variant, which was reported to be pathogenic in humans, did not exhibit functional pathogenic consequences in cell lines. To address the pathogenicity of p.C565Y, we used a genotype-based approach in which we generated knock-in mice that were heterozygous (Slc26a4+/C565Y), homozygous (Slc26a4C565Y/C565Y), and compound heterozygous (Slc26a4919-2A>G/C565Y) for this variant. Subsequent phenotypic characterization revealed that mice with these genotypes demonstrated normal auditory and vestibular functions, and normal inner-ear morphology and pendrin expression. These findings indicate that the p.C565Y variant is nonpathogenic for mice, and that a single p.C565Y allele is sufficient to maintain normal inner-ear physiology in mice. Our results highlight the differences in pathogenicity associated with certain SLC26A4 variants between transgenic mice and humans, which should be considered when interpreting the results of animal studies for SLC26A4-related deafness.
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Affiliation(s)
- Chin-Ju Hu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA 02115, USA
| | - Ying-Chang Lu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Department of Medical Research, Taipei Veteran General Hospital, Taipei 112, Taiwan
| | - Ting-Hua Yang
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
| | - Yen-Hui Chan
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung 427, Taiwan
| | - Cheng-Yu Tsai
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
| | - I-Shing Yu
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center for Medical Excellence, National Taiwan University, Taipei 100, Taiwan; (I-S.Y.); (S.-W.L.)
| | - Shu-Wha Lin
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center for Medical Excellence, National Taiwan University, Taipei 100, Taiwan; (I-S.Y.); (S.-W.L.)
| | - Tien-Chen Liu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
| | - Yen-Fu Cheng
- Department of Medical Research, Taipei Veteran General Hospital, Taipei 112, Taiwan
- Department of Otolaryngology-Head and Neck Surgery, Taipei Veteran General Hospital, Taipei 112, Taiwan
- Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Chen-Chi Wu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Department of Medical Genetics, National Taiwan University Hospital, Taipei 100, Taiwan
- Department of Otolaryngology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Chuan-Jen Hsu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung 427, Taiwan
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Chi X, Jin X, Chen Y, Lu X, Tu X, Li X, Zhang Y, Lei J, Huang J, Huang Z, Zhou Q, Pan X. Structural insights into the gating mechanism of human SLC26A9 mediated by its C-terminal sequence. Cell Discov 2020; 6:55. [PMID: 32818062 PMCID: PMC7417587 DOI: 10.1038/s41421-020-00193-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 07/07/2020] [Indexed: 11/25/2022] Open
Abstract
The human SLC26 transporter family exhibits various transport characteristics, and family member SLC26A9 performs multiple roles, including acting as Cl-/HCO3- exchangers, Cl- channels, and Na+ transporters. Some mutations of SLC26A9 are correlated with abnormalities in respiration and digestion systems. As a potential target colocalizing with CFTR in cystic fibrosis patients, SLC26A9 is of great value in drug development. Here, we present a cryo-EM structure of the human SLC26A9 dimer at 2.6 Å resolution. A segment at the C-terminal end is bound to the entry of the intracellular vestibule of the putative transport pathway, which has been proven by electrophysiological experiments to be a gating modulator. Multiple chloride and sodium ions are resolved in the high-resolution structure, identifying novel ion-binding pockets for the first time. Together, our structure takes important steps in elucidating the structural features and regulatory mechanism of SLC26A9, with potential significance in the treatment of cystic fibrosis.
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Affiliation(s)
- Ximin Chi
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Xueqin Jin
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Yun Chen
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Xiaoli Lu
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Xinyu Tu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, 100191 China
| | - Xiaorong Li
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Yuanyuan Zhang
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Jianlin Lei
- Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Jing Huang
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, 100191 China
- Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, 100191 China
| | - Qiang Zhou
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Xiaojing Pan
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084 China
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18
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Cao S, Sha Y, Ke P, Li T, Yuan W, Huang X. Deafness Gene Mutations in Newborns in the Foshan Area of South China With Bloodspot-Based Genetic Screening Tests. Am J Audiol 2020; 29:165-169. [PMID: 32208970 DOI: 10.1044/2020_aja-19-00094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Purpose The aim of this study was to determine the rate of deafness gene mutations in the Foshan area of South China. Method We enrolled the infants delivered in Foshan Maternity and Children's Healthcare Hospital. Deafness gene mutation was detected by HibriMax method. Our study tested 47,538 newborns within 3 days after birth, including 13 sites in four genes: GJB2 (c.35 del G, c.176 del 16, c.235 del C, c.299 del AT, c.155 del TCTG), GJB3 (c.583 C>T), SLC26A4 (c.2168 A>G, c.919-2 A>G, c.1299 C>T), and mtDNA 12S rRNA (m.1555 A>G, m.1494 C>T, m.12201 T>C, m.7445 A>G). The birth condition of infants was collected, including sex, low or high birth weight, twins, and premature delivery. Results In a total of 47,538 newborns, 1,415 were positively identified with deafness gene mutations. The total rate of the deafness gene mutation was 2.976%. The carrier rates of GJB2 (c.35 del G, c.176 del 16, c.235 del C, c.299 del AT, c.155 del TCTG), GJB3 (c.583 C>T), SLC26A4 (c.2168 A>G, c.919-2 A>G, c.1299 C>T), and mtDNA 12S rRNA (m.1555 A>G, m.1494 C>T, m.12201 T>C, m.7445 A>G) mutations were 0.000%, 0.048%, 1.422%, 0.185%, 0.000%, 0.076%, 0.116%, 0.755%, 0.160%, 0.187%, 0.021%, 0.000%, and 0.006%, respectively. Conclusions Our study showed that the c.235 del C GJB2 mutation was the leading deafness-related mutation in the Foshan area of South China. Deafness gene mutations screening in newborns detected by bloodspot-based genetic screening tests can help the diagnosis of newborn congenital hearing loss.
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Affiliation(s)
- Shunwang Cao
- Department of Laboratory Medicine, The Second Clinical College of Guangzhou University of Chinese Medicine, Guangdong, China
| | - Yanhua Sha
- Department of Laboratory Medicine, The Second Clinical College of Guangzhou University of Chinese Medicine, Guangdong, China
| | - Peifeng Ke
- Department of Laboratory Medicine, The Second Clinical College of Guangzhou University of Chinese Medicine, Guangdong, China
| | - Tingting Li
- Department of Laboratory Medicine, The Second Clinical College of Guangzhou University of Chinese Medicine, Guangdong, China
| | - Weixi Yuan
- Foshan Neonate Disease Screening Center, Foshan Maternity and Children's Healthcare Hospital, Guangdong, China
| | - Xianzhang Huang
- Department of Laboratory Medicine, The Second Clinical College of Guangzhou University of Chinese Medicine, Guangdong, China
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19
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Li M, Nishio SY, Naruse C, Riddell M, Sapski S, Katsuno T, Hikita T, Mizapourshafiyi F, Smith FM, Cooper LT, Lee MG, Asano M, Boettger T, Krueger M, Wietelmann A, Graumann J, Day BW, Boyd AW, Offermanns S, Kitajiri SI, Usami SI, Nakayama M. Digenic inheritance of mutations in EPHA2 and SLC26A4 in Pendred syndrome. Nat Commun 2020; 11:1343. [PMID: 32165640 PMCID: PMC7067772 DOI: 10.1038/s41467-020-15198-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 02/17/2020] [Indexed: 01/03/2023] Open
Abstract
Enlarged vestibular aqueduct (EVA) is one of the most commonly identified inner ear malformations in hearing loss patients including Pendred syndrome. While biallelic mutations of the SLC26A4 gene, encoding pendrin, causes non-syndromic hearing loss with EVA or Pendred syndrome, a considerable number of patients appear to carry mono-allelic mutation. This suggests faulty pendrin regulatory machinery results in hearing loss. Here we identify EPHA2 as another causative gene of Pendred syndrome with SLC26A4. EphA2 forms a protein complex with pendrin controlling pendrin localization, which is disrupted in some pathogenic forms of pendrin. Moreover, point mutations leading to amino acid substitution in the EPHA2 gene are identified from patients bearing mono-allelic mutation of SLC26A4. Ephrin-B2 binds to EphA2 triggering internalization with pendrin inducing EphA2 autophosphorylation weakly. The identified EphA2 mutants attenuate ephrin-B2- but not ephrin-A1-induced EphA2 internalization with pendrin. Our results uncover an unexpected role of the Eph/ephrin system in epithelial function. While biallelic mutations of the SLC26A4 gene cause non-syndromic hearing loss with enlarged vestibular aqueducts or Pendred syndrome, a considerable number of patients carry mono-allelic mutations. Here the authors identify EPHA2 as another causative gene of Pendred syndrome with SLC26A4.
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Affiliation(s)
- Mengnan Li
- Laboratory for Cell Polarity and Organogenesis, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.,DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-Universität Marburg, Marburg, Germany
| | - Shin-Ya Nishio
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Chie Naruse
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Meghan Riddell
- Laboratory for Cell Polarity and Organogenesis, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Sabrina Sapski
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Tatsuya Katsuno
- Department of Otolaryngology - Head and Neck Surgery Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takao Hikita
- Laboratory for Cell Polarity and Organogenesis, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Fatemeh Mizapourshafiyi
- Laboratory for Cell Polarity and Organogenesis, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.,DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-Universität Marburg, Marburg, Germany
| | - Fiona M Smith
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Leanne T Cooper
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Min Goo Lee
- Department of Pharmacology, Yonsei University College of Medicine, Seoul, Korea
| | - Masahide Asano
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Thomas Boettger
- Department of Cardiac Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Marcus Krueger
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Astrid Wietelmann
- MRI and µCT Service Group, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Johannes Graumann
- Scientific Service Group Biomolecular Mass Spectrometry Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.,German Centre for Cardiovascular Research (DZHK), Partner Site - Rhine-Main, Berlin, Germany
| | - Bryan W Day
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Andrew W Boyd
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Stefan Offermanns
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Shin-Ichiro Kitajiri
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Shin-Ichi Usami
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Masanori Nakayama
- Laboratory for Cell Polarity and Organogenesis, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany. .,DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-Universität Marburg, Marburg, Germany. .,Kumamoto University International Research Center for Medical Scinece, Kumamoto, Japan.
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20
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Park H, Shin DH, Sim JR, Aum S, Lee MG. IRE1α kinase-mediated unconventional protein secretion rescues misfolded CFTR and pendrin. SCIENCE ADVANCES 2020; 6:eaax9914. [PMID: 32128399 PMCID: PMC7030921 DOI: 10.1126/sciadv.aax9914] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 12/04/2019] [Indexed: 05/02/2023]
Abstract
The most prevalent pathogenic mutations in the CFTR (ΔF508) and SLC26A4/pendrin (p.H723R), which cause cystic fibrosis and congenital hearing loss, respectively, evoke protein misfolding and subsequent defects in their cell surface trafficking. Here, we report that activation of the IRE1α kinase pathway can rescue the cell surface expression of ΔF508-CFTR and p.H723R-pendrin through a Golgi-independent unconventional protein secretion (UPS) route. In mammalian cells, inhibition of IRE1α kinase, but not inhibition of IRE1α endonuclease and the downstream effector XBP1, inhibited CFTR UPS. Treatment with the IRE1α kinase activator, (E)-2-(2-chlorostyryl)-3,5,6-trimethyl-pyrazine (CSTMP), rescued cell surface expression and functional activity of ΔF508-CFTR and p.H723R-pendrin. Treatment with a nontoxic dose of CSTMP to ΔF508-CFTR mice restored CFTR surface expression and CFTR-mediated anion transport in the mouse colon. These findings suggest that UPS activation via IRE1α kinase is a strategy to treat diseases caused by defective cell surface trafficking of membrane proteins, including ΔF508-CFTR and p.H723R-pendrin.
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21
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Wasano K, Takahashi S, Rosenberg SK, Kojima T, Mutai H, Matsunaga T, Ogawa K, Homma K. Systematic quantification of the anion transport function of pendrin (SLC26A4) and its disease-associated variants. Hum Mutat 2020; 41:316-331. [PMID: 31599023 PMCID: PMC6930342 DOI: 10.1002/humu.23930] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/01/2019] [Accepted: 10/03/2019] [Indexed: 01/14/2023]
Abstract
Thanks to the advent of rapid DNA sequencing technology and its prevalence, many disease-associated genetic variants are rapidly identified in many genes from patient samples. However, the subsequent effort to experimentally validate and define their pathological roles is extremely slow. Consequently, the pathogenicity of most disease-associated genetic variants is solely speculated in silico, which is no longer deemed compelling. We developed an experimental approach to efficiently quantify the pathogenic effects of disease-associated genetic variants with a focus on SLC26A4, which is essential for normal inner ear function. Alterations of this gene are associated with both syndromic and nonsyndromic hereditary hearing loss with various degrees of severity. We established HEK293T-based stable cell lines that express pendrin missense variants in a doxycycline-dependent manner, and systematically determined their anion transport activities with high accuracy in a 96-well plate format using a high throughput plate reader. Our doxycycline dosage-dependent transport assay objectively distinguishes missense variants that indeed impair the function of pendrin from those that do not (functional variants). We also found that some of these putative missense variants disrupt normal messenger RNA splicing. Our comprehensive experimental approach helps determine the pathogenicity of each pendrin variant, which should guide future efforts to benefit patients.
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Affiliation(s)
- Koichiro Wasano
- Department of Otolaryngology – Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Laboratory of Auditory Disorders, Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro, Tokyo 152-8902, Japan
| | - Satoe Takahashi
- Department of Otolaryngology – Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Samuel K. Rosenberg
- Department of Otolaryngology – Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Takashi Kojima
- Department of Otolaryngology – Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Hideki Mutai
- Laboratory of Auditory Disorders, Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro, Tokyo 152-8902, Japan
| | - Tatsuo Matsunaga
- Laboratory of Auditory Disorders, Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro, Tokyo 152-8902, Japan
| | - Kaoru Ogawa
- Department of Otolaryngology, Head and Neck Surgery, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Kazuaki Homma
- Department of Otolaryngology – Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- The Hugh Knowles Center for Clinical and Basic Science in Hearing and Its Disorders, Northwestern University, Evanston, IL 60608, USA
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22
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Choi HJ, Lee HJ, Choi JY, Jeon IH, Noh B, Devkota S, Lee HW, Eo SK, Choi JY, Lee MG, Jung J. DNAJC14 Ameliorates Inner Ear Degeneration in the DFNB4 Mouse Model. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2019; 17:188-197. [PMID: 31909090 PMCID: PMC6940655 DOI: 10.1016/j.omtm.2019.11.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 11/23/2019] [Indexed: 01/22/2023]
Abstract
The His723Arg (H723R) mutation in SLC26A4, encoding pendrin, is the most prevalent mutation in East Asia, resulting in DFNB4, an autosomal recessive type of genetic hearing loss. Although the main pathological mechanism of H723R was identified as a protein-folding defect in pendrin, there is still no curative treatment for associated hearing loss. Here, we show that H723R-pendrin expression and activity are rescued by activation of the chaperonin DNAJC14. In vitro, DNAJC14 was activated via Japanese encephalitis virus (JEV) inoculation, and toxin-attenuated JEV rescued the surface expression and anion exchange activity of H723R-pendrin. Human H723R-pendrin transgenic mice (hH723R Tg) were established in a mouse slc26a4 knockout background, in which only hH723R-pendrin was expressed in the inner ear (Pax2-Cre dependent) to mimic human DFNB4 pathology. Crossing hH723R Tg with DNAJC14-overexpressing mice resulted in reduced cochlear hydrops and more preserved outer hair cells in the cochlea compared to those in hH723R Tg mice. Furthermore, the stria vascularis and spiral ligament were thicker and KCNJ10 expression was increased with DNAJC14 overexpression; however, hearing function and enlarged endolymphatic hydrops were not recovered. These results indicate that DNAJC14 overexpression ameliorates the cochlear degeneration caused by misfolded pendrin and might be a potential therapeutic target for DFNB4.
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Affiliation(s)
- Hye Ji Choi
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Hyun Jae Lee
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Jin Young Choi
- Department of Microbiology, College of Veterinary Medicine, Chonbuk National University, Iksan City 54596, Republic of Korea
| | - Ik Hyun Jeon
- Department of Ophthalmology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Byunghwa Noh
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Sushil Devkota
- Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Han-Woong Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Laboratory Animal Research Center, Yonsei University, Seoul 03722, Republic of Korea
| | - Seong Kug Eo
- Department of Microbiology, College of Veterinary Medicine, Chonbuk National University, Iksan City 54596, Republic of Korea
| | - Jae Young Choi
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Min Goo Lee
- Department of Pharmacology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
- Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Jinsei Jung
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
- Corresponding author: Jinsei Jung, Department of Otorhinolaryngology, Yonsei University College of Medicine, 134 Sinchon-dong, Seodaemun-gu, Seoul 120-752, Korea.
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23
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Wen Z, Zhu H, Li Z, Zhang S, Zhang A, Zhang T, Fu X, Sun D, Zhang J, Gao J. A knock-in mouse model of Pendred syndrome with Slc26a4 L236P mutation. Biochem Biophys Res Commun 2019; 515:359-365. [PMID: 31155292 DOI: 10.1016/j.bbrc.2019.05.157] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 05/25/2019] [Indexed: 11/25/2022]
Abstract
SLC26A4 gene mutations lead to Pendred syndrome and non-syndromic hearing loss (DFNB4). The mouse model is well used to study the pathology of Pendred syndrome, however, mice with different Slc26a4 mutations exhibit different phenotypes, and these mice have severe deafness and inner ear malformations that are not imitated less severely Human phenotype. In this study, we generated a knock-in mouse model of Pendred syndrome with Slc26a4 L236P mutation to mimic the most common mutation found in human. Some L236P mice were observed to have significant vestibular dysfunction including torticollis and circling, the giant otoconia and destruction of the otoconial membrane was observed in L236P mice. Unlike other profoundly deafness in Slc26a4 mouse model, L236P mice present mild to profound hearing loss, consistent with the hearing threshold, inner ear hair cells also lost from slight to significant. Together, these data demonstrate that the L236P mouse phenotype is more similar to the human phenotype and should be used as a tool for further research into the human Pendred syndrome.
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Affiliation(s)
- Zongzhuang Wen
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Haixia Zhu
- State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, China
| | - Zhenzu Li
- Department of Bioengineering, Shandong Polytechnic, Jinan, Shandong, China
| | - Sen Zhang
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Aizhen Zhang
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Tingting Zhang
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Xiaolong Fu
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Daqing Sun
- Department of Paediatric Surgery, Tianjin Medical University General Hospital, Tianjin, China.
| | - Jian Zhang
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China.
| | - Jiangang Gao
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China.
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24
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Kim J, Gee HY, Lee MG. Unconventional protein secretion – new insights into the pathogenesis and therapeutic targets of human diseases. J Cell Sci 2018; 131:131/12/jcs213686. [DOI: 10.1242/jcs.213686] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
ABSTRACT
Most secretory proteins travel through a well-documented conventional secretion pathway involving the endoplasmic reticulum (ER) and the Golgi complex. However, recently, it has been shown that a significant number of proteins reach the plasma membrane or extracellular space via unconventional routes. Unconventional protein secretion (UPS) can be divided into two types: (i) the extracellular secretion of cytosolic proteins that do not bear a signal peptide (i.e. leaderless proteins) and (ii) the cell-surface trafficking of signal-peptide-containing transmembrane proteins via a route that bypasses the Golgi. Understanding the UPS pathways is not only important for elucidating the mechanisms of intracellular trafficking pathways but also has important ramifications for human health, because many of the proteins that are unconventionally secreted by mammalian cells and microorganisms are associated with human diseases, ranging from common inflammatory diseases to the lethal genetic disease of cystic fibrosis. Therefore, it is timely and appropriate to summarize and analyze the mechanisms of UPS involvement in disease pathogenesis, as they may be of use for the development of new therapeutic approaches. In this Review, we discuss the intracellular trafficking pathways of UPS cargos, particularly those related to human diseases. We also outline the disease mechanisms and the therapeutic potentials of new strategies for treating UPS-associated diseases.
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Affiliation(s)
- Jiyoon Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Heon Yung Gee
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Min Goo Lee
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
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25
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Yang SM, Liu Y, Liu C, Yin AH, Wu YF, Zheng XE, Yang HM, Yang J. Hearing-loss-associated gene detection in neonatal intensive care unit. J Matern Fetal Neonatal Med 2018; 31:284-288. [PMID: 28093008 DOI: 10.1080/14767058.2017.1282454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To investigate the frequency and mutation spectrum of hearing loss-associated gene mutation in Neonatal Intensive Care Unit (NICU). METHODS Neonates (n=2305) admitted to NICU were enrolled in this study. Nine prominent hearing loss-associated genes, GJB2 (35 del G, 176 del 16,235 del C, 299 del AT), GJB3 (538 C > T), SLC26A4 (IVS7-2A > G, 2168 A > G) and mtDNA 12S rRNA(1555 A > G, 1494 C > T), were detected. RESULT There were 73 cases hearing-loss-associated gene mutation among 2305 cases, the mutation frequency was 3.1%, with 40 cases GJB2 (235del C) mutation (54.8%), 6 cases GJB2 (299 del AT) mutation (8.2%), 21 cases SLC26A4 (IVS 7-2 A > G) mutation (28.7%), 4 cases SLC26A4 (2168 A > G) mutation (5.5%), 2 cases of GJB2 (235del C) combined SLC26A4 (IVS 7-2 A > G, 2168 A > G) mutation (2.8%). Among 73 gene mutation cases, preterm neonates presented in 18 cases, accounting for 24.7% (18/73); hyperbilirubinemia in 13 cases, accounting for 17.8% (13/73); Torch Syndrome in 15 cases, with 12 cases CMV, 2 cases rubella, 1 case toxoplasm, respectively, totally accounting for 20.54% (15/73); neonatal pneumonia in 12 cases, accounting for 16.4% (12/73); birth asphyxia in 5 cases, accounting for 6.9% (5/73); sepsis in 5 cases, accounting for 6.9% (5/73); others in 5 cases, accounting for 6.8% (5/73) . CONCLUSIONS The frequency of hearing loss-associated gene mutation was higher in NICU.There were hearing loss-associated gene mutations in the NICU, suggesting this mutation may complicate with perinatal high-risk factors.
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Affiliation(s)
- S M Yang
- a Department of Neonatology , Guangdong Women and Children Hospital , Guangzhou , China
| | - Ying Liu
- a Department of Neonatology , Guangdong Women and Children Hospital , Guangzhou , China
| | - C Liu
- b Prenatal Diagnosis Centre, Guangdong Women and Children Hospital , Guangzhou , China
| | - A H Yin
- b Prenatal Diagnosis Centre, Guangdong Women and Children Hospital , Guangzhou , China
| | - Y F Wu
- c Department of ENT , Guangdong Women and Children Hospital , Guangzhou , China
| | - X E Zheng
- a Department of Neonatology , Guangdong Women and Children Hospital , Guangzhou , China
| | - H M Yang
- a Department of Neonatology , Guangdong Women and Children Hospital , Guangzhou , China
| | - J Yang
- a Department of Neonatology , Guangdong Women and Children Hospital , Guangzhou , China
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26
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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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Zhu GJ, Shi LS, Zhou H, Yang Y, Chen J, Gao X. A novel compound heterozygous mutation of SLC26A4 in two Chinese families with nonsyndromic hearing loss and enlarged vestibular aqueducts. Mol Med Rep 2017; 16:9011-9016. [PMID: 28990112 DOI: 10.3892/mmr.2017.7690] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 08/10/2017] [Indexed: 11/06/2022] Open
Abstract
Enlarged vestibular aqueduct (EVA)‑associated hearing loss is frequently detected in individuals carrying the SLC26A4 mutation in the Chinese population. The present study aimed to identify the causative SLC26A4 coding mutations in a patient group with nonsyndromic hearing loss (NSHL) and EVA. Genomic DNA was extracted from blood samples obtained from 52 NSHL patients with EVA and from 60 normal controls. The mutation analysis for 20 coding exons of SLC26A4 was performed by direct sequencing. The results of the mutational analysis showed that there were two probands from two separate families suffering from bilateral sensorineural hearing loss with EVA, carrying the same novel compound heterozygous mutation of SLC26A4 (c.1644_1645insA and c.2168A>G). Other members of the two families had heterozygous mono‑allelic mutations with normal hearing. However, neither of these mutations were detected in the 60 normal controls. These results are the first, to the best of our knowledge, to link the compound heterozygote mutation, c.1644_1645insA and c.2168A>G, in the SLC26A4 gene to NSHL patients with EVA. The two mutations identified in the present study were located in the anti‑sigma factor antagonist domain, the core region for plasma membrane targeting of anion transporters, which suggested that the reduced or complete loss of SLC26A4 function was the direct cause of hearing loss in the two patients. These results provide a foundation for further elucidating the genetic factors responsible for EVA‑associated NSHL.
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Affiliation(s)
- Guang-Jie Zhu
- Department of Otorhinolaryngology, Head and Neck Surgery, Drum Tower Hospital Affiliated to Nanjing University Medical School, Nanjing, Jiangsu 210008, P.R. China
| | - Lu-Sen Shi
- Department of Otorhinolaryngology, Head and Neck Surgery, Drum Tower Hospital Affiliated to Nanjing University Medical School, Nanjing, Jiangsu 210008, P.R. China
| | - Han Zhou
- Department of Otorhinolaryngology, Head and Neck Surgery, Drum Tower Hospital Affiliated to Nanjing University Medical School, Nanjing, Jiangsu 210008, P.R. China
| | - Ye Yang
- Department of Otorhinolaryngology, Head and Neck Surgery, Drum Tower Hospital Affiliated to Nanjing University Medical School, Nanjing, Jiangsu 210008, P.R. China
| | - Jie Chen
- Department of Otorhinolaryngology, Head and Neck Surgery, Drum Tower Hospital Affiliated to Nanjing University Medical School, Nanjing, Jiangsu 210008, P.R. China
| | - Xia Gao
- Department of Otorhinolaryngology, Head and Neck Surgery, Drum Tower Hospital Affiliated to Nanjing University Medical School, Nanjing, Jiangsu 210008, P.R. China
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Aimoni C, Ciorba A, Cerritelli L, Ceruti S, Skarżyński PH, Hatzopoulos S. Enlarged vestibular aqueduct: Audiological and genetical features in children and adolescents. Int J Pediatr Otorhinolaryngol 2017; 101:254-258. [PMID: 28780189 DOI: 10.1016/j.ijporl.2017.07.042] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/19/2017] [Accepted: 07/25/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND Enlarged Vestibular Aqueduct (EVA) is one of the most common congenital malformations associated with sensorineural or mixed hearing loss. The association between hearing loss and EVA is described in syndromic (i.e. Pendred Syndrome, BOR, Waardenburg) and non-syndromic disorders, as isolate or familiar mutations of the SLC26A4 gene. The audiological phenotype of the EVA syndrome is heterogeneous, the type and entity of hearing loss may vary and vertigo episodes might also be present. OBJECTIVE The aim of this retrospective study was to describe the clinical and genetic features of a group of adolescent subjects presenting an EVA clinical profile, considering the presence of SLC26A4 gene mutations. METHODS 14 Caucasian patients were assessed (24 ears in total; 4 patients presented a monolateral EVA), 10 females and 4 males. Their age at the time of diagnosis was between 1 and 6 years (mean age 2.5 years). Subjects were assessed by an ENT microscopy evaluation with a complete audiometric assessment, CT & MRI scans and genetic tests for the evaluation of the pendrin gene mutations (SLC26A4). RESULTS Considering the presence of SLC26A4 mutations and thyroid function, we could identify three sub-groups of patients: group 1, non syndromic EVA (ns EVA, no SLC26A4 mutation and no thyroid dysfunction); group 2, EVA with DFNB4 (single SLC26A4 gene mutation and no thyroid dysfunction); group 3, EVA with Pendred Syndrome (two pathological mutation of SLC26A4 and thyromegaly with thyroid dysfunction). Patients of group 1 (ns-EVA) showed various degrees of hearing loss from mild (55%) to severe-profound (45%). In groups 2 (DFNB4) and 3 (PDS), the degree of hearing loss is severe to profound in 70-75% of the cases; middle and high frequencies are mainly involved. CONCLUSIONS The phenotypic expressions associated with the EVA clinical profile are heterogeneous. From the available data, it was not possible to identify a representative audiological profile, in any of the three sub-groups. The data suggest that: (i) a later onset of hearing loss is usually related to EVA, in absence of SLC26A4 gene mutations; and (ii) hearing loss is more severe in patients with SLC26A4 gene mutations (groups 2 and 3 of this study).
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Affiliation(s)
- C Aimoni
- Clinic of Audiology & ENT, University of Ferrara, Italy
| | - A Ciorba
- Clinic of Audiology & ENT, University of Ferrara, Italy.
| | - L Cerritelli
- Clinic of Audiology & ENT, University of Ferrara, Italy
| | - S Ceruti
- Neuroradiology Department, University Hospital of Ferrara, Italy
| | - P H Skarżyński
- Institute of Physiology and Pathology of Hearing, Warsaw, Kajetany, Poland; World Hearing Center, Warsaw, Poland; Department of Heart Failure and Cardiac Rehabilitation, Medical University of Warsaw, Warsaw, Poland; Institute of Sensory Organs, Kajetany, Poland
| | - S Hatzopoulos
- Clinic of Audiology & ENT, University of Ferrara, Italy
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Rapp C, Bai X, Reithmeier RAF. Molecular analysis of human solute carrier SLC26 anion transporter disease-causing mutations using 3-dimensional homology modeling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:2420-2434. [PMID: 28941661 DOI: 10.1016/j.bbamem.2017.09.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 06/08/2017] [Accepted: 09/14/2017] [Indexed: 12/22/2022]
Abstract
The availability of the first crystal structure of a bacterial member (SLC26Dg) of the solute carrier SLC26 family of anion transporters has allowed us to create 3-dimensional models of all 10 human members (SLC26A1-A11, A10 being a pseudogene) of these membrane proteins using the Phyre2 bioinformatic tool. The homology modeling predicted that the SLC26 human proteins, like the SLC26Dg template, all consist of 14 transmembrane segments (TM) arranged in a 7+7 inverted topology with the amino-termini of two half-helices (TM3 and 10) facing each other in the centre of the protein to create the anion-binding site, linked to a C-terminal cytosolic sulfate transporter anti-sigma factor antagonist (STAS) domain. A plethora of human diseases are associated with mutations in the genes encoding human SLC26 transporters, including chondrodysplasias with varying severity in SLC26A2 (~50 mutations, 27 point mutations), congenital chloride-losing diarrhea in SLC26A3 (~70 mutations, 31 point mutations) and Pendred Syndrome or deafness autosomal recessive type 4 in SLC26A4 (~500 mutations, 203 point mutations). We have localized all of these point mutations in the 3-dimensional structures of the respective SLC26A2, A3 and A4 proteins and systematically analyzed their effect on protein structure. While most disease-causing mutations may cause folding defects resulting in impaired trafficking of these membrane glycoproteins from the endoplasmic reticulum to the cell surface - as demonstrated in a number of functional expression studies - the modeling also revealed that a number of pathogenic mutations are localized to the anion-binding site, which may directly affect transport function.
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Affiliation(s)
- Chloe Rapp
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Xiaoyun Bai
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Rives ML, Javitch JA, Wickenden AD. Potentiating SLC transporter activity: Emerging drug discovery opportunities. Biochem Pharmacol 2017; 135:1-11. [DOI: 10.1016/j.bcp.2017.02.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 02/13/2017] [Indexed: 12/12/2022]
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Kallel-Bouattour R, Belguith-Maalej S, Zouari-Bradai E, Mnif M, Abid M, Hadj Kacem H. Intronic variants of SLC26A4 gene enhance splicing efficiency in hybrid minigene assay. Gene 2017; 620:10-14. [PMID: 28389359 DOI: 10.1016/j.gene.2017.03.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 03/19/2017] [Accepted: 03/31/2017] [Indexed: 12/14/2022]
Abstract
The SLC26A4 genomic sequence screening in autoimmune thyroid diseases (AITD) revealed different variants types with possible pathogenic effects. Although intronic variants may have more detrimental effects than those coding, they are poorly explored. Thus, in a first assessment, our bioinformatics analysis of intronic variants predicted a pathogenic effect of c.1002-9A>C, c.1545-5T>G and c.1544+9C>T variants. Validating these variants pathogenicity may provide new clues on the AITD physiopathology. Variants were explored in a general population by PCR-RFLP. These variants effects on the mRNA processing was assessed using functional splicing assay based in DNA hybrid minigene in HeLa cell lines. The constructs splicing efficiency was investigated by real time PCR. Our results revealed that c.1002-9A>C is a rare allele (minor frequency allele (MFA)=0.007) whereas c.1545-5T>G and c.1544+9C>T are low frequency variants. The RT-PCR analysis showed that these variants did not affect the mRNA processing. However, quantifying the transcripts generated from minigene constructs proved an mRNA splicing enhancement. Our study suggests a pathogenic effect of three intronic variants on the mRNA splicing efficiency using a DNA Hybrid minigene. By quantifying these transcripts, we unveil the limit of standard RT-PCR in analyzing a splicing minigene assay.
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Affiliation(s)
- Rihab Kallel-Bouattour
- Laboratoire Procédés de Criblage Moléculaire et Cellulaire, Centre Biotechnologie de Sfax, Tunisia
| | - Salima Belguith-Maalej
- Laboratoire Procédés de Criblage Moléculaire et Cellulaire, Centre Biotechnologie de Sfax, Tunisia
| | - Emna Zouari-Bradai
- Laboratoire Procédés de Criblage Moléculaire et Cellulaire, Centre Biotechnologie de Sfax, Tunisia
| | - Mouna Mnif
- Service d'Endocrinologie, CHU, Hédi Chaker, Sfax, Tunisia
| | - Mohamed Abid
- Service d'Endocrinologie, CHU, Hédi Chaker, Sfax, Tunisia
| | - Hassen Hadj Kacem
- Laboratoire Procédés de Criblage Moléculaire et Cellulaire, Centre Biotechnologie de Sfax, Tunisia; Department of Applied Biology, College of Sciences, University of Sharjah, United Arab Emirates.
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Abstract
Mutations in gap junction proteins encoding beta connexions are believed to be a major cause for congenital hearing loss. The purpose of this study was to do comparative analyses of frequencies of most prominent mutations responsible for congenital deafness. Using fluorescence PCR method, the entire coding region of GJB2 gene, GJB3 gene, and SLC26A4 was analyzed. Direct DNA sequencing was used to analyze mutations in these genes among unrelated 2,674 cases of newborns. Also, 12S rRNA mutation was also studied in these cases. In 2,674 cases of newborns from June 2013 to June 2014, found deafness mutation in 137 cases (5.12 % of carrier rate), carrying GJB2 mutations in 68 cases (2.54 % of carry rate), GJB3 mutations in 10 cases (0.37 % of carry rate), SLC26A4 mutations in 54 cases (2.02 % of carry rate), and mitochondrial 12S rRNA mutations in five cases (0.19 % of carry rate). The study concludes that GJB2 gene mutation is the most common and mitochondrial 12S rRNA mutations are the least common mutation for congenital hearing loss in Chinese newborns.
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Mapping pathogenic mutations suggests an innovative structural model for the pendrin (SLC26A4) transmembrane domain. Biochimie 2016; 132:109-120. [PMID: 27771369 DOI: 10.1016/j.biochi.2016.10.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 10/03/2016] [Indexed: 12/16/2022]
Abstract
Human pendrin (SLC26A4) is an anion transporter mostly expressed in the inner ear, thyroid and kidney. SLC26A4 gene mutations are associated with a broad phenotypic spectrum, including Pendred Syndrome and non-syndromic hearing loss with enlarged vestibular aqueduct (ns-EVA). No experimental structure of pendrin is currently available, making phenotype-genotype correlations difficult as predictions of transmembrane (TM) segments vary in number. Here, we propose a novel three-dimensional (3D) pendrin transmembrane domain model based on the SLC26Dg transporter. The resulting 14 TM topology was found to include two non-canonical transmembrane segments crucial for pendrin activity. Mutation mapping of 147 clinically validated pathological mutations shows that most affect two previously undescribed TM regions.
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Mateo Sánchez S, Freeman SD, Delacroix L, Malgrange B. The role of post-translational modifications in hearing and deafness. Cell Mol Life Sci 2016; 73:3521-33. [PMID: 27147466 PMCID: PMC11108544 DOI: 10.1007/s00018-016-2257-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 04/21/2016] [Accepted: 04/26/2016] [Indexed: 12/20/2022]
Abstract
Post-translational modifications (PTMs) are key molecular events that modify proteins after their synthesis and modulate their ultimate functional properties by affecting their stability, localisation, interaction potential or activity. These chemical changes expand the size of the proteome adding diversity to the molecular pathways governing the biological outcome of cells. PTMs are, thus, crucial in regulating a variety of cellular processes such as apoptosis, proliferation and differentiation and have been shown to be instrumental during embryonic development. In addition, alterations in protein PTMs have been implicated in the pathogenesis of many human diseases, including deafness. In this review, we summarize the recent progress made in understanding the roles of PTMs during cochlear development, with particular emphasis on the enzymes driving protein phosphorylation, acetylation, methylation, glycosylation, ubiquitination and SUMOylation. We also discuss how these enzymes may contribute to hearing impairment and deafness.
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Affiliation(s)
- Susana Mateo Sánchez
- Developmental Neurobiology Unit, GIGA-Neurosciences, University of Liège, Quartier Hôpital (CHU), Avenue Hippocrate 15, Tour 4, 1er étage, Bât. B36, 4000, Liège, Belgium
| | - Stephen D Freeman
- Developmental Neurobiology Unit, GIGA-Neurosciences, University of Liège, Quartier Hôpital (CHU), Avenue Hippocrate 15, Tour 4, 1er étage, Bât. B36, 4000, Liège, Belgium
| | - Laurence Delacroix
- Developmental Neurobiology Unit, GIGA-Neurosciences, University of Liège, Quartier Hôpital (CHU), Avenue Hippocrate 15, Tour 4, 1er étage, Bât. B36, 4000, Liège, Belgium
| | - Brigitte Malgrange
- Developmental Neurobiology Unit, GIGA-Neurosciences, University of Liège, Quartier Hôpital (CHU), Avenue Hippocrate 15, Tour 4, 1er étage, Bât. B36, 4000, Liège, Belgium.
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35
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Sagong B, Baek JI, Lee KY, Kim UK. A Novel Frameshift Mutation of SLC26A4 in a Korean Family With Nonsyndromic Hearing Loss and Enlarged Vestibular Aqueduct. Clin Exp Otorhinolaryngol 2016; 10:50-55. [PMID: 27384033 PMCID: PMC5327591 DOI: 10.21053/ceo.2016.00430] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/22/2016] [Accepted: 05/26/2016] [Indexed: 11/23/2022] Open
Abstract
Objectives We aimed to identify the causative mutation for siblings in a Korean family with nonsyndromic hearing loss (HL) and enlarged vestibular aqueduct (EVA). The siblings were a 19-year-old female with bilateral profound HL and an 11-year-old male with bilateral moderately severe HL. Methods We extracted genomic DNA from blood samples of the siblings with HL, their parents, and 100 controls. We performed mutation analysis for SLC26A4 using direct sequencing. Results The two siblings were compound heterozygotes with the novel mutation p.I713LfsX8 and the previously described mutation p.H723R. Their parents had heterozygous mono-allelic mutations. Father had p.I713LfsX8 mutation as heterozygous, and mother had p.H723R mutation as heterozygous. However, novel mutation p.I713LfsX8 was not detected in 100 unrelated controls. Conclusion Both mutations identified in this study were located in the sulfate transporter and anti-sigma factor antagonist domain, the core region for membrane targeting of SulP/SLC26 anion transporters, which strongly suggests that failure in membrane trafficking by SLC26A4 is a direct cause of HL in this family. Our study could therefore provide a foundation for further investigations elucidating the SLC26A4-related mechanisms of HL.
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Affiliation(s)
- Borum Sagong
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, Korea
| | - Jeong-In Baek
- Department of Aroma Applied Industry, College of Herbal Bio-Industry, Daegu Haany University, Gyeongsan, Korea
| | - Kyu-Yup Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Kyungpook National University School of Medicine, Daegu, Korea
| | - Un-Kyung Kim
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, Korea.,School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea
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36
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The HSP70 co-chaperone DNAJC14 targets misfolded pendrin for unconventional protein secretion. Nat Commun 2016; 7:11386. [PMID: 27109633 PMCID: PMC4848490 DOI: 10.1038/ncomms11386] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 03/18/2016] [Indexed: 12/19/2022] Open
Abstract
Mutations in SLC26A4, which encodes pendrin, are responsible for hearing loss with an enlarged vestibular aqueduct and Pendred syndrome. The most prevalent mutation in East Asia is p.H723R (His723Arg), which leads to defects in protein folding and cell-surface expression. Here we show that H723R-pendrin can be rescued to the cell surface by an HSP70 co-chaperone DNAJC14-dependent unconventional trafficking pathway. Blockade of ER-to-Golgi transport or activation of ER stress signals induced Golgi-independent cell-surface expression of H723R-pendrin and restored its cell-surface Cl−/HCO3− exchange activity. Proteomic and short interfering RNA screenings with subsequent molecular analyses showed that Hsc70 and DNAJC14 are required for the unconventional trafficking of H723R-pendrin. Moreover, DNAJC14 upregulation was able to induce the unconventional cell-surface expression of H723R-pendrin. These results indicate that Hsc70 and DNAJC14 play central roles in ER stress-associated unconventional protein secretion and are potential therapeutic targets for diseases such as Pendred syndrome, which arise from transport defects of misfolded proteins. Mutations in pendrin, a plasma membrane transporter, lead to Pendred syndrome, which is associated with hearing loss. Here, Jung et al. show that cell-surface expression of a mutated form of pendrin can be restored by blocking ER-to-Golgi traffic and triggering a DNAJC14 dependent unconventional secretion pathway.
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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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Lee HJ, Yoo JE, Namkung W, Cho HJ, Kim K, Kang JW, Yoon JH, Choi JY. Thick airway surface liquid volume and weak mucin expression in pendrin-deficient human airway epithelia. Physiol Rep 2015; 3:3/8/e12480. [PMID: 26243215 PMCID: PMC4562566 DOI: 10.14814/phy2.12480] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Pendrin is an anion exchanger whose mutations are known to cause hearing loss. However, recent data support the linkage between pendrin expression and airway diseases, such as asthma. To evaluate the role of pendrin in the regulation of the airway surface liquid (ASL) volume and mucin expression, we investigated the function and expression of pendrin and ion channels and anion exchangers. Human nasal epithelial cells were cultured from 16 deaf patients carrying pendrin mutations (DFNB4) and 17 controls. The cells were treated with IL-13 to induce mucus hypersecretion. Airway surface liquid thickness was measured and real-time polymerase chain reaction was performed targeting various transporters and MUC5AC. Anion exchanger activity was measured using a pH-sensitive fluorescent probe. Periodic acid-Schiff staining was performed on the cultured cells and inferior turbinate tissues. The ASL layer of the nasal epithelia from DFNB4 subjects was thicker than the controls, and the difference became more prominent following IL-13 stimulation. There was no difference in anion exchange activity after IL-13 treatment in the cells from DFNB4 patients, while it increased in the controls. Goblet cell metaplasia induced by IL-13 treatment seen in the controls was not observed in the DFNB4 cells. Furthermore, the periodic acid-Schiff staining-positive area was lesser in the inferior turbinate tissues from DFNB4 patients that those from controls. Pendrin plays a critical role in ASL volume regulation and mucin expression as pendrin-deficient airway epithelial cells are refractory to stimulation with IL-13. Specific blockers targeting pendrin in the airways may therefore have therapeutic potential in the treatment of allergic airway diseases.
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Affiliation(s)
- Hyun Jae Lee
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea Research Center for Human Natural Defense System, Yonsei University, Seoul, Korea Department of Otorhinolaryngology, Yonsei University, Seoul, Korea
| | - Jee Eun Yoo
- Research Center for Human Natural Defense System, Yonsei University, Seoul, Korea Department of Otorhinolaryngology, Yonsei University, Seoul, Korea
| | - Wan Namkung
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences Yonsei University, Incheon, Korea
| | - Hyung-Ju Cho
- Department of Otorhinolaryngology, Yonsei University, Seoul, Korea Airway Mucus Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Kyubo Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea
| | - Joo Wan Kang
- Airway Mucus Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Joo-Heon Yoon
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea Research Center for Human Natural Defense System, Yonsei University, Seoul, Korea Department of Otorhinolaryngology, Yonsei University, Seoul, Korea Airway Mucus Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Jae Young Choi
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea Research Center for Human Natural Defense System, Yonsei University, Seoul, Korea Department of Otorhinolaryngology, Yonsei University, Seoul, Korea Airway Mucus Institute, Yonsei University College of Medicine, Seoul, Korea
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Yao J, Qian X, Bao J, Wei Q, Lu Y, Zheng H, Cao X, Xing G. Probing the Effect of Two Heterozygous Mutations in Codon 723 of SLC26A4 on Deafness Phenotype Based on Molecular Dynamics Simulations. Sci Rep 2015; 5:10831. [PMID: 26035154 PMCID: PMC4451684 DOI: 10.1038/srep10831] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 04/27/2015] [Indexed: 11/09/2022] Open
Abstract
A Chinese family was identified with clinical features of enlarged vestibular aqueduct syndrome (EVAS). The mutational analysis showed that the proband (III-2) had EVAS with bilateral sensorineural hearing loss and carried a rare compound heterozygous mutation of SLC26A4 (IVS7-2A>G, c.2167C>G), which was inherited from the same mutant alleles of IVS7-2A>G heterozygous father and c.2167C>G heterozygous mother. Compared with another confirmed pathogenic biallelic mutation in SLC26A4 (IVS7-2A>G, c.2168A>G), these two biallelic mutations shared one common mutant allele and the same codon of the other mutant allele, but led to different changes of amino acid (p.H723D, p.H723R) and both resulted in the deafness phenotype. Structure-modeling indicated that these two mutant alleles changed the shape of pendrin protein encoded by SLC26A4 with increasing randomness in conformation, and might impair pendrin’s ability as an anion transporter. The molecular dynamics simulations also revealed that the stability of mutant pendrins was reduced with increased flexibility of backbone atoms, which was consistent with the structure-modeling results. These evidences indicated that codon 723 was a hot-spot region in SLC26A4 with a significant impact on the structure and function of pendrin, and acted as one of the genetic factors responsible for the development of hearing loss.
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Affiliation(s)
- Jun Yao
- Department of Biotechnology, School of Basic Medical Science, Nanjing Medical University, Nanjing, P.R. China
| | - Xuli Qian
- Department of Biotechnology, School of Basic Medical Science, Nanjing Medical University, Nanjing, P.R. China
| | - Jingxiao Bao
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, P.R. China
| | - Qinjun Wei
- Department of Biotechnology, School of Basic Medical Science, Nanjing Medical University, Nanjing, P.R. China
| | - Yajie Lu
- Department of Biotechnology, School of Basic Medical Science, Nanjing Medical University, Nanjing, P.R. China
| | - Heng Zheng
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, P.R. China
| | - Xin Cao
- Department of Biotechnology, School of Basic Medical Science, Nanjing Medical University, Nanjing, P.R. China
| | - Guangqian Xing
- Department of Otolaryngology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China
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Soh LM, Druce M, Grossman AB, Differ AM, Rajput L, Bitner-Glindzicz M, Korbonits M. Evaluation of genotype-phenotype relationships in patients referred for endocrine assessment in suspected Pendred syndrome. Eur J Endocrinol 2015; 172:217-26. [PMID: 25394566 DOI: 10.1530/eje-14-0679] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
DESIGN Patients with Pendred syndrome have genotypic and phenotypic variability, leading to challenges in definitive diagnosis. Deaf children with enlarged vestibular aqueducts are often subjected to repeated investigations when tests for mutations in SLC26A4 are abnormal. This study provides genotype and phenotype information from patients with suspected Pendred syndrome referred to a single clinical endocrinology unit. METHODS A retrospective analysis of 50 patients with suspected Pendred syndrome to investigate the correlation between genetic, perchlorate discharge test (PDT) and endocrine status. RESULTS Eight patients with monoallelic SLC26A4 mutations had normal PDT. Of the 33 patients with biallelic mutations, ten of 12 patients with >30% discharge developed hypothyroidism. In our cohort, c.626G>T and c.3-2A>G result in milder clinical presentations with lower median perchlorate discharge of 9.3% (interquartile range 4-15%) compared with 40% (interquartile range 21-60%) for the remaining mutations. Eight novel mutations were detected. All patients with PDT <30% remained euthyroid to date, although the majority are still under the age of 30. There was a significant correlation between PDT and goitre size (R=0.61, P=0.0009) and the age of onset of hypothyroidism (R=-0.62, P=0.0297). In our population, the hazard of becoming hypothyroid increased by 7% per percentage point increase in PDT (P<0.001). CONCLUSION There is a correlation between SLC26A4 genotype and thyroid phenotype. If results hold true for larger patient numbers and longer follow-up, then for patients with monoallelic mutations, PDT could be unnecessary. Patients with biallelic mutations and PDT discharge >30% have a high risk of developing goitre and hypothyroidism, and should have lifelong monitoring.
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Affiliation(s)
- Lip Min Soh
- Department of EndocrinologyBarts and the London School of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UKOxford Centre for DiabetesEndocrinology and Metabolism, University of Oxford, Oxford, UKNorth East Thames Regional Genetics Service LaboratoryDepartment of Audiovestibular MedicineGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UKClinical and Molecular Genetics UnitUCL Institute of Child Health, London WC1N 1EH, UKClinical Genetics UnitGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Maralyn Druce
- Department of EndocrinologyBarts and the London School of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UKOxford Centre for DiabetesEndocrinology and Metabolism, University of Oxford, Oxford, UKNorth East Thames Regional Genetics Service LaboratoryDepartment of Audiovestibular MedicineGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UKClinical and Molecular Genetics UnitUCL Institute of Child Health, London WC1N 1EH, UKClinical Genetics UnitGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Ashley B Grossman
- Department of EndocrinologyBarts and the London School of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UKOxford Centre for DiabetesEndocrinology and Metabolism, University of Oxford, Oxford, UKNorth East Thames Regional Genetics Service LaboratoryDepartment of Audiovestibular MedicineGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UKClinical and Molecular Genetics UnitUCL Institute of Child Health, London WC1N 1EH, UKClinical Genetics UnitGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK Department of EndocrinologyBarts and the London School of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UKOxford Centre for DiabetesEndocrinology and Metabolism, University of Oxford, Oxford, UKNorth East Thames Regional Genetics Service LaboratoryDepartment of Audiovestibular MedicineGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UKClinical and Molecular Genetics UnitUCL Institute of Child Health, London WC1N 1EH, UKClinical Genetics UnitGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Ann-Marie Differ
- Department of EndocrinologyBarts and the London School of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UKOxford Centre for DiabetesEndocrinology and Metabolism, University of Oxford, Oxford, UKNorth East Thames Regional Genetics Service LaboratoryDepartment of Audiovestibular MedicineGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UKClinical and Molecular Genetics UnitUCL Institute of Child Health, London WC1N 1EH, UKClinical Genetics UnitGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Liala Rajput
- Department of EndocrinologyBarts and the London School of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UKOxford Centre for DiabetesEndocrinology and Metabolism, University of Oxford, Oxford, UKNorth East Thames Regional Genetics Service LaboratoryDepartment of Audiovestibular MedicineGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UKClinical and Molecular Genetics UnitUCL Institute of Child Health, London WC1N 1EH, UKClinical Genetics UnitGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Maria Bitner-Glindzicz
- Department of EndocrinologyBarts and the London School of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UKOxford Centre for DiabetesEndocrinology and Metabolism, University of Oxford, Oxford, UKNorth East Thames Regional Genetics Service LaboratoryDepartment of Audiovestibular MedicineGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UKClinical and Molecular Genetics UnitUCL Institute of Child Health, London WC1N 1EH, UKClinical Genetics UnitGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK Department of EndocrinologyBarts and the London School of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UKOxford Centre for DiabetesEndocrinology and Metabolism, University of Oxford, Oxford, UKNorth East Thames Regional Genetics Service LaboratoryDepartment of Audiovestibular MedicineGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UKClinical and Molecular Genetics UnitUCL Institute of Child Health, London WC1N 1EH, UKClinical Genetics UnitGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Márta Korbonits
- Department of EndocrinologyBarts and the London School of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UKOxford Centre for DiabetesEndocrinology and Metabolism, University of Oxford, Oxford, UKNorth East Thames Regional Genetics Service LaboratoryDepartment of Audiovestibular MedicineGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UKClinical and Molecular Genetics UnitUCL Institute of Child Health, London WC1N 1EH, UKClinical Genetics UnitGreat Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
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Jang JH, Jung J, Kim AR, Cho YM, Kim MY, Lee SY, Choi JY, Lee JH, Choi BY. Identification of Novel Functional Null Allele of SLC26A4 Associated with Enlarged Vestibular Aqueduct and Its Possible Implication. Audiol Neurootol 2014; 19:319-26. [DOI: 10.1159/000366190] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 07/28/2014] [Indexed: 11/19/2022] Open
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Alka K, Casey JR. Bicarbonate transport in health and disease. IUBMB Life 2014; 66:596-615. [PMID: 25270914 DOI: 10.1002/iub.1315] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/10/2014] [Indexed: 12/28/2022]
Abstract
Bicarbonate (HCO3(-)) has a central place in human physiology as the waste product of mitochondrial energy production and for its role in pH buffering throughout the body. Because bicarbonate is impermeable to membranes, bicarbonate transport proteins are necessary to enable control of bicarbonate levels across membranes. In humans, 14 bicarbonate transport proteins, members of the SLC4 and SLC26 families, function by differing transport mechanisms. In addition, some anion channels and ZIP metal transporters contribute to bicarbonate movement across membranes. Defective bicarbonate transport leads to diseases, including systemic acidosis, brain dysfunction, kidney stones, and hypertension. Altered expression levels of bicarbonate transporters in patients with breast, colon, and lung cancer suggest an important role of these transporters in cancer.
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Affiliation(s)
- Kumari Alka
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
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Atrophic thyroid follicles and inner ear defects reminiscent of cochlear hypothyroidism in Slc26a4-related deafness. Mamm Genome 2014; 25:304-16. [PMID: 24760582 DOI: 10.1007/s00335-014-9515-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 04/03/2014] [Indexed: 01/10/2023]
Abstract
Thyroid hormone is essential for inner ear development and is required for auditory system maturation. Human mutations in SLC26A4 lead to a syndromic form of deafness with enlargement of the thyroid gland (Pendred syndrome) and non-syndromic deafness (DFNB4). We describe mice with an Slc26a4 mutation, Slc26a4 (loop/loop) , which are profoundly deaf but show a normal sized thyroid gland, mimicking non-syndromic clinical signs. Histological analysis of the thyroid gland revealed defective morphology, with a majority of atrophic microfollicles, while measurable thyroid hormone in blood serum was within the normal range. Characterization of the inner ear showed a spectrum of morphological and molecular defects consistent with inner ear pathology, as seen in hypothyroidism or disrupted thyroid hormone action. The pathological inner ear hallmarks included thicker tectorial membrane with reduced β-tectorin protein expression, the absence of BK channel expression of inner hair cells, and reduced inner ear bone calcification. Our study demonstrates that deafness in Slc26a4 (loop/loop) mice correlates with thyroid pathology, postulating that sub-clinical thyroid morphological defects may be present in some DFNB4 individuals with a normal sized thyroid gland. We propose that insufficient availability of thyroid hormone during inner ear development plays an important role in the mechanism underlying deafness as a result of SLC26A4 mutations.
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Li J, Xia F, Reithmeier RAF. N-glycosylation and topology of the human SLC26 family of anion transport membrane proteins. Am J Physiol Cell Physiol 2014; 306:C943-60. [PMID: 24647542 DOI: 10.1152/ajpcell.00030.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The human solute carrier (SLC26) family of anion transporters consists of 10 members (SLCA1-11, SLCA10 being a pseudogene) that encode membrane proteins containing ~12 transmembrane (TM) segments with putative N-glycosylation sites (-NXS/T-) in extracellular loops and a COOH-terminal cytosolic STAS domain. All 10 members of the human SLC26 family, FLAG-tagged at the NH2 terminus, were transiently expressed in HEK-293 cells. While most proteins were observed to contain both high-mannose and complex oligosaccharides, SLC26A2 was mainly in the complex form, SLC26A4 in the high-mannose form, and SLC26A8 was not N-glycosylated. Mutation of the putative N-glycosylation sites showed that most members contain multiple N-glycosylation sites in the second extracytosolic (EC) loop, except SLC26A11, which was N-glycosylated in EC loop 4. Immunofluorescence staining of permeabilized cells localized the proteins to the plasma membrane and the endoplasmic reticulum, with SLC26A2 highly localized to the plasma membrane. N-glycosylation was not a necessary requirement for cell surface expression as the localization of nonglycosylated proteins was similar to their wild-type counterparts, although a lower level of cell-surface biotinylation was observed. No immunostaining of intact cells was observed for any SLC26 members, demonstrating that the NH2-terminal FLAG tag was located in the cytosol. Topological models of the SLC26 proteins that contain an even number of transmembrane segments with both the NH2 and COOH termini located in the cytosol and utilized N-glycosylation sites defining the positions of two EC loops are presented.
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Affiliation(s)
- Jing Li
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Fan Xia
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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Mutation spectrum and genotype-phenotype correlation of hearing loss patients caused by SLC26A4 mutations in the Japanese: a large cohort study. J Hum Genet 2014; 59:262-8. [PMID: 24599119 PMCID: PMC4521295 DOI: 10.1038/jhg.2014.12] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 12/29/2013] [Accepted: 01/05/2014] [Indexed: 11/08/2022]
Abstract
Mutations in SLC26A4 cause a broad phenotypic spectrum, from typical Pendred syndrome to nonsyndromic hearing loss associated with enlarged vestibular aqueduct. Identification of these mutations is important for accurate diagnosis, proper medical management and appropriate genetic counseling and requires updated information regarding spectrum, clinical characteristics and genotype-phenotype correlations, based on a large cohort. In 100 patients with bilateral enlarged vestibular aqueduct among 1511 Japanese hearing loss probands registered in our gene bank, goiter data were available for 79, of whom 15 had Pendred syndrome and 64 had nonsyndromic hearing loss. We clarified the mutation spectrum for the SLC26A4 mutations and also summarized hearing levels, progression, fluctuation and existence of genotype-phenotype correlation. SLC26A4 mutations were identified in 82 of the 100 patients (82.0%). Of the Pendred syndrome patients, 93% (14/15) were carriers, as were 77% (49/64) of the nonsyndromic hearing loss patients. Clinical characteristics of patients with SLC26A4 mutations were congenital, fluctuating and progressive hearing loss usually associated with vertigo and/or goiter. We found no genotype-phenotype correlations, indicating that, unlike in the case of GJB2 mutations, the phenotype cannot be predicted from the genotype. Our mutation analysis confirmed the importance of mutations in the SLC26A4 gene among hearing loss patients with enlarged vestibular aqueduct and revealed the mutation spectrum, essential information when performing genetic testing.
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Cordat E, Reithmeier RA. Structure, Function, and Trafficking of SLC4 and SLC26 Anion Transporters. CURRENT TOPICS IN MEMBRANES 2014; 73:1-67. [DOI: 10.1016/b978-0-12-800223-0.00001-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Lee H, Jung J, Shin J, Song M, Kim S, Lee JH, Lee KA, Shin S, Kim UK, Bok J, Lee KY, Choi J, Park H. Correlation between genotype and phenotype in patients with bi-allelicSLC26A4mutations. Clin Genet 2013; 86:270-5. [DOI: 10.1111/cge.12273] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 09/03/2013] [Accepted: 09/03/2013] [Indexed: 11/27/2022]
Affiliation(s)
- H.J. Lee
- Department of Otorhinolaryngology
- BK21 Project for Medical Science
| | - J. Jung
- Department of Pharmacology; Yonsei University College of Medicine; Seoul Republic of Korea
- BK21 Project for Medical Science
| | - J.W. Shin
- Department of Otorhinolaryngology
- Soree Ear Clinics; Seoul Republic of Korea
| | | | - S.H. Kim
- Department of Otorhinolaryngology
| | - J.-H. Lee
- Department of Pharmacology; Yonsei University College of Medicine; Seoul Republic of Korea
| | - K.-A. Lee
- Department of Laboratory Medicine; Yonsei University College of Medicine; Seoul Republic of Korea
| | - S. Shin
- Department of Laboratory Medicine; Yonsei University College of Medicine; Seoul Republic of Korea
| | - U.-K. Kim
- Department of Biology, College of Natural Sciences; Kyungpook National University; Daegu Republic of Korea
| | - J. Bok
- Department of Anatomy; Yonsei University College of Medicine; Seoul Republic of Korea
| | - K.-Y. Lee
- Department of Otorhinolaryngology; Kyungpook National University; Daegu Republic of Korea
| | - J.Y. Choi
- Department of Otorhinolaryngology
- BK21 Project for Medical Science
| | - H.J. Park
- Soree Ear Clinics; Seoul Republic of Korea
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Alper SL, Sharma AK. The SLC26 gene family of anion transporters and channels. Mol Aspects Med 2013; 34:494-515. [PMID: 23506885 DOI: 10.1016/j.mam.2012.07.009] [Citation(s) in RCA: 256] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 06/21/2012] [Indexed: 02/08/2023]
Abstract
The phylogenetically ancient SLC26 gene family encodes multifunctional anion exchangers and anion channels transporting a broad range of substrates, including Cl(-), HCO3(-), sulfate, oxalate, I(-), and formate. SLC26 polypeptides are characterized by N-terminal cytoplasmic domains, 10-14 hydrophobic transmembrane spans, and C-terminal cytoplasmic STAS domains, and appear to be homo-oligomeric. SLC26-related SulP proteins of marine bacteria likely transport HCO3(-) as part of oceanic carbon fixation. SulP genes present in antibiotic operons may provide sulfate for antibiotic biosynthetic pathways. SLC26-related Sultr proteins transport sulfate in unicellular eukaryotes and in plants. Mutations in three human SLC26 genes are associated with congenital or early onset Mendelian diseases: chondrodysplasias for SLC26A2, chloride diarrhea for SLC26A3, and deafness with enlargement of the vestibular aqueduct for SLC26A4. Additional disease phenotypes evident only in mouse knockout models include oxalate urolithiasis for Slc26a6 and Slc26a1, non-syndromic deafness for Slc26a5, gastric hypochlorhydria for Slc26a7 and Slc26a9, distal renal tubular acidosis for Slc26a7, and male infertility for Slc26a8. STAS domains are required for cell surface expression of SLC26 proteins, and contribute to regulation of the cystic fibrosis transmembrane regulator in complex, cell- and tissue-specific ways. The protein interactomes of SLC26 polypeptides are under active investigation.
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Affiliation(s)
- Seth L Alper
- Renal Division and Division of Molecular and Vascular Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
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Yao G, Chen D, Wang H, Li S, Zhang J, Feng Z, Guo L, Yang Z, Yang S, Sun C, Zhang X, Ma D. Novel mutations of SLC26A4 in Chinese patients with nonsyndromic hearing loss. Acta Otolaryngol 2013; 133:833-41. [PMID: 23638949 DOI: 10.3109/00016489.2013.777160] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSIONS This study demonstrated high prevalence of GJB2, SLC26A4, and mtDNA A1555G mutations in Chinese patients with nonsyndromic hearing loss and discovered eight novel mutations in SLC26A4. Most of these novel mutations were predicted pathogenic variants. OBJECTIVES Nonsyndromic hearing loss is the most common neurosensory deafness where the majority of patients have highly diversified genetic defects. This study aimed to define the genetic profile of deafness in a Chinese population with potential to discover novel mutations. METHODS A total of 227 segregating deaf students and 200 individuals with normal hearing were enrolled. With the Sanger sequencing chemistry, direct sequencing was performed on entire coding regions of GJB2, GJB3, SLC26A4, and mtDNA m.C1494T and m.A1555G. RESULTS Direct sequencing analysis revealed that 53 (23.35%) of 227 patients carried at least 1 mutant allele in GJB2, 40 (17.62%) patients in SLC26A4, 5 (2.20%) patients in mtDNA A1555G, and 1 (0.44%) patient in mtDNA C1494T mutations. Four patients carried three unclassified mutations in GJB3 genes. Overall 38 mutant variants were detected in this cohort of patients, including 8 novel mutations in SLC26A4. The eight novel variants were six missense substitutions (p.V163L, p.G222S, p.A456D, p.N457I, p.C466Y, p.F667L), one nonsense mutation (p.W472X), and one frameshift (p.Asn612Ilefs×23).
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Affiliation(s)
- Gendong Yao
- Department of Laboratory Medicine, Central Hospital of Handan City, Hebei, China.
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Lu YC, Wu CC, Yang TH, Lin YH, Yu IS, Lin SW, Chang Q, Lin X, Wong JM, Hsu CJ. Differences in the pathogenicity of the p.H723R mutation of the common deafness-associated SLC26A4 gene in humans and mice. PLoS One 2013; 8:e64906. [PMID: 23755160 PMCID: PMC3670936 DOI: 10.1371/journal.pone.0064906] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Accepted: 04/19/2013] [Indexed: 11/23/2022] Open
Abstract
Mutations in the SLC26A4 gene are a common cause of human hereditary hearing impairment worldwide. Previous studies have demonstrated that different SLC26A4 mutations have different pathogenetic mechanisms. By using a genotype-driven approach, we established a knock-in mouse model (i.e., Slc26a4tm2Dontuh/tm2Dontuh mice) homozygous for the common p.H723R mutation in the East Asian population. To verify the pathogenicity of the p.H723R allele in mice, we further generated mice with compound heterozygous mutations (i.e., Slc26a4tm1Dontuh/tm2Dontuh) by intercrossing Slc26a4+/tm2Dontuh mice with Slc26a4tm1Dontuh/tm1Dontuh mice, which segregated the c.919-2A>G mutation with an abolished Slc26a4 function. Mice were then subjected to audiologic assessments, a battery of vestibular evaluations, inner ear morphological studies, and noise exposure experiments. The results were unexpected; both Slc26a4tm2Dontuh/tm2Dontuh and Slc26a4tm1Dontuh/tm2Dontuh mice showed normal audiovestibular phenotypes and inner ear morphology, and they did not show significantly higher shifts in hearing thresholds after noise exposure than the wild-type mice. The results indicated not only the p.H723R allele was non-pathogenic in mice, but also a single p.H723R allele was sufficient to maintain normal inner ear physiology in heterozygous compound mice. There might be discrepancies in the pathogenicity of specific SLC26A4 mutations in humans and mice; therefore, precautions should be taken when extrapolating the results of animal studies to humans.
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Affiliation(s)
- Ying-Chang Lu
- Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - Chen-Chi Wu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan
| | - Ting-Hua Yang
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - Yin-Hung Lin
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - I-Shing Yu
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center For Medical Excellence, National Taiwan University, Taipei, Taiwan
| | - Shu-Wha Lin
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center For Medical Excellence, National Taiwan University, Taipei, Taiwan
| | - Qing Chang
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Xi Lin
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Jau-Min Wong
- Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
| | - Chuan-Jen Hsu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Otolaryngology, College of Medicine, National Taiwan University, Taipei, Taiwan
- * E-mail:
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