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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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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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Lopez-Escamez JA, Cheng AG, Grill E, Liu TC. Editorial: Epidemiology and Genetics of Vestibular Disorders. Front Neurol 2021; 12:743379. [PMID: 34630314 PMCID: PMC8498025 DOI: 10.3389/fneur.2021.743379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 08/16/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Jose A Lopez-Escamez
- Otology and Neurotology Group CTS495, Department of Genomic Medicine, GENYO - Centre for Genomics and Oncological Research - Pfizer/University of Granada/Junta de Andalucía, Parque Tecnologico de la Salud (PTS), Granada, Spain.,Department of Otolaryngology, Instituto de Investigación Biosanitaria, ibs.GRANADA, Hospital Universitario Virgen de las Nieves, Granada, Spain.,Division of Otolaryngology, Department of Surgery, Universidad de Granada, Granada, Spain.,Sensorineural Pathology Programme, Centro de Investigacion Biomédica en Red en Enfermedades Raras (CIBERER), Madrid, Spain
| | - Alan G Cheng
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
| | - Eva Grill
- Institute for Medical Information Processing, Biometrics and Epidemiology, Ludwig-Maximilians-Universität München (LMU) Munich, Munich, Germany.,German Center for Vertigo and Balance Disorders, University Hospital Munich, Ludwig-Maximilians-Universität München (LMU) Munich, Munich, Germany.,Munich Centre of Health Sciences, Ludwig-Maximilians-Universität München (LMU) Munich, Munich, Germany
| | - Tien-Chen Liu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
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Honda K, Griffith AJ. Genetic architecture and phenotypic landscape of SLC26A4-related hearing loss. Hum Genet 2021; 141:455-464. [PMID: 34345941 DOI: 10.1007/s00439-021-02311-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 06/29/2021] [Indexed: 12/15/2022]
Abstract
Mutations of coding regions and splice sites of SLC26A4 cause Pendred syndrome and nonsyndromic recessive hearing loss DFNB4. SLC26A4 encodes pendrin, a transmembrane exchanger of anions and bases. The mutant SLC26A4 phenotype is characterized by inner ear malformations, including an enlarged vestibular aqueduct (EVA), incomplete cochlear partition type II and modiolar hypoplasia, progressive and fluctuating hearing loss, and vestibular dysfunction. A thyroid iodine organification defect can lead to multinodular goiter and distinguishes Pendred syndrome from DFNB4. Pendred syndrome and DFNB4 are each inherited as an autosomal recessive trait caused by biallelic mutations of SLC26A4 (M2). However, there are some EVA patients with only one detectable mutant allele (M1) of SLC26A4. In most European-Caucasian M1 patients, there is a haplotype that consists of 12 variants upstream of SLC26A4, called CEVA (Caucasian EVA), which acts as a pathogenic recessive allele in trans to mutations affecting the coding regions or splice sites of SLC26A4. This combination of an M1 genotype with the CEVA haplotype is associated with a less severe phenotype than the M2 genotype. The phenotype in EVA patients with no mutant alleles of SLC26A4 (M0) has a very low recurrence probability and is likely to be caused by other factors.
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Affiliation(s)
- Keiji Honda
- Department of Otorhinolaryngology, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Andrew J Griffith
- Department of Otolaryngology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA.
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