1
|
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.
Collapse
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
| |
Collapse
|
3
|
Wen C, Yang X, Cheng X, Zhang W, Li Y, Wang J, Wang C, Ruan Y, Zhao L, Lu H, Li Y, Bai Y, Yu Y, Li Y, Xie J, Qi BE, En H, Liu H, Fu X, Huang L, Han D. Optimized concurrent hearing and genetic screening in Beijing, China: A cross-sectional study. Biosci Trends 2023; 17:148-159. [PMID: 37062750 DOI: 10.5582/bst.2023.01051] [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: 04/18/2023]
Abstract
Concurrent screening has been proven to provide a comprehensive approach for management of congenital deafness and prevention of ototoxicity. The SLC26A4 gene is associated with late-onset hearing loss and is of great clinical concern. For much earlier detection of newborns with deafness-causing mutations in the SLC26A4 gene, the Beijing Municipal Government launched a chip for optimized genetic screening of 15 variants of 4 genes causing deafness based on a chip to screen for 9 variants of 4 genes, and 6 variants of the SLC26A4 gene have now been added. To ascertain the advantage of a screening chip including 15 variants of 4 genes, the trends in concurrent hearing and genetic screening were analyzed in 2019 and 2020. Subjects were 76,460 newborns who underwent concurrent hearing and genetic screening at 24 maternal and child care centers in Beijing from January 2019 to December 2020. Hearing screening was conducted using transiently evoked otoacoustic emissions (TEOAEs), distortion product otoacoustic emissions (DPOAE), or the automated auditory brainstem response (AABR). Dried blood spots were collected for genetic testing and 15 variants of 4 genes, namely GJB2, SLC26A4, mtDNA 12S rRNA, and GJB3, were screened for using a DNA microarray platform. The initial referral rate for hearing screening decreased from 3.60% (1,502/41,690) in 2019 to 3.23% (1,124/34,770) in 2020, and the total referral rate for hearing screening dropped form 0.57% (236/41,690) in 2019 to 0.54% (187/34,770) in 2020, indicating the reduced false positive rate of newborn hearing screening and policies to prevent hearing loss conducted by the Beijing Municipal Government have had a significant effect. Positivity according to genetic screening was similar in 2019 (4.970%, 2,072/41,690) and 2020 (4.863%,1,691/34,770), and the most frequent mutant alleles were c.235 del C in the GJB2 gene, followed by c.919-2 A > G in the SLC26A4 gene, and c.299 del AT in the GJB2 gene. In this cohort study, 71.43% (5/7) of newborns with 2 variants of the SLC26A4 gene were screened for newly added mutations, and 28.57% (2/7) of newborns with 2 variants of the SLC26A4 gene passed hearing screening, suggesting that a screening chip including 15 variants of 4 genes was superior at early detection of hearing loss, and especially in early identification of newborns with deafness-causing mutations in the SLC26A4 gene. These findings have clinical significance.
Collapse
Affiliation(s)
- Cheng Wen
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Xiaozhe Yang
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Xiaohua Cheng
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Wei Zhang
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Yichen Li
- Maternal and Child Health, Beijing Obstetrics and Gynecology Hospital, Capital Medical University. Beijing Maternal and Child Health Care Hospital, Beijing, China
| | - Jing Wang
- Maternal and Child Health, Beijing Obstetrics and Gynecology Hospital, Capital Medical University. Beijing Maternal and Child Health Care Hospital, Beijing, China
| | - Chuan Wang
- Maternal and Child Health Hospital of Chao Yang District, Beijing, China
| | - Yu Ruan
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Liping Zhao
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Hongli Lu
- CapitalBio Corporation & National Engineering Research Center for Beijing Biochip Technology, Beijing, China
| | - Yingxin Li
- CapitalBio Corporation & National Engineering Research Center for Beijing Biochip Technology, Beijing, China
| | - Yue Bai
- CapitalBio Corporation & National Engineering Research Center for Beijing Biochip Technology, Beijing, China
| | - Yiding Yu
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Yue Li
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Jinge Xie
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Bei-Er Qi
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Hui En
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Hui Liu
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Xinxing Fu
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Lihui Huang
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Demin Han
- Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Beijing, China
- Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| |
Collapse
|
4
|
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.
Collapse
|
5
|
He X, Zhao S, Shi L, Lu Y, Yang Y, Zhang X. Compound heterozygous variants of the SLC26A4 gene in a Chinese family with enlarged vestibular aqueducts. BMC Med Genomics 2022; 15:152. [PMID: 35804348 PMCID: PMC9270741 DOI: 10.1186/s12920-022-01271-3] [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: 01/17/2022] [Accepted: 05/10/2022] [Indexed: 11/21/2022] Open
Abstract
Background To investigate the genetic causes of hearing loss in patients with enlarged vestibular aqueduct (EVA), the SLC26A4-related genotypes and phenotypes were analyzed. SLC26A4 gene is closely associated with EVA and its homozygous mutations or compound heterozygous mutations may cause deafness and strongly affect quality of life. Methods The patients who came to our hospital for hearing test and accompanied by bilateral hearing abnormalities were collected for fifteen deafness-related gene mutations detection. Those who are positive will be verified by Sanger sequencing, combined with family history, hearing test, and computerized tomography (CT) of the temporal bone, aiming to diagnose the enlarged vestibular aqueducts. Whole-exome sequencing were performed when necessary. Results Our patient failed hearing screening on both sides twice, and EVA (> 1.5 mm) was diagnosed by CT. This study has identified a novel missense mutation in the SLC26A4 gene, c.2069T>A, which in compound heterozygosity with c.1174A>T is likely to be the cause of hearing loss. The novel heterozygous c.2069T>A mutation of SLC26A4 gene has been submitted to Clinvar with Variation ID 1,048,780. Conclusion Our findings expand the gene mutation spectrum of SLC26A4 and provide additional knowledge for diagnosis and genetic counseling associated with EVA-induced hearing loss. Supplementary Information The online version contains supplementary material available at 10.1186/s12920-022-01271-3.
Collapse
Affiliation(s)
- Xiaohui He
- Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, China
| | - Shaozhi Zhao
- Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, China
| | - Lin Shi
- Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, China
| | - Yitong Lu
- Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, China
| | - Yintong Yang
- Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, China
| | - Xinwen Zhang
- Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, China.
| |
Collapse
|
7
|
Kınoğlu K, Orhan KS, Kara H, Öztürk O, Polat B, Aydoğan H, Çelik M, Ceviz AB, Güldiken Y. Investigation of DFNB4 SLC26A4 mutation in patients with enlarged vestibular aquaduct. Int J Pediatr Otorhinolaryngol 2020; 138:110379. [PMID: 33152970 DOI: 10.1016/j.ijporl.2020.110379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/02/2020] [Accepted: 09/09/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Mutations of the SLC26A4 gene causing enlarged vestibular aqueduct (EVA) syndrome have not yet been fully elucidated. The study aimed to investigate SLC26A4 mutations in patients with EVA syndrome in the Turkish population. Identifying these mutations may play an essential role in determining the prognosis, follow-up, and management options of these patients. METHODS Whole exome sequencing and/or Sanger sequencing of SLC26A4 in 22 patients with sensorineural hearing loss associated with isolated EVA without inner ear anomalies, and 22 controls were performed. RESULTS Twenty-two patients and 22 control subjects were included in the study. The onset of hearing loss was pre-lingual in 15 patients, and post-lingual in 7. The mean (standard deviation) vestibular aqueduct width of the patients was 3.23 mm (1.28). Twenty SLC26A4 variants, 15 of them unique, were identified in 22 patients. Among them, seven variants were heterozygous, and 13 were homozygous. The variants p.E37X (c.109G > T), p.Y27H (c.79T > C), p.C706Y (c.2117G > A) have not been previously reported. CONCLUSION The detection of rare and previously unreported mutations in our study showed that studies with a larger number of patients with EVA might reveal more role of the SLC26A4 gene. Besides, to understand the etiopathogenesis of the disease, other related genes also should be investigated.
Collapse
Affiliation(s)
- Kubilay Kınoğlu
- Istanbul University, Aziz Sancar Institute of Experimental Medicine, Turkey
| | - Kadir Serkan Orhan
- Istanbul University, Istanbul Faculty of Medicine, Department of Otorhinolaryngology
| | - Hakan Kara
- Istanbul University, Istanbul Faculty of Medicine, Department of Otorhinolaryngology.
| | - Oğuz Öztürk
- Istanbul University, Aziz Sancar Institute of Experimental Medicine, Turkey
| | - Beldan Polat
- Istanbul University, Istanbul Faculty of Medicine, Department of Otorhinolaryngology
| | - Hülya Aydoğan
- Istanbul University, Aziz Sancar Institute of Experimental Medicine, Turkey
| | - Mehmet Çelik
- Istanbul University, Istanbul Faculty of Medicine, Department of Otorhinolaryngology
| | - Ayşe Begüm Ceviz
- Istanbul University, Aziz Sancar Institute of Experimental Medicine, Turkey
| | - Yahya Güldiken
- Istanbul University, Istanbul Faculty of Medicine, Department of Otorhinolaryngology
| |
Collapse
|