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Wang D, Wang H, Fan L, Ludwig T, Wegner A, Stahl F, Harre J, Warnecke A, Zeilinger C. A Chemical Chaperone Restores Connexin 26 Mutant Activity. ACS Pharmacol Transl Sci 2023; 6:997-1005. [PMID: 37470015 PMCID: PMC10353060 DOI: 10.1021/acsptsci.3c00056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Indexed: 07/21/2023]
Abstract
Mutations in connexin 26 (Cx26) cause hearing disorders of a varying degree. Herein, to identify compounds capable of restoring the function of mutated Cx26, a novel miniaturized microarray-based screening system was developed to perform an optical assay of Cx26 functionality. These molecules were identified through a viability assay using HeLa cells expressing wild-type (WT) Cx26, which exhibited sensitivity toward the HSP90 inhibitor radicicol in the submicromolar concentration range. Open Cx26 hemichannels are assumed to mediate the passage of molecules up to 1000 Da in size. Thus, by releasing radicicol, WT Cx26 active hemichannels in HeLa cells contribute to a higher survival rate and lower cell viability when Cx26 is mutated. HeLa cells expressing Cx26 mutations exhibited reduced viability in the presence of radicicol, such as the mutants F161S or R184P. Next, molecules exhibiting chemical chaperoning activity, suspected of restoring channel function, were assessed regarding whether they induced superior sensitivity toward radicicol and increased HeLa cell viability. Through a viability assay and microarray-based flux assay that uses Lucifer yellow in HeLa cells, compounds 3 and 8 were identified to restore mutant functionality. Furthermore, thermophoresis experiments revealed that only 3 (VRT-534) exhibited dose-responsive binding to recombinant WT Cx26 and mutant Cx26K188N with half maximal effective concentration values of 19 and ∼5 μM, respectively. The findings of this study reveal that repurposing compounds already being used to treat other diseases, such as cystic fibrosis, in combination with functional bioassays and binding tests can help identify novel potential candidates that can be used to treat hearing disorders.
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Affiliation(s)
- Dahua Wang
- Gottfried-Wilhelm-Leibniz
University of Hannover, BMWZ (Zentrum für
Biomolekulare Wirkstoffe), Schneiderberg 38, 30167 Hannover, Germany
- Clinic
for Otorhinolaryngology Surgery, Hannover
Medical School (MHH), 30625 Hannover, Germany
| | - Hongling Wang
- Gottfried-Wilhelm-Leibniz
University of Hannover, BMWZ (Zentrum für
Biomolekulare Wirkstoffe), Schneiderberg 38, 30167 Hannover, Germany
- Clinic
for Otorhinolaryngology Surgery, Hannover
Medical School (MHH), 30625 Hannover, Germany
| | - Lu Fan
- Gottfried-Wilhelm-Leibniz
University of Hannover, BMWZ (Zentrum für
Biomolekulare Wirkstoffe), Schneiderberg 38, 30167 Hannover, Germany
- Clinic
for Otorhinolaryngology Surgery, Hannover
Medical School (MHH), 30625 Hannover, Germany
| | - Tobias Ludwig
- Technische
Universität Braunschweig, Braunschweig Integrated Centre of
Systems Biology (BRICS), Department of Bioinformatics
and Biochemistry, Rebenring
56, 38106 Braunschweig, Germany
| | - Andre Wegner
- Technische
Universität Braunschweig, Braunschweig Integrated Centre of
Systems Biology (BRICS), Department of Bioinformatics
and Biochemistry, Rebenring
56, 38106 Braunschweig, Germany
| | - Frank Stahl
- Gottfried-Wilhelm-Leibniz
University of Hannover, Institut für
Technische Chemie/BMWZ (Zentrum für Biomolekulare Wirkstoffe), Callinstr. 5, 30167 Hannover, Germany
| | - Jennifer Harre
- Clinic
for Otorhinolaryngology Surgery, Hannover
Medical School (MHH), 30625 Hannover, Germany
| | - Athanasia Warnecke
- Clinic
for Otorhinolaryngology Surgery, Hannover
Medical School (MHH), 30625 Hannover, Germany
| | - Carsten Zeilinger
- Gottfried-Wilhelm-Leibniz
University of Hannover, BMWZ (Zentrum für
Biomolekulare Wirkstoffe), Schneiderberg 38, 30167 Hannover, Germany
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Le Nabec A, Blotas C, Briset A, Collobert M, Férec C, Moisan S. 3D Chromatin Organization Involving MEIS1 Factor in the cis-Regulatory Landscape of GJB2. Int J Mol Sci 2022; 23:ijms23136964. [PMID: 35805969 PMCID: PMC9266880 DOI: 10.3390/ijms23136964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/17/2022] [Accepted: 06/21/2022] [Indexed: 02/04/2023] Open
Abstract
The human genome is covered by 8% of candidate cis-regulatory elements. The identification of distal acting regulatory elements and an understanding of their action are crucial to determining their key role in gene expression. Disruptions of such regulatory elements and/or chromatin conformation are likely to play a critical role in human genetic diseases. Non-syndromic hearing loss (i.e., DFNB1) is mostly due to GJB2 (Gap Junction Beta 2) variations and DFNB1 large deletions. Although several GJB2 cis-regulatory elements (CREs) have been described, GJB2 gene regulation remains not well understood. We investigated the endogenous effect of these CREs with CRISPR (clustered regularly interspaced short palindromic repeats) disruptions and observed GJB2 expression. To decipher the GJB2 regulatory landscape, we used the 4C-seq technique and defined new chromatin contacts inside the DFNB1 locus, which permit DNA loops and long-range regulation. Moreover, through ChIP-PCR, we determined the involvement of the MEIS1 transcription factor in GJB2 expression. Taken together, the results of our study enable us to describe the 3D DFNB1 regulatory landscape.
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Affiliation(s)
- Anaïs Le Nabec
- University Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.B.); (A.B.); (M.C.); (C.F.)
- Correspondence: or twitter@anaisnabec (A.L.N.); (S.M.); Tel.: +33-2-98-01-65-84 (A.L.N.); +33-2-98-01-65-67 (S.M.)
| | - Clara Blotas
- University Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.B.); (A.B.); (M.C.); (C.F.)
| | - Alinéor Briset
- University Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.B.); (A.B.); (M.C.); (C.F.)
| | - Mégane Collobert
- University Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.B.); (A.B.); (M.C.); (C.F.)
| | - Claude Férec
- University Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.B.); (A.B.); (M.C.); (C.F.)
| | - Stéphanie Moisan
- University Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.B.); (A.B.); (M.C.); (C.F.)
- Laboratoire de Génétique Moléculaire et d’Histocompatibilité, CHRU Brest, UMR 1078, F-29200 Brest, France
- Correspondence: or twitter@anaisnabec (A.L.N.); (S.M.); Tel.: +33-2-98-01-65-84 (A.L.N.); +33-2-98-01-65-67 (S.M.)
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Evaluation of copy number variants for genetic hearing loss: a review of current approaches and recent findings. Hum Genet 2021; 141:387-400. [PMID: 34811589 DOI: 10.1007/s00439-021-02365-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/02/2021] [Indexed: 01/22/2023]
Abstract
Structural variation includes a change in copy number, orientation, or location of a part of the genome. Copy number variants (CNVs) are a common cause of genetic hearing loss, comprising nearly 20% of diagnosed cases. While large deletions involving the gene STRC are the most common pathogenic CNVs, a significant proportion of known hearing loss genes also contain pathogenic CNVs. In this review, we provide an overview of currently used methods for detection of CNVs in genes known to cause hearing loss including molecular techniques such as multiplex ligation probe amplification (MLPA) and digital droplet polymerase chain reaction (ddPCR), array-CGH and single-nucleotide polymorphism (SNP) arrays, as well as techniques for detection of CNVs using next-generation sequencing data analysis including targeted gene panel, exome, and genome sequencing data. In addition, in this review, we compile published data on pathogenic hearing loss CNVs to provide an up-to-date overview. We show that CNVs have been identified in 29 different non-syndromic hearing loss genes. An understanding of the contribution of CNVs to genetic hearing loss is critical to the current diagnosis of hearing loss and is crucial for future gene therapies. Thus, evaluation for CNVs is required in any modern pipeline for genetic diagnosis of hearing loss.
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Le Nabec A, Collobert M, Le Maréchal C, Marianowski R, Férec C, Moisan S. Whole-Genome Sequencing Improves the Diagnosis of DFNB1 Monoallelic Patients. Genes (Basel) 2021; 12:1267. [PMID: 34440441 PMCID: PMC8391926 DOI: 10.3390/genes12081267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 08/13/2021] [Accepted: 08/17/2021] [Indexed: 11/16/2022] Open
Abstract
Hearing loss is the most common sensory defect, due in most cases to a genetic origin. Variants in the GJB2 gene are responsible for up to 30% of non-syndromic hearing loss. Today, several deafness genotypes remain incomplete, confronting us with a diagnostic deadlock. In this study, whole-genome sequencing (WGS) was performed on 10 DFNB1 patients with incomplete genotypes. New variations on GJB2 were identified for four patients. Functional assays were realized to explore the function of one of them in the GJB2 promoter and confirm its impact on GJB2 expression. Thus, in this study WGS resolved patient genotypes, thus unlocking diagnosis. WGS afforded progress and bridged some gaps in our research.
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Affiliation(s)
- Anaïs Le Nabec
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (M.C.); (C.L.M.); (C.F.)
| | - Mégane Collobert
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (M.C.); (C.L.M.); (C.F.)
| | - Cédric Le Maréchal
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (M.C.); (C.L.M.); (C.F.)
- Laboratoire de Génétique Moléculaire et d’Histocompatibilité, CHRU Brest, UMR 1078, F-29200 Brest, France
| | - Rémi Marianowski
- Service ORL et Chirurgie Cervicofaciale du CHRU Brest, F-29200 Brest, France;
| | - Claude Férec
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (M.C.); (C.L.M.); (C.F.)
- Laboratoire de Génétique Moléculaire et d’Histocompatibilité, CHRU Brest, UMR 1078, F-29200 Brest, France
| | - Stéphanie Moisan
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (M.C.); (C.L.M.); (C.F.)
- Laboratoire de Génétique Moléculaire et d’Histocompatibilité, CHRU Brest, UMR 1078, F-29200 Brest, France
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M. Adadey S, Tingang Wonkam E, Twumasi Aboagye E, Quansah D, Asante-Poku A, Quaye O, K. Amedofu G, A. Awandare G, Wonkam A. Enhancing Genetic Medicine: Rapid and Cost-Effective Molecular Diagnosis for a GJB2 Founder Mutation for Hearing Impairment in Ghana. Genes (Basel) 2020; 11:genes11020132. [PMID: 32012697 PMCID: PMC7074138 DOI: 10.3390/genes11020132] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 12/17/2022] Open
Abstract
In Ghana, gap-junction protein β 2 (GJB2) variants account for about 25.9% of familial hearing impairment (HI) cases. The GJB2-p.Arg143Trp (NM_004004.6:c.427C>T/OMIM: 121011.0009/rs80338948) variant remains the most frequent variant associated with congenital HI in Ghana, but has not yet been investigated in clinical practice. We therefore sought to design a rapid and cost-effective test to detect this variant. We sampled 20 hearing-impaired and 10 normal hearing family members from 8 families segregating autosomal recessive non syndromic HI. In addition, a total of 111 unrelated isolated individuals with HI were selected, as well as 50 normal hearing control participants. A restriction fragment length polymorphism (RFLP) test was designed, using the restriction enzyme NciI optimized and validated with Sanger sequencing, for rapid genotyping of the common GJB2-p.Arg143Trp variant. All hearing-impaired participants from 7/8 families were homozygous positive for the GJB2-p.Arg143Trp mutation using the NciI-RFLP test, which was confirmed with Sanger sequencing. The investigation of 111 individuals with isolated non-syndromic HI that were previously Sanger sequenced found that the sensitivity of the GJB2-p.Arg143Trp NciI-RFLP testing was 100%. All the 50 control subjects with normal hearing were found to be negative for the variant. Although the test is extremely valuable, it is not 100% specific because it cannot differentiate between other mutations at the recognition site of the restriction enzyme. The GJB2-p.Arg143Trp NciI-RFLP-based diagnostic test had a high sensitivity for genotyping the most common GJB2 pathogenic and founder variant (p.Arg143Trp) within the Ghanaian populations. We recommend the adoption and implementation of this test for hearing impairment genetic clinical investigations to complement the newborn hearing screening program in Ghana. The present study is a practical case scenario of enhancing genetic medicine in Africa.
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Affiliation(s)
- Samuel M. Adadey
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra P. O. Box LG 54, Ghana; (S.M.A.); (E.T.A.); (D.Q.); (A.A.-P.); (O.Q.); (G.A.A.)
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa;
| | - Edmond Tingang Wonkam
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa;
| | - Elvis Twumasi Aboagye
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra P. O. Box LG 54, Ghana; (S.M.A.); (E.T.A.); (D.Q.); (A.A.-P.); (O.Q.); (G.A.A.)
| | - Darius Quansah
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra P. O. Box LG 54, Ghana; (S.M.A.); (E.T.A.); (D.Q.); (A.A.-P.); (O.Q.); (G.A.A.)
| | - Adwoa Asante-Poku
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra P. O. Box LG 54, Ghana; (S.M.A.); (E.T.A.); (D.Q.); (A.A.-P.); (O.Q.); (G.A.A.)
- Bacteriology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra P.O. Box LG 581, Ghana
| | - Osbourne Quaye
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra P. O. Box LG 54, Ghana; (S.M.A.); (E.T.A.); (D.Q.); (A.A.-P.); (O.Q.); (G.A.A.)
| | - Geoffrey K. Amedofu
- Department of Eye Ear Nose & Throat, School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi AK-039-5028, Ghana;
| | - Gordon A. Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra P. O. Box LG 54, Ghana; (S.M.A.); (E.T.A.); (D.Q.); (A.A.-P.); (O.Q.); (G.A.A.)
| | - Ambroise Wonkam
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa;
- Correspondence: ; Tel.: +27-21-4066-307
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