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Sreedevi N, Swapna N, Maruthy S, Jayakumar T, Sylvester C. Molecular Evaluation of Joubert Syndrome and Hearing Impairment in a Patient with Ataxic Cerebral Palsy. Glob Med Genet 2023; 10:190-193. [PMID: 37501760 PMCID: PMC10370468 DOI: 10.1055/s-0043-1771184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 06/20/2023] [Indexed: 07/29/2023] Open
Abstract
Joubert syndrome (JBTS) is a rare autosomal recessive or X-linked congenital brain malformation with strong genetic heterogeneity. Other neurological features of JBTS include hypotonia, ataxia, developmental delay, and cognitive impairment. Hearing loss with JBTS has been reported in the literature. We present the case of a 3.5-year-old boy born to a healthy consanguineous South Indian couple who was presented with ataxic cerebral palsy (CP) and hearing impairment; medical reports confirmed typical brain malformations of JBTS. Hearing impairment was screened by audiological assessment, which confirmed the presence of severe-profound hearing loss with outer hair cell dysfunction. Whole-exome sequencing (WES) was performed to know the molecular aspects of the condition and to detect any novel mutations. The homozygous mutation AHI1 c.2023G > A associated with JBTS type 3 and GJB2 c.71G > A mutation associated with hearing impairment were identified. Sanger sequencing was performed to validate the result and it identified heterozygous AHI1 c.2023G > A and GJB2 c.71G > A in the patient's parents. This study confirms the diagnosis of JBTS by WES helps identify the genetic causes of hereditary disorders that accelerate genetic evaluation and counseling for at-risk families.
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Affiliation(s)
- N. Sreedevi
- Department of Speech-Language Sciences, All India Institute of Speech and Hearing, Mysore, India
| | - N. Swapna
- Department of Speech-Language Pathology, All India Institute of Speech and Hearing, Mysore, India
| | - Santosh Maruthy
- Department of Speech-Language Sciences, All India Institute of Speech and Hearing, Mysore, India
| | - T. Jayakumar
- Department of Speech-Language Sciences, All India Institute of Speech and Hearing, Mysore, India
| | - Charles Sylvester
- Unit for Human Genetics, All India Institute of Speech and Hearing, Mysore, India
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Chen T, Rohacek AM, Caporizzo M, Nankali A, Smits JJ, Oostrik J, Lanting CP, Kücük E, Gilissen C, van de Kamp JM, Pennings RJE, Rakowiecki SM, Kaestner KH, Ohlemiller KK, Oghalai JS, Kremer H, Prosser BL, Epstein DJ. Cochlear supporting cells require GAS2 for cytoskeletal architecture and hearing. Dev Cell 2021; 56:1526-1540.e7. [PMID: 33964205 PMCID: PMC8137675 DOI: 10.1016/j.devcel.2021.04.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/01/2021] [Accepted: 04/16/2021] [Indexed: 11/16/2022]
Abstract
In mammals, sound is detected by mechanosensory hair cells that are activated in response to vibrations at frequency-dependent positions along the cochlear duct. We demonstrate that inner ear supporting cells provide a structural framework for transmitting sound energy through the cochlear partition. Humans and mice with mutations in GAS2, encoding a cytoskeletal regulatory protein, exhibit hearing loss due to disorganization and destabilization of microtubule bundles in pillar and Deiters' cells, two types of inner ear supporting cells with unique cytoskeletal specializations. Failure to maintain microtubule bundle integrity reduced supporting cell stiffness, which in turn altered cochlear micromechanics in Gas2 mutants. Vibratory responses to sound were measured in cochleae from live mice, revealing defects in the propagation and amplification of the traveling wave in Gas2 mutants. We propose that the microtubule bundling activity of GAS2 imparts supporting cells with mechanical properties for transmitting sound energy through the cochlea.
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Affiliation(s)
- Tingfang Chen
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Alex M Rohacek
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Matthew Caporizzo
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Amir Nankali
- The Caruso Department of Otolaryngology-Head and Neck Surgery, University of Southern California, Los Angeles, CA, USA
| | - Jeroen J Smits
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Jaap Oostrik
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Cornelis P Lanting
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Erdi Kücük
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Jiddeke M van de Kamp
- Department of Clinical Genetics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Ronald J E Pennings
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Staci M Rakowiecki
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Klaus H Kaestner
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kevin K Ohlemiller
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA
| | - John S Oghalai
- The Caruso Department of Otolaryngology-Head and Neck Surgery, University of Southern California, Los Angeles, CA, USA
| | - Hannie Kremer
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Benjamin L Prosser
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Douglas J Epstein
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Beach R, Abitbol JM, Allman BL, Esseltine JL, Shao Q, Laird DW. GJB2 Mutations Linked to Hearing Loss Exhibit Differential Trafficking and Functional Defects as Revealed in Cochlear-Relevant Cells. Front Cell Dev Biol 2020; 8:215. [PMID: 32300592 PMCID: PMC7142214 DOI: 10.3389/fcell.2020.00215] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/12/2020] [Indexed: 11/13/2022] Open
Abstract
GJB2 gene (that encodes Cx26) mutations are causal of hearing loss highlighting the importance of Cx26-based channel signaling amongst the supporting cells in the organ of Corti. While the majority of these GJB2 mutations are inherited in an autosomal recessive manner, others are inherited in an autosomal dominant manner and lead to syndromic hearing loss as well as skin diseases. To assess if common or divergent mechanisms are at the root of GJB2-linked hearing loss, we expressed several mutants in cochlear-relevant HEI-OC1 cells derived from the developing organ of Corti. Since supporting cells of the mature mammalian organ of Corti have negligible Cx43, but HEI-OC1 cells are rich in Cx43, we first used CRISPR-Cas9 to ablate endogenous Cx43, thus establishing a connexin-deficient platform for controlled reintroduction of hearing-relevant connexins and Cx26 mutants. We found three distinct outcomes and cellular phenotypes when hearing loss-linked Cx26 mutants were expressed in cochlear-relevant cells. The dominant syndromic Cx26 mutant N54K had trafficking defects and did not fully prevent wild-type Cx26 gap junction plaque formation but surprisingly formed gap junctions when co-expressed with Cx30. In contrast, the dominant syndromic S183F mutant formed gap junctions incapable of transferring dye and, as expected, co-localized in the same gap junctions as wild-type Cx26 and Cx30, but also gained the capacity to intermix with Cx43 within gap junctions. Both recessive non-syndromic Cx26 mutants (R32H and R184P) were retained in intracellular vesicles including early endosomes and did not co-localize with Cx30. As might be predicted, none of the Cx26 mutants prevented Cx43 gap junction plaque formation in Cx43-rich HEI-OC1 cells while Cx43-ablation had little effect on the expression of reference genes linked to auditory cell differentiation. We conclude from our studies in cochlear-relevant cells that the selected Cx26 mutants likely evoke hearing loss via three unique connexin defects that are independent of Cx43 status.
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Affiliation(s)
- Rianne Beach
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Julia M. Abitbol
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Brian L. Allman
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Jessica L. Esseltine
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Qing Shao
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Dale W. Laird
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
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Ghelfi E, Grondin Y, Millet EJ, Bartos A, Bortoni M, Oliveira Gomes Dos Santos C, Trevino-Villarreal HJ, Sepulveda R, Rogers R. In vitro gentamicin exposure alters caveolae protein profile in cochlear spiral ligament pericytes. Proteome Sci 2018; 16:7. [PMID: 29760588 PMCID: PMC5938607 DOI: 10.1186/s12953-018-0132-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 02/04/2018] [Indexed: 12/20/2022] Open
Abstract
Background The aminoglycoside antibiotic gentamicin is an ototoxic drug and has been used experimentally to investigate cochlear damage induced by noise.We have investigated the changes in the protein profile associated with caveolae in gentamicin treated and untreated spiral ligament (SL) pericytes, specialized cells in the blood labyrinth barrier of the inner ear microvasculature. Pericytes from various microvascular beds express caveolae, protein and cholesterol rich microdomains, which can undergo endocytosis and transcytosis to transport small molecules in and out the cells. A different protein profile in transport-specialized caveolae may induce pathological changes affecting the integrity of the blood labyrinth barrier and ultimately contributing to hearing loss. Method Caveolae isolation from treated and untreated cells is achieved through ultracentrifugation of the lysates in discontinuous gradients. Mass spectrometry (LC-MS/MS) analysis identifies the proteins in the two groups. Proteins segregating with caveolae isolated from untreated SL pericytes are then compared to caveolae isolated from SL pericytes treated with the gentamicin for 24 h. Data are analyzed using bioinformatic tools. Results The caveolae proteome in gentamicin treated cells shows that 40% of total proteins are uniquely associated with caveolae during the treatment, and 15% of the proteins normally associated with caveolae in untreated cell are suppressed. Bioinformatic analysis of the data shows a decreased expression of proteins involved in genetic information processing, and an increase in proteins involved in metabolism, vesicular transport and signal transduction in gentamicin treated cells. Several Rab GTPases proteins, ubiquitous transporters, uniquely segregate with caveolae and are significantly enriched in gentamicin treated cells. Conclusion We report that gentamicin exposure modifies protein profile of caveolae from SL pericytes. We identified a pool of proteins which are uniquely segregating with caveolae during the treatment, mainly participating in metabolic and biosynthetic pathways, in transport pathways and in genetic information processing. Finally, we show for the first time proteins associated with caveolae SL pericytes linked to nonsyndromic hearing loss.
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Affiliation(s)
- Elisa Ghelfi
- 1Harvard T.H. Chan School of Public Health, Department of Environmental Health, MIPS Program, Boston, MA USA
| | - Yohann Grondin
- 1Harvard T.H. Chan School of Public Health, Department of Environmental Health, MIPS Program, Boston, MA USA
| | - Emil J Millet
- 1Harvard T.H. Chan School of Public Health, Department of Environmental Health, MIPS Program, Boston, MA USA
| | - Adam Bartos
- 1Harvard T.H. Chan School of Public Health, Department of Environmental Health, MIPS Program, Boston, MA USA
| | - Magda Bortoni
- 1Harvard T.H. Chan School of Public Health, Department of Environmental Health, MIPS Program, Boston, MA USA
| | - Clara Oliveira Gomes Dos Santos
- 1Harvard T.H. Chan School of Public Health, Department of Environmental Health, MIPS Program, Boston, MA USA.,2Universidade de Sao Paulo, Faculdade de Medicina, Sao Paulo, Brazil
| | | | - Rosalinda Sepulveda
- 1Harvard T.H. Chan School of Public Health, Department of Environmental Health, MIPS Program, Boston, MA USA.,4Universidad Autónoma de Nuevo León, Facultad de Medicina, Monterrey, Mexico
| | - Rick Rogers
- 1Harvard T.H. Chan School of Public Health, Department of Environmental Health, MIPS Program, Boston, MA USA
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Mittal R, Debs LH, Nguyen D, Patel AP, Grati M, Mittal J, Yan D, Eshraghi AA, Liu XZ. Signaling in the Auditory System: Implications in Hair Cell Regeneration and Hearing Function. J Cell Physiol 2017; 232:2710-2721. [DOI: 10.1002/jcp.25695] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 11/18/2016] [Indexed: 02/06/2023]
Affiliation(s)
- Rahul Mittal
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Luca H. Debs
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Desiree Nguyen
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Amit P. Patel
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - M'hamed Grati
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Jeenu Mittal
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Denise Yan
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Adrien A. Eshraghi
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Xue Zhong Liu
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
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