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Gong X, Liu Y, Zhang Q, Liang K, Wei J, Du H. LHFPL2 Serves as a Potential Biomarker for M2 Polarization of Macrophages in Renal Cell Carcinoma. Int J Mol Sci 2024; 25:6707. [PMID: 38928412 PMCID: PMC11204190 DOI: 10.3390/ijms25126707] [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: 05/19/2024] [Revised: 06/04/2024] [Accepted: 06/10/2024] [Indexed: 06/28/2024] Open
Abstract
Renal cell carcinoma (RCC) is one of the most common malignant tumors of the kidney, presenting significant challenges for clinical diagnosis and treatment. Macrophages play crucial roles in RCC, promoting tumor progression and warranting further investigation. Previous studies have identified LHFPL2 as a transmembrane protein associated with reproduction, but its relationship with tumors or macrophages has not been discussed. This study utilized transcriptomic sequencing data from 609 KIRC patients in the TCGA database and single-cell sequencing data from 34,326 renal carcinoma cells for subsequent analysis. We comprehensively evaluated the expression of LHFPL2 and its relationship with clinical features, tumor prognosis, immune infiltration, and mutations. Additionally, we further assessed the correlation between LHFPL2 and macrophage M2 polarization using single-cell data and explored its potential as a cancer therapeutic target through molecular docking. The results demonstrated that LHFPL2 is upregulated in RCC and associated with poor survival rates. In clinical staging, the proportion of malignant and high-metastasis patients was higher in the high-LHFPL2 group than in the low-LHFPL2 group. Furthermore, we found that LHFPL2 influences RCC immune infiltration, with its expression positively correlated with various immune checkpoint and M2-related gene expressions, positively associated with M2 macrophage infiltration, and negatively correlated with activated NK cells. Moreover, LHFPL2 showed specific expression in macrophages, with the high-expression subgroup exhibiting higher M2 polarization, hypoxia, immune evasion, and angiogenesis scores, promoting tumor progression. Finally, we predicted several potential drugs targeting LHFPL2, such as conivaptan and nilotinib. Our analysis elaborately delineates the immune characteristics of LHFPL2 in the tumor microenvironment and its positive correlation with macrophage M2 polarization, providing new insights into tumor immunotherapy. We also propose potential FDA-approved drugs targeting this gene, which should be tested for their binding effects with LHFPL2 in future studies.
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Affiliation(s)
| | | | | | | | | | - Hongli Du
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China; (X.G.); (Y.L.); (Q.Z.); (K.L.); (J.W.)
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2
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Shadab M, Abbasi AA, Ejaz A, Ben-Mahmoud A, Gupta V, Kim HG, Vona B. Autosomal recessive non-syndromic hearing loss genes in Pakistan during the previous three decades. J Cell Mol Med 2024; 28:e18119. [PMID: 38534090 DOI: 10.1111/jcmm.18119] [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: 06/25/2023] [Revised: 11/29/2023] [Accepted: 01/02/2024] [Indexed: 03/28/2024] Open
Abstract
Hearing loss is a clinically and genetically heterogeneous disorder, with over 148 genes and 170 loci associated with its pathogenesis. The spectrum and frequency of causal variants vary across different genetic ancestries and are more prevalent in populations that practice consanguineous marriages. Pakistan has a rich history of autosomal recessive gene discovery related to non-syndromic hearing loss. Since the first linkage analysis with a Pakistani family that led to the mapping of the DFNB1 locus on chromosome 13, 51 genes associated with this disorder have been identified in this population. Among these, 13 of the most prevalent genes, namely CDH23, CIB2, CLDN14, GJB2, HGF, MARVELD2, MYO7A, MYO15A, MSRB3, OTOF, SLC26A4, TMC1 and TMPRSS3, account for more than half of all cases of profound hearing loss, while the prevalence of other genes is less than 2% individually. In this review, we discuss the most common autosomal recessive non-syndromic hearing loss genes in Pakistani individuals as well as the genetic mapping and sequencing approaches used to discover them. Furthermore, we identified enriched gene ontology terms and common pathways involved in these 51 autosomal recessive non-syndromic hearing loss genes to gain a better understanding of the underlying mechanisms. Establishing a molecular understanding of the disorder may aid in reducing its future prevalence by enabling timely diagnostics and genetic counselling, leading to more effective clinical management and treatments of hearing loss.
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Affiliation(s)
- Madiha Shadab
- Department of Zoology, Mirpur University of Science and Technology, Mirpur, Pakistan
| | - Ansar Ahmed Abbasi
- Department of Zoology, Mirpur University of Science and Technology, Mirpur, Pakistan
| | - Ahsan Ejaz
- Department of Physics, University of Kotli Azad Jammu and Kashmir, Kotli, Pakistan
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou, China
| | - Afif Ben-Mahmoud
- Neurological Disorders Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University, Doha, Qatar
| | - Vijay Gupta
- Neurological Disorders Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University, Doha, Qatar
| | - Hyung-Goo Kim
- Neurological Disorders Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University, Doha, Qatar
- College of Health & Life Sciences, Hamad Bin Khalifa University (HBKU), Doha, Qatar
| | - Barbara Vona
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
- Institute for Auditory Neuroscience and Inner Ear Lab, University Medical Center Göttingen, Göttingen, Germany
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3
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Beurg M, Schwalbach ET, Fettiplace R. LHFPL5 is a key element in force transmission from the tip link to the hair cell mechanotransducer channel. Proc Natl Acad Sci U S A 2024; 121:e2318270121. [PMID: 38194445 PMCID: PMC10801851 DOI: 10.1073/pnas.2318270121] [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: 10/19/2023] [Accepted: 11/30/2023] [Indexed: 01/11/2024] Open
Abstract
During auditory transduction, sound-evoked vibrations of the hair cell stereociliary bundles open mechanotransducer (MET) ion channels via tip links extending from one stereocilium to its neighbor. How tension in the tip link is delivered to the channel is not fully understood. The MET channel comprises a pore-forming subunit, transmembrane channel-like protein (TMC1 or TMC2), aided by several accessory proteins, including LHFPL5 (lipoma HMGIC fusion partner-like 5). We investigated the role of LHFPL5 in transduction by comparing MET channel activation in outer hair cells of Lhfpl5-/- knockout mice with those in Lhfpl5+/- heterozygotes. The 10 to 90 percent working range of transduction in Tmc1+/+; Lhfpl5+/- was 52 nm, from which the single-channel gating force, Z, was evaluated as 0.34 pN. However, in Tmc1+/+; Lhfpl5-/- mice, the working range increased to 123 nm and Z more than halved to 0.13 pN, indicating reduced sensitivity. Tip link tension is thought to activate the channel via a gating spring, whose stiffness is inferred from the stiffness change on tip link destruction. The gating stiffness was ~40 percent of the total bundle stiffness in wild type but was virtually abolished in Lhfpl5-/-, implicating LHFPL5 as a principal component of the gating spring. The mutation Tmc1 p.D569N reduced the LHFPL5 immunolabeling in the stereocilia and like Lhfpl5-/- doubled the MET working range, but other deafness mutations had no effect on the dynamic range. We conclude that tip-link tension is transmitted to the channel primarily via LHFPL5; residual activation without LHFPL5 may occur by direct interaction between PCDH15 and TMC1.
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Affiliation(s)
- Maryline Beurg
- Department of Neuroscience, University of WisconsinSchool of Medicine and Public Health, Madison, WI53706
| | - Evan Travis Schwalbach
- Department of Neuroscience, University of WisconsinSchool of Medicine and Public Health, Madison, WI53706
| | - Robert Fettiplace
- Department of Neuroscience, University of WisconsinSchool of Medicine and Public Health, Madison, WI53706
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4
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Jung J, Müller U. Mechanoelectrical transduction-related genetic forms of hearing loss. CURRENT OPINION IN PHYSIOLOGY 2023; 32:100632. [PMID: 36936795 PMCID: PMC10022594 DOI: 10.1016/j.cophys.2023.100632] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Hair cells of the mammalian cochlea are specialized mechanosensory cells that convert mechanical stimuli into electrical signals to initiate the neuronal responses that lead to the perception of sound. The mechanoelectrical transduction (MET) machinery of cochlear hair cells is a multimeric protein complex that consists of the pore forming subunits of the MET channel and several essential accessory subunits that are crucial to regulate channel function and render the channel mechanically sensitive. Mutations have been discovered in the genes that encode all known components of the MET machinery. These mutations cause hearing loss with or without vestibular dysfunction. Some mutations also affect other tissues such as the retina. In this brief review, we will summarize gene mutations that affect the MET machinery of hair cells and how the study of the affected genes has illuminated our understanding of the physiological role of the encoded proteins.
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Affiliation(s)
- Jinsei Jung
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Otorhinolaryngology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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5
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The tetraspan LHFPL5 is critical to establish maximal force sensitivity of the mechanotransduction channel of cochlear hair cells. Cell Rep 2023; 42:112245. [PMID: 36917610 DOI: 10.1016/j.celrep.2023.112245] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/28/2023] [Accepted: 02/27/2023] [Indexed: 03/14/2023] Open
Abstract
The mechanoelectrical transduction (MET) channel of cochlear hair cells is gated by the tip link, but the mechanisms that establish the exquisite force sensitivity of this MET channel are not known. Here, we show that the tetraspan lipoma HMGIC fusion partner-like 5 (LHFPL5) directly couples the tip link to the MET channel. Disruption of these interactions severely perturbs MET. Notably, the N-terminal cytoplasmic domain of LHFPL5 binds to an amphipathic helix in TMC1, a critical gating domain conserved between different MET channels. Mutations in the amphipathic helix of TMC1 or in the N-terminus of LHFPL5 that perturb interactions of LHFPL5 with the amphipathic helix affect channel responses to mechanical force. We conclude that LHFPL5 couples the tip link to the MET channel and that channel gating depends on a structural element in TMC1 that is evolutionarily conserved between MET channels. Overall, our findings support a tether model for transduction channel gating by the tip link.
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6
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Calcium signaling and genetic rare diseases: An auditory perspective. Cell Calcium 2023; 110:102702. [PMID: 36791536 DOI: 10.1016/j.ceca.2023.102702] [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: 12/14/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/07/2023]
Abstract
Deafness is a highly heterogeneous disorder which stems, for 50%, from genetic origins. Sensory transduction relies mainly on sensory hair cells of the cochlea, in the inner ear. Calcium is key for the function of these cells and acts as a fundamental signal transduction. Its homeostasis depends on three factors: the calcium influx, through the mechanotransduction channel at the apical pole of the hair cell as well as the voltage-gated calcium channel at the base of the cells; the calcium buffering via Ca2+-binding proteins in the cytoplasm, but also in organelles such as mitochondria and the reticulum endoplasmic mitochondria-associated membranes with specialized proteins; and the calcium extrusion through the Ca-ATPase pump, located all over the plasma membrane. In addition, the synaptic transmission to the central nervous system is also controlled by calcium. Genetic studies of inherited deafness have tremendously helped understand the underlying molecular pathways of calcium signaling. In this review, we discuss these different factors in light of the associated genetic diseases (syndromic and non-syndromic deafness) and the causative genes.
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7
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Soler DC, Ballesteros A, Sloan AE, McCormick TS, Stepanyan R. Multiple plasma membrane reporters discern LHFPL5 region that blocks trafficking to the plasma membrane. Sci Rep 2023; 13:2528. [PMID: 36781873 PMCID: PMC9925724 DOI: 10.1038/s41598-023-28045-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 01/11/2023] [Indexed: 02/15/2023] Open
Abstract
The mechano-electrical transduction (MET) channel of the inner ear receptor cells, termed hair cells, is a protein complex that enables our senses of hearing and balance. Hair cell MET requires an elaborate interplay of multiple proteins that form the MET channel. One of the MET complex components is the transmembrane protein LHFPL5, which is required for hair cell MET and hearing. LHFPL5 is thought to form a multi-protein complex with other MET channel proteins, such as PCDH15, TMIE, and TMC1. Despite localizing to the plasma membrane of stereocilia, the mechanosensing organelles of hair cells, LHFPL5 requires its binding partner within the MET complex, PCDH15, to localize to the stereocilia tips in hair cells and to the plasma membrane in heterologous cells. Using the Aquaporin 3-tGFP reporter (AGR) for plasma membrane localization, we found that a region within extracellular loop 1, which interacts with PCDH15, precludes the trafficking of AGR reporter to the plasma membrane in heterologous cell lines. Our results suggest that the presence of protein partners may mask endoplasmic reticulum retention regions or enable the proper folding and trafficking of the MET complex components, to facilitate expression of the MET complex at the stereocilia membrane.
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Affiliation(s)
- David C Soler
- Department of Neurosurgery, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.
- Brain Tumor and Neuro-Oncology Center, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.
- University Hospitals-Cleveland Medical Center and the Case Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
| | - Angela Ballesteros
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Andrew E Sloan
- Department of Neurosurgery, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
- Brain Tumor and Neuro-Oncology Center, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
- University Hospitals-Cleveland Medical Center and the Case Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Thomas S McCormick
- Department of Dermatology, Case Western Reserve University, Cleveland, OH, USA
- Murdough Family Center for Psoriasis, University Hospitals Case Medical Center, Cleveland, OH, USA
| | - Ruben Stepanyan
- Department of Otolaryngology - HNS, Case Western Reserve University, Cleveland, OH, USA.
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA.
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8
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Qiu X, Müller U. Sensing sound: Cellular specializations and molecular force sensors. Neuron 2022; 110:3667-3687. [PMID: 36223766 PMCID: PMC9671866 DOI: 10.1016/j.neuron.2022.09.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/03/2022] [Accepted: 09/14/2022] [Indexed: 11/08/2022]
Abstract
Organisms of all phyla express mechanosensitive ion channels with a wide range of physiological functions. In recent years, several classes of mechanically gated ion channels have been identified. Some of these ion channels are intrinsically mechanosensitive. Others depend on accessory proteins to regulate their response to mechanical force. The mechanotransduction machinery of cochlear hair cells provides a particularly striking example of a complex force-sensing machine. This molecular ensemble is embedded into a specialized cellular compartment that is crucial for its function. Notably, mechanotransduction channels of cochlear hair cells are not only critical for auditory perception. They also shape their cellular environment and regulate the development of auditory circuitry. Here, we summarize recent discoveries that have shed light on the composition of the mechanotransduction machinery of cochlear hair cells and how this machinery contributes to the development and function of the auditory system.
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Affiliation(s)
- Xufeng Qiu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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9
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Imtiaz A. ARNSHL gene identification: past, present and future. Mol Genet Genomics 2022; 297:1185-1193. [DOI: 10.1007/s00438-022-01926-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 07/05/2022] [Indexed: 10/16/2022]
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10
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Acharya A, Schrauwen I, Leal SM. Identification of autosomal recessive nonsyndromic hearing impairment genes through the study of consanguineous and non-consanguineous families: past, present, and future. Hum Genet 2022; 141:413-430. [PMID: 34291353 PMCID: PMC10416318 DOI: 10.1007/s00439-021-02309-9] [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: 05/31/2021] [Accepted: 06/24/2021] [Indexed: 10/20/2022]
Abstract
Hearing impairment (HI) is one of the most common sensory disabilities with exceptionally high genetic heterogeneity. Of genetic HI cases, 30% are syndromic and 70% are nonsyndromic. For nonsyndromic (NS) HI, 77% of the cases are due to autosomal recessive (AR) inheritance. ARNSHI is usually congenital/prelingual, severe-to-profound, affects all frequencies and is not progressive. Thus far, 73 ARNSHI genes have been identified. Populations with high rates of consanguinity have been crucial in the identification of ARNSHI genes, and 92% (67/73) of these genes were identified in consanguineous families. Recent changes in genomic technologies and analyses have allowed a shift towards ARNSHI gene discovery in outbred populations. The latter is crucial towards understanding the genetic architecture of ARNSHI in diverse and understudied populations. We present an overview of the 73 ARNSHI genes, the methods used to identify them, including next-generation sequencing which revolutionized the field, and new technologies that show great promise in advancing ARNSHI discoveries.
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Affiliation(s)
- Anushree Acharya
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY, USA
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Isabelle Schrauwen
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY, USA
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Suzanne M Leal
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY, USA.
- Department of Neurology, Columbia University Medical Center, New York, NY, USA.
- Taub Institute for Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA.
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11
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Mechanotransduction in mammalian sensory hair cells. Mol Cell Neurosci 2022; 120:103706. [PMID: 35218890 PMCID: PMC9177625 DOI: 10.1016/j.mcn.2022.103706] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 02/14/2022] [Accepted: 02/18/2022] [Indexed: 11/23/2022] Open
Abstract
In the inner ear, the auditory and vestibular systems detect and translate sensory information regarding sound and balance. The sensory cells that transform mechanical input into an electrical signal in these systems are called hair cells. A specialized organelle on the apical surface of the hair cells called the hair bundle detects the mechanical signals. Displacement of the hair bundle causes mechanotransduction channels to open. The morphology and organization of the hair bundle, as well as the properties and characteristics of the mechanotransduction process, differ between the different hair cell types in the auditory and vestibular systems. These differences likely contribute to maximizing the transduction of specific signals in each system. This review will discuss the molecules essential for mechanotransduction and the properties of the mechanotransduction process, focusing our attention on recent data and differences between the auditory and vestibular systems.
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12
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Liu S, Wang S, Zou L, Xiong W. Mechanisms in cochlear hair cell mechano-electrical transduction for acquisition of sound frequency and intensity. Cell Mol Life Sci 2021; 78:5083-5094. [PMID: 33871677 PMCID: PMC11072359 DOI: 10.1007/s00018-021-03840-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 03/30/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022]
Abstract
Sound signals are acquired and digitized in the cochlea by the hair cells that further transmit the coded information to the central auditory pathways. Any defect in hair cell function may induce problems in the auditory system and hearing-based brain function. In the past 2 decades, our understanding of auditory transduction has been substantially deepened because of advances in molecular, structural, and functional studies. Results from these experiments can be perfectly embedded in the previously established profile from anatomical, histological, genetic, and biophysical research. This review aims to summarize the progress on the molecular and cellular mechanisms of the mechano-electrical transduction (MET) channel in the cochlear hair cells, which is involved in the acquisition of sound frequency and intensity-the two major parameters of an acoustic cue. We also discuss recent studies on TMC1, the molecule likely to form the MET channel pore.
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Affiliation(s)
- Shuang Liu
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
| | - Shufeng Wang
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
| | - Linzhi Zou
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
| | - Wei Xiong
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China.
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China.
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13
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Abstract
Sound-induced mechanical stimuli are detected by elaborate mechanosensory transduction (MT) machinery in highly specialized hair cells of the inner ear. Genetic studies of inherited deafness in the past decades have uncovered several molecular constituents of the MT complex, and intense debate has surrounded the molecular identity of the pore-forming subunits. How the MT components function in concert in response to physical stimulation is not fully understood. In this review, we summarize and discuss multiple lines of evidence supporting the hypothesis that transmembrane channel-like 1 is a long-sought MT channel subunit. We also review specific roles of other components of the MT complex, including protocadherin 15, cadherin 23, lipoma HMGIC fusion partner-like 5, transmembrane inner ear, calcium and integrin-binding family member 2, and ankyrins. Based on these recent advances, we propose a unifying theory of hair cell MT that may reconcile most of the functional discoveries obtained to date. Finally, we discuss key questions that need to be addressed for a comprehensive understanding of hair cell MT at molecular and atomic levels.
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Affiliation(s)
- Wang Zheng
- Departments of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA;
| | - Jeffrey R Holt
- Departments of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA;
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14
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Bankoti K, Generotti C, Hwa T, Wang L, O'Malley BW, Li D. Advances and challenges in adeno-associated viral inner-ear gene therapy for sensorineural hearing loss. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 21:209-236. [PMID: 33850952 PMCID: PMC8010215 DOI: 10.1016/j.omtm.2021.03.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
There is growing attention and effort focused on treating the root cause of sensorineural hearing loss rather than managing associated secondary characteristic features. With recent substantial advances in understanding sensorineural hearing-loss mechanisms, gene delivery has emerged as a promising strategy for the biological treatment of hearing loss associated with genetic dysfunction. There are several successful and promising proof-of-principle examples of transgene deliveries in animal models; however, there remains substantial further progress to be made in these avenues before realizing their clinical application in humans. Herein, we review different aspects of development, ongoing preclinical studies, and challenges to the clinical transition of transgene delivery of the inner ear toward the restoration of lost auditory and vestibular function.
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Affiliation(s)
- Kamakshi Bankoti
- Department of Otorhinolaryngology, Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Charles Generotti
- Department of Otorhinolaryngology, Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tiffany Hwa
- Department of Otorhinolaryngology, Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lili Wang
- Department of Medicine, Gene Therapy Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bert W O'Malley
- Department of Otorhinolaryngology, Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Daqing Li
- Department of Otorhinolaryngology, Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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15
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Deafness mutation D572N of TMC1 destabilizes TMC1 expression by disrupting LHFPL5 binding. Proc Natl Acad Sci U S A 2020; 117:29894-29903. [PMID: 33168709 DOI: 10.1073/pnas.2011147117] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Transmembrane channel-like protein 1 (TMC1) and lipoma HMGIC fusion partner-like 5 (LHFPL5) are recognized as two critical components of the mechanotransduction complex in inner-ear hair cells. However, the physical and functional interactions of TMC1 and LHFPL5 remain largely unexplored. We examined the interaction between TMC1 and LHFPL5 by using multiple approaches, including our recently developed ultrasensitive microbead-based single-molecule pulldown (SiMPull) assay. We demonstrate that LHFPL5 physically interacts with and stabilizes TMC1 in both heterologous expression systems and in the soma and hair bundle of hair cells. Moreover, the semidominant deafness mutation D572N in human TMC1 (D569N in mouse TMC1) severely disrupted LHFPL5 binding and destabilized TMC1 expression. Thus, our findings reveal previously unrecognized physical and functional interactions of TMC1 and LHFPL5 and provide insights into the molecular mechanism by which the D572N mutation causes deafness. Notably, these findings identify a missing link in the currently known physical organization of the mechanotransduction macromolecular complex. Furthermore, this study has demonstrated the power of the microbead-based SiMPull assay for biochemical investigation of rare cells such as hair cells.
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16
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Vona B, Doll J, Hofrichter MAH, Haaf T, Varshney GK. Small fish, big prospects: using zebrafish to unravel the mechanisms of hereditary hearing loss. Hear Res 2020; 397:107906. [PMID: 32063424 PMCID: PMC7415493 DOI: 10.1016/j.heares.2020.107906] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 01/13/2020] [Accepted: 01/29/2020] [Indexed: 12/16/2022]
Abstract
Over the past decade, advancements in high-throughput sequencing have greatly enhanced our knowledge of the mutational signatures responsible for hereditary hearing loss. In its present state, the field has a largely uncensored view of protein coding changes in a growing number of genes that have been associated with hereditary hearing loss, and many more that have been proposed as candidate genes. Sequencing data can now be generated using methods that have become widespread and affordable. The greatest hurdles facing the field concern functional validation of uncharacterized genes and rapid application to human diseases, including hearing and balance disorders. To date, over 30 hearing-related disease models exist in zebrafish. New genome editing technologies, including CRISPR/Cas9 will accelerate the functional validation of hearing loss genes and variants in zebrafish. Here, we discuss current progress in the field and recent advances in genome editing approaches.
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Affiliation(s)
- Barbara Vona
- Department of Otolaryngology--Head & Neck Surgery, Tübingen Hearing Research Centre, Eberhard Karls University Tübingen, Tübingen, Germany.
| | - Julia Doll
- Institute of Human Genetics, Julius Maximilians University, Würzburg, Germany
| | | | - Thomas Haaf
- Institute of Human Genetics, Julius Maximilians University, Würzburg, Germany
| | - Gaurav K Varshney
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States.
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17
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Askew C, Chien WW. Adeno-associated virus gene replacement for recessive inner ear dysfunction: Progress and challenges. Hear Res 2020; 394:107947. [PMID: 32247629 PMCID: PMC7939749 DOI: 10.1016/j.heares.2020.107947] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 03/02/2020] [Accepted: 03/04/2020] [Indexed: 01/08/2023]
Abstract
Approximately 3 in 1000 children in the US under 4 years of age are affected by hearing loss. Currently, cochlear implants represent the only line of treatment for patients with severe to profound hearing loss, and there are no targeted drug or biological based therapies available. Gene replacement is a promising therapeutic approach for hereditary hearing loss, where viral vectors are used to deliver functional cDNA to "replace" defective genes in dysfunctional cells in the inner ear. Proof-of-concept studies have successfully used this approach to improve auditory function in mouse models of hereditary hearing loss, and human clinical trials are on the immediate horizon. The success of this method is ultimately determined by the underlying biology of the defective gene and design of the treatment strategy, relying on intervention before degeneration of the sensory structures occurs. A challenge will be the delivery of a corrective gene to the proper target within the therapeutic window of opportunity, which may be unique for each specific defective gene. Although rescue of pre-lingual forms of recessive deafness have been explored in animal models thus far, future identification of genes with post-lingual onset that are amenable to gene replacement holds even greater promise for treatment, since the therapeutic window is likely open for a much longer period of time. This review summarizes the current state of adeno-associated virus (AAV) gene replacement therapy for recessive hereditary hearing loss and discusses potential challenges and opportunities for translating inner ear gene replacement therapy for patients with hereditary hearing loss.
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Affiliation(s)
- Charles Askew
- Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Wade W Chien
- Inner Ear Gene Therapy Program, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health, Bethesda, MD, USA; Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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18
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Fetal gene therapy and pharmacotherapy to treat congenital hearing loss and vestibular dysfunction. Hear Res 2020; 394:107931. [PMID: 32173115 DOI: 10.1016/j.heares.2020.107931] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 12/23/2022]
Abstract
Disabling hearing loss is expected to affect over 900 million people worldwide by 2050. The World Health Organization estimates that the annual economic impact of hearing loss globally is US$ 750 billion. The inability to hear may complicate effective interpersonal communication and negatively impact personal and professional relationships. Recent advances in the genetic diagnosis of inner ear disease have keenly focused attention on strategies to restore hearing and balance in individuals with defined gene mutations. Mouse models of human hearing loss serve as the primary approach to test gene therapies and pharmacotherapies. The goal of this review is to articulate the rationale for fetal gene therapy and pharmacotherapy to treat congenital hearing loss and vestibular dysfunction. The differential onset of hearing in mice and humans suggests that a prenatal window of therapeutic efficacy in humans may be optimal to restore sensory function. Mouse studies demonstrating the utility of early fetal intervention in the inner ear show promise. We focus on the modulation of gene expression through two strategies that have successfully treated deafness in animal models and have had clinical success for other conditions in humans: gene replacement and antisense oligonucleotide-mediated modulation of gene expression. The recent establishment of effective therapies targeting the juvenile and adult mouse provide informative counterexamples where intervention in the maturing and fully functional mouse inner ear may be effective. Distillation of the current literature leads to the conclusion that novel therapeutic strategies to treat genetic deafness and imbalance will soon translate to clinical trials.
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19
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Erickson T, Pacentine IV, Venuto A, Clemens R, Nicolson T. The lhfpl5 Ohnologs lhfpl5a and lhfpl5b Are Required for Mechanotransduction in Distinct Populations of Sensory Hair Cells in Zebrafish. Front Mol Neurosci 2020; 12:320. [PMID: 32009898 PMCID: PMC6974483 DOI: 10.3389/fnmol.2019.00320] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/16/2019] [Indexed: 01/20/2023] Open
Abstract
Hair cells sense and transmit auditory, vestibular, and hydrodynamic information by converting mechanical stimuli into electrical signals. This process of mechano-electrical transduction (MET) requires a mechanically gated channel localized in the apical stereocilia of hair cells. In mice, lipoma HMGIC fusion partner-like 5 (LHFPL5) acts as an auxiliary subunit of the MET channel whose primary role is to correctly localize PCDH15 and TMC1 to the mechanotransduction complex. Zebrafish have two lhfpl5 genes (lhfpl5a and lhfpl5b), but their individual contributions to MET channel assembly and function have not been analyzed. Here we show that the zebrafish lhfpl5 genes are expressed in discrete populations of hair cells: lhfpl5a expression is restricted to auditory and vestibular hair cells in the inner ear, while lhfpl5b expression is specific to hair cells of the lateral line organ. Consequently, lhfpl5a mutants exhibit defects in auditory and vestibular function, while disruption of lhfpl5b affects hair cells only in the lateral line neuromasts. In contrast to previous reports in mice, localization of Tmc1 does not depend upon Lhfpl5 function in either the inner ear or lateral line organ. In both lhfpl5a and lhfpl5b mutants, GFP-tagged Tmc1 and Tmc2b proteins still localize to the stereocilia of hair cells. Using a stably integrated GFP-Lhfpl5a transgene, we show that the tip link cadherins Pcdh15a and Cdh23, along with the Myo7aa motor protein, are required for correct Lhfpl5a localization at the tips of stereocilia. Our work corroborates the evolutionarily conserved co-dependence between Lhfpl5 and Pcdh15, but also reveals novel requirements for Cdh23 and Myo7aa to correctly localize Lhfpl5a. In addition, our data suggest that targeting of Tmc1 and Tmc2b proteins to stereocilia in zebrafish hair cells occurs independently of Lhfpl5 proteins.
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Affiliation(s)
- Timothy Erickson
- Department of Biology, East Carolina University, Greenville, NC, United States.,Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR, United States
| | - Itallia V Pacentine
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR, United States
| | - Alexandra Venuto
- Department of Biology, East Carolina University, Greenville, NC, United States
| | - Rachel Clemens
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR, United States
| | - Teresa Nicolson
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR, United States
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20
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Noman M, Ishaq R, Bukhari SA, Ahmed ZM, Riazuddin S. Delineation of Homozygous Variants Associated with Prelingual Sensorineural Hearing Loss in Pakistani Families. Genes (Basel) 2019; 10:genes10121031. [PMID: 31835641 PMCID: PMC6947215 DOI: 10.3390/genes10121031] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 11/26/2019] [Accepted: 12/03/2019] [Indexed: 12/30/2022] Open
Abstract
Hearing loss is a genetically heterogeneous disorder affecting approximately 360 million people worldwide and is among the most common sensorineural disorders. Here, we report a genetic analysis of seven large consanguineous families segregating prelingual sensorineural hearing loss. Whole-exome sequencing (WES) revealed seven different pathogenic variants segregating with hearing loss in these families, three novel variants (c.1204G>A, c.322G>T, and c.5587C>T) in TMPRSS3, ESRRB, and OTOF, and four previously reported variants (c.208C>T, c.6371G>A, c.226G>A, and c.494C>T) in LRTOMT, MYO15A, KCNE1, and LHFPL5, respectively. All identified variants had very low frequencies in the control databases and were predicted to have pathogenic effects on the encoded proteins. In addition to being familial, we also found intersibship locus heterogeneity in the evaluated families. The known pathogenic c.226C>T variant identified in KCNE1 only segregates with the hearing loss phenotype in a subset of affected members of the family GCNF21. This study further highlights the challenges of identifying disease-causing variants for highly heterogeneous disorders and reports the identification of three novel and four previously reported variants in seven known deafness genes.
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Affiliation(s)
- Muhammad Noman
- Department of Biochemistry, Government College University, Faisalabad 38000, Pakistan
| | - Rafaqat Ishaq
- Department of Otorhinolaryngology Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- University Institute of Biochemistry & Biotechnology, PMAS-Arid Agriculture University, Rawalpindi 46000, Pakistan
| | - Shazia A. Bukhari
- Department of Biochemistry, Government College University, Faisalabad 38000, Pakistan
| | - Zubair M. Ahmed
- Department of Biochemistry, Government College University, Faisalabad 38000, Pakistan
- Department of Otorhinolaryngology Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Correspondence: (Z.M.A); (S.R.)
| | - Saima Riazuddin
- Department of Otorhinolaryngology Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Correspondence: (Z.M.A); (S.R.)
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21
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Jia Y, Zhao Y, Kusakizako T, Wang Y, Pan C, Zhang Y, Nureki O, Hattori M, Yan Z. TMC1 and TMC2 Proteins Are Pore-Forming Subunits of Mechanosensitive Ion Channels. Neuron 2019; 105:310-321.e3. [PMID: 31761710 DOI: 10.1016/j.neuron.2019.10.017] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 09/05/2019] [Accepted: 10/09/2019] [Indexed: 11/28/2022]
Abstract
Transmembrane channel-like (TMC) 1 and 2 are required for the mechanotransduction of mouse inner ear hair cells and localize to the site of mechanotransduction in mouse hair cell stereocilia. However, it remains unclear whether TMC1 and TMC2 are indeed ion channels and whether they can sense mechanical force directly. Here we express TMC1 from the green sea turtle (CmTMC1) and TMC2 from the budgerigar (MuTMC2) in insect cells, purify and reconstitute the proteins, and show that liposome-reconstituted CmTMC1 and MuTMC2 proteins possess ion channel activity. Furthermore, by applying pressure to proteoliposomes, we demonstrate that both CmTMC1 and MuTMC2 proteins can indeed respond to mechanical stimuli. In addition, CmTMC1 mutants corresponding to human hearing loss mutants exhibit reduced or no ion channel activity. Taken together, our results show that the CmTMC1 and MuTMC2 proteins are pore-forming subunits of mechanosensitive ion channels, supporting TMC1 and TMC2 as hair cell transduction channels.
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Affiliation(s)
- Yanyan Jia
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurosurgery at Huashan Hospital, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Yimeng Zhao
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute for Complex Systems, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Tsukasa Kusakizako
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yao Wang
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute for Complex Systems, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Chengfang Pan
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurosurgery at Huashan Hospital, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Yuwei Zhang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurosurgery at Huashan Hospital, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Motoyuki Hattori
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute for Complex Systems, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China.
| | - Zhiqiang Yan
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurosurgery at Huashan Hospital, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai 200438, China.
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22
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Cunningham CL, Müller U. Molecular Structure of the Hair Cell Mechanoelectrical Transduction Complex. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033167. [PMID: 30082452 DOI: 10.1101/cshperspect.a033167] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cochlear hair cells employ mechanically gated ion channels located in stereocilia that open in response to sound wave-induced motion of the basilar membrane, converting mechanical stimulation to graded changes in hair cell membrane potential. Membrane potential changes in hair cells cause neurotransmitter release from hair cells that initiate electrical signals in the nerve terminals of afferent fibers from spiral ganglion neurons. These signals are then propagated within the central nervous system (CNS) to mediate the sensation of hearing. Recent studies show that the mechanoelectrical transduction (MET) machinery of hair cells is formed by an ensemble of proteins. Candidate components forming the MET channel have been identified, but none alone fulfills all criteria necessary to define them as pore-forming subunits of the MET channel. We will review here recent findings on the identification and function of proteins that are components of the MET machinery in hair cells and consider remaining open questions.
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Affiliation(s)
- Christopher L Cunningham
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, Maryland 21205
| | - Ulrich Müller
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, Maryland 21205
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23
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Richard EM, Santos-Cortez RLP, Faridi R, Rehman AU, Lee K, Shahzad M, Acharya A, Khan AA, Imtiaz A, Chakchouk I, Takla C, Abbe I, Rafeeq M, Liaqat K, Chaudhry T, Bamshad MJ, Schrauwen I, Khan SN, Morell RJ, Zafar S, Ansar M, Ahmed ZM, Ahmad W, Riazuddin S, Friedman TB, Leal SM, Riazuddin S. Global genetic insight contributed by consanguineous Pakistani families segregating hearing loss. Hum Mutat 2019; 40:53-72. [PMID: 30303587 PMCID: PMC6296877 DOI: 10.1002/humu.23666] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/04/2018] [Accepted: 10/07/2018] [Indexed: 12/14/2022]
Abstract
Consanguineous Pakistani pedigrees segregating deafness have contributed decisively to the discovery of 31 of the 68 genes associated with nonsyndromic autosomal recessive hearing loss (HL) worldwide. In this study, we utilized genome-wide genotyping, Sanger and exome sequencing to identify 163 DNA variants in 41 previously reported HL genes segregating in 321 Pakistani families. Of these, 70 (42.9%) variants identified in 29 genes are novel. As expected from genetic studies of disorders segregating in consanguineous families, the majority of affected individuals (94.4%) are homozygous for HL-associated variants, with the other variants being compound heterozygotes. The five most common HL genes in the Pakistani population are SLC26A4, MYO7A, GJB2, CIB2 and HGF, respectively. Our study provides a profile of the genetic etiology of HL in Pakistani families, which will allow for the development of more efficient genetic diagnostic tools, aid in accurate genetic counseling, and guide application of future gene-based therapies. These findings are also valuable in interpreting pathogenicity of variants that are potentially associated with HL in individuals of all ancestries. The Pakistani population, and its infrastructure for studying human genetics, will continue to be valuable to gene discovery for HL and other inherited disorders.
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Affiliation(s)
- Elodie M. Richard
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, 21201, USA
| | - Regie LP. Santos-Cortez
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Rabia Faridi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
- National Center for Excellence in Molecular Biology, University of the Punjab, Lahore 53700, Pakistan
| | - Atteeq U. Rehman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Kwanghyuk Lee
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Mohsin Shahzad
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, 21201, USA
- Shaheed Zulfiqar Ali Bhutto Medical University, Pakistan Institute of Medical Sciences, Islamabad, 44000, Pakistan
| | - Anushree Acharya
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Asma A. Khan
- National Center for Excellence in Molecular Biology, University of the Punjab, Lahore 53700, Pakistan
| | - Ayesha Imtiaz
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Imen Chakchouk
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Christina Takla
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Izoduwa Abbe
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Maria Rafeeq
- National Center for Excellence in Molecular Biology, University of the Punjab, Lahore 53700, Pakistan
| | - Khurram Liaqat
- Department of Biotechnology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Taimur Chaudhry
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Michael J. Bamshad
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | | | - Isabelle Schrauwen
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Shaheen N. Khan
- National Center for Excellence in Molecular Biology, University of the Punjab, Lahore 53700, Pakistan
| | - Robert J. Morell
- The Genomics and Computational Biology Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892
| | - Saba Zafar
- Institute of Molecular Biology and Biotechnology, Bahauddin Zakariya University, Multan, 59300, Pakistan
| | - Muhammad Ansar
- Department of Biotechnology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Zubair M. Ahmed
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, 21201, USA
| | - Wasim Ahmad
- Department of Biotechnology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Sheik Riazuddin
- Shaheed Zulfiqar Ali Bhutto Medical University, Pakistan Institute of Medical Sciences, Islamabad, 44000, Pakistan
- Allama Iqbal Medical College, University of Health Sciences, Lahore, 54500, Pakistan
| | - Thomas B. Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Suzanne M. Leal
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Saima Riazuddin
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, 21201, USA
- Shaheed Zulfiqar Ali Bhutto Medical University, Pakistan Institute of Medical Sciences, Islamabad, 44000, Pakistan
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24
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Carpena NT, Lee MY. Genetic Hearing Loss and Gene Therapy. Genomics Inform 2018; 16:e20. [PMID: 30602081 PMCID: PMC6440668 DOI: 10.5808/gi.2018.16.4.e20] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 12/04/2018] [Indexed: 12/15/2022] Open
Abstract
Genetic hearing loss crosses almost all the categories of hearing loss which includes the following: conductive, sensory, and neural; syndromic and nonsyndromic; congenital, progressive, and adult onset; high-frequency, low-frequency, or mixed frequency; mild or profound; and recessive, dominant, or sex-linked. Genes play a role in almost half of all cases of hearing loss but effective treatment options are very limited. Genetic hearing loss is considered to be extremely genetically heterogeneous. The advancements in genomics have been instrumental to the identification of more than 6,000 causative variants in more than 150 genes causing hearing loss. Identification of genes for hearing impairment provides an increased insight into the normal development and function of cells in the auditory system. These defective genes will ultimately be important therapeutic targets. However, the auditory system is extremely complex which requires tremendous advances in gene therapy including gene vectors, routes of administration, and therapeutic approaches. This review summarizes and discusses recent advances in elucidating the genomics of genetic hearing loss and technologies aimed at developing a gene therapy that may become a treatment option for in the near future.
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Affiliation(s)
- Nathanial T Carpena
- Department of Otolaryngology-Head and Neck Surgery, Dankook University College of Medicine, Cheonan 31116, Korea
| | - Min Young Lee
- Department of Otolaryngology-Head and Neck Surgery, Dankook University College of Medicine, Cheonan 31116, Korea.,Beckman Laser Institute Korea, Dankook University, Cheonan 31116, Korea
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25
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Al-Amri AH, Al Saegh A, Al-Mamari W, El-Asrag ME, Al-Kindi MN, Al Khabouri M, Al Wardy N, Al Lamki K, Gabr A, Idris A, Inglehearn CF, Clapcote SJ, Ali M. LHFPL5 mutation: A rare cause of non-syndromic autosomal recessive hearing loss. Eur J Med Genet 2018; 62:103592. [PMID: 30476627 DOI: 10.1016/j.ejmg.2018.11.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 07/30/2018] [Accepted: 11/22/2018] [Indexed: 11/18/2022]
Abstract
Hearing loss is a debilitating disorder that impairs language acquisition, resulting in disability in children and potential isolation in adulthood. Its onset can have a genetic basis, though environmental factors, which are often preventable, can also cause the condition. The genetic forms are highly heterogeneous, and early detection is necessary to arrange appropriate patient support. Here we report the molecular basis of hereditary hearing loss in a consanguineous family with multiple affected members from Oman. Combining homozygosity mapping with whole exome sequencing identified a novel homozygous nucleotide substitution c.575T > C in the lipoma HMGIC fusion partner-like 5 gene (LHFPL5), that converted the 192nd amino acid residue in the protein from a leucine to a proline, p.(Leu192Pro). Sanger sequencing confirmed segregation with the disease phenotype as expected for a recessive condition and the variant was absent in 123,490 subjects from various disease-specific and population genetic studies as well as 150 unrelated individuals and 35 deaf patients of Omani ethnicity. This study, which describes a novel LHFPL5 mutation in a family of Omani origin with hereditary hearing loss, supports previous clinical descriptions of the condition and contributes to the genetic spectrum of mutations in this form of deafness.
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Affiliation(s)
- Ahmed H Al-Amri
- Section of Ophthalmology & Neuroscience, Leeds Institute of Medical Research at St. James's, University of Leeds, United Kingdom; School of Biomedical Sciences, University of Leeds, United Kingdom; National Genetic Centre, Directorate General of Royal Hospital, Ministry of Health, Muscat, Oman
| | - Abeer Al Saegh
- Genetic & Developmental Medicine Clinic, Genetics Department, Sultan Qaboos University Hospital, Muscat, Oman
| | - Watfa Al-Mamari
- Developmental Pediatric Unit, Child Health Department, Sultan Qaboos University Hospital, Muscat, Oman
| | - Mohammed E El-Asrag
- Section of Ophthalmology & Neuroscience, Leeds Institute of Medical Research at St. James's, University of Leeds, United Kingdom; Department of Zoology, Faculty of Science, Benha University, Benha, Egypt
| | | | - Mazin Al Khabouri
- Department of Ear, Nose & Throat, Al Nahdha Hospital, Ministry of Health, Muscat, Oman
| | - Nadia Al Wardy
- Biochemistry Department, Sultan Qaboos University Hospital, Muscat, Oman
| | - Khalsa Al Lamki
- Biochemistry Department, Sultan Qaboos University Hospital, Muscat, Oman
| | - Ahlam Gabr
- Developmental Pediatric Unit, Child Health Department, Sultan Qaboos University Hospital, Muscat, Oman
| | - Ahmed Idris
- Developmental Pediatric Unit, Child Health Department, Sultan Qaboos University Hospital, Muscat, Oman
| | - Chris F Inglehearn
- Section of Ophthalmology & Neuroscience, Leeds Institute of Medical Research at St. James's, University of Leeds, United Kingdom
| | | | - Manir Ali
- Section of Ophthalmology & Neuroscience, Leeds Institute of Medical Research at St. James's, University of Leeds, United Kingdom.
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Liaqat K, Chiu I, Lee K, Chakchouk I, Andrade-Elizondo PB, Santos-Cortez RLP, Hussain S, Nawaz S, Ansar M, Khan MN, Basit S, Schrauwen I, Ahmad W, Leal SM. Novel missense and 3'-UTR splice site variants in LHFPL5 cause autosomal recessive nonsyndromic hearing impairment. J Hum Genet 2018; 63:1099-1107. [PMID: 30177809 PMCID: PMC6202120 DOI: 10.1038/s10038-018-0502-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/08/2018] [Accepted: 08/09/2018] [Indexed: 02/07/2023]
Abstract
LHFPL5, the gene for DFNB67, underlies autosomal recessive nonsyndromic hearing impairment. We identified seven Pakistani families that mapped to 6p21.31, which includes the LHFPL5 gene. Sanger sequencing of LHFPL5 using DNA samples from hearing impaired and unaffected members of these seven families identified four variants. Among the identified variants, two were novel: one missense c.452 G > T (p.Gly151Val) and one splice site variant (c.*16 + 1 G > A) were each identified in two families. Two known variants: c.250delC (p.Leu84*) and c.380 A > G (p.Tyr127Cys) were also observed in two families and a single family, respectively. Nucleotides c.452G and c.*16 + 1G and amino-acid residue p.Gly151 are under strong evolutionary conservation. In silico bioinformatics analyses predicted these variants to be damaging. The splice site variant (c.*16 + 1 G > A) is predicted to affect pre-mRNA splicing and a loss of the 5' donor splice site in the 3'-untranslated region (3'-UTR). Further analysis supports the activation of a cryptic splice site approximately 357-bp downstream, leading to an extended 3'-UTR with additional regulatory motifs. In conclusion, we identified two novel variants in LHFPL5, including a unique 3'-UTR splice site variant that is predicted to impact pre-mRNA splicing and regulation through an extended 3'-UTR.
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Affiliation(s)
- Khurram Liaqat
- Department of Biotechnology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Ilene Chiu
- Bobby R Alford Department of Otolaryngology-Head and Neck Surgery, Baylor College of Medicine, Houston, TX, USA
| | - Kwanghyuk Lee
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Imen Chakchouk
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Paula B Andrade-Elizondo
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Regie Lyn P Santos-Cortez
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Shabir Hussain
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Shoaib Nawaz
- Department of Biotechnology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Muhammad Ansar
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Muhammad Nasim Khan
- Department of Zoology, University of Azad Jammu and Kashmir, Muzaffarabad, Pakistan
| | - Sulman Basit
- Center for Genetics and Inherited Diseases, Taibah University, Almadinah Almunawwarah, Saudi Arabia
| | - Isabelle Schrauwen
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Wasim Ahmad
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Suzanne M Leal
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
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Lerat J, Bonnet C, Cartault F, Loundon N, Jacquemont ML, Darcel F, Rouillon I, Mezouaghi K, Guichet A, Litzler J, Gesny R, Gherbi S, Aissa IB, Digeon FSJ, Garabedian EN, Bonnefont JP, Genin E, Denoyelle F, Jonard L, Marlin S. High prevalence of congenital deafness on Reunion Island is due to a founder variant of LHFPL5. Clin Genet 2018; 95:177-181. [PMID: 30298622 DOI: 10.1111/cge.13460] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/02/2018] [Accepted: 10/03/2018] [Indexed: 11/28/2022]
Abstract
Reunion Island is a French oversea department in the Indian Ocean with 1.6/1000, an estimated prevalence of deafness that is almost double as compared to the mainland France. Twelve children having isolated bilateral prelingual profound deafness along with motor delay attributed to vestibular areflexia were enrolled. Their mean walking age was 19 months. Electroretinography and temporal bone CT-scans were normal in all cases. A novel homozygous frameshift lipoma HMGIC fusion partner-like 5 (LHFPL5) variant c.185delT p.(Phe62Serfs*23) was identified using whole-exome sequencing. It was found in seven families. Four patients from two different families from both Reunion Island and mainland France, were compound heterozygous: c.185delT p.(Phe62Serfs*23) and c.472C > T p.(Arg158Trp). The phenotype observed in our patients completely mimics the hurry-scurry (hscy) murine Tmhs knock-out model. The recurrent occurrence of same LHFPL5 variant in Reunion Island is attributed to common ancestor couple born in 1693.
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Affiliation(s)
- Justine Lerat
- INSERM UMR_S1163 IHU Imagine - Institut des Maladies Génétiques - Université Paris Descartes, Paris, France.,Génétique Moléculaire, Necker, AP-HP, Paris, France.,Otorhinolaryngologie, CHU, Limoges, France
| | - Crystel Bonnet
- Institut de la Vision, UMRS 1120 INSERM/UPMC, Paris, France
| | - François Cartault
- Génétique Moléculaire, CHU La Réunion site Felix Guyon, Paris, France
| | - Natalie Loundon
- Centre de Référence Maladies Rares, Surdités Génétiques, Necker, AP-HP, Paris, France.,Otorhinolaryngologie Pédiatrique, Necker, AP-HP, Paris, France
| | | | | | - Isabelle Rouillon
- Centre de Référence Maladies Rares, Surdités Génétiques, Necker, AP-HP, Paris, France.,Otorhinolaryngologie Pédiatrique, Necker, AP-HP, Paris, France
| | - Kheira Mezouaghi
- Centre Régional de Compétences en Surdité Infantile, Sainte-Clothilde, France
| | | | | | | | - Souad Gherbi
- Centre de Référence Maladies Rares, Surdités Génétiques, Necker, AP-HP, Paris, France
| | - Ines Ben Aissa
- Centre de Référence Maladies Rares, Surdités Génétiques, Necker, AP-HP, Paris, France
| | | | - Eréa-Nöel Garabedian
- Centre de Référence Maladies Rares, Surdités Génétiques, Necker, AP-HP, Paris, France.,Otorhinolaryngologie Pédiatrique, Necker, AP-HP, Paris, France
| | | | - Emmanuelle Genin
- UMR1078 Génétique, Génomique Fonctionnelle et Biotechnologies, Inserm, Université de Brest, CHU Brest, France
| | - Françoise Denoyelle
- Centre de Référence Maladies Rares, Surdités Génétiques, Necker, AP-HP, Paris, France.,Otorhinolaryngologie Pédiatrique, Necker, AP-HP, Paris, France
| | - Laurence Jonard
- Génétique Moléculaire, Necker, AP-HP, Paris, France.,Centre de Référence Maladies Rares, Surdités Génétiques, Necker, AP-HP, Paris, France
| | - Sandrine Marlin
- INSERM UMR_S1163 IHU Imagine - Institut des Maladies Génétiques - Université Paris Descartes, Paris, France.,Centre de Référence Maladies Rares, Surdités Génétiques, Necker, AP-HP, Paris, France
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28
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Wang L, Kempton JB, Brigande JV. Gene Therapy in Mouse Models of Deafness and Balance Dysfunction. Front Mol Neurosci 2018; 11:300. [PMID: 30210291 PMCID: PMC6123355 DOI: 10.3389/fnmol.2018.00300] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 08/06/2018] [Indexed: 12/16/2022] Open
Abstract
Therapeutic strategies to restore hearing and balance in mouse models of inner ear disease aim to rescue sensory function by gene replacement, augmentation, knock down or knock out. Modalities to achieve therapeutic effects have utilized virus-mediated transfer of wild type genes and small interfering ribonucleic acids; systemic and focal administration of antisense oligonucleotides (ASO) and designer small molecules; and lipid-mediated transfer of Cas 9 ribonucleoprotein (RNP) complexes. This work has established that gene or drug administration to the structurally and functionally immature, early neonatal mouse inner ear prior to hearing onset is a prerequisite for the most robust therapeutic responses. These observations may have significant implications for translating mouse inner ear gene therapies to patients. The human fetus hears by gestational week 19, suggesting that a corollary window of therapeutic efficacy closes early in the second trimester of pregnancy. We hypothesize that fetal therapeutics deployed prior to hearing onset may be the most effective approach to preemptively manage genetic mutations that cause deafness and vestibular dysfunction. We assert that gene therapy studies in higher vertebrate model systems with fetal hearing onset and a comparable acoustic range and sensitivity to that of humans are an essential step to safely and effectively translate murine gene therapies to the clinic.
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Affiliation(s)
- Lingyan Wang
- Oregon Hearing Research Center, Department of Otolaryngology, Oregon Health & Science University, Portland, OR, United States
| | - J Beth Kempton
- Oregon Hearing Research Center, Department of Otolaryngology, Oregon Health & Science University, Portland, OR, United States
| | - John V Brigande
- Oregon Hearing Research Center, Department of Otolaryngology, Oregon Health & Science University, Portland, OR, United States
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29
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Lu Y, Zhou D, King R, Zhu S, Simpson CL, Jones BC, Zhang W, Geisert EE, Lu L. The genetic dissection of Myo7a gene expression in the retinas of BXD mice. Mol Vis 2018; 24:115-126. [PMID: 29430167 PMCID: PMC5802760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 01/31/2018] [Indexed: 11/16/2022] Open
Abstract
Purpose Usher syndrome (US) is characterized by a loss of vision due to retinitis pigmentosa (RP) and deafness. US has three clinical subtypes, but even within each subtype, the severity varies. Myosin VIIA, coded by Myo7a, has been identified as one of the causal genes of US. This study aims to identify pathways and other genes through which Myo7a interacts to affect the presentation of US symptoms. Methods In this study, we used the retinal tissue of BXD recombinant inbred (RI) mice to examine the expression of Myo7a and perform genetic mapping. Expression quantitative trait locus (eQTL), single nucleotide polymorphism (SNP), and gene correlation analysis were performed using GeneNetwork. Gene set enrichment analysis was performed using WebGestalt, and gene network construction was performed using the Gene Cohesion Analysis Tool. Results We found Myo7a to be cis-regulated, with varied levels of expression across BXD strains. Here, we propose a genetic network with 40 genes whose expression is highly correlated with Myo7a. Among these genes, six have been linked to retinal diseases, three to deafness, and five share a transcription factor with Myo7a. Gene ontology and pathway analysis revealed a strong connection among ion channel activity, Myo7a, and US. Conclusions Although Myo7a is a causal gene of US type I, this gene works with many other genes and pathways to affect the severity of US. Many of the genes found in the genetic network, pathways, and gene ontology categories of Myo7a are related to either deafness or blindness. Further investigation is needed to examine the specific relationships between these genes, which may assist in the treatment of US.
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Affiliation(s)
- Ye Lu
- Department of Ophthalmology, The First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou, China
| | - Diana Zhou
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Rebecca King
- Department of Ophthalmology and Emory Eye Center, Emory University, Atlanta, GA
| | - Shuang Zhu
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, TX
| | - Claire L. Simpson
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Byron C. Jones
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Wenbo Zhang
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, TX
| | - Eldon E. Geisert
- Department of Ophthalmology and Emory Eye Center, Emory University, Atlanta, GA
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
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30
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Corey DP, Ó Maoiléidigh D, Ashmore JF. Mechanical Transduction Processes in the Hair Cell. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/978-3-319-52073-5_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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Subaşıoğlu A, Duman D, Sırmacı A, Bademci G, Carkıt F, Somdaş MA, Erkan M, Tekin M, Dündar M. Research of genetic bases of hereditary non-syndromic hearing loss. Turk Arch Pediatr 2017; 52:122-132. [PMID: 29062245 DOI: 10.5152/turkpediatriars.2017.4254] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 03/13/2017] [Indexed: 11/22/2022]
Abstract
AIM Hearing loss is the most common sensory disorder that affects approximately one per 1000 live births. With this project, we aimed to identify gene variants that were common causes of hearing loss in Turkey to contribute to the planning of genetic screening programs for hearing loss, as well as to improve genetic counseling to affected families. MATERIAL AND METHODS Twenty-one families with at least two affected individuals and parental consanguinity who presented with non-syndromic severe-to-profound sensorineural hearing loss were included in this study. We first screened for mutations in GJB2 and mitochondrial DNA 12S RNA genes. Subsequently, we genotyped the TMIE c.250C>T and SNP markers flanking the SLC26A4, MYO7A, MYO15A, OTOF, CDH23, TMIE, TECTA, PCDH15, TMC1, TMPRSS3, TMHS genes in the remaining twelve families without mutations in GJB2. RESULTS Screening for mutations in GJB2 gene showed c.[35delG];[35delG] mutation in four families, c.[35delG];[507C>A] mutation in two families, c.[35delG];[-23+1G>A] mutation in one family, and c.457G>A heterozygous mutation in one family. Genotyping SNP markers showed the c.[250C>T];[250C>T] mutation in TMIE in one family. A homozygous region with SNP genotypes was detected with the OTOF gene in one family, the TMPRSS3 gene in another family, and also a homozygous region was detected with TMHS, OTOF, and TMPRSS3 genes in another family. CONCLUSIONS Further research will be required to determine the genetic bases of hearing loss in families with non-syndromic hearing loss.
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Affiliation(s)
- Aslı Subaşıoğlu
- Department of Medical Genetics, Erciyes University Faculty of Medicine, Kayseri, Turkey
| | - Duygu Duman
- Department of Pediatrics, Division of Pediatric Genetic Diseases, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Aslı Sırmacı
- Division of Human Genetics, John T. Macdonald, Miami University Miller Medical Faculty, Miami, USA
| | - Güney Bademci
- Division of Human Genetics, John T. Macdonald, Miami University Miller Medical Faculty, Miami, USA
| | - Fehime Carkıt
- Division of Odiology, Kayseri Education and Research Hospital, Kayseri, Turkey
| | - Mehmet Akif Somdaş
- Department of Otolaryngology, Erciyes University Faculty of Medicine, Kayseri, Turkey
| | - Mustafa Erkan
- Department of Otolaryngology, Erciyes University Faculty of Medicine, Kayseri, Turkey
| | - Mustafa Tekin
- Division of Human Genetics, John T. Macdonald, Miami University Miller Medical Faculty, Miami, USA
| | - Munis Dündar
- Department of Medical Genetics, Erciyes University Faculty of Medicine, Kayseri, Turkey
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Wang R, Han S, Khan A, Zhang X. Molecular Analysis of Twelve Pakistani Families with Nonsyndromic or Syndromic Hearing Loss. Genet Test Mol Biomarkers 2017; 21:316-321. [PMID: 28281779 DOI: 10.1089/gtmb.2016.0328] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
AIM To investigate the causative genetic mutations in 12 Pakistani families with nonsyndromic or syndromic hearing loss. METHODS Mutations in the most common causative gene for hearing loss, GJB2, were evaluated by Sanger sequencing. Targeted next-generation sequencing or whole-exome sequencing was used to analyze the genomic DNA samples from 11 probands with hearing loss. Sanger sequencing was performed to verify all identified variants. RESULTS We found pathogenic, or likely to be pathogenic, mutations in all 12 families, including six known mutations in GJB2, SLC26A4, LHFPL5, and USH2A and eight novel mutations in ESPN, MYO7A, LRTOMT, PCDH15, USH2A, or EPS8L2. Notably, four compound heterozygous mutations in the MYO7A and USH2A genes were detected in two consanguineous families. In addition, the novel frameshift mutation in EPS8L2 was first documented in Pakistan. CONCLUSIONS Our study increases the spectrum of mutations associated with hearing loss in the Pakistani population. In addition, our study highlights the fact that compound heterozygous mutations, although rare, can occur in consanguineous families.
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Affiliation(s)
- Rongrong Wang
- 1 Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, McKusick-Zhang Center for Genetic Medicine, School of Basic Medicine Peking Union Medical College , Beijing, China
| | - Shirui Han
- 2 The Research Center for Medical Genomics, China Medical University , Shenyang, China
| | - Amjad Khan
- 2 The Research Center for Medical Genomics, China Medical University , Shenyang, China
| | - Xue Zhang
- 1 Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, McKusick-Zhang Center for Genetic Medicine, School of Basic Medicine Peking Union Medical College , Beijing, China
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Laser-capture micro dissection combined with next-generation sequencing analysis of cell type-specific deafness gene expression in the mouse cochlea. Hear Res 2017; 348:87-97. [PMID: 28263850 DOI: 10.1016/j.heares.2017.02.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 12/25/2016] [Accepted: 02/28/2017] [Indexed: 12/13/2022]
Abstract
Cochlear implantation (CI), which directly stimulates the cochlear nerves, is the most effective and widely used medical intervention for patients with severe to profound sensorineural hearing loss. The etiology of the hearing loss is speculated to have a major influence of CI outcomes, particularly in cases resulting from mutations in genes preferentially expressed in the spiral ganglion region. To elucidate precise gene expression levels in each part of the cochlea, we performed laser-capture micro dissection in combination with next-generation sequencing analysis and determined the expression levels of all known deafness-associated genes in the organ of Corti, spiral ganglion, lateral wall, and spiral limbs. The results were generally consistent with previous reports based on immunocytochemistry or in situ hybridization. As a notable result, the genes associated with many kinds of syndromic hearing loss (such as Clpp, Hars2, Hsd17b4, Lars2 for Perrault syndrome, Polr1c and Polr1d for Treacher Collins syndrome, Ndp for Norrie Disease, Kal for Kallmann syndrome, Edn3 and Snai2 for Waardenburg Syndrome, Col4a3 for Alport syndrome, Sema3e for CHARGE syndrome, Col9a1 for Sticker syndrome, Cdh23, Cib2, Clrn1, Pcdh15, Ush1c, Ush2a, Whrn for Usher syndrome and Wfs1 for Wolfram syndrome) showed higher levels of expression in the spiral ganglion than in other parts of the cochlea. This dataset will provide a base for more detailed analysis in order to clarify gene functions in the cochlea as well as predict CI outcomes based on gene expression data.
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Functional Analysis of the Transmembrane and Cytoplasmic Domains of Pcdh15a in Zebrafish Hair Cells. J Neurosci 2017; 37:3231-3245. [PMID: 28219986 DOI: 10.1523/jneurosci.2216-16.2017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 02/07/2017] [Accepted: 02/10/2017] [Indexed: 11/21/2022] Open
Abstract
Protocadherin 15 (PCDH15) is required for mechanotransduction in sensory hair cells as a component of the tip link. Isoforms of PCDH15 differ in their cytoplasmic domains (CD1, CD2, and CD3), but share the extracellular and transmembrane (TMD) domains, as well as an intracellular domain known as the common region (CR). In heterologous expression systems, both the TMD and CR of PCDH15 have been shown to interact with members of the mechanotransduction complex. The in vivo significance of these protein-protein interaction domains of PCDH15 in hair cells has not been determined. Here, we examined the localization and function of the two isoforms of zebrafish Pcdh15a (CD1 and CD3) in pcdh15a-null mutants by assessing Pcdh15a transgene-mediated rescue of auditory/vestibular behavior and hair cell morphology and activity. We found that either isoform alone was able to rescue the Pcdh15a-null phenotype and that the CD1- or CD3-specific regions were dispensable for hair bundle integrity and labeling of hair cells with FM4-64, which was used as a proxy for mechanotransduction. When either the CR or TMD domain was deleted, the mutated proteins localized to the stereocilial tips, but were unable to rescue FM4-64 labeling. Disrupting both domains led to a complete failure of Pcdh15a to localize to the hair bundle. Our findings demonstrate that the TMD and cytoplasmic CR domains are required for the in vivo function of Pcdh15a in zebrafish hair cells.SIGNIFICANCE STATEMENT Tip links transmit force to mechanotransduction channels at the tip of hair bundles in sensory hair cells. One component of tip links is Protocadherin 15 (PCDH15). Here, we demonstrate that, when transgenically expressed, either zebrafish Pcdh15a-cytodomain 1 (CD1) or Pcdh15a-CD3 can rescue the phenotype of a pcdh15a-null mutant. Even when lacking the specific regions for CD1 or CD3, truncated Pcdh15a that contains the so-called common region (CR) at the cytoplasmic/membrane interface still has the ability to rescue similar to full-length Pcdh15a. In contrast, Pcdh15a lacking the entire cytoplasmic domain is not functional. These results demonstrate that the CR plays a key role in the mechanotransduction complex in hair cells.
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Mutations in eight small DFNB genes are not a frequent cause of non-syndromic hereditary hearing loss in Czech patients. Int J Pediatr Otorhinolaryngol 2016; 86:27-33. [PMID: 27260575 DOI: 10.1016/j.ijporl.2016.04.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/03/2016] [Accepted: 04/04/2016] [Indexed: 11/21/2022]
Abstract
OBJECTIVES To evaluate the contribution of eight small NSHL-AR (non-syndromic deafness, autosomal recessive) genes to hereditary hearing loss in Czech patients. PATIENTS AND METHODS Unrelated Czech patients, adults and children, diagnosed with pre-lingual hereditary hearing loss with at least one similarly affected deaf sibling and with previously excluded mutations in the GJB2 gene were investigated by Sanger sequencing of the selected eight small NSHL-AR associated genes (CABP2 - 51 patients, CIB2 - 45 patients, PJVK/DFNB59 - 53 patients, GJB3 - 46 patients, ILDR1 - 48 patients, LHFPL5 - 66 patients, LRTOMT - 60 patients, TMIE - 64 patients). RESULTS Mutations were detected in the LHFPL5 (DFNB67) gene. The patient is heterozygote for two already described pathogenic variants (p.Tyr127Cys, p.Thr165Met). In five samples, five rare heterozygous variants (two novel) predicted as pathogenic were detected in genes CABP2, ILDR1, LHFPL5 and LRTOMT. CONCLUSION Mutations in eight small NSHL-AR genes are not a frequent cause of hereditary hearing loss in the Czech Republic. This diagnostic approach permitted the clarification of HL in only one patient - two heterozygous mutations were detected in LHFPL5 gene for the first time in Central Europe. As the use of panel base MPS certainly improves the diagnostic yield, future studies should rather profit from that diagnostic strategy.
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36
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Imtiaz A, Maqsood A, Rehman AU, Morell RJ, Holt JR, Friedman TB, Naz S. Recessive mutations of TMC1 associated with moderate to severe hearing loss. Neurogenetics 2016; 17:115-123. [PMID: 26879195 PMCID: PMC4795972 DOI: 10.1007/s10048-016-0477-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 02/09/2016] [Indexed: 12/12/2022]
Abstract
TMC1 encodes a protein required for the normal function of mechanically activated channels that enable sensory transduction in auditory and vestibular hair cells. TMC1 protein is localized at the tips of the hair cell stereocilia, the site of conventional mechanotransduction. In many populations, loss-of-function recessive mutations of TMC1 are associated with profound deafness across all frequencies tested. In six families reported here, variable moderate-to-severe or moderate-to-profound hearing loss co-segregated with STR (short tandem repeats) markers at the TMC1 locus DFNB7/11. Massively parallel and Sanger sequencing of genomic DNA revealed each family co-segregating hearing loss with a homozygous TMC1 mutation: two reported mutations (p.R34X and p.R389Q) and three novel mutations (p.S596R, p.N199I, and c.1404 + 1G > T). TMC1 cDNA sequence from affected subjects homozygous for the donor splice site transversion c.1404 + 1G > T revealed skipping of exon 16, deleting 60 amino acids from the TMC1 protein. Since the mutations in our study cause less than profound hearing loss, we speculate that there is hypo-functional TMC1 mechanotransduction channel activity and that other even less damaging variants of TMC1 may be associated with more common mild-to-severe sensorineural hearing loss.
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Affiliation(s)
- Ayesha Imtiaz
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore 54590, Pakistan
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, USA 20892
| | - Azra Maqsood
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore 54590, Pakistan
| | - Atteeq U. Rehman
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, USA 20892
| | - Robert J. Morell
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, USA 20892
| | - Jeffrey R. Holt
- Department of Otolaryngology, F. M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Thomas B. Friedman
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, USA 20892
| | - Sadaf Naz
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore 54590, Pakistan
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37
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Novel function of LHFPL2 in female and male distal reproductive tract development. Sci Rep 2016; 6:23037. [PMID: 26964900 PMCID: PMC4786858 DOI: 10.1038/srep23037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/29/2016] [Indexed: 01/04/2023] Open
Abstract
Congenital reproductive tract anomalies could impair fertility. Female and male reproductive tracts are developed from Müllerian ducts and Wolffian ducts, respectively, involving initiation, elongation and differentiation. Genetic basis solely for distal reproductive tract development is largely unknown. Lhfpl2 (lipoma HMGIC fusion partner-like 2) encodes a tetra-transmembrane protein with unknown functions. It is expressed in follicle cells of ovary and epithelial cells of reproductive tracts. A spontaneous point mutation of Lhfpl2 (LHFPL2G102E) leads to infertility in 100% female mice, which have normal ovarian development, ovulation, uterine development, and uterine response to exogenous estrogen stimulation, but abnormal upper longitudinal vaginal septum and lower vaginal agenesis. Infertility is also observed in ~70% mutant males, which have normal mating behavior and sperm counts, but abnormal distal vas deferens convolution resulting in complete and incomplete blockage of reproductive tract in infertile and fertile males, respectively. On embryonic day 15.5, mutant Müllerian ducts and Wolffian ducts have elongated but their duct tips are enlarged and fail to merge with the urogenital sinus. These findings provide a novel function of LHFPL2 and a novel genetic basis for distal reproductive tract development; they also emphasize the importance of an additional merging phase for proper reproductive tract development.
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Egilmez OK, Kalcioglu MT. Genetics of Nonsyndromic Congenital Hearing Loss. SCIENTIFICA 2016; 2016:7576064. [PMID: 26989561 PMCID: PMC4775805 DOI: 10.1155/2016/7576064] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 01/19/2016] [Indexed: 06/05/2023]
Abstract
Congenital hearing impairment affects nearly 1 in every 1000 live births and is the most frequent birth defect in developed societies. Hereditary types of hearing loss account for more than 50% of all congenital sensorineural hearing loss cases and are caused by genetic mutations. HL can be either nonsyndromic, which is restricted to the inner ear, or syndromic, a part of multiple anomalies affecting the body. Nonsyndromic HL can be categorised by mode of inheritance, such as autosomal dominant (called DFNA), autosomal recessive (DFNB), mitochondrial, and X-linked (DFN). To date, 125 deafness loci have been reported in the literature: 58 DFNA loci, 63 DFNB loci, and 4 X-linked loci. Mutations in genes that control the adhesion of hair cells, intracellular transport, neurotransmitter release, ionic hemeostasis, and cytoskeleton of hair cells can lead to malfunctions of the cochlea and inner ear. In recent years, with the increase in studies about genes involved in congenital hearing loss, genetic counselling and treatment options have emerged and increased in availability. This paper presents an overview of the currently known genes associated with nonsyndromic congenital hearing loss and mutations in the inner ear.
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Affiliation(s)
- Oguz Kadir Egilmez
- Department of Otorhinolaryngology, Faculty of Medicine, Istanbul Medeniyet University, 34722 Istanbul, Turkey
| | - M. Tayyar Kalcioglu
- Department of Otorhinolaryngology, Faculty of Medicine, Istanbul Medeniyet University, 34722 Istanbul, Turkey
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Bianchi M, Dahlgren S, Massey J, Dietschi E, Kierczak M, Lund-Ziener M, Sundberg K, Thoresen SI, Kämpe O, Andersson G, Ollier WER, Hedhammar Å, Leeb T, Lindblad-Toh K, Kennedy LJ, Lingaas F, Rosengren Pielberg G. A Multi-Breed Genome-Wide Association Analysis for Canine Hypothyroidism Identifies a Shared Major Risk Locus on CFA12. PLoS One 2015; 10:e0134720. [PMID: 26261983 PMCID: PMC4532498 DOI: 10.1371/journal.pone.0134720] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 07/13/2015] [Indexed: 01/12/2023] Open
Abstract
Hypothyroidism is a complex clinical condition found in both humans and dogs, thought to be caused by a combination of genetic and environmental factors. In this study we present a multi-breed analysis of predisposing genetic risk factors for hypothyroidism in dogs using three high-risk breeds—the Gordon Setter, Hovawart and the Rhodesian Ridgeback. Using a genome-wide association approach and meta-analysis, we identified a major hypothyroidism risk locus shared by these breeds on chromosome 12 (p = 2.1x10-11). Further characterisation of the candidate region revealed a shared ~167 kb risk haplotype (4,915,018–5,081,823 bp), tagged by two SNPs in almost complete linkage disequilibrium. This breed-shared risk haplotype includes three genes (LHFPL5, SRPK1 and SLC26A8) and does not extend to the dog leukocyte antigen (DLA) class II gene cluster located in the vicinity. These three genes have not been identified as candidate genes for hypothyroid disease previously, but have functions that could potentially contribute to the development of the disease. Our results implicate the potential involvement of novel genes and pathways for the development of canine hypothyroidism, raising new possibilities for screening, breeding programmes and treatments in dogs. This study may also contribute to our understanding of the genetic etiology of human hypothyroid disease, which is one of the most common endocrine disorders in humans.
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Affiliation(s)
- Matteo Bianchi
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Stina Dahlgren
- Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Jonathan Massey
- Centre for Integrated Genomic Medical Research, The University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Elisabeth Dietschi
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Marcin Kierczak
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Martine Lund-Ziener
- Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Katarina Sundberg
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Stein Istre Thoresen
- Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Olle Kämpe
- Department of Medicine (Solna), Karolinska Institutet, Stockholm, Sweden
| | - Göran Andersson
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - William E. R. Ollier
- Centre for Integrated Genomic Medical Research, The University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Åke Hedhammar
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Tosso Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Kerstin Lindblad-Toh
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Lorna J. Kennedy
- Centre for Integrated Genomic Medical Research, The University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Frode Lingaas
- Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Gerli Rosengren Pielberg
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- * E-mail:
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Pan B, Holt JR. The molecules that mediate sensory transduction in the mammalian inner ear. Curr Opin Neurobiol 2015. [PMID: 26218316 DOI: 10.1016/j.conb.2015.06.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Years of searching and researching have finally yielded a few leads in the quest to identify molecules required for mechanosensory transduction in the mammalian inner ear. Studies of human and mouse genetics have raised the profile of several molecules that are crucial for the function sensory hair cells. Follow up studies have begun to define the molecular function and biochemical interactions of several key proteins. These studies have exposed a sensory transduction apparatus that is more complex than originally envisioned and have reinvigorated the search for additional molecular components required for normal inner ear function.
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Affiliation(s)
- Bifeng Pan
- Department of Otolaryngology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, United States
| | - Jeffrey R Holt
- Department of Otolaryngology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, United States.
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Yan D, Kannan-Sundhari A, Vishwanath S, Qing J, Mittal R, Kameswaran M, Liu XZ. The Genetic Basis of Nonsyndromic Hearing Loss in Indian and Pakistani Populations. Genet Test Mol Biomarkers 2015; 19:512-27. [PMID: 26186295 DOI: 10.1089/gtmb.2015.0023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Deafness encompasses a series of etiologically heterogeneous disorders with mutations in more than 400 independent genes. However, several studies indicate that a large proportion of both syndromic and nonsyndromic forms of deafness in the racially diverse Indian and Pakistani populations are caused by defects in just a few genes. In these countries, there is a strong cultural preference for consanguineous marriage and an associated relatively high prevalence of genetic disorders. The current Indian population is approximately 1.2 billion and it is estimated that 30,000 infants are born with congenital sensorineural hearing loss (HL) each year. The estimated rate of profound bilateral HL is 1.6 per 1000 in Pakistan and 70% of this HL arises in consanguineous families. Knowledge of the genetic cause of deafness within a distinct population is important for accurate genetic counseling and early diagnosis for timely intervention and treatment options. Many sources and technologies are now available for the testing of hearing efficiency. Population-based screening has been proposed as one of the major strategies for translating genetic and genomic advances into population health gains. This review of the genetics of deafness in Indian and Pakistani populations deals with the major causes of deafness in these countries and prospectives for reducing the incidence of inherited deafness.
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Affiliation(s)
- Denise Yan
- 1 Departments of Otolaryngology-Head and Neck Surgery, Leonard M. Miller School of Medicine, University of Miami , Miami, Florida
| | - Abhiraami Kannan-Sundhari
- 1 Departments of Otolaryngology-Head and Neck Surgery, Leonard M. Miller School of Medicine, University of Miami , Miami, Florida.,2 SRM University , SRM Nagar, Chennai, India
| | - Subramanian Vishwanath
- 1 Departments of Otolaryngology-Head and Neck Surgery, Leonard M. Miller School of Medicine, University of Miami , Miami, Florida.,2 SRM University , SRM Nagar, Chennai, India
| | - Jie Qing
- 1 Departments of Otolaryngology-Head and Neck Surgery, Leonard M. Miller School of Medicine, University of Miami , Miami, Florida
| | - Rahul Mittal
- 1 Departments of Otolaryngology-Head and Neck Surgery, Leonard M. Miller School of Medicine, University of Miami , Miami, Florida
| | | | - Xue Zhong Liu
- 1 Departments of Otolaryngology-Head and Neck Surgery, Leonard M. Miller School of Medicine, University of Miami , Miami, Florida
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Nishio SY, Hattori M, Moteki H, Tsukada K, Miyagawa M, Naito T, Yoshimura H, Iwasa YI, Mori K, Shima Y, Sakuma N, Usami SI. Gene expression profiles of the cochlea and vestibular endorgans: localization and function of genes causing deafness. Ann Otol Rhinol Laryngol 2015; 124 Suppl 1:6S-48S. [PMID: 25814645 DOI: 10.1177/0003489415575549] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVES We sought to elucidate the gene expression profiles of the causative genes as well as the localization of the encoded proteins involved in hereditary hearing loss. METHODS Relevant articles (as of September 2014) were searched in PubMed databases, and the gene symbols of the genes reported to be associated with deafness were located on the Hereditary Hearing Loss Homepage using localization, expression, and distribution as keywords. RESULTS Our review of the literature allowed us to systematize the gene expression profiles for genetic deafness in the inner ear, clarifying the unique functions and specific expression patterns of these genes in the cochlea and vestibular endorgans. CONCLUSIONS The coordinated actions of various encoded molecules are essential for the normal development and maintenance of auditory and vestibular function.
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Affiliation(s)
- Shin-Ya Nishio
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Japan
| | - Mitsuru Hattori
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Hideaki Moteki
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Keita Tsukada
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Maiko Miyagawa
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Japan
| | - Takehiko Naito
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Hidekane Yoshimura
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Yoh-Ichiro Iwasa
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Kentaro Mori
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Yutaka Shima
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Naoko Sakuma
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan Department of Otorhinolaryngology and Head and Neck Surgery, Yokohama City University School of Medicine, Yokohama, Japan
| | - Shin-Ichi Usami
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Japan
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Abstract
Hearing loss is the most common form of sensory impairment in humans and affects more than 40 million people in the United States alone. No drug-based therapy has been approved by the Food and Drug Administration, and treatment mostly relies on devices such as hearing aids and cochlear implants. Over recent years, more than 100 genetic loci have been linked to hearing loss and many of the affected genes have been identified. This understanding of the genetic pathways that regulate auditory function has revealed new targets for pharmacological treatment of the disease. Moreover, approaches that are based on stem cells and gene therapy, which may have the potential to restore or maintain auditory function, are beginning to emerge.
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Affiliation(s)
- Ulrich Müller
- Department of Molecular and Cellular Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, San Diego, California 92037, USA
| | - Peter G Barr-Gillespie
- Oregon Hearing Research Center, Vollum Institute, Oregon Health &Science University, 3181 South West Sam Jackson Park Road, Portland, Oregon 97239, USA
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Subunit determination of the conductance of hair-cell mechanotransducer channels. Proc Natl Acad Sci U S A 2014; 112:1589-94. [PMID: 25550511 DOI: 10.1073/pnas.1420906112] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Cochlear hair cells convert sound stimuli into electrical signals by gating of mechanically sensitive ion channels in their stereociliary (hair) bundle. The molecular identity of this ion channel is still unclear, but its properties are modulated by accessory proteins. Two such proteins are transmembrane channel-like protein isoform 1 (TMC1) and tetraspan membrane protein of hair cell stereocilia (TMHS, also known as lipoma HMGIC fusion partner-like 5, LHFPL5), both thought to be integral components of the mechanotransduction machinery. Here we show that, in mice harboring an Lhfpl5 null mutation, the unitary conductance of outer hair cell mechanotransducer (MT) channels was reduced relative to wild type, and the tonotopic gradient in conductance, where channels from the cochlear base are nearly twice as conducting as those at the apex, was almost absent. The macroscopic MT current in these mutants was attenuated and the tonotopic gradient in amplitude was also lost, although the current was not completely extinguished. The consequences of Lhfpl5 mutation mirror those due to Tmc1 mutation, suggesting a part of the MT-channel conferring a large and tonotopically variable conductance is similarly disrupted in the absence of Lhfpl5 or Tmc1. Immunolabelling demonstrated TMC1 throughout the stereociliary bundles in wild type but not in Lhfpl5 mutants, implying the channel effect of Lhfpl5 mutations stems from down-regulation of TMC1. Both LHFPL5 and TMC1 were shown to interact with protocadherin-15, a component of the tip link, which applies force to the MT channel. We propose that titration of the TMC1 content of the MT channel sets the gradient in unitary conductance along the cochlea.
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45
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Zhao B, Wu Z, Grillet N, Yan L, Xiong W, Harkins-Perry S, Müller U. TMIE is an essential component of the mechanotransduction machinery of cochlear hair cells. Neuron 2014; 84:954-67. [PMID: 25467981 PMCID: PMC4258123 DOI: 10.1016/j.neuron.2014.10.041] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2014] [Indexed: 12/18/2022]
Abstract
Hair cells are the mechanosensory cells of the inner ear. Mechanotransduction channels in hair cells are gated by tip links. The molecules that connect tip links to transduction channels are not known. Here we show that the transmembrane protein TMIE forms a ternary complex with the tip-link component PCDH15 and its binding partner TMHS/LHFPL5. Alternative splicing of the PCDH15 cytoplasmic domain regulates formation of this ternary complex. Transducer currents are abolished by a homozygous Tmie-null mutation, and subtle Tmie mutations that disrupt interactions between TMIE and tip links affect transduction, suggesting that TMIE is an essential component of the hair cell's mechanotransduction machinery that functionally couples the tip link to the transduction channel. The multisubunit composition of the transduction complex and the regulation of complex assembly by alternative splicing is likely critical for regulating channel properties in different hair cells and along the cochlea's tonotopic axis.
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Affiliation(s)
- Bo Zhao
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Zizhen Wu
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Nicolas Grillet
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Linxuan Yan
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Wei Xiong
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Sarah Harkins-Perry
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Ulrich Müller
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA.
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46
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Li J, Zhao X, Xin Q, Shan S, Jiang B, Jin Y, Yuan H, Dai P, Xiao R, Zhang Q, Xiao J, Shao C, Gong Y, Liu Q. Whole-exome sequencing identifies a variant in TMEM132E causing autosomal-recessive nonsyndromic hearing loss DFNB99. Hum Mutat 2014; 36:98-105. [PMID: 25331638 DOI: 10.1002/humu.22712] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 10/06/2014] [Indexed: 11/06/2022]
Abstract
Autosomal-recessive nonsyndromic hearing loss (ARNSHL) features a high degree of genetic heterogeneity. Many genes responsible for ARNSHL have been identified or mapped. We previously mapped an ARNSHL locus at 17q12, herein designated DFNB99, in a consanguineous Chinese family. In this study, whole-exome sequencing revealed a homozygous missense mutation (c.1259G>A, p.Arg420Gln) in the gene-encoding transmembrane protein 132E (TMEM132E) as the causative variant. Immunofluorescence staining of the Organ of Corti showed Tmem132e highly expressed in murine inner hair cells. Furthermore, knockdown of the tmem132e ortholog in zebrafish affected the mechanotransduction of hair cells. Finally, wild-type human TMEM132E mRNA, but not the mRNA carrying the c.1259G>A mutation rescued the Tmem132e knockdown phenotype. We conclude that the variant in TMEM132E is the most likely cause of DFNB99.
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Affiliation(s)
- Jiangxia Li
- Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Medical Genetics, Shandong University School of Medicine, Jinan, Shandong, 250012, China
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Meyer Zum Gottesberge AM, Hansen S. The collagen receptor DDR1 co-localizes with the non-muscle myosin IIA in mice inner ear and contributes to the cytoarchitecture and stability of motile cells. Cell Tissue Res 2014; 358:729-36. [PMID: 25307162 DOI: 10.1007/s00441-014-2009-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 09/11/2014] [Indexed: 01/13/2023]
Abstract
Discoidin domain receptor 1 (DDR1) is a tyrosine kinase receptor activated by native collagen. DDRs regulate cell adhesion, migration and various other cell functions. Deletion of the DDR1 gene in mice is associated with a severe decrease in auditory function and substantial structural alterations in a heterogeneous group of cells, including cells containing actin/myosin contractile elements, e.g., outer hair cells (OHCs) (Meyer zum Gottesberge et al. Lab Invest, 88: 27-37, 2008). The non-muscle myosin heavy chain isoform IIA (NM-IIA), encoded by MYH9, is implicated in the regulation of cell spreading, cellular reshaping and movement and cell migration and adhesion. In this study, we identify DDR1 and NM-IIA co-localization in the type III fibrocytes (tension fibrocytes) of the spiral ligament, the OHCs and the stereocilia of both OHCs and inner hair cells. We show for the first time that DDR1 malfunction causes OHC deformation and the separation of the lateral wall, the location of the cellular motor responsible for the electromotile property, explicitly in those regions showing DDR1 and NM-IIA co-localization. On the basis of our results, we propose that DDR1 acts in concert with proteins of the actin/myosin complex to maintain mechanical forces in the inner ear and to stabilize OHC cellular shape for proper auditory signal transduction.
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Affiliation(s)
- A M Meyer Zum Gottesberge
- Department of Otorhinolaryngology, Research Laboratory, Medical Faculty, Heinrich-Heine-University Düsseldorf, No. 23.12, Universitätsstr. 1, 40225, Düsseldorf, Germany,
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Effertz T, Scharr AL, Ricci AJ. The how and why of identifying the hair cell mechano-electrical transduction channel. Pflugers Arch 2014; 467:73-84. [PMID: 25241775 DOI: 10.1007/s00424-014-1606-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 08/28/2014] [Accepted: 09/01/2014] [Indexed: 01/10/2023]
Abstract
Identification of the auditory hair cell mechano-electrical transduction (hcMET) channel has been a major focus in the hearing research field since the 1980s when direct mechanical gating of a transduction channel was proposed (Corey and Hudspeth J Neurosci 3:962-976, 1983). To this day, the molecular identity of this channel remains controversial. However, many of the hcMET channel's properties have been characterized, including pore properties, calcium-dependent ion permeability, rectification, and single channel conductance. At this point, elucidating the molecular identity of the hcMET channel will provide new tools for understanding the mechanotransduction process. This review discusses the significance of identifying the hcMET channel, the difficulties associated with that task, as well as the establishment of clear criteria for this identification. Finally, we discuss potential candidate channels in light of these criteria.
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Affiliation(s)
- Thomas Effertz
- Department of Otolaryngology, School of Medicine, Stanford University, Stanford, CA, 94305, USA
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49
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Fettiplace R, Kim KX. The physiology of mechanoelectrical transduction channels in hearing. Physiol Rev 2014; 94:951-86. [PMID: 24987009 DOI: 10.1152/physrev.00038.2013] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Much is known about the mechanotransducer (MT) channels mediating transduction in hair cells of the vertrbrate inner ear. With the use of isolated preparations, it is experimentally feasible to deliver precise mechanical stimuli to individual cells and record the ensuing transducer currents. This approach has shown that small (1-100 nm) deflections of the hair-cell stereociliary bundle are transmitted via interciliary tip links to open MT channels at the tops of the stereocilia. These channels are cation-permeable with a high selectivity for Ca(2+); two channels are thought to be localized at the lower end of the tip link, each with a large single-channel conductance that increases from the low- to high-frequency end of the cochlea. Ca(2+) influx through open channels regulates their resting open probability, which may contribute to setting the hair cell resting potential in vivo. Ca(2+) also controls transducer fast adaptation and force generation by the hair bundle, the two coupled processes increasing in speed from cochlear apex to base. The molecular intricacy of the stereocilary bundle and the transduction apparatus is reflected by the large number of single-gene mutations that are linked to sensorineural deafness, especially those in Usher syndrome. Studies of such mutants have led to the discovery of many of the molecules of the transduction complex, including the tip link and its attachments to the stereociliary core. However, the MT channel protein is still not firmly identified, nor is it known whether the channel is activated by force delivered through accessory proteins or by deformation of the lipid bilayer.
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Affiliation(s)
- Robert Fettiplace
- Department of Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin
| | - Kyunghee X Kim
- Department of Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin
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50
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Abstract
Uniquely among human senses, hearing is not simply a passive response to stimulation. Our auditory system is instead enhanced by an active process in cochlear hair cells that amplifies acoustic signals several hundred-fold, sharpens frequency selectivity and broadens the ear's dynamic range. Active motility of the mechanoreceptive hair bundles underlies the active process in amphibians and some reptiles; in mammals, this mechanism operates in conjunction with prestin-based somatic motility. Both individual hair bundles and the cochlea as a whole operate near a dynamical instability, the Hopf bifurcation, which accounts for the cardinal features of the active process.
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