Generation of four induced pluripotent stem cell lines (KEIUi004-A, KEIUi005-A, KEIUi006-A, and KEIUi007-A) from patients with sensorineural hearing loss with mutation in EYA4 gene.

Disease-related cells differentiated from patient-derived iPSCs are useful for elucidating the pathophysiological mechanisms underlying these diseases. In this study, four iPSC lines were established from independent patients with sensorineural hearing loss and a mutation in EYA4. These iPSCs showed pluripotency, the capacity to differentiate into three germ layers, and normal karyotypes, suggesting that these lines are useful for the pathological study of sensorineural hearing loss and drug screening for ear disorders.

Unbalanced bidirectional radial stiffness gradients within the organ of Corti promoted by TRIOBP.

Hearing depends on intricate morphologies and mechanical properties of diverse inner ear cell types. The individual contributions of various inner ear cell types into mechanical properties of the organ of Corti and the mechanisms of their integration are yet largely unknown. Using sub-100-nm spatial resolution atomic force microscopy (AFM), we mapped the Young's modulus (stiffness) of the apical surface of the different cells of the freshly dissected P5-P6 cochlear epithelium from wild-type and mice lacking either Trio and F-actin binding protein (TRIOBP) isoforms 4 and 5 or isoform 5 only.

Virus-infection in cochlear supporting cells induces audiosensory receptor hair cell death by TRAIL-induced necroptosis.

Although sensorineural hearing loss (SHL) is relatively common, its cause has not been identified in most cases. Previous studies have suggested that viral infection is a major cause of SHL, especially sudden SHL, but the system that protects against pathogens in the inner ear, which is isolated by the blood-labyrinthine barrier, remains poorly understood. We recently showed that, as audiosensory receptor cells, cochlear hair cells (HCs) are protected by surrounding accessory supporting cells (SCs) and greater epithelial ridge (GER or Kölliker's organ) cells (GERCs) against viral infections.

Prevalence and Clinical Characteristics of Hearing Loss Caused by Variants.

Variants in are reported to cause autosomal dominant nonsyndromic hereditary hearing loss (ADNSHL), with 34 variants reported to cause hearing loss in various ethnic groups. However, the available information on prevalence, as well as with regard to clinical features, remains fragmentary. In this study, genetic screening for variants was carried out using a large series of Japanese hearing-loss patients to reveal more detailed information.

Human deafness-associated variants alter the dynamics of key molecules in hair cell stereocilia F-actin cores.

Stereocilia protrude up to 100 µm from the apical surface of vertebrate inner ear hair cells and are packed with cross-linked filamentous actin (F-actin). They function as mechanical switches to convert sound vibration into electrochemical neuronal signals transmitted to the brain. Several genes encode molecular components of stereocilia including actin monomers, actin regulatory and bundling proteins, motor proteins and the proteins of the mechanotransduction complex.

The use of a MITO-Porter to deliver exogenous therapeutic RNA to a mitochondrial disease's cell with a A1555G mutation in the mitochondrial 12S rRNA gene results in an increase in mitochondrial respiratory activity.

We report on validating a mitochondrial gene therapeutic strategy using fibroblasts derived from patients with an A1555G point mutation in mitochondrial DNA coding 12S ribosomal RNA (rRNA (12S)). Wild-type rRNA (12S) as a therapeutic RNA was encapsulated in a mitochondrial targeting liposome, a MITO-Porter (rRNA-MITO-Porter), and an attempt was made to deliver the MITO-Porter to mitochondria of the diseased cells. It was confirmed that the rRNA-MITO-Porter treatment significantly decreased the ratio of the mutant rRNA content.

Novel ACTG1 mutations in patients identified by massively parallel DNA sequencing cause progressive hearing loss.

Human ACTG1 mutations are associated with high-frequency hearing loss, and patients with mutations in this gene are good candidates for electric acoustic stimulation. To better understand the genetic etiology of hearing loss cases, massively parallel DNA sequencing was performed on 7,048 unrelated Japanese hearing loss probands. Among 1,336 autosomal dominant hearing loss patients, we identified 15 probands (1.

Cochlear supporting cells function as macrophage-like cells and protect audiosensory receptor hair cells from pathogens.

To protect the audiosensory organ from tissue damage from the immune system, the inner ear is separated from the circulating immune system by the blood-labyrinth barrier, which was previously considered an immune-privileged site. Recent studies have shown that macrophages are distributed in the cochlea, especially in the spiral ligament, spiral ganglion, and stria vascularis; however, the direct pathogen defence mechanism used by audiosensory receptor hair cells (HCs) has remained obscure. Here, we show that HCs are protected from pathogens by surrounding accessory supporting cells (SCs) and greater epithelial ridge (GER or Kölliker's organ) cells (GERCs).

Clinical Characteristics and In Vitro Analysis of Variants Causing Late-Onset Progressive Hearing Loss.

is known as a genetic cause of autosomal dominant and autosomal recessive inherited hearing loss. In this study, to clarify the frequency and clinical characteristics of hearing loss caused by gene mutations, a large-scale genetic analysis of Japanese patients with hearing loss was performed. By means of massively parallel DNA sequencing (MPS) using next-generation sequencing for 8074 Japanese families, we found 27 variants in 33 families, 22 of which are novel.

POLD1 variants leading to reduced polymerase activity can cause hearing loss without syndromic features.

DNA polymerase δ, whose catalytic subunit is encoded by POLD1, is responsible for synthesizing the lagging strand of DNA. Single heterozygous POLD1 mutations in domains with polymerase and exonuclease activities have been reported to cause syndromic deafness as a part of multisystem metabolic disorder or predisposition to cancer. However, the phenotypes of diverse combinations of POLD1 genotypes have not been elucidated in humans.

Mid-Frequency Hearing Loss Is Characteristic Clinical Feature of -Associated Hearing Loss.

The gene (Locus: DFNB22) is reported to be one of the causative genes for non-syndromic autosomal recessive hearing loss. The copy number variations (CNVs) identified in this gene are also known to cause hearing loss, but have not been identified in Japanese patients with hearing loss. Furthermore, the clinical features of -associated hearing loss have not yet been clarified.

Detailed Clinical Features of Deafness Caused by a Claudin-14 Variant.

Tight junctions are cellular junctions that play a major role in the epithelial barrier function. In the inner ear, claudins, occludin, tricellulin, and angulins form the bicellular or tricellular binding of membrane proteins. In these, one type of claudin gene, , was reported to be responsible for human hereditary hearing loss, DFNB29.

Differential disruption of autoinhibition and defect in assembly of cytoskeleton during cell division decide the fate of human -related cytoskeletopathy.

Background: Diaphanous-related formin 1 (DIA1), which assembles the unbranched actin microfilament and microtubule cytoskeleton, is encoded by . Constitutive activation by the disruption of autoinhibitory interactions between the N-terminal diaphanous inhibitory domain (DID) and C-terminal diaphanous autoregulatory domain (DAD) dysregulates DIA1, resulting in both hearing loss and blood cell abnormalities.

Methods And Results: Here, we report the first constitutively active mutant in the DID (p.

TRIOBP-5 sculpts stereocilia rootlets and stiffens supporting cells enabling hearing.

TRIOBP remodels the cytoskeleton by forming unusually dense F-actin bundles and is implicated in human cancer, schizophrenia, and deafness. Mutations ablating human and mouse TRIOBP-4 and TRIOBP-5 isoforms are associated with profound deafness, as inner ear mechanosensory hair cells degenerate after stereocilia rootlets fail to develop. However, the mechanisms regulating formation of stereocilia rootlets by each TRIOBP isoform remain unknown.

A novel splice site mutation of myosin VI in mice leads to stereociliary fusion caused by disruption of actin networks in the apical region of inner ear hair cells.

An unconventional myosin encoded by the myosin VI gene (MYO6) contributes to hearing loss in humans. Homozygous mutations of MYO6 result in nonsyndromic profound congenital hearing loss, DFNB37. Kumamoto shaker/waltzer (ksv) mice harbor spontaneous mutations, and homozygous mutants exhibit congenital defects in balance and hearing caused by fusion of the stereocilia.

Microarray analyses of otospheres derived from the cochlea in the inner ear identify putative transcription factors that regulate the characteristics of otospheres.

Various tissues possess tissue-specific stem/progenitor cells, including the inner ears. Stem/progenitor cells of the inner ear can be isolated as so-called otospheres from differentiated cells using a sphere forming assay. Although recent studies have demonstrated the characteristics of otospheres to some extent, most of the features of these cells are unknown.

Constitutive activation of DIA1 (DIAPH1) via C-terminal truncation causes human sensorineural hearing loss.

DIAPH1 encodes human DIA1, a formin protein that elongates unbranched actin. The c.3634+1G>T DIAPH1 mutation causes autosomal dominant nonsyndromic sensorineural hearing loss, DFNA1, characterized by progressive deafness starting in childhood.

Tricellular Tight Junctions in the Inner Ear.

Tight junctions (TJs) are structures that seal the space between the epithelial cell sheets. In the inner ear, the barrier function of TJs is indispensable for the separation of the endolymphatic and perilymphatic spaces, which is essential for the generation and maintenance of the endocochlear potential (EP). TJs are formed by the intercellular binding of membrane proteins, known as claudins, and mutations in these proteins cause deafness in humans and mice.

Carrier frequency of the GJB2 mutations that cause hereditary hearing loss in the Japanese population.

Hearing impairment is one of the most common sensory disorders that affect ~1 in 1000 children, and half of them are considered to be hereditary. Information about the carrier frequencies of mutations that underlie autosomal recessive disorders is indispensable for accurate genetic counseling to predict the probability of patients' children's disease. However, there have been few reports specific to the Japanese population.

Limited hair cell induction from human induced pluripotent stem cells using a simple stepwise method.

Disease-specific induced pluripotent stem cells (iPS) cells are expected to contribute to exploring useful tools for studying the pathophysiology of inner ear diseases and to drug discovery for treating inner ear diseases. For this purpose, stable induction methods for the differentiation of human iPS cells into inner ear hair cells are required. In the present study, we examined the efficacy of a simple induction method for inducing the differentiation of human iPS cells into hair cells.

Deficiency of angulin-2/ILDR1, a tricellular tight junction-associated membrane protein, causes deafness with cochlear hair cell degeneration in mice.

Tricellular tight junctions seal the extracellular spaces of tricellular contacts, where the vertices of three epithelial cells meet, and are required for the establishment of a strong barrier function of the epithelial cellular sheet. Angulins and tricellulin are known as specific protein components of tricellular tight junctions, where angulins recruit tricellulin. Mutations in the genes encoding angulin-2/ILDR1 and tricellulin have been reported to cause human hereditary deafness DFNB42 and DFNB49, respectively.

Mutational spectrum and clinical features of patients with ACTG1 mutations identified by massively parallel DNA sequencing.

Objectives: ACTG1 has been reported to be a causative gene for autosomal dominant sensorineural hearing loss, DFNA20/26. In this study we sought to clarify the detailed mutational spectrum, clinical features, and genotype-phenotype correlations.

Methods: Massively parallel DNA sequencing (MPS) of 63 target candidate genes was used to screen 1120 Japanese hearing loss patients.

Detailed hearing and vestibular profiles in the patients with COCH mutations.

Objectives: To evaluate the clinical features of Japanese DFNA9 families with mutations of the COCH gene.

Methods: Mutation screening was performed using targeted next-generation sequencing (NGS) for 63 previously reported deafness genes. The progression of hearing loss and vestibular dysfunction were evaluated by pure-tone audiometry, caloric testing, cVEMP, and computed dynamic posturography.

Downsloping high-frequency hearing loss due to inner ear tricellular tight junction disruption by a novel ILDR1 mutation in the Ig-like domain.

The immunoglobulin (Ig)-like domain containing receptor 1 (ILDR1) gene encodes angulin-2/ILDR1, a recently discovered tight junction protein, which forms tricellular tight junction (tTJ) structures with tricellulin and lipolysis-stimulated lipoprotein receptor (LSR) at tricellular contacts (TCs) in the inner ear. Previously reported recessive mutations within ILDR1 have been shown to cause severe to profound nonsyndromic sensorineural hearing loss (SNHL), DFNB42. Whole-exome sequencing of a Korean multiplex family segregating partial deafness identified a novel homozygous ILDR1 variant (p.