This study aimed to investigate the transduction efficiency of triple adeno-associated virus (AAV) vectors in the cochleae of adult mice, focusing on large-gene-associated hearing loss (HL). ...Additionally, we sought to evaluate the feasibility of cochlear gene therapy in a mouse model of human
-mediated HL using the triple AAV approach. To create a reporter protein, we fused EGFP to mCherry, which was then divided into three parts, each packaged in a separate AAV2/2 vector. Four weeks after co-injecting the triple AAV vectors into 4-5-week-old mice, we assessed transduction efficiency. We found that up to 5.9% of inner hair cells were positive for both EGFP and mCherry. Subsequently, we developed triple
AAV vectors for therapeutic purposes. After administering these vectors to 4- to 5-week-old C57/BL6 mice, we conducted auditory tests and immunohistochemistry studies over a period of 60 weeks. Co-injecting triple
-AAVs did not alter auditory function or lead to hair cell degeneration. In conclusion, this study confirms the feasibility of the triple-AAV approach for cochlear gene delivery. While this strategy did not produce any treatment effects, our findings suggest that large deafness genes could be potential future targets for cochlear gene therapy.
Single-cell RNA sequencing is a powerful tool by which to characterize the transcriptional profile of low-abundance cell types, but its application to the inner ear has been hampered by the bony ...labyrinth, tissue sparsity, and difficulty dissociating the ultra-rare cells of the membranous cochlea. Herein, we present a method to isolate individual inner hair cells (IHCs), outer hair cells (OHCs), and Deiters’ cells (DCs) from the murine cochlea at any post-natal time point. We harvested more than 200 murine IHCs, OHCs, and DCs from post-natal days 15 (p15) to 228 (p228) and leveraged both short- and long-read single-cell RNA sequencing to profile transcript abundance and structure. Our results provide insights into the expression profiles of these cells and document an unappreciated complexity in isoform variety in deafness-associated genes. This refined view of transcription in the organ of Corti improves our understanding of the biology of hearing and deafness.
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•Single-cell RNA-seq identifies inner and outer hair cell defining genes by AUC-ROC•Sorcin, a key component for cardiac excitation-contraction, is a top marker of OHCs•Analysis of deafness-associated genes identifies heretofore unrecognized exons•Nanopore long-read RNA-seq reveals splicing diversity and isoform abundance
Single-cell RNA-seq of inner and outer auditory hair cells facilitates the identification of cell type-defining genes across a range of expression levels. Full-length reverse transcription with long-read sequencing identifies novel exons and unappreciated splicing diversity among deafness-associated genes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We present detailed comparative analyses to assess population-level differences in patterns of genetic deafness between European/American and Japanese cohorts with non-syndromic hearing loss. One ...thousand eighty-three audiometric test results (921 European/American and 162 Japanese) from members of 168 families (48 European/American and 120 Japanese) with non-syndromic hearing loss secondary to pathogenic variants in one of three genes (
KCNQ4
,
TECTA
,
WFS1
) were studied. Audioprofile characteristics, specific mutation types, and protein domains were considered in the comparative analyses. Our findings support differences in audioprofiles driven by both mutation type (non-truncating vs. truncating) and ethnic background. The former finding confirms data that ascribe a phenotypic consequence to different mutation types in
KCNQ4
; the latter finding suggests that there are ethnic-specific effects (genetic and/or environmental) that impact gene-specific audioprofiles for
TECTA
and
WFS1
. Identifying the drivers of ethnic differences will refine our understanding of phenotype–genotype relationships and the biology of hearing and deafness.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The present study was conducted to define the relationship between the anti-aging effect of ubiquinol-10 supplementation and mitochondrial activation in senescence-accelerated mouse prone 1 (SAMP1) ...mice.
Here, we report that dietary supplementation with ubiquinol-10 prevents age-related decreases in the expression of sirtuin gene family members, which results in the activation of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a major factor that controls mitochondrial biogenesis and respiration, as well as superoxide dismutase 2 (SOD2) and isocitrate dehydrogenase 2 (IDH2), which are major mitochondrial antioxidant enzymes. Ubiquinol-10 supplementation can also increase mitochondrial complex I activity and decrease levels of oxidative stress markers, including protein carbonyls, apurinic/apyrimidinic sites, malondialdehydes, and increase the reduced glutathione/oxidized glutathione ratio. Furthermore, ubiquinol-10 may activate Sirt1 and PGC-1α by increasing cyclic adenosine monophosphate (cAMP) levels that, in turn, activate cAMP response element-binding protein (CREB) and AMP-activated protein kinase (AMPK).
These results show that ubiquinol-10 may enhance mitochondrial activity by increasing levels of SIRT1, PGC-1α, and SIRT3 that slow the rate of age-related hearing loss and protect against the progression of aging and symptoms of age-related diseases.
Background: Recent advances in less-invasive surgery and electrode design allow for a high degree of hearing preservation (HP) after cochlear implantation (CI), although residual hearing still ...deteriorates in some patients. To date, the factors predictive of preserving residual hearing remain a controversial topic.
Objective: The aim of this study was to investigate the predictive factors, including the etiology of hearing loss (HL) as a patient-related factor, influencing residual HP after CI.
Methods: Forty-four patients (50 ears, 41 families) with residual acoustic hearing who underwent CI were included. Auditory thresholds before and at 6 months after initial activation were measured. Genetic testing was performed to identify the responsible genes for HL.
Results: We identified the cause of HL in 21 families (51.2%). HP was marginally correlated with age at implantation, while it was independent of pre-operative low-frequency hearing thresholds, cochlear duct length, and electrode length. We found that patients who had pathogenic variants in the CDH23, MYO7A, or MYO15A gene showed statistically better HP scores compared with patients with HL due to other causes (p = .002).
Conclusions: Identification of the etiology of HL using genetic testing is likely to facilitate the prediction of HP after implant surgery.
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DOBA, IJS, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Key Clinical Message
Hematohidrosis is a rare disorder characterized by bloody sweating on the skin without trauma. The ear, nose, and other facial areas are the most commonly affected sites. This ...study shows usefulness of beta‐blockers in the treatment of hematohidrosis.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Congenital cytomegalovirus-associated hearing loss (cCMV-associated HL) is a common cause of congenital or early-onset deafness. Although cCMV infection has been reported to lead to various types of ...HL, the natural course of cCMV-associated HL over a long period is not yet known.
To investigate the clinical phenotype of cCMV-associated HL in the largest study to date.
Thirty-one CMV-positive children, diagnosed by examining CMV DNA extracted from their dried umbilical cords retrospectively, were divided into unilateral and bilateral HL groups, and their hearing ability was evaluated using pure-tone audiometry and auditory steady-state response over time.
Thirteen patients (41.9%) had unilateral HL and 18 (58.1%) had bilateral HL. In most cases of unilateral cCMV-associated HL, the ear with better hearing maintained a normal hearing threshold. Notably, in most cases of both unilateral and bilateral HL, the ear with worse hearing ultimately showed severe to profound HL.
Our findings revealed that the natural course of cCMV-associated HL was different between the cases of unilateral and bilateral HL, as well as between the ears with better or worse hearing in all cases. These findings indicate that accurate diagnosis could enable proper follow-up and management of cCMV-associated HL in children.
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DOBA, IJS, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Gene therapy for genetic deafness is a promising approach by which to prevent hearing loss or to restore hearing after loss has occurred. Although a variety of direct approaches to introduce viral ...particles into the inner ear have been described, presumed physiological barriers have heretofore precluded investigation of systemic gene delivery to the cochlea. In this study, we sought to characterize systemic delivery of a rAAV2/9 vector as a non-invasive means of cochlear transduction. In wild-type neonatal mice (postnatal day 0-1), we show that intravenous injection of rAAV2/9 carrying an eGFP-reporter gene results in binaural transduction of inner hair cells, spiral ganglion neurons and vestibular hair cells. Transduction efficiency increases in a dose-dependent manner. Inner hair cells are transduced in an apex-to-base gradient, with transduction reaching 96% in the apical turn. Hearing acuity in treated animals is unaltered at postnatal day 30. Transduction is influenced by viral serotype and age at injection, with less efficient cochlear transduction observed with systemic delivery of rAAV2/1 and in juvenile mice with rAAV2/9. Collectively, these data validate intravenous delivery of rAAV2/9 as a novel and atraumatic technique for inner ear transgene delivery in early postnatal mice.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The purpose of this study was to assess the diagnostic performance of 3T MRI after intratympanic injection of gadodiamide for delayed endolymphatic hydrops (DEH), and assess the relationship between ...endolymphatic hydrops (ELH) and vestibular function in patients diagnosed with DEH and confirmed by 3T MRI. Nineteen patients clinically diagnosed with DEH (11 ipsilateral DEH, 8 contralateral DEH) participated in this study. Diluted gadodiamide was administered to the bilateral tympanic cavity by injection through the tympanic membrane. At 24 hours post-injection, the ELH was evaluated by MRI. Patient vestibular functions were evaluated by caloric testing and cVEMP. ELH was observed in all patients (19/19: positive rate 100%). The distribution patterns of ELH varied between the cochlear or vestibular region. Vestibular ELH was observed in the affected ear in all ipsilateral DEH patients. In the contralateral DEH patients, however, there were individual differences in the distribution patterns of ELH. Six patients (1 ipsilateral DEH, 5 contralateral DEH) had bilateral ELH. No obvious relationships were observed between ELH and vestibular function. ELH distribution was complicated, particularly in the contralateral DEH cases. It was difficult to identify the existence of ELH by vestibular functional testing alone; therefore, 3T MRI is thought to be useful for identifying the affected ear. A significant number of cases had "bilateral" DEH, particularly among the contralateral DEH cases, indicating that we should pay careful attention to this pathology when treating DEH.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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