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Follicular neoplasms of the thyroid include follicular thyroid carcinoma (FTC) and follicular thyroid adenoma (FTA). However, the differences in cytological findings between FTC and FTA remain undetermined. Here, we aimed to evaluate the accumulation of lipid droplets (LDs) and the expression of adipophilin (perilipin 2/ADRP/ADFP), a known LD marker, in cultured FTC cells. We also immunohistochemically compared adipophilin expression in the FTC and FTA of resected human thyroid tissues. Cultured FTC (FTC-133 and RO82W-1) possessed increased populations of LDs compared to thyroid follicular epithelial (Nthy-ori 3-1) cells. In vitro treatment with phosphatidylinositol-3-kinase (PI3K)/Akt/ mammalian target of rapamycin (mTOR) signaling inhibitors (LY294002, MK2206, and rapamycin) in FTC-133 cells downregulated the PI3K/Akt/mTOR/sterol regulatory element-binding protein 1 (SREBP1) signaling pathway, resulting in a significant reduction in LD accumulation. SREBP1 is a master transcription factor that controls lipid metabolism. Fluorescence immunocytochemistry revealed adipophilin expression in the LDs of FTC-133 cells. Immunohistochemical analysis of surgically resected human thyroid tissues revealed significantly increased expression of adipophilin in FTC compared with FTA and adjacent non-tumorous thyroid epithelia. Taken together, LDs and adipophilin were abundant in cultured FTC; the evaluation of adipophilin expression can help distinguish FTC from FTA in surgical specimens. (c) 2022 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Vocal fold (VF) scar and sulcus cause severe vocal problems, but optimal methods have not been established. Total replacement of the mucosa is required particularly for cases in which the whole lamina propria is occupied by severe fibrosis and vibratory function is totally lost. The amniotic membrane (AM) has been proven to have regenerative potential, as it contains stem cells and growth factors. The current study investigated the biocompatibility and effects of AM for regeneration of the VF mucosa.In vitro and in vivo studies.Vocal fold fibroblasts (VFFs) from 13 Sprague-Dawley rats were seeded on AM and subjected to histology and immunohistochemistry, and gene expressions in the VFFs on AM were examined in in vitro study. Twelve New Zealand White rabbits were used in in vivo study. VFs were stripped down and were reconstructed with AM. The regenerative effects were examined 3 months later by histological examination.In vitro study indicated VFFs survived on AM and stained positively for Ki67, vimentin, and fibronectin. Gene expressions of Has1, Has2, and Hgf were significantly increased in the VFFs on AM compared with the other groups. The in vivo study indicated AM-transplanted VFs showed a significantly higher density of hyaluronic acid and lower density of collagen compared with sham VFs.The current preliminary study suggests biocompatibility and possible regenerative effects of AM for VFs.NA Laryngoscope, 132:2017-2025, 2022.

Effective treatments for vocal fold fibrosis remain elusive. Tamoxifen (TAM) is a selective estrogen receptor modulator and was recently reported to have antifibrotic actions. We hypothesized that TAM inhibits vocal fold fibrosis via altered transforming growth factor beta 1 (TGF-β1) signaling. Both in vitro and in vivo approaches were employed to address this hypothesis.In vitro, vocal fold fibroblasts were treated with TAM (10TAM (10TAM has antifibrotic potential via the regulation of TGF-β1/Smad signaling in vocal fold injury. These findings provide foundational data to develop innovative therapeutic options for vocal fold fibrosis.NA Laryngoscope, 2022.

PURPOSE This study aimed to compare patients with early oral cavity squamous cell carcinoma (OCSCC) (tumor category [T] 1-2, node-negative, and no distant metastasis) treated with traditional elective neck dissection (ND) with those managed by sentinel lymph node biopsy (SLNB) using survival and neck function and complications as end points. METHODS Sixteen institutions in Japan participated in the study (trial registration number: UMIN000006510). Patients of age ≥ 18 years with histologically confirmed, previously untreated OCSCC (Union for International Cancer Control TNM Classification of Malignant Tumors 7th edition T1-2, node-negative no distant metastasis), with ≥ 4 mm (T1) depth of invasion, were randomly assigned to undergo standard selective ND (ND group; n = 137) or SLNB-navigated ND (SLNB group; n = 134). The primary end point was the 3-year overall survival rate, with a 12% noninferiority margin; secondary end points included postoperative neck functionality and complications and 3-year disease-free survival. Sentinel lymph nodes underwent intraoperative multislice frozen section analyses for the diagnosis. Patients with positive sentinel lymph nodes underwent either one-stage or second-look ND. RESULTS Pathologic metastasis-positive nodes were observed in 24.8% (34 of 137) and 33.6% (46 of 134) of patients in the ND and SLNB groups, respectively ( P = .190). The 3-year overall survival in the SLNB group (87.9%; lower limit of one-sided 95% CI, 82.4) was noninferior to that in the ND group (86.6%; lower limit 95% CI, 80.9; P for noninferiority < .001). The 3-year disease-free survival rate was 78.7% (lower limit 95% CI, 72.1) and 81.3% (75.0) in the SLNB and ND groups, respectively ( P for noninferiority < .001). The scores of neck functionality in the SLNB group were significantly better than those in the ND group. CONCLUSION SLNB-navigated ND may replace elective ND without a survival disadvantage and reduce postoperative neck disability in patients with early-stage OCSCC.

Objective: Involvement in the tracheostomy procedure for COVID-19 patients can lead to a feeling of fear in medical staff. To address concerns over infection, we gathered and analyzed experiences with tracheostomy in the COVID-19 patient population from all over Japan. Methods: The data for health-care workers involved in tracheostomies for COVID-19-infected patients were gathered from academic medical centers or their affiliated hospitals from all over Japan. Results: Tracheostomies have been performed in 35 COVID-19 patients with a total of 91 surgeons, 49 anesthesiologists, and 49 surgical staff members involved. Twenty-eight (80%) patients underwent surgery more than 22 days after the development of COVID-19-related symptoms (11: 22-28 days and 17: >= 29 days). Thirty (85.7%) patients underwent surgery >= 15 days after intubation (14: 15-21 days, 6: 22-28 days, and 10: >= 29 days). Among the total of 189 health-care workers involved in the tracheostomy procedures, 25 used a powered air-purifying respirator (PAPR) and 164 used a N95 mask and eye protection. As a result, no transmission to staff occurred during the 2 weeks of follow-up after surgery. Conclusion: No one involved in tracheostomy procedures were found to have been infected with COVID-19 in this Japanese study. The reason is thought to be that the timing of the surgery was quite late after the infections, and the surgery was performed using appropriate PPE and surgical procedure. The indications for and timing of tracheostomy for severe COVID-19 patients should be decided through multidisciplinary discussion. (c) 2021 Oto-Rhino-Laryngological Society of Japan Inc. Published by Elsevier B.V. All rights reserved.

To examine the role of neurons of the pontine respiratory group (PRG) overlapping with the Kölliker-Fuse nucleus in the regulation of swallowing, we compared the activity of swallowing motor activities and interneuron discharge in the dorsal swallowing group in the medulla before and after pharmacological inhibition of the PRG.In 23 in situ perfused brainstem preparation of rats, we recorded the activities of the vagus (VNA), hypoglossal (HNA), and phrenic nerves (PNA), and swallowing interneurons of the dorsal medulla during fictive swallowing elicited by electrical stimulation of the superior laryngeal nerve or oral water injection. Subsequently, respiratory- and swallow-related motor activities and single unit cell discharge were assessed before and after local microinjection of the GABA-receptor agonist muscimol into the area of PRG ipsilateral to the recording sites of swallowing interneurons.After muscimol injection, the amplitude and duration of swallow-related VNA bursts decreased to 71.3 ± 2.84 and 68.1 ± 2.76 % during electrically induced swallowing and VNA interburst intervals during repetitive swallowing decreased. Similar effects were observed for swallowing-related HNA. The swallowing motor activity was similarly qualitatively altered during physiologically induced swallowing. All 23 neurons were changed in either discharge duration or frequency after PRG inhibition, however, the general discharge patterns in relation to the motor output remained unchanged.Descending synaptic inputs from PRG provide control of the primary laryngeal sensory gate and synaptic activity of the PRG partially determine medullary cell and cranial motor nerve activities that govern the pharyngeal stage of swallowing.

Reactive oxygen species (ROS) produced by NADPH oxidases (Nox) contribute to the development of different types of sensorineural hearing loss (SNHL), a common impairment in humans with no established treatment. Although the essential role of Nox3 in otoconia biosynthesis and its possible involvement in hearing have been reported in rodents, immunohistological methods targeted at detecting Nox3 expression in inner ear cells reveal ambiguous results. Therefore, the mechanism underlying Nox3-dependent SNHL remains unclear and warrants further investigation. We generatedNox3-Creknock-in mice, in which Nox3 was replaced withCre recombinase(Cre). UsingNox3-Cre;tdTomatomice of either sex, in which tdTomato is expressed under the control of theNox3promoter, we determined Nox3-expressing regions and cell types in the inner ear. Nox3-expressing cells in the cochlea included various types of supporting cells, outer hair cells, inner hair cells, and spiral ganglion neurons. Nox3 expression increased with cisplatin, age, and noise insults. Moreover, increased Nox3 expression in supporting cells and outer hair cells, especially at the basal turn of the cochlea, played essential roles in ROS-related SNHL. The extent of Nox3 involvement in SNHL follows the following order: cisplatin-induced hearing loss > age-related hearing loss > noise-induced hearing loss. Here, on the basis ofNox3-Cre;tdTomato, which can be used as a reporter system (Nox3-Cre+/−;tdTomato+/+andNox3-Cre+/+;tdTomato+/+), andNox3-KO (Nox3-Cre+/+;tdTomato+/+) mice, we demonstrate that Nox3 inhibition in the cochlea is a promising strategy for ROS-related SNHL, such as cisplatin-induced HL, age-related HL, and noise-induced HL.SIGNIFICANCE STATEMENTWe found Nox3-expressing regions and cell types in the inner ear, especially in the cochlea, usingNox3-Cre;tdTomatomice, a reporter system generated in this study. Nox3 expression increased with cisplatin, age, and noise insults in specific cell types in the cochlea and resulted in the loss (apoptosis) of outer hair cells. Thus, Nox3 might serve as a molecular target for the development of therapeutics for sensorineural hearing loss, particularly cisplatin-induced, age-related, and noise-induced hearing loss.

When animals are infected with helminthic parasites, resistant hosts mount type II helper T (Th2) immune responses to expel worms. Recent studies have clearly shown that epithelial cell-derived cytokines contribute to the induction of Th2 immune responses. Here we demonstrate the role of endogenous thymic stromal lymphopoietin (TSLP) for protection against Strongyloides venezuelensis (S. venezuelensis) infection, utilizing TSLP receptor-deficient Crlf2−/− mice. The number of eggs per gram of feces (EPG) and worm burden were significantly higher in Crlf2−/− mice than in wild type (WT) mice. S. venezuelensis infection induced Tslp mRNA expression in the skin, lung, and intestine and also facilitated the accumulation of mast cells in the intestine in a TSLP-dependent manner. Furthermore, CD4+ T cells from S. venezuelensis-infected Crlf2−/− mice showed diminished capacity to produce Th2 cytokines in the early stage of infection. Finally, CD4+ cell-depleted Crlf2−/− mice still showed higher EPG counts and worm burden than CD4+ cell-depleted WT mice, indicating that TSLP contributes to protecting mice against S. venezuelensis infection in both CD4+ T cell-dependent and -independent manners.

Understanding longitudinal changes of tumor-immune microenvironment during chemo/targeted therapies contributes to the development of optimized combinations of immunotherapy with chemotherapy and targeted therapy for patients with head and neck squamous cell carcinoma (HNSCC). We previously reported a chromogenic sequential immunohistochemical (IHC) platform enabling quantitative and spatial assessment of 29+ biomarkers in a single tissue section (Tsujikawa T et al. Cell Reports 2017, Banik G et al. Methods Enzymology 2020). Using this platform, densities, phenotypes, and distributions of tumor and immune cells were evaluated, comparing baseline and post-treatment specimens from the same individual treated by paclitaxel, carboplatin, and cetuximab (PCE) for advanced HNSCC (N = 30). Immune cell density analyses based on CD8+ T cells, helper T cells, regulatory T cells, B cells, natural killer cells, macrophages, dendritic cells, mast cells, granulocytes revealed the presence of differential immune cell compositions, where immune profiles were divided into hypo-, lymphoid-, and myeloid-inflamed groups according to the same criteria as in our previous report (Tsujikawa et al. Cell Reports 2017). Lymphoid and hypo-inflamed groups exhibited significant tumor volume reduction, increased CD45+ immune cell densities and elevated combined positive scores of PD-L1 at the post-treatment status, suggesting the potential involvement of immunogenic mechanisms related to therapeutic response. On the other hand, the myeloid group exhibited no significant tumor volume reduction, together with higher expression of HIF1α and ZEB2 on tumor cells which are potentially associated with hypoxia and epithelial-mesenchymal transition. In conclusion, longitudinal tissue-based monitoring revealed the presence of differential tumor-immune complexity profiles related to therapeutic efficacy and resistance. Hypo-inflamed profiles might require upfront chemo/targeted therapy before immunotherapy, and myeloid-inflamed profiles might require myeloid cell-targeted therapies, mandating the establishment of rapid clinical assessment of tumor-immune microenvironment. Citation Format: Alisa Kimura, Takahiro Tsujikawa, Junichi Mitsuda, Aya Miyagawa-Hayashino, Hiroki Morimoto, Sumiyo Saburi, Kanako Yoshimura, Gaku Ohmura, Sigeyuki Mukudai, Hikaru Nagao, Yoichiro Sugiyama, Hiroshi Ogi, Saya Shibata, Eiichi Konishi, Kyoko Itoh, Shigeru Hirano. Tumor-immune microenvironmental profiling during chemo- and targeted therapy for head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5172.

Neutrophil-to-lymphocyte ratio (NLR) in peripheral blood is an emerging biomarker candidate of immunotherapy in a wide range of cancers. However, little is known about the potential relationships between the tumor immune microenvironment and systemic inflammatory markers including NLR. Here we have explored systemic and tumor-immune microenvironmental characteristics related to treatment outcomes of immune checkpoint inhibition, based on 29 consecutive patients with recurrent/metastatic head and neck squamous cell carcinoma who received pembrolizumab between 2020 and 2021. NLR greater than 4.5 at pretreatment status significantly correlated with short overall survival (OS). Although NLR did not show a significant association with tumor volumes, high NLR exhibited significant correlations with malnutrition status characterized by CONUT (controlling nutritional status), and GNRI (geriatric nutrition risk index). Among the patients whose NLR was greater than 4.5 at pretreatment status, those whose NLR decreased to less than 4.5 at day 21 had a better OS than those whose NLR did not decrease, indicating that longitudinal changes in NLR correlate with prognosis. To investigate association with tumor-immune microenvironment, 14-marker multiplex immunohistochemistry was performed to quantitatively evaluate intratumoral CD8+ T cells, helper T cells, regulatory T cells, B cells, natural killer cells, macrophages, dendritic cells, mast cells, and granulocytes. Notably, NLR at pretreatment status significantly correlated with intratumoral immune cell densities, where high NLR correlated with low lymphoid cells and high tumor associated macrophages in tissue. NLR in peripheral blood significantly correlated with myeloid to lymphoid cell ratios in tissue, suggesting the presence of association between circulating and intratumoral immune complexity profiles. This study highlights that the association between intratumoral myeloid predominance and systemic nutritional and inflammatory status might be a possible factor for resistance to immunotherapy. Understanding immune dynamics in tissue and blood during immunotherapy potentially contributes to the establishment of predictive biomarkers and monitoring for immunotherapy. Citation Format: Hiroki Morimoto, Takahiro Tsujikawa, Aya Miyagawa-Hayashino, Alisa Kimura, Sumiyo Saburi, Junichi Mitsuda, Kanako Yoshimura, Gaku Ohmura, Shigeyuki Mukudai, Hikaru Nagao, Yoichiro Sugiyama, Shibata Saya, Hiroshi Ogi, Eiichi Konishi, Kyoko Itoh, Shigeru Hirano. Neutrophil-to-lymphocyte ratio associates with intratumoral myeloid predominance and clinical outcomes of pembrolizumab in head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4453.

OBJECTIVES/HYPOTHESIS Vocal fold fibrosis remains a significant clinical challenge. Estrogens, steroid hormones predominantly responsible for secondary sexual characteristics in women, have been shown to alter wound healing and limit fibrosis, but the effects on vocal fold fibrosis are unknown. We sought to elucidate the expression of estrogen receptors and the effects of estrogens on TGF-β1 signaling in rat vocal fold fibroblasts (VFFs). STUDY DESIGN In vitro. METHODS VFFs were isolated from 10-week-old, male Sprague-Dawley rats, and estrogen receptor alpha (ERα) and G protein-coupled receptor 30 (GPR30) were examined via immunostaining and quantitative polymerase chain reaction (qPCR). VFFs were treated with estradiol (E2, 10-7 , 10-8 or 10-9 M) ± transforming growth factor beta 1 (TGF-β1, 10 ng/mL). ICI 182,780 (ICI, 10-7 M) or G36 (10-7 M) were employed as antagonists of ERα or GPR30, respectively. qPCR was employed to determine estrogen receptor-mediated effects of E2 on genes related to fibrosis. RESULTS ERα and GPR30 were expressed in VFFs at both the protein and the mRNA levels. E2 (10-7 M) did not alter Smad3, Smad7, Acta2 mRNA, or extracellular matrix related genes. However, the combination of E2 (10-8 M) and TGF-β1 significantly increased Smad7 (P = .03) and decreased Col1a1 (P = .04) compared to TGF-β1 alone; this response was negated by the combination of ICI and G36 (P = .009). CONCLUSIONS E2 regulated TGF-β1/Smad signaling via estrogen receptors in VFFs. These findings provide insight into potential mechanisms of estrogens on vocal fold injury with the goal of enhanced therapeutics for vocal fold fibrosis. LEVEL OF EVIDENCE NA Laryngoscope, 131:2285-2291, 2021.

OBJECTIVES: We aimed to examine the effect of unilateral inhibition of the medullary dorsal swallowing networks on the activities of swallowing-related cranial motor nerves and swallowing interneurons. METHODS: In 25 juvenile rats, we recorded bilateral vagal nerve activity (VNA) as well as unilateral phrenic and hypoglossal activity (HNA) during fictive swallowing elicited by electrical stimulation of the superior laryngeal nerve during control and following microinjection of the GABA agonist muscimol into the caudal dorsal medulla oblongata in a perfused brainstem preparation. In 20 animals, swallowing interneurons contralateral to the muscimol injection side were simultaneously recorded extracellularly and their firing rates were analyzed during swallowing. RESULTS: Integrated VNA and HNA to the injection side decreased to 49.0 ± 16.6% and 32.3 ± 17.9%, respectively. However, the VNA on the uninjected side showed little change after muscimol injection. Following local inhibition, 11 out of 20 contralateral swallowing interneurons showed either increased or decreased of their respective firing discharge during evoked-swallowing, while no significant changes in activity were observed in the remaining nine neurons. CONCLUSION: The neuronal networks underlying the swallowing pattern generation in the dorsal medulla mediate the ipsilateral motor outputs and modulate the contralateral activity of swallowing interneurons, suggesting that the bilateral coordination of the swallowing central pattern generator regulates the spatiotemporal organization of pharyngeal swallowing movements. LEVEL OF EVIDENCE: NA Laryngoscope, 131:2187-2198, 2021.

Objectives/hypothesis Vocal fold atrophy, scar, and sulcus reduce the vibratory function of the vocal fold mucosa, which causes severe refractory dysphonia. We have reported encouraging preliminary results using an intracordal injection of basic fibroblast growth factor (bFGF) and showed improvement in phonatory parameters and voice. The present study summarizes our experience with 100 cases of stiffened vocal folds that were treated with bFGF injections. Study design Retrospective chart review with Interstitial Review Board (IRB) approval. Methods Local injection of bFGF was performed in 100 cases of vocal fold pathology, which included 43 cases of vocal fold atrophy, 41 cases with scar, and 16 cases with sulcus. Ten micrograms of bFGF were injected into the vocal folds under topical anesthesia 4 times in each patient. Therapeutic outcomes were examined with maximum phonation time (MPT), voice handicap index-10 (VHI-10), and GRBAS scale. Results MPT, VHI-10, and GRBAS scores significantly improved in all pathology groups. An improvement on the VHI-10 greater than five points was observed in 82% of atrophy cases, 78% of scar cases, and 67% of sulcus cases. Improvement on the VHI-10 was significantly better in the atrophy group than the scar or sulcus groups. The mild/moderate cases of scar and sulcus showed better improvement than severe cases. Conclusions The current large case series indicates positive effects of intracordal injection of bFGF for improvement of voice with no severe adverse events. The effects appeared best for cases of atrophy, while the treatment of severe scar and sulcus requires further improvement. Level of evidence 4 Laryngoscope, 131:2059-2064, 2021.

Invasive fungal rhinosinusitis (FRS) is a rare but intractable infectious disease of the sinonasal region with destructive direct infiltration into surrounding tissues, such as the bone, orbit and brain, and potential dissemination to systemic organs. Symptomatic assessments and imaging are frequently not sufficiently diagnostic, and histopathological examination is essential for definite diagnosis of FRS. We herein report a case of chronic invasive FRS (CIFRS) in a 58-year-old Japanese male with end-stage diabetic nephropathy that required maintenance dialysis after graft rejection of living kidney transplantation. His initial main clinical presentation was sinus gangrene, which gradually progressed from the paranasal sinus to the nasal septum and oral palate, but not towards the intracranial or orbital region, for two months. The patient was first strongly suspected to have extranodal natural killer/T cell lymphoma (ENKTL), nasal type, a subtype of malignant lymphoma, based on the macroscopic appearance of the gangrene, expansion pattern and high serum soluble interleukin-2 level; however, repeated biopsies and eventual resection led to diagnosis of CIFRS due to Aspergillus niger and Mucor. The disease was improved by surgical resection in combination with antifungal pharmacologic treatment with liposomal amphotericin B and voriconazole. CIFRS typically occurs in immunocompetent patients and shows intracranial progression, but this case shows that atypical CIFRS with an uncommon expansion pattern can occur in an immunodeficient patient.

Dia1, which belongs to the diaphanous-related formin family, influences a variety of cellular processes through straight actin elongation activity. Recently, novel DIA1 mutants such as p.R1213X (p.R1204X) and p.A265S, have been reported to cause an autosomal dominant sensorineural hearing loss (DFNA1). Additionally, active DIA1 mutants induce progressive hearing loss in a gain-of-function manner. However, the subcellular localization and pathological function of DIA1(R1213X/R1204X) remains unknown. In the present study, we demonstrated the localization of endogenous Dia1 and the constitutively active DIA1 mutant in the cochlea, using transgenic mice expressing FLAG-tagged DIA1(R1204X) (DIA1-TG). Endogenous Dia1 and the DIA1 mutant were regionally expressed at the organ of Corti and the spiral ganglion from early life; alongside cochlear maturation, they became localized at the apical junctional complexes (AJCs) between hair cells (HCs) and supporting cells (SCs). To investigate HC vulnerability in the DIA1-TG mice, we exposed 4-week-old mice to moderate noise, which induced temporary threshold shifts with cochlear synaptopathy and ultrastructural changes in stereocilia 4 weeks post noise exposure. Furthermore, we established a knock-in (KI) mouse line expressing AcGFP-tagged DIA1(R1213X) (DIA1-KI) and confirmed mutant localization at AJCs and the tips of stereocilia in HCs. In MDCKAcGFP-DIA1(R1213X) cells with stable expression of AcGFP-DIA1(R1213X), AcGFP-DIA1(R1213X) revealed marked localization at microvilli on the apical surface of cells and decreased localization at cell-cell junctions. The DIA1-TG mice demonstrated hazy and ruffled circumferential actin belts at AJCs and abnormal stereocilia accompanied with HC loss at 5 months of age. In conclusion, Dia1 plays a pivotal role in the development and maintenance of AJCs and stereocilia, ensuring cochlear and HC integrity. Subclinical/latent vulnerability of HCs may be the cause of progressive hearing loss in DFNA1 patients, thus suggesting new therapeutic targets for preventing HC degeneration and progressive hearing loss associated with DFNA1.