ABCC1 deficiency potentiated noise-induced hearing loss in mice by impairing cochlear antioxidant capacity.

The ABCC1 gene belongs to the ATP-binding cassette membrane transporter superfamily, which plays a crucial role in the efflux of various endogenous and exogenous substances. Mutations in ABCC1 can result in autosomal dominant hearing loss. However, the specific roles of ABCC1 in auditory function are not fully understood. Through immunofluorescence, we found that ABCC1 was expressed in microvascular endothelial cells (ECs) of the stria vascularis (StV) in the murine cochlea. Then, an Abcc1 knockout mouse model was established by using CRISPR/Cas9 technology to elucidate the role of ABCC1 in the inner ear. The ABR threshold did not significantly differ between WT and Abcc1-/- mice at any age studied. After noise exposure, the ABR thresholds of the WT and Abcc1-/- mice were significantly elevated. Interestingly, after 14 days of noise exposure, ABR thresholds largely returned to pre-exposure levels in WT mice but not in Abcc1-/- mice. Our subsequent experiments showed that microvascular integrity in the StV was compromised and that the number of outer hair cells and the number of ribbons were significantly decreased in the cochleae of Abcc1-/- mice post-exposure. Besides, the production of ROS and the accumulation of 4-HNE significantly increased. Furthermore, StV microvascular ECs were cultured to elucidate the role of ABCC1 in these cells under glucose oxidase challenge. Notably, 30 U/L glucose oxidase (GO) induced severe oxidative stress damage in Abcc1-/- cells. Compared with WT cells, the ROS and 4-HNE levels and the apoptotic rate were significantly elevated in Abcc1-/- cells. In addition, the reduced GSH/GSSG ratio was significantly decreased in Abcc1-/- cells after GO treatment. Taken together, Abcc1-/- mice are more susceptible to noise-induced hearing loss, possibly because ABCC1 knockdown compromises the GSH antioxidant system of StV ECs. The exogenous antioxidant N-acetylcysteine (NAC) may protect against oxidative damage in Abcc1-/- murine cochleae and ECs.

[Advances in research on treatment of tympanosclerosis].

Tympanosclerosis is the hyaline degeneration and calcium deposition of the lamina propria of tympanic membrane and the submucosa of middle ear under long-term chronic inflammatory stimulation. At present, treatment primarily involves the surgical removal of sclerotic foci and reconstruction of auditory ossicular chain. However, excision of sclerotic lesions near critical structures like the facial nerve canal and vestibular window may result in complications like facial paralysis, vertigo, and sensorineural hearing loss. Developing safer and more effective treatments for tympanosclerosis has become an international research focus. Recent years have seen novel explorations in the treatment of tympanosclerosis. Therefore, this article reviews the latest advancements in research on the treatment of tympanosclerosis.

[Application and efficacy analysis of tympanic cartilage shaping device in endoscopic type â tympanoplasty].

Objective:To study the feasibility and efficacy of using a tympanic cartilage shaping device in endoscopic type Ⅰ tympanoplasty. Methods:A tympanic cartilage shaper was designed and manufactured by measuring tympanic membrane dimensions with HRCT imaging for cutting and shaping cartilage to repair the tympanic membrane. From August 2019 to October 2021, 66 patients（72 ears） with chronic suppurative otitis media in Xiangya Hospital underwent endoscopic type Ⅰ tympanoplasty with this tympanic cartilage shaping device, and were observed the tympanic membrane healing and hearing recovery effect after surgery. Postoperative follow-up ranged from 3-24 months, with an average of 9 months. The data were analyzed by the SPSS 26.0 software. Results:According to the imaging measurements, tympanic pars tensa width（8.60±0.20） mm, height（8.64±0.19） mm, design and manufacture a cylindrical cartilage shaping device with inner diameter 8.60 mm. After tympanoplasty, the healing rate of tympanic membrane was 100%; The average air-bone gap before surgery was（23.10±7.33） dB, then（14.30±6.40） dB 1 month after surgery, which were significant reduced compared with those before surgery. The average air-bone gap was（14.30±6.40） dB 3 month after surgery compared with 1 month after surgery, the difference was also statistically significant（t=6.630, P<0.05）. Conclusion:The tympanic membrane cartilage shaper shaping cartilage in endoscopic tympanoplasty is simple, stable and reliable, which can reduce the time of graft cartilage processing, improve the efficiency of surgery, and restore the tympanic membrane morphology and function in the postoperative period.

Identification of a family with van der Hoeve's syndrome harboring a novel COL1A1 mutation and generation of patient-derived iPSC lines and CRISPR/Cas9-corrected isogenic iPSCs.

Van der Hoeve's syndrome, also known as osteogenesis imperfecta (OI), is a genetic connective tissue disorder characterized by fragile, fracture-prone bone and hearing loss. The disease is caused by a gene mutation in one of the two type I collagen genes COL1A1 or COL1A2. In this study, we identified a novel frameshift mutation of the COL1A1 gene (c.1607delG) in a family with OI using whole-exome sequencing, bioinformatics analysis and Sanger sequencing. This mutation may lead to the deletion of a portion of exon 23 and the generation of a premature stop codon in the COL1A1 gene. To further investigate the impact of this mutation, we established two induced pluripotent stem cell (iPSC) lines from peripheral blood mononuclear cells of OI patients carrying a novel mutation in the COL1A1 gene. Osteoblasts (OB) derived from OI-iPSCs exhibited reduced production of type I collagen and diminished ability to differentiate into osteoblasts. Using a CRISPR-based homology-directed repair strategy, we corrected the OI disease-causing COL1A1 novel mutations in iPSCs generated from an affected individual. Our results demonstrated that the diminished expression of type I collagen and osteogenic potential were enhanced in OB induced from corrected OI-iPSCs compared to those from OI-iPSCs. Overall, our results provide new insights into the genetic basis of Van der Hoeve's syndrome and highlight the potential of iPSC technology for disease modeling and therapeutic development.

PAX3 mutation suppress otic progenitors proliferation and induce apoptosis by inhibiting WNT1/ß-catenin signaling pathway in WS1 patient iPSC-derived inner ear organoids.

Waardenburg syndrome type 1 (WS1) is a hereditary disease mainly characterized by sensorineural hearing loss, dystopia canthorum, and pigmentary defects. To elucidate molecular mechanisms underlying PAX3-associated hearing loss, we developed inner ear organoids model using induced pluripotent stem cells (iPSCs) derived from WS1 patient and healthy individual. Our results revealed a significant reduction in the size of inner ear organoids, accompanied by an increased level of apoptosis in organoids derived from WS1 patient-iPSCs carrying PAX3 c.214A > G. Transcriptome profiling analysis by RNA-seq indicated that inner ear organoids from WS1 patients were associated with suppression of inner ear development and WNT signaling pathway. Furthermore, the upregulation of the WNT1/ß-catenin pathway which was achieved through the correction of PAX3 isogenic mutant iPSCs using CRISPR/Cas9, contributed to an increased size of inner ear organoids and a reduction in apoptosis. Together, our results provide insight into the underlying mechanisms of hearing loss in WS.

Modeling of pigmentation disorders associated with MITF mutation in Waardenburg syndrome revealed an impaired melanogenesis pathway in iPS-derived melanocytes.

Waardenburg Syndrome (WS) is a rare genetic disorder that leads to congenital hearing loss and pigmentation defects. Microphthalmia-associated transcription factor (MITF) is one of its significant pathogenic genes. Despite the comprehensive investigation in animal models, the pathogenic mechanism is still poorly described in humans due to difficulties accessing embryonic tissues. In this work, we used induced pluripotent stem cells derived from a WS patient carrying a heterozygous mutation in the MITF gene c.626A>T (p.His209Leu), and differentiated toward melanocyte lineage, which is the most affected cell type involved in WS. Compared with the wild-type cell line, the MITFmut cell line showed a reduced expression of the characteristic melanocyte-related genes and a lesser proportion of mature, fully pigmented melanosomes. The transcriptome analysis also revealed widespread gene expression changes at the melanocyte stage in the MITFmut cell line. The differentially expressed genes were enriched in melanogenesis and cell proliferation-related pathways. Interestingly, ion transport-related genes also showed a significant difference in MITFmut -induced melanocytes, indicating that the MITF mutant may lead to the dysfunction of potassium channels and transporters produced by intermediate cells in the cochlea, further causing the associated phenotype of deafness. Altogether, our study provides valuable insights into how MITF mutation affects WS patients, which might result in defective melanocyte development and the related phenotype based on the patient-derived iPSC model.

Susceptibility of immature spiral ganglion neurons to aminoglycoside-induced ototoxicity is mediated by the TRPV1 channel in mice.

Aminoglycoside antibiotics are among the most common agents that can cause sensorineural hearing loss. From clinical experience, premature babies, whose inner ear is still developing, are more susceptible to aminoglycoside-induced ototoxicity, which is echoed by our previous study carried out in organotypic cultures. This study aimed to investigate whether a nonselective cation channel, TRPV1, contributes to the susceptibility of immature spiral ganglion neurons (SGNs) to the damage caused by aminoglycosides. Through western blotting and immunofluorescence, we found that the TRPV1 expression levels were much higher in immature SGNs than in their mature counterparts. In postnatal day 7 cochlear organotypic cultures, AMG-517 reduced reactive oxygen species generation and inhibited SGN apoptosis under aminoglycoside challenge. However, in adult mice, AMG-517 did not ameliorate the ABR threshold increase at high frequencies (16 kHz and 32 kHz) after aminoglycoside administration, and the SGNs within the cochleae had no morphological changes. By further regulating the function of TRPV1 in primary cultured SGNs with its inhibitor AMG-517 and agonist capsaicin, we demonstrated that TRPV1 is a major channel for aminoglycoside uptake: AMG-517 can significantly reduce, while capsaicin can significantly increase, the uptake of GTTR. In addition, TRPV1 knockdown in SGNs can also significantly reduce the uptake of GTTR. Taken together, our results demonstrated that aminoglycosides can directly enter immature SGNs through the TRPV1 channel. High expression of TRPV1 contributes to the susceptibility of immature SGNs to aminoglycoside-induced damage. The TRPV1 inhibitor AMG-517 has the potential to be a therapeutic agent for preventing aminoglycoside-induced ototoxicity in immature SGNs.

A Novel EYA1 Mutation Causing Alternative RNA Splicing in a Chinese Family With Branchio-Oto Syndrome: Implications for Molecular Diagnosis and Clinical Application.

OBJECTIVES: Branchio-oto syndrome (BOS) primarily manifests as hearing loss, preauricular pits, and branchial defects. EYA1 is the most common pathogenic gene, and splicing mutations account for a substantial proportion of cases. However, few studies have addressed the structural changes in the protein caused by splicing mutations and potential pathogenic factors, and several studies have shown that middle-ear surgery has limited effectiveness in improving hearing in these patients. BOS has also been relatively infrequently reported in the Chinese population. This study explored the genetic etiology in the family of a proband with BOS and provided clinical treatment to improve the patient's hearing. METHODS: We collected detailed clinical features and peripheral blood samples from the patients and unaffected individuals within the family. Pathogenic mutations were identified by whole-exome sequencing and cosegregation analysis and classified according to the American College of Medical Genetics and Genomics guidelines. Alternative splicing was verified through a minigene assay. The predicted three-dimensional protein structure and biochemical experiments were used to investigate the pathogenicity of the mutation. The proband underwent middle-ear surgery and was followed up at 1 month and 6 months postoperatively to monitor auditory improvement. RESULTS: A novel heterozygous EYA1 splicing variant (c.1050+4 A>C) was identified and classified as pathogenic (PVS1(RNA), PM2, PP1). Skipping of exon 11 of the EYA1 pre-mRNA was confirmed using a minigene assay. This mutation may impair EYA1-SIX1 interactions, as shown by an immunoprecipitation assay. The EYA1-Mut protein exhibited cellular mislocalization and decreased protein expression in cytological experiments. Middle-ear surgery significantly improved hearing loss caused by bone-conduction abnormalities in the proband. CONCLUSION: We reported a novel splicing variant of EYA1 in a Chinese family with BOS and revealed the potential molecular pathogenic mechanism. The significant hearing improvement observed in the proband after middle-ear surgery provides a reference for auditory rehabilitation in similar patients.

Gene regulation analysis of patient-derived iPSCs and its CRISPR-corrected control provides a new tool for studying perturbations of ELMOD3 c.512A>G mutation during the development of inherited hearing loss.

The ELMOD3 gene is implicated in causing autosomal recessive/dominant non-syndromic hearing loss in humans. However, the etiology has yet to be completely elucidated. In this study, we generated a patient-derived iPSC line carrying ELMOD3 c.512A>G mutation. In addition, the patient-derived iPSC line was corrected by CRISPR/Cas9 genome editing system. Then we applied RNA sequencing profiling to compare the patient-derived iPSC line with different controls, respectively (the healthy sibling-derived iPSCs and the CRISPR/Cas9 corrected iPSCs). Functional enrichment and PPI network analysis revealed that differentially expressed genes (DEGs) were enriched in the gene ontology, such as sensory epithelial development, intermediate filament cytoskeleton organization, and the regulation of ion transmembrane transport. Our current work provided a new tool for studying how disruption of ELMOD3 mechanistically drives hearing loss.

Clinical characteristics and surgical strategy of glomus tympanicum tumors. / 鼓室体瘤的临床特征及手术策略.

OBJECTIVES: To summarize the clinical characteristics of glomus tympanicum tumors, and to explore the surgical methods and the strategy for auditory protection. METHODS: Ten cases (ears) of glomus tympanicum tumors were collected from the Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University from August 2014 to February 2022. All patients underwent endoscopic or microscopic surgery to achieve total removal of the tumor, followed up for 3 months to 8 years. We summarized and analyzed its clinical characteristics, compared the preoperative and postoperative hearing levels of patients, and made a retrospective summary of the surgical methods and the strategy for auditory protection. RESULTS: Ten patients were all female at (49.50±8.00) years old. Their medical history ranged from 15 days to 6 years. Seven patients complained of pulsatile tinnitus, and 80% (8/10) of the affected ears suffered different degrees of hearing loss. According to the modified Fisch & Mattox classification of glomus tympanicum tumors, 3 ears (30%) of 10 ears were A1, 2 ears (20%) were A2 and 5 ears (50%) were B1. In all 10 cases (ears), hearing was improved in 3 cases, bone gas conductance was maintained in 6 cases, and hearing was slightly decreased in 1 case. The difference of bone gas conductance was 0-10 dB in 7 cases (ears) after operation, and 10-20 dB in 3 cases (ears). There was no significant difference in the average air conduction hearing threshold, bone conduction hearing threshold and air-bone conduction difference between before and after operation (all P>0.05). All cases had no postoperative complications, and the external auditory canal and the incision behind the ear healed well. There was no recurrence after follow-up. CONCLUSIONS: Glomus tympanicum tumor is easy to bleed, so it is a challenge for total tumor resection and hearing function protection during operation. For type A and type B1 tumors, they can be completely removed under the condition of keeping the tympanic membrane and the ossicular chain. At the same time, the postoperative hearing function can be preserved, and even the hearing can be improved.

Research and application progress in deep learning in otology. / æ·±åº¦å­¦ä¹ åœ¨è€³ç§‘å­¦ä¸­çš„ç ”ç©¶ä¸Žåº”ç”¨è¿›å±•.

With the optimization of deep learning algorithms and the accumulation of medical big data, deep learning technology has been widely applied in research in various fields of otology in recent years. At present, research on deep learning in otology is combined with a variety of data such as endoscopy, temporal bone images, audiograms, and intraoperative images, which involves diagnosis of otologic diseases (including auricular malformations, external auditory canal diseases, middle ear diseases, and inner ear diseases), treatment (guiding medication and surgical planning), and prognosis prediction (involving hearing regression and speech learning). According to the type of data and the purpose of the study (disease diagnosis, treatment and prognosis), the different neural network models can be used to take advantage of their algorithms, and the deep learning can be a good aid in treating otologic diseases. The deep learning has a good applicable prospect in the clinical diagnosis and treatment of otologic diseases, which can play a certain role in promoting the development of deep learning combined with intelligent medicine.

Short-term effects of intravenous batroxobin in treatment of sudden sensorineural hearing loss: a propensity score-matched study.

Background: Sudden sensorineural hearing loss (SSNHL) can cause great panic in patients. Whether it is advantageous to add intravenous batroxobin in the treatment of SSNHL remains to be determined. This study aimed to compare the short-term efficacy of therapy combined with intravenous batroxobin and that without intravenous batroxobin in SSNHL patients. Methods: This retrospective study harvested the data of SSNHL patients hospitalized in our department from January 2008 to April 2021. The hearing levels on the admitted day (before treatment) and the discharge day were considered pre-treatment hearing and post-treatment hearing, respectively. The hearing gain was the difference value of pre-treatment hearing and post-treatment hearing. We used Siegel's criteria and the Chinese Medical Association of Otolaryngology (CMAO) criteria to evaluate hearing recovery. The complete recovery rate, overall effective rate, and hearing gain at each frequency were considered outcomes. Propensity score matching (PSM) was conducted to balance the baseline characteristics between the batroxobin group and the non-batroxobin group. Sensitivity analysis was carried out in flat-type and total-deafness SSNHL patients. Results: During the study period, 657 patients with SSNHL were admitted to our department. Among them, a total of 274 patients met the enrolled criteria of our study. After PSM, 162 patients (81 in each group) were included in the analysis. Once the hospitalized treatment was completed, the patients would be discharged the next day. Logistic regression analysis of the propensity score-matched cohort indicated that both the complete recovery rates [Siegel's criteria, OR: 0.734, 95% CI: 0.368-1.466, p = 0.381; CMAO criteria, OR: 0.879, 95% CI: 0.435-1.777, p = 0.720] and the overall effective rates [Siegel's criteria and CMAO criteria, OR: 0.741, 95% CI: 0.399-1.378, p = 0.344] were not significantly different between the two treatment groups. Sensitivity analysis has shown similar results. For flat-type and total-deafness SSNHL patients, no significant difference was found in post-treatment hearing gain at each frequency between the two groups after PSM. Conclusion: There was no significant difference in short-term hearing outcomes between treatment with batroxobin and treatment without batroxobin in SSNHL patients by Siegel's and CMAO criteria after PSM. Future studies for better therapy regimens of SSNHL are still needed.

[Analysis of therapeutic effect of tympanoplasty type â in elderly patients with chronic suppurative otitis media].

Objective:To summarize the clinical characteristics of elderly patients with chronic suppurative otitis media who underwent type Ⅰ tympanoplasty, and to analyze for the first time the efficacy of type Ⅰtympanoplasty in elderly patients from multiple perspectives of medical data and patient evaluation, so as to provide reference for doctors and patients to make rational decisions on treatment methods. Methods:Forty-four elderly patients（45 ears） who underwent type Ⅰtympanoplasty from May 2016 to February 2022 were retrospectively analyzed, and were followed up for 6 months to 3 years. To analyze the clinical characteristics of patients, summarize the success rate of graft, and compare the hearing level of patients before and after surgery. The patients' quality of life before and after operation was evaluated by Chronic Ear Survey, and the scores obtained were statistically analyzed. Results:Of the 44 patients（45 ears）, 22.22%（10/45） of the ears had predisposing factors. The percentage of hearing loss, ear pus and tinnitus were 91.11%（41/45）, 88.89%（40/45） and 42.22%（19/45）, respectively. Mixed deafness accounted for 55.56%（25/45）. 66.67%（30/45） patients were diagnosed as tympanosclerosis by operation. The graft success rate was 97.78%. There was no significant difference in bone conduction hearing threshold before and after surgery, but there was significant difference in air conduction hearing threshold and air bone conduction difference. The scores of "activity restriction", "symptom", "medical resource utilization" and their total scores of the preoperative and postoperative were statistically different. Hypertension or diabetes had no significant effect on the efficacy of type Ⅰ tympanoplasty in elderly patients. Conclusion:Type Ⅰtympanoplasty is safe and effective in elderly patients, and the quality of life of patients after surgery is significantly improved. It is necessary to increase the awareness of elderly patients to seek medical advice and use surgical methods reasonably to treat chronic suppurative otitis media.

A comprehensive genotype-phenotype evaluation of eight Chinese probands with Waardenburg syndrome.

BACKGROUND: Waardenburg syndrome (WS) is the most common form of syndromic deafness with phenotypic and genetic heterogeneity in the Chinese population. This study aimed to clarify the clinical characteristics and the genetic cause in eight Chinese WS families (including three familial and five sporadic cases). Further genotype-phenotype relationships were also investigated. METHODS: All probands underwent screening for the known WS-related genes including PAX3, SOX10, MITF, EDNRB, EDN3, and SNAI2 using next-generation sequencing to identify disease-causing genes. Further validation using Sanger sequencing was performed. Relevant findings for the associated genotype-phenotype from previous literature were retrospectively analyzed. RESULT: Disease-causing variants were detected in all eight probands by molecular genetic analysis of the WS genes (SOX10(NM_006941.4): c.544_557del, c.553 C > T, c.762delA, c.336G > A; MITF(NM_000248.3): c.626 A > T; PAX3(NM_181459.4): c.838delG, c.452-2 A > G, c.214 A > G). Six mutations (SOX10:c.553 C > T, c.544_557del, c.762delA; PAX3: c.838delG, c.214 A > G; MITF:c.626 A > T) were first reported. Clinical evaluation revealed prominent phenotypic variability in these WS patients. Twelve WS1 cases and five WS2 cases were diagnosed in total. Two probands with SOX10 mutations developed progressive changes in iris color with age, returning from pale blue at birth to normal tan. Additionally, one proband had a renal malformation (horseshoe kidneys).All cases were first described as WS cases. Congenital inner ear malformations were more common, and semicircular malformations were exclusively observed in probands with SOX10 mutations. Unilateral hearing loss occurred more often in cases with PAX3 mutations. CONCLUSION: Our findings helped illuminate the phenotypic and genotypic spectrum of WS in Chinese populations and could contribute to better genetic counseling of WS.

Establishment of two iPSC lines from healthy donor with heterozygous mutation in the SLC26A4 gene.

The human induced pluripotent stem cell (iPSC) lines, CSUXHEi001-A and CSUXHEi002-A, were generated from peripheral blood mononuclear cells (PBMCs). The donors were couple and each of them has a heterozygous mutation in the SLC26A4 gene. It manifests in their children as Enlarged vestibular aqueduct (EVA). The use of iPSC will allow describing the early stages of hearing loss, which is undoubtedly relevant for identifying key stages of development at which phenotypic manifestations of mutations in the SLC26A4 gene are found.

Establishment of a risk index for early complications after trans-canal endoscopic ear surgery.

PURPOSE: This study aimed to determine the risk factors associated with early postoperative complications of trans-canal endoscopic ear surgery (TEES), then to develop a risk index. MATERIALS AND METHODS: This single-institution retrospective study reviewed TEESs from January 1, 2017, to December 31, 2019 in a tertiary hospital. In the derivation cohort, univariable and multivariable logistic regression were performed to identify factors significantly associated with early postoperative complications of TEES. Then these parameters were integrated into a trans-canal endoscopic ear surgery risk index (TEESRI). The performance of TEESRI was compared with that of the American Society of Anesthesiologists (ASA) classification using the validation cohort. RESULTS: 932 TEESs were enrolled in total and 151 (16.2%) developed early postoperative complications. In the derivation set, 8 factors including state of the opposite ear and presence of nasal or pharyngeal diseases were found to be independently associated with the occurrence of early postoperative complications on multivariable regression analysis [area under the curve (AUC), 0.806; 95% confidence interval (CI), 0.765-0.848]. Using the validation cohort, the AUC of the TEESRI was 0.776 [95%CI, 0.711-0.842], with a sensitivity of 82.2% and specificity of 65.5%, while the AUC of the ASA classification was 0.512 (95%CI, 0.421-0.603). The TEESRI outperformed the ASA classification when evaluating the risk for early postoperative complications of TEES. CONCLUSIONS: Based on the 8 risk factors, the TEESRI was established with satisfactory predicting capacity. Surgeons should pay extra attention to the risk factors in the TEESRI, when treating patients.

Genetic insights, disease mechanisms, and biological therapeutics for Waardenburg syndrome.

Waardenburg syndrome (WS), also known as auditory-pigmentary syndrome, is the most common cause of syndromic hearing loss (HL), which accounts for approximately 2-5% of all patients with congenital hearing loss. WS is classified into four subtypes depending on the clinical phenotypes. Currently, pathogenic mutations of PAX3, MITF, SOX10, EDN3, EDNRB or SNAI2 are associated with different subtypes of WS. Although supportive techniques like hearing aids, cochlear implants, or other assistive listening devices can alleviate the HL symptom, there is no cure for WS to date. Recently major progress has been achieved in preclinical studies of genetic HL in animal models, including gene delivery and stem cell replacement therapies. This review focuses on the current understandings of pathogenic mechanisms and potential biological therapeutic approaches for HL in WS, providing strategies and directions for implementing WS biological therapies, as well as possible problems to be faced, in the future.

[New deafness gene: Progress of research on ABCC1 in biological barriers].

ABCC1 gene is expressed in various tissues and organs of the human body, and can transport substrates including drugs, heavy metals, toxic substances and organic anions. Previous research on ABCC1 gene has mostly focused on tumor multidrug resistance. Recently, ABCC1 has been proposed as a candidate gene for hereditary hearing impairment, which has attracted much attention. ABCC1-associated deafness may be related to its role in biological barriers. This article has summarized recent progress in the study of the role of ABCC1 in the blood-testis barrier, placental barrier, blood-brain barrier, blood-labyrinth barrier, which may provide insight into its biological functions.

A Model of Waardenburg Syndrome Using Patient-Derived iPSCs With a SOX10 Mutation Displays Compromised Maturation and Function of the Neural Crest That Involves Inner Ear Development.

Waardenburg syndrome (WS) is an autosomal dominant inherited disorder that is characterized by sensorineural hearing loss and abnormal pigmentation. SOX10 is one of its main pathogenicity genes. The generation of patient-specific induced pluripotent stem cells (iPSCs) is an efficient means to investigate the mechanisms of inherited human disease. In our work, we set up an iPSC line derived from a WS patient with SOX10 mutation and differentiated into neural crest cells (NCCs), a key cell type involved in inner ear development. Compared with control-derived iPSCs, the SOX10 mutant iPSCs showed significantly decreased efficiency of development and differentiation potential at the stage of NCCs. After that, we carried out high-throughput RNA-seq and evaluated the transcriptional misregulation at every stage. Transcriptome analysis of differentiated NCCs showed widespread gene expression alterations, and the differentially expressed genes (DEGs) were enriched in gene ontology terms of neuron migration, skeletal system development, and multicellular organism development, indicating that SOX10 has a pivotal part in the differentiation of NCCs. It's worth noting that, a significant enrichment among the nominal DEGs for genes implicated in inner ear development was found, as well as several genes connected to the inner ear morphogenesis. Based on the protein-protein interaction network, we chose four candidate genes that could be regulated by SOX10 in inner ear development, namely, BMP2, LGR5, GBX2, and GATA3. In conclusion, SOX10 deficiency in this WS subject had a significant impact on the gene expression patterns throughout NCC development in the iPSC model. The DEGs most significantly enriched in inner ear development and morphogenesis may assist in identifying the underlying basis for the inner ear malformation in subjects with WS.

A nonsense TMEM43 variant leads to disruption of connexin-linked function and autosomal dominant auditory neuropathy spectrum disorder.

Genes that are primarily expressed in cochlear glia-like supporting cells (GLSs) have not been clearly associated with progressive deafness. Herein, we present a deafness locus mapped to chromosome 3p25.1 and an auditory neuropathy spectrum disorder (ANSD) gene, TMEM43, mainly expressed in GLSs. We identify p.(Arg372Ter) of TMEM43 by linkage analysis and exome sequencing in two large Asian families segregating ANSD, which is characterized by inability to discriminate speech despite preserved sensitivity to sound. The knock-in mouse with the p.(Arg372Ter) variant recapitulates a progressive hearing loss with histological abnormalities in GLSs. Mechanistically, TMEM43 interacts with the Connexin26 and Connexin30 gap junction channels, disrupting the passive conductance current in GLSs in a dominant-negative fashion when the p.(Arg372Ter) variant is introduced. Based on these mechanistic insights, cochlear implant was performed on three subjects, and speech discrimination was successfully restored. Our study highlights a pathological role of cochlear GLSs by identifying a deafness gene and its causal relationship with ANSD.