Auditory Research publications

Kanamycin (KM), a widely used aminoglycoside antibiotic, is limited by its ototoxic side effects, primarily targeting cochlear outer hair cells (OHCs) and leading to irreversible sensorineural hearing loss. Our previous work showed that silencing AMP‐activated protein kinase alpha 1 (AMPKα1) prevents noise‐induced hearing loss through a redox‐sensitive regulatory mechanism. Given that both noise‐induced and aminoglycoside‐induced hearing loss share oxidative stress as a key pathological feature, we tested whether AMPKα1 silencing could mitigate KM‐induced damage using an acute ototoxic model combining KM with furosemide (KM + FU). KM + FU exposure markedly increased AMPKα phosphorylation at Thr172. Targeted siRNA‐mediated silencing via posterior semicircular canal delivery in CBA/J mice significantly reduced AMPKα1 expression in OHCs and effectively prevented KM + FU‐induced OHC loss and hearing impairment. This preventive effect was independent of stria vascularis permeability or cochlear KM uptake. These findings identify AMPKα as a contributor to KM + FU‐induced acute ototoxicity and suggest that its inhibition may be a promising strategy for hearing preservation.

Background Stem cell therapy offers promise for the neurodegenerative diseases and has been explored for sensorineural hearing loss (SNHL). However, effective cell delivery strategies remain a critical challenge for SNHL treatment. Methods To address this need, we established an ouabain‐induced SGN injured hearing loss model in rat and evaluated a novel transplantation strategy targeting the cochlear nerve surface via posterior occipital approach, designed to minimize cochlear structural damage and facilitate targeted cell delivery to Rosenthal's canal (RC). The temporal changes in glial cell densities within RC revealed a progressively deteriorating neural microenvironment, supporting early‐stage intervention. Accordingly, hair follicle‐derived neural crest stem cell (HFNCSC) transplantation was performed 3 or 4 days after modeling via two approaches: cochlear nerve surface transplantation (CNT) and round window transplantation (RWT). Results CNT resulted in significant improvements in auditory function, as evidenced by reduced auditory brainstem response (ABR) thresholds, shortened wave I latencies, and preserved wave I amplitudes post‐transplantation. Transplanted cells were distributed along the nerve trunk and within RC. In contrast, RWT failed to improve auditory function and caused cochlear structural damage, with widespread cell dispersion in cochlear fluids. Notably, the CNT group exhibited significantly higher densities of TUJ1‐positive neuron‐like cells and glial cells in the RC, accompanied by enhanced myelin basic protein expression suggestive of remyelination. No such improvements were observed in the RWT group. Conclusions These findings suggest that cochlear nerve surface transplantation enhances stem cell survival and auditory function recovery, and represents a promising delivery approach for stem cell‐based therapy of SGN‐related hearing loss.

Perceptual entrainment and temporal prediction aid speech perception in both quiet and noisy environments. Isochronous, periodic auditory rhythmic cues facilitate neural entrainment and temporal expectations which can benefit encoding and perception of target speech. However, most studies using isochronous cues confound periodicity with predictability. To this end, we characterized how systematic changes in the acoustic dimensions of stimulus rate, target phase, periodicity, and predictably of an entraining sound precursor impact the subsequent identification of concurrent speech targets. Target concurrent vowel pairs were preceded by rhythmic woodblock cues which were either periodic-predictable (PP, isochronous rhythm), aperiodic-predictable (AP, accelerating rhythm), or aperiodic-unpredictable (AU, random rhythm). The number of pulses per rhythm was roved to further manipulate predictability. Stimuli also varied in presentation rate (2.5, 4.5, 6.5 Hz) and target speech phase (in-phase, 0°; out-of-phase, –90°, 180°) relative to the preceding entraining rhythm. We also measured participants’ musical pulse continuation and standardized speech-in-noise perception abilities. We did not observe any effects of stimulus rhythm, rate, or target phase on target speech identification accuracy. However, reaction times were slowest at the nominal speech rate (4.5 Hz) and were most disrupted by out-of-phase presentations following the PP rhythm. Double-vowel task performance was associated with stronger musical pulse continuation abilities, but not speech-in-noise perception. Our results support the notion that perceptual entrainment benefits from rhythmic cues rely on top-down processing and thus are relatively muted when stimulus predictability is unknown. Additionally, we find that individual differences in musical pulse perception may underlie benefits of rhythmic cueing on subsequent speech perception.

The neural response of the brainstem to brief sounds, known as the auditory brainstem response (ABR), is widely employed in the laboratory and the clinic to diagnose hearing loss. Current ABR approaches are limited to analyzing the average ABR to hundreds of stimulus trials. Historically, trial-by-trial ABR analysis has not been possible owing to each trial's small signal-to-noise ratio. Here we overcome this limitation and show how to score individual ABR trials. We use the distribution of individual-trial ABR scores to define thresholds, which we call auditory brainstem detection (ABD) thresholds, and to assess suprathreshold hearing. Scores based on individual-trial amplitude and similarity produce lower ABD thresholds than scores based on individual-trial amplitude alone. Our method enables us to rank the suprathreshold hearing of individual subjects. Despite having normal ABR thresholds, some subjects appear to have suprathreshold hearing deficits.

Hereditary hearing loss, the most prevalent genetic sensory disorder, lacks approved pharmacological therapies and represents a compelling target for gene correction. Pathogenic variants in KCNQ4 account for ~9.5% of autosomal dominant nonsyndromic cases. Prior gene-editing strategies disrupting mutant alleles have failed to achieve durable auditory rescue. Here we employed a knock-in mouse model harboring the human KCNQ4 c.961 G > A (p.G321S) mutation to evaluate precise base editing. Dual-AAV delivery of the adenine base editor ABE8e achieved 21.4–28.9% correction in the organ of Corti—the highest efficiency reported for genetic hearing loss. A dose-dependent therapeutic window emerged: higher doses promoted rapid recovery, whereas optimized lower doses minimized long-term toxicity and sustained functional benefit for at least 32 weeks. Treatment reduced auditory brainstem response thresholds by up to 49.09 dB SPL at optimal frequencies, mitigated degeneration of hair cells, spiral ganglion neurons, and auditory nerve fibers, and partially restored outer hair cell electrophysiology. These findings demonstrate the durability of precise mutation correction over allele-disruptive approaches and support clinical translation for KCNQ4 -associated hearing loss.

Hearing is the largest modifiable mid-life risk factor for Alzheimer's disease (AD), yet its link to dementia remains unclear. We identified a neurophysiological biomarker of AD risk using the non-invasive, rapidly acquired, and clinically translatable auditory brainstem response (ABR) in normal hearing knock-in rats (Swedish familial AD risk variant to Amyloid precursor protein, AppS; male and female). Human ABRs have been proposed as a biomarker for AD and related dementias. The novel metric reported here is derived from multidimensional parametric feature extraction on the distribution statistics of repeated single-trial ABR traces. We report accurate prediction of genetic risk for AD risk in young and aged rats: AppS separate clearly from healthy humanized (AppH) in sex- and age-dependent manners. Notably, auditory learning during young adulthood shifted the AppS ABR signature towards a healthy AppH-like state that maintained over time into older age. Altogether the findings support the utility of the ABR to track disease state, progression, and effects of intervention, and point to a central neural generator of auditory dysfunction related to AD risk. ABRs could provide a very early biomarker for detection of AD risk and used to test the synergy of auditory and cognitive functions in human dementia.

SLC26A4 is a major causative gene for hereditary hearing loss, its mutation spectrum shows pronounced population specificity. In Chinese populations, patients predominantly carry biallelic mutations, and compound heterozygous genotypes are prevalent, which results in a wide spectrum of auditory phenotypes. However, how different alleles interact within these contexts to shape phenotypic variability remains poorly understood. We employed cellular and mouse models to explore the allele-specific mechanisms associated with two novel mutations, a frameshift mutation and a missense mutation, in compound heterozygous that share the same splice-site pathogenic allele. In vitro, wild-type (WT) and mutant (c.574delC, c.1211C>A) SLC26A4 constructs were expressed in HeLa cells to assess pendrin localization. Both mutations reduced membrane enrichment and increased intracellular retention. In vivo, compound heterozygous knock-in mouse models (Slc26a4c.574delC/c.919-2A>G and Slc26a4c.1211C>A/c.919-2A>G) were generated using CRISPR/Cas9. The auditory function and cochlear pathology were investigated. Both compound mutants exhibited elevated ABR thresholds, with more severe hearing loss in Slc26a4c.574delC/c.919-2A>G mice. Correspondingly, these mice showed marked hair cell disruption, stereociliary loss, and cochlear structural abnormalities, whereas the Slc26a4c.1211C>A/c.919-2A>G mice displayed milder changes. Transcriptomic profiling examined by bulk RNA-sequencing revealed broader differential expression in Slc26a4c.574delC/c.919-2A>G mice, enriched in structural and developmental pathways, while the missense model showed predominantly immune-related signatures. Our findings demonstrate that allele-specific functional divergence in compound heterozygous SLC26A4 mutations leads to distinct auditory dysfunction, cochlear pathology, and transcriptional programs. These findings provide mechanistic insight into the phenotypic heterogeneity of hearing loss and may indicate future allele-specific interventions or therapeutic strategies.

Oncomodulin (OCM) is the most abundant Ca2+ buffering protein found in mature outer hair cells (OHCs). Cadherin 23 (CDH23) is a crucial component of the tip-links in hair cell stereocilia. The absence or dysfunction of these two proteins contributes to the early onset of age-related hearing loss (AHL). In this study, we investigated the effects of the Cdh23753G→A mutation on OHC function using new Ocm-knockout (KO) mouse models (Ocmtm1a/tm1a) with or without the Cdh23753G→A mutation. Despite having the same genetic background, Ocm-KO mice carrying the Cdh23753G→A mutation displayed a notable decline in OHC function across all measured frequencies as early as three months of age. In contrast, Ocm-KO mice without the Cdh23753G→A mutation did not exhibit comparable hearing loss until they reached twelve months of age. Additionally, we examined the role of OCM in preserving OHC function under ototoxic stress induced by HPβCD (2-hydroxypropyl-β-cyclodextrin). The distortion product otoacoustic emission data show that the administration of HPβCD resulted in a more pronounced decline in OHC function in Ocm-KO mice compared to wild-type (WT) mice. Time-lapse recording also shows that HPβCD treatment led to greater structural deterioration and more rapid rupture events in OHCs from Ocm-KO mice than in those from WT mice. These findings suggest that the Cdh23753G→A mutation, rather than other potential strain-specific genetic factors associated with AHL, significantly exacerbates the early onset of AHL phenotypes in Ocm-KO mice. Furthermore, our data indicates that the OCM protein in OHCs enhances their ability to withstand ototoxic stimuli.

The CUGBP Elav-like family 4 (CELF4), an RNA-binding protein, is dynamically expressed in spiral ganglion neurons (SGNs) in the cochlea over development, but how Celf4 is involved in regulating hearing functions is poorly understood. In this study, we generated a Celf4 ± mouse line and examined changes in the first two synapses along the auditory pathways. Firstly, we found that hearing functions were largely intact in Celf4 ± mice, with exception of reduced amplitude for Wave II of auditory brainstem responses (ABRs) and increased delays for Wave II and IV, both in case of 4 kHz only. Secondly, we found that counts of inner and outer hair cells (IHCs and OHCs) and SGNs remained unchanged in Celf4 ± mice, and that the number and function of ribbon synapses between IHCs and SGNs were comparable between WT and Celf4 ± mice. Lastly, function of the endbulb of Held synapse, formed between auditory nerve fibers (ANFs) of SGNs and bushy cells in the cochlear nucleus, was significantly altered in Celf4 ± mice. Specifically, synaptic vesicle release was subtly reduced, and excitability of bushy cells was significantly dampened, likely due to a hyperpolarized resting membrane potential. Furthermore, we found that spike kinetics was significantly faster in Celf4 ± bushy cells, likely caused by a larger fast-inactivating A-type potassium current (I A ) found in these cells. In conclusion, we found that Celf4 haploinsufficiency altered transmission at the endbulb of Held synapses in the cochlear nucleus in a significant and multifaceted manner, revealing the roles of Celf4 in regulating hearing functions. Graphical Abstract Title: Schematic representation of the experimental approach and major findings. Legend: In mice with Celf4 haploinsufficiency, we found that while function at hair cell ribbon synapses was largely preserved, transmission at the endbulb of Held synapse was significantly altered, including subtly reduced release of synaptic vesicles from the endbulb, dampened excitability in bushy cells, and accelerated spike kinetics caused by enhanced voltage-gated K + current.

Activity-dependent modulation of presynaptic voltage-gated Ca 2+ channels (Ca V 2) regulates Ca 2+ influx to control neuronal circuit output. Although Ca V 2.1 can undergo robust Ca 2+ dependent facilitation (CDF), whether it occurs in native central nervous system neuronal circuits is disputed. Accurate auditory information processing requires precise and reliable synaptic transmission at high activity rates in the auditory brainstem. To determine if Ca V 2.1 CDF is a key regulator of high-fidelity synaptic transmission, we expressed Ca V 2.1 splice variants capable (Ca V 2.1 37a) or incapable (Ca V 2.1 37b) of CDF at the calyx of Held presynaptic terminal in the auditory brainstem. We found no difference in basal Ca V 2.1 currents or synaptic transmission. However, Ca V 2.1 37b terminals lacked CDF, synaptic facilitation and had a decreased reliability and precision of postsynaptic action-potential firing. Additionally, the Wave III amplitude of the auditory brainstem responses was reduced. We propose that Ca V 2.1 CDF is essential for accurate auditory information processing.

Sensorineural hearing loss (SNHL) induced by noise or aminoglycoside antibiotics is a significant public health concern without any FDA‐approved pharmaceutical therapies. Dysregulation of iron homeostasis and its subsequently induced ferroptosis has increasingly been identified as a key mechanism underlying cochlear hair cell (HC) damage. Nevertheless, the therapeutic targets for restoring iron balance for hearing protection remain poorly investigated. In this study, we uncover a previously unrecognized role of the SMO pathway in regulating iron homeostasis. SMO expression was rapidly upregulated and activated in HCs following injury. Both genetic ablation of Smo and pharmacological inhibition of SMO reduced iron accumulation and lipid peroxidation, promoting HC survival and preserving auditory function in mouse models of ototoxic‐ and noise‐induced hearing loss. Mechanistically, SMO inhibition suppressed ATF2 phosphorylation, resulting in downregulation of IRP1, which decreased iron accumulation via downregulation of Tfrc and upregulation of Fpn , ultimately protecting HCs from ferroptosis. Notably, treatment with the SMO inhibitor SANT‐1 nearly restored auditory thresholds to baseline levels in mice subjected to ototoxic injury. Our findings identify the SMO–ATF2–IRP1–FPN/TFRC axis as a central regulator of cochlear iron homeostasis and propose SMO inhibition as a promising therapeutic strategy for SNHL through precise modulation of iron metabolism.

Ménière's disease (MD), a chronic inflammatory disorder with age‐related increased incidence, exhibits poorly understood pathogenesis and limited therapeutic options. Here, we demonstrate that cellular senescence, marked by mitochondrial damage, reactive oxygen species accumulation, and senescence‐associated secretory phenotype (SASP), is prevalent in the vestibular tissue of MD patients and an endolymphatic hydrops mouse model. The transcription factor GATA4 is upregulated in MD and mice, and its genetic deletion in hair cells alleviates LPS‐induced audio‐vestibular dysfunction and cellular senescence in mice and HEI‐OC1 cells. Mechanistically, HDAC6 interacts with GATA4 and restrains its nuclear transport, while RNA‐seq and ChIP‐seq identify HtrA1, a serine protease, as a direct transcriptional target of GATA4. Inhibition of HDAC6 or AAV‐mediated HtrA1 overexpression exacerbates MD‐like symptoms, whereas inhibition of HtrA1 by Galegenimab ameliorates these phenotypes in mice. In aged mice, GATA4 deletion reduces age‐related audio‐vestibular deficits and senescence markers. Collectively, our findings establish GATA4 as a critical regulator of cellular senescence and inflammaging in inner ear pathologies, providing promising therapeutic targets for MD and age‐related audio‐vestibular disorders.

The molecular and cellular mechanisms underlying the function of the cochlear nucleus (CN) remain to be fully elucidated. Using single-nucleus RNA sequencing and single-cell spatial transcriptome analyses, we generated a comprehensive cell type atlas of the mouse CN, identified molecularly defined CN subregions, and quantified changes in gene expression and the spatial organization of CN cells in normal mice during postnatal development and in mutant mice with congenital hearing loss. We further identified a subtype of bushy cells expressing the osteopontin-encoding gene Spp1 as the primary CN cell type that exhibited hearing loss-induced alteration of gene expression. Among the highly affected genes in bushy cells, deletion of the auditory input-regulated gene Spp1 affected CN processing of auditory signals in mice. These results provide the most comprehensive cellular and molecular database to date for understanding auditory processing within the CN and identifying potential therapeutic targets for hearing restoration at the CN level.

Background: Kölliker’s organ (KO) support cells undergo orderly, time-dependent degeneration that is essential for auditory development and is accompanied by precisely regulated autophagic activity; however, the molecular hierarchy linking autophagy to this remodeling remains obscure. This study aimed to elucidate the regulatory mechanisms connecting autophagic flux to lysosomal biogenesis and auditory function during cochlear development. Method: We established an Atg5flox/flox; Sox2Cre+ mouse model with deletion of the autophagy gene Atg5 in cochlear-supporting cells. Auditory function was assessed via Auditory Brainstem Response (ABR) testing. Transcriptomic profiling of the neonatal basilar membrane was performed to screen for downstream targets. Mechanistic validation included spatiotemporal immunofluorescence mapping (E18–P30) and in vitro functional assays using siRNA-mediated knockdown and lysosomal tracking. Results: At 2 months of age, Atg5flox/flox; Sox2Cre+ mice exhibited moderate-to-severe sensorineural hearing loss accompanied by significant outer hair cell loss. Bulk RNA-seq of the basilar membrane identified fork-head box A3 (Foxa3) as a significantly downregulated transcription factor within the lysosomal–autophagy network. Spatiotemporal immunolabelling from embryonic day 18 to postnatal day 30 revealed that FOXA3 expression becomes progressively restricted to KO cells during postnatal development, with ATG5 loss reducing FOXA3 protein levels by 62.4%. In vitro, deficiency of either Atg5 or Foxa3 in primary KO cells resulted in comparable reductions in LAMP1-positive puncta. Conclusions: These findings support a model wherein the ATG5-FOXA3 axis contributes to lysosomal biogenesis in developing KO cells, with implications for understanding mechanisms of congenital sensorineural hearing loss.

Approximately 50% of hereditary deafness cases and most age-related hearing loss result from cochlear hair cell dysfunction. Adeno-associated virus (AAV)-mediated gene therapy offers a promising strategy for hearing restoration. However, the cochlea's complex cellular composition poses a significant challenge for targeted gene delivery into hair cells. Here, we establish a cross-species screening platform for cochlear AAV tools, applicable from rodents to large animals. Using this platform, we identify human promoters that specifically target inner hair cells, outer hair cells, or all hair cells in mice. The hair cell-specific coProB2 promoter is further validated in Bama miniature pigs and cynomolgus monkeys, achieving specific transgene expression in hair cells without auditory toxicity. Importantly, coProB2-driven gene therapies in DFNB79 and DFNB9 mouse models restore auditory function to near wild-type levels. Thus, this study establishes a cross-species-compatible, hair cell-specific AAV system, providing a versatile toolbox for cochlear hair cell gene therapy.

Background: Genetic diagnosis plays a critical role in enhancing the identification and clinical management of pediatric hearing loss, ultimately improving both physiological outcomes and social-emotional development. As one of the most prevalent sensory disorders characterized by substantial genetic heterogeneity, hearing loss requires the implementation of efficient diagnostic approaches to inform targeted clinical interventions and personalized care strategies. Methods: Here, we recruited 3353 Han Chinese children with nonsyndromic hearing loss, including 598 multiplex cases with family history. We employed SNPscan, targeted panel sequencing (TPS), and whole-exome sequencing (WES) to delineate the mutation landscape. Findings: Utilizing a tiered genomic testing strategy, we performed SNPscan for all 3353 participants, TPS for 675 cases, and WES for 204 multiplex cases. We achieved an overall diagnostic yield of 48.3% (1620/3353) in this cohort. Our analysis identified 87 previously unreported variants across 24 genes, including a de novo FOXI1 mutation (c.479_481del) linked to Mondini malformation and enlarged vestibular aqueduct, validated through knock-in mouse models. Additionally, we discovered NEU4 as a candidate gene related to hearing loss, with knockout mice and cellular models demonstrating its role in auditory dysfunction via disrupted neuraminidase activity and axonal development. These findings enrich the spectrum of deafness-related genes and provide a new theoretical foundation for diagnosing hearing loss. Interpretation: This study not only expands the genetic spectrum of hearing loss but also underscores the clinical utility of advanced sequencing in guiding precision therapies and early syndromic surveillance. This study offers a detailed characterization of the genetic landscape of pathogenic variants associated with hearing loss in the Han Chinese population, which will contribute to the design of a cost-effective genetic screening scheme, and also provides valuable insights that contribute to the global understanding of the genetics of hearing loss. Funding: This work was supported by the Key Program of National Natural Science Foundation of China, the National Key Research and Development Program of China, the National Natural Science Foundation of China and the Major Fundamental Research Program of the Natural Science Foundation of Shandong Province, China.

Noise exposures causing transient hearing loss were previously considered benign. However, recent work has revealed that temporary noise-induced threshold shifts may be associated with long-lasting cochlear histopathology. One such effect is cochlear synaptopathy, i.e. changes to the afferent synapse between inner hair cells and auditory nerve fibers. Noise-induced synaptopathy has been extensively characterized in several rodent models, and temporal bone studies suggest similar age-related changes in humans. However, it remains unclear how noise-induced temporary threshold shifts affect cochlear structures in humans and nonhuman primates, which show greater resistance to noise exposure than other animals. Additionally, the long-term sequelae of temporary threshold shifts are largely unknown. Here, we characterized the effects of a noise exposure causing temporary threshold shifts on cochlear histopathology in macaque monkeys at long post-exposure survival times. Overall, cochlear histopathology was variable across subjects, similar to the variable susceptibility observed in humans. At 2 and 10 months post-exposure, macaques had no significant loss of hair cells, inner hair cell synapses, or cholinergic efferent innervation. However, both inner and outer hair cell ribbons showed significant enlargement. Together, these findings provide insight into the cochlear effects of single-exposure temporary threshold shifts in nonhuman primates.

Age-related hearing loss (ARHL) is a rapidly growing public health concern, affecting two-thirds of adults over 65 years old, with no effective therapeutics available. As the aging population grows at an unprecedented rate, the burden of ARHL will only increase. The causes of ARHL are multifactorial, but an understudied major contributor is glial dysfunction. The auditory nerve (AN) conducts sound from the cochlea to the brainstem and holds a diverse population of immune cells and myelinating glia. As the AN fibers bundle together within the cochlea to project to the brainstem, they are first myelinated by Schwann cells in the peripheral AN, then myelinated by oligodendrocytes in the central AN. The region where myelination shifts from Schwann cells to oligodendrocytes is the glial transition zone (GTZ), located in the cochlear modiolus, creating a unique biological niche. While central-peripheral interfaces are recognized in other cranial nerves, the AN GTZ is understudied. This region integrates the peripheral and central microenvironments within the confined bony cochlea, positioning it as a niche for glial dysfunction in pathological conditions, such as aging. We hypothesize that the GTZ is a site of enhanced glial dysfunction contributing to age-related AN demyelination, an important contributor to ARHL. We evaluated this in an ARHL mouse model combining RNA-sequencing, quantitative immunohistochemistry, and 3D high-resolution imaging. We examined the AN GTZ from human temporal bone donors. RNA-sequencing of the AN revealed age-associated increases in abnormal myelination/glial function and inflammation. There was a significant age-dependent increase in Iba1 + macrophages/microglia, with accumulation at the AN GTZ, and an increase in cellular volume and surface area, suggesting greater age-related activation. Macrophages/microglia contained significantly more internalized myelin debris in the AN (peripheral, central, and GTZ) with aging. More importantly, we found structurally intact myelin within macrophages/microglia only at the GTZ, suggesting a unique microenvironment at the GTZ altering phagocytic activity in aging. Together, our data suggest that the GTZ, a previously unrecognized central-peripheral interface, is a critical site of immune-glial interactions and especially vulnerable to age-related demyelination and neuroinflammation. This study highlights the GTZ as a potential target for preserving AN myelination and mitigating ARHL.

Aminoglycoside antibiotics remain crucial for the treatment of severe infections caused by multidrug-resistant bacteria; however, their clinical use is limited by the risk of irreversible hearing loss. Previous studies have primarily attributed aminoglycoside-induced hearing loss to cochlear hair cell loss and subsequent spiral ganglion degeneration, while the contribution of the stria vascularis remains unclear. In the present study, we demonstrate that gentamicin administration induces apoptosis of stria vascularis pericytes, leading to stria vascularis dysfunction and consequent hearing loss in mice. Mechanistically, gentamicin exposure activated macrophages within the stria vascularis and significantly increased local expression of tumor necrosis factor-α (TNF-α). In vitro, we found that TNF-α triggered stria vascularis pericyte apoptosis via activation of the NF-κB signaling pathway. Importantly, in vivo pharmacological blockade of TNF-α with infliximab (IFX) or inhibition of NF-κB signaling with JSH-23 effectively preserved pericyte survival, attenuated stria vascularis damage, and mitigated gentamicin-induced hearing loss in mice. Collectively, these findings uncover TNF-α/NF-κB-dependent vascular-inflammatory mechanism underlying gentamicin ototoxicity and identify stria vascularis pericytes as a novel and druggable therapeutic target for the prevention of gentamicin-induced hearing loss.

Evolutionary shifts in diel activity patterns shape sensory remodeling across mammals, yet the genetic basis remains poorly understood. Tapirs represent a unique natural experiment, having reverted from a cathemeral ancestor to a nocturnal niche characterized by reduced vision but enhanced hearing and olfaction. Here, we investigate the genetic basis of this phenomenon by generating high-quality chromosome-level genomes for Tapirus terrestris and Tapirus indicus . Comparative analyses revealed extensive lineage-specific remodeling of genes and cis-regulatory elements linked to sensory pathways. Notably, functional validation via CRISPR-Cas9 editing of a tapir-specific conserved noncoding element (CNE74) upstream of the FLT1 gene in mice revealed coordinated sensory effects, including retinal degeneration and reduced visual acuity, yet enhanced auditory sensitivity. These findings suggest that regulatory element evolution may induce pleiotropic effects on competing sensory modalities, offering genetic insights into sensory evolution during temporal niche adaptation and potential relevance to human retinal vascular diseases.