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Sensory hair bundles in the inner ear are composed of stereocilia that can be interconnected by a variety of different link types, including tip links, horizontal top connectors, shaft connectors, and ankle links. The ankle link antigen is an epitope specifically associated with ankle links and the calycal processes of photoreceptors in chicks. Mass spectrometry and immunoblotting were used to identify this antigen as the avian ortholog of the very large G-protein-coupled receptor VLGR1, the product of the Usher syndrome USH2C (Mass1) locus. Like ankle links, Vlgr1 is expressed transiently around the base of developing hair bundles in mice. Ankle links fail to form in the cochleae of mice carrying a targeted mutation in Vlgr1 (Vlgr1/del7TM), and the bundles become disorganized just after birth. FM1-43 [N-(3-triethylammonium)propyl)-4-(4-(dibutylamino)styryl) pyridinium dibromide] dye loading and whole-cell recordings indicate mechanotransduction is impaired in cochlear, but not vestibular, hair cells of early postnatal Vlgr1/del7TM mutant mice. Auditory brainstem recordings and distortion product measurements indicate that these mice are severely deaf by the third week of life. Hair cells from the basal half of the cochlea are lost in 2-month-old Vlgr1/del7TM mice, and retinal function is mildly abnormal in aged mutants. Our results indicate that Vlgr1 is required for formation of the ankle link complex and the normal development of cochlear hair bundles.
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http://dx.doi.org/10.1523/JNEUROSCI.0693-06.2006 | DOI Listing |
Adv Sci (Weinh)
September 2025
Department of Otolaryngology-Head and Neck Surgery, Stanford University, Palo Alto, 94304, USA.
The plasma membrane is actively regulated by lipid transporters that create electrochemical gradients between leaflets, and passively by scramblases that dissipate these gradients. Membrane properties such as lipid packing are critical for the proper function of transmembrane proteins, particularly mechanosensitive ion channels. Mechanosensation is a key component of many sensory processes including balance, and hearing.
View Article and Find Full Text PDFNeurobiol Aging
August 2025
Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki 00010, Finland. Electronic address:
Hallmarks of sensorineural hearing loss are elevated hearing thresholds and defects in temporal auditory processing, the former being often caused by outer hair cell (OHC) damage, and the latter by the loss of synapses between inner hair cells (IHCs) and spiral ganglion neurons. In the well-studied CBA/CaJ mouse strain, these impairments are disconnected, IHC synaptopathy preceding OHC loss. We have investigated the relationship between IHC synaptopathy and OHC loss in the C57BL/6J (B6) and ICR mouse strains that model accelerated age-related hearing loss.
View Article and Find Full Text PDFNeurosci Bull
August 2025
ENT Institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China.
Vestibular hair cells (HCs) in the inner ear, crucial for balance and spatial orientation, are classified into type I and type II subtypes, but the mechanisms regulating their differentiation remain unclear. In this study, we examined the role of Pou4f3, an important transcription factor, in vestibular HC differentiation using Pou4f3 (deficient) and Pou4f3 (knockout) mouse models. In Pou4f3-deficient mice, the HC number decreased, and immature HCs failed to develop type I characteristics, indicating a developmental arrest.
View Article and Find Full Text PDFmedRxiv
August 2025
Mass Eye and Ear, Eaton Peabody Laboratories, Boston, MA, 02114, USA.
Identifying new genes responsible for non-syndromic hearing loss remains a critical goal, as many individuals with hereditary deafness still lack a molecular diagnosis despite comprehensive genetic testing. The tectorial membrane (TM) is a specialized, collagen-rich, acellular matrix of the inner ear, essential for stimulating mechanosensitive hair cell bundles during sound transduction, and its structural integrity is critical for frequency tuning and auditory sensitivity. Although mutations in genes encoding a number of non-collagenous proteins found in the TM (TECTA, CEACAM16, OTOG, OTOGL) have been identified as deafness genes, definitive evidence implicating β-tectorin (TECTB) in human hearing loss has been lacking.
View Article and Find Full Text PDFDis Model Mech
August 2025
Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD 21201, USA.
Methionine sulfoxide reductases (MSRs) are enzymes responsible for catalyzing the reduction of methionine sulfoxides. We previously demonstrated that variants in human MSRB3, an MSR family member, are associated with profound autosomal recessive prelingual non-syndromic deafness, DFNB74. To better understand the role of MSRB3 in the auditory pathway, we generated complete Msrb3 gene knockout mice.
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