Tetsuji Yamashita

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Outer hair cells (OHCs) in the cochlea are crucial for the remarkable hearing sensitivity and frequency tuning. To understand OHC physiology and pathology, it is imperative to use mouse genetic tools to manipulate gene expression specifically in OHCs. Here, we generated two prestin knockin mouse lines: (1) the prestin-CreERT2 line, with an internal ribosome(More)
The remarkable hearing sensitivity and frequency selectivity in mammals is attributed to cochlear amplifier in the outer hair cells (OHCs). Prestin, a membrane protein in the lateral wall of OHC plasma membrane, is required for OHC electromotility and cochlear amplifier. In addition, GLUT5, a fructose transporter, is reported to be abundant in the plasma(More)
The mammalian outer hair cells (OHCs) provide a positive mechanical feedback to enhance the cochlea's hearing sensitivity and frequency selectivity. Although the OHC-specific, somatic motor protein prestin is required for cochlear amplification, it remains unclear whether prestin can provide sufficient cycle-by-cycle feedback. In cochlear mechanical(More)
In biology, redox reactions are essential and sometimes harmful, and therefore, iron metabolism is tightly regulated by cuproproteins. Since the state of copper in iron overload syndromes remains unclear, we investigated whether copper metabolism is altered in these syndromes. Eleven patients with iron overload syndromes participated in this study. The(More)
Studies of hair cell regeneration in the postnatal cochlea rely on fate mapping of supporting cells. Here we characterized a Sox2-CreER knock-in mouse line with two independent reporter mouse strains at neonatal and mature ages. Regardless of induction age, reporter expression was robust, with CreER activity being readily detectable in >85% of supporting(More)
Interleukin-1 (IL-1) mediates diverse neurophysiological and neuropathological effects in the CNS through type I IL-1 receptor (IL-1R1). However, identification of IL-1R1-expressing cell types and cell-type-specific functions of IL-1R1 remains challenging. In this study, we created a novel genetic mouse model in which IL-1R1 gene expression is disrupted by(More)
Nature's fastest motors are the cochlear outer hair cells (OHCs). These sensory cells use a membrane protein, Slc26a5 (prestin), to generate mechanical force at high frequencies, which is essential for explaining the exquisite hearing sensitivity of mammalian ears. Previous studies suggest that Slc26a5 continuously diffuses within the membrane, but how can(More)
Hearing loss is widespread and persistent because mature mammalian auditory hair cells (HCs) are nonregenerative. In mice, the ability to regenerate HCs from surrounding supporting cells (SCs) declines abruptly after postnatal maturation. We find that combining p27Kip1 deletion with ectopic ATOH1 expression surmounts this age-related decline, leading to(More)
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