National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA.
Qiagen Sciences Inc., Germantown, MD, 20874, USA.
Nat Commun. 2020 Jan 2;11(1):63. doi: 10.1038/s41467-019-13710-4.
Each vestibular sensory epithelium in the inner ear is divided morphologically and physiologically into two zones, called the striola and extrastriola in otolith organ maculae, and the central and peripheral zones in semicircular canal cristae. We found that formation of striolar/central zones during embryogenesis requires Cytochrome P450 26b1 (Cyp26b1)-mediated degradation of retinoic acid (RA). In Cyp26b1 conditional knockout mice, formation of striolar/central zones is compromised, such that they resemble extrastriolar/peripheral zones in multiple features. Mutants have deficient vestibular evoked potential (VsEP) responses to jerk stimuli, head tremor and deficits in balance beam tests that are consistent with abnormal vestibular input, but normal vestibulo-ocular reflexes and apparently normal motor performance during swimming. Thus, degradation of RA during embryogenesis is required for formation of highly specialized regions of the vestibular sensory epithelia with specific functions in detecting head motions.
内耳中的每个前庭感觉上皮在形态和生理上可分为两个区域，在耳石器官的耳石斑中称为条纹区和条纹外区，在半规管嵴中称为中央区和周边区。我们发现，胚胎发生过程中条纹区/中央区的形成需要细胞色素 P450 26b1（Cyp26b1）介导的视黄酸（RA）降解。在 Cyp26b1 条件性敲除小鼠中，条纹区/中央区的形成受到损害，使得它们在多个特征上类似于条纹外区/周边区。突变体对急动刺激、头部震颤的前庭诱发电位（VsEP）反应以及在平衡木测试中的缺陷，与异常的前庭输入一致，但前庭眼反射正常，游泳时的运动表现显然正常。因此，胚胎发生过程中 RA 的降解对于形成具有特定功能的前庭感觉上皮的高度特化区域是必需的，这些区域在检测头部运动方面具有特异性。
