Wnt pathway mutations alter hair cell regeneration in the zebrafish fish lateral line

摘要 使人衰弱的听力损失影响着世界上6%以上的人口，并可能导致严重的听力损失。 降低患者的生活质量。听觉是由机械感觉毛发介导的 位于内耳耳蜗中的细胞。内耳中的另一群毛细胞 组成前庭系统来传递平衡和重力的感觉。毛细胞损伤 导致感官缺陷。毛细胞损伤的原因包括年龄、噪声暴露、耳毒性 药物、疾病和伤害。在成年哺乳动物中，一旦毛细胞丢失，它们就不会再生， 导致永久性听力损失和平衡障碍。 除了介导听觉和平衡感，机械感觉毛细胞还 在水生脊椎动物的侧线系统中也需要近距离接触感觉。横向 线毛细胞在形态上和遗传上与内耳毛细胞非常相似。相比之下 对于哺乳动物的内耳毛细胞，侧线系统的毛细胞是健壮的， 再生的斑马鱼（Danio rerio）已成为研究 机械感觉毛细胞再生的机制。 使用经典Wnt通路的药理学操作的研究表明， 对于调节毛细胞所需的细胞增殖和分化至关重要 再生为了从遗传学上证实Wnt信号在再生过程中的作用，我们将使用 在Wnt途径的不同点携带突变的三个斑马鱼系。在目标1中，我们 表征krm1nl10突变体中的毛细胞再生，其导致Wnt过度活化 信号在目的2中，我们将表征lef1nl2突变系中的再生，这导致 抑制Wnt活性。在目标3中，我们将研究第三个品系foxg1aa266的再生， 其包含Wnt转录靶基因foxg1a中的突变。我们将共同利用 这些细胞系，以确定细胞增殖，分化和生存是如何调节， 机械感觉毛细胞再生过程中的Wnt通路。长期目标是 这项工作的目的是提供一种机制，使人类内耳的毛细胞再生。

Abstract Debilitating hear loss affects over 6% of the world’s population and can result in a profound decrease in the quality of life for those afflicted. Hearing is mediated by mechanosensory hair cells located in the cochlea of the inner ear. Another population of hair cells in the inner ear makes up the vestibular system to relay the sensation of balance and gravity. Hair cell damage results in sensory defects. The causes of hair cell damage include age, noise exposure, ototoxic drugs, disease, and injury. In adult mammals, once hair cells are lost, they do not regenerate, resulting in permanent hearing loss and balance disorders. In addition to mediating the sensations of hearing and balance, mechanosensory hair cells are also required for close touch sensation in the lateral line systems of aquatic vertebrates. Lateral line hair cells are morphologically and genetically very similar to inner ear hair cells. In contrast to the inner ear hair cell of mammals, the hair cells of the lateral line system are robustly regenerative. The zebrafish (Danio rerio), has emerged as a valuable model to study the mechanisms of mechanosensory hair cell regeneration. Research using pharmacological manipulation of the canonical Wnt pathway suggests that it is critical for regulating the cellular proliferation and differentiation required for hair cell regeneration. To genetically confirm a role for Wnt signaling during regeneration, we will use three zebrafish lines carrying mutations at different points in the Wnt pathway. In Aim 1, we will characterize hair cell regeneration in the krm1nl10 mutant, which results in overactivation of Wnt signaling. In Aim 2, we will characterize regeneration in the lef1nl2 mutant line, which results in an inhibition of Wnt activity. In Aim 3, we will examine regeneration in a third line, foxg1aa266, which contains a mutation in the Wnt transcriptional target gene foxg1a. Together, we will use these lines to determine how cellular proliferation, differentiation, and survival are regulated by the Wnt pathway during regeneration of mechanosensory hair cells. The long-term goal of this work is to provide a mechanism for regenerate hair cells in the human inner ear.