New mouse models for inducible cell-specific ablation

 描述(由申请人提供)：感音神经性听力损失(SNHL)是一个严重的医疗问题，具有巨大的社会和经济成本。当内耳的听觉感觉毛细胞或连接这些细胞和大脑的主要神经通路停止正常功能时，SNHL就会发生。这种损害是由于遗传和/或环境侮辱而发生的。SNHL是永久性的，因为随后的感觉和/或神经细胞死亡，以及这些细胞不能再生。关于如何促进哺乳动物中丢失的听觉毛细胞和神经元的再生，有很多想法。这些措施包括刺激残留的内源性支持细胞再生毛细胞，这在鱼类和鸟类中是常见的。类似地，螺旋神经节神经元可能是由胶质细胞再生的。在这两种情况下，对通常参与这些细胞发育的信号和转录因子的操纵正在进行深入的研究。基于干细胞的替代策略也在进行中。不管首选的方法是什么，任何治疗SNHL的建议都需要在活体哺乳动物模型中进行测试。然而，现有的哺乳动物外周听觉系统感觉和神经细胞丢失的模型并不理想。例如，耳毒性药物和噪声暴露都可以暂时控制以导致听力损失，但这些治疗影响整个内耳，不仅影响听觉毛细胞和/或螺旋神经节神经元，这可能会扰乱治疗研究。基于可诱导的单重组酶的方法去除内耳感觉或神经细胞是很有前途的，但也经常影响动物生存所必需的其他细胞/组织，从而限制了它们的应用。在这一应用中，我们建议开发和验证一种改进的系统，称为交叉和诱导细胞特异性消融(IICSA)，用于在感兴趣的任何阶段诱导精确和可重复的消融小鼠听觉毛细胞或螺旋神经节神经元。这将使不同阶段的内毛细胞、外毛细胞或螺旋神经节神经元丢失的建模成为可能，并为测试哺乳动物的听力恢复疗法提供一个平台。IICSA是当前技术的一项重大进步，因为它将使多西环素诱导的细胞消融具有减少或消除脱靶效应的可能性。我们将使用最先进的定向转基因和基因组编辑技术来产生必要的IICSA驱动和效应型小鼠品系。这项技术将被开发和测试用于特定类型的耳蜗细胞的诱导性消融，但可以适应任何感兴趣的目标细胞，从而能够为基础和翻译研究建立任意数量的退化条件的模型。

 DESCRIPTION (provided by applicant): Sensorineural hearing loss (SNHL) is a significant healthcare problem, with large social and financial costs. SNHL occurs when the auditory sensory hair cells of the inner ear, or the primary neural pathways connecting these cells to the brain, cease to function appropriately. Such damage occurs consequent to genetic and/or environmental insults. SNHL is permanent because of subsequent sensory and/or neural cell death, and the inability of such cells to regenerate. There are many ideas about how to provoke regeneration of lost auditory hair cells and neurons in mammals. These include stimulating regeneration of hair cells from residual endogenous supporting cells, as occurs normally in fish and birds. Similarly, spiral ganglion neurons might be regenerated from glia. In both cases, manipulating the signals and transcription factors normally involved in the development of these cells is under intensive investigation. Stem cell-based replacement strategies are also being pursued. Regardless of the preferred approach, any proposed therapy for SNHL will require testing in an in vivo mammalian model. However, existing mammalian models of sensory and neural cell loss in the peripheral auditory system are not ideal. For example, both ototoxic drugs and noise exposure can be controlled temporally to cause hearing loss, but these treatments affect the entire inner ear, not only the auditory hair cells and/or spiral ganglion neurons, and this can confound treatment studies. Inducible single recombinase-based methods of ablating inner ear sensory or neural cells are promising, but also frequently impact other cells/tissues that are essential for viability of the animal, thus limiting their utility. In this application, w propose to develop and validate an improved system, called intersectional and inducible cell-specific ablation (IICSA), for inducing precise and reproducible ablation of mouse auditory hair cells or spiral ganglion neurons at any stage of interest. This will enable modeling of inner hair cell, outer hair cell or spiral ganglion neuron loss at different stages, and provide a platform fo testing hearing restoration therapies in a mammal. IICSA is a significant advance over current technology because it will enable doxycycline-inducible cell ablation with the potential for reduced or absent off-target effects. We will use state- of-the-art targeted transgenesis and genome editing techniques to generate the necessary IICSA driver and effector mouse strains. This technology will be developed and tested for inducible ablation of specific cochlear cell types, but is adaptable to any target cells of interest, enabling modeling of any number of degenerative conditions for both basic and translational studies.