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）是一个重大的医疗保健问题，具有巨大的社会和经济成本。当内耳的听觉感觉毛细胞或将这些细胞连接到大脑的主要神经通路停止正常工作时，就会发生SNHL。这种损害是遗传和/或环境损害的结果。SNHL是永久性的，因为随后的感觉和/或神经细胞死亡，以及这些细胞无法再生。关于如何刺激哺乳动物失去的听觉毛细胞和神经元再生，有很多想法。这些包括刺激毛细胞从残留的内源性支持细胞再生，就像鱼类和鸟类通常发生的那样。同样，螺旋神经节神经元也可以从胶质细胞再生。在这两种情况下，操纵通常参与这些细胞发育的信号和转录因子正在深入研究中。基于干细胞的替代战略也在推行中。无论首选的方法如何，任何提出的SNHL疗法都需要在体内哺乳动物模型中进行测试。然而，现有的哺乳动物模型的感觉和神经细胞损失的外周听觉系统是不理想的。例如，耳毒性药物和噪声暴露都可以暂时控制以引起听力损失，但这些治疗影响整个内耳，而不仅仅是听觉毛细胞和/或螺旋神经节神经元，这可能会混淆治疗研究。消融内耳感觉或神经细胞的基于诱导性单重组酶的方法是有希望的，但也经常影响对动物的生存力至关重要的其他细胞/组织，从而限制了它们的实用性。在本申请中，我们提出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），用于在任何感兴趣的阶段诱导小鼠听觉毛细胞或螺旋神经节神经元的精确和可重复的消融。这将使得能够在不同阶段对内毛细胞、外毛细胞或螺旋神经节神经元损失进行建模，并提供用于在哺乳动物中测试听力恢复疗法的平台。IICSA是当前技术的一个重大进步，因为它将使多西环素诱导的细胞消融具有减少或不存在脱靶效应的潜力。我们将使用最先进的靶向转基因和基因组编辑技术来产生必要的IICSA驱动和效应小鼠品系。该技术将被开发和测试用于特定耳蜗细胞类型的诱导性消融，但适用于任何感兴趣的靶细胞，从而能够为基础和转化研究建模任何数量的退行性疾病。

 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.