Cellular therapy for the inner ear

内耳细胞疗法

基本信息

批准号：
8984514
负责人：
Albert Edge
金额：
$ 49.24万
依托单位：
MASSACHUSETTS EYE AND EAR INFIRMARY
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-08-12 至 2018-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8984514
关键词：
Acoustic Nerve Acoustics Action Potentials Adult Afferent Neurons Animals Auditory Auditory Brainstem Responses Auditory system Behavior assessment Behavioral Bilateral Biological Models Biological Preservation Brain CNS processing Cell Death Cell Therapy Cells Chemicals Cochlea Complex Denervation Detection Discrimination Doxycycline Ear Excision Functional disorder Genes Genetic Glutamates Goals Grant Hair Cells Hearing Immunohistochemistry In Situ In Vitro Inferior Colliculus Labyrinth Lead Measurement Measures Midbrain structure Modeling Morphology Mus Natural regeneration Nerve Nerve Degeneration Nerve Regeneration Nervous system structure Neuronal Differentiation Neurons Noise Organ of Corti Ouabain Outer Hair Cells Perception Peripheral Process Reading Recovery Recovery of Function Role Route Schwann Cells Sensorineural Hearing Loss Signal Transduction Small Interfering RNA Stem cell transplant Stem cells Stimulus Synapses System Testing Therapeutic Time Tissues Toxic effect Up-Regulation Work axon growth axonal guidance base behavior measurement behavior test deafness embryonic stem cell ganglion cell hearing impairment improved in vivo in vivo Model inhibitor/antagonist kainate mouse model neogenin nerve stem cell nerve supply neural circuit neurogenesis neuron loss neurotrophic factor novel novel strategies otoacoustic emission patch clamp postsynaptic progenitor promoter public health relevance receptor reconstitution reinnervation relating to nervous system repaired research study response restoration sound spiral ganglion success synaptic function synaptogenesis transdifferentiation

项目摘要

DESCRIPTION (provided by applicant): Degeneration of neural circuitry, either through synaptic loss or neural cell death, is an important cause of nervous system dysfunction, and afferent auditory nerve loss leading to deafness is a manifestation of these processes occurring in the cochlea. Our previous work has shown that neurons from transplanted stem cells can reinnervate hair cells of the organ of Corti after chemical de-afferentation, suggesting that this neural circuit can be reconstituted. In these studies we ask questions about repair of both types of neural degeneration: first, we investigate whether reinnervation and synaptogenesis with hair cells can be increased by manipulating axonal guidance and neurotrophic factors in in vitro and in vivo models of synapse damage; second, we study the effect of progenitor cell transdifferentiation to neurons and the regeneration of this circuit in a model of complete afferent neuron loss. Measurements of synaptic and neural repair include electrophysiological and histological analysis of new synapses in vitro and immunohistochemical as well as peripheral, central, and behavioral assessments of auditory function in vivo. Understanding the mechanisms underlying re-formation of neural connections to hair cells in the adult ear is important to therapeutic approaches for the treatment of neural dysfunction that causes hearing loss. The Specific Aims comprise three inter-related experiments to probe key variables likely to influence the success of peripheral and central reinnervation of the auditory system. In Aim 1 we assess the effect of inhibitors of axonal guidance as well as promoters of axonal growth on the reinnervation of hair cells in cochlear models with loss of the afferent synapse but preservation of ganglion cells. In the in vitro system (afferent synapses lost due to kainate administration) we use electrophysiological measurements to assess synaptic function: firing of action potentials and excitatory postsynaptic currents by the neurons after stimulation of hair cells, and inhibition of this synaptic function by pharmacological blockers of glutamatergic synapses. In the in vivo system (noise damage causing afferent synapse loss) metrics include synaptic analysis as well as auditory brainstem response and distortion product otoacoustic emissions. Assessments are based on the morphology and number of synapses formed with inner and outer hair cells determined immunohistochemically. In Aim 2 we define the roles and optimal expression levels of Sox2 as well as Ngn1 for Schwann cell to neuronal conversion. We have isolated progenitor cells that can be converted to neurons from spiral ganglion, and we have shown that these cells arise from Schwann cells. We test the role of Sox2 and Ngn1 in this conversion. We assess conversion of Schwann cells to neurons in vivo using ouabain to produce a model of auditory nerve damage, and we stimulate the conversion of endogenous cells to spiral ganglion cells by modulating expression of the same genes. In Aim 3 we record the spiking activity from single neurons in the auditory midbrain to sound stimuli delivered to the reinnervated and untreated ears. We compare markers of neural recovery to behavioral measures of improved sound discrimination.

描述（通过应用程序提供）：神经元回路的变性是通过合成损失或神经元细胞死亡的变性，是神经系统功能障碍的重要原因，传入的听觉神经损失导致死亡的表现是这些过程的表现。我们以前的工作表明，移植的干细胞的神经元可以在化学去屈服后重新染色皮尔蒂的毛细胞，这表明可以重构该神经元回路。在这些研究中，我们询问有关两种神经元变性修复的问题：首先，我们研究是否可以通过操纵体外和体内突触损害模型中的轴突引导和神经营养因子来增加毛细胞的重新支配和突触形成；其次，我们研究了祖细胞细胞转分解向神经元的影响，并在完全传入的神经元丧失模型中研究了该回路的再生。突触和神经修复的测量包括对体外和免疫组织化学新突触的电生理学和组织学分析，以及外周，中央和行为评估的体内功能。了解神经元连接到成年耳朵中毛细胞的基础机制对于治疗导致听力损失的神经元功能障碍的治疗方法很重要。该特定目的包括三个相互关联的实验，以探测可能影响听觉系统周围和中央重新支配成功的成功变量。在AIM 1中，我们评估了轴突引导抑制剂以及轴突生长的启动子对人工耳蜗模型中毛细胞的重新连接的启动子，而传入突触的丧失，但保留了神经节细胞。在体外系统中（由于给药而导致的传入突触）我们使用电生理测量来评估突触功能：刺激毛细胞后神经元的动作电位和兴奋后的突触电流发射，并抑制谷氨酸能突触的药物阻滞剂的合成功能。在体内系统（导致传入突触损失的噪声损害）中，指标包括合成分析以及听觉的脑干响应和失真产物耳声排放。评估基于由内部和外毛细胞形成的突触的形态和数量，以免疫组织化学确定。在AIM 2中，我们定义Sox2的作用和最佳表达水平以及Schwann细胞到神经元转化的NGN1。我们有分离的祖细胞，可以从螺旋神经节转化为神经元，并且已经表明这些细胞来自雪旺氏细胞。我们测试了Sox2和Ngn1在此转换中的作用。我们使用ouabain评估雪旺细胞在体内转化为神经元，以产生听觉神经损伤模型，并通过调节相同基因的表达来刺激内源性细胞向螺旋神经节细胞的转化。在AIM 3中，我们记录了来自听觉中脑中单个神经元的尖峰活动，到传递到重新染色和未经处理的耳朵的声音兴奋剂。我们将神经记录的标记与改善声音歧视的行为度量进行比较。