Motor Neuron Regeneration Model on ALS-Like Mouse Lifes*

运动神经元功能丧失会导致寿命缩短：1)。选择性抑制运动神经元规范基因(Hb或Nkx6.1)的表达会导致基因敲除小鼠早期发育阶段的死亡；在转基因小鼠(大鼠)模型中，通过过度表达突变的SOD1基因选择性地变性成熟的运动神经元，导致模拟人类肌萎缩侧索硬化症(ALS)的运动功能丧失。本研究的长期目标是在类ALS转基因小鼠模型中研究HB-9表达在运动神经元再生和延长寿命中的作用。 目前研究方案的假设是，在小鼠模型中，HB-9基因的诱导可能会诱导运动神经元从神经前体细胞(干细胞)体内分化。新再生的运动神经元可能在功能上替代变性的运动神经元，从而可能延长ALS类转基因小鼠的寿命。为了检验这一假设，将执行以下具体目标： 特定目的1：建立诱导HB-9在神经细胞表达的转基因小鼠模型 前体细胞。具体地说，我们将使用成熟的Tet-on/tre系统来确定Lib-9在同时含有pNestinrtTA和tre-HB-9转基因双转基因小鼠的神经前体细胞中表达的诱导条件。 具体目的2：确定HB-9在神经前体细胞中的表达是否能促进运动神经元的分化和再生。具体地说，我们将使用特定的运动神经元标记来分析HB-9介导的运动神经元在Dox诱导的双转基因小鼠脊髓中的指定和分化(再生)。 未来的研究方向将集中在运动神经元的三转基因小鼠模型上。 肌萎缩侧索硬化症转基因小鼠系统中改善运动功能和延长寿命的规范和再生。

Loss of motor neuron function causes reduction of lifespan: 1). Selective inhibition of motor neuron specification gene (HB or Nkx6.1) expression results in lethality at early developmental stages in the knockout mouse models; 2). Selective degeneration of matured motor neurons by overexpression of mutant SOD1 gene in the transgenic mouse (rat) models causes loss of motor function mimicking human amyotrophic lateral sclerosis (ALS). The long-term objective of this research application is to study the role of HB-9 expression in motor neuron regeneration and in extension of lifespan in the ALS-like transgenic mouse model. The hypothesis of the current research proposal is that the induction of HB-9 gene expression may induce motor neuron specification from neural precursor (stem) cells in vivo in a mouse model. The newly regenerated motor neurons may functionally replace the degenerated motor neurons and therefore may extend the lifespan of ALS-like transgenic mice. The following specific aims will be performed to test the hypothesis: Specific Aim 1: To generate transgenic mouse model for induction of HB-9 expression in neural precursor cells. Specifically, we will use the well-established Tet-on/TRE systems to define the induction conditions for expression of liB-9 in neural precursor cells of the bi-transgenic mice containing both pNestinrtTA and TRE-HB-9 transgenes. Specific Aim 2: To determine if the expression of HB-9 in neural precursor cells can promote motor neuron specification and regeneration. Specifically, we will use specific motor neuron markers to analyze HB-9-mediated motor neuron specification and differentiation (regeneration) in the bi-transgenic mouse spinal cord induced by Dox. The future research directions will focus on the tri-transgenic mouse model of motor neuron specification and regeneration on the improvement of motor function and the extension of lifespan in the ALS-like transgenic mouse system.