MOLECULAR CHARACTERIZATION OF NON-MYELINATING SCHWANN CELLS

描述（由申请人提供）：获得性周围神经病变通常由糖尿病、化疗和HIV/AIDS引起，因此对社会造成了相当大的且日益增加的医疗保健负担。神经病的有效治疗需要了解周围神经中神经胶质和轴突之间的相互作用。有髓鞘的许旺细胞已被广泛研究，但对无髓鞘的许旺细胞知之甚少。由于它们与传递疼痛的无髓鞘感觉纤维有关，因此它们可能参与与糖尿病和其他小纤维神经病相关的病理学过程。此外，对细胞代谢重要的基因中的Schwann细胞特异性突变强烈影响无髓鞘轴突稳定性，揭示了这些细胞与周围神经疾病之间重要但很少探索的联系。因此，了解非髓鞘化雪旺细胞的生物学是开发周围神经疾病新疗法的重要途径。我们已经开发了几种独立的方法来获得非髓鞘形成的雪旺细胞的基因表达谱，以确定这些细胞的新标记物，并确定其在疾病，特别是代谢性疾病中的功能障碍影响外周神经功能的机制。此外，我们已经产生了转基因小鼠，表达两种蛋白质，eGFP标记的核糖体蛋白，和他莫昔芬诱导的Cre重组酶，在非髓鞘形成的雪旺细胞。标记的核糖体蛋白将允许通过翻译核糖体亲和纯化（TRAP）（一种用于确定特定细胞类型的基因表达谱的强大方法）在非髓鞘形成的许旺细胞中分离和分析多核糖体相关mRNA。Cre重组酶将使我们能够特异性地操纵非髓鞘形成的许旺细胞中的基因表达，或者完全消除它们。这样的实验是必要的解剖非髓鞘形成的雪旺细胞和它们相关的轴突之间的复杂的相互作用。这些新的转基因小鼠系将允许我们在遗传或环境干扰后以及在遗传性或获得性PNS疾病模型中建立非髓鞘化雪旺细胞的基因表达特征。特别是，我们将使用这些方法来研究代谢缺陷如何导致无髓鞘轴突丢失和神经病变的分子方面。通过识别和操纵健康和疾病中非髓鞘化雪旺细胞中改变的基因，我们希望获得对潜在病理学的新见解，并开辟治疗周围神经病的新途径。

DESCRIPTION (provided by applicant): Acquired peripheral neuropathy commonly results from diabetes, chemotherapy and HIV/AIDS, and therefore imposes a considerable, and increasing, health care burden on society. Effective treatment of neuropathy requires an understanding of the interactions between glia and axons in the peripheral nerve. Myelinating Schwann cells have been studied extensively, but less is known about non-myelinating Schwann cells. Because they are associated with unmyelinated sensory fibers that transmit pain, they are likely to participate in the pathology associated with diabetic and other small-fibe neuropathies. Furthermore, Schwann cell-specific mutations in genes that are important for cellular metabolism strongly affect unmyelinated axon stability, revealing an important but little explored link between these cells and peripheral nerve disease. Therefore an understanding of the biology of non-myelinating Schwann cells is an important approach toward developing new treatments for peripheral nerve diseases. We have developed several independent approaches for obtaining gene expression profiles of non-myelinating Schwann cells in order to identify new markers for these cells, and to identify mechanisms whereby their functional impairment in disease, particularly metabolic disease, affects peripheral nerve function. In addition, we have generated transgenic mice that express two proteins, an eGFP-tagged ribosomal protein, and tamoxifen-inducible Cre recombinase, in non-myelinating Schwann cells. The tagged ribosomal protein will permit the isolation and profiling of polyribosome-associated mRNAs in non-myelinating Schwann cells by translating ribosome affinity purification, or TRAP, a powerful method for determining gene expression profiles of specific cell types. The Cre recombinase will permit us to specifically manipulate gene expression in non-myelinating Schwann cells, or ablate them entirely. Such experiments are necessary to dissect the complex interactions between non-myelinating Schwann cells and their associated axons. These new transgenic mouse lines will permit us to establish gene expression signatures of non-myelinating Schwann cells after genetic or environmental perturbation and in models of inherited or acquired PNS disease. In particular we will use these methods to investigate the molecular aspects of how metabolic deficits lead to unmyelinated axon loss and neuropathy. Through the identification and manipulation of genes altered in non-myelinating Schwann cells in health and disease, we hope to gain new insights into the underlying pathology and open up new avenues for treatment of peripheral neuropathies.