Discover the signaling basis for OPC homeostasis

在这项提案中，我们将解决神经胶质生物学中一个根本性的重要问题：少突胶质细胞如何 前体细胞（OPCs）是否能保持其数量？先前的活体成像实验表明， OPCs相互接触时相互抑制，但相邻时迅速进入细胞周期， OPCs要么分化要么死亡，当达到稳态时再次停止增殖。但 OPC稳态背后的分子基础仍然是未知的。最近，利用老鼠遗传系统， 我们的实验室用称为双标记镶嵌分析（MADM）的方法来模拟胶质瘤，发现OPC是一种 神经胶质瘤的起源，并揭示，而不是被动过度扩张，突变的OPCs实际上胜过 WT OPCs并最终接管整个大脑。最重要的是，当我们从基因上阻断细胞 突变OPCs的竞争，胶质瘤可以完全预防。将OPC的意见 健康中的内稳态和胶质瘤形成中的OPC竞争，我们意识到这是两个 同样的硬币，有一个阴/阳的OPC扩散机制，抵消 但在癌症中却失去了控制。虽然RTK信令的Yang网络被很好地研究， 人们对阴网络的了解要少得多，更不用说它们的反作用了。在这里，我们假设， 磷酸化蛋白质组学/蛋白质组学分析和随后使用高灵敏度OPC的候选物验证 竞争平台应该使我们能够提供对这个阴/阳网络的机械见解。为了验证这一 假设，我们已经组建了一个OPC纯化和培养，蛋白质组学分析与 有限的材料，并使用先进的统计和无监督学习方法来预测信号 基于磷酸化蛋白质组学/蛋白质组学图谱的网络。作为一个团队，我们成功地进行了一次试点 这个实验产生了一些候选基因。在本提案的目标1中，我们将验证这些 OPC竞争中的候选基因。在本提案的目标2中，我们将进行进一步的深度剖析 实验，以全面了解控制OPC稳态的信号网络， 竞争我们项目的发现应该激励进一步的功能研究，以清楚地描绘 整个途径，加深我们对OPC稳态的理解，并阐明范式转变 基于OPC竞争概念的胶质瘤治疗策略。

In this proposal, we will address a fundamentally important problem in glia biology: how do oligodendrocyte precursor cells (OPCs) robustly maintain their numbers? Previous intravital imaging experiments demonstrated that OPCs exert mutual inhibition when they contact each other, but promptly enter cell cycle when neighboring OPCs either differentiate or die, and halt proliferation again when homeostasis is achieved. However, the molecular basis behind OPC homeostasis remains largely unknown. Recently, using a mouse genetic system called Mosaic Analysis of Double Markers (MADM) to model glioma, our lab discovered that OPC is a cell of origin for glioma, and revealed that, instead of passively over-expanding, mutant OPCs actually outcompete WT OPCs and eventually take over the entire brain. Most importantly, when we genetically blocked cell competition of mutant OPCs, glioma can be completely prevented. Putting the observations of OPC homeostasis in health and OPC competition in gliomagenesis together, we realized that these are the two sides of the same coin, and that there is a Yin/Yang mechanism for OPC proliferation that counterbalances each other in health but gets deregulated in cancer. While the Yang network of RTK signaling is well studied, the Yin network is much less understood, let alone their counter-interactions. Here, we hypothesize that phospho-proteomic/proteomic profiling and subsequent candidate validation using highly sensitive OPC competition platforms should enable us to provide mechanistic insights into this Yin/Yang network. To test this hypothesis, we have assembled a team of experts on OPC purification and culture, proteomic profiling with limited materials, and using advanced statistical and unsupervised learning approaches to predict signaling network based on phospho-proteomic/proteomic profiles. As a team, we have successfully performed a pilot experiment that led to a handful of candidate genes. In Aim 1 of this proposal, we will validate the role of these candidate genes in OPC competition. In Aim 2 of this proposal, we will perform further in-depth profiling experiments to gain a comprehensive insight into the signaling network that controls OPC homeostasis and competition. The findings from our project should motivate further functional studies to clearly delineate the entire pathway, deepen our understanding of OPC homeostasis, and shed light on paradigm-shifting therapeutic strategies for glioma based on the concept of OPC competition.