Role of Connexin 43 in Cranial Neural Crest Cell Differentiation

面部和头骨的大部分是由一种特殊类型的干细胞形成的，这种干细胞被称为脑神经脊细胞(CNCC)。这些细胞来自发育中的大脑，并迁移到形成头部，在那里它们改变身份或分化为各种类型的细胞，如骨、软骨细胞和神经元。通过它们对感觉器官和颌骨的贡献，脊椎动物中CNCCs的起源被认为是捕食性进食进化的主要驱动力。鉴于CNCC形成的结构在功能上的重要性，这些细胞的适当分化是至关重要的，并通过细胞间的通讯进行协调。细胞可以通过缝隙连接进行交流，缝隙连接是相邻细胞之间的小通道，由称为连接蛋白的蛋白质形成。最常见的缝隙连接蛋白是连接蛋白43(Cx43)，该蛋白在CNCC中表达，对其向发育中的头部迁移具有重要作用。然而，Cx43在CNCC分化中的作用仍不清楚。因此，我们合作的主要目标是利用小鼠和鸡的模型来确定Cx43在CNCC分化中的作用。为了实现这一目标，我们开发了一种小鼠模型，在该模型中，Cx43特定地从神经脊细胞中移除，这里称为Cx43cKO。正如预期的那样，Cx43cKO小鼠的头骨形状发生了变化，这些形状变化局限于CNCC来源的区域。为了确定Cx43在CNCC分化中的作用，我们将比较Cx43cKO和对照组小鼠在CNCC起源的单个细胞中的基因表达，提供参与这一细胞过程的基因清单。为了了解这些靶基因如何介导CNCC分化，我们将使用鸡模型，在该模型中，我们可以通过实验操作感兴趣的基因来快速评估基因功能。这些研究将提供与干细胞分化相关的基本问题的答案，更广泛地说，提供头骨发育和进化的答案，帮助加拿大走在这一充满活力和不断扩大的科学领域的前沿。此外，受训者将获得宝贵的专业和技术技能，这将使他们能够在学术界和工业界成功就业，促进加拿大经济的发展。

Much of the face and skull is formed by a special type of stem cells, called cranial neural crest cells (CNCCs). These cells arise from the developing brain and migrate into the forming head where they change identity, or differentiate, into a variety of cell types such as bone and cartilage cells and neurons. Through their contribution to the sensory organs and jaws, the origin of CNCCs in vertebrates is considered the main driver of predatory feeding evolution. Given the functional importance of the structures formed by CNCCs, proper differentiation of these cells is crucial, and is coordinated by cell-cell communication. Cells can communicate through gap junctions, which are small channels between adjacent cells formed by proteins called connexins. The most common gap junction protein is connexin 43 (Cx43), and this protein is expressed in CNCCs and is important for their migration to the developing head. However, the role of Cx43 in CNCC differentiation remains obscure. Therefore, the main objective of our collaboration is to determine the role of Cx43 in CNCC differentiation using mouse and chick models. To accomplish this objective, we have developed a mouse model wherein Cx43 is removed specifically from neural crest cells, known here as Cx43cKO. As expected, skull shape is altered in Cx43cKO mice, and these shape changes are localized to regions derived from CNCCs. To determine the role of Cx43 in CNCC differentiation, we will compare gene expression within single cells of CNCC origin between Cx43cKO and control mice, providing a list of genes involved in this cellular process. To understand how these target genes mediate CNCC differentiation, we will use the chick model where we can experimentally manipulate genes of interest to rapidly evaluate gene function. These studies will provide answers to fundamental questions related to stem cell differentiation, and, more broadly, skull development and evolution, helping to put Canada at the forefront of this vibrant and expanding scientific field. Additionally, trainees will gain valuable professional and technical skills that will position them for successful employment in academia and industry, enhancing Canada's economy.