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，称为颅神经嵴细胞（CNCC）。这些细胞从发育中的大脑中产生，并迁移到正在形成的头部，在那里它们改变身份或分化成各种细胞类型，如骨和软骨细胞和神经元。通过它们对感觉器官和颌骨的贡献，脊椎动物中CNCC的起源被认为是捕食性进食进化的主要驱动力。考虑到CNCC形成的结构的功能重要性，这些细胞的适当分化是至关重要的，并且通过细胞间通讯来协调。细胞可以通过间隙连接进行交流，间隙连接是由称为连接蛋白的蛋白质形成的相邻细胞之间的小通道。最常见的间隙连接蛋白是连接蛋白43（Cx43），该蛋白在CNCC中表达，并且对于它们向发育头部的迁移是重要的。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使用小鼠和鸡模型确定Cx43在CNCC分化中的作用。为了实现这一目标，我们已经开发了一种小鼠模型，其中Cx43被从神经嵴细胞中特异性地去除，这里称为Cx43cKO。正如预期的那样，Cx43cKO小鼠的头骨形状发生了改变，这些形状变化局限于CNCC衍生的区域。为了确定Cx43在CNCC分化中的作用，我们将比较Cx43cKO和对照小鼠之间CNCC起源的单细胞内的基因表达，提供参与该细胞过程的基因列表。为了了解这些靶基因是如何介导CNCC分化的，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。这些研究将为与干细胞分化有关的基本问题提供答案，更广泛地说，头骨发育和进化，有助于使加拿大处于这一充满活力和不断扩大的科学领域的最前沿。此外，学员将获得宝贵的专业和技术技能，使他们能够在学术界和工业界成功就业，促进加拿大的经济。

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.