Channel activity during skin morphogenesis

我们的长期目标是了解在发育过程中协调皮肤形态发生的原理 和伤口再生。对生化信号的理解有了很大的进步。然而，对这一问题的研究 非神经生物电的作用滞后，尽管有证据表明生物电在发育中发挥作用， 再生(McLaughlin和Levin 2018年16；Li等人，2020年5)和伤口愈合(赵等人。2012年32)是 不断增长。我们的研究目标是研究人类胚胎发育和再生的机制。 皮肤附属物。在我们最近的两篇研究论文中，我们受到启发，看到生物电在两个 组织图案化过程。首先，伸长羽芽的取向是由 花蕾真皮细胞中受表皮Shh信号控制的振荡钙通道活动(Li ET Al.，2018 11)。其次，皮肤经常会在身体上出现色素条纹。的大小和间距 日本鹌鹑的纵向着色条纹最近被证明是自主控制在 黑素细胞前体细胞群以缝隙连接依赖的方式(Inaba等人，2019年12)。当时 这些周期性的黑/黄条纹在胚胎中形成，间隔以毫米为单位，形成大规模的图案 不能用经典图灵反应-扩散机制(图案化)解释的过程 微米范围)。这一结果促使我们认真思考大规模组织架构是如何构建的。而当 涉及形态原(如WNT、BMP、成纤维细胞生长因子)的局部信号中心被证明启动周期性 羽毛/毛芽的图案，一些未知的机制，能够动态地跨越很长的距离 必须共同努力，在远距离范围内传递信息(Inaba和Chuong，2019 15)。 这里的生物电工作提供了一条线索。因此，我们组织了一个多学科团队来分析 关于生化和生物电信号如何整合以实现大规模组织图案化的机制。 我们假设，在其他可能性中，跨越缝隙连接耦合细胞的瞬时生物电信号 集合体可以以最小的减量实现快速、远距离的信令。电位梯度为 用于在远距离(毫秒单位为毫米)快速传播信号，以调节 细胞内的信使，并形成更大的形态发生场。发展中的禽类皮肤外植体 提供了一个出色的模型，因为它具有可量化的不同模式，平面拓扑结构使渠道更容易 活动可视化、电流扰动和光遗传基因激活--在小鼠中不容易 模特。在实验上，我们将首先测量内生生物电景观并评估其重要性。 在这两种组织图案化过程中的生物电(目标1A、2A)。然后我们将研究离子通道/ 缝隙连接与生化信号串扰以实现组织模式(目标1B、2B)。这项工作很可能会 为利用生物电促进伤口再生的未来应用提供新的发现和见解。

Our long-term objective is to understand the principles that orchestrate skin morphogenesis in development and wound regeneration. The understanding of biochemical signaling is well advanced. Yet, research into the roles of non-neural bioelectricity lags behind, although evidence for a role of bioelectricity in development, regeneration (McLaughlin and Levin 2018 16; Li et al., 2020 5) and wound healing (Zhao et al. 2012 32) is growing. Our research objective is to study the mechanisms underlying the development and regeneration of skin appendages. In two of our recent research papers, we were inspired to see bioelectricity in action in two tissue patterning processes. First, the orientation of elongating feather buds is regulated by synchronization of oscillating calcium channel activities in bud dermal cells, which is controlled by epidermal Shh signaling (Li et al., 2018 11). Second, the skin frequently shows pigment stripes along the body. The size and spacing of longitudinal pigmentation stripes in Japanese quail was recently shown to be controlled autonomously within melanocyte progenitor populations in a gap junction-dependent manner (Inaba et al., 2019 12). At the time these periodic black/yellow stripes form in embryos, the spacing is in millimeters, a large-scale patterning process that cannot be explained by the classical Turing reaction-diffusion mechanism (patterning in micrometer range). The results led us to think hard about how large-scale tissue architecture is built. While localized signaling centers involving morphogens (e.g., WNT, BMP, FGF) were shown to initiate periodic patterning of feather/hair buds, some unidentified mechanism capable of spanning large distances dynamically must work together to transduce the information over the long-distance scale (Inaba and Chuong, 2019 15). Bioelectricity work here provides a clue. Thus, we organized a multi-disciplinary team to analyze the mechanisms on how biochemical and bioelectric signals integrate to achieve the large-scale tissue patterning. We hypothesize, among other possibilities, transient bioelectrical signaling across gap-junction-coupled cell collectives may allow rapid, long-distance signaling with minimal decrement. Electropotential gradients are harnessed to propagate signals rapidly over the long distance (millimeters in milliseconds) to regulate intracellular messengers and pattern the much larger morphogenetic field. The developing avian skin explants provide an excellent model because of the quantifiable distinct patterns, planar topology for easier channel activity visualization, electric current perturbation and optogenetic gene activation – not easy in the mouse model. Experimentally, we will first gauge the endogenous bioelectric landscape and evaluate the importance of bioelectricity in these two tissue patterning processes (Aim 1A, 2A). Then we will study how ion channels / gap junctions cross-talk with biochemical signals to achieve tissue patterns (Aim 1B, 2B). The work is likely to produce new findings and insights for future applications to use bioelectricity to benefit wound regeneration.