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则 和伤口再生。对生物化学信号的理解是非常先进的。然而，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的作用， 再生（McLaughlin和Levin 2018 16; Li等人，2020 5）和伤口愈合（Zhao et al. 2012 32）是 增长.我们的研究目标是研究发育和再生的机制， 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，羽毛芽伸长的方向是由同步的 在芽真皮细胞中振荡钙通道活性，其由表皮Shh信号传导控制（Li et 例如，2018年11月）。第二，皮肤经常显示色素条纹沿着身体。的尺寸和间距 日本鹌鹑的纵向色素沉着条纹最近被证明是自主控制的， 黑素细胞祖细胞群以间隙连接依赖的方式（Inaba等，2019年12月）。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， 这一过程不能用经典的图灵反应扩散机制来解释（图中的图案化）。 微米范围）。这些结果促使我们认真思考大规模组织结构是如何构建的。而 涉及形态发生素的局部信号传导中心（例如，WNT、BMP、FGF）被显示启动周期性的 羽毛/毛芽的图案，一些未知的机制，能够动态跨越很大的距离 必须共同努力，在长距离范围内传播信息（Inaba和Chuong，2019年15）。 这里的生物电工作提供了一个线索。因此，我们组织了一个多学科团队来分析 生物化学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，通过缝隙连接偶联细胞的瞬时生物电信号， 集合可以允许具有最小衰减的快速、长距离信令。电势梯度是 利用它来长距离快速传播信号（以毫秒为单位的毫米）， 细胞内的信使和模式更大的形态发生领域。发育中的禽类皮肤外植体 由于可量化的不同模式，平面拓扑结构更易于通道，因此提供了一个出色的模型 活动可视化，电流扰动和光遗传基因激活-在小鼠中不容易 模型实验上，我们将首先衡量内源性生物电景观和评估的重要性， 在这两个组织图案化过程中的生物电（目的1A，2A）。然后我们将研究离子通道/ 间隙连接与生物化学信号相互作用以获得组织模式（目的1B，2B）。这项工作很可能 为未来的应用提供新的发现和见解，以利用生物电促进伤口再生。

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.