Uncovering mechanisms controlling notochord vacuole and spine morphogenesis

描述(申请人提供)：在脊椎动物中，脊索在脊椎动物的发育过程中起着关键的信号作用，并在骨形成之前充当胚胎的静水骨架。脊索中央有一个充满液体的大细胞器，即脊索液泡。这些充满液体的空泡在每一种被研究的脊椎动物胚胎中都有描述，包括鱼、两栖动物、鸟类和哺乳动物。在这些物种中，液泡持续存在于椎间盘髓核(IVD)内，远远超过骨骼成熟，在那里它们保持渗透活性并继续发挥信号作用。令人惊讶的是，几乎没有 了解脊索液泡生物发生和维持的分子机制。我们实验室最近对斑马鱼的研究表明，脊索空泡是一种特殊的溶酶体相关细胞器。我们证实了脊索空泡是胚胎发育中前后轴伸长所必需的，并确定了这种充满液体的细胞器在脊柱形态发生中的新作用。我们发现，液泡完整性的丧失会导致脊柱轴扭曲，这与先天性脊柱侧弯(CS)患者的情况相似。因此，脊索在脊椎形态发生中起着至关重要的作用。我们的目标是利用斑马鱼系统来揭示控制脊索空泡形成和维持的分子机制，并表征这些空泡在脊椎形态发生中所起的作用。这些研究将有助于更好地了解先天性脊柱侧弯和其他知之甚少的脊柱缺陷的病因，以及与衰老相关的IVD过程。

DESCRIPTION (provided by applicant): In vertebrates the notochord plays critical signaling roles during vertebrate development and acts as a hydrostatic skeleton for the embryo before bone formation. At the center of the vertebrate notochord is a large fluid-filled organelle, the notochord vacuole. These fluid-filled vacuoles have been described in every vertebrate embryo studied including fish, amphibians, birds, and mammals. In these species the vacuoles persist within the nucleus pulposus of the intervertebral discs (IVD's), well beyond skeletal maturity, where they remain osmotically active and continue to play signaling roles. Surprisingly, little was known about the molecular mechanisms involved in notochord vacuole biogenesis and maintenance. Recent work in zebrafish from our laboratory has shown that notochord vacuoles are specialized lysosome-related organelles. We established that notochord vacuoles are required for antero-posterior (AP) axis elongation during embryonic development and identified a novel role for this fluid filled organelle in spine morphogenesis. We found that loss of vacuole integrity leads to kinks in the spine axis similar to those observed in congenital scoliosis (CS) patients. Thus, the vertebrate notochord plays a critical role in spine morphogenesis. Our goal here is to use the zebrafish system to uncover molecular mechanisms controlling notochord vacuole formation and maintenance and to characterize the role these vacuoles play in spine morphogenesis. These studies will help better understand the etiology of congenital scoliosis and other poorly understood spine defects as well as IVD processes associated with aging.