Fueling left-right asymmetry: the role of glycolysis in stomach curvature

项目摘要 几乎每个器官系统都存在大小、形状和/或解剖位置的左右（LR）差异。 因此，异常的LR不对称性（称为异位，HTX）通常会导致多种危及生命的并发症。 涉及复杂畸形和器官间不协调偏侧性的出生缺陷。早期的 建立全球LR不对称性的胚胎事件已经得到了很好的研究，它是后期阶段，器官- 特定LR不对称形态发生事件对正常解剖学至关重要;然而，对于大多数器官， 塑造其个体LR不对称性的分子和细胞过程尚未阐明。这 应用程序将探索新的和令人惊讶的概念，LR不对称的糖酵解- 分解葡萄糖产生ATP的原始代谢途径， 不对称器官形态发生已发表的研究表明，胃的弯曲， 在脊椎动物中保守的典型LR不对称性，依赖于LR不对称重排， 间充质细胞转化为上皮细胞（间充质-上皮转化; MET），导致变薄， 左胃壁扩张。最近的左与右转录组分析随后显示， 在胃弯曲期间，糖酵解酶在胃的左侧上调。作为糖酵解（作为 与线粒体呼吸相反）已知在其它情况下促进上皮-间充质可塑性， 这一出乎意料的发现提出了有趣的可能性，即LR不对称糖酵解可能促进LR 非对称MET驱动曲率形态发生。在拟议的项目中，这一想法将严格 通过利用两种不同两栖动物胚胎的独特属性进行测试，执行代谢组学， 光谱成像、糖酵解通量分析、药理学扰动和左右靶向测试 的基因功能，以确定糖酵解基因的功能（目标1），和糖酵解代谢（目标2）， 胃弯曲形态发生因此，R21的成功完成将证实 前提是器官偏侧性是由糖酵解中的LR不对称性形成的，例如异常的代谢 国家可能助长与偏侧有关的出生缺陷。

Project Summary Left-right (LR) differences in size, shape and/or anatomical position exist in almost every organ system. Consequently, abnormal LR asymmetry (known as heterotaxy, HTX) often leads to multiple, life threatening birth defects involving complex malformations and discordant laterality between organs. While the early embryonic events that establish global LR asymmetry have been well studied, it is the later-stage, organ- specific LR asymmetric morphogenesis events that are critical for normal anatomy; yet, for most organs, the molecular and cellular processes that sculpt their individual LR asymmetries have not been elucidated. This application will explore the novel and surprising concept that LR asymmetries in GLYCOLYSIS—the primordial metabolic pathway that breaks down glucose to generate ATP—are integrally involved in asymmetric organ morphogenesis. Published work has shown that leftward curvature of the stomach, an archetypical LR asymmetry conserved among vertebrates, depends on LR asymmetric rearrangements of mesenchymal cells into an epithelium (mesenchymal-to-epithelial transition; MET), causing thinning and expansion of the left stomach wall. Recent left vs right transcriptome profiling subsequently revealed that glycolysis enzymes are upregulated in the left side of the stomach during curvature. As glycolysis (as opposed to mitochondrial respiration) is known to promote epithelial-mesenchymal plasticity in other contexts, this unexpected finding raises the intriguing possibility that LR asymmetric glycolysis may facilitate the LR asymmetric MET that drives curvature morphogenesis. In the proposed project, this idea will be rigorously tested by exploiting the unique attributes of two different amphibian embryos, executing metabolomics, mass spectrometry imaging, glycolytic flux analyses, pharmacological perturbations, and left- vs right-targeted tests of gene function, to determine the function of glycolysis genes (Aim 1), and glycolytic metabolism (Aim 2) in stomach curvature morphogenesis. Successful completion of this R21 will therefore substantiate the intriguing premise that organ laterality is shaped by LR asymmetries in glycolysis, such that aberrant metabolic states may contribute to the development of laterality-related birth defects.