Cellular and Genetic Determinants of Great Vessel Morphogenesis

涉及心脏出口的大动脉(如“大血管”)的畸形有 先天性心血管缺陷(CCDs)的常见原因。在大多数情况下， 这些异常的遗传基础尚未确定。在胚胎发育过程中， 大血管由嵌入其内的六对两侧对称动脉发出。 咽弓经过广泛的重塑以产生复合体 出生时就存在的模式。虽然重塑方面已经被广泛研究， 咽弓动脉的发育起源及其遗传程序 监管它们的规格仍然难以捉摸。由于严重的大血管缺陷 与生活格格不入和轻微的缺陷引起的ccd，我们的长期目标是 阐明PAA血管内皮细胞来源并确定遗传途径 调解PAA的建立，以潜在地识别新的人类疾病基因。 斑马鱼模型生物体允许无与伦比的实时可视化和 PAA发育的遗传解剖。通过对一部小说的审查 TG(NKX2.5：：ZsHuang)报告线，我们在PAA中发现了Zs黄色荧光 内皮细胞。这一观察结果令人惊讶，因为NKX2.5转录本在 这群人。根据这些数据，我们推测PAA内皮起源于 一个较早的NKX2.5+细胞来源，其中Zs黄色荧光一直存在。 尽管这一假说完全没有被探索过，但它得到了传统NKX2.5的支持 Cre/loxP在小鼠中的谱系追踪。因此，NKX2.5很可能扮演着保守的角色，但 到目前为止，在大型船舶建设中的作用尚未得到承认，需要进一步证明 调查。我们的初步数据还表明，NKX2.5和一个必要的 转化生长因子途径的组成部分，潜伏的转化生长因子结合蛋白3(LTBP3)是必需的。 PAA的发育，但对于剩余的血管系统的诱导是必不可少的。基于 令人信服的初步数据，包括遗传谱系追踪、功能丧失和 基因表达研究，我建议检验LTBP3介导的转化生长因子？的假设 第二心区(SHF)发出的信号促进血管内皮细胞分化 表达NKX2.5的PAA前体细胞。开发了新的照明试剂 NKX2.5+前体及其衍生物，我们的实验室有独特的机会直接 检验这一假设。由于PAA缺陷会导致ccd或胚胎死亡，建议的 研究对于改进治疗方法具有重要意义。

Malformations involving the large arteries that exit the heart (e.g. "the great vessels") are common causes of congenital cardiovascular defects (CCDs). In most circumstances, the genetic basis for these abnormalities has not been identified. During embryogenesis, the great vessels arise from six pairs of bilaterally symmetrical arteries embedded within the pharyngeal arches that undergo extensive remodeling to produce the complex pattern present at birth. Although the remodeling aspects have been extensively studied, the developmental origin of pharyngeal arch arteries (PAAs) and the genetic programs regulating their specification remain elusive. As severe great vessel defects are incompatible with life and milder deficiencies cause CCDs, our long-term goal is to elucidate the cellular source of PAA endothelium and identify genetic pathways mediating PAA establishment to potentially identify novel human disease genes. The zebrafish model organism allows for unparalleled real-time visualization and genetic dissection of PAA development. Through examination of a novel Tg(nkx2.5::ZsYellow) reporter line, we discovered ZsYellow fluorescence in PAA endothelium. This observation was surprising as nkx2.5 transcripts are not detected in this population. Based on these data, we postulate that PAA endothelium derives from an earlier nkx2.5+ cellular source in which ZsYellow fluorescence has persisted. Although completely unexplored, this hypothesis is supported by traditional nkx2.5 cre/loxP lineage tracing in mice. Thus, it is likely that nkx2.5 plays a conserved, yet heretofore unrecognized, role in great vessel establishment that warrants further investigation. Our preliminary data also demonstrate that nkx2.5 and a requisite TGF¿ pathway component, Latent TGF¿ Binding Protein 3 (LTBP3), are required for PAA development, but dispensable for induction of the remaining vasculature. Based on compelling preliminary data that include genetic lineage tracing, loss-of-function, and gene expression studies, I propose to test the hypothesis that LTBP3-mediated TGF¿ signaling from the second heart field (SHF) promotes endothelial differentiation of nkx2.5-expressing PAA progenitors. Having developed new reagents for illuminating nkx2.5+ progenitors and their derivatives, our lab has the unique opportunity to directly test this hypothesis. As PAA defects cause CCDs or embryonic lethality, the proposed studies are significant for improved therapeutic approaches.