Cellular and Genetic Determinants of Great Vessel Morphogenesis

涉及离开心脏的大动脉（例如“大血管”）的畸形是 先天性心血管缺陷（CCD）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。在胚胎发生过程中， 大血管来自六对两侧对称的动脉， 咽弓经历广泛的重塑， 在出生时出现的模式。虽然重塑方面已经被广泛研究， 咽弓动脉的发育起源和遗传程序 规范它们的规格仍然难以捉摸。由于严重的大血管缺损 与生命不相容和轻度缺陷导致CCD，我们的长期目标是 阐明PAA内皮细胞的细胞来源并确定遗传途径 介导PAA建立以潜在地鉴定新的人类疾病基因。 斑马鱼模式生物允许无与伦比的实时可视化， PAA发育的遗传解剖。通过对一部小说的研究 Tg（nkx2.5：：ZsYellow）报告基因，在PAA中发现了ZsYellow荧光 内皮细胞这一观察结果是令人惊讶的，因为nkx2.5转录本在小鼠中未被检测到。 这个人口。基于这些数据，我们假设PAA内皮细胞来源于 早期的nkx2.5+细胞来源，其中ZsYellow荧光持续存在。 虽然完全未经探索，但传统的nkx2.5支持这一假设。 小鼠cre/loxP谱系追踪。因此，nkx2.5很可能是保守的，但 迄今尚未认识到，在大型船舶建立中的作用，需要进一步 调查我们的初步数据还表明，nkx2.5和一个必要的 TGF β通路组分，潜伏TGF β结合蛋白3（LTBP 3），是 PAA的发展，但诱导剩余的脉管系统。基于 令人信服的初步数据，包括遗传谱系追踪，功能丧失， 基因表达的研究，我建议测试的假设，LTBP 3介导的TGF？ 来自第二心脏区域（SHF）的信号传导促进内皮细胞分化， 表达nkx2.5的PAA祖细胞。开发出了新的试剂 nkx2.5+祖细胞及其衍生物，我们的实验室有独特的机会，直接 测试这个假设。由于PAA缺陷会导致CCD或胚胎死亡，因此建议 研究对于改进治疗方法是重要的。

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.