Coordinate regulation of erythroid and macrophage lineages in development by EKLF/KLF1

摘要 红系细胞在体内成熟，有支持的巨噬细胞；这种细胞-细胞 隔室被称为红细胞岛，这一实体在50多年前首次被描述。红细胞 与巨噬细胞的相互作用对于最佳的营养获取、生存、增殖和 红血球分化。 我们提出的实验解决了一个令人兴奋的想法，即红血球Krüppel样因子(EKLF； KLF1)不仅在红细胞中建立适当的基因表达模式方面发挥着内在的作用 但它还通过一种外在机制影响这一过程 基于其在岛状巨噬细胞内的惊人表达以及在 红系祖细胞(EMP)。我们的研究建立在初级或低级观察的基础上。 在活体分析和EKLF救援系统的帮助下，操纵的细胞。 我们发现E8.5期卵黄囊的EMP中有EKLF的表达。的实验。 目标1稍后将研究EKLF在指导这些细胞的功能潜能中的作用 胚胎和成体的各个阶段。 我们发现，巨噬细胞限制性消融EKLF外源性影响红细胞。 AIM 2的实验将检验与铁有关的红细胞效应假说，该假说可能 对恢复压力很重要。 我们发现胎儿肝岛巨噬细胞表现出独特的基因表达特征 这受到EKLF的广泛监管。AIM 3的实验将评估EKLF在岛屿上的作用 巨噬细胞识别，这项研究将扩展到对人类细胞的分析。 了解这些基本机制最终将有助于理解 出现在循环中有核红细胞水平较高的贫血中，例如 先天性IV型红细胞生成性贫血(CDA)，以及能够 人类细胞来源的高效扩增和去核，供临床使用。

SUMMARY Erythroid cells mature in vivo in the presence of a supportive macrophage; this cell-cell compartment is known as the erythroblastic island, an entity first described over 50 years ago. Red cell interactions with the macrophage are critical for optimal nutrient access, survival, proliferation, and differentiation of the erythron. Our proposed experiments address the exciting idea that Erythroid Krüppel-like Factor (EKLF; KLF1) not only plays an intrinsic role in establishing the proper gene expression patterns in the red cell within the erythroblastic island, but that it additionally affects this process by an extrinsic mechanism based on its surprising expression within the island macrophage and early in development within the erythro-myeloid progenitor (EMP). Our studies build on observations made in primary or minimally manipulated cells, aided by in vivo assays and EKLF rescue systems. We have found that EKLF is expressed in the EMP in the yolk sac by E8.5. The experiments of Aim 1 will investigate the role of EKLF in directing the functional potential of these cells at later stages in the embryo and in the adult. We have found that macrophage-restricted ablation of EKLF extrinsically affects the red cell. The experiments of Aim 2 will examine an iron-related hypothesis for the red cell effect that may be important for stress recovery. We have found that fetal liver island macrophage display a unique gene expression signature that is extensively regulated by EKLF. The experiments of Aim 3 will assess EKLF's role in island macrophage identity, studies that will be extended to analysis of human cells. Understanding these basic mechanisms will ultimately aid in understanding the problems that arise in anemias that present with high levels of nucleated red blood cells in circulation, such as congenital dyserythropoietic anemia (CDA) type IV, and in the design of culture systems that enable efficient expansion and enucleation of human cell sources for clinical use.