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

总结 红系细胞在支持性巨噬细胞的存在下在体内成熟;这种细胞-细胞 隔室被称为成红细胞岛，这是50多年前首次描述的实体。红细胞 与巨噬细胞的相互作用对于获得最佳营养、存活、增殖和 的差异化。 我们提出的实验解决了一个令人兴奋的想法，即红系Krüppel样因子（EKLF; KLF 1）不仅在红细胞中建立适当的基因表达模式中起着内在的作用， 在成红细胞岛内，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令人惊讶的表达以及在发育早期在 红骨髓祖细胞（EMP）。我们的研究建立在对初级或最低限度的观察基础上。 操作的细胞，通过体内测定和EKLF拯救系统辅助。 我们发现EKLF在E8.5表达于卵黄囊的EMP中。的实验 目的1探讨EKLF在指导这些细胞功能潜能中的作用， 在胚胎和成年阶段。 我们已经发现，巨噬细胞限制性消融EKLF外膜影响红细胞。 目标2的实验将检验与铁有关的红细胞效应假设， 对压力恢复很重要 我们发现胎肝岛巨噬细胞显示出独特的基因表达特征 这是由EKLF广泛监管的。目标3的实验将评估EKLF在岛屿中的作用 巨噬细胞的身份，研究将扩展到人类细胞的分析。 理解这些基本机制将最终有助于理解 出现于循环中存在高水平有核红细胞的贫血，例如 先天性红细胞生成不良性贫血（CDA）IV型，并在培养系统的设计，使 用于临床应用的人细胞来源的有效扩增和去核。

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.