NEW IRON TRAFFICKING PATHWAY IN EPITHELIAL INDUCTION

上皮诱导中的新铁运输途径

• 批准号: 7346985
• 负责人: JONATHAN M. BARASCH
• 金额: $ 34.93万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7346985
• 关键词: Adult; Affinity; Antibodies; Autoradiography; Candidate Disease Gene; Carrier Proteins; Catalytic Domain; Cell Survival; Cells; Characteristics; Classification; Complement; Data; Development; Disease; Dose; Drug or chemical Tissue Distribution; Electron Probe Microanalysis; Embryo; Endocytosis; Enzymes; Epithelial; Epithelium; Gene Expression; Genes; Genetic; Genetic screening method; Growth; Human; In Vitro; Iron; Kidney; Kidney Diseases; Ligand Binding; Maps; Measures; Mediating; Mesenchymal; Mesenchyme; Metanephric Diverticulum; Modeling; Molecular Weight; Morphogenesis; Nephrons; Numbers; Organ; Organelles; Organogenesis; Oxidation-Reduction; Pathway interactions; Peripheral; Placenta; Pregnancy; Process; Proteins; Protocols documentation; Regulation; Route; Signal Transduction; Staging; Standards of Weights and Measures; Testing; Thinking; Tissues; Transferrin; Transferrin Receptor; cell type; cytokine; in vivo; in vivo Model; member; nephrogenesis; novel; progenitor; receptor; receptor expression; response; trafficking

We know very little about how developing organs obtain iron, but this topic is of great importance in human gestation. Indeed, organogenesis can initiate in the absence of transferrin/transferrin receptor, and in many lineages, iron delivery by transferrin is stage specific. However, there are few, if any proteins that can substitute for, or complement transferrin. These studies are of general importance because acquisition of iron is required for growth, and it is of local importance, because iron regulates specific subsets of genes by transcriptional and translational effects. My lab is dedicated to finding mechanisms of kidney induction, a process that generates nephrons from mesenchymal cells. We previously identified a set of cytokines that stimulate this conversion and now we have identified a new nephron inducer called Ngal, a member of the lipocalin superfamily. These proteins are not well known, and functional data are limited, but they are thought to transport low molecular weight compounds, which they deliver to cells by endocytosis. We propose that Ngal can transport iron, and that its inductive activity results from iron-Ngal. Ngal was not a substitute for transferrin-they traffic to different organelles and they target different domains in the developing mesenchyme. In vitro, Ngal and transferrin were both required for induction, acting in a sequential fashion. To evaluate Ngal traffic, we will isolate the Ngal receptor. The receptor should describe a domain of cells in the periphery of the kidney that is likely to include epithelial progenitors and stroma and it will describe a unique subcellular pathway. The identification is also important in order to evaluate why Ngal is so highly expressed in a variety, of epithelial diseases. Then we will identify the pool of iron that regulates gene expression and determine how it varies with development by using a novel genetic probe in vivo. The response to this pool of iron is tested by examining candidate genes and microarrays; it appears to include genes that are known to control kidney development. Lastly, we will test the hypothesis that iron delivery is required at particular stages of mesenchymal conversion by first determining whether Ngal requires iron for its inductive activity in vitro, and then examining when and where transferrin is essential in vivo. The later requires rescue of the embryos in vivo. These studies implicate iron as a critical regulator in morphogenesis, and define its stage specific functions during the conversion of mesenchyme to epithelia.

我们对发育中的器官如何获得铁知之甚少，但这个话题在人类妊娠中非常重要。事实上，器官发生可以在转铁蛋白/转铁蛋白受体的情况下启动，并且在许多谱系中，转铁蛋白的铁递送是阶段特异性的。然而，很少有蛋白质可以替代或补充 转铁蛋白这些研究具有普遍重要性，因为铁的获得是生长所必需的，并且具有局部重要性，因为铁通过转录和翻译效应调节特定的基因亚群。 我的实验室致力于发现肾脏诱导的机制，这是一个从间充质细胞产生肾单位的过程。我们以前确定了一组刺激这种转换的细胞因子，现在我们已经确定了一种新的肾单位诱导剂，称为Ngal，脂质运载蛋白超家族的成员。这些蛋白质并不为人所知， 数据是有限的，但它们被认为是运输低分子量化合物，它们通过内吞作用将这些化合物递送到细胞。我们认为Ngal可以运输铁，其诱导活性是由铁-Ngal引起的。Ngal不是转铁蛋白的替代品，它们运输到不同的细胞器，并在发育中的间充质中靶向不同的领域。在体外，Ngal和转铁蛋白都需要诱导，以顺序的方式发挥作用。 为了评估Ngal交通，我们将分离Ngal受体。该受体应描述肾脏外周的细胞域，可能包括上皮祖细胞和基质，并描述独特的亚细胞途径。鉴定对于评估Ngal在各种上皮疾病中如此高表达的原因也很重要。然后，我们将确定调节基因表达的铁池，并确定它是如何调节基因表达的。 在体内使用一种新的基因探针，通过检查候选基因和微阵列来测试对这种铁池的反应;它似乎包括已知控制肾脏发育的基因。最后，我们将通过以下方法检验铁输送在间充质转化的特定阶段是必需的这一假设： 确定Ngal在体外的诱导活性是否需要铁，然后检查转铁蛋白在体内何时何地是必需的。后者需要在体内拯救胚胎。这些研究暗示铁作为一个重要的调节器在形态发生，并确定其特定的阶段间充质上皮细胞的转换过程中的功能。