Effect of Heme on mRNA and miRNA Profile

血红素[铁原卟啉]是地球上几乎所有生命赖以生存的原始大循环。它有 多种已知功能和不同的性质。血红素的正常途径和调控的重要性 疾病的严重性强调了新陈代谢，在这些疾病中，存在着血红素稳态的缺陷。 例如，卟啉症是一组疾病，在这些疾病中，正常的血红素合成存在缺陷， 主要是由于新陈代谢的先天缺陷，导致正常的卟啉和 血红素合成。在血红素代谢中特别重要的基因及其产物是丙氨酸合成酶1 [ALAS1]和[Hmox1]，分别是血红素合成和血红素合成的速率控制酶。 分解代谢。羟甲基丁烷合成酶[HMBS]是血红素生物合成途径的第三个酶，是 缺乏急性间歇性卟啉，是急性卟啉病中最严重的。最近，我们报道了 MiRNAs-122、-196和-let 7对Hmox1及其关键抑制因子表达的重要新影响 BACH1，我们最近发现了蛋白酶体和其他蛋白酶的新的和迄今为止意想不到的作用 调节ALAS1、BACH1和Hmox1水平的通路。我们还发现由以下因素引起的变化 血红素过量与血红素缺乏对人肝细胞miRNAs和mRNAs相互表达的影响。 血红素，这是治疗急性卟啉病发作和预防的首选方法，可能有 对肝脏和其他组织和器官的有害影响，尤指反复使用。我们最近 基因芯片结果在人类Huh-7细胞中揭示了血红素过量与血红素缺乏对 几个基因和途径。现在重要的是评估变化的潜在生理重要性。 在体外模型中的miRNA和mRNA图谱以及体内是否发生类似的变化以及在多大程度上发生类似的变化， 在AIP的动物模型和患有急性卟啉症的人类中。我们假设亚铁血红素和其他 金属卟啉通过改变选定的microRNAs和Hmox1来调节ALAS1、HMBS和Hmox1的表达 我们的具体目标如下：目标1：描述作用和机制 由此选择的microRNAs调节ALAS1、HMBS和Hmox1和/或它们的密钥的表达 人体肝细胞中的调节剂。目的#2描述精选的生理学效果 相应剂量的血红素对突变小鼠的肝脏、肾脏、脾和骨髓 与人类AIP和AIP患者外周血单核细胞相似 他们正在接受亚铁血红素治疗。这些研究的结果将为我们提供对 血红素在健康和疾病中的多种重要作用，以及在我们对基础和 临床层面。

Heme [iron protoporphyrin] is a primordial macrocycle upon which nearly all life on earth depends. It has manifold known functions and diverse properties. The importance of a normal pathway and regulation of heme metabolism is underscored by the seriousness of diseases in which there are defects in heme homeostasis. For example, the porphyrias are a group of diseases in which there are defects in normal heme synthesis, due mainly to inborn errors of metabolism that produce deficient activities of the enzymes of normal porphyrin and heme synthesis. Genes and their products of particular importance in heme metabolism are ALA synthase 1 [ALAS1] and heme oxygenase 1 [HMOX1], respectively, the rate-controlling enzymes of heme synthesis and catabolism. Hydroxymethylbilane synthase [HMBS], the third enzyme of the heme biosynthetic pathway, is deficient in acute intermittent porphyria, the most severe of the acute porphyrias. Recently, we reported important novel effects of miRNAs-122, -196, and -let 7 on expression of HMOX1 and its key repressor BACH1, and we recently discovered new and heretofore unexpected roles of proteasomal and other protease pathways that regulate levels of ALAS1, BACH1, and HMOX1. We also have discovered changes caused by heme excess vs heme deficiency on reciprocal expression of miRNAs and mRNAs in human hepatocytes. Heme, which is the treatment of choice for acute porphyric attacks and for their prevention, may have deleterious effects on the liver and other tissues and organs, especially with repeated use. Our recent microarray results in human Huh-7 cells have unveiled novel effects of heme excess vs heme deficiency on several genes and pathways. It is important now to assess the potential physiological importance of alterations in miRNA and mRNA profiles in in vitro models and whether and to what extent similar changes occur in vivo, in animal models of AIP and in humans with acute porphyrias. We hypothesize that heme and other metalloporphyrins regulate ALAS1, HMBS and HMOX1 expression by altering selected microRNAs and mRNA profiles Our specific aims are as follows: Aim #1: To delineate effects and mechanisms whereby selected microRNAs modulate expression of ALAS1, HMBS, and HMOX1 and/or their key regulators in human hepatocytes. Aim #2 To characterize the effects of selected, physiologically relevant doses of heme on the livers, kidneys, spleens, and bone marrows of mice with mutations that resemble those seen in human AIP and on peripheral blood mononuclear cells of patients with AIP who are receiving heme as therapy. Results of these studies will provide important new insights into the manifold and critical functions of heme in health and disease, and in our understanding at both the basic and clinical level.