Iron homeostasis and monocyte differentiation in patients with chronic kidney disease

项目总结 慢性肾脏疾病(CKD)影响着全球10%的人口。超过3700万人 据估计，美国有慢性肾脏病，每1000名美国人中就有2人需要透析或肾脏移植才能存活。 慢性肾脏病有许多全身性并发症，包括贫血和全身铁平衡失调。 肾脏纤维化是所有进展性肾脏疾病的共同最终机制。不幸的是，很少有人 治疗方法可以延缓慢性肾脏病患者肾脏纤维化的进展。肾巨噬细胞 参与肾纤维化病理生理的关键细胞之一。大多数肾巨噬细胞 来源于循环中的单核细胞。在他的K08资助的项目中，阿克霍林博士阐明了 肾纤维化过程中肾巨噬细胞内活性铁库的耗竭。此R03提案将 到目前为止，他提高了破译铁在慢性肾脏病髓系细胞病理行为中的作用的能力 除肾脏巨噬细胞外，还关注其前体细胞--循环单核细胞。根据初步的 数据显示，这一建议的中心假设是，在CKD患者中，循环单核细胞类似于肾脏 巨噬细胞，表现出病理耗竭的细胞内不稳定的铁池唇，这改变了它们的表型，通过 诱导CX3CR1和其他促进趋化和组织侵袭的受体。这一细胞内的补给 通过纠正全身性铁失衡，单核细胞不稳定铁库将与这一水平的降低相关 促炎分化。这一假设将在两个具体目标中得到验证：(1)确定细胞内 慢性肾脏病患者经典、中间和非经典循环单核细胞铁状态及(2) 阐明全身和细胞内铁状态在慢性肾脏病患者单核细胞分化中的作用。 为了验证这一假设，申请者将使用现有的外周血单核细胞库 收集自患有和不伴有功能性或绝对性铁缺乏的CKD儿童和健康对照儿童 孩子们。他将使用单细胞转录和多色流式细胞术方法来评估这些细胞 重点是描述导致后续组织侵袭的表型特征，例如 表达相关趋化因子受体，包括CX3CR1。此外，他还将进行体外评估 从CKD患者采集的人单核细胞直接评估其相关功能特性 有无铁刺激。单核细胞功能特性将在以下背景下进行分析 铁的临床参数、循环和尿液排泄的趋化因子水平以及全身参数 动态平衡。结果 技法 一个 肾 从概述的实验中，将提供初步数据以及 用于单核细胞体外功能测试，以支持K08获奖者申请 R01建议在以下情况下评估铁代谢和铁疗法对髓系细胞的影响 纤维化和慢性肾脏病进展。 H

PROJECT SUMMARY Chronic kidney disease (CKD) affects 10% of the population worldwide. More than 37 million people are estimated to have CKD in the US, and 2 in every 1000 Americans need dialysis or a kidney transplant to survive. CKD has numerous systemic complications including anemia and dysfunctional systemic iron homeostasis. Kidney fibrosis is the final mechanism common for all progressive kidney disorders. Unfortunately, very few therapies are available to slow the progression of kidney fibrosis in patients with CKD. Kidney macrophages are one of the key cells implicated in the pathophysiology of kidney fibrosis. The majority of kidney macrophages originate from circulating monocytes. In his K08-funded project Dr. Akchurin elucidated the pathologic role of depletion of labile iron pool in kidney macrophages in propagation of kidney fibrosis. This R03 proposal will enhance his capabilities of deciphering the role of iron in pathologic behavior of myeloid cells in CKD by now, in addition to kidney macrophages focusing on their precursors, circulating monocytes. Based on the preliminary data, the central hypothesis of this proposal is that in patients with CKD, circulating monocytes, similar to kidney macrophages, exhibit pathologically depleted intracellular labile iron pool LIP, which alters their phenotype by inducing CX3CR1 and other receptors facilitating chemotaxis and tissue invasion. Repletion of this intracellular monocyte labile iron pool through correction of systemic iron imbalance will be associated with reduction of this pro-inflammatory differentiation. This hypothesis will be tested in two specific aims: (1) determine the intracellular iron status of classical, intermediate, and non-classical circulating monocytes in patients with CKD and (2) elucidate the role of systemic and intracellular iron status in the differentiation of monocytes in patients with CKD. To test this hypothesis, the applicant will use the existing repository of peripheral blood mononuclear cells collected from children with CKD with and without functional or absolute iron deficiency and from healthy control children. He will evaluate these cells using single cell transcriptomic and multicolor flow cytometry approaches with the focus on delineating the phenotypic features responsible for subsequent tissue invasion, such as expression relevant chemokine receptors, including CX3CR1. Furthermore, he will perform ex vivo evaluation of human monocytes collected from CKD patients to directly assess their relevant functional characteristics in the presence and absence of iron stimulation. Monocyte functional characteristics will be analyzed I the context of clinical parameters, levels of circulating and urine-excreted chemokines, and systemic parameters of iron homeostasis. Results techniques an kidney from t he outlined experiments will provide preliminary data, as well as experience in for the functional ex-vivo testing of uman monocytes, to support the K08 awardee's application for R01 proposal to evaluate the impact of iron metabolism and iron therapy on myeloid cells in the context of fibrosis and CKD progression. h