Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
J Innate Immun. 2012;4(5-6):446-53. doi: 10.1159/000336423. Epub 2012 Mar 21.
As a principal aspect of their scavenging function, splenic and hepatic macrophages phagocytize and degrade senescent and damaged erythrocytes to recover iron, mainly for the production of hemoglobin in new erythrocytes but also for other carriers and enzymes requiring iron. Splenic red pulp macrophages are specialized for iron recycling with increased expression of proteins for the uptake of hemoglobin, breakdown of heme and the export of iron. In humans, recycling macrophages contribute the majority of the iron flux into extracellular fluid, exceeding the contribution of dietary iron absorption and release of stored iron from hepatocytes. Iron release from macrophages is closely regulated by the interaction of hepcidin, a peptide hormone produced by hepatocytes, with the macrophage iron exporter ferroportin. In addition to their homeostatic role, macrophages employ multiple mechanisms to contain microbial infections by depriving microbes of iron. This review discusses the iron-scavenging function of macrophages in the context of iron homeostasis and host defense.
作为其清除功能的主要方面，脾和肝巨噬细胞吞噬和降解衰老和受损的红细胞以回收铁，主要用于新红细胞的血红蛋白生成，但也用于其他需要铁的载体和酶。脾红髓巨噬细胞专门用于铁的再循环，其摄取血红蛋白、分解血红素和输出铁的蛋白表达增加。在人类中，再循环巨噬细胞对细胞外液中铁通量的贡献最大，超过了膳食铁吸收和肝细胞储存铁释放的贡献。巨噬细胞中铁的释放受到由肝细胞产生的肽激素——铁调素与巨噬细胞铁输出蛋白 Ferroportin 相互作用的密切调节。除了其维持体内平衡的作用外，巨噬细胞还通过剥夺微生物的铁来利用多种机制来控制微生物感染。本综述讨论了巨噬细胞在铁稳态和宿主防御中的铁清除功能。
