Bastin Judy, Drakesmith Hal, Rees Margaret, Sargent Ian, Townsend Alain
Molecular Immunology Group, Weatherall Institute of Molecular Medicine, Oxford University, John Radcliffe Hospital.
Br J Haematol. 2006 Sep;134(5):532-43. doi: 10.1111/j.1365-2141.2006.06216.x.
Two anatomical sites that are important in human iron metabolism are the liver and placenta. Liver macrophages recycle iron from erythrocytes, and the placenta transfers iron from the mother to the fetus. The cellular distribution of proteins involved in iron transport in these two sites was studied. Transferrin receptor-1 (TfR1) and Ferroportin (FPN) expression was found on the placental syncytiotrophoblast (STB) and were polarised such that TfR1 was on the apical maternal-facing membrane and FPN was on the basal fetal-facing membrane, consistent with unidirectional iron transport from mother to fetus. Ferritin was strongly expressed in the stroma, suggesting that fetal tissue can store and accumulate iron. HFE was on some parts of the basal STB and, where present, HFE clearly colocalised with FPN but not TfR1. In the stroma, both HFE and FPN were present on CD68+ Hofbauer macrophage cells. In liver, the location of HFE is controversial. Using four mouse monoclonals and two polyclonal sera we showed that the pattern of HFE expression mirrored the distribution of CD68+ macrophage Kupffer cells. FPN was also most strongly expressed by CD68+ Kupffer cells. These findings contribute to understanding how iron is transported and stored in the human placenta and liver.
在人体铁代谢中起重要作用的两个解剖部位是肝脏和胎盘。肝脏巨噬细胞从红细胞中回收铁，而胎盘将铁从母体转移到胎儿。研究了这两个部位参与铁转运的蛋白质的细胞分布。发现转铁蛋白受体-1（TfR1）和铁转运蛋白（FPN）在胎盘合体滋养层（STB）上表达，且呈极化分布，使得TfR1位于面向母体的顶端膜上，FPN位于面向胎儿的基底膜上，这与铁从母体到胎儿的单向转运一致。铁蛋白在基质中强烈表达，表明胎儿组织可以储存和积累铁。HFE在基底STB的某些部位存在，且在有HFE的地方，它明显与FPN共定位，但不与TfR1共定位。在基质中，HFE和FPN都存在于CD68 +霍夫鲍尔巨噬细胞上。在肝脏中，HFE的定位存在争议。使用四种小鼠单克隆抗体和两种多克隆血清，我们表明HFE的表达模式反映了CD68 +巨噬细胞库普弗细胞的分布。FPN也在CD68 +库普弗细胞中表达最强。这些发现有助于理解铁在人胎盘和肝脏中的转运和储存方式。
