Gotardo Érica Martins Ferreira, dos Santos Aline Noronha, Miyashiro Renan Akira, Gambero Sheley, Rocha Thalita, Ribeiro Marcelo Lima, Gambero Alessandra
Clinical Pharmacology and Gastroenterology Unit, Sao Francisco University Medical School.
J Nutr Sci Vitaminol (Tokyo). 2013;59(5):454-61. doi: 10.3177/jnsv.59.454.
Since the discovery that hepcidin is expressed in the adipose tissue of obese subjects, attention has been increasingly focused on alterations in iron homeostasis that are associated with adiposity. We examined the production of hepcidin, the expression of hepcidin-related genes and the iron content of the adipose tissue in obesity using Swiss mice fed a high-fat diet (HFD). The mice were maintained on a control diet or HFD for 12 or 24 wk, and body weight, adiposity and glucose homeostasis were evaluated. The expression of several genes (hepcidin, TfR1, TfR2, DMT1, FT-heavy, ferroportin, IRP-1, IRP-2 and HIF-1) and the protein expression of hepcidin and IL-6 were quantified. The iron level was assessed using a Prussian blue reaction in paraffin-embedded tissue. After 24 wk on the HFD, we observed increases in the levels of hepcidin in the serum and the visceral adipose tissue. The IL-6 levels also increased in the visceral adipose tissue. Adipocytes isolated from the visceral adipose tissues of lean and obese mice expressed hepcidin at comparable levels; however, isolated macrophages from the stromal vascular fraction expressed higher hepcidin levels. Adipose tissues from obese mice displayed increased tfR2 expression and the presence of iron. Our results indicate that IL-6 and iron may affect the signaling pathways governing hepcidin expression. Thus, the mice fed HFD for 24 wk represent a suitable model for the study of obesity-linked hepcidin alterations. In addition, hepcidin may play local roles in controlling iron availability and interfering with inflammation in adipose tissue.
自从发现铁调素在肥胖受试者的脂肪组织中表达以来,人们越来越关注与肥胖相关的铁稳态改变。我们使用喂食高脂饮食(HFD)的瑞士小鼠,研究了肥胖状态下铁调素的产生、铁调素相关基因的表达以及脂肪组织中的铁含量。将小鼠维持在对照饮食或HFD上12周或24周,并评估体重、肥胖程度和葡萄糖稳态。对几种基因(铁调素、转铁蛋白受体1、转铁蛋白受体2、二价金属离子转运体1、铁蛋白重链、铁转运蛋白、铁调节蛋白-1、铁调节蛋白-2和缺氧诱导因子-1)的表达以及铁调素和白细胞介素-6的蛋白表达进行了定量分析。使用普鲁士蓝反应评估石蜡包埋组织中的铁水平。在HFD喂养24周后,我们观察到血清和内脏脂肪组织中铁调素水平升高。内脏脂肪组织中的白细胞介素-6水平也升高。从瘦小鼠和肥胖小鼠的内脏脂肪组织中分离出的脂肪细胞表达铁调素的水平相当;然而,从基质血管部分分离出的巨噬细胞表达的铁调素水平更高。肥胖小鼠的脂肪组织显示转铁蛋白受体2表达增加且存在铁。我们的结果表明,白细胞介素-6和铁可能影响调控铁调素表达的信号通路。因此,喂食HFD 24周的小鼠是研究肥胖相关铁调素改变的合适模型。此外,铁调素可能在控制脂肪组织中铁的可用性和干扰炎症方面发挥局部作用。