Micronutrient Laboratory, Nutrition Institute and Food Technology, University of Chile, El Líbano 5524, Macul, Santiago, Chile.
Biometals. 2012 Aug;25(4):749-59. doi: 10.1007/s10534-012-9543-9. Epub 2012 Apr 5.
Adipose tissue secretes numerous pro-inflammatory cytokines, such as interleukin (IL)-6 and tumor necrosis factor (TNF)-α that can lead to insulin resistance (IR). In the liver, both IL-6 and TNF-α induce IR by inhibiting phosphorylation or ubiquitination of IRS1. In IR development, Fe is a risk factor in type-2 diabetes development. We studied the expression of genes related to inflammation, hypoxia, and mitochondrial function in hepatic (HepG2) and adipose (3T3-L1) cells. HepG2 and 3T3-L1 cells were incubated with 20 μM Fe, 40 μM Fe, or 40 μM Fe/20 mM glucose for 7 days and then challenged with 20 ng/ml IL-6 and/or 100 μM CoCl(2) for 20 h. We measured intracellular Fe levels and the relative expression of hepcidin, NF-κB, IL-6, TNF-α, hypoxia inducible factor 1α (HIF-1α), and mitofusin 2 (Mfn-2) mRNA using qRT-PCR. The intracellular Fe concentration in HepG2 cells did not change with 20 or 40 μM Fe. However, levels were decreased with Fe/glucose and IL-6 and/or CoCl(2). 3T3-L1 cells showed an increase in intracellular Fe with high Fe plus either IL-6 or CoCl(2). HepG2 cells incubated with 40 μM Fe alone or Fe/glucose and challenged with IL-6 and/or CoCl(2) showed increased IL-6, NF-κB, and TNF-α mRNA expression and decreased mRNA expression of Mfn-2 in all experimental conditions. 3T3-L1 cells incubated with 40 μM Fe alone or Fe/glucose and challenged with IL-6 showed increased NF-κB mRNA expression and decreased Mfn-2 expression in all experimental conditions. Thus, high Fe, inflammation, and hypoxia trigger the expression of genes related to inflammation and Fe metabolism in HepG2 cells, in 3T3-L1 cells the same stimuli increased NF-kB and hepcidin expression.
脂肪组织分泌许多促炎细胞因子，如白细胞介素 (IL)-6 和肿瘤坏死因子 (TNF)-α，可导致胰岛素抵抗 (IR)。在肝脏中，IL-6 和 TNF-α 通过抑制 IRS1 的磷酸化或泛素化来诱导 IR。在 IR 发展过程中，铁是 2 型糖尿病发展的一个危险因素。我们研究了与炎症、缺氧和线粒体功能相关的基因在肝 (HepG2) 和脂肪 (3T3-L1) 细胞中的表达。将 HepG2 和 3T3-L1 细胞分别用 20 μM Fe、40 μM Fe 或 40 μM Fe/20 mM 葡萄糖孵育 7 天，然后用 20 ng/ml IL-6 和/或 100 μM CoCl2 刺激 20 h。我们使用 qRT-PCR 测量细胞内 Fe 水平和相对表达的铁调素、NF-κB、IL-6、TNF-α、缺氧诱导因子 1α (HIF-1α) 和线粒体融合蛋白 2 (Mfn-2) mRNA。HepG2 细胞的细胞内 Fe 浓度没有因 20 或 40 μM Fe 而改变。然而，Fe/葡萄糖和 IL-6 和/或 CoCl2 会降低其浓度。3T3-L1 细胞在高 Fe 加 IL-6 或 CoCl2 的情况下，细胞内 Fe 水平增加。单独用 40 μM Fe 孵育的 HepG2 细胞或用 Fe/葡萄糖孵育并接受 IL-6 和/或 CoCl2 刺激的 HepG2 细胞，在所有实验条件下均显示出 IL-6、NF-κB 和 TNF-α mRNA 表达增加，而 Mfn-2 mRNA 表达降低。单独用 40 μM Fe 孵育或用 Fe/葡萄糖孵育并接受 IL-6 刺激的 3T3-L1 细胞，在所有实验条件下均显示 NF-κB mRNA 表达增加，Mfn-2 表达降低。因此，高 Fe、炎症和缺氧会引发 HepG2 细胞中与炎症和 Fe 代谢相关的基因表达，而在 3T3-L1 细胞中，相同的刺激会增加 NF-kB 和铁调素的表达。
