Turato Cristian, Kent Patricia, Sebastiani Giada, Cannito Stefania, Morello Elisabetta, Terrin Liliana, Biasiolo Alessandra, Simonato Davide, Parola Maurizio, Pantopoulos Kostas, Pontisso Patrizia
Veneto Institute of Oncology, IOV - IRCCS, Padua, Italy.
McGill University, Montreal, Quebec, Canada.
J Investig Med. 2018 Jan;66(1):32-38. doi: 10.1136/jim-2017-000473. Epub 2017 Sep 20.
Iron overload results in cellular toxicity, tissue injury, organ fibrosis and increased risk of neoplastic transformation. SerpinB3 is a serine protease inhibitor overexpressed in the liver in oxidative stress conditions, able to induce fibrosis and increased risk of malignant transformation. Aim of the present study was to assess the effect of iron overload on SerpinB3 expression in the liver using in vivo and in vitro models.The expression of Serpinb3 was assessed in the liver of hemojuvelin knockout mice (Hjv-/-), an established model of hereditary hemochromatosis, and of wild type control mice, following dietary or pharmacological iron manipulation. To assess the direct effect of iron in vitro, cell lines were treated with different concentration of hemin or with an iron chelator.Hepatic Serpinb3 mRNA and protein were highly expressed in Hjv-/- mice, but not in wild type controls fed with a standard diet. Serpinb3 became detectable in wild type mice fed with a high iron diet or injected with iron dextran; these treatments further induced Serpinb3 expression in Hjv-/- mice. Livers expressing Serpinb3 showed a positive staining also for HIF-2α in the same areas. Hemin promoted induction of SerpinB3 mRNA in HeLa and HA22T/VGH cells, but a mild stimulation of SerpinB3 promoter activity in HeLa and Huh7 cells. In conclusion, Serpinb3 is strongly induced by iron in the mouse liver. The molecular link between iron, ROS and SerpinB3 seems to be HIF-2α, which is induced by iron overload and was previously found capable of up-regulating SerpinB3 at the transcriptional level.
铁过载会导致细胞毒性、组织损伤、器官纤维化以及肿瘤转化风险增加。丝氨酸蛋白酶抑制剂B3（SerpinB3）是一种在氧化应激条件下于肝脏中过度表达的丝氨酸蛋白酶抑制剂，能够诱导纤维化并增加恶性转化风险。本研究的目的是使用体内和体外模型评估铁过载对肝脏中SerpinB3表达的影响。在遗传性血色素沉着症的既定模型——血色素沉着蛋白敲除小鼠（Hjv-/-）以及野生型对照小鼠的肝脏中，评估了饮食或药物性铁处理后Serpinb3的表达。为了在体外评估铁的直接作用，用不同浓度的血红素或铁螯合剂处理细胞系。Hjv-/-小鼠肝脏中的Serpinb3 mRNA和蛋白高度表达，但喂食标准饮食的野生型对照小鼠中则不然。在喂食高铁饮食或注射右旋糖酐铁的野生型小鼠中可检测到Serpinb3；这些处理进一步诱导了Hjv-/-小鼠中Serpinb3的表达。表达Serpinb3的肝脏在相同区域也显示HIF-2α呈阳性染色。血红素促进了HeLa和HA22T/VGH细胞中SerpinB3 mRNA的诱导，但对HeLa和Huh7细胞中SerpinB3启动子活性有轻度刺激作用。总之，铁在小鼠肝脏中强烈诱导Serpinb3。铁、活性氧（ROS）和SerpinB3之间的分子联系似乎是HIF-2α，它由铁过载诱导，且先前已发现其能够在转录水平上调SerpinB3。
