title: Proteomic Profiling of Iron Overload-Induced Human Hepatic Cells Reveals Activation of TLR2-Mediated Inflammatory Response.
abstract: BACKGROUND
  Hepatic iron overload is common in patients who have undergone hematopoietic cell transplantation (HCT) and may predispose to peri- and post-HCT toxicity. To better reveal more molecules that might be involved in iron overload-induced liver injury, we utilized proteomics to investigate differentially expressed proteins in iron overload-induced hepatocytes vs. untreated hepatocytes.
  
  
  RESULTS
  HH4 hepatocytes were exposed to ferric ammonium citrate (FAC) to establish an in vitro iron overload model. Differentially expressed proteins initiated by the iron overload were studied by two-dimensional liquid chromatography tandem mass spectrometry (2D-LC-MS) analysis. We identified 93 proteins whose quantity statistically significantly changes under excess hepatocyte iron conditions. Gene Ontology (GO) analysis showed that these differentially expressed proteins in HH4 cells are involved in various biological process including endocytosis, response to wounding, di-, trivalent inorganic cation homeostasis, inflammatory response, positive regulation of cytokine production, and etc. Meanwhile, proteomics data revealed protein level of TLR2 and IL6ST significantly increased 7 times and 2.9 times, respectively, in iron overloaded HH4 cells. Our subsequent experiments detected that FAC-treated HH4 cells can activate IL6 expression through TLR2-mediated inflammatory responses via the NF-κB pathway.
  
  
  CONCLUSIONS
  In this study, we demonstrated that iron overload induced hepatocytes triggering TLR2-mediated inflammatory response via NF-κB signaling pathway in HH4 cells.
authors.affiliation: Wuxi Medical School, Jiangnan University, Wuxi 214122, China. xiangli@jiangnan.edu.cn.
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.affiliation: Key Laboratory of Carbohydrate Chemistry &amp; Biotechnology Ministry of Education, Jiangnan University, Wuxi 214122, China. shiweili099@sohu.com.|School of Biotechnology, Jiangnan University, Wuxi 214122, China. shiweili099@sohu.com.
authors.forename: Shiwei
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Hematology, Wuxi People's Hospital, Wuxi 214023, China. lmzmedsci@163.com.
authors.forename: Mize
authors.initials: M
authors.lastname: Lu
authors.affiliation: Department of Hematology, Wuxi People's Hospital, Wuxi 214023, China. wxygh@medmail.com.cn.
authors.forename: Guohua
authors.initials: G
authors.lastname: Yang
authors.affiliation: Department of Hematology, Wuxi People's Hospital, Wuxi 214023, China. yfshen21cn2012@hotmail.com.
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Hematology, Wuxi People's Hospital, Wuxi 214023, China. 13358111962@189.cn.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
mesh_terms: D005786:Gene Expression Regulation; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology; D007501:Iron / Q000633:toxicity; D019190:Iron Overload / Q000235:genetics / Q000473:pathology; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D016328:NF-kappa B / Q000096:biosynthesis / Q000235:genetics; D018384:Oxidative Stress / Q000187:drug effects; D040901:Proteomics; D015398:Signal Transduction; D051195:Toll-Like Receptor 2 / Q000096:biosynthesis*
chemical_list: D016328:NF-kappa B; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; D007501:Iron
keywords: IL-6; NF-κB; TLR2; iron overload; proteomics