Iron-Overload triggers ADAM-17 mediated inflammation in Severe Alcoholic Hepatitis

Sci Rep. 2018 Jul 6;8(1):10264. doi: 10.1038/s41598-018-28483-x.

Abstract

Severe alcoholic hepatitis (SAH) is associated with iron accumulation in hepatocytes/macrophages. This possibly correlates with inflammation and stress but the exact mechanism still remains obscure. To understand the role of iron and the mechanisms of systemic iron-overload, a transcriptomic study of liver and Peripheral Blood -Mononuclear-Cells (PBMCs) was undertaken in SAH patients, with and without hepatic iron-overload. Our results show that iron-overload in hepatocytes/macrophages is due to an increased expression of iron-loading receptors and CD163 signaling cascade. Increase in labile iron pool induces expression of iron-loading, oxidative-stress and inflammatory genes along with expression of CD163 and ADAM17. Increased liver iron correlated with circulatory iron, TNF-α, macrophage activation (sCD163) and peroxide-stress in CD163+macrophages in patients who were iron-overloaded and died. Circulatory TNF-α and sCD163 levels were associated with poor outcome. Temporal iron/Fenton stress induced in healthy monocyte-derived-macrophage (MDM)/Tohoku-Hospital-Pediatrics-1(THP1) cells showed higher expression of iron-regulatory, inflammatory and oxidative-stress genes. These genes could be suppressed by iron-chelation. These results suggest that iron mediates inflammation through ADAM17 induction, resulting in macrophage activation and increased shedding of TNF-α and sCD163. These events could be inhibited with iron chelation or with ADAM17-blockade, postulating a therapeutic strategy for SAH patients with iron overload.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADAM17 Protein / genetics
  • ADAM17 Protein / metabolism*
  • Adult
  • Aged
  • Antigens, CD / genetics
  • Antigens, CD / metabolism*
  • Antigens, Differentiation, Myelomonocytic / genetics
  • Antigens, Differentiation, Myelomonocytic / metabolism*
  • Case-Control Studies
  • Female
  • Hepatitis, Alcoholic / physiopathology*
  • Humans
  • Inflammation / etiology*
  • Inflammation / metabolism
  • Inflammation / pathology
  • Iron / metabolism*
  • Iron Overload / complications*
  • Iron Overload / metabolism
  • Iron Overload / pathology
  • Liver / metabolism
  • Liver / pathology
  • Macrophage Activation
  • Male
  • Middle Aged
  • Oxidative Stress
  • Prospective Studies
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / metabolism*
  • Tumor Necrosis Factor-alpha / metabolism
  • Young Adult

Substances

  • Antigens, CD
  • Antigens, Differentiation, Myelomonocytic
  • CD163 antigen
  • Receptors, Cell Surface
  • Tumor Necrosis Factor-alpha
  • Iron
  • ADAM17 Protein
  • ADAM17 protein, human

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