IGF-1 alleviates ox-LDL-induced inflammation via reducing HMGB1 release in HAECs

Acta Biochim Biophys Sin (Shanghai). 2012 Sep;44(9):746-51. doi: 10.1093/abbs/gms059. Epub 2012 Jul 10.

Abstract

Atherosclerosis, a multifactorial chronic inflammatory response, is closely associated with oxidatively modified low-density lipoprotein (ox-LDL). High-mobility group box 1 (HMGB1) is a DNA-binding protein, which upon release from cells exhibits potent inflammatory action. Insulin-like growth factor 1 (IGF-1) can elicit a repertoire of cellular responses including proliferation and anti-apoptosis. However, the role of IGF-1 in inflammation is still unclear. In the present study, we aimed to investigate the role of IGF-1 in inflammation and the underlying mechanism. Human aortic endothelial cells were stimulated by ox-LDL (50 μg/ml) to induce inflammation. The expression of intercellular adhesion molecule 1 (ICAM-1) was assessed by western blot analysis and immunofluorescence. The release of HMGB1 was determined by enzyme-linked immunosorbent assay. IGF-1 receptor (IGF-1R) expression was assessed by reverse transcription-polymerase chain reaction and western blot analysis. IGF-1R phosphorylation was determined by western blot analysis. Ox-LDL stimulation reduced IGF-1R mRNA and protein expression but increased HMGB1 release. IGF-1 treatment decreased ox-LDL-induced ICAM-1 expression potentially through reducing HMGB1 release, while picropodophyllin, an IGF-1R specific inhibitor, increased the inflammatory response. In conclusion, IGF-1 can alleviate ox-LDL-induced inflammation by reducing HMGB1 release, suggesting an unexpected beneficial role of IGF-1 in inflammatory disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aorta / cytology
  • Aorta / metabolism
  • Blotting, Western
  • Cell Line
  • Endothelial Cells / drug effects*
  • Endothelial Cells / metabolism
  • Gene Expression / drug effects
  • HMGB1 Protein / genetics
  • HMGB1 Protein / metabolism*
  • Humans
  • Inflammation / genetics
  • Inflammation / metabolism
  • Insulin-Like Growth Factor I / pharmacology*
  • Intercellular Adhesion Molecule-1 / genetics
  • Intercellular Adhesion Molecule-1 / metabolism
  • Lipoproteins, LDL / pharmacology*
  • Microscopy, Confocal
  • Oxidation-Reduction
  • Phosphorylation / drug effects
  • Podophyllotoxin / analogs & derivatives
  • Podophyllotoxin / pharmacology
  • RNA Interference
  • Receptor, IGF Type 1 / genetics
  • Receptor, IGF Type 1 / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Time Factors

Substances

  • HMGB1 Protein
  • Lipoproteins, LDL
  • oxidized low density lipoprotein
  • picropodophyllin
  • Intercellular Adhesion Molecule-1
  • Insulin-Like Growth Factor I
  • Receptor, IGF Type 1
  • Podophyllotoxin