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Very low density lipoprotein potentiates tumor necrosis factor-alpha expression in macrophages.

Author

Summary, in English

High levels of the triacylglycerol-rich lipoproteins, very low density lipoprotein (VLDL) and intermediate density lipoprotein (IDL) have been identified as independent risk factors for coronary heart disease, and inflammation is thought to contribute to atherosclerosis and its complications. To understand how dyslipidemia promotes inflammation, we have characterised the effects of VLDL treatment on production of tumor necrosis factor-α (TNF) by human monocyte-derived macrophages. VLDL strongly potentiated lipopolysaccharide (LPS)-induced expression of TNF mRNA and secretion of TNF protein. VLDL activated mitogen-activated protein kinase-ERK kinase 1/2 (MEK1/2), and potentiated LPS-induced MEK1/2 activation. The MEK1/2 inhibitor U0126 strongly diminished TNF expression, indicating that MEK1/2 plays a central role in the regulation of TNF expression. VLDL did not activate transcription factors NF-κB and PPAR-γ, but it activated AP-1 at least as potently as LPS, and potentiated LPS-induced activation of AP-1. The inhibitor U0126 completely prevented this potentiation. Inhibition of AP-1 by decoy oligonucleotides abolished potentiation of TNF secretion by VLDL. In conclusion, VLDL treatment potentiates TNF expression in macrophages by activation of MEK1/2 and AP-1. These findings suggest that triacylglycerol-rich lipoproteins are involved in inflammatory processes associated with atherosclerosis.

Publishing year

2005

Language

English

Pages

247-254

Publication/Series

Atherosclerosis

Volume

179

Issue

2

Document type

Journal article

Publisher

Elsevier

Topic

  • Cardiac and Cardiovascular Systems

Keywords

  • Atherosclerosis
  • Inflammation
  • Activator protein-1
  • Very low density lipoprotein
  • Tumor necrosis factor

Status

Published

Research group

  • Cardiovascular Research - Immunity and Atherosclerosis

ISBN/ISSN/Other

  • ISSN: 1879-1484