Tumor necrosis factor downregulates an endothelial nitric oxide synthase mRNA by shortening its half-life

Masao Yoshizumi, Mark A. Perrella, John C. Burnett, Mu En Lee

Research output: Contribution to journalArticle

661 Scopus citations

Abstract

Nitric oxide (NO), which accounts for the biological properties of endothelium-derived relaxing factor, is generated by NO synthase (NOS). The vascular endothelium contains two types of NOS: one is constitutively expressed (cNOS), and the other is inducible. Endothelium-mediated vasorelaxation is impaired in atherosclerotic vessels. To determine whether tumor necrosis factor (TNF)-α, which is commonly found in atherosclerotic lesions, has an effect on NOS message, we measured cNOS mRNA levels in TNF-treated human umbilical vein endothelial cells (HUVECs) by RNA blot analysis with a cNOS cDNA probe. TNF-α markedly reduced cNOS mRNA levels in HUVECs in a dose- and time-dependent manner. In response to 3 ng/mL TNF-α, cNOS mRNA levels began to decrease at 4 hours and diminished to only 5% of control levels at 24 hours. As little as 0.1 ng/mL TNF-α reduced cNOS mRNA levels by 50%. This reduction in cNOS message in response to TNF-α depended on protein synthesis as it was blocked by cycloheximide. In nuclear runoff experiments, TNF-α did not change the rate of cNOS gene transcription. cNOS mRNA is very stable under basal conditions, with a half-life of 48 hours; however, treatment with TNF-α shortened this half-life to 3 hours. TNF-α thus appears to decrease cNOS mRNA levels by increasing the rate of mRNA degradation. TNF-induced reductions in cNOS mRNA levels may have an important effect on impaired endothelium-mediated vasorelaxation in atherosclerosis.

Original languageEnglish (US)
Pages (from-to)205-209
Number of pages5
JournalCirculation research
Volume73
Issue number1
DOIs
StatePublished - Jul 1993

Keywords

  • Atherosclerosis
  • Endothelium
  • Nitric oxide synthase
  • Transcriptional regulation
  • Tumor necrosis factor

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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