• Made available online as an Accepted Preprint 23 March 2009
  • Accepted Preprint first posted online on 23 March 2009

Regulation of urocortin I and its related peptide urocortin II by inflammatory and oxidative stresses in HL-1 cardiomyocytes

  1. Naoko Tajima2
  1. 1Department of Pharmacology2Division of Diabetes and Endocrinology, Department of Internal Medicine, the Jikei University School of Medicine, Tokyo 105-8461, Japan3Department of Biochemistry and Molecular Biology, Health Sciences Center, Louisiana State University, New Orleans, Louisiana 70112, USA
  1. (Correspondence should be addressed to K Ikeda; Email: ikedak{at}jikei.ac.jp)


Despite our knowledge on the regulation of urocortin (Ucn) I and its related peptides in the heart, the possible involvement of cardiovascular stress substances, such as cytokines or angiotensin II (Ang II), on this regulation remains to be fully elucidated. We therefore evaluated the potential role of cardiovascular stress substances on the regulation of the Ucn–corticotropin-releasing hormone (CRH) receptor system in HL-1 cardiomyocytes using a Ucn I-specific RIA, conventional reverse transcription-PCR (RT-PCR) and quantitative real-time RT-PCR. Ucn I mRNA levels were shown to be up-regulated by lipopolysaccarides (LPS), tumor necrosis factor-α (TNF-α), Ang II, H2O2, and pyrrolidinedithiocarbamate (PDTC). The LPS- and Ang II-induced increase in Ucn I mRNA levels was abolished by tempol. In addition, the secretion of Ucn I from HL-1 cardiomyocytes was stimulated by LPS and TNF-α. On the contrary, Ucn II mRNA was increased by TNF-α alone and Ang II with tempol, and the TNF-α-induced increase in Ucn II mRNA was abolished by erythromycin and PDTC. These results suggested that Ucn I mRNA may be up-regulated by oxidative stress, whereas Ucn II mRNA may be up-regulated by the activated nuclear factor-κB, i.e. inflammatory stress. CRH-R2 mRNA may be negatively regulated by the increase in expression of Ucn I and/or Ucn II mRNA. In conclusion, the Ucn–CRH receptor system may be regulated by two major forms of cardiac stresses, i.e. oxidative and inflammatory stress, and may play a critical role in cardiac stress adaptation in heart diseases.

  • Revision received 4 March 2009
  • Accepted 23 March 2009
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