HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Published online before print February 23, 2005

This Article Full Text Full Text (PDF) All Versions of this Article: jlb.1204740v1 77/6/1018    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Pettersson, A. Articles by Karlsson, U. Search for Related Content PubMed PubMed Citation Articles by Pettersson, A. Articles by Karlsson, U.

(Journal of Leukocyte Biology. 2005;77:1018-1025.)
© 2005 by Society for Leukocyte Biology

Pro- and anti-inflammatory substances modulate expression of the leukotriene B₄ receptor, BLT1, in human monocytes

Annika Pettersson^*, Alan Sabirsh, Jesper Bristulf^*, Karin Kidd-Ljunggren, Bengt Ljungberg, Christer Owman^* and Ulf Karlsson^*,,1

^* Division of Molecular Neurobiology, Wallenberg Neuroscience Center, Lund University, and
Division of Infectious Diseases, Lund University Hospital, Sweden; and
Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden

¹Correspondence: Division of Molecular Neurobiology, Wallenberg Neuroscience Center, BMC A12, Lund University, 22184 Lund, Sweden. E-mail: Ulf.Karlsson{at}mphy.lu.se

The high-affinity leukotriene B₄ (LTB₄) receptor, BLT1, is a chemotactic receptor involved in inflammatory responses. In this study, we have explored the regulation of BLT1 expression in human monocytes by pro- and anti-inflammatory cytokines, lipopolysaccharide (LPS), and dexamethasone. We found that proinflammatory mediators, such as interferon- (IFN-), tumor necrosis factor-, and LPS, down-regulated expression, whereas the anti-inflammatory cytokine, interleukin-10, and dexamethasone up-regulated BLT1 mRNA expression. The effect of IFN- on BLT1 mRNA expression was rapidly detectable (<4 h) and concentration-dependent (1–50 ng/ml) and seems to be exerted through a block in transcriptional activity. Alterations in mRNA expression were accompanied by changes in BLT1 surface expression, and receptor down-modulation following IFN- stimulation resulted in a diminished chemotactic response to LTB₄. The regulation of BLT1 mRNA and receptor protein expression was similar to the regulation of the monocyte chemoattractant protein-1 chemokine receptor, CC chemokine recptor 2 (CCR2). Flow cytometric analysis of fresh peripheral blood cells revealed that classical (CD14⁺⁺CD16^–) monocytes express high levels of BLT1 and CCR2 and that both receptors are down-regulated on CD14⁺CD16⁺ monocytes. Apart from providing insight into the regulation of BLT1 in human monocytes, our results reveal a parallel expression and regulation of BLT1 and CCR2, which may help to understand monocyte trafficking during pathophysiological conditions.

Key Words: mononuclear phagocytes • LTB₄ • IFN- • inflammatory mediators

This article has been cited by other articles:

				A. Fortin, D. Harbour, M. Fernandes, P. Borgeat, and S. Bourgoin Differential expression of adenosine receptors in human neutrophils: up-regulation by specific Th1 cytokines and lipopolysaccharide J. Leukoc. Biol., March 1, 2006; 79(3): 574 - 585. [Abstract] [Full Text] [PDF]