| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Regular Articles |






From the Centre for Molecular Inflammation and Vascular Research, Mater Misericordiae Hospital, the Department of Medicine and Therapeutics,*Conway Institute of Biomolecular and Biomedical Research, and The Electron Microscopy Laboratory,
University College Dublin and Dublin Molecular Medicine Centre,
Dublin, Ireland; and the Department of Chemistry,
University of Southern California, Los Angeles, California
Lipoxins (LXs) are endogenously produced eicosanoids that inhibit neutrophil trafficking and stimulate nonphlogistic phagocytosis of apoptotic neutrophils by monocyte-derived macrophages. In this study we assessed the effect of LXs on cell ultrastructure and actin reorganization in human leukocytes and investigated the signaling events that subserve LX bioactivity in this context. LXA4 (10-9 mol/L), the stable synthetic analogues 15-(R/S)-methyl-LXA4 and 16-phenoxy-LXA4 (10-11 mol/L), but not the LX precursor 15-(S)-HETE, induced marked changes in ultrastructure and rearrangement of actin in monocytes and macrophages. In contrast, LXA4 did not modify actin distribution in neutrophils under basal conditions and after stimulation with leukotriene B4. Blockade of Rho kinases by the inhibitor Y-27632 prevented LXA4-triggered actin reorganization in macrophages. To investigate the role of the specific small GTPases in LX-induced actin rearrangement we used THP-1 cells differentiated to a macrophage-like phenotype. THP-1 cells stimulated with LXs, but not with 15-(S)-HETE, showed an increase in membrane-associated RhoA and Rac by immunoblotting. Additionally, a twofold increase in Rho activity was seen in response to LXA4. LX-induced actin rearrangement and RhoA activation were inhibited by the cell permeable cAMP analogue 8-Br-cAMP, whereas Rp-cAMP, an inhibitor of protein kinase A, mimicked the effect of LXA4. These data demonstrate that LXs stimulate RhoA- and Rac-dependent cytoskeleton reorganization, contributing to the potential role of LXs in the resolution of inflammation.
This article has been cited by other articles:
![]() |
R. S. Mishra, K. A. Carnevale, and M. K. Cathcart iPLA2{beta}: front and center in human monocyte chemotaxis to MCP-1 J. Exp. Med., February 18, 2008; 205(2): 347 - 359. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. D. John, V. Sahni, D. Mehet, J. F. Morris, H. C. Christian, M. Perretti, R. J. Flower, E. Solito, and J. C. Buckingham Formyl peptide receptors and the regulation of ACTH secretion: targets for annexin A1, lipoxins, and bacterial peptides FASEB J, April 1, 2007; 21(4): 1037 - 1046. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Chiang, C. N. Serhan, S.-E. Dahlen, J. M. Drazen, D. W. P. Hay, G. E. Rovati, T. Shimizu, T. Yokomizo, and C. Brink The Lipoxin Receptor ALX: Potent Ligand-Specific and Stereoselective Actions in Vivo Pharmacol. Rev., September 1, 2006; 58(3): 463 - 487. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Reville, J. K. Crean, S. Vivers, I. Dransfield, and C. Godson Lipoxin A4 Redistributes Myosin IIA and Cdc42 in Macrophages: Implications for Phagocytosis of Apoptotic Leukocytes J. Immunol., February 1, 2006; 176(3): 1878 - 1888. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. L. Simoes and I. M. Fierro Involvement of the Rho-Kinase/Myosin Light Chain Kinase Pathway on Human Monocyte Chemotaxis Induced by ATL-1, an Aspirin-Triggered Lipoxin A4 Synthetic Analog J. Immunol., August 1, 2005; 175(3): 1843 - 1850. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Maderna, S. Yona, M. Perretti, and C. Godson Modulation of Phagocytosis of Apoptotic Neutrophils by Supernatant from Dexamethasone-Treated Macrophages and Annexin-Derived Peptide Ac2-26 J. Immunol., March 15, 2005; 174(6): 3727 - 3733. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Fiorucci, J. L. Wallace, A. Mencarelli, E. Distrutti, G. Rizzo, S. Farneti, A. Morelli, J.-L. Tseng, B. Suramanyam, W. J. Guilford, et al. A {beta}-oxidation-resistant lipoxin A4 analog treats hapten-induced colitis by attenuating inflammation and immune dysfunction PNAS, November 2, 2004; 101(44): 15736 - 15741. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Ohira, G. Bannenberg, M. Arita, M. Takahashi, Q. Ge, T. E. Van Dyke, G. L. Stahl, C. N. Serhan, and J. A. Badwey A Stable Aspirin-Triggered Lipoxin A4 Analog Blocks Phosphorylation of Leukocyte-Specific Protein 1 in Human Neutrophils J. Immunol., August 1, 2004; 173(3): 2091 - 2098. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. McMahon and C. Godson Lipoxins: endogenous regulators of inflammation Am J Physiol Renal Physiol, February 1, 2004; 286(2): F189 - F201. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. O. Leonard, D. C. Cottell, C. Godson, H. R. Brady, and C. T. Taylor The Role of HIF-1{alpha} in Transcriptional Regulation of the Proximal Tubular Epithelial Cell Response to Hypoxia J. Biol. Chem., October 10, 2003; 278(41): 40296 - 40304. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Bonnans, B. Mainprice, P. Chanez, J. Bousquet, and V. Urbach Lipoxin A4 Stimulates a Cytosolic Ca2+ Increase in Human Bronchial Epithelium J. Biol. Chem., March 21, 2003; 278(13): 10879 - 10884. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Mitchell, G. Thomas, K. Harvey, D. Cottell, K. Reville, G. Berlasconi, N. A. Petasis, L. Erwig, A. J. Rees, J. Savill, et al. Lipoxins, Aspirin-Triggered Epi-Lipoxins, Lipoxin Stable Analogues, and the Resolution of Inflammation: Stimulation of Macrophage Phagocytosis of Apoptotic Neutrophils In Vivo J. Am. Soc. Nephrol., October 1, 2002; 13(10): 2497 - 2507. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |