Leukocyte recruitment in the brain in sepsis: involvement of the annexin 1-FPR2/ALX anti-inflammatory system

FASEB J. 2012 Dec;26(12):4977-89. doi: 10.1096/fj.12-205971. Epub 2012 Sep 10.

Abstract

Unregulated inflammation underlies many diseases, including sepsis. Much interest lies in targeting anti-inflammatory mechanisms to develop new treatments. One such target is the anti-inflammatory protein annexin A1 (AnxA1) and its receptor, FPR2/ALX. Using intravital videomicroscopy, we investigated the role of AnxA1 and FPR2/ALX in a murine model of endotoxin-induced cerebral inflammation [intraperitoneal injection of lipopolysaccharide (LPS)]. An inflammatory response was confirmed by elevations in proinflammatory serum cytokines, increased cerebrovascular permeability, elevation in brain myeloperoxidase, and increased leukocyte rolling and adhesion in cerebral venules of wild-type (WT) mice, which were further exacerbated in AnxA1-null mice. mRNA expression of TLR2, TLR4, MyD-88, and Ly96 was also assessed. The AnxA1-mimetic peptide, AnxA1(Ac2-26) (100 μg/mouse, ∼33 μmol) mitigated LPS-induced leukocyte adhesion in WT and AnxA1-null animals without affecting leukocyte rolling, in comparison to saline control. AnxA1(Ac2-26) effects were attenuated by Boc2 (pan-FPR antagonist, 10 μg/mouse, ∼12 nmol), and by minocycline (2.25 mg/mouse, ∼6.3 nmol). The nonselective Fpr agonists, fMLP (6 μg/mouse, ∼17 nmol) and AnxA1(Ac2-26), and the Fpr2-selective agonist ATLa (5 μg/mouse, ∼11 nmol) were without effect in Fpr2/3(-/-) mice. In summary, our novel results demonstrate that the AnxA1/FPR2 system has an important role in effecting the resolution of cerebral inflammation in sepsis and may, therefore, provide a novel therapeutic target.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Annexin A1 / chemistry
  • Annexin A1 / genetics
  • Annexin A1 / metabolism*
  • Brain / blood supply
  • Brain / metabolism*
  • Brain / pathology
  • Cell Adhesion / drug effects
  • Cell Adhesion / genetics
  • Cerebrovascular Circulation / drug effects
  • Cytokines / blood
  • Gene Expression / drug effects
  • Inflammation / blood
  • Inflammation / chemically induced
  • Inflammation / metabolism*
  • Injections, Intraperitoneal
  • Leukocyte Rolling / drug effects
  • Leukocyte Rolling / genetics
  • Leukocytes / metabolism*
  • Leukocytes / pathology
  • Lipopolysaccharides / administration & dosage
  • Lipopolysaccharides / toxicity
  • Lymphocyte Antigen 96 / genetics
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Microscopy, Video
  • Minocycline / pharmacology
  • Oligopeptides / pharmacology
  • Peptide Fragments / pharmacology
  • Receptors, Formyl Peptide / antagonists & inhibitors
  • Receptors, Formyl Peptide / genetics
  • Receptors, Formyl Peptide / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sepsis / metabolism*
  • Toll-Like Receptors / genetics

Substances

  • Annexin A1
  • Cytokines
  • Lipopolysaccharides
  • Ly96 protein, mouse
  • Lymphocyte Antigen 96
  • Oligopeptides
  • Peptide Fragments
  • Receptors, Formyl Peptide
  • Toll-Like Receptors
  • annexin A1, mouse
  • formyl peptide receptor 2, mouse
  • butyloxycarbonyl-phenylalanyl-leucyl-phenylalanyl-leucyl-phenylalanine
  • Minocycline