Activation of human inflammatory cells by secreted phospholipases A2

Biochim Biophys Acta. 2006 Nov;1761(11):1289-300. doi: 10.1016/j.bbalip.2006.07.003. Epub 2006 Jul 21.

Abstract

Secreted phospholipases A(2) (sPLA(2)s) are enzymes detected in serum and biological fluids of patients with various inflammatory, autoimmune and allergic disorders. Different isoforms of sPLA(2)s are expressed and released by human inflammatory cells, such as neutrophils, eosinophils, T cells, monocytes, macrophages and mast cells. sPLA(2)s generate arachidonic acid and lysophospholipids thus contributing to the production of bioactive lipid mediators in inflammatory cells. However, sPLA(2)s also activate human inflammatory cells by mechanisms unrelated to their enzymatic activity. Several human and non-human sPLA(2)s induce degranulation of mast cells, neutrophils and eosinophils and activate exocytosis in macrophages. In addition some, but not all, sPLA(2) isoforms promote cytokine and chemokine production from macrophages, neutrophils, eosinophils, monocytes and endothelial cells. These effects are primarily mediated by binding of sPLA(2)s to specific membrane targets (heparan sulfate proteoglycans, M-type, N-type or mannose receptors) expressed on effector cells. Thus, sPLA(2)s may play an important role in the initiation and amplification of inflammatory reactions by at least two mechanisms: production of lipid mediators and direct activation of inflammatory cells. Selective inhibitors of sPLA(2)-enzymatic activity and specific antagonists of sPLA(2) receptors are current being tested for pharmacological treatment of inflammatory and autoimmune diseases.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Autoimmune Diseases / enzymology
  • Autoimmune Diseases / immunology
  • Cell Degranulation / immunology
  • Exocytosis / immunology
  • Heparitin Sulfate / immunology
  • Heparitin Sulfate / metabolism
  • Humans
  • Inflammation / enzymology
  • Inflammation / immunology
  • Inflammation Mediators / immunology*
  • Inflammation Mediators / metabolism
  • Lectins, C-Type / immunology
  • Lectins, C-Type / metabolism
  • Leukocytes / enzymology
  • Leukocytes / immunology*
  • Macrophage Activation / immunology*
  • Mannose Receptor
  • Mannose-Binding Lectins / immunology
  • Mannose-Binding Lectins / metabolism
  • Phospholipases A / immunology*
  • Phospholipases A / metabolism
  • Protein Binding / immunology
  • Proteoglycans / immunology
  • Proteoglycans / metabolism
  • Receptors, Cell Surface / immunology
  • Receptors, Cell Surface / metabolism

Substances

  • Inflammation Mediators
  • Lectins, C-Type
  • Mannose Receptor
  • Mannose-Binding Lectins
  • Proteoglycans
  • Receptors, Cell Surface
  • Heparitin Sulfate
  • Phospholipases A