p38MAPK, ERK and PI3K signaling pathways are involved in C5a-primed neutrophils for ANCA-mediated activation

PLoS One. 2012;7(5):e38317. doi: 10.1371/journal.pone.0038317. Epub 2012 May 31.

Abstract

Background: The complement system is one of the important contributing factors in the development of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). C5a and the neutrophil C5a receptor play a central role in antineutrophil cytoplasmic antibody (ANCA)-mediated neutrophil recruitment and activation. The current study further investigated the signaling pathways of C5a-mediated priming of human neutrophils for ANCA-induced neutrophil activation.

Methodology/principal findings: The effects of the p38 mitogen-activated protein kinase (p38MAPK) inhibitor (SB202190), extracellular signal-regulated kinase (ERK) inhibitor (PD98059), c-Jun N-terminal kinase (JNK) inhibitor (6o) and phosphoinositol 3-kinase (PI3K) inhibitor (LY294002) were tested on respiratory burst and degranulation of C5a-primed neutrophils activated with ANCA, as well as on C5a-induced increase in expression of membrane-bound PR3 (mPR3) on neutrophils. For C5a-primed neutrophils for MPO-ANCA-induced respiratory burst, the mean fluorescence intensity (MFI) value was 254.8±67.1, which decreased to 203.6±60.3, 204.4±36.7, 202.4±49.9 and 188±47.9 upon pre-incubation with SB202190, PD98059, LY294002 and the mixture of above-mentioned three inhibitors (compared with that without inhibitors, P<0.01, P<0.05, P<0.01 and P<0.05), respectively. For PR3-ANCA-positive IgG, the MFI value increased in C5a-primed neutrophils, which decreased upon pre-incubation with above-mentioned inhibitors. The lactoferrin concentration increased in C5a-primed neutrophils induced by MPO or PR3-ANCA-positive IgG supernatant and decreased upon pre-incubation with above-mentioned three inhibitors. mPR3 expression increased from 923.3±182.4 in untreated cells to 1278.3±299.3 after C5a treatment and decreased to 1069.9±188.9, 1100±238.2, 1092.3±231.8 and 1053.9±200.3 by SB202190, PD98059, LY294002 and the mixture of above-mentioned three inhibitors (compared with that without inhibitors, P<0.01, P<0.05, P<0.01 and P<0.01), respectively.

Conclusions/significance: Activation of p38MAPK, ERK and PI3K are important steps in the translocation of ANCA antigens and C5a-induced activation of neutrophils by ANCA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Antineutrophil Cytoplasmic / immunology*
  • Antibodies, Antineutrophil Cytoplasmic / metabolism
  • Cell Degranulation / drug effects
  • Cell Degranulation / immunology
  • Cell Membrane / metabolism
  • Complement C5a / immunology*
  • Complement C5a / metabolism
  • Enzyme Inhibitors / pharmacology
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Myeloblastin / metabolism
  • Neutrophil Activation / drug effects
  • Neutrophil Activation / immunology*
  • Neutrophils / drug effects
  • Neutrophils / enzymology*
  • Neutrophils / immunology*
  • Peroxidase / metabolism
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphorylation
  • Protein Transport / drug effects
  • Proto-Oncogene Proteins c-akt / metabolism
  • Respiratory Burst / drug effects
  • Respiratory Burst / immunology
  • Signal Transduction*
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • Antibodies, Antineutrophil Cytoplasmic
  • Enzyme Inhibitors
  • Complement C5a
  • Peroxidase
  • Phosphatidylinositol 3-Kinases
  • Proto-Oncogene Proteins c-akt
  • Extracellular Signal-Regulated MAP Kinases
  • p38 Mitogen-Activated Protein Kinases
  • Myeloblastin