Extracellular signal-regulated kinase inhibition by statins inhibits neutrophil activation by ANCA.
BACKGROUND
3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) may modulate cellular inflammatory functions independent of serum cholesterol. We tested the hypothesis that statins decrease respiratory burst activity of human polymorphonuclear neutrophils (PMN) in response to anti-neutrophil cytoplasmic antibodies (ANCA).


METHODS
Neutrophils were isolated from healthy human volunteers, human immunoglobulins were isolated from patients with proteinase-3 (PR3)- and myeloperoxidase (MPO)-ANCA. Superoxide generation was measured by the ferricytochrome C assay and the nitro blue tetrazolium (NBT) test. ANCA antigen expression was measured by flow cytometry and phosphorylation of mitogen-activated protein kinase (MAPK) was assessed by Western blotting.


RESULTS
Cerivastatin and simvastatin inhibited respiratory burst activity to ANCA dose-dependently (1 to 25 micromol/L). Tumor necrosis factor-alpha (TNF-alpha)-primed neutrophils released 26.7 +/- 2.8 nmol O2-/0.75 x 106 PMN/45 min and 10 micromol/L simvastatin reduced this amount to 18.0 +/- 2.1 nmol. The inhibitory effect was confirmed by the NBT test. The respiratory burst decrease could not be reversed by 500 micromol/L mevalonic acid (MVA). In this assay, both statins also inhibited the response to human ANCA. PR3-ANCA resulted in 19.4 +/- 2.0 nmol O2- nmol. This amount was decreased to 6.0 +/- 1.2 nmol by preincubation with 10 micromol/L simvastatin (P < 0.01). For MPO-ANCA, the values were 22.6 +/- 2.8 nmol for controls versus 16.7 +/- 3.1 nmol with statin (P < 0.01). By FACS, simvastatin decreased TNF-alpha-mediated ANCA antigen translocation (from 219 +/- 33 to 180 +/- 35 MFI for PR3 and 24.0 +/- 2.4 to 18.3 +/- 1.1 for MPO). Finally, since p38 MAPK and ERK control TNF-alpha priming, we studied the effects of both statins on MAPK. Western blotting showed that statins inhibited TNF-alpha-induced ERK phosphorylation in a dose dependent fashion, but had no effect on p38.


CONCLUSIONS
These findings demonstrate that HMG-CoA reductase inhibitors decrease respiratory burst activity of human PMN in response to ANCA. This effect was independent of mevalonate, but involved inhibition of ERK activation during TNF-alpha priming. Our data suggest that HMG-CoA reductase inhibitors may help limit inflammatory responses.
Choi
Mira
M
HELIOS Klinkum-Berlin Franz Volhard Clinic and Max Delbrück Center for Molecular Medicine, Medical Faculty of the Charité, Humboldt University of Berlin, Berlin, Germany.
Rolle
Susanne
S
Rane
Madhavi
M
Haller
Hermann
H
Luft
Friedrich C
FC
Kettritz
Ralph
R
D019268:Antibodies, Antineutrophil Cytoplasmic / Q000494:pharmacology*; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D066298:In Vitro Techniques; D008798:Mevalonic Acid / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D018375:Neutrophil Activation / Q000187:drug effects* / Q000276:immunology*; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology / Q000276:immunology; D010766:Phosphorylation / Q000187:drug effects; D011725:Pyridines / Q000494:pharmacology*; D016897:Respiratory Burst / Q000187:drug effects / Q000276:immunology; D019821:Simvastatin / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
D019268:Antibodies, Antineutrophil Cytoplasmic; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D011725:Pyridines; D013481:Superoxides; D019821:Simvastatin; C086276:cerivastatin; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D008798:Mevalonic Acid