Involvement of multiple protein kinases in cPLA2 phosphorylation, arachidonic acid release, and cell death in in vivo and in vitro models of 1-methyl-4-phenylpyridinium-induced parkinsonism--the possible key role of PKG.
The study was aimed at investigating in vivo and in vitro the involvement of the cGMP/cGMP-dependent protein kinase (PKG) signaling pathway in MPP(+)-induced cytosolic phospholipase A(2) (cPLA(2)) activation of dopaminergic neurons. MPP(+) activated neuronal nitric oxide synthase (NOS)/soluble guanylyl cyclase/cGMP pathway in mouse midbrain and striatum, and in pheochromocytoma cell line 12 cells, and caused an upward shift in [Ca(2+)](i) level in the latter. The activation was accompanied by increases in total and phosphorylated cPLA(2), and increased arachidonic acid release. Effects of selective inhibitors [2-oxo-1,1,1-trifluoro-6,9-12,15-heneicosatetraene (AACOCF(3)), (E)-6-(bromomethylene)tetrahydro-3-(1-naphthalenyl)2h-pyran-2-one (BEL)] indicated the main impact of cPLA(2) on arachidonic acid release in pheochromocytoma cell line 12 cells. Treatment of the cells with the protein kinase inhibitors GF102610x, UO126, and KT5823, and with the nitric oxide synthase (NOS) inhibitor NNLA revealed the involvement of protein kinase C (PKC) and extracellular signal-regulated kinases 1 and 2 (ERK 1/2), with the possible key role of PKG, in cPLA(2) phosphorylation at Ser505. Inhibitors of cPLA(2) and PKG increased viability and reduced MPP(+)-induced apoptosis of the cells. Our results indicate that the neuronal NOS/cGMP/PKG pathway stimulates cPLA(2) phosphorylation at Ser505 by activating PKC and ERK1/2, and suggest that up-regulation of this pathway in experimental models of Parkinson's disease may mediate dopaminergic neuron degeneration and death through activation of cPLA(2).
Chalimoniuk
Malgorzata
M
Department of Cellular Signaling, Mossakowski Medical Research Center, Polish Academy of Sciences, Warsaw, Poland. mchalim@yahoo.com
Stolecka
Anna
A
Ziemińska
Elzbieta
E
Stepień
Adam
A
Langfort
Josef
J
Strosznajder
Joanna B
JB
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D020134:Catalytic Domain / Q000187:drug effects / Q000502:physiology; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D006152:Cyclic GMP / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D009410:Nerve Degeneration / Q000139:chemically induced / Q000201:enzymology* / Q000503:physiopathology; D052248:Nitric Oxide Synthase Type I / Q000187:drug effects / Q000378:metabolism; D016716:PC12 Cells; D020734:Parkinsonian Disorders / Q000201:enzymology* / Q000503:physiopathology; D054510:Phospholipases A2, Cytosolic / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013378:Substantia Nigra / Q000187:drug effects / Q000201:enzymology* / Q000503:physiopathology
D004791:Enzyme Inhibitors; D016718:Arachidonic Acid; D012694:Serine; D052248:Nitric Oxide Synthase Type I; D017869:Cyclic GMP-Dependent Protein Kinases; D011493:Protein Kinase C; D048049:Extracellular Signal-Regulated MAP Kinases; D054510:Phospholipases A2, Cytosolic; D006152:Cyclic GMP; D002118:Calcium