Protein kinase C- and reactive oxygen species-dependent stimulation of intracellular cAMP in human eosinophils. The role of extracellular signal-regulated protein kinases.
Med Princ Pract
; 17(6): 468-74, 2008.
Article
in En
| MEDLINE
| ID: mdl-18836276
ABSTRACT
OBJECTIVE:
The objective of this study was to investigate the role of the extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) in the signalling pathway of the novel protein kinase C (PKC)- and reactive oxygen species (ROS)-dependent stimulation of intracellular adenosine 3',5'-cyclic monophosphate (cAMP) production in human eosinophils. MATERIALS ANDMETHODS:
Immunomagnetically purified human eosinophils were stimulated in vitro with a PKC activator, phorbol myristate acetate (PMA), and the cAMP response in the presence of a phosphodiesterase inhibitor, rolipram, was determined. The role of ERK1/2 phosphorylation was investigated using specific inhibitors and Western blot analysis.RESULTS:
The PMA-stimulated eosinophils responded with a profound increase in intracellular levels of cAMP that was dependent on both PKC and ROS, as confirmed by the use of specific inhibitors Ro 31-8220 for PKC and diphenyleneiodonium (DPI) for the ROS-generating enzyme NADPH oxidase. Pre-treatment of cells with the ERK1/2 inhibitor PD 98059, but not the p38-MAPK inhibitor SB203580, nor the PI3 kinase inhibitor, wortmannin, abolished the response. PMA treatment induced the phosphorylation of ERK1/2 with a time course that is consistent with a role in the cAMP response. The ERK1/2 phosphorylation was abolished by the ERK1/2 inhibitor PD 98059 and the PKC inhibitor Ro 31-8220, but not the NADPH oxidase inhibitor DPI.CONCLUSION:
These results reveal the involvement of ERK1/2 in the signalling mechanism of PMA-stimulated, PKC- and ROS-dependent stimulation of cAMP production in human eosinophils, and show that ERK1/2 phosphorylation is upstream of ROS production in the signalling pathway.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Protein Kinase C
/
Reactive Oxygen Species
/
Cyclic AMP
/
Extracellular Signal-Regulated MAP Kinases
/
Eosinophils
Limits:
Humans
Language:
En
Journal:
Med Princ Pract
Journal subject:
EDUCACAO
Year:
2008
Type:
Article
Affiliation country:
Kuwait