Participation of PI3-kinase/Akt signalling in insulin stimulation of p34cdc2 activation in zebrafish oocyte: Phosphodiesterase 3 as a potential downstream target
- Authors
- Das, D., Khan, P.P., and Maitra, S.
- ID
- ZDB-PUB-130604-3
- Date
- 2013
- Source
- Molecular and Cellular Endocrinology 374(1-2): 46-55 (Journal)
- Registered Authors
- Keywords
- insulin signalling, PI3K, Akt, phosphodiesterase, oocyte maturation, zebrafish
- MeSH Terms
-
- 1-Methyl-3-isobutylxanthine/pharmacology
- Androstadienes/pharmacology
- Animals
- Chromones/pharmacology
- Cyclin-Dependent Kinases/genetics*
- Cyclin-Dependent Kinases/metabolism
- Female
- Gene Expression Regulation, Developmental/drug effects
- Hydroxyprogesterones/pharmacology
- Insulin/pharmacology*
- Isoenzymes/genetics
- Isoenzymes/metabolism
- Meiosis/drug effects
- Meiosis/genetics
- Morpholines/pharmacology
- Oocytes/cytology
- Oocytes/drug effects*
- Oocytes/metabolism
- Phosphatidylinositol 3-Kinase/genetics*
- Phosphatidylinositol 3-Kinase/metabolism
- Phosphodiesterase 3 Inhibitors/pharmacology
- Phosphoric Diester Hydrolases/genetics*
- Phosphoric Diester Hydrolases/metabolism
- Phosphorylation
- Proto-Oncogene Proteins c-akt/genetics*
- Proto-Oncogene Proteins c-akt/metabolism
- Quinolones/pharmacology
- Recombinant Proteins/pharmacology
- Signal Transduction/drug effects*
- Zebrafish/genetics
- Zebrafish/metabolism*
- PubMed
- 23623869 Full text @ Mol. Cell. Endocrinol.
Exposure of fully grown oocytes to growth factors (insulin/IGFs) initiates various signalling cascades that culminate to final stages of oocyte maturation. Regulation of signalling pathways during growth factor-induced meiosis resumption in fish is not well characterized. Here we studied the participation of PI3K/Akt signalling pathway during recombinant human insulin (rh-insulin)-induced meiotic maturation in zebrafish (Danio rerio) oocytes. Priming of defolliculated oocytes in vitro with rh-insulin promotes germinal vesicle breakdown (GVBD) in a dose- and time-dependent manner, an effect sensitive to translation but not transcription inhibition. More than 80% of the oocytes underwent GVBD due to 0.8 IU/ml rh-insulin within 10 h of incubation and the kinetics of p34cdc2 kinase activation corresponded well with GVBD data. PI3K inhibitors, wortmannin and LY294002 blocked insulin, but not 17α, 20β-DHP-induced GVBD. Immunoblot analyses of oocyte extract revealed that phospho-PI3K (p85α) was up regulated within 30–60 min of insulin stimulation followed by phospho-Akt (Ser473) at 60–120 min. Though PI3K/Akt phosphorylation was largely unaffected, pre-incubation with phosphodiesterase (PDE) inhibitors, IBMX and cilostamide, but not rolipram completely blocked rh-insulin-induced p34cdc2 activation and GVBD. These results suggest that PDE3 may be one potential downstream target to PI3K/Akt signalling necessary for rh-insulin-induced GVBD in zebrafish.