Regulation of secretogranin II mRNA in rat neuronal cultures.
The regulation of SgII mRNA expression was investigated in primary cultures of neurons prepared from the hypothalamus and brainstem of 1-day-old rats. The administration of forskolin (FSK) resulted in a time- and dose-dependent increase in SgII mRNA expression, a 9-fold effect within 6 h being achieved with 10 microM FSK, which maximally increased cellular cAMP levels. SgII mRNA levels remained elevated for 24 h. Activation of protein kinase C with 100 nM phorbol 12-myristate 13-acetate (PMA) also increased SgII mRNA expression, although induction with PMA was slower and more moderate (3.8-fold above control after 24 h). Neither 10 microM 1,9-dideoxyforskolin nor 100 nM 4 alpha-phorbol 12,13-didecanoate, inactive analogues of FSK and PMA respectively, had an effect on SgII mRNA. Depolarization of neuronal cultures with 50 mM KCl had a small and variable effect on SgII mRNA levels (1.8-fold above control) in neuronal cultures and did not influence induction with FSK. To investigate whether neuron-like regulation of SgII mRNA expression could be reproduced in PC12 cells, PC12 cells were treated with 100 nM nerve growth factor (NGF) for 7 days prior to challenge with FSK or PMA. Whereas NGF alone modestly increased SgII mRNA expression in PC12 cells (1.8-fold above control), it did not uncover a stimulatory effect of FSK or PMA. These studies indicate that SgII mRNA expression is enhanced by an increase in cellular cAMP and activation of protein kinase C in primary cultures of neurons and emphasize that SgII mRNA is regulated in a cell-specific manner.
Scammell
J G
JG
Department of Pharmacology, University of South Alabama College of Medicine, Mobile 36688, USA.
Sumners
C
C
Reutter
M A
MA
Valentine
D L
DL
Jones
L C
LC
D000818:Animals; D000831:Animals, Newborn; D015152:Blotting, Northern; D001933:Brain Stem / Q000378:metabolism*; D002478:Cells, Cultured; D002864:Chromogranins; D005576:Colforsin / Q000031:analogs & derivatives / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D007031:Hypothalamus / Q000378:metabolism*; D007700:Kinetics; D009414:Nerve Growth Factors / Q000494:pharmacology; D009474:Neurons / Q000378:metabolism*; D016716:PC12 Cells; D011189:Potassium Chloride / Q000494:pharmacology; D014176:Protein Biosynthesis; D011493:Protein Kinase C / Q000378:metabolism; D011506:Proteins; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors
D002864:Chromogranins; D009414:Nerve Growth Factors; D011506:Proteins; D012333:RNA, Messenger; D005576:Colforsin; D011189:Potassium Chloride; D000242:Cyclic AMP; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate