Overexpression of alpha7 nicotinic acetylcholine receptor prevents G1-arrest and DNA fragmentation in PC12 cells after hypoxia

We investigated the neuroprotective function of alpha7 nicotinic acetylcholine receptor (alpha7nAChR) after transient hypoxia (12 h) and reoxygenation (0-72 h), comparing rat pheochromocytoma (PC12) cells overexpressing FLAG-tagged alpha7nAChR (alpha7pCMV cells) and control PC12 cells (non-transfect...

Full description

Saved in:
Bibliographic Details
Published in:Journal of neurochemistry 2002-05, Vol.81 (3), p.497-505
Main Authors: Utsugisawa, Kimiaki, Nagane, Yuriko, Obara, Daiji, Tohgi, Hideo
Format: Article
Language:English
Subjects:
alpha7 Nicotinic Acetylcholine Receptor
Animals
Cell Cycle - physiology
Cell Hypoxia - physiology
Cytoprotection
DNA Fragmentation - drug effects
G1 Phase - physiology
Gene Expression
Genetic Vectors - genetics
Genetic Vectors - pharmacology
In Situ Nick-End Labeling
Nicotine - pharmacology
PC12 Cells
Pheochromocytoma - drug therapy
Pheochromocytoma - metabolism
Pheochromocytoma - pathology
Phosphorylation
Protein-Serine-Threonine Kinases
Proto-Oncogene Proteins - metabolism
Proto-Oncogene Proteins c-akt
Rats
Receptors, Nicotinic - drug effects
Receptors, Nicotinic - genetics
Receptors, Nicotinic - metabolism
Recombinant Fusion Proteins - genetics
Recombinant Fusion Proteins - metabolism
Recombinant Fusion Proteins - pharmacology
RNA, Messenger
Transfection
Up-Regulation - physiology
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We investigated the neuroprotective function of alpha7 nicotinic acetylcholine receptor (alpha7nAChR) after transient hypoxia (12 h) and reoxygenation (0-72 h), comparing rat pheochromocytoma (PC12) cells overexpressing FLAG-tagged alpha7nAChR (alpha7pCMV cells) and control PC12 cells (non-transfected or transfected with vector only) in medium with and without nicotine. Plasma membrane degradation in the early phase after hypoxia was inhibited in PC12 cells with nicotine, and more profoundly in alpha7pCMV cells with nicotine. Inhibition of DNA fragmentation in the late phase after hypoxia was most remarkable in alpha7pCMV cells with nicotine, but, surprisingly, it was more remarkable in alpha7pCMV cells without nicotine than in PC12 cells with nicotine. G1-arrest of the cell cycle, observed in control PC12 cells at 12 h after hypoxia, preceding DNA fragmentation, was not evident in alpha7pCMV cells, with or without nicotine. Furthermore, in alpha7pCMV cells with and without nicotine, the basal expression levels of total Akt were approximately 1.5-fold higher, and the up-regulation of Akt phosphorylated at Ser473 after hypoxia was strikingly enhanced, compared with control PC12 cells. These findings suggest that alpha7nAChR functions constitutively in PC12 cells, that its overexpression raises tolerance against G1-arrest and DNA fragmentation after hypoxia, and that it can be considered a candidate target for treatment against hypoxia-induced acute membrane degradation and delayed DNA fragmentation in neurons.
ISSN:0022-3042
1471-4159