Insulin-like growth factor-1 inhibits STS-induced cell death and increases functional recovery of in vitro differentiated neurons.
NG108-15 cells differentiate into neurons by 1 mM sodium butyrate (NaB) treatment. Differentiated cells resulted more resistant to staurosporine (STS) than proliferating cells. In particular, STS treatment decreased Bcl-2 and Bcl-x(L) content in mitochondria of proliferating cells, but not in mitochondria of differentiated cells. Bad was phosphorylated and downregulated only in differentiated cells. Bax accumulated in the mitochondria of proliferating but not differentiated cells. Mitochondrial release of cytochrome c was observed in proliferating cells, whereas mitochondria of differentiated cells retained cytochrome c. Proliferating cells treated with STS accumulated Endo G and AIF in the nucleus. By contrast, differentiated cells did not show such nuclear accumulation. Treatment of differentiated cells with Insulin-like Growth Factor-1 (IGF-1) and STS resulted in a 17.1% increase of cell viability. The survival role of IGF-1 was demonstrated by treating differentiated cells with an anti-IGF-1 neutralizing antibody. Such treatment significantly increased STS-induced cell death. Electrophysiology studies showed that in STS-treated cells membrane potential oscillations were reduced in amplitude and did not give rise to spontaneous action potentials (APs). However, the percentage of cells yielding overshooting APs returned to control values after STS removal. It is concluded that neuronal differentiation of NG108-15 cells induces resistance to apoptotic cell death and that IGF-1 plays a central role in sustaining this mechanism.
Pucci
Bruna
B
Department of Cellular and Molecular Pathology, IRCCS San Raffaele Pisana, Rome, Italy. bruna.pucci@sanraffaele.it
Bertani
Francesca Romana
FR
Indelicato
Manuela
M
Sale
Patrizio
P
Lococo
Emanuela
E
Grassi
Francesca
F
Pagani
Francesca
F
Colafrancesco
Valeria
V
Morgante
Emanuela
E
Tafani
Marco
M
Fini
Massimo
M
Russo
Matteo A
MA
D000818:Animals; D017209:Apoptosis; D051033:Apoptosis Inducing Factor / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D004594:Electrophysiology; D004706:Endodeoxyribonucleases / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D009474:Neurons / Q000166:cytology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D019311:Staurosporine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D051025:bcl-Associated Death Protein / Q000378:metabolism; D051020:bcl-X Protein / Q000378:metabolism
D051033:Apoptosis Inducing Factor; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein; D007334:Insulin-Like Growth Factor I; D004706:Endodeoxyribonucleases; C052391:endonuclease G; D019311:Staurosporine