title: Pathways of survival induced by NGF and extracellular ATP after growth factor deprivation.
abstract: In a previous work we demonstrated that extracellular adenosine-5'-triphosphate (ATP), acting on P2 receptors, exerts neuritogenic and trophic effects on the phaeochromocytoma PC12 cell line. These actions are comparable to those sustained by nerve growth factor (NGF) and involve several overlapping pathways. In this work, we describe some of the mechanisms recruited by ATP and NGF in maintaining PC12 cell survival after serum deprivation. We show that both ATP and NGF upregulate the expression of the stress-induced heat shock protein HSP70 and HSP90, whilst glucose-response protein GRP75 and GRP78 are not affected. In parallel with NGF, ATP prevents the cleavage and activation of caspase-2 and inhibits the release of cytochrome c from mitochondria into the cytoplasm. Finally, neither NGF, nor ATP directly modulate the expression of P2 receptors in the induction of cell survival. Our data contribute to dissect the biological mechanisms activated by extracellular purines exerting trophic actions and to establish that survival and neurite outgrowth lie on different mechanistic pathways.
authors.affiliation: Fondazione Santa Lucia, University of Rome Tor Vergata, Department of Neuroscience, Rome, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: D'Ambrosi
authors.forename: Barbara
authors.initials: B
authors.lastname: Murra
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Vacca
authors.forename: Cinzia
authors.initials: C
authors.lastname: Volonté
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D053143:Caspase 2; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects* / Q000502:physiology; D045304:Cytochromes c / Q000378:metabolism; D005110:Extracellular Space / Q000187:drug effects* / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D020932:Nerve Growth Factor / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects; D016716:PC12 Cells; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000187:drug effects / Q000378:metabolism; D044967:Serum / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D006360:Heat-Shock Proteins; D018048:Receptors, Purinergic P2; D000255:Adenosine Triphosphate; D045304:Cytochromes c; D020932:Nerve Growth Factor; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D053143:Caspase 2; D020169:Caspases