Anti-apoptotic actions of vasopressin in H32 neurons involve MAP kinase transactivation and Bad phosphorylation.
Vasopressin (VP) secreted within the brain modulates neuronal function acting as a neurotransmitter. Based on the observation that VP prevented serum deprivation-induced cell death in the neuronal cell line, H32, which expresses endogenous V1 receptors, we tested the hypothesis that VP has anti-apoptotic properties. Flow cytometry experiments showed that 10 nM VP prevented serum deprivation-induced cell death and annexin V binding. Serum deprivation increased caspase-3 activity in a time and serum concentration dependent manner, and VP prevented these effects through interaction with receptors of V1 subtype. The signaling pathways mediating the anti-apoptotic effect of VP involve mitogen activated protein (MAP) kinase and extracellular signal-regulated kinases (ERK), Ca(2+)/calmodulin dependent kinase (CaMK) and protein kinase C (PKC). Western blot analyses revealed time-dependent decreases of Bad phosphorylation and increases in cytosolic levels of cytochrome c following serum deprivation, effects which were prevented by 10 nM VP. These data demonstrate that activation of endogenous V1 VP receptors prevents serum deprivation-induced apoptosis, through phosphorylation-inactivation of the pro-apoptotic protein, Bad, and consequent decreases in cytosolic cytochrome c and caspase-3 activation. The data suggest that VP has anti-apoptotic activity in neurons and that VP may act as a neuroprotective agent in the brain.
Chen
Jun
J
Developmental Endocrinology Branch, National Institute of Child Health and Human Development, NIH, Bethesda MD 20892, USA.
Volpi
Simona
S
Aguilera
Greti
G
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D051017:Apoptosis Regulatory Proteins / Q000494:pharmacology / Q000502:physiology*; D002460:Cell Line; D002642:Chick Embryo; D004789:Enzyme Activation / Q000502:physiology; D020935:MAP Kinase Signaling System / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009474:Neurons / Q000201:enzymology / Q000378:metabolism*; D010766:Phosphorylation; D015533:Transcriptional Activation / Q000502:physiology*; D014667:Vasopressins / Q000494:pharmacology / Q000502:physiology*; D051025:bcl-Associated Death Protein / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology
D051017:Apoptosis Regulatory Proteins; D051025:bcl-Associated Death Protein; D014667:Vasopressins; D020928:Mitogen-Activated Protein Kinases