The neuroprotective effect of Activin A and B: implication for neurodegenerative diseases

Activin is a member of the transforming growth factor-beta superfamily which comprises a growing list of multifunctional proteins that function as modulators of cell proliferation, differentiation, hormone secretion and neuronal survival. This study examined the neuroprotective effect of both Activin A and B in serum withdrawal and oxidative stress apoptotic cellular models and investigated the expression of pro- and anti-apoptotic proteins, which may account for the mechanism of Activin-induced neuroprotection. Here, we report that recombinant Activin A and B are neuroprotective against serum deprivation- and toxin- [either the parkinsonism-inducing neurotoxin, 6-hydroxydopamine (6-OHDA) or the peroxynitrite donor, 3-(4-morpholinyl) sydnonimine hydrochloride (SIN-1)] induced neuronal death in human SH-SY5Y neuroblastoma cells. Furthermore, we demonstrate for the first time that transient transfection with Activin beta A or beta B significantly protect SH-SY5Y and rat pheochromocytoma PC12 cells against serum withdrawal-induced apoptosis. This survival effect is mediated by the Bcl-2 family members and involves inhibition of caspase-3 activation; reduction of cleaved poly-ADP ribose polymerase and phosphorylated H2A.X protein levels and elevation of tyrosine hydroxylase expression. These results indicate that both Activin-A and -B share the potential to induce neuroprotective activity and thus may have positive impact on aging and neurodegenerative diseases to retard the accelerated rate of neuronal degeneration.