Neuroprotective potentials of neurotrophin rich olfactory ensheathing cell's conditioned media against 6OHDA-induced oxidative damage

Abstract

On the basis of recent reports, we propose that impaired neurotrophin signaling (PI3k/Akt), low antioxidant levels, and generation of reactive oxygen species (ROS) conjointly participate in the progressive events responsible for the dopaminergic cell loss in Parkinson's disease (PD). In the present study we tried to target these deficits collectively through multiple neurotrophic factors (NTFs) support in the form of Olfactory Ensheathing Cell's Conditioned Media (OEC CM) using human SH-SY5Y neuroblastoma cell line exposed to 6 hydroxydopamine (6OHDA). 6OHDA exposure induced, oxidative stress-mediated apoptotic cell death viz. enhanced ROS generation, diffused cytosolic cytochrome c (cyt c), impaired Bcl-2: Bax levels along with decrease in GSH content. These changes were accompanied by loss in Akt phosphorylation and TH levels in SH-SY5Y cells. OEC CM significantly checked apoptotic cell death by preserving pAkt levels which coincided with enhanced GSH and suppressed oxidative injury. Functional integrity of OEC CM supported cells was evident by maintained tyrosine hydroxylase (TH) expression. Intercepting Akt signaling by specific inhibitor LY294002 blocked the protective effect. Taken together our findings provide important evidence that the key to protective effect of multiple NTF support via OEC CM is enhanced Akt survival signaling which promotes antioxidant defense leading to suppression of oxidative damage.