CONICET | Buscador de Institutos y Recursos Humanos

Parkinson?s disease (PD) is a neurodegenerativedisease characterized by the progressive loss of dopaminergic neurons (DAn) ofthe nigrostriatal system. Studies in animal models of PD have providedproof of concept that transplantation of DA precursors can relieve parkinsoniansymptoms. However, a major limiting factor of this strategy is the poorsurvival rate of grafted DAn. This could be due to host inflammatory response,among other factors. Our previous results demonstrated a host primary response relatedto the graft of human dopaminergic precursors (DA14), with an increase ofhost-MHCII positive cells. Expression of tumor necrosis factor-alpha (TNF-alpha)was also detected on host-ED1 positive cells. We aim to study the impact of thepro-inflammatory environment on DA14 cells and the effect of a TNF-alpha inhibitorin an in vitro approach. DA14 cells were exposed to conditioned media (CM) frombasal or activated BV2 microglial cells during 4 days. A significant increasein cell death was observed by fluorescence microscopy after Hoechst staining inDA14 cultures exposed with CM from activated microglia (p<0.05). This resultwas in accordance to a decrease in the number of Tyrosine hydroxylase (TH)positive cells detected by immunofluorescence (p<0.01). Neurite lengthmeasurement was performed to evaluate the differentiation process. A decreasein neurite length of TH positive cells was detected in DA14 cultures incubated withCM from activated microglia (p<0.05). In order to study the relevance ofTNF-alpha, DA14 cells were co-incubated with CM from basal or activated BV2cells and the TNF-alpha inhibitor, Etanercept. Inhibition of TNF-alpha was ableto avoid morphological alterations (p<0.05) and diminution of DA cells (p<0.05).Our results suggest that the pro-inflammatory microenvironment has a negativeimpact on survival and differentiation of DA14 cells. TNF-alpha inhibitioncould be an interesting strategy in order to improve survival of DA precursors.