EFFECT OF THE PROINFLAMMATORY MICROENVIRONMENT ON HUMAN DOPAMINERGIC PRECURSORS SURVIVAL AND DIFFERENTIATION

FARIAS M; ZENG X; GRADASCHI V; FERRARI C; WENKER S; GARCIA C; PITOSSI F

CABA

Congreso; XX Jornadas Anuales de la Sociedad Argentina de Biología (SAB), XVII Jornadas de la Sociedad Uruguaya de Biociencias (SUB)- Segundas Jornadas Rioplatenses de Biología; 2018

SOCIEDAD ARGENTINA DE BIOLOGÍA (SAB)

Parkinson ´s Disease (PD) is a neurodegenerativedisorder characterized by the loss of dopaminergic (DA) neurons of thesubstantia nigra pars compacta. Successful transplantation ofdopamine-producing cells into the striatum has been shown in animal models andclinical trials. However, beneficial effects are constrained because of theremaining low number of DA neurons grafted. This could be due to hostinflammatory response, among other factors. Few reports have addressed theissue of inflammatory response effect on the survival and differentiation ofthe transplanted cells. We studied the host primary response related to thegraft of human DA precursors (DA14) invivo and the impact of proinflammatory factors on the viability anddifferentiation process of DA14 cells invitro.Ourin vivo results showeda significant increase (P<0.05) of host-MHCII and GFAP positive cells associatedto the human graft after 15 dayspost-transplant of DA14 cells into immunosuppressed rats. To study the effectof microglial activation, BV2 microglial cells were treated with LPS, and nitriteand TNF alpha production were determined. DA14 cells were exposed toconditioned media (CM) from basal and activated BV2 cells during 4 days and immunofluorescence(IF)for Tyrosine hydroxylase (TH) (DA neuronal marker) was performed at DA28 stage.Results from TH cell counting revealed that DA14 incubated with CM fromactivated microglia significantly decreased the number of DA neurons at DA28 (p<0.05).In order to study the short term effect of inflammatory environment, DA14 cellswere then exposed to CM from basal and activated BV2 cells during 4 days.After this treatment differentiation and survival assays were performed. TH cell counting suggested that CM from activated microglia during 4 dayssignificantly decreased the number of DA cells (p<0.05). During this period of time, Hoechststaining showed that the inflammatory factors from activatedmicroglia significantly increased celldeath (p<0.05). DA cellmorphology analysis was performed to evaluate the differentiation process. Decreasein the percentage of neuronal morphology-like cells was convoyed by neuritelength alterations after 4 days with CM activated microglia. In thisproinflammatory context, we also observed a negative modulation of two transcription factors involved indopaminergic differentiation: Foxa-2 and Nurr-1.Altogether our findings suggest that, microglialcells could play a fundamental role in the survival and differentiation of DAprecursors. The cellular and molecular mechanisms involved in these processesshould be considered and deeply analysed to improve cell replacement therapy.