Autophagy down regulates pro-inflammatory mediators in microglial cells and rescues alfa-synuclein induced neuronal cell death

KRISTAKIS N; CELEJ MS; PERALTA RAMOS J; IRIBARREN P; FLOREY O; ARROYO DS; SCHWAP Y; GALLEA JI; BUSSI C

Congreso; AVH-Kolleg, Current Advances on Neurodegeneration: form Molecular Biology to Translational Medicine; 2017

The autophagy pathway plays acrucial role in neurodegenerative diseases, although the precise mechanisms underlying these processes are poorlyunderstood and litle is known about the effects of the autophagic process and its regulation inmicroglial cells (MC). The aim of this study was to evaluate the effects of autophagy on the production ofpro-inflammatory mediators by alpha synuclein (α-syn) stimulated MC, and onneuronal viability in a co-culture model. In addition, we studied the autophagy dynamics in MC after α-syn stimulation.We found that autophagy induction in MC before exogenous α-syn stimulation downregulatedIL1β, IL-6, TNF-α and NO production. In addition, it also reduced the phosphorylation of p38and ERK1/2 MAPKs, which was required for microglial NO production. Besides, we observed inMC/N2A co-cultures that NO production by MC was necessary for neuronal cell death. Moreover, theinduction of autophagy in MC decreased mRNA iNOS levels and it promoted neuronal cell survival afterα-syn stimulation. Furthermore, we showed by time-lapse experiments with BV2 GFP-LC3 microglialcells that the autophagic protein LC3 it is atracted by lysosomes containing α-syn fibrils and wedemonstrated by live CLEM imaging that α-syn is targeted by autophagic vesicles. On the other hand,autophagy inhibition led to MC death after α-syn stimulation, indicating a protective role forautophagy during this process. Taken together, our results provide new evidence about the regulation ofthe inflammatory response by the autophagypathway in MC and its role as cell fate modulator.