INDUCTION OF AUTOPHAGY IN BV2 MICROGLIAL CELLS MODULATES PRO-INFLAMMATORY MEDIATORS LEVELS AND RESCUES BOTH LPS AND ALPHA-SYNUCLEIN-INDUCED NEURONAL CELL DEATH

BUSSI CLAUDIO; PERALTA-RAMOS JAVIER M; GAVIGLIO EMILIA A; ARROYO DANIELA S; GALLEA JI; CELEJ MS; IRIBARREN PABLO

Congreso; Joint IUPAB IUBMB advanced school on receptors and signaling; 2016

Autophagy is a fundamental cellular homeostatic mechanism, whereby cells autodigest parts of their cytoplasm for removal or turnover. Paradoxically, although autophagy is primarily a protective process for the cell, it can also play a role in cell death. Microglial cells (MC) are resident macrophages in the central nervous system (CNS) and have multiple functions, such as phagocytosis, production of growth factors and cytokines, and antigen presentation.The aim of this study was to evaluate the effects of autophagy on the production of pro-inflammatory mediators by BV2 MC, and on neuronal viability in a co-culture model. Autophagy was induced in MC before or after TLR or alpha-synuclein (α-syn) stimulation by rapamycin or trehalose and blocked by using 3-Methyladenine. Supernatants were isolated and analyzed by ELISA and Griess assay to determine cytokines and nitric oxide (NO) levels, respectively. Autophagic activity was followed by confocal microscopy and WB. Cell death was evaluated using AnnexinV/propidium iodide staining and subsequent flow cytometric analysis.Autophagy induction in BV2 cells before LPS or α-syn stimulation downregulated IL1β, IL-6, TNFα and NO production (p<0.01). In addition, we observed in BV2/N2A co-cultures stimulated with LPS or α-syn fibers that induction of autophagy in microglial cells rescued LPS and α-syn-induced neuronal cell death (p<0.05).Moreover, we wanted to determine if autophagy activity could regulate the phosphorylation status (p-) of p38 and ERK1/2, two MAPKs involved in cellular programs such as inflammation and cell death. We observed a reduction in both p-p38 and p-ERK1/2 levels after inducing autophagy in MC stimulated with α-syn fibers or LPS (p<0.05).Despite the increasing reports studying the effects of autophagy in the CNS, slightly emphasis is placed on MC. These results suggest that modulation of microglial cells by autophagy could be an important strategy in the context of neurodegenerative diseases.