Nutrient restriction regulates autophagy and amyloid beta content in astrocytes in vitro

GREGOSA A; BENTIVEGNA M; VINUESA A; POMILIO C; PRESA J; BELLOTTO M; GONZALEZ PEREZ N; SARAVIA F; BEAUQUIS J

Buenos Aires

Congreso; Congreso de la Sociedad Argentina de Investigación en Neurociencias; 2022

Sociedad Argentina de Investigación en Neurociencias

Previously, we evaluated the effects of a periodic dietary restriction protocol in a model offamilial Alzheimer's disease (AD) the PDAPP-J20 transgenic mouse. We observed areduction in hippocampal amyloid load and in glial reactivity, with lower levels ofproinflammatory markers as s100b and IL1b after dietary restriction. Also, we describedincreased adult neurogenesis associated with improved cognition in PDAPP-J20 mice underdietary restriction. LC3 and p62 autophagy markers were increased in astrocytes aroundamyloid plaques, possibly due to a blocked autophagy.Our objective is to understand how amyloid-beta (AB) affects the autophagic flux andwhether it is modulated by nutrient restriction (NR) in astrocytes in vitro. We hypothesizedthat AB could block autophagy and that NR would prevent it.We evaluated a NR protocol on astrocytes from the C6 line. Fibrillar AB 1-42 was used at0,5 uM (fAB). NR consisted in a reduction of fetal bovine serum (FBS) concentration to 2%(vs. control medium: RPMI + 10% FBS) for 6 h. Then, cells were incubated with fAB for 2, 6or 24 h. We performed a double immunofluorescence against AB (4G8) and LC3(autophagosome marker) and evaluated the area fraction for 40 cells per treatment, with theImageJ software.Exposure to fAB for 2 h was associated with increased LC3 after bafilomycin treatment, aninhibitor of autophagosome-lysosome fusion, indicating functional autophagy (fAB NR vs fABNR BAF, p