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

GREGOSA, AMAL; BENTIVEGNA, MELISA; VINUESA, ÁNGELES; POMILIO, CARLOS; PRESA, JESSICA; MELINA BELLOTTO; NICOLÁS GABRIEL GONZÁLEZ PÉREZ; SARAVIA, FLAVIA; BEAUQUIS, JUAN

Belén

Congreso; 3rd FALAN Congress; 2022

FALAN

Previously, we evaluated the effects of a periodic dietary restriction protocol in a model of familial Alzheimer´s disease (AD), the PDAPP-J20 transgenic mouse. We observed a reduction in hippocampal amyloid load and in glial reactivity, with lower levels of proinflammatory markers as s100b and IL1b after dietary restriction. Also, we described increased adult neurogenesis associated with improved cognition in PDAPP-J20 mice under dietary restriction. LC3 and p62 autophagy markers were increased in astrocytes around amyloid plaques, possibly due to a blocked autophagy. Our objective is to understand how amyloid-beta (AB) affects the autophagic flux and whether it is modulated by nutrient restriction (NR) in astrocytes in vitro. We hypothesized that 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 at 0,5 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, 6 or 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 the ImageJ software. Exposure to fAB for 2 h was associated with increased LC3 after bafilomycin treatment, an inhibitor of autophagosome-lysosome fusion, indicating functional autophagy (fAB NR vs fAB NR BAF, p