Effects of copper overload on cholesterol synthesis and APP cleavage

ROSA DIANA; ASTIZ MARIANA; ZUBILLAGA MARLENE; ARNAL, NATHALIE

Córdoba

Congreso; XXXIV Reunión Anual SAN 2019; 2019

Sociedad Argentina de Neurociencias

Copper (Cu) is involved in the development of many neurodegenerative disorders. Brain cells depend entirely on cholesterol (Cho) in situ synthesis. It was demonstrated that high plasma Cu concentration is in line with rises in Cho levels (Armstrong et al., 2001; Arnal et al., 2013). Many works show increases in the transcription of genes related to Cho synthesis in human macrophages and in Jurkat cultured cells exposed to Cu (Svensson et al., 2003; Gutiérrez et al., 2013). The amyloid precursor protein (APP) is housed in Cho rafts. It has been proven that increases in Cho levels would favor the processing of APP towards the formation of Aβ peptides (Liu et al, 2009).The objective of this work was to evaluate if Cu overload could favour Cho synthesis in cultured neurons (SHSY5Y), inducing the processing of APP to the amyloidogenic pathway. Cu levels were evaluated by atomic absorption spectrophotometry. The synthesis of Cho was analyzed using radioactively labeled acetate by TLC. and Cho in plasma membrane Ficoll gradient. The protein levels of HMGCR and APP was evaluated in cellular homogenates and levels of Aβ peptides in culture medium by western blot. Finally, HMGCR expression was assessed by qPCR.Conclusions: Neuron cells exposed to Cu overload show increased levels of HMGCR. Higher levels of the novo synthesized, and membrane Cho were observed in Cu treated cells than in control ones. Finally, there were no changes in APP levels. Currently, we are analyzing the levels of Aβ.