Copper induces oxidative stress and apoptosis of hippocampal neuron via pCREB/BDNF/ and Nrf2/HO-1/NQO1 pathway.

Disordered copper metabolism has been suggested to occur to several neurological conditions, including Alzheimer's disease and Parkinson's disease. However, the underlying mechanism was still unclear. This might link to copper-induced hippocampal neuronal apoptosis and decrease in neurons viability. Our vitro experiment showed copper exposure induced oxidative stress and promoted apoptosis of HT22 murine hippocampal neuronal cell. Mechanistically, we found copper, on the one hand, prevented phosphorylation of cAMP response element binding protein (CREB) to decrease expression its downstream target protein Brain-derived neurotrophic factor (BDNF), and to decrease mitochondrial membrane potential and Bcl-2/Bax ratio; on the other hand, copper-induced reactive oxygen species (ROS), promoted lipid peroxidation, reduced antioxidant enzyme activity of GSH-Px. Copper-induced oxidative damage further decreased the phosphorylation of CREB, decreased expression of Bcl-2, enhanced expression of Bax, and accelerated the dissociation of keap1-Nrf2 complex, promoted the nuclear translocation of Nrf2, stimulate the expression of antioxidant molecules HO-1 and NQO1. In conclusion, we found copper inhibited pCREB/BDNF signaling pathway by prevent CREB from phosphorylation, further found that oxidative damage not only inhibited neuroprotective signaling pathways and induced apoptosis, but activated antioxidant protection signals Nrf2/HO-1/NQO1 signaling pathway.