Impact of NMDA receptor activation on DNA damage in PC12 neuron-like cell cultures in the presence of β-amyloid peptides

OBJECTIVE: This study aimed to investigate the effect of low nanomolar concentrations of Aβ1–40 and Aβ25–35 on DNA double-strand breaks following NMDA activation of cells. MATERIALS AND METHODS: After incubating the differentiated PC12 cells with Aβ(25−35), Aβ(1−40) or Aβ(1−42) for 24 h, the culture was washed and stimulated for 15 min with NMDA. Then, tests were performed at four-time intervals from stimulation to assess the viability of the culture, the level of oxygen free radicals, and the γH2AX and pATM kinase. NMDAR1 expression was also evaluated by performing immunocytochemical staining. RESULTS: It was found that amyloid peptides in nanomolar concentrations reduce double-stranded DNA breaks after NMDA neuron activation. A slight antioxidant effect was also demonstrated when measured 120 min after NMDA cell activation. CONCLUSION: The NMDA stimulation of PC12 cells led to a rapid increase in the number of double-stranded DNA breaks in the cells and is assumed to be the initial step in IEG activation and LTP induction. The effect of Aβ on the reduction of double-strand breaks after NMDA cell stimulation indicates that at concentrations similar to physiological amyloid peptides, it may reduce the mobilization of the neuronal response to stimuli, leading to inhibition of LTP induction and decreasing synaptic plasticity in the early stages of Alzheimer’s disease.