Amyloid β-peptide activates nuclear factor-κB through an N-methyl-D-aspartate signaling pathway in cultured cerebellar cells

Amyloid β-peptide (Aβ) likely causes functional alterations in neurons well prior to their death. Nuclear factor-κB (NF-κB), a transcription factor that is known to play important roles in cell survival and apoptosis, has been shown to be modulated by Aβ in neurons and glia, but the mechanism is unknown. Because Aβ has also been shown to enhance activation of N-methyl-D-aspartate (NMDA) receptors, we investigated the role of NMDA receptor-mediated intracellular signaling pathways in Aβ-induced NF-κB activation in primary cultured rat cerebellar cells. Cells were treated with different concentrations of Aβ1-40 (1 or 2 μM) for different periods (6, 12, or 24 hr). MK-801 (NMDA antagonist), manumycin A and FTase inhibitor 1 (farnesyltransferase inhibitors), PP1 (Src-family tyrosine kinase inhibitor), PD98059 [mitogen-activated protein kinase (MAPK) inhibitor], and LY294002 [phosphatidylinositol 3-kinase (PI3-k) inhibitor] were added 20 min before Aβ treatment of the cells. Aβ induced a time- and concentration-dependent activation of NF-κB (1 μM, 12 hr); both p50/p65 and p50/p50 NF-κB dimers were involved. This activation was abolished by MK-801 and attenuated by manumycin A, FTase inhibitor 1, PP1, PD98059, and LY294002. Aβ at 1 μM increased the expression of inhibitory protein IκB, brain-derived neurotrophic factor, inducible nitric oxide synthase, tumor necrosis factor-α, and interleukin-1β as shown by RT-PCR assays. Collectively, these findings suggest that Aβ activates NF-κB by an NMDA-Src-Ras-like protein through MAPK and PI3-k pathways in cultured cerebellar cells. This pathway may mediate an adaptive, neuroprotective response to Aβ.