Activation of nuclear factor-kappa B by beta-amyloid peptides and interferon-gamma in murine microglia.
An increasing body of evidence suggests that amyloid-beta (A beta) peptides and microglia are crucially involved in the pathogenesis of Alzheimer's disease. In an effort to further elucidate the biological effects of A beta towards microglia, we investigated the ability of A beta peptides to activate nuclear factor (NF)-kappa B in the N9 murine microglial cell line. Co-stimulation of microglia with suboptimal concentrations of A beta(25-35) and 100 U/ml IFN gamma resulted in the detection of a specific NF-kappa B DNA-binding activity in nuclear extracts, as determined in gel mobility shift assays. This response required at least 120 min to be evident and supershift experiments revealed that the NF-kappa B complex contains both RelA and p50. Accordingly, immunoblot experiments showed that amongst NF-kappa B/Rel proteins, RelA and p50 are mobilized to the nucleus following microglial cell stimulation with A beta(25-35) plus IFN gamma. Higher concentrations of A beta(25-35) were effective by themselves in inducing NF-kappa B activation, both in the N9 microglial cell line and in rat primary microglia, as well as in human monocytes. For purposes of comparison, microglia were also stimulated with bacterial LPS, a known NF-kappa B inducer. As expected, LPS strongly induced the formation of two NF-kappa B DNA-binding activities, one of which was identified as RelA/p50. The LPS response was also more rapid, as it was already evident by 40 min and remained sustained for up to 3 h. Collectively, these findings indicate that NF-kappa B activation might constitute one of the mechanisms underlying the inducible expression of kappa B-dependent genes in microglia stimulated by A beta peptides and IFN gamma, or by LPS.
Bonaiuto
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C
Department of General Pathology, University of Verona, Italy.
McDonald
P P
PP
Rossi
F
F
Cassatella
M A
MA
D016229:Amyloid beta-Peptides / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D051379:Mice; D017628:Microglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D016328:NF-kappa B / Q000276:immunology / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology*; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D012680:Sensitivity and Specificity
D016229:Amyloid beta-Peptides; D016207:Cytokines; D004268:DNA-Binding Proteins; D016328:NF-kappa B; D010446:Peptide Fragments; C074636:amyloid beta-protein (25-35); D009569:Nitric Oxide; D007371:Interferon-gamma