Ibuprofen suppresses interleukin-1β induction of pro-amyloidogenic α1-antichymotrypsin to ameliorate β-amyloid (Aβ) pathology in Alzheimer's models

Epidemiological and basic research suggests that nonsteroidal anti-inflammatory drugs ( NSAIDs) should protect against the most common forms of Alzheimer's disease (AD). Ibuprofen reduces amyloid (A beta) pathology in some transgenic models, but the precise mechanisms remain unclear. Although some reports show select NSAIDs inhibit amyloid production in vitro, the possibility that in vivo suppression of amyloid pathology occurs independent of A beta production has not been ruled out. We show that ibuprofen reduced A beta brain levels in rats from exogenously infused A beta in the absence of altered A beta production. To determine whether ibuprofen inhibits pro-amyloidogenic factors, APPsw (Tg2576) mice were treated with ibuprofen for 6 months, and expression levels of the A beta and inflammation-related molecules alpha(1) antichymotrypsin (ACT), apoE, BACE1, and peroxisome proliferator-activated receptor gamma) (PPAR gamma) were measured. Among these, ACT, a factor whose overexpression accelerates amyloid pathology, was reduced by ibuprofen both in vivo and in vitro. IL-1 beta, which was reduced in our animals by ibuprofen, induced mouse ACT in vitro. While some NSAIDs may inhibit A beta 42 production, these observations suggest that ibuprofen reduction of A beta pathology may not be mediated by altered A beta 42 production. We present evidence supporting the hypothesis that ibuprofen-dependent amyloid reduction is mediated by inhibition of an alternate pathway (IL-1 beta and its downstream target ACT).