Fucoxanthin attenuates carbonyl stress and neuroinflammation by modulating MGO/RAGE/NF-κB axis in Aβ-induced models

Amyloid-β (Aβ) accumulation is a central pathological feature of Alzheimer's disease (AD) and a major driver of disease progression. Recent evidence suggests that carbonyl stress associated with Aβ plays a critical role in AD pathology by promoting neuroinflammation and neuronal damage. In particular, methylglyoxal (MGO), a highly reactive carbonyl compound, contributes to activation of the receptor for advanced glycation end products (RAGE) and NF-κB-dependent inflammatory signaling, leading to synaptic dysfunction. The present study investigated whether fucoxanthin, a marine-derived carotenoid, attenuates Aβ-induced carbonyl stress and inflammatory responses associated with MGO/RAGE/NF-κB-related signaling.

PC12 neuronal cells were pretreated with fucoxanthin (0.1-5 μM) and exposed to aggregated Aβ_25-35 (10 μM) to assess its effects on carbonyl stress-associated inflammatory signaling. In parallel, an Aβ_1-42 intracerebroventricular injection mouse model was used to validate the in vitro findings. Mice were orally administered fucoxanthin (100 or 200 mg/kg/day) for 15 days and assessed for serum MGO levels, hippocampal RAGE/NF-κB activation, microglial activation, and synaptic marker expression.

Fucoxanthin significantly reduced the expression of pro-inflammatory mediators, including COX-2, iNOS, IL-1β, and TNF-α in Aβ-exposed neuronal cells. This anti-inflammatory effect was associated with inhibition of NF-κB nuclear translocation and downregulation of RAGE expression. Consistent with these in vitro findings, fucoxanthin treatment in Aβ_1-42-injected mice alleviated systemic and hippocampal carbonyl stress, as evidenced by decreased serum MGO levels and suppression of hippocampal RAGE/NF-κB activation. These effects were accompanied by reduced microglial activation (Iba-1) across hippocampal subregions and significant restoration of both presynaptic and postsynaptic markers, indicating preservation of synaptic integrity.

These findings demonstrate the neuroprotective role of fucoxanthin in mitigating Aβ-induced carbonyl stress by targeting the MGO/RAGE/NF-κB axis, thereby suppressing neuroinflammation and preserving synaptic integrity in Aβ-induced cellular and mouse models. Fucoxanthin emerges as a promising pharmacological candidate targeting carbonyl stress-associated mechanisms in AD.