Edaravone Attenuates the Proinflammatory Response in Amyloid-β-Treated Microglia by Inhibiting NLRP3 Inflammasome-Mediated IL-1β Secretion.

Background/aims: Microglial activation is an important pathological feature in the brains of patients with Alzheimer's disease (AD), and amyloid-β (Aβ) peptides play a crucial role in microglial activation. In addition, edaravone (EDA) was recently shown to suppress oxidative stress and proinflammatory cytokine production in APPswePS1dE9 (APP/PS1) mice. However, the mechanism by which EDA inhibits the Aβ-induced proinflammatory response in microglia is poorly understood.

Methods: The mitochondrial membrane potential (∆ψm) was evaluated using JC-1 staining. Intracellular reactive oxygen species (ROS) and mitochondrial ROS levels were detected using CM-H2DCFDA and MitoSOXTM Red, respectively. The levels of CD11b, NLRP3, pro-caspase-1 and manganese superoxide dismutase (SOD-2) were observed by western blotting, and the levels of interleukin-1beta (IL-1β) in culture supernatants were quantified using an ELISA kit.

Results: Aβ induced microglia activation and mitochondrial dysfunction. In addition, mitochondrial dysfunction was associated with ROS accumulation and activation of the NLRP3 inflammasome. Importantly, Aβ induced activation of the NLRP3 inflammasome, leading to caspase-1 activation and IL-1β release in microglia. Moreover, EDA obviously attenuated the depolarization of ∆ψm, reduced mitochondria-derived ROS production and increased SOD-2 activity, resulting in the suppression of NLRP3 inflammasome-mediated IL-1β secretion in Aβ-treated microglia.

Conclusion: EDA is a mitochondria-targeted antioxidant and exhibits anti-inflammatory effects on Aβ-treated microglia.