Pinocembrin Protects Human Brain Microvascular Endothelial Cells against Fibrillar Amyloid-β (1−40)Injury by Suppressing the MAPK/NF-κB Inflammatory Pathways

Cerebrovascular accumulation of amyloid-β (Aβ) peptides in Alzheimer's disease (AD) may contribute to disease progression through Aβ-induced microvascular endothelial pathogenesis. Pinocembrin has been shown to have therapeutic effects in AD models. These effects correlate with preservation of microvascular function, but the effect on endothelial cells under Aβ-damaged conditions is unclear. The present study focuses on the in vitro protective effect of pinocembrin on fibrillar Aβ (1−40) (fAβ (1−40)) injured human brain microvascular endothelial cells (hBMECs) and explores potential mechanisms. The results demonstrate that fAβ (1−40)-induced cytotoxicity in hBMECs can be rescued by pinocembrin treatment. Pinocembrin increases cell viability, reduces the release of LDH, and relieves nuclear condensation. The mechanisms of this reversal from Aβ may be associated with the inhibition of inflammatory response, involving inhibition of MAPK activation, downregulation of phosphor-IKK level, relief of IκBα degradation, blockage of NF-κB p65 nuclear translocation, and reduction of the release of proinflammatory cytokines. Pinocembrin does not show obvious effects on regulating the redox imbalance after exposure to fAβ (1−40). Together, the suppression of MAPK and the NF-κB signaling pathways play a significant role in the anti-inflammation of pinocembrin in hBMECs subjected to fAβ (1−40). This may serve as a therapeutic agent for BMEC protection in Alzheimer's-related deficits.