N,N-disubstituted azines attenuate LPS-mediated neuroinflammation in microglia and neuronal apoptosis via inhibiting MAPK signaling pathways

Lalita Subedi, Oh Wook Kwon, Chaeho Pak, Goeun Lee, Kangwoo Lee, Hakwon Kim, Sun Yeou Kim

Activated microglia interact with astrocytes and neuronal cells to induce neuroinflammation, which can contribute to the pathogenesis and progression of Alzheimer's and Parkinson's disease. To identify the most effective anti-neuroinflammatory agent, we designed and synthesized a family of 13 new azine derivatives and investigated their anti-neuroinflammatory activities in LPS-activated BV-2 microglial cells. Out of 13 derivatives, compound 3 [4,4'-(1E,1'E,3E,3'E)-3,3'-(hydrazine-1,2-diylidene) bis-(prop-1-ene-1-yl-3-ylidene) bis-(2-methoxyphenol)] exhibited excellent anti-neuroinflammatory activities (IC50 = 12.47 µM), which protected neurons from microglia-mediated neurotoxicity. Specifically, the anti-neuroinflammatory effects of compound 3 inhibited MAPK signaling pathways through the inhibition of p38 and JNK mediated signaling and the production of pro-inflammatory cytokines, and inflammatory mediators. Additionally, compound 3 strongly exhibited neuroprotective effect by inhibiting LPS-mediated necrosis and apoptosis. Preliminary SAR analysis suggests that the presence of methoxyphenol and the substitution pattern within hydrazine may influence the anti-neuroinflammatory activity. FACS analysis also strongly supports the neuroprotective effect of compound 3. Based on our results, the compound 3 exhibited excellent anti-neuroinflammatory activity against LPS-activated microglia, which resulted in the inhibition of neuronal apoptosis and neuronal degeneration.