Phenotype-based screening rediscovered benzopyran-embedded microtubule inhibitors as anti-neuroinflammatory agents by modulating the tubulin–p65 interaction

Neuroinflammation is one of the critical processes implicated in central nervous system (CNS) diseases. Therefore, alleviating neuroinflammation has been highlighted as a therapeutic strategy for treating CNS disorders. However, the complexity of neuroinflammatory processes and poor drug transport to the brain are considerable hurdles to the efficient control of neuroinflammation using small-molecule therapeutics. Thus, there is a significant demand for new chemical entities (NCEs) targeting neuroinflammation. Herein, we rediscovered benzopyran-embedded tubulin inhibitor 1 as an anti-neuroinflammatory agent via phenotype-based screening. A competitive photoaffinity labeling study revealed that compound 1 binds to tubulin at the colchicine-binding site. Structure–activity relationship analysis of 1 ’s analogs identified SB26019 as a lead compound with enhanced anti-neuroinflammatory efficacy. Mechanistic studies revealed that upregulation of the tubulin monomer was critical for the anti-neuroinflammatory activity of SB26019. We serendipitously found that the tubulin monomer recruits p65, inhibiting its translocation from the cytosol to the nucleus and blocking NF-κB-mediated inflammatory pathways. Further in vivo validation using a neuroinflammation mouse model demonstrated that SB26019 suppressed microglial activation by downregulating lba-1 and proinflammatory cytokines. Intraperitoneal administration of SB26019 showed its therapeutic potential as an NCE for successful anti-neuroinflammatory regulation. Along with the recent growing demands on tubulin modulators for treating various inflammatory diseases, our results suggest that colchicine-binding site-specific modulation of tubulins can be a potential strategy for preventing neuroinflammation and treating CNS diseases. Neurodegeneration: A new approach to reduce brain inflammation A screen for compounds that reduce inflammation in the brain has identified an effective compound with an unexpected mode of action, potentially opening a new therapeutic avenue for neurodegenerative diseases. Neuroinflammation contributes to the pathology of diseases like Alzheimer’s and Parkinson’s, but researchers have struggled to develop drugs targeting such inflammation. South Korean researchers led by Seung Bum Park of Seoul National University and Jongmin Park of Kangwon National University, Chuncheon, screened chemical compounds to identify those that mitigate the inflammatory response in cultured brain immune cells.