Development of NLRP3 inhibitors for Alzheimer's disease

Abstract Background NLRP3 inflammasome is a cytosolic and multimeric protein complex that plays essential roles in innate immune responses. Dysregulation of this protein complex has been linked to neuroinflammation and the development of Alzheimer's disease. Therefore, NLRP3 inflammasome represents an attractive target for effective AD treatment development. Method Small molecule inhibitors based on a recently identified lead NLRP3 inhibitor were designed, synthesized, and biologically characterized using biochemical and cellular assays. In vivo selectivity and target engagement were also tested using mice and 3xTg AD mice. Result A series of analogs were successfully synthesized and a new chemical scaffold was also designed to provide NLRP3 inhibitors. Studies in murine macrophages demonstrated that the inhibitory potency can be improved by structural modifications and a new lead compound was identified with an IC50 of 0.1 µM. This lead compound also binds to the recombinant NLRP3 protein with a K D of 0.5 µM. Studies in mice also confirmed that this lead compound is a BBB penetrant. Further in vivo studies demonstrated that this lead compound selectively reduces the IL‐1ß and engage the NLRP3 inflammasome in 3xTg AD mice. Conclusion A new lead NLRP3 inhibitor was identified via medicinal chemistry optimization to show selective inhibition on the NLRP3 inflammasome both in vitro and in vivo. The results strongly encourage further testing of this lead inhibitor for its functional activity in AD mice.