Memantine nitrate MN-08 suppresses NLRP3 inflammasome activation to protect against sepsis-induced acute lung injury in mice

Sepsis is a life-threatening organ dysfunction with devastating consequences, prominent among which is lung damage. Memantine, an N-methyl-D-aspartic acid receptor (NMDAR) antagonist, is able to alleviate acute lung injury (ALI). Nitric oxide (NO) suppresses NLRP3 inflammasome activation against lipopolysaccharide (LPS)-induced septic shock. MN-08, a novel nitrate derivative of memantine, possesses both the ability to antagonize NMDAR and release NO. In the present study, we aimed to investigate the protective effects of MN-08 against LPS-induced systemic inflammation and septic lung injury in mice, and to explore the underlying mechanisms of MN-08 in LPS-induced mice and THP-1 macrophages. MN-08 significantly increased the survival rate of septic mice, alleviated LPS-induced sepsis in mice via improving systemic inflammatory response syndrome and immune dysfunction, and attenuated pulmonary injury and inflammatory infiltration. More importantly, the therapeutic benefit of MN-08 for sepsis was greater than that of memantine and dexamethasone. Mechanistically, MN-08 exerted anti-inflammatory activity through inhibiting nuclear translocation of NF-κB, activation of the MAPK signaling pathway and the signaling transduction of STAT3/NF-κB. In addition, MN-08 suppressed NLRP3 inflammasome activation. Taken together, our studies demonstrate that MN-08 may be a promising therapeutic agent for sepsis-induced acute lung injury.