Pyroptosis and Necroptosis Inhibitor Necrosulfonamide Prevents Lipopolysaccharide-Induced Inflammatory Hyperalgesia in Mice

Abstract Recent studies have demonstrated that two distinct forms of necrotic cell death, pyroptosis, and necroptosis, triggered by the lipid A part of lipopolysaccharide (LPS) are involved in the pathogenesis of several neurodegenerative diseases associated with neuroinflammation. It has been suggested that inhibition of gasdermin D (GSDMD)-mediated pyroptosis and/or mixed lineage kinase domain-like pseudokinase (MLKL)-mediated necroptosis may have a therapeutic potential in the treatment of inflammatory diseases of the central nervous system (CNS). However, the involvement of both types of cell death in LPS-induced inflammatory hyperalgesia remains unknown. Therefore, we aimed to investigate whether GSDMD and MLKL inhibitor, necrosulfonamide (NSA), prevents inflammatory hyperalgesia induced by LPS via inhibiting caspase-11/GSDMD-mediated pyroptosis and receptor-interacting serine/threonine-protein kinase (RIPK) 1/RIPK3/MLKL-mediated necroptosis in the CNS of mice. It was observed that 6 hours after intraperitoneal (i.p.) injection of LPS (10 mg/kg), the response time of mice to thermal stimulation determined by hot plate test was prevented with 0.01, 0.1, and 1 mg/kg (i.p.) doses of NSA. When NSA was administered at the lowest effective dose (0.01 mg/kg), it prevented the LPS-induced increase in caspase-11 p20, p30-GSDMD, interleukin-1β, high-mobility-group-box 1, and semaphorin (SEMA) protein expression as well as activity of RIPK1, RIPK3, and MLKL associated with decreased expression of myelin proteolipid protein (PLP) in the tissues of LPS-treated mice. Our findings suggested a decrease in the caspase-11/GSDMD-mediated pyroptosis, RIPK1/RIPK3/MLKL necrosome-mediated necroptosis, and remyelination inhibitor, SEMA3A, as well as increased expression of the main protein of the CNS myelin membrane, PLP, in the CNS of mice involves in the protective effect of NSA against inflammatory hyperalgesia induced by LPS.