MCC950-Derived NLRP3 Inflammasome Inhibitor Modulates Glial Inflammatory Signatures and Neuroinflammation after Traumatic Brain Injury

Abstract

The NLRP3 inflammasome is a central mediator of sterile inflammation and a key therapeutic target to modulate secondary neuroinflammation following traumatic brain injury (TBI). Although the widely used NLRP3 inhibitor MCC950 effectively suppresses inflammasome activation in preclinical models, its clinical development has been limited by safety concerns, underscoring the need for next-generation inhibitors with improved translational potential. Compound 4b, a structurally related N-sulfonylurea derivative, has been validated as an NLRP3 inhibitor in models of peripheral inflammation. However, whether its pharmacological activity translates to the central nervous system (CNS) neuroinflammatory context remains unexplored. Here, we studied the pharmacological activity of compound 4b in vitro and in vivo to assess its potential application in TBI. In primary mouse glial cultures, compound 4b inhibited NLRP3 inflammasome-mediated interleukin-1β (IL-1β) release in a concentration-dependent manner following activation by ATP, nigericin, or monosodium urate crystals. Consistently, compound 4b reduced ATP-induced inflammasome assembly, as indicated by decreased ASC speck formation. Acute administration of compound 4b (10 mg/kg, i.p.) 1 h post-TBI in a mouse model significantly improved neuromotor recovery and attenuated injury-associated body weight loss. These functional improvements were accompanied by reduced expression of proinflammatory and gliosis-related genes, as well as protein levels of IL-1β in brain tissue, indicating effective modulation of neuroinflammatory signaling. These findings demonstrate that compound 4b exerts NLRP3 inhibitory activity in CNS-resident innate immune cells and modulates neuroinflammation and functional recovery after TBI, supporting its further development as a mechanistically validated NLRP3 inhibitor with translational relevance.