Opposing roles of GSDMD and NINJ1 shape early IL-1β dependent host defense during Toxoplasma gondii infection

Abstract

Inflammasome activation is a central component of host defense against Toxoplasma gondii, yet how downstream pyroptotic effectors shape infection outcomes remains incompletely understood. Here, we show that infection of primary macrophages with virulent type I T. gondii induces time-dependent NLRP3 inflammasome activation, caspase-1 cleavage, IL-1{beta} secretion, and cell death. Unexpectedly, although caspase-1/11 was required for parasite control, the pore-forming effector gasdermin D (GSDMD) limited host resistance. GSDMD-deficient macrophages and mice exhibited enhanced control of parasite replication, despite reduced cell death. Mechanistically, GSDMD deficiency uncoupled inflammasome activation from pyroptotic lysis, leading to accelerated and increased early IL-1{beta} release. Exogenous IL-1{beta} restored parasite control in wild-type macrophages, indicating that early cytokine availability is a key determinant of resistance. Enhanced control in GSDMD-deficient cells was associated with increased NLRP3 inflammasome assembly and was partially reversed by pharmacological inhibition of NLRP3, supporting a role for early inflammasome signaling in parasite restriction. In contrast, the membrane rupture mediator NINJ1 promoted host protection. NINJ1-deficient macrophages displayed impaired IL-1{beta} release and increased parasite replication, indicating that terminal cell lysis and cytokine release can be functionally dissociated. Pharmacological inhibition of GSDMD using disulfiram recapitulated the protective phenotype in both murine and human macrophages and reduced parasite burden in vivo, without directly affecting parasite viability. Together, these findings reveal that inflammasome-dependent cytokine production and pyroptotic cell death exert distinct and, in some cases, opposing roles during T. gondii infection. While NINJ1 supports protective responses, GSDMD-driven pyroptosis constrains early IL-1{beta}-mediated immunity. Targeting GSDMD may therefore represent a therapeutic strategy to enhance host control of intracellular pathogens.