A novel dual NLRP1 and NLRP3 inflammasome inhibitor for the treatment of inflammatory diseases.

Objectives: Inflammasomes induce maturation of the inflammatory cytokines IL-1ß and IL-18, whose activity is associated with the pathophysiology of a wide range of infectious and inflammatory diseases. As validated therapeutic targets for the treatment of acute and chronic inflammatory diseases, there has been intense interest in developing small-molecule inhibitors to target inflammasome activity and reduce disease-associated inflammatory burden. Methods: We examined the therapeutic potential of a novel small-molecule inhibitor, and associated derivatives, termed ADS032 to target and reduce inflammasome-mediated inflammation in vivo. In vitro, we characterised ADS032 function, target engagement and specificity. Results: We describe ADS032 as the first dual NLRP1 and NLRP3 inhibitor. ADS032 is a rapid, reversible and stable inflammasome inhibitor that directly binds both NLRP1 and NLRP3, reducing secretion and maturation of IL-1ß in human-derived macrophages and bronchial epithelial cells in response to the activation of NLPR1 and NLRP3. ADS032 also reduced NLRP3-induced ASC speck formation, indicative of targeting inflammasome formation. In vivo, ADS032 reduced IL-1ß and TNF-α levels in the serum of mice challenged i.p. with LPS and reduced pulmonary inflammation in an acute model of lung silicosis. Critically, ADS032 protected mice from lethal influenza A virus challenge, displayed increased survival and reduced pulmonary inflammation. Conclusion: ADS032 is the first described dual inflammasome inhibitor and a potential therapeutic to treat both NLRP1- and NLRP3-associated inflammatory diseases and also constitutes a novel tool that allows examination of the role of NLRP1 in human disease.

Fish Erythrocyte Extracellular Traps (FEETs) are an evolutionarily conserved cellular process triggered by different stimuli.

Fish erythrocytes remain nucleated, unlike mammalian erythrocytes that undergo enucleation during maturation. Besides oxygen transport, fish erythrocytes are capable of several immune defence processes and thus these cells are candidates for carrying out ETotic responses. ETosis is an evolutionarily conserved innate immune defence process found in both vertebrates and invertebrates, which involves the extrusion of DNA studded with antimicrobial effector proteins into the extracellular space that traps and kills microorganisms. In this present report, we demonstrate that erythrocytes from Danio rerio (zebrafish) produce ETotic-like responses when exposed to both chemical and physiological inducers of ETosis. Furthermore, erythrocytes from Salmo salar (Atlantic salmon) behaved in a similar way. We have termed these ET-like formations, as Fish Erythrocyte Extracellular Traps (FEETs). Several inducers of mammalian ETosis, such as the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) and the calcium ionophore ionomycin, induced FEETs. Moreover, we found that FEETs depend on the activation of PKC and generation of mitochondrial reactive oxygen species (mROS). This present report is the first demonstration that fish erythrocytes can exhibit ETotic-like responses, unveiling a previously unknown function, which sheds new light on the innate immune arsenal of these cells.