ABSTRACT
Natterin is an aerolysin-like pore-forming toxin responsible for the toxic effects of the venom of the medically significant fish Thalassophryne nattereri. Using a combination of pharmacologic and genetic loss-of-function approaches we conduct a systematic investigation of the regulatory mechanisms that control Natterin-induced neutrophilic inflammation in the peritonitis model. Our data confirmed the capacity of Natterin to induce a strong and sustained neutrophilic inflammation leading to systemic inflammatory lung infiltration and revealed overlapping regulatory paths in its control. We found that Natterin induced the extracellular release of mature IL-1ß and the sustained production of IL-33 by bronchial epithelial cells. We confirmed the dependence of both ST2/IL-33 and IL-17A/IL-17RA signaling on the local and systemic neutrophils migration, as well as the crucial role of IL-1α, caspase-1 and caspase-11 for neutrophilic inflammation. The inflammation triggered by Natterin was a gasdermin-D-dependent inflammasome process, despite the cells did not die by pyroptosis. Finally, neutrophilic inflammation was mediated by non-canonical NLRP6 and NLRC4 adaptors through ASC interaction, independent of NLRP3. Our data highlight that the inflammatory process dependent on non-canonical inflammasome activation can be a target for pharmacological intervention in accidents by T. nattereri, which does not have adequate specific therapy.
Subject(s)
Caspase 1/metabolism , Caspases, Initiator/metabolism , Fish Venoms/pharmacology , Inflammasomes/metabolism , Inflammation/immunology , Interleukin-1beta/metabolism , Lung/drug effects , Neutrophil Infiltration/drug effects , Neutrophils/drug effects , Peritonitis/chemically induced , Receptors, Cell Surface/metabolism , Animals , Apoptosis Regulatory Proteins/genetics , Apoptosis Regulatory Proteins/metabolism , CARD Signaling Adaptor Proteins/genetics , CARD Signaling Adaptor Proteins/metabolism , Calcium-Binding Proteins/genetics , Calcium-Binding Proteins/metabolism , Caspase 1/genetics , Caspases, Initiator/genetics , Female , Inflammasomes/immunology , Inflammation Mediators/metabolism , Interleukin-1beta/genetics , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Lung/enzymology , Lung/immunology , Male , Mice, Inbred C57BL , Mice, Knockout , Neutrophils/enzymology , Neutrophils/immunology , Peritonitis/enzymology , Peritonitis/genetics , Peritonitis/immunology , Phosphate-Binding Proteins/genetics , Phosphate-Binding Proteins/metabolism , Pore Forming Cytotoxic Proteins , Receptors, Cell Surface/genetics , Receptors, Cell Surface/immunology , Signal TransductionABSTRACT
Natterin is an aerolysin-like pore-forming toxin responsible for the toxic effects of the venom of the medically significant fish Thalassophryne nattereri. Using a combination of pharmacologic and genetic loss-of-function approaches we conduct a systematic investigation of the regulatory mechanisms that control Natterin-induced neutrophilic inflammation in the peritonitis model. Our data confirmed the capacity of Natterin to induce a strong and sustained neutrophilic inflammation leading to systemic inflammatory lung infiltration and revealed overlapping regulatory paths in its control. We found that Natterin induced the extracellular release of mature IL-1β and the sustained production of IL-33 by bronchial epithelial cells. We confirmed the dependence of both ST2/IL-33 and IL-17A/IL-17RA signaling on the local and systemic neutrophils migration, as well as the crucial role of IL-1α, caspase-1 and caspase-11 for neutrophilic inflammation. The inflammation triggered by Natterin was a gasdermin-D-dependent inflammasome process, despite the cells did not die by pyroptosis. Finally, neutrophilic inflammation was mediated by non-canonical NLRP6 and NLRC4 adaptors through ASC interaction, independent of NLRP3. Our data highlight that the inflammatory process dependent on non-canonical inflammasome activation can be a target for pharmacological intervention in accidents by T. nattereri, which does not have adequate specific therapy.
