title: Trichothecene mycotoxins activate NLRP3 inflammasome through a P2X7 receptor and Src tyrosine kinase dependent pathway.
abstract: Inflammasome is an intracellular molecular platform of the innate immunity that is a key mediator of inflammation. The inflammasome complex detects pathogens and different danger signals, and triggers cysteine protease caspase-1-dependent processing of pro-inflammatory cytokines IL-1β, and IL-18 in dendritic cells and macrophages. Previously, we have shown that water-damaged building associated trichothecene mycotoxins, including roridin A, trigger IL-1β and IL-18 secretion in human macrophages. However, the molecular basis as well as mechanism behind this trichothecene-induced cytokine secretion has remained uncharacterized. Here, we show that the trichothecene-induced IL-1β secretion is dependent on NLRP3 inflammasome in human primary macrophages. Pharmacological inhibition and small interfering RNA approach showed that the trichothecene-induced NLRP3 inflammasome activation is mediated through ATP-gated P2X7 receptor. Moreover, we show that trichothecene-triggered NLRP3 inflammasome activation is dependent on Src tyrosine kinase activity. In addition, gene silencing of c-Cbl, a negative autophagy-related regulator of c-Src, resulted in enhanced secretion of IL-1β and IL-18 in response to trichothecene mycotoxin stimulation in human macrophages. In conclusion, our results suggest that roridin A, a fungal trichothecene mycotoxin, acts as microbial danger signals that trigger activation of NLRP3 inflammasome through P2X7R and Src tyrosine kinase signaling dependent pathway in human primary macrophages.
authors.affiliation: Finnish Institute of Occupational Health (FIOH), Topeliuksenkatu 41A, 00250 Helsinki, Finland. Electronic address: paivi.kankkunen@ttl.fi.
authors.forename: Päivi
authors.initials: P
authors.lastname: Kankkunen
authors.affiliation: Finnish Institute of Occupational Health (FIOH), Topeliuksenkatu 41A, 00250 Helsinki, Finland; Institute of Biotechnology, University of Helsinki, Finland.
authors.forename: Elina
authors.initials: E
authors.lastname: Välimäki
authors.affiliation: Finnish Institute of Occupational Health (FIOH), Topeliuksenkatu 41A, 00250 Helsinki, Finland.
authors.forename: Johanna
authors.initials: J
authors.lastname: Rintahaka
authors.affiliation: Finnish Institute of Occupational Health (FIOH), Topeliuksenkatu 41A, 00250 Helsinki, Finland.
authors.forename: Jaana
authors.initials: J
authors.lastname: Palomäki
authors.affiliation: Finnish Institute of Occupational Health (FIOH), Topeliuksenkatu 41A, 00250 Helsinki, Finland; Institute of Biotechnology, University of Helsinki, Finland.
authors.forename: Tuula
authors.initials: T
authors.lastname: Nyman
authors.affiliation: Finnish Institute of Occupational Health (FIOH), Topeliuksenkatu 41A, 00250 Helsinki, Finland.
authors.forename: Harri
authors.initials: H
authors.lastname: Alenius
authors.affiliation: Finnish Institute of Occupational Health (FIOH), Topeliuksenkatu 41A, 00250 Helsinki, Finland.
authors.forename: Henrik
authors.initials: H
authors.lastname: Wolff
authors.affiliation: Finnish Institute of Occupational Health (FIOH), Topeliuksenkatu 41A, 00250 Helsinki, Finland.
authors.forename: Sampsa
authors.initials: S
authors.lastname: Matikainen
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism; D002478:Cells, Cultured; D006801:Humans; D058847:Inflammasomes / Q000378:metabolism*; D020382:Interleukin-18 / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D008264:Macrophages / Q000276:immunology* / Q000382:microbiology; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D050721:Proto-Oncogene Proteins c-cbl / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D058486:Receptors, Purinergic P2X7 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D014255:Trichothecenes / Q000276:immunology*; D015854:Up-Regulation; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D058847:Inflammasomes; D020382:Interleukin-18; D053583:Interleukin-1beta; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C453881:NLRP3 protein, human; D034741:RNA, Small Interfering; D058486:Receptors, Purinergic P2X7; D014255:Trichothecenes; D050721:Proto-Oncogene Proteins c-cbl; D019061:src-Family Kinases; C038849:roridin A
keywords: 4-amino-3-(4-chlorophenyl)-1-(t-butyl)-1H-pyrazolo[3,4-d]pyrimidine, RLR, RIG-I-like receptors; AG126; AZ; AZ11645373; DAMP; NLR; NLR family, Pyrin domain containing; NLRP; NOD-like nucleotide-binding oligomerization domain; PP2; RU; danger associated molecular pattern; relative unit; siRNA; small ribonucleic acid interference; tyrphostin AG 126