title: Non-transcriptional priming and deubiquitination regulate NLRP3 inflammasome activation.
abstract: The NLRP3 inflammasome is a key component of the innate immune response to pathogenic infection and tissue damage. It is also involved in the pathogenesis of a number of human diseases, including gouty arthritis, silicosis, atherosclerosis, and type 2 diabetes. The assembly of the NLRP3 inflammasome requires a priming signal derived from pattern recognition or cytokine receptors, followed by a second signal derived from extracellular ATP, pore-forming toxins, or crystalline materials. How these two signals activate the NLRP3 inflammasome is not yet clear. Here, we show that in mouse macrophages, signaling by the pattern recognition receptor TLR4 through MyD88 can rapidly and non-transcriptionally prime NLRP3 by stimulating its deubiquitination. This process is dependent on mitochondrial reactive oxygen species production and can be inhibited by antioxidants. We further show that signaling by ATP can also induce deubiquitination of NLRP3 by a mechanism that is not sensitive to antioxidants. Pharmacological inhibition of NLRP3 deubiquitination completely blocked NLRP3 activation in both mouse and human cells, indicating that deubiquitination of NLRP3 is required for its activation. Our findings suggest that NLRP3 is activated by a two-step deubiquitination mechanism initiated by Toll-like receptor signaling and mitochondrial reactive oxygen species and further potentiated by ATP, which could explain how NLRP3 is activated by diverse danger signals.
authors.affiliation: Department of Biochemistry and Molecular Biology and the Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Christine
authors.initials: C
authors.lastname: Juliana
authors.forename: Teresa
authors.initials: T
authors.lastname: Fernandes-Alnemri
authors.forename: Seokwon
authors.initials: S
authors.lastname: Kang
authors.forename: Andrew
authors.initials: A
authors.lastname: Farias
authors.forename: Fengsong
authors.initials: F
authors.lastname: Qin
authors.forename: Emad S
authors.initials: ES
authors.lastname: Alnemri
mesh_terms: D000255:Adenosine Triphosphate / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D058847:Inflammasomes / Q000235:genetics / Q000378:metabolism*; D007249:Inflammation / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008264:Macrophages / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism; D054875:Ubiquitination
chemical_list: D002352:Carrier Proteins; D058847:Inflammasomes; C507779:MYD88 protein, human; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C453881:NLRP3 protein, human; C492716:Nlrp3 protein, mouse; D017382:Reactive Oxygen Species; C495345:TLR4 protein, human; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D000255:Adenosine Triphosphate